国外数据库各学科高被引论文TOP5

2015-01-31 01:44
中国学术期刊文摘 2015年2期
关键词:出版物邮箱来源

高影响力文章

国外数据库各学科高被引论文TOP5

数据来源:Web of Science文献出版时间:2013.1—2014.11检索时间:2014.12.1

COMPUTER SCIENCE CYBERNETICS 计算机科学,控制论

被引频次: 63

来源出版物:Ieee Transactions on Cybernetics,2013,43(6): 1796-1806联系邮箱:Wu,ZG; nashwzhg@gmail.com

被引频次: 52

Distributed Synchronization in Networks of Agent Systems With Nonlinearities and Random Switchings

Tang,Y; Gao,HJ; Zou,W; et al.

Abstract: In this paper,the distributed synchronization problem of networks of agent systems with controllers and nonlinearities subject to Bernoulli switchings is investigated. Controllers and adaptive updating laws injected in each vertex of networks depend on the state information of its neighborhood. Three sets of Bernoulli stochastic variables are introduced to describe the occurrence probabilities of distributed adaptive controllers,updating laws and nonlinearities,respectively. By the Lyapunov functions method,we show that the distributed synchronization of networks composed of agent systems with multiple randomly occurring nonlinearities,multiple randomly occurring controllers,and multiple randomly occurring updating laws can be achieved in mean square under certain criteria. The conditions derived in this paper can be solved by semi-definite programming. Moreover,by mathematical analysis,we find that the coupling strength,the probabilities of the Bernoulli stochastic variables,and the form of nonlinearities have great impacts on the convergence speed and the terminal control strength. The synchronization criteria and the observed phenomena are demonstrated by several numerical simulation examples. In addition,the advantage of distributed adaptive controllers over conventional adaptive controllers is illustrated.

Keywords: complex dynamical networks; multiagent systems; neural-networks; exponential synchronization; adaptive synchronization;missing measurements; consensus seeking; stability; discrete; delay

来源出版物:Ieee Transactions on Cybernetics,2013,43(1): 358-370联系邮箱:Tang,Y; tangtany@gmail.com

被引频次: 36

Induced l(2)Filtering of Fuzzy Stochastic Systems With Time-Varying Delays

Su,XJ; Shi,P; Wu,LG; et al.

Abstract: This paper is concerned with the problem of induced l(2)filter design for a class of discrete-time Takagi-Sugeno fuzzy It stochastic systems with time-varying delays. Attention is focused on the design of the desired filter to guarantee an induced l(2)performance for the filtering error system. A new comparison model is proposed by employing a new approximation for the time-varying delay state,and then,sufficient conditions for the obtained filtering error system are derived by this comparison model. A desired filter is constructed by solving a convex optimization problem,which can be efficiently solved by standard numerical algorithms. Finally,simulation examples are provided to illustrate the effectiveness of the proposed approaches.

Keywords: networked nonlinear-systems; infinity model-reduction; feedback-control; packet dropouts; mixed delays; lmi approach; stability; design; quantization

来源出版物:Ieee Transactions on Cybernetics,2013,43(4): 1251-1264联系邮箱:Su,XJ; suxiaojie1985@gmail.com

被引频次: 33

Enhanced Computer Vision with Microsoft Kinect Sensor: A Review

Han,JG; Shao,L; Xu,D; et al.

Abstract: With the invention of the low-cost Microsoft Kinect sensor,high-resolution depth and visual(RGB)sensing has become available for widespread use. The complementary nature of the depth and visual information provided by the Kinect sensor opens up new opportunities to solve fundamental problems in computer vision. This paper presents a comprehensive review of recent Kinect-based computer vision algorithms and applications. The reviewed approaches are classified according to the type of vision problems that can be addressed or enhanced by means of the Kinect sensor. The covered topics include preprocessing,object tracking and recognition,human activity analysis,hand gesture analysis,and indoor 3-D mapping. For each category of methods,we outline their main algorithmic contributions and summarize their advantages/differences compared to their RGB counterparts. Finally,we give an overview of the challenges in this field and future research trends. This paper is expected to serve as a tutorial and source of references for Kinect-based computer vision researchers.

Keywords: object recognition; kernel descriptors; depth cameras; scale; calibration; features

来源出版物:Ieee Transactions on Cybernetics,2013,43(5): 1318-1334联系邮箱:Shao,L; jungonghan77@gmail.com

被引频次: 28

Decentralized Adaptive Pinning Control for Cluster Synchronization of Complex Dynamical Networks

Su,HS; Rong,ZH; Chen,MZQ; et al.

Abstract: In this brief,we investigate pinning control for cluster synchronization of undirected complex dynamical networks using a decentralized adaptive strategy. Unlike most existing pinning-control algorithms with or without an adaptive strategy,which require global information of the underlying network such as the eigenvalues of the coupling matrix of the whole network or a centralized adaptive control scheme,we propose a novel decentralized adaptive pinning-control scheme for cluster synchronization of undirected networks using a local adaptive strategy on both coupling strengths and feedback gains. By introducing this local adaptive strategy on each node,we show that the network can synchronize using weak coupling strengths and small feedback gains. Finally,we present some simulations to verify and illustrate the theoretical results.

Keywords: systems; oscillators; stability

来源出版物:Ieee Transactions on Cybernetics,2013,43(1): 394-399联系邮箱:Chen,MZQ; houshengsu@gmail.com

COMPUTER SCIENCE HARDWARE ARCHITECTURE 计算机科学,硬件和架构

被引频次: 103

Real-Time Implementation of Fault-Tolerant Control Systems With Performance Optimization

Yin,S; Luo,H; Ding,SX

Abstract: In this paper,two online schemes for an integrated design of fault-tolerant control(FTC)systems with application to Tennessee Eastman(TE)benchmark are proposed. Based on the data-driven design of the proposed fault-tolerant architecture whose core is an observer/residual generator based realization of the Youla parameterization of all stabilization controllers,FTC is achieved by an adaptive residual generator for the online identification of the fault diagnosis relevant vectors,and an iterative optimization method for system performance enhancement. The performance and effectiveness of the proposed schemes are demonstrated through the TE benchmark model.

Keywords: diagnosis; drives; identification; strategies; design

来源出版物:Ieee Transactions on Industrial Electronics,2014,61(5): 2402-2411联系邮箱:Yin,S; shen.yin2011@googlemail.com

被引频次: 80

Massive MIMO in the UL/DL of Cellular Networks: How Many Antennas Do We Need?

Hoydis,J; ten Brink,S; Debbah,M

Abstract: We consider the uplink(UL)and downlink(DL)of non-cooperative multi-cellular time-division duplexing(TDD)systems,assuming that the number N of antennas per base station(BS)and the number K of user terminals(UTs)per cell are large. Our system model accounts for channel estimation,pilot contamination,and an arbitrary path loss and antenna correlation for each link. We derive approximations of achievable rates with several linear precoders and detectors which are proven to be asymptotically tight,but accurate for realistic system dimensions,as shown by simulations. It is known from previous work assuming uncorrelated channels,that as N -> infinity while K is fixed,the system performance is limited by pilot contamination,the simplest precoders/detectors,i.e.,eigenbeamforming(BF)and matched filter(MF),are optimal,and the transmit power can be made arbitrarily small. We analyze to which extent these conclusions hold in the more realistic setting where N is not extremely large compared to K. In particular,we derive how many antennas per UT are needed to achieve eta% of the ultimate performance limit with infinitely many antennas and how many more antennas are needed with MF and BF to achieve the performance of minimum mean-square error(MMSE)detection and regularized zero-forcing(RZF),respectively.

Keywords: multiuser mimo; channel; wireless; systems

来源出版物:Ieee Journal on Selected Areas in Communications,2013,31(2): 160-171

联系邮箱:Hoydis,J; jakob.hoydis@alcatel-lucent.com

被引频次: 79

Adaptive Sliding-Mode Control for Nonlinear Active Suspension Vehicle Systems Using T-S Fuzzy Approach

Li,HY; Yu,JY; Hilton,C; et al.

Abstract: This paper deals with the adaptive sliding-mode control problem for nonlinear active suspension systems via the Takagi-Sugeno(T-S)fuzzy approach. The varying sprung and unsprung masses,the unknown actuator nonlinearity,and the suspension performances are taken into account simultaneously,and the corresponding mathematical model is established. The T-S fuzzy system is used to describe the original nonlinear system for the control-design aim via the sector nonlinearity approach. A sufficient condition is proposed for the asymptotical stability of the designing sliding motion. An adaptive sliding-mode controller is designed to guarantee the reachability of the specified switching surface. The condition can be converted to the convex optimization problems. Simulation results for a half-vehicle active suspension model are provided to demonstrate the effectiveness of the proposed control schemes.

Keywords: h-infinity control; time-delay; car model; feedback; design

来源出版物:Ieee Transactions on Industrial Electronics,2013,60(8): 3328-3338联系邮箱:Li,HY; lihongyi2009@gmail.com

被引频次: 79

Semipolar(20(2)over-bar(1)over-bar)InGaN/GaN Light-Emitting Diodes for High-Efficiency Solid-State Lighting

Feezell,DF; Speck,JS; DenBaars,SP; et al.

Abstract: This work examines the effects of polarization-related electric fields on the energy band diagrams,wavelength shift,wave function overlap,and efficiency droop for InGaN quantum wells on various crystal orientations,including polar(0001)(c-plane),semipolar(20(2)over bar1),semipolar(20(2)over bar(1)over bar),and non-polar(10(1)over bar0)(m-plane). Based on simulations,we show that the semipolar(20(2)over bar(1)over bar)orientation exhibits excellent potential for the development of high-efficiency,low-droop light-emitting diodes(LEDs). We then present recent advancements in crystal growth,optical performance,and thermal performance of semipolar(20(2)over bar(1)over bar)LEDs. Finally,we demonstrate a low-droop,high-efficiency single-quantum-well blue semipolar(20(2)over bar(1)over bar)LED with an external quantum efficiency of more than 50% at 100 A/cm2.

Keywords: quantum-wells; semiconductors; polarization

来源出版物:Journal of Display Technology,2013,9(4): 190-198联系邮箱:Feezell,DF; dfeezell@unm.edu

被引频次: 77

A Novel Control Design on Discrete-Time Takagi-Sugeno Fuzzy Systems With Time-Varying Delays

Su,XJ; Shi,P; Wu,LG; et al.

Abstract: This paper focuses on analyzing a new model transformation of discrete-time Takagi-Sugeno(T-S)fuzzy systems with time-varying delays and applying it to dynamic output feedback(DOF)controller design. A new comparison model is proposed by employing a new approximation for time-varying delay state,and then,a delay partitioning method is used to analyze the scaled small gain of this comparison model. A sufficient condition on discrete-time T-S fuzzy systems with time-varying delays,which guarantees the corresponding closed-loop system to be asymptotically stable and has an induced . 2 disturbance attenuation performance,is derived by employing the scaled small-gain theorem. Then,the solvability condition for the induced . 2 DOF control is also established,by which the DOF controller can be solved as linear matrix inequality optimization problems. Finally,examples are provided to illustrate the effectiveness of the proposed approaches.

Keywords: output-feedback control; h-infinity control; stability analysis; nonlinear-systems; lmi approach; fault-detection; model; stabilization

来源出版物:Ieee Transactions on Fuzzy Systems,2013,21(4): 655-671联系邮箱:Su,XJ; suxiaojie1985@gmail.com

COMPUTER SCIENCE INFORMATION SYSTEMS 计算机科学,信息系统

被引频次: 155

Liposomal drug delivery systems: From concept to clinical applications

Allen,TM; Cullis,PR

Abstract: The first closed bilayer phospholipid systems,called liposomes,were described in 1965 and soon were proposed as drug delivery systems. The pioneering work of countless liposome researchers over almost 5 decades led to the development of important technical ad-vances such as remote drug loading,extrusion for homogeneous size,long-circulating(PEGylated)liposomes,triggered release liposomes,liposomes containing nucleic acid polymers,ligand-targeted liposomes and liposomes containing combinations of drugs. These advances have led to numerous clinical trials in such diverse areas as the delivery of anti-cancer,anti-fungal and antibiotic drugs,the delivery of gene medicines,and the delivery of anesthetics and anti-inflammatory drugs. A number of liposomes(lipidic nanoparticles)are on the market,and many more are in the pipeline. Lipidic nanoparticles are the first nanomedicine delivery system to make the transition from concept to clinical application,and they are now an established technology platform with considerable clinical acceptance. We can look forward to many more clinical products in the future.

Keywords: sterically stabilized liposomes; long-circulating liposomes; large unilamellar vesicles; enzyme prodrug therapy; tumor-bearing mice; doxorubicin-containing liposomes; receptor-mediated endocytosis; convection-enhanced delivery; high-density lipoproteins; rapid extrusion procedure

来源出版物:Advanced Drug Delivery Reviews,2013,65(1): 36-48联系邮箱:Allen,TM; tallen@ualberta.ca

被引频次: 113

Structure-Function of the G Protein-Coupled Receptor Superfamily

Katritch,V; Cherezov,V; Stevens,RC

Abstract: During the past few years,crystallography of G protein-coupled receptors(GPCRs)has experienced exponential growth,resulting in the determination of the structures of 16 distinct receptors-9 of them in 2012 alone. Including closely related subtype homology models,this coverage amounts to approximately 12% of the human GPCR superfamily. The adrenergic,rhodopsin,and adenosine receptor systems are also described by agonist-bound active-state structures,including a structure of the receptor-G protein complex for the beta(2)-adrenergic receptor. Biochemical and biophysical techniques,such as nuclear magnetic resonance and hydrogen-deuterium exchange coupled with mass spectrometry,are providing complementary insights into ligand-dependent dynamic equilibrium between different functional states. Additional details revealed by high-resolution structures illustrate the receptors as allosteric machines that are controlled not only by ligands but also by ions,lipids,cholesterol,and water. This wealth of data is helping redefine our knowledge of how GPCRs recognize such a diverse array of ligands and how they transmit signals 30 angstroms across the cell membrane; it also is shedding light on a structural basis of GPCR allosteric modulation and biased signaling.

Keywords: beta(2)adrenergic-receptor; muscarinic acetylcholine-receptor; adenosine a(2a)receptor; structure-based discovery; histamine h-1 receptor; crystal-structure; conformational-changes; allosteric modulation; opioid receptor; drug discovery

来源出版物:Annual Review of Pharmacology and Toxicology,2013,53: 531-556联系邮箱:Katritch,V; stevens@scripps.edu

被引频次: 94

Cytochrome P450 enzymes in drug metabolism: Regulation of gene expression,enzyme activities,and impact of genetic variation

Zanger,UM; Schwab,M

Abstract: Cytochromes P450(CYP)are a major source of variability in drug pharmacokinetics and response. Of 57 putatively functional human CYPs only about a dozen enzymes,belonging to the CYP1,2,and 3 families,are responsible for the biotransformation of most foreign substances including 70%-80% of all drugs in clinical use. The highest expressed forms in liver are CYPs 3A4,2C9,2C8,2E1,and 1A2,while 2A6,2D6,2B6,2C19 and 3A5 are less abundant and CYPs 2J2,1A1,and 1B1 are mainly expressed extrahepatically. Expression of each CYP is influenced by a unique combination of mechanisms and factors including genetic polymorphisms,induction by xenobiotics,regulation by cytokines,hormones and during disease states,as well as sex,age,and others. Multiallelic genetic polymorphisms,which strongly depend on ethnicity,play a major role for the function of CYPs 2D6,2C19,2C9,2B6,3A5 and 2A6,and lead to distinct pharmacogenetic phenotypes termed as poor,intermediate,extensive,and ultrarapid metabolizers. For these CYPs,the evidence for clinical significance regarding adverse drug reactions(ADRs),drug efficacy and dose requirement is rapidly growing. Polymorphisms in CYPs 1A1,1A2,2C8,2E1,2J2,and 3A4 are generally less predictive,but new data on CYP3A4 show that predictive variants exist and that additional variants in regulatory genes or in NADPH: cytochrome P450 oxidoreductase(POR)can have an influence. Here we review the recent progress on drug metabolism activity profiles,interindividual variability and regulation of expression,and the functional and clinical impact of genetic variation in drug metabolizing P450s.

Keywords: human liver-microsomes; pregnane-x-receptor; constitutive androstane receptor; breast-cancer patients; single nucleotide polymorphisms; proton pump inhibitors; p450 oxidoreductase deficiency; antley-bixler-syndrome; messenger-rna levels; re cyp2d6 genotype

来源出版物:Pharmacology & Therapeutics,2013,138(1): 103-141联系邮箱:Zanger,UM; uli.zanger@ikp-stuttgart.de

被引频次: 90

OPINION Signalling bias in new drug discovery: detection,quantification and therapeutic impact

Kenakin,T; Christopoulos,A

Abstract: Agonists of seven-transmembrane receptors,also known as G protein-coupled receptors(GPCRs),do not uniformly activate all cellular signalling pathways linked to a given seven-transmembrane receptor(a phenomenon termed ligand or agonist bias); this discovery has changed how high-throughput screens are designed and how lead compounds are optimized for therapeutic activity. The ability to experimentally detect ligand bias has necessitated the development of methods for quantifying agonist bias in a way that can be used to guide structure activity studies and the selection of drug candidates. Here,we provide a viewpoint on which methods are appropriate for quantifying bias,based on knowledge of how cellular and intracellular signalling proteins control the conformation of seven-transmembrane receptors. We also discuss possible predictions of how biased molecules may perform in vivo,and what potential therapeutic advantages they may provide.

Keywords: protein-coupled receptors; beta(2)adrenergic-receptor; mu-opioid receptor; functional selectivity; allosteric modulation; conformational-changes; heart-failure; active state; in-vivo; pharmacological agonism

来源出版物:Nature Reviews Drug Discovery,2013,12(3): 205-216联系邮箱:Kenakin,T; kenakin@email.unc.edu

被引频次: 90

The EPR effect for macromolecular drug delivery to solid tumors: Improvement of tumor uptake,lowering of systemic toxicity,and distinct tumor imaging in vivo

Maeda,H; Nakamura,H; Fang,J

Abstract: The EPR effect results from the extravasation of macromolecules or nanoparticles through tumor blood vessels. We here provide a historical review of the EPR effect including its features,vascular mediators found in both cancer and inflamed tissue. In addition,architectural and physiological differences of tumor blood vessels vs that of normal tissue are commented. Furthermore,methods of augmentation of the EPR effect are described,that result in better tumor delivery and improved therapeutic effect,where nitroglycerin,angiotensin I-converting enzyme(ACE)inhibitor,or angiotensin II-induced hypertension are employed. Consequently,better therapeutic effect and reduced systemic toxicity are generally observed. Obviously,the EPR effect based delivery of nanoprobes are also useful for tumor-selective imaging agents with using fluorescent or radio nuclei in nanoprobes. We also commented a key difference between passive tumor targeting and the EPR effect in tumors,particularly as related to drug retention in tumors: passive targeting of low-molecular-weight X-ray contrast agents involves a retention period of less than a few minutes,whereas the EPR effect of nanoparticles involves a prolonged retention time days to weeks.

Keywords: enhanced vascular-permeability; elevating blood-pressure; kinin-generating cascade; nitric-oxide scavenger; oily contrast-medium; molecular-weight; hageman-factor; cancer-chemotherapy; serratial protease; targeted delivery

来源出版物:Advanced Drug Delivery Reviews,2013,65(1): 71-79联系邮箱:Maeda,H; hirmaeda@ph.sojo-u.ac.jp

COMPUTER SCIENCE INTERDISCIPLINARY APPLICATIONS 计算机科学,跨学科应用

被引频次: 313

GROMACS 4.5: a high-throughput and highly parallel open source molecular simulation toolkit

Pronk,S; Pall,S; Schulz,R; et al.

Abstract: Motivation: Molecular simulation has historically been a low-throughput technique,but faster computers and increasing amounts of genomic and structural data are changing this by enabling large-scale automated simulation of,for instance,many conformers or mutants of biomolecules with or without a range of ligands. At the same time,advances in performance and scaling now make it possible to model complex biomolecular interaction and function in a manner directly testable by experiment. These applications share a need for fast and efficient software that can be deployed on massive scale in clusters,web servers,distributed computing or cloud resources.

Results: Here,we present a range of new simulation algorithms and features developed during the past 4 years,leading up to the GROMACS 4.5 software package. The software now automatically handles wide classes of biomolecules,such as proteins,nucleic acids and lipids,and comes with all commonly used force fields for these molecules built-in. GROMACS supports several implicit solvent models,as well as new free-energy algorithms,and the software now uses multithreading for efficient parallelization even on low-end systems,including windows-based workstations. Together with hand-tuned assembly kernels and state-of-the-art parallelization,this provides extremely high performance and cost efficiency for high-throughput as well as massively parallel simulations.

Keywords: force-field; free-energy; biomolecular simulation; dynamics; model; refinement; transition; efficient; constant; proteins

来源出版物:Bioinformatics,2013,29(7): 845-854联系邮箱:Lindahl,E; erik.lindahl@scilifelab.se

被引频次: 228

Progress,Challenges,and Opportunities in Two-Dimensional Materials Beyond Graphene

Butler,SZ; Hollen,SM; Cao,LY; et al.

Abstract: Graphene's success has shown that it is possible to create stable,single and few-atom-thick layers of van der Waals materials,and also that these materials can exhibit fascinating and technologically useful properties. Here we review the state-of-the-art of 2D materials beyond graphene. Initially,we will outline the different chemical classes of 2D materials and discuss the various strategies to prepare single-layer,few-layer,and multilayer assembly materials in solution,on substrates,and on the wafer scale. Additionally,we present an experimental guide for identifying and characterizing single-layer-thick materials,as well as outlining emerging techniques that yield both local and global information. We describe the differences that occur in the electronic structure between the bulk and the single layer and discuss various methods of tuning their electronic properties by manipulating the surface. Finally,we highlight the properties and advantages of single-,few-,and many-layer 2D materials in field-effect transistors,spin- and valley-tronics,thermoelectrics,and topological insulators,among many other applications.

Keywords: chemical-vapor-deposition; der-waals epitaxy; hexagonal boron-nitride; single-layer mos2; field-effect transistors; transitionmetal dichalcogenides; scanning-tunneling-microscopy; topological insulator nanoribbons; lithium intercalation properties; langmuirblodgett deposition

来源出版物:Acs Nano,2013,7(4): 2898-2926联系邮箱:Goldberger,JE; goldberger@chemistry.ohio-state.edu

被引频次: 200

Chemical Management for Colorful,Efficient,and Stable Inorganic-Organic Hybrid Nanostructured Solar Cells

Noh,JH; Im,SH; Heo,JH; et al.

Abstract: Chemically tuned inorganic-organic hybrid materials,based on CH3NH3(==MA)Pb(I1-xBrx)3perovskites,have been studied using UV-vis absorption and X-ray diffraction patterns and applied to nanostructured solar cells. The band gap engineering brought about by the chemical management of MAPb(I1-xBrx)3perovskites can be controllably tuned to cover almost the entire visible spectrum,enabling the realization of colorful solar cells. We demonstrate highly efficient solar cells exhibiting 12.3% in a power conversion efficiency of under standard AM 1.5,for the most efficient device,as a result of tunable composition for the light harvester in conjunction with a mesoporous TiO2film and a hole conducting polymer. We believe that the works highlighted in this paper represent one step toward the realization of low-cost,high-efficiency,and long-term stability with colorful solar cells.

Keywords: organometal halide perovskites; nanowires; crystals

来源出版物:Nano Letters,2013,13(4): 1764-1769联系邮箱:Seok,SI; seoksi@krict.re.kr

被引频次: 184

Sodium-Ion Batteries

Slater,MD; Kim,D; Lee,E; et al.

Abstract: The status of ambient temperature sodium ion batteries is reviewed in light of recent developments in anode,electrolyte and cathode materials. These devices,although early in their stage of development,are promising for large-scale grid storage applications due to the abundance and very low cost of sodium-containing precursors used to make the components. The engineering knowledge developed recently for highly successful Li ion batteries can be leveraged to ensure rapid progress in this area,although different electrode materials and electrolytes will be required for dual intercalation systems based on sodium. In particular,new anode materials need to be identified,since the graphite anode,commonly used in lithium systems,does not intercalate sodium to any appreciable extent. A wider array of choices is available for cathodes,including high performance layered transition metal oxides and polyanionic compounds. Recent developments in electrodes are encouraging,but a great deal of research is necessary,particularly in new electrolytes,and the understanding of the SEI films. The engineering modeling calculations of Na-ion battery energy density indicate that 210 Wh kg-1in gravimetric energy is possible for Na-ion batteries compared to existing Li-ion technology if a cathode capacity of 200 mAh g-1and a 500 mAh g-1anode can be discovered with an average cell potential of 3.3 V.

Keywords: rechargeable lithium batteries; electrochemical insertion; cathode material; nanocrystalline Fe3O4; negative electrodes; petroleum cokes; phase-diagram; Na; intercalation; carbon

来源出版物:Advanced Functional Materials,2013,23(8): 947-958联系邮箱:Slater,MD; cjohnson@anl.gov

被引频次: 154

Perovskites: The Emergence of a New Era for Low-Cost,High-Efficiency Solar Cells

Snaith,HJ

Abstract: Over the last 12 months,we have witnessed an unexpected breakthrough and rapid evolution in the field of emerging photovol-taics,with the realization of highly efficient solid-state hybrid solar cells based on organometal trihalide perovskite absorbers. In this Perspective,the steps that have led to this discovery are discussed,and the future of this rapidly advancing concept have been considered. It is likely that the next few years of solar research will advance this technology to the very highest efficiencies while retaining the very lowest cost and embodied energy. Provided that the stability of the perovskite-based technology can be proven,we will witness the emergence of a contender for ultimately low-cost solar power.

Keywords: organometal halide perovskites; photovoltaic cells; heterojunctions; semiconductors; electrodes; deposition; 20-percent; conversion; absorbers; layer

来源出版物:Journal of Physical Chemistry Letters,2013,4(21): 3623-3630联系邮箱:Snaith,HJ; h.snaith1@physics.ox.ac.uk

COMPUTER SCIENCE SOFTWARE ENGINEERING 计算机科学,软件工程

被引频次: 38

Real-Time Human Pose Recognition in Parts from Single Depth Images

Shotton,J; Sharp,T; Kipman,A; et al.

Abstract: We propose a new method to quickly and accurately - predict human pose-the 3D positions of body joints-from a single depth image,without depending on information from preceding frames. Our approach is strongly rooted in current object recognition strategies. By designing an intermediate - representation in terms of body parts,the difficult pose estimation problem is transformed into a simpler per-pixel classification problem,for which efficient machine learning techniques exist. By using computer graphics to synthesize a very large dataset of training image pairs,one can train a classifier that estimates body part labels from test images invariant to pose,body shape,clothing,and other irrelevances. Finally,we generate confidence-scored 3D proposals of several body joints by reprojecting the classification result and finding local modes.

The system runs in under 5 ms on the Xbox 360. Our evaluation shows high accuracy on both synthetic and real test sets,and investigates the effect of several training parameters. We achieve state-of-the-art accuracy in our comparison with related work and demonstrate improved generalization over exact whole-skeleton nearest neighbor matching.

来源出版物:Communications of The Acm,2013,56(1): 116-124联系邮箱:Shotton,J; jamiesho@microsoft.com

被引频次: 31

Feature location in source code: a taxonomy and survey

Dit,B; Revelle,M; Gethers,M; et al.

Abstract: Feature location is the activity of identifying an initial location in the source code that implements functionality in a software system. Many feature location techniques have been introduced that automate some or all of this process,and a comprehensive overview of this large body of work would be beneficial to researchers and practitioners. This paper presents a systematic literature survey of feature location techniques. Eighty-nine articles from 25 venues have been reviewed and classified within the taxonomy in order to organize and structure existing work in the field of feature location. The paper also discusses open issues and defines future directions in the field of feature location.

Keywords: independent component analysis; static noninteractive approach; latent dirichlet allocation; information-retrieval; program comprehension; software evolution; feature identification; probabilistic ranking; maintenance tasks; dynamic-analysis

来源出版物:Journal of Software-evolution and Process,2013,25(1): 53-95联系邮箱:Poshyvanyk,D; denys@cs.wm.edu

被引频次: 29

An opposition-based differential evolution algorithm for permutation flow shop scheduling based on diversity measure

Li,XT; Yin,MH

Abstract: The permutation flow shop problem(PFSSP)is an NP-hard problem of wide engineering and theoretical background. In this paper,a differential evolution(DE)based memetic algorithm,named ODDE,is proposed for PFSSP. First,to make DE suitable for PFSSP,a new LRV rule based on random key is introduced to convert the continuous position in DE to the discrete job permutation. Second,the NEH heuristic was combined the random initialization to the population with certain quality and diversity. Third,to improve the global optimization property of DE,a DE approach based on measure of population's diversity is proposed to tuning the crossover rate. Fourth,to improve the convergence rate of DE,the opposition-based DE employs opposition-based learning for the initialization and for generation jumping to enhance the global optimal solution. Fifth,the fast local search is used for enhancing the individuals with a certain probability. Sixth,the pairwise based local search is used to enhance the global optimal solution and help the algorithm to escape from local minimum. Additionally,simulations and comparisons based on PFSSP benchmarks are carried out,which show that our algorithm is both effective and efficient. We have also evaluated our algorithm with the well known DMU problems. For the problems with the objective of minimizing makespan,the algorithm ODDE obtains 24 new upper bounds of the 40 instances,and for the problems with the objective of maximumlateness,ODDE obtains 137 new upper bounds of the 160 instances. These new upper bounds can be used for future algorithms to compare their results with ours.

Keywords: particle swarm optimization; local search algorithm; sequencing problem; genetic algorithm; heuristic algorithm; makespan criterion; minimization

来源出版物:Advances in Engineering Software,2013,55: 10-31联系邮箱:Yin,MH; Minghao.Yin1@gmail.com

被引频次: 23

An Effective CU Size Decision Method for HEVC Encoders

Shen,LQ; Liu,Z; Zhang,XP; et al.

Abstract: The emerging high efficiency video coding standard(HEVC)adopts the quadtree-structured coding unit(CU). Each CU allows recursive splitting into four equal sub-CUs. At each depth level(CU size),the test model of HEVC(HM)performs motion estimation(ME)with different sizes including 2N x 2N,2N x N,N x 2N,and N x N. ME process in HM is performed using all the possible depth levels and prediction modes to find the one with the least rate distortion(RD)cost using Lagrange multiplier. This achieves the highest coding efficiency but requires a very high computational complexity. In this paper,we propose a fast CU size decision algorithm for HM. Since the optimal depth level is highly content-dependent,it is not efficient to use all levels. We can determine CU depth range(including the minimum depth level and the maximum depth level)and skip some specific depth levels rarely used in the previous frame and neighboring CUs. Besides,the proposed algorithm also introduces early termination methods based on motion homogeneity checking,RD cost checking and SKIP mode checking to skip ME on unnecessary CU sizes. Experimental results demonstrate that the proposed algorithm can significantly reduce computational complexity while maintaining almost the same RD performance as the original HEVC encoder.

来源出版物:IEEE Transactions on Multimedia,2013,15(2): 465-470联系邮箱:Shen,LQ; jsslq@163.com

被引频次: 21

The evolution,challenges,and future of knowledge representation in product design systems

Chandrasegaran,SK; Ramani,K; Sriram,RD; et al.

Abstract: Product design is a highly involved,often ill-defined,complex and iterative process,and the needs and specifications of the required artifact get more refined only as the design process moves toward its goal. An effective computer support tool that helps the designer make better-informed decisions requires efficient knowledge representation schemes. In today's world,there is a virtual explosion in the amount of raw data available to the designer,and knowledge representation is critical in order to sift through this data and make sense of it. In addition,the need to stay competitive has shrunk product development time through the use of simultaneous and collaborative design processes,which depend on effective transfer of knowledge between teams. Finally,the awareness that decisions made early in the design process have a higher impact in terms of energy,cost,and sustainability,has resulted in the need to project knowledge typically required in the later stages of design to the earlier stages. Research in design rationale systems,product families,systems engineering,and ontology engineering has sought to capture knowledge from earlier product design decisions,from the breakdown of product functions and associated physical features,and from customer requirements and feedback reports. VR(Virtual reality)systems and multidisciplinary modeling have enabled the simulation of scenarios in the manufacture,assembly,and use of the product. This has helped capture vital knowledge from these stages of the product life and use it in design validation and testing. While there have been considerable and significant developments in knowledge capture and representation in product design,it is useful to sometimes review our position in the area,study the evolution of research in product design,and from past and current trends,try and foresee future developments. The goal of this paper is thus to review both our understanding of the field and the support tools that exist for the purpose,and identify the trends and possible directions research can evolve in the future.

Keywords: computer-aided-design; of-the-art; biologically inspired design; working situation model; engineering design; conceptual design; virtual-reality; special-issue; collaborative design; family design

来源出版物:Computer-aided Design,2013,45(2): 204-228联系邮箱:Ramani,K; ramani@purdue.edu

COMPUTER SCIENCE THEORY METHODS 计算机科学,理论与方法

被引频次: 124

Data-driven monitoring for stochastic systems and its application on batch process

Yin,S; Ding,SX; Sari,AHA; et al.

Abstract: Batch processes are characterised by a prescribed processing of raw materials into final products for a finite duration and play an important role in many industrial sectors due to the low-volume and high-value products. Process dynamics and stochastic disturbances are inherent characteristics of batch processes,which cause monitoring of batch processes a challenging problem in practice. To solve this problem,a subspace-aided data-driven approach is presented in this article for batch process monitoring. The advantages of the proposed approach lie in its simple form and its abilities to deal with stochastic disturbances and process dynamics existing in the process. The kerneldensity estimation,which serves as a non-parametric way of estimating the probability density function,is utilised for threshold calculation. An industrial benchmark of fed-batch penicillin production is finally utilised to verify the effectiveness of the proposed approach.

Keywords: principal component analysis; subspace identification; fault-detection; missing measurements; model; diagnosis; pca

来源出版物:International Journal of Systems Science,2013,44(7): 1366-1376联系邮箱:Yin,S; shen.yin@uni-due.de

被引频次: 52

Mobile cloud computing: A survey

Fernando,N; Loke,SW; Rahayu,W

Abstract: Despite increasing usage of mobile computing,exploiting its full potential is difficult due to its inherent problems such as resource scarcity,frequent disconnections,and mobility. Mobile cloud computing can address these problems by executing mobile applications on resource providers external to the mobile device. In this paper,we provide an extensive survey of mobile cloud computing research,while highlighting the specific concerns in mobile cloud computing. We present a taxonomy based on the key issues in this area,and discuss the different approaches taken to tackle these issues. We conclude the paper with a critical analysis of challenges that have not yet been fully met,and highlight directions for future work.

Keywords: systems; energy; infrastructure; management; bluetooth; devices

来源出版物:Future Generation Computer Systems-the International Journal of Grid Computing and Escience,2013,29(1): 84-106

联系邮箱:Fernando,N; niro_ucsc@yahoo.com

被引频次: 51

Distributed Synchronization of Coupled Neural Networks via Randomly Occurring Control

Tang,Y; Wong,WK

Abstract: In this paper,we study the distributed synchronization and pinning distributed synchronization of stochastic coupled neural networks via randomly occurring control. Two Bernoulli stochastic variables are used to describe the occurrences of distributed adaptive control and updating law according to certain probabilities. Both distributed adaptive control and updating law for each vertex in a network depend on state information on each vertex's neighborhood. By constructing appropriate Lyapunov functions and employing stochastic analysis techniques,we prove that the distributed synchronization and the distributed pinning synchronization of stochastic complex networks can be achieved in mean square. Additionally,randomly occurring distributed control is compared with periodically intermittent control. It is revealed that,although randomly occurring control is an intermediate method among the three types of control in terms of control costs and convergence rates,it has fewer restrictions to implement and can be more easily applied in practice than periodically intermittent control.

Keywords: complex dynamical network; adaptive synchronization; pinning control; systems; stability; controllability; criteria; chaos; array;delay

来源出版物:Ieee Transactions on Neural Networks and Learning Systems,2013,24(3): 435-447

联系邮箱:Tang,Y; tangtany@gmail.com

被引频次: 43

Multisensor data fusion: A review of the state-of-the-art

Khaleghi,B; Khamis,A; Karray,FO; et al.

Abstract: There has been an ever-increasing interest in multi-disciplinary research on multisensor data fusion technology,driven by its versatility and diverse areas of application. Therefore,there seems to be a real need for an analytical review of recent developments in the data fusion domain. This paper proposes a comprehensive review of the data fusion state of the art,exploring its conceptualizations,benefits,and challenging aspects,as well as existing methodologies. In addition,several future directions of research in the data fusion community are highlighted and described.

Keywords: hypothesis density filter; dempster-shafer theory; fuzzy rough sets; information fusion; sensor data; decentralized estimation;performance evaluation; sequence measurements; combination rules; belief functions

来源出版物:Information Fusion,2013,14(1): 28-44联系邮箱:Khaleghi,B; bkhalegh@ece.uwaterloo.ca

被引频次: 38

Real-Time Human Pose Recognition in Parts from Single Depth Images

Shotton,J; Sharp,T; Kipman,A; et al.

Abstract: We propose a new method to quickly and accurately - predict human pose-the 3D positions of body joints-from a single depth image,without depending on information from preceding frames. Our approach is strongly rooted in current object recognition strategies. By designing an intermediate - representation in terms of body parts,the difficult pose estimation problem is transformed into a simplerper-pixel classification problem,for which efficient machine learning techniques exist. By using computer graphics to synthesize a very large dataset of training image pairs,one can train a classifier that estimates body part labels from test images invariant to pose,body shape,clothing,and other irrelevances. Finally,we generate confidence-scored 3D proposals of several body joints by reprojecting the classification result and finding local modes.

The system runs in under 5ms on the Xbox 360. Our evaluation shows high accuracy on both synthetic and real test sets,and investigates the effect of several training parameters. We achieve state-of-the-art accuracy in our comparison with related work and demonstrate improved generalization over exact whole-skeleton nearest neighbor matching.

来源出版物:Communications of The Acm,2013,56(1): 116-124联系邮箱:Shotton,J; jamiesho@microsoft.com

CONSTRUCTION BUILDING TECHNOLOGY 建筑与建筑技术

被引频次: 31

Does e-cigarette consumption cause passive vaping?

Schripp,T; Markewitz,D; Uhde,E; et al.

Abstract: Electronic cigarette consumption(vaping)is marketed as an alternative to conventional tobacco smoking. Technically,a mixture of chemicals containing carrier liquids,flavors,and optionally nicotine is vaporized and inhaled. The present study aims at the determination of the release of volatile organic compounds(VOC)and(ultra)fine particles(FP/UFP)from an e-cigarette under near-to-real-use conditions in an 8-m3emission test chamber. Furthermore,the inhaled mixture is analyzed in small chambers. An increase in FP/UFP and VOC could be determined after the use of the e-cigarette. Prominent components in the gas-phase are 1,2-propanediol,1,2,3-propanetriol,diacetin,flavorings,and traces of nicotine. As a consequence,passive vaping must be expected from the consumption of e-cigarettes. Furthermore,the inhaled aerosol undergoes changes in the human lung that is assumed to be attributed to deposition and evaporation. Practical Implications The consumption of e-cigarettes marks a new source for chemical and aerosol exposure in the indoor environment. To evaluate the impact of e-cigarettes on indoor air quality and to estimate the possible effect of passive vaping,information about the chemical characteristics of the released vapor is needed.

Keywords: volatile organic-compounds; propylene-glycol; tobacco-smoke; formaldehyde; restaurants; cartridges; nicotine; bars; ban

来源出版物:Indoor Air,2013,23(1): 25-31联系邮箱:Schripp,T; tobias.schripp@wki.fraunhofer.de

被引频次: 28

Recent research and applications of GPS-based monitoring technology for high-rise structures

Yi,TH; Li,HN; Gu,M

Abstract: Monitoring the response of structures,especially tall buildings,under severe loading conditions is an important requirement for the validation of their design and construction,as well as being a maintenance concern. This paper presents a review of current research and development activities(since 1995)in the field of high-rise structure health monitoring using the Global Positioning System(GPS). The GPS monitoring technology and its accurate assessment method are firstly briefly described. Then,the progresses on monitoring the displacement of the high-rise structure caused by the ambient effects including wind,thermal variation,and earthquake-induced responses are discussed in details. Following that,the states of the art of augmenting the GPS monitoring technology are reviewed. Finally,existing problems and promising research efforts in the GPS-based health monitoring are given.

Keywords: wind-induced response; tall buildings; dynamic-response; system; displacement; accuracy

来源出版物:Structural Control & Health Monitoring,2013,20(5): 649-670联系邮箱:Yi,TH; yth@dlut.edu.cn

被引频次: 28

Review of passive PCM latent heat thermal energy storage systems towards buildings' energy efficiency

Soares,N; Costa,JJ; Gaspar,AR; et al.

Abstract: This paper aims to explore how and where phase change materials(PCMs)are used in passive latent heat thermal energy storage(LHTES)systems,and to present an overview of how these construction solutions are related to building's energy performance. A survey on research trends are firstly presented followed by the discussion of some physical and theoretical considerations about the building and the potential of integrating PCMs in construction elements. The different types of PCMs and main criteria that govern their selection are reviewed,as well as the main methods to measure PCMs' thermal properties,and the techniques to incorporate PCMs into building elements. The numerical modeling of heat transfer with phase-change and heat transfer enhanced techniques are discussed,followed by a review of several passive LHTES systems with PCMs. Studies on dynamic simulation of energy in buildings(DSEB)incorporating PCMs are reviewed,mainly those supported by EnergyPlus,ESP-r and TRNSYS software tools. Lifecycle assessments,both environmental and economic are discussed. This review shows that passive construction solutions with PCMs provide the potential for reducing energy consumption for heating and cooling due to the load reduction/shifting,and for increasing indoor thermal comfort due to the reduced indoor temperature fluctuations.

Keywords: phase-change materials; life-cycle assessment; shape-stabilized pcm; t-history method; change material wallboard; carbon-fiber brushes; numerical-simulation; residential buildings; multiobjective optimization; conductivity enhancement

来源出版物:Energy and Buildings,2013,59: 82-103联系邮箱:Soares,N; nelson.soares@dem.uc.pt

被引频次: 20

Durability of recycled aggregate concrete

Thomas,C; Setien,J; Polanco,JA; et al.

Abstract: This paper presents the main results of the research carried out to analyse the physical,mechanical and durability properties of concrete incorporating recycled aggregate. One of the most unknown aspects of recycled aggregate concretes is related to their durability in aggressive environments. Also most of the results found in the literature are not comparable due to the heterogeneity of the recycled aggregates,water/cement ratios and types of cement used. In this research,recycled aggregate concrete with partial and total coarse aggregate replacement and reference concretes with 24 water/cement ratios have been cast to study their physical and mechanical properties,behaviour under accelerated carbonation,water and oxygen permeability. The results show,for the same w/c ratio,the influence of the recycled aggregate on the concretes. The durability of the concretes made with recycled aggregate is worse due to the intrinsic porosity of them. These differences decrease for low w/c ratios,as in this case the most influential factor is the low porosity obtained in the new improved cement paste. Considering the mechanical properties,the influence of the recycled aggregate is worse for the high w/c ratios. On the basis of the results obtained,recommendable mixtures for recycled aggregates in aggressive environments will be suggested. Also,an experimental model from the recycled aggregate concretes compressive strength is proposed.

Keywords: coarse aggregate; mechanical-properties; reinforced-concrete; strength; mortar; waste; construction; performance

来源出版物:Construction and Building Materials,2013,40: 1054-1065联系邮箱:Thomas,C; carlos.thomas@unican.es

被引频次: 20

A multi-stage optimization method for cost-optimal and nearly-zero-energy building solutions in line with the EPBD-recast 2010

Hamdy,M; Hasan,A; Siren,K

Abstract: Finding cost-optimal solutions towards nearly-zero-energy buildings(nZEBs)in accordance with European energy performance of buildings directive(EPBD-recast 2010)is a challenging task. It requires exploring a huge number of possible combinations of energy-saving measures(ESMs)and energy-supply systems including renewable energy sources CRESS),under a comparative framework methodology. The current study introduces efficient,transparent,and time-saving simulation-based optimization method for such explorations. The method is applied to find the cost-optimal and nZEB energy performance levels for a study case of a single-family house in Finland. Different options of building-envelope parameters,heat-recovery units,and heating/cooling systems as well as various sizes of thermal and photovoltaic solar systems are explored as design options via three-stage optimization. The resulted economic and environmental trade-offs show that primary energy consumption ≥ 93 and ≤ 103 kWh/m2a is a cost-optimal energy performance level. It is economically feasible to achieve nZEB with 70 kWh/m2a. However,incentives(e.g.,energy credits)are required to reach lower-environmental-impact houses. Investing in low-operating-cost environmentally friendly heating system(e.g. ground source heat pump)is a key element for optimal solutions. The optimal implementation of ESMs and RES depends significantly on the installed heating/cooling system and the escalation rate of the energy price.

Keywords: life-cycle cost; residential buildings; heating-systems; performance; design; house; dwellings

来源出版物:Energy and Buildings,2013,56: 189-203联系邮箱:Hamdy,M; Mohamed.Hassan@aalto.fi

CRITICAL CARE MEDICINE 危重病急救医学

被引频次: 514

Surviving Sepsis Campaign: International Guidelines for Management of Severe Sepsis and Septic Shock: 2012

Dellinger,RP; Levy,MM; Rhodes,A; et al.

Abstract: Objective: To provide an update to the "Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock," last published in 2008.

Design: A consensus committee of 68 international experts representing 30 international organizations was convened. Nominal groups were assembled at key international meetings(for those committee members attending the conference). A formal conflict of interest policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independent of any industry funding. A stand-alone meeting was held for all subgroup heads,co- and vice-chairs,and selected individuals. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development.

Methods: The authors were advised to follow the principles of the Grading of Recommendations Assessment,Development and Evaluation(GRADE)system to guide assessment of quality of evidence from high(A)to very low(D)and to determine the strength of recommendations as strong(1)or weak(2). The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasized. Some recommendations were ungraded(UG). Recommendations were classified into three groups: 1)those directly targeting severe sepsis; 2)those targeting general care of the critically ill patient and considered high priority in severe sepsis; and 3)pediatric considerations.

Results: Key recommendations and suggestions,listed by category,include: early quantitative resuscitation of the septic patient during the first 6 hrs after recognition(1C); blood cultures before antibiotic therapy(1C); imaging studies performed promptly to confirm a potential source of infection(UG); administration of broad-spectrum antimicrobials therapy within 1 hr of recognition of septic shock(1B)and severe sepsis without septic shock(1C)as the goal of therapy; reassessment of antimicrobial therapy daily for de-escalation,when appropriate(1B); infection source control with attention to the balance of risks and benefits of the chosen method within 12 hrs of diagnosis(1C);initial fluid resuscitation with crystalloid(1B)and consideration of the addition of albumin in patients who continue to require substantial amounts of crystalloid to maintain adequate mean arterial pressure(2C)and the avoidance of hetastarch formulations(1C); initial fluid challenge in patients with sepsis-induced tissue hypoperfusion and suspicion of hypovolemia to achieve a minimum of 30 mL/kg of crystalloids(more rapid administration and greater amounts of fluid may be needed in some patients)(1C); fluid challenge technique continued as long as hemodynamic improvement,as based on either dynamic or static variables(UG); norepinephrine as the first-choice vasopressor to maintain mean arterial pressure ≥ 65 mm Hg(1B); epinephrine when an additional agent is needed to maintain adequate blood pressure(2B); vasopressin(0.03 U/min)can be added to norepinephrine to either raise mean arterial pressure to target or to decrease norepinephrine dose but should not be used as the initial vasopressor(UG); dopamine is not recommended except in highly selected circumstances(2C);dobutamine infusion administered or added to vasopressor in the presence of a)myocardial dysfunction as suggested by elevated cardiac filling pressures and low cardiac output,or b)ongoing signs of hypoperfusion despite achieving adequate intravascular volume and adequate mean arterial pressure(1C); avoiding use of intravenous hydrocortisone in adult septic shock patients if adequate fluid resuscitation and vasopressor therapy are able to restore hemodynamic stability(2C); hemoglobin target of 7-9 g/dL in the absence of tissue hypoperfusion,ischemic coronary artery disease,or acute hemorrhage(1B); low tidal volume(1A)and limitation of inspiratory plateau pressure(1B)for acute respiratory distress syndrome(ARDS); application of at least a minimal amount of positive end-expiratory pressure(PEEP)in ARDS(1B); higher rather than lower level of PEEP for patients with sepsis-induced moderate or severe ARDS(2C); recruitment maneuvers in sepsis patients with severe refractory hypoxemia due to ARDS(2C); prone positioning in sepsis-induced ARDS patients with a Pao(2)/Fio(2)ratio of <= 100 mm Hg in facilities that have experience with such practices(2C); head-of-bed elevation in mechanically ventilated patients unless contraindicated(1B); a conservative fluid strategy for patients with established ARDS who do not have evidence of tissue hypoperfusion(1C); protocols for weaning and sedation(1A); minimizing use of either intermittent bolus sedation or continuous infusion sedation targeting specific titration endpoints(1B); avoidance of neuromuscular blockers if possible in the septic patient without ARDS(1C); a short course of neuromuscular blocker(no longer than 48 hrs)for patients with early ARDS and a Pao(2)/Fio(2)<150 mm Hg(2C);a protocolized approach to blood glucose management commencing insulin dosing when two consecutive blood glucose levels are > 180 mg/dL,targeting an upper blood glucose ≤ 180 mg/dL(1A); equivalency of continuous veno-venous hemofiltration or intermittent hemodialysis(2B); prophylaxis for deep vein thrombosis(1B); use of stress ulcer prophylaxis to prevent upper gastrointestinal bleeding in patients with bleeding risk factors(1B); oral or enteral(if necessary)feedings,as tolerated,rather than either complete fasting or provision of only intravenous glucose within the first 48 hrs after a diagnosis of severe sepsis/ septic shock(2C); and addressing goals of care,including treatment plans and end-of-life planning(as appropriate)(1B),as early as feasible,but within 72 hrs of intensive care unit admission(2C). Recommendations specific to pediatric severe sepsis include: therapy with face mask oxygen,high flow nasal cannula oxygen,or nasopharyngeal continuous PEEP in the presence of respiratory distress and hypoxemia(2C),use of physical examination therapeutic endpoints such as capillary refill(2C); for septic shock associated with hypovolemia,the use of crystalloids or albumin to deliver a bolus of 20 mL/kg of crystalloids(or albumin equivalent)over 5 to 10 mins(2C); more common use of inotropes and vasodilators for low cardiac output septic shock associated with elevated systemic vascular resistance(2C); and use of hydrocortisone only in children with suspected or proven "absolute" adrenal insufficiency(2C). Conclusions: Strong agreement existed among a large cohort of international experts regarding many level 1 recommendations for the best care of patients with severe sepsis. Although a significant number of aspects of care have relatively weak support,evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for this important group of critically ill patients.

Keywords: critically-ill patients; respiratory-distress-syndrome; intensive-care-unit; acute lung injury; randomized controlled-trial;acute-renal-failure; mechanically ventilated patients; combination antibiotic-therapy; clinical-practice guidelines; deep-vein thrombosis

来源出版物:Critical Care Medicine,2013,41(2): 580-637联系邮箱:Dellinger,RP; Dellinger-Phil@CooperHealth.edu

被引频次: 461

Global Strategy for the Diagnosis,Management,and Prevention of Chronic Obstructive Pulmonary Disease GOLD Executive Summary

Vestbo,J; Hurd,SS; Agusti,AG; et al.

Abstract: Chronic obstructive pulmonary disease(COPD)is a global health problem,and since 2001,the Global Initiative for Chronic Obstructive Lung Disease(GOLD)has published its strategy document for the diagnosis and management of COPD. This executive summary presents the main contents of the second 5-year revision of the GOLD document that has implemented some of the vast knowledge about COPD accumulated over the last years. Today,GOLD recommends that spirometry is required for the clinical diagnosis of COPD to avoid misdiagnosis and to ensure proper evaluation of severity of airflow limitation. The document highlights that the assessment of the patient with COPD should always include assessment of(1)symptoms,(2)severity of airflow limitation,(3)history of exacerbations,and(4)comorbidities. The first three points can be used to evaluate level of symptoms and risk of future exacerbations,and this is done in a way that splits patients with COPD into four categories-A,B,C,and D. Nonpharmacologic and pharmacologic management of COPD match this assessment in an evidence-based attempt to relieve symptoms and reduce risk of exacerbations. Identification and treatment of comorbidities must have high priority,and a separate section in the document addresses management of comorbidities as well as COPD in the presence of comorbidities. The revised document also contains a new section on exacerbations of COPD. The GOLD initiative will continue to bring COPD to the attention of all relevant shareholders and will hopefully.

Keywords: randomized controlled-trial; air-flow obstruction; positive-pressure ventilation; requiring mechanical ventilation; respiratory-tract infections; protected specimen brush; lung-function impairment; acute copd exacerbation; heart-failure; salmeterol/fluticasone propionate

来源出版物:American Journal of Respiratory and Critical Care Medicine,2013,187(4): 347-365

联系邮箱:Vestbo,J; jorgen.vestbo@manchester.ac.uk

被引频次: 208

Clinical Practice Guidelines for the Management of Pain,Agitation,and Delirium in Adult Patients in the Intensive Care Unit

Barr,J; Fraser,GL; Puntillo,K; et al.

Abstract: Objective: To revise the "Clinical Practice Guidelines for the Sustained Use of Sedatives and Analgesics in the Critically III Adult" published in Critical Care Medicine in 2002.

Methods: The American College of Critical Care Medicine assembled a 20-person,multidisciplinary,multi-institutional task force with expertise in guideline development,pain,agitation and sedation,delirium management,and associated outcomes in adult critically ill patients. The task force,divided into four subcommittees,collaborated over 6 yr in person,via teleconferences,and via electronic communication. Subcommittees were responsible for developing relevant clinical questions,using the Grading of Recommendations Assessment,Development and Evaluation method(http://www.gradeworkinggroup.org)to review,evaluate,and summarize the literature,and to develop clinical statements(descriptive)and recommendations(actionable). With the help of a professional librarian and Refworks(R)database software,they developed a Web-based electronic database of over 19000 references extracted from eight clinical search engines,related to pain and analgesia,agitation and sedation,delirium,and related clinical outcomes in adult ICU patients. The group also used psychometric analyses to evaluate and compare pain,agitation/sedation,and delirium assessment tools. All task force members were allowed to review the literature supporting each statement and recommendation and provided feedback to the subcommittees. Group consensus was achieved for all statements and recommendations using the nominal group technique and the modified Delphi method,with anonymous voting by all task force members using E-Survey(http://www.esurvey.com). All voting was completed in December 2010. Relevant studies published after this date and prior to publication of these guidelines were referenced in the text. The quality of evidence for each statement and recommendation was ranked as high(A),moderate(B),or low/very low(C). The strength of recommendations was ranked as strong(1)or weak(2),and either in favor of(+)or against(-)an intervention. A strong recommendation(either for or against)indicated that the intervention's desirable effects either clearly outweighed its undesirable effects(risks,burdens,and costs)or it did not. For all strong recommendations,the phrase "We recommend ..." is used throughout. A weak recommendation,either for or against an intervention,indicated that the tradeoff between desirable and undesirable effects was less clear. For all weak recommendations,the phrase "We suggest ..." is used throughout. In the absence of sufficient evidence,or when group consensus could not be achieved,no recommendation(0)was made. Consensus based on expert opinion was not used as a substitute for a lack of evidence. A consistent method for addressing potential conflict of interest was followed if task force members were coauthors of related research. The development of this guideline was independent of any industry funding.

Conclusion: These guidelines provide a roadmap for developing integrated,evidence-based,and patient-centered protocols for preventing and treating pain,agitation,and delirium in critically ill patients.

Keywords: critically-ill patients; mechanically ventilated patients; confusion assessment method; torsades-de-pointes; randomized controlled-trial; posttraumatic-stress-disorder; quality-of-life; respiratory-distress-syndrome; propofol infusion syndrome; long-term sedation

来源出版物:Critical Care Medicine,2013,41(1): 263-306联系邮箱:Barr,J; barrj@stanford.edu

被引频次: 92

Management of bleeding and coagulopathy following major trauma: an updated European guideline

Spahn,DR; Bouillon,B; Cerny,V; et al.

Abstract: Introduction: Evidence-based recommendations are needed to guide the acute management of the bleeding trauma patient. When these recommendations are implemented patient outcomes may be improved.

Methods: The multidisciplinary Task Force for Advanced Bleeding Care in Trauma was formed in 2005 with the aim of developing a guideline for the management of bleeding following severe injury. This document represents an updated version of the guideline published by the group in 2007 and updated in 2010. Recommendations were formulated using a nominal group process,the Grading of Recommendations Assessment,Development and Evaluation(GRADE)hierarchy of evidence and based on a systematic review of published literature.

Results: Key changes encompassed in this version of the guideline include new recommendations on the appropriate use of vasopressors and inotropic agents,and reflect an awareness of the growing number of patients in the population at large treated with antiplatelet agents and/or oral anticoagulants. The current guideline also includes recommendations and a discussion of thromboprophylactic strategies for all patients following traumatic injury. The most significant addition is a new section that discusses the need for every institution to develop,implement and adhere to an evidence-based clinical protocol to manage traumatically injured patients. The remaining recommendations have been re-evaluated and graded based on literature published since the last edition of the guideline. Consideration was also given to changes in clinical practice that have taken place during this time period as a result of both new evidence and changes in the general availability of relevant agents and technologies.

Conclusions: A comprehensive,multidisciplinary approach to trauma care and mechanisms with which to ensure that established protocols are consistently implemented will ensure a uniform and high standard of care across Europe and beyond.

Keywords: randomized-controlled-trial; prothrombin complex concentrate; fresh-frozen plasma; blunt abdominal-trauma; activated factor-vii; red-blood-cell; recombinant-factor-viia; respiratory-distress-syndrome; damage control resuscitation; controlled clinical-trial

来源出版物:Critical Care,2013,17(2): R76联系邮箱:Rossaint,R; RRossaint@ukaachen.de

被引频次: 77

An Official American Thoracic Society/European Respiratory Society Statement: Key Concepts and Advances in Pulmonary Rehabilitation

Spruit,MA; Singh,SJ; Garvey,C; et al.

Abstract: Background: Pulmonary rehabilitation is recognized as a core component of the management of individuals with chronic respiratory disease. Since the 2006 American Thoracic Society(ATS)/European Respiratory Society(ERS)Statement on Pulmonary Rehabilitation,there has been considerable growth in our knowledge of its efficacy and scope.

Purpose: The purpose of this Statement is to update the 2006 document,including a new definition of pulmonary rehabilitation and highlighting key concepts and major advances in the field.

Methods: A multidisciplinary committee of experts representing the ATS Pulmonary Rehabilitation Assembly and the ERS Scientific Group 01.02,"Rehabilitation and Chronic Care," determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant clinical and scientific expertise. The final content of this Statement was agreed on by all members.

Results: An updated definition of pulmonary rehabilitation is proposed. New data are presented on the science and application of pulmonary rehabilitation,including its effectiveness in acutely ill individuals with chronic obstructive pulmonary disease,and in individuals with other chronic respiratory diseases. The important role of pulmonary rehabilitation in chronic disease management is highlighted. In addition,the role of health behavior change in optimizing and maintaining benefits is discussed.

Conclusions: The considerable growth in the science and application of pulmonary rehabilitation since 2006 adds further support for its efficacy in a wide range of individuals with chronic respiratory disease.

Keywords: quality-of-life; randomized controlled-trial; air-flow limitation; critically-ill patients; chronic heart-failure; neuromuscular electrical-stimulation; intensive-care-unit; 6-minute walk distance; cell lung-cancer; functional exercise capacity

来源出版物:American Journal of Respiratory and Critical Care Medicine,2013,188(8): E13-E64

CRYSTALLOGRAPHY 结晶学

被引频次: 65

How good are my data and what is the resolution?

Evans,PR; Murshudov,GN

Abstract: Following integration of the observed diffraction spots,the process of 'data reduction' initially aims to determine the point-group symmetry of the data and the likely space group. This can be performed with the program POINTLESS. The scaling program then puts all the measurements on a common scale,averages measurements of symmetry-related reflections(using the symmetry determined previously)and produces many statistics that provide the first important measures of data quality. A new scaling program,AIMLESS,implements scaling models similar to those in SCALA but adds some additional analyses. From the analyses,a number of decisions can be made about the quality of the data and whether some measurements should be discarded. The effective 'resolution' of a data set is a difficult and possibly contentious question(particularly with referees of papers)and this is discussed in the light of tests comparing the data-processing statistics with trials of refinement against observed and simulated data,and automated model-building and comparison of maps calculated with different resolution limits. These trials show that adding weak high-resolution data beyond the commonly used limits may make some improvement and does no harm.

Keywords: x-ray data; data quality; r-factor; diffraction; refinement

来源出版物:Acta Crystallographica Section D-biological Crystallography,2013,69: 1204-1214

联系邮箱:Evans,PR; pre@mrc-lmb.cam.ac.uk

被引频次: 56

Synthesis of graphene-ZnO nanorod nanocomposites with improved photoactivity and anti-photocorrosion

Chen,Z; Zhang,N; Xu,YJ

Abstract: A series of graphene-ZnO(GR-ZnO)nanorod nanocomposites with different weight addition ratios of graphene(GR)have been prepared via a facile hydrothermal reaction of graphene oxide(GO)and ZnO nanorods. X-ray diffraction(XRD),UV-vis diffuse reflectance spectra(DRS),field-emission scanning electron microscopy(FE-SEM),electrochemical impedance spectroscopy(EIS),photoluminescence(PL)spectra,and electron spin resonance(ESR)spectra are employed to determine the properties of the samples. It is found that GR-ZnO nanorod nanocomposites with a proper addition amount of GR exhibit higher photocatalytic activity and improved anti-photocorrosion than ZnO nanorods toward liquid-phase degradation of dye under ultraviolet(UV)light irradiation. The improved photoactivity and anti-photocorrosion of GR-ZnO nanorods can be ascribed to the integrative synergistic effect of enhanced adsorption capacity,the prolonged lifetime of photogenerated electron-hole pairs and effective interfacial hybridization between GR and ZnO nanorods. This study also shows that graphene sheets act as electronic conductive channels to efficiently separate the photogenerated charge carriers from ZnO nanorods. It is hoped that our current work could promote increasing interest in designing the nanocomposites of one-dimensional(1D)semiconductor and two-dimensional(2D)graphene for different photocatalytic applications.

Keywords: photocatalytic h-2-production activity; one-dimensional nanostructures; volatile aromatic pollutant; high-performance;gas-phase; selective oxidation; ambient conditions; room-temperature; carbon nanotube; degradation

来源出版物:Crystengcomm,2013,15(15): 3022-3030联系邮箱:Chen,Z; yjxu@fzu.edu.cn

被引频次: 40

Syntheses,Structures,and Properties of a Series of Multidimensional Metal-Organic Polymers Based on 3,3',5,5 '-Biphenyltetracarboxylic Acid and N-Donor Ancillary Ligands

Zhang,XT; Fan,LM; Sun,Z; et al.

Abstract: Hydrothermal reactions of aromatic 3,3',5,5'-biphenyl-tetracarboxylic acid(H(4)bpt)and the transitional metal cations in the presence of rigid or flexible N-donor ancillary ligands afford nine novel coordination polymers,namely,[M(H(2)bpt)(Hpptp)](n)(M = Mn(1),Fe(2),Co(3),and Zn(4)),[Mn-2(bPt)(Hpptp)(2)](n)(5),{[Zn-3(Hbpt)-(bpt)(H2O)(2)][(4,4'-H(2)bmib)(0.5)]center dot H2O}(n)(6),{[Cu(bpt)(0.5)(4,4'-bimbp)]center dot H2O}(n)(7),{[Co(H(2)bpt)(2,7-dfo)center dot H2O}(n)(8),and {[Ni-2(bpt)(4,4'-bibp)(2.5)(H2O)]center dot 3(H2O)}(n)(9)(Hpptp = 2-(3-(4-(pyridin-4-yl)phenyl)-1H-1,2,4-triazol-5-yl)pyridine; 4,4'-bmib = 4,4'-bis(2-methylimidazol-1-yl)benzene; 4,4'-bimbp = 4,4'-bis(imidazol-1-ylmethyl)biphenyl; 2,7-dfo = 2,7-di(imidazo-1-ly)-9H-fluoren-9-one; 4,4'-bibp = 4,4'-bis(imidazol)-biphenyl). Their structures have been determined by single-crystal X-ray diffraction analyses,elemental analyses,IR spectra,powder X-ray diffraction(PXRD),and thermogravimetric(TG)analyses. Complexes 1-4 are isomorphism and feature a similar 2-fold interpenetrating 2D helical double layer,which is further extended via the interlayer pi center dot center dot center dot pi interactions into a 3D supramolecular structure. Complex 5 displays a pillared-layer 3D porous network with a(6(2).8)(2)(6(2).8(2).10(2))topology. Compound 6 shows an unprecedented 3D host-framework consisting of Zn-6 clusters and exhibits a novel 3D(5,5,5,6,9)-connected topological net with the Schlafli symbol of(4(10).6(5))(4(19).6(16).8)(4(6).6(4))(4(7).6(3))(2). The topology of 7 is an unprecedented binodal(4,4)-connected 3D network with the Schlafli symbol of(6(2).8(4))(4(2).8(2))(2). Complex 8 exhibits a 3D(6(6))structure with left- and right-handed helical chains arranged alternately. Complex 9 is a novel trinodal(4,4,5)-connected 3D framework with the Schlafli symbol of(6(4).8(2))(6(5).8)(6(8).8(2)). To the best of our knowledge,the 3D frameworks with(5,5,5,6,9)-connected net for 6,binodal(4,4)-connected for 7,and trinodal(4,4,5)-connected for 9 have never been documented to date. Moreover,the luminescent properties of 4 and 6 have been investigated.

Keywords: coordination polymers; rational synthesis; crystal-structures; spin-crossover; frameworks; complexes; network; adsorption;molecules; isomerism

来源出版物:Crystal Growth & Design,2013,13(2): 792-803联系邮箱:Zhang,XT; xiutangzhang@yahoo.com.cn

被引频次: 40

Four New Cd(II)Coordination Polymers with Mixed Multidentate N-Donors and Biphenyl-Based Polycarboxylate Ligands: Syntheses,Structures,and Photo luminescent Properties

Sun,D; Han,LL; Yuan,S; et al.

Abstract: Four new cadmium(II)coordination polymers(CPs),{[Cd(Hpptpd)(H(2)bptta)]center dot 8H(2)O}(n)(1),{[Cd-2(Hpptpd)(2)(bptta)(H2O)2] center dot 4H(2)O}(n)(2),{[Cd-2(pptpz)(bpta)(H2O)]center dot H2O}(n)(3),and {[Cd(Hpptpz)(bpba)]center dot 2H(2)O}(n)(4)(Hpptpd = 2-(3-(4-(pyridin-4-yl)phenyl)-1H-1,2,4-triazol-5-yl)pyridine,Hpptpz = 2-(3-(4-(pyridin-4-yl)phenyl)-1H-1,2,4-triazol-5-yl)pyrazine,H(4)bptta = 3,3',5,5'-biphenyltetracarboxylic acid,H(3)bpta = 3,4',5-biphenyltricarboxylic acid,H(2)bpba = 3,4'-biphenylbicarboxylic acid),were synthesized under hydrothermal conditions. The CPs were structurally characterized by single-crystal X-ray diffraction analyses and further characterized by infrared spectra(IR),elemental analyses,powder X-ray diffraction(PXRD),and thermogravimetric analyses(TGA). Complex 1 exhibits an unusual 2D + 2D -> 2D parallel interpenetrated 63-hcb network. The adjacent 2D networks are interdigitated with each other to form the resulting three-dimensional(3D)supramolecular architecture through the interbilayer pi center dot center dot center dot pi stacking between Hpptpd ligands and nonclassical C-H center dot center dot center dot O hydrogen bonds. Complex 2 is a one-dimensional(1D)molecular ladder along the a direction and further extended via hydrogen bonds into the 3D supramolecular framework. Complex 3 exhibits a novel complicated 3D(3,4,4,5)-connected framework with the Schlafli symbol of(4.6(5))(4.6(7).8(2))(6(3))(6(4).8(2)). Complex 4 manifests an intriguing layered structure with 5-connected cadmium atom as a unique node and can be simplified to an Archimedean(3(3).4(4).5(3))cem topology with triangular and rectangular circuits. The topology of 4 could be alternately simplified to a 3,4-connected binodal layer with a V2O5-type network. The thermal stabilities and photoluminescence behaviors of them were also discussed.

Keywords: metal-organic frameworks; hydrogen-bonded networks; crystal-structures; spin-crossover; supramolecular isomerism; single-crystal; electrical-conductivity; carboxylate ligands; molecular tectonics; magnetic-properties

来源出版物:Crystal Growth & Design,2013,13(1): 377-385联系邮箱:Sun,D; dsun@sdu.edu.cn

被引频次: 34

Facile synthesis of NiCo2O4nanorod arrays on Cu conductive substrates as superior anode materials for high-rate Li-ion batteries

Liu,J; Liu,CP; Wan,YL; et al.

Abstract: In this work,we report a mild and cost-effective solution method to directly grow Ni-substituted Co3O4(ternary NiCo2O4)nanorod arrays on Cu substrates. Electrochemical impedance spectroscopy(EIS)measurements show that the values of the electrolyte resistance Re and charge-transfer resistance R-ct of NiCo2O4are 6.8 and 63.5 Omega,respectively,which are significantly lower than those of binary Co3O4(10.4 and 122.4 Omega). This EIS characterization strongly confirms that the ternary NiCo2O4anode has much higher electrical conductivity than that of the binary Co3O4electrode materials,which should greatly enhance the lithium storage performances. Due to the well-aligned 1D nanorod microstructure and a higher electrical conductivity,these ternary NiCo2O4nanorod arrays manifest high specific capacity,excellent cycling stability(a high reversible capacity of about 830 mA h g-1was achieved after 30 cycles at 0.5 C)and high rate capability(787,695,512,254,127 mA h g-1at 1 C,2 C,6 C 50 C and 110 C,respectively).

Keywords: high-performance anode; cathode materials; nanowire arrays; metal-oxide; negative-electrode; lithium batteries; high-capacity;Co3O4; storage; spinel

来源出版物:Crystengcomm,2013,15(8): 1578-1585联系邮箱:Liu,J; jliu@xtu.edu.cn

DENTISTRY ORAL SURGERY MEDICINE 牙科,口腔外科医学

被引频次: 74

Statistical methodology in oral and dental research: Pitfalls and recommendations

Hannigan,A; Lynch,CD

Abstract: Objectives: This study describes the pitfalls for commonly used statistical techniques in dental research and gives some recom-mendations for avoiding them. It also explores the potential of some of the newer statistical techniques for dental research.

Methods: Each of the commonly used techniques e.g. descriptive statistics,correlation and regression,hypothesis tests(parametric and non-parametric)and survival analysis are explored with examples and recommendations for their use are provided. Common sources of error including those of study design,insufficient information,ignoring the impact of clustering and underuse of confidence intervals are outlined. The potential of statistical techniques such as multivariate survival models,generalized estimating equations and multilevel models are also explored.

Conclusions: Reviews of published dental research repeatedly identify statistical errors in the design,analysis and conclusions of the study. Educating researchers on common pitfalls and giving recommendations for avoiding them may help researchers to eliminate statistical errors. Developments in statistical methodology should be routinely monitored to ensure the most appropriate statistical methods are used in dental research.

Keywords: survival analysis; clinical-trial; health; errors; time

来源出版物:Journal of Dentistry,2013,41(5): 385-392联系邮箱:Hannigan,A; ailish.hannigan@ul.ie

被引频次: 40

Bruxism defined and graded: an international consensus

Lobbezoo,F; Ahlberg,J; Glaros,AG; et al.

Abstract: To date,there is no consensus about the definition and diagnostic grading of bruxism. A written consensus discussion was held among an international group of bruxism experts as to formulate a definition of bruxism and to suggest a grading system for its operationalisation. The expert group defined bruxism as a repetitive jaw-muscle activity characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible. Bruxism has two distinct circadian manifestations: it can occur during sleep(indicated as sleep bruxism)or during wakefulness(indicated as awake bruxism). For the operationalisation of this definition,the expert group proposes a diagnostic grading system of possible,probable and definite sleep or awake bruxism. The proposed definition and grading system are suggested for clinical and research purposes in all relevant dental and medical domains.

Keywords: sleep bruxism; awake bruxism; definition; diagnostic grading system

来源出版物:Journal of Oral Rehabilitation,2013,40(1): 2-4联系邮箱:Lobbezoo,F; f.lobbezoo@acta.nl

被引频次: 34

Global Burden of Oral Conditions in 1990-2010: A Systematic Analysis

Marcenes,W; Kassebaum,NJ; Bernabe,E; et al.

Abstract: The Global Burden of Disease(GBD)2010 Study produced comparable estimates of the burden of 291 diseases and injuries in 1990,2005,and 2010. This article reports on the global burden of untreated caries,severe periodontitis,and severe tooth loss in 2010 and compares those figures with new estimates for 1990. We used disability-adjusted life-years(DALYs)and years lived with disability(YLDs)metrics to quantify burden. Oral conditions affected 3.9 billion people,and untreated caries in permanent teeth was the most prevalent condition evaluated for the entire GBD 2010 Study(global prevalence of 35% for all ages combined). Oral conditions combined accounted for 15 million DALYs globally(1.9% of all YLDs; 0.6% of all DALYs),implying an average health loss of 224 years per 100,000 population. DALYs due to oral conditions increased 20.8% between 1990 and 2010,mainly due to population growth and aging. While DALYs due to severe periodontitis and untreated caries increased,those due to severe tooth loss decreased. DALYs differed by age groups and regions,but not by genders. The findings highlight the challenge in responding to the diversity of urgent oral health needs worldwide,particularly in developing communities.

Keywords: disease; disability; health; mortality; injuries; life

来源出版物:Journal of Dental Research,2013,92(7): 592-597联系邮箱:Marcenes,W; w.marcenes@qmul.ac.uk

被引频次: 32

Low etiologic fraction for high-risk human papillomavirus in oral cavity squamous cell carcinomas

Lingen,MW; Xiao,WH; Schmitt,A; et al.

Abstract: Background: Human papillomavirus(HPV)is a cause of oropharyngeal cancer,but a role for HPV in the etiology of oral cavity squamous cell carcinomas(OCSCC)remains uncertain.

Methods: We sought to estimate the etiologic fraction for HPV among consecutive,incident OCSCC diagnosed from 2005 to 2011 at four North American hospitals. DNA and RNA purified from paraffin-embedded tumors were considered evaluable if positive for DNA and mRNA control genes by quantitative PCR. Fifteen high-risk(HR)HPV types were detected in tumors by consensus PCR followed by type-specific HR-HPV E6/7 oncogene expression by quantitative reverse-transcriptase PCR. P16 expression was evaluated by immunohistochemistry(IHC). A study of 400 cases allowed for precision to estimate an etiologic fraction of as low as 0%(97.5% confidence interval,0%-0.92%).

Results: Of 409 evaluable OCSCC,24(5.9%,95% CI 3.6-8.2)were HR-HPV E6/7 expression positive; 3.7%(95% CI 1.8-5.5)for HPV16 and 2.2%(95% CI 0.8-3.6)for other HR-HPV types. HPV-positive tumors arose from throughout the oral cavity(floor of mouth [n = 9],anterior tongue [6],alveolar process [4],hard palate [3],gingiva [1] and lip [1])and were significantly associated with male gender,small tumor stage,poor tumor differentiation,and basaloid histopathology. P16 IHC had very good-to-excellent sensitivity(79.2%,95% CI 57.9-92.9),specificity(93.0%,95% CI 90.0-95.3),and negative-predictive value(98.6%,95% CI 96.8-99.6),but poor positive-predictive value(41.3%,95% CI 27.0-56.8)for HR-HPV E6/7 expression in OCSCC.

Conclusion: The etiologic fraction for HR-HPV in OCSCC was 5.9%. p16 IHC had poor positive predictive value for detection of HPV in these cancers.

Keywords: oropharyngeal cancer; united-states; neck-cancer; head; infection; association; prevalence; countries; type-16; tissue

来源出版物:Oral Oncology,2013,49(1): 1-8联系邮箱:Gillison,ML; maura.gillison@osumc.edu

被引频次: 31

Optimizing dentin bond durability: Control of collagen degradation by matrix metalloproteinases and cysteine cathepsins

Tjaderhane,L; Nascimento,FD; Breschi,L; et al.

Abstract: Objectives. Contemporary adhesives lose their bond strength to dentin regardless of the bonding system used. This loss relates to the hydrolysis of collagen matrix of the hybrid layers. The preservation of the collagen matrix integrity is a key issue in the attempts to improve the dentin bonding durability.

Methods. Dentin contains collagenolytic enzymes,matrix metalloproteinases(MMPs)and cysteine cathepsins,which are responsible for the hydrolytic degradation of collagen matrix in the bonded interface.

Results. The identities,roles and function of collagenolytic enzymes in mineralized dentin has been gathered only within last 15 years,but they have already been demonstrated to have an important role in dental hard tissue pathologies,including the degradation of the hybrid layer. Identifying responsible enzymes facilitates the development of new,more efficient methods to improve the stability of dentin-adhesive bond and durability of bond strength.

Significance. Understanding the nature and role of proteolytic degradation of dentin-adhesive interfaces has improved immensely and has practically grown to a scientific field of its own within only 10 years,holding excellent promise that stable resin-dentin bonds will be routinely available in a daily clinical setting already in a near future.

Keywords: gelatin-degrading metalloprotease; ph-induced inactivation; self-etching adhesives; human coronal dentin; human procathepsin-b; acid-etched dentin; in-vitro; tissue inhibitors; hybrid layer; extracellular-matrix

来源出版物:Dental Materials,2013,29(1): 116-135联系邮箱:Tjaderhane,L; leo.tjaderhane@oulu.fi

DERMATOLOGY 皮肤科

被引频次: 66

Global Epidemiology of Psoriasis: A Systematic Review of Incidence and Prevalence

Parisi,R; Symmons,DPM; Griffiths,CEM; et al.

Abstract: The worldwide incidence and prevalence of psoriasis is poorly understood. To better understand this,we performed a systematic review of published population-based studies on the incidence and prevalence of psoriasis. Three electronic databases were searched from their inception dates to July 2011. A total of 385 papers were critically appraised; 53 studies reported on the prevalence and incidence of psoriasis in the general population. The prevalence in children ranged from 0%(Taiwan)to 2.1%(Italy),and in adults it varied from 0.91%(United States)to 8.5%(Norway). In children,the incidence estimate reported(United States)was 40.8/100000 person-years. In adults,it varied from 78.9/100000 person-years(United States)to 230/100000 person-years(Italy). The data indicated that the occurrence of psoriasis varied according to age and geographic region,being more frequent in countries more distant from the equator. Prevalence estimates also varied in relation to demographic characteristics in that studies confined to adults reported higher estimates of psoriasis compared with those involving all age groups. Studies on the prevalence and incidence of psoriasis have contributed to a better understanding of the burden of the disease. However,further research is required to fill existing gaps in understanding the epidemiology of psoriasis and trends in incidence over time.

Keywords: quality-of-life; skin diseases; atopic-dermatitis; risk-factors; representative sample; population survey; clinical survey; united-kingdom; community; health

来源出版物:Journal of Investigative Dermatology,2013,133(2): 377-385

联系邮箱:Ashcroft,DM; Darren.Ashcroft@manchester.ac.uk

被引频次: 56

Efficacy and safety of secukinumab in the treatment of moderate-to-severe plaque psoriasis: a randomized,double-blind,placebo-controlled phase II dose-ranging study

Papp,KA; Langley,RG; Sigurgeirsson,B; et al.

Abstract: Background Conventional systemic therapies for plaque psoriasis have not fully met the needs of patients,and although current biologic treatments are generally well tolerated,concerns exist with respect to long-term safety. Interleukin(IL)-17A is believed to be an important effector cytokine in the pathogenesis of psoriasis and is produced by Th17 cells,a class of helper T cells that act outside the established Th1/Th2 paradigm for regulation of innate and adaptive immunity.

Objectives To assess the efficacy and safety of different doses of secukinumab,a fully human anti-IL-17A IgG1 kappa monoclonal antibody,in patients with moderate-to-severe plaque psoriasis.

Methods Patients(n=125)were randomized 1:1:1:1:1 to receive subcutaneous doses of placebo(n=22)or secukinumab [1×25 mg(n=29),3×25 mg(n=26),3×75 mg(n=21)or 3×150 mg(n=27)] at weeks 0,4 and 8. After the 12-week treatment period,patients entered a follow-up period of 24 weeks. The primary efficacy outcome was at least 75% improvement from baseline in the Psoriasis Area and Severity Index score(PASI 75); secondary outcomes included the Investigator's Global Assessment(IGA)and PASI 90 and 50 response rates.

Results After 12 weeks of treatment,secukinumab 3×150 mg and 3×75 mg resulted in significantly higher PASI 75 response rates vs. placebo(82% and 57% vs. 9%; P<0.001 and P=0.002,respectively). Higher PASI 75 response rates compared with placebo were maintained throughout the follow-up period with these dosages [week 36,26%(n=7)and 19%(n=4)vs. 4%(n=1),respectively],with a gradual decline of PASI 75 response over time after the dosing period. IGA response rates were significantly higher in the 3 x 150 mg group vs. placebo at week 12(48% vs. 9%; P =0 005)and were consistently higher for the 3 x 150 mg and 3×75 mg groups vs. placebo at all time points from week 4 onward. The PASI 90 response rate was significantly higher in the 3×150 mg group vs. placebo(52% vs. 5%)at week 12 and remained higher during the follow-up period. Secukinumab was well tolerated. Two cases of neutropenia(≤grade 2)were reported in the 3×150 mg cohort.

Conclusions Treatment with subcutaneous secukinumab 3×75 mg and 3×150 mg met the primary outcome of PASI 75 response achievement after 12 weeks,demonstrating efficacy in moderate-to-severe psoriasis.

Keywords: cells; inflammation; antibody; distinct; therapy; lineage

来源出版物:British Journal of Dermatology,2013,168(2): 412-421联系邮箱:Papp,KA; kapapp@probitymedical.com

被引频次: 40

Secukinumab induction and maintenance therapy in moderate-to-severe plaque psoriasis: a randomized,double-blind,placebo-controlled,phase II regimen-finding study

Rich,P; Sigurgeirsson,B; Thaci,D; et al.

Abstract: Background Interleukin(IL)-17A has major proinflammatory activity in psoriatic lesional skin.

Objectives To assess the efficacy and safety of secukinumab,a fully human IgG1 kappa monoclonal anti-IL-17A antibody,in moderate-to-severe plaque psoriasis in a phase II regimen-finding study.

Methods A total of 404 patients were randomized to subcutaneous placebo(n = 67)or one of three secukinumab 150 mg induction regimens: single(week 0; n = 66),early(weeks 0,1,2,4; n =133)and monthly(weeks 0,4,8; n= 138 patients). The primary outcome was≥75% improvement from baseline Psoriasis Area and Severity Index score(PASI 75)at week 12. PASI 75 responders from active treatment arms at week 12 were rerandomized to either a fixed-interval(secukinumab 150 mg at weeks 12 and 24; n=65)or a treatment-at-start-of-relapse maintenance regimen(secukinumab 150 mg at visits at which a start of relapse was observed; n=67).

Results At week 12,early and monthly induction regimens resulted in higher PASI 75 response rates vs. placebo(54.5% and 42.0% vs. 1.5%; P <0.001 for both). Among PASI 75 responders at week 12 entering the maintenance period,PASI 75 and PASI 90 achievement at least once from week 20 to week 28 was superior with the fixed-interval regimen [85%(n=55)and 58%(n=38),respectively] vs. the start-of-relapse regimen [67%(n=45),P = 0 020,and 21%(n=14),respectively]. Fifteen weeks after last study drug administration,<10% of patients in the fixed-interval and start-of-relapse groups experienced a start of relapse. No immunogenicity was observed,and no injection-site reactions were reported. Reported cases of neutropenia were mild-to-moderate(≤grade 2); none was associated with clinically significant adverse events or resulted in study discontinuation. Due to the brief duration of the safety assessment,no firm conclusions can be drawn regarding long-term safety.

Conclusions Secukinumab shows efficacy for induction and maintenance treatment of moderate-to-severe plaque psoriasis.

Keywords: monoclonal-antibody; cells; interleukin-17; trial; gamma; keratinocytes; pathogenesis; inflammation; mechanisms; distinct

来源出版物:British Journal of Dermatology,2013,168(2): 402-411联系邮箱:Rich,P; rich@ohsu.org

被引频次: 35

Efinaconazole 10% solution in the treatment of toenail onychomycosis: Two phase III multicenter,randomized,double-blind studies

Elewski,BE; Rich,P; Pollak,R; et al.

Abstract: Background: Onychomycosis is a common nail infection,often resulting in nail plate damage and deformity. Topical lacquer treatments have negligible efficacy. Oral treatments,although more efficacious,are limited by drug interactions and potential hepatotoxicity.

Objective: We investigated the safety and efficacy of efinaconazole 10% solution(efinaconazole),the first triazole antifungal developed for distal lateral subungual onychomycosis.

Methods: Two identical,multicenter,randomized,double-blind,vehicle-controlled studies were conducted in patients with toenail distal lateral subungual onychomycosis(20%-50% clinical involvement [study 1: N=870,study 2: N =785]). Patients were randomized(3: 1)to efinaconazole or vehicle,once daily for 48 weeks,with 4-week posttreatment follow-up. Debridement was not performed. The primary end point was complete cure rate(0% clinical involvement of target toenail,and both negative potassium hydroxide examination and fungal culture)at week 52.

Results: Mycologic cure rates were significantly greater with efinaconazole(study 1: 55.2%,study 2: 53.4%)compared with vehicle(P<0.001). The primary end point,complete cure,was also significantly greater for efinaconazole(study 1: 17.8% vs 3.3%,study 2: 15.2% vs 5.5%,P<0.001). Treatment success(percent affected target toenail [0%-≤10%])for efinaconazole ranged from 21.3% to 44.8% in study 1 and from 17.9% to 40.2% in study 2,compared with 5.6% to 16.8% and 7.0% to 15.4%,respectively,with vehicle. Adverse events associated with efinaconazole were local site reactions(2%)and clinically similar to vehicle.

Limitations: A period of 52 weeks may be too brief to evaluate a clinical cure in onychomycosis.

Conclusions: Once daily topical efinaconazole appears to be a viable alternative to oral treatment options for onychomycosis.

Keywords: quality-of-life; combination therapy; treatment options; nail lacquer; terbinafine; drugs; permeability; infections; amorolfine;efficacy

来源出版物:Journal of The American Academy of Dermatology,2013,68(4): 600-608联系邮箱:Elewski,BE; beelewski@aol.com

被引频次: 35

The Emerging Role of IL-17 in the Pathogenesis of Psoriasis: Preclinical and Clinical Findings

Martin,DA; Towne,JE; Kricorian,G; et al.

Abstract: Although the histological changes seen in psoriasis have long been well characterized,the underlying cellular and molecular mechanisms have only begun to be elucidated over the past 20 years. Proinflammatory factors such as tumor necrosis factor(TNF)-alpha have a central role in psoriasis pathogenesis,and many T-helper 1(Th1)cytokines and messenger RNAs are elevated in psoriatic lesions. IL-17A,IL-17F,and other Th17 cell-derived cytokines have been shown in murine models to induce features that mimic human psoriasis. This review focuses on the emerging biology of the IL-17 cytokine family in psoriasis,and on the molecular and genetic information gained from animal models and human clinical studies that confirm IL-17 as a crucial proinflammatory cytokine in psoriasis. Expression of IL-17A,IL-17C,and IL-17F is strikingly increased in psoriatic lesions,and successful therapy is associated with restoration of the expression of a wide range of genes(including effector molecules downstream of IL-17 such as cytokines,chemokines,and antimicrobial peptides)to near-normal levels. Therapeutic agents in development that target IL-17 are discussed,and an emerging model of the key role of IL-17 in the pathogenesis of psoriasis is presented.

Keywords: genome-wide association; systemic-lupus-erythematosus; anti-interleukin-17 monoclonal-antibody; chronic mucocutaneous candidiasis; crohns-disease susceptibility; regulatory t-cells; human t(h)17 cells; hyper-ige syndrome; amg 827 leads; rheumatoid-arthritis

来源出版物:Journal of Investigative Dermatology,2013,133(1): 17-26联系邮箱:Martin,DA; davidm02@amgen.com

DEVELOPMENTAL BIOLOGY 发育生物学

被引频次: 87

The Hippo pathway: regulators and regulations

Yu,FX; Guan,KL

Abstract: Control of cell number is crucial in animal development and tissue homeostasis,and its dysregulation may result in tumor formation or organ degeneration. The Hippo pathway in both Drosophila and mammals regulates cell number by modulating cell proliferation,cell death,and cell differentiation. Recently,numerous upstream components involved in the Hippo pathway have been identified,such as cell polarity,mechanotransduction,and G-protein-coupled receptor(GPCR)signaling. Actin cytoskeleton or cellular tension appears to be the master mediator that integrates and transmits upstream signals to the core Hippo signaling cascade. Here,we review regulatory mechanisms of the Hippo pathway and discuss potential implications involved in different physiological and pathological conditions.

Keywords: tumor-suppressor pathway; yes-associated protein; organ size control; stem-cell proliferation; cultured osteoblastic cells; domain-containing protein; controls tissue-growth; breast-cancer cells; scf-beta-trcp; signaling-pathway

来源出版物:Genes & Development,2013,27(4): 355-371联系邮箱:Guan,KL; kuguan@ucsd.edu

被引频次: 80

Adaptive thermogenesis in adipocytes: Is beige the new brown?

Wu,J; Cohen,P; Spiegelman,BM

Abstract: One of the most promising areas in the therapeutics for metabolic diseases centers around activation of the pathways of energy expenditure. Brown adipose tissue is a particularly appealing target for increasing energy expenditure,given its amazing capacity to transform chemical energy into heat. In addition to classical brown adipose tissue,the last few years have seen great advances in our understanding of inducible thermogenic adipose tissue,also referred to as beige fat. A deeper understanding of the molecular processes involved in the development and function of these cell types may lead to new therapeutics for obesity,diabetes,and other metabolic diseases.

Keywords: white adipose-tissue; diet-induced obesity; activated receptor-gamma; mitochondrial uncoupling-protein; growth-factor-beta;energy-expenditure; skeletal-muscle; insulin-resistance; ppar-gamma; gene-expression

来源出版物:Genes & Development,2013,27(3): 234-250联系邮箱:Spiegelman,BM; bruce_spiegelman@dfci.harvard.edu

被引频次: 78

The Tissue-Specific IncRNA Fendrr Is an Essential Regulator of Heart and Body Wall Development in the Mouse

Grote,P; Wittler,L; Hendrix,D; et al.

Abstract: The histone-modifying complexes PRC2 and TrxG/MLL play pivotal roles in determining the activation state of genes controlling pluripotency,lineage commitment,and cell differentiation. Long noncoding RNAs(IncRNAs)can bind to either complex,and some have been shown to act as modulators of PRC2 or TrxG/MLL activity. Here we show that the lateral mesoderm-specific IncRNA Fendrr is essential for proper heart and body wall development in the mouse. Embryos lacking Fendrr displayed upregulation of several transcription factors controlling lateral plate or cardiac mesoderm differentiation,accompanied by a drastic reduction in PRC2 occupancy along with decreased H3K27 trimethylation and/or an increase in H3K4 trimethylation at their promoters. Fendrr binds to both the PRC2 and TrxG/MLL complexes,suggesting that it acts as modulator of chromatin signatures that define gene activity. Thus,we identified an IncRNA that plays an essential role in the regulatory networks controlling the fate of lateral mesoderm derivatives.

Keywords: long noncoding rna; gene-expression; polycomb; chromatin; proteins; differentiation; mesoderm; morphogenesis; dissection;complexes

来源出版物:Developmental Cell,2013,24(2): 206-214联系邮箱:Herrmann,BG; herrmann@molgen.mpg.de

被引频次: 61

Combined Deficiency of Tet1 and Tet2 Causes Epigenetic Abnormalities but Is Compatible with Postnatal Development

Dawlaty,MM; Breiling,A; Le,T; et al.

Abstract: Tet enzymes(Tet1/2/3)convert 5-methylcytosine(5mC)to 5-hydroxymethylcytosine(5hmC)in various embryonic and adult tissues. Mice mutant for either Tet1 or Tet2 are viable,raising the question of whether these enzymes have overlapping roles in development. Here we have generated Tet1 and Tet2 double-knockout(DKO)embryonic stem cells(ESCs)and mice. DKO ESCs remained pluripotent but were depleted of 5hmC and caused developmental defects in chimeric embryos. While a fraction of double-mutant embryos exhibited midgestation abnormalities with perinatal lethality,viable and overtly normal Tet1/Tet2-deficient mice were also obtained. DKO mice had reduced 5hmC and increased 5mC levels and abnormal methylation at various imprinted loci. Nevertheless,animals of both sexes were fertile,with females having smaller ovaries and reduced fertility. Our data show that loss of both enzymes is compatible with development but promotes hypermethylation and compromises imprinting. The data also suggest a significant contribution of Tet3 to hydroxylation of 5mC during development.

Keywords: embryonic stem-cells; active dna demethylation; mammalian dna; self-renewal; 5-hydroxymethylcytosine; mouse; genes;5-methylcytosine; proteins; genome

来源出版物:Developmental Cell,2013,24(3): 310-323联系邮箱:Lyko,F; f.lyko@dkfz-heidelberg.de

被引频次: 49

Piwi induces piRNA-guided transcriptional silencing and establishment of a repressive chromatin state

Le Thomas,A; Rogers,AK; Webster,A; et al.

Abstract: In the metazoan germline,piwi proteins and associated piwi-interacting RNAs(piRNAs)provide a defense system against theexpression of transposable elements. In the cytoplasm,piRNA sequences guide piwi complexes to destroy complementary transposon transcripts by endonucleolytic cleavage. However,some piwi family members are nuclear,raising the possibility of alternative pathways for piRNA-mediated regulation of gene expression. We found that Drosophila Piwi is recruited to chromatin,colocalizing with RNA polymerase II(Pol II)on polytene chromosomes. Knockdown of Piwi in the germline increases expression of transposable elements that are targeted by piRNAs,whereas protein-coding genes remain largely unaffected. Derepression of transposons upon Piwi depletion correlates with increased occupancy of Pol II on their promoters. Expression of piRNAs that target a reporter construct results in a decrease in Pol II occupancy and an increase in repressive H3K9me3 marks and heterochromatin protein 1(HP1)on the reporter locus. Our results indicate that Piwi identifies targets complementary to the associated piRNA and induces transcriptional repression by establishing a repressive chromatin state when correct targets are found.

Keywords: drosophila somatic-cells; large gene lists; DNA methylation; argonaute proteins; in-vivo; heterochromatin formation; lysine-9 methylation; epigenetic memory; messenger-rnas; c. elegans

来源出版物:Genes & Development,2013,27(4): 390-399联系邮箱:Aravin,AA; aravin@caltech.edu

ECOLOGY 生态学

被引频次: 150

Hybridization and speciation

Abbott,R; Albach,D; Ansell,S; et al.

Abstract: Hybridization has many and varied impacts on the process of speciation. Hybridization may slow or reverse differentiation by allowing gene flow and recombination. It may accelerate speciation via adaptive introgression or cause near-instantaneous speciation by allopolyploidization. It may have multiple effects at different stages and in different spatial contexts within a single speciation event. We offer a perspective on the context and evolutionary significance of hybridization during speciation,highlighting issues of current interest and debate. In secondary contact zones,it is uncertain if barriers to gene flow will be strengthened or broken down due to recombination and gene flow. Theory and empirical evidence suggest the latter is more likely,except within and around strongly selected genomic regions. Hybridization may contribute to speciation through the formation of new hybrid taxa,whereas introgression of a few loci may promote adaptive divergence and so facilitate speciation. Gene regulatory networks,epigenetic effects and the evolution of selfish genetic material in the genome suggest that the DobzhanskyMuller model of hybrid incompatibilities requires a broader interpretation. Finally,although the incidence of reinforcement remains uncertain,this and other interactions in areas of sympatry may have knock-on effects on speciation both within and outside regions of hybridization.

Keywords: homoploid hybrid speciation; reproductive character displacement; adaptive population divergence; senecio-squalidus asteraceae; adjacent plant-populations; gene-expression divergence; natural-selection; local adaptation; sexual selection; genome duplication

来源出版物:Journal of Evolutionary Biology,2013,26(2): 229-246联系邮箱:Butlin,RK; r.k.butlin@sheffield.ac.uk

被引频次: 142

A general and simple method for obtaining R2from generalized linear mixed-effects models

Nakagawa,S; Schielzeth,H

Abstract: The use of both linear and generalized linear mixed-effects models(LMMs and GLMMs)has become popular not only in social and medical sciences,but also in biological sciences,especially in the field of ecology and evolution. Information criteria,such as Akaike Information Criterion(AIC),are usually presented as model comparison tools for mixed-effects models. The presentation of variance explained'(R2)as a relevant summarizing statistic of mixed-effects models,however,is rare,even though R2is routinely reported for linear models(LMs)and also generalized linear models(GLMs). R2has the extremely useful property of providing an absolute value for the goodness-of-fit of a model,which cannot be given by the information criteria. As a summary statistic that describes the amount of variance explained,R2can also be a quantity of biological interest. One reason for the under-appreciation of R2for mixed-effects models lies in the fact that R2can be defined in a number of ways. Furthermore,most definitions of R2for mixed-effects have theoretical problems(e.g. decreased or negative R2values in larger models)and/or their use is hindered by practical difficulties(e.g. implementation). Here,we make a case for the importance of reporting R2for mixed-effects models. We first provide the common definitions of R2for LMs and GLMs and discuss the key problems associated with calculating R2for mixed-effects models. We then recommend a general and simple method for calculating two types of R2(marginal and conditional R2)for both LMMs and GLMMs,which are less susceptible to common problems. This method is illustrated by examples and can be widely employed by researchers in any fields of research,regardless of software packages used for fitting mixed-effects models. The proposed method has the potential to facilitate the presentation of R2for a wide range of circumstances.

Keywords: goodness-of-fit; brief conceptual tutorial; regression-models; practical guide; social epidemiology; multilevel analysis; bayesian measures; coefficients; R2; biologists

来源出版物:Methods in Ecology and Evolution,2013,4(2): 133-142联系邮箱:Nakagawa,S; shinichi.nakagawa@otago.ac.nz

被引频次: 100

Collinearity: a review of methods to deal with it and a simulation study evaluating their performance

Dormann,CF; Elith,J; Bacher,S; et al.

Abstract: Collinearity refers to the non independence of predictor variables,usually in a regression-type analysis. It is a common feature of any descriptive ecological data set and can be a problem for parameter estimation because it inflates the variance of regression parameters and hence potentially leads to the wrong identification of relevant predictors in a statistical model. Collinearity is a severe problem when a model is trained on data from one region or time,and predicted to another with a different or unknown structure of collinearity. To demonstrate the reach of the problem of collinearity in ecology,we show how relationships among predictors differ between biomes,change over spatial scales and through time. Across disciplines,different approaches to addressing collinearity problems have been developed,ranging from clustering of predictors,threshold-based pre-selection,through latent variable methods,to shrinkage and regularisation. Using simulated data with five predictor-response relationships of increasing complexity and eight levels of collinearity we compared ways to address collinearity with standard multiple regression and machine-learning approaches. We assessed the performance of each approach by testing its impact on prediction to new data. In the extreme,we tested whether the methods were able to identify the true underlying relationship in a training dataset with strong collinearity by evaluating its performance on a test dataset without any collinearity. We found that methods specifically designed for collinearity,such as latent variable methods and tree based models,did not outperform the traditional GLM and threshold-based pre-selection. Our results highlight the value of GLM in combination with penalised methods(particularly ridge)and threshold-based pre-selection when omitted variables are considered in the final interpretation. However,all approaches tested yielded degraded predictions under change in collinearity structure and the folk lore'-thresholds of correlation coefficients between predictor variables of |r| >0.7 was an appropriate indicator for when collinearity begins to severely distort model estimation and subsequent prediction. The use of ecological understanding of the system in pre-analysis variable selection and the choice of the least sensitive statistical approaches reduce the problems of collinearity,but cannot ultimately solve them.

Keywords: latent root regression; principal component regression; sliced inverse regression; partial least-squares; dimension reduction;multiple-regression; climate-change; logistic-regression; ridge-regression; ecological data

来源出版物:Ecography,2013,36(1): 27-46联系邮箱:Dormann,CF; carsten.dormann@biom.uni-freiburg.de

被引频次: 97

Impacts of biological invasions: what's what and the way forward

Simberloff,D; Martin,JL; Genovesi,P; et al.

Abstract: Study of the impacts of biological invasions,a pervasive component of global change,has generated remarkable understanding of the mechanisms and consequences of the spread of introduced populations. The growing field of invasion science,poised at a crossroads where ecology,social sciences,resource management,and public perception meet,is increasingly exposed to critical scrutiny from several perspectives. Although the rate of biological invasions,elucidation of their consequences,and knowledge about mitigation are growing rapidly,the very need for invasion science is disputed. Here,we highlight recent progress in understanding invasion impacts and management,and discuss the challenges that the discipline faces in its science and interactions with society.

Keywords: exotic plant invasions; fresh-water fish; introduced predators; ecosystem responses; ecological impacts; biodiversity; forests;communities; islands; rats

来源出版物:Trends in Ecology & Evolution,2013,28(1): 58-66联系邮箱:Simberloff,D; dsimberloff@utk.edu

被引频次: 86

Impacts of ocean acidification on marine organisms: quantifying sensitivities and interaction with warming

Kroeker,KJ; Kordas,RL; Crim,R; et al.

Abstract: Ocean acidification represents a threat to marine species worldwide,and forecasting the ecological impacts of acidification is a high priority for science,management,and policy. As research on the topic expands at an exponential rate,a comprehensive understanding of the variability in organisms' responses and corresponding levels of certainty is necessary to forecast the ecological effects. Here,we perform the most comprehensive meta-analysis to date by synthesizing the results of 228 studies examining biological responses to ocean acidification. The results reveal decreased survival,calcification,growth,development and abundance in response to acidification when the broad range of marine organisms is pooled together. However,the magnitude of these responses varies among taxonomic groups,suggesting there is some predictable trait-based variation in sensitivity,despite the investigation of approximately 100 new species in recent research. The results also reveal an enhanced sensitivity of mollusk larvae,but suggest that an enhanced sensitivity of early life history stages is not universal across all taxonomic groups. In addition,the variability in species' responses is enhanced when they are exposed to acidification in multi-species assemblages,suggesting that it is important to consider indirect effects and exercise caution when forecasting abundance patterns from single-species laboratory experiments. Furthermore,the results suggest that other factors,such as nutritional status or source population,could cause substantial variation in organisms' responses. Last,the results highlight a trend towards enhanced sensitivityto acidification when taxa are concurrently exposed to elevated seawater temperature.

Keywords: climate-change; coral; metaanalysis; carbon; temperature; responses; exposure; fish; pH; calcification

来源出版物:Global Change Biology,2013,19(6): 1884-1896联系邮箱:Kroeker,KJ; kjkroeker@ucdavis.edu

ELECTROCHEMISTRY 电化学

被引频次: 105

Liquid electrolyte lithium/sulfur battery: Fundamental chemistry,problems,and solutions

Zhang,SS

Abstract: Lithium/sulfur(Li/S)battery has a 3-5 fold higher theoretical energy density than state-of-art lithium-ion batteries,and research has been ongoing for more than three decades. However,the commercialization of Li/S battery still cannot be realized due to many problematic issues,including short cycle life,low cycling efficiency,poor safety and a high self-discharge rate. All these issues are related to the dissolution of lithium polysulfide(PS),the series of sulfur reduction intermediates,in liquid electrolyte and to resulting parasitic reactions with the lithium anode and electrolyte components. On the other hand,the dissolution of PS is essential for the performance of a Li/S cell. Without dissolution of PS,the Li/S cell cannot operate progressively due to the non-conductive nature of elemental sulfur and its reduction products. In this review article,we start with the fundamental chemistry of elemental sulfur in order to discuss the problems and solutions of liquid electrolyte Li/S battery.

Keywords: composite cathode materials; glycol)dimethyl ether; high-capacity density; Li/S battery; sulfur batteries; electrochemical properties; carbon nanotubes; enhanced cyclability; graphene oxide; ion batteries

来源出版物:Journal of Power Sources,2013,231: 153-162联系邮箱:Zhang,SS; shengshui.zhang.civ@mail.mil

被引频次: 82

A review on the key issues for lithium-ion battery management in electric vehicles

Lu,LG; Han,XB; Li,JQ; et al.

Abstract: Compared with other commonly used batteries,lithium-ion batteries are featured by high energy density,high power density,long service life and environmental friendliness and thus have found wide application in the area of consumer electronics. However,lithium-ion batteries for vehicles have high capacity and large serial-parallel numbers,which,coupled with such problems as safety,durability,uniformity and cost,imposes limitations on the wide application of lithium-ion batteries in the vehicle. The narrow area in which lithium-ion batteries operate with safety and reliability necessitates the effective control and management of battery management system. This present paper,through the analysis of literature and in combination with our practical experience,gives a brief introduction to the composition of the battery management system(BMS)and its key issues such as battery cell voltage measurement,battery states estimation,battery uniformity and equalization,battery fault diagnosis and so on,in the hope of providing some inspirations to the design and research of the battery management system.

Keywords: state-of-charge; subspace parameter-estimation; open-circuit-voltage; capacity-loss prediction; self-discharge behavior; rapid-transit vehicle; nickel metal hydride; lead-acid-batteries; life-prediction; cycle-life

来源出版物:Journal of Power Sources,2013,226: 272-288联系邮箱:Ouyang,MG; ouymg@tsinghua.edu.cn

被引频次: 75

Biomimetic sensor for certain catecholamines employing copper(II)complex and silver nanoparticle modified glassy carbon paste electrode

Sanghavi,BJ; Mobin,SM; Mathur,P; et al.

Abstract: A dimeric Cu(II)complex [Cu(mu(2)-heP)(heP-H)]2 center dot 2ClO(4)(1)containing bidentate(hep-H=2-(2- hydroxyethyl)pyridine)ligand was synthesized and characterized by single crystal X-ray diffraction studies. Each Cu-ion in 1 is in a distorted square pyramidal geometry. Further 1 along with silver nanoparticles(SNPs)have been used as modifier in the construction of a biomimetic sensor(1-SNP-GCPE)for determining certain catecholamines viz.,dopamine(DA),levodopa(L-Dopa),epinephrine(EP)and norepinephrine(NE)using cyclic voltammetry,chronocoulometry,electrochemical impedance spectroscopy and adsorptive stripping square wave voltammetry(AdSSWV). Finally,the catalytic properties of the sensor were characterized by chronoamperometry. Employing AdSSWV,the calibration curves showed linear response ranging between 10-6and 10-9M for all the four analytes with detection limits(S/N=3)of 8.52 × 10-10M,2.41 × 10-9M,3.96 × 10-1M and 3.54 × 10-1M for DA,L-Dopa,EP and NE respectively. The lifetime of the biomimetic sensor was 3 months at room temperature. The prepared modified electrode shows several advantages such as simple preparation method,high sensitivity,high stability,ease of preparation and regeneration of the electrode surface by simple polishing along with excellent reproducibility. The method has been applied for the selective and precise analysis of DA,L-Dopa,EP and NE in pharmaceutical formulations,urine and blood serum samples.

Keywords: potentiometric stripping analysis; hydrophilic interaction chromatography; chemically-modified electrodes; ascorbic-acid;uric-acid; voltammetric determination; electrochemical sensor; folic-acid; capillary-electrophoresis; chloride complex

来源出版物:Biosensors & Bioelectronics,2013,39(1): 124-132联系邮箱:Srivastava,AK; aksrivastava@chem.mu.ac.in

被引频次: 67

A comprehensive review on PEM water electrolysis

Carmo,M; Fritz,DL; Merge,J; et al.

Abstract: Hydrogen is often considered the best means by which to store energy coming from renewable and intermittent power sources. With the growing capacity of localized renewable energy sources surpassing the gigawatt range,a storage system of equal magnitude is required. PEM electrolysis provides a sustainable solution for the production of hydrogen,and is well suited to couple with energy sources such as wind and solar. However,due to low demand in electrolytic hydrogen in the last century,little research has been done on PEM electrolysis with many challenges still unexplored. The ever increasing desire for green energy has rekindled the interest on PEM electrolysis,thus the compilation and recovery of past research and developments is important and necessary. In this review,PEM water electrolysis is comprehensively highlighted and discussed. The challenges new and old related to electrocatalysts,solid electrolyte,current collectors,separator plates and modeling efforts will also be addressed. The main message is to clearly set the state-of-the-art for the PEM electrolysis technology,be insightful of the research that is already done and the challenges that still exist. This information will provide several future research directions and a road map in order to aid scientists in establishing PEM electrolysis as a commercially viable hydrogen production solution.

Keywords: solid polymer-electrolyte; oxygen evolution reaction; membrane fuel-cells; high-temperature electrolysis; gas-diffusion layer;ruthenium oxide catalyst; bulk metallic-glass; hydrogen evolution; electrochemical-behavior; ad-atoms

来源出版物:International Journal of Hydrogen Energy,2013,38(12): 4901-4934联系邮箱:Carmo,M; marcelocarmo1@gmail.com

被引频次: 56

Cathodic deposition of Ni(OH)2and Co(OH)2for asymmetric supercapacitors: Importance of the electrochemical reversibility of redox couples

Hu,CC; Chen,JC; Chang,KH

Abstract: This work demonstrates the influences of electrochemical reversibility of the pseudocapacitive materials on the performances of an asymmetric supercapacitor consisting of a pseudocapacitive cathode and an anode of the double-layer type. Thanks for the simple,one-step,cathodic deposition of nickel and cobalt hydroxide(denoted as Ni(OH)2and Co(OH)2,respectively)films from their chloride precursor in aqueous media with the addition of 40 mM NO3-as the OH-donating agent. The specific capacitances of Ni(OH)2and Co(OH)2films(ca. 0.4 mg cm-2)deposited at 1.0 mA cm-2for 1000 s are equal to 2217 and 549 F g-1,respectively while the electrochemical reversibility of Co(OH)2is better than that of Ni(OH)2based on peak potential difference and symmetry of charge/discharge curves. The Co(OH)2-graphene asymmetric supercapacitor shows higher capacitance retention and higher energy efficiency of charge-discharge than the Ni(OH)2-graphene system although the latter system exhibits higher energy and power densities than the former one. The microstructures of as-deposited Ni(OH)2and Co(OH)2films have been examined by scanning electron microscopic(SEM),transmission electron microscopic(TEM),and X-ray diffraction(XRD)analyses.

Keywords: capacitors; hydroxide; batteries; oxides; film

来源出版物:Journal of Power Sources,2013,221: 128-133联系邮箱:Hu,CC; cchu@che.nthu.edu.tw

EMERGENCY MEDICINE 急救医学

被引频次: 28

Synthetic Cannabinoid Intoxication: A Case Series And Review

Harris,CR; Brown,A

Abstract: Background: Synthetic cannabinoid receptor agonists are becoming increasingly popular with adolescents as an abused substance. Chronic use of these drugs can lead to addiction syndrome and withdrawal symptoms similar to cannabis abuse. Due to their potential health risk,several countries have banned these substances. Objectives: To report the clinical presentation and legislation status of synthetic cannabinoids in "Spice'' products and alert the health care community about the identification and risk assessment problems of these compounds. Case Reports: We retrospectively reviewed cases presenting to our Emergency Department(ED)during a 3-month period with chief complaints of Spice drug use before arrival. Six cases presented to our ED after using Spice drugs. Two patients were admitted after reporting seizures. All but one presented with tachycardia. Two patients had hallucinations. The average length of ED observation was 2.8 h. No patient with seizures had recurrent episodes. Conclusion: Spice drugs can cause potentially serious health care conditions that necessitate ED evaluation. Most cases can be discharged from the ED after a period of observation. Legal issues surrounding these drugs are yet to be finalized in the United States.

Keywords: cb2 receptor; pharmacology; ligands; hippocampus; jwh-018

来源出版物:Journal of Emergency Medicine,2013,44(2): 360-366联系邮箱:Harris,CR;

被引频次: 24

Effect of Emergency Department Crowding on Outcomes of Admitted Patients

Sun,BC; Hsia,RY; Weiss,RE; et al.

Abstract: Study objective: Emergency department(ED)crowding is a prevalent health delivery problem and may adversely affect the outcomes of patients requiring admission. We assess the association of ED crowding with subsequent outcomes in a general population of hospitalized patients.

Methods: We performed a retrospective cohort analysis of patients admitted in 2007 through the EDs of nonfederal,acute care hospitals in California. The primary outcome was inpatient mortality. Secondary outcomes included hospital length of stay and costs. ED crowding was established by the proxy measure of ambulance diversion hours on the day of admission. To control for hospital-level confounders of ambulance diversion,we defined periods of high ED crowding as those days within the top quartile of diversion hours for a specific facility. Hierarchic regression models controlled for demographics,time variables,patient comorbidities,primary diagnosis,and hospital fixed effects. We used bootstrap sampling to estimate excess outcomes attributable to ED crowding.

Results: We studied 995379 ED visits resulting in admission to 187 hospitals. Patients who were admitted on days with high ED crowding experienced 5% greater odds of inpatient death(95% confidence interval [CI] 2% to 8%),0.8% longer hospital length of stay(95% CI 0.5% to 1%),and 1% increased costs per admission(95% CI 0.7% to 2%). Excess outcomes attributable to periods of high ED crowding included 300 inpatient deaths(95% CI 200 to 500 inpatient deaths),6200 hospital days(95% CI 2800 to 8900 hospital days),and $17 million(95% CI $11 to $23 million)in costs.

Conclusion: Periods of high ED crowding were associated with increased inpatient mortality and modest increases in length of stay and costs for admitted patients.

Keywords: ambulance diversion; mortality; association; length; care

来源出版物:Annals of Emergency Medicine,2013,61(6): 605-611联系邮箱:Sun,BC; sunb@ohsu.edu

被引频次: 23

Predictors of poor neurological outcome in adult comatose survivors of cardiac arrest: A systematic review and meta-analysis. Part 2: Patients treated with therapeutic hypothermia

Sandroni,C; Cavallaro,F; Callaway,CW; et al.

Abstract: Aims and methods: To systematically review the accuracy of early(<7 days)predictors of poor outcome,defined as death or vegetative state(Cerebral Performance Categories [CPC] 4-5)or death,vegetative state or severe disability(CPC 3-5),in comatose adult survivors from cardiac arrest(CA)treated using therapeutic hypothermia(TH). Electronic databases were searched for eligible studies. Sensitivity,specificity,and false positive rates(FPR)for each predictor were calculated. Quality of evidence(QOE)was evaluated according to the GRADE guidelines.

Results: 37 studies(2403 patients)were included. A bilaterally absent N20 SSEP wave during TH(4 studies; QOE: Moderate)or after rewarming(5 studies; QOE: Low),a nonreactive EEG background(3 studies; QOE: Low)after rewarming,a combination of absent pupillary light and corneal reflexes plus a motor response no better than extension(M≤2)(1 study; QOE: Very low)after rewarming predicted CPC 3-5 with 0% FPR and narrow(<10%)95% confidence intervals. No consistent threshold for 0% FPR could be identified for blood levels of biomarkers. In 6/8 studies on SSEP,in 1/3 studies on EEG reactivity and in the single study on clinical examination the investigated predictor was used for decisions to withdraw treatment,causing the risk of a self-fulfilling prophecy.

Conclusions: in the first 7 days after CA,a bilaterally absent N20 SSEP wave anytime,a nonreactive EEG after rewarming or a combination of absent ocular reflexes and M<2 after rewarming predicted CPC 3-5 with 0% FPR and narrow 95% CIs,but with a high risk of bias. Keywords: neuron-specific enolase; somatosensory-evoked potentials; postanoxic status epilepticus; anoxic-ischemic coma; cardiopulmonary-resuscitation; mild hypothermia; prognostic value; prospective cohort; bispectral index; prisma statement

来源出版物:Resuscitation,2013,84(10): 1324-1338联系邮箱:Sandroni,C; sandroni@rm.unicatt.it

被引频次: 21

The influence of induced hypothermia and delayed prognostication on the mode of

death after cardiac arrest

Dragancea,I; Rundgren,M; Englund,E; et al.

Abstract: Background: Brain injury is considered the main cause of death in patients who are hospitalized after cardiac arrest(CA). Induced hypothermia is recommended as neuroprotective treatment after(CA)but may affect prognostic parameters. We evaluated the effect of delayed neurological prognostication on the mode of death in hypothermia-treated CA-survivors.

Study design: Retrospective study at a Swedish university hospital,analyzing all in-hospital and out-of-hospital CA-patients treated with hypothermia during a 5-year period. Cause of death was categorized as brain injury,cardiac disorder or other. Multimodal neurological prognostication and decision on level of care was performed in comatose patients 72 h after rewarming. Neurological function was evaluated by Cerebral Performance Categories scale(CPC).

Results: Among 162 patients,76 survived to hospital discharge,65 of whom had a good neurological outcome(CPC 1-2),and 11 were severely disabled(CPC 3). No patient was in vegetative state. The cause of death was classified as brain injury in 61 patients,cardiac disorder in 14 and other in 11. Four patients were declared brain dead and became organ donors. They were significantly younger(median 40 years)and with long time to ROSC. Active intensive care was withdrawn in 50 patients based on a statement of poor neurological prognosis at least 72 h after rewarming. These patients died,mainly from respiratory complications,at a median 7 days after CA.

Conclusion: Following induced hypothermia and delayed neurological prognostication,brain injury remains the main cause of death after CA. Most patients with a poor prognosis statement died within 2 weeks.

Keywords: advanced life-support; therapeutic hypothermia; cardiopulmonary-resuscitation; comatose survivors; care; predictors; sweden;guidelines; admission; quality

来源出版物:Resuscitation,2013,84(3): 337-342联系邮箱:Dragancea,I; irina.dragancea@skane.se

被引频次: 20

Arterial carbon dioxide tension and outcome in patients admitted to the intensive care unit after cardiac arrest

Schneider,AG; Eastwood,GM; Bellomo,R; et al.

Abstract: Background: Arterial carbon dioxide tension(PaCO2)affects neuronal function and cerebral blood flow. However,its association with outcome in patients admitted to intensive care unit(ICU)after cardiac arrest(CA)has not been evaluated.

Methods and results: Observational cohort study using data from the Australian New Zealand(ANZ)Intensive Care Society Adult-Patient-Database(ANZICS-APD). Outcomes analyses were adjusted for illness severity,co-morbidities,hypothermia,treatment limitations,age,year of admission,glucose,source of admission,PaO2and propensity score.

We studied 16542 consecutive patients admitted to 125 ANZ ICUs after CA between 2000 and 2011. Using the APD-PaCO2(obtained within 24 h of ICU admission),3010(18.2%)were classified into the hypo( PaCO2< 35 mmHg),6705(40.5%)into the normo-(35-45 mmHg)and 6827(41.3%)into the hypercapnia(>45 mmHg)group. The hypocapnia group,compared with the normocapnia group,had a trend toward higher in-hospital mortality(OR 1.12 [95% CI 1.00-1.24,p = 0.04]),lower rate of discharge home(OR 0.81 [0.70-0.94,p <0.01])and higher likelihood of fulfilling composite adverse outcome of death and no discharge home(OR 1.23 [1.10-1.37,p < 0.001]). In contrast,the hypercapnia group had similar in-hospital mortality(OR 1.06 [0.97-1.15,p = 0.19])but higher rate of discharge home among survivors(OR 1.16 [1.03-1.32,p = 0.01])and similar likelihood of fulfilling the composite outcome(OR 0.97 [0.89-1.06,p = 0.52]). Cox-proportional hazards modelling supported these findings.

Conclusions: Hypo-and hypercapnia are common after ICU admission post-CA. Compared with normocapnia,hypocapnia was independently associated with worse clinical outcomes and hypercapnia a greater likelihood of discharge home among survivors.

Keywords: cerebral-blood-flow; in-hospital mortality; cardiopulmonary-resuscitation; immature rat; new-zealand; therapeutic hypothermia;mild hypothermia; head-injury; ischemia; brain

来源出版物:Resuscitation,2013,84(7): 927-934联系邮箱:Bellomo,R; rinaldo.bellomo@austin.org.au

ENDOCRINOLOGY METABOLISM 内分泌与代谢

被引频次: 118

On the free radical scavenging activities of melatonin's metabolites,AFMK and AMK

Galano,A; Tan,DX; Reiter,RJ

Abstract: The reactions of N1-acetyl-N2-formyl-5-methoxykynuramine(AFMK)and N1-acetyl-5-methoxykynuramine(AMK)with center dot ·OH,center dot·OOH,and center dot·OOCCl3 radicals have been studied using the density functional theory. Three mechanisms of reaction have been considered: radical adduct formation(RAF),hydrogen transfer(HT),and single electron transfer(SET). Their relative importance for the free radical scavenging activity of AFMK and AMK has been assessed. It was found that AFMK and AMK react with center dot·OH at diffusion-limited rates,regardless of the polarity of the environment,which supports their excellent center dot OH radical scavenging activity. Both compounds were found to be also very efficient for scavenging center dot·OOCCl3,but rather ineffective for scavenging center dot·OOH. Regarding their relative activity,it was found that AFMK systematically is a poorer scavenger than AMK and melatonin. In aqueous solution,AMK was found to react faster than melatonin with all the studied free radicals,while in nonpolar environments,the relative efficiency of AMK and melatonin as free radical scavengers depends on the radical with which they are reacting. Under such conditions,melatonin is predicted to be a better center dot·OOH and center dot·OOCCl3 scavenger than AMK,while AMK is predicted to be slightly better than melatonin for scavenging center dot·OH. Accordingly it seems that melatonin and its metabolite AMKconstitute an efficient team of scavengers able of deactivating a wide variety of reactive oxygen species,under different conditions. Thus,the presented results support the continuous protection exerted by melatonin,through the free radical scavenging cascade.

Keywords: reactive oxygen; in-vitro; antioxidative protection; density functionals; electron-transfer; brain metabolite; biogenic-amines;N-1-acetyl-5-methoxykynuramine; oxidation; DNA

来源出版物:Journal of Pineal Research,2013,54(3): 245-257联系邮箱:Galano,A; agal@xanum.uam.mx

被引频次: 104

Dietary(Poly)phenolics in Human Health: Structures,Bioavailability,and Evidence of Protective Effects Against Chronic Diseases

Del Rio,D; Rodriguez-Mateos,A; Spencer,JPE; et al.

Abstract: Human intervention trials have provided evidence for protective effects of various(poly)phenol-rich foods against chronic disease,including cardiovascular disease,neurodegeneration,and cancer. While there are considerable data suggesting benefits of(poly)phenol intake,conclusions regarding their preventive potential remain unresolved due to several limitations in existing studies. Bioactivity investigations using cell lines have made an extensive use of both(poly)phenolic aglycones and sugar conjugates,these being the typical forms that exist in planta,at concentrations in the low-mu M-to-mM range. However,after ingestion,dietary(poly)phenolics appear in the circulatory system not as the parent compounds,but as phase II metabolites,and their presence in plasma after dietary intake rarely exceeds nM concentrations. Substantial quantities of both the parent compounds and their metabolites pass to the colon where they are degraded by the action of the local microbiota,giving rise principally to small phenolic acid and aromatic catabolites that are absorbed into the circulatory system. This comprehensive review describes the different groups of compounds that have been reported to be involved in human nutrition,their fate in the body as they pass through the gastrointestinal tract and are absorbed into the circulatory system,the evidence of their impact on human chronic diseases,and the possible mechanisms of action through which(poly)phenol metabolites and catabolites may exert these protective actions. It is concluded that better performed in vivo intervention and in vitro mechanistic studies are needed to fully understand how these molecules interact with human physiological and pathological processes.

Keywords: coronary-artery-disease; improves endothelial function; concord grape juice; flavanol-rich cocoa; low-density-lipoprotein;oxidative dna-damage; randomized controlled-trial; green tea flavan-3-ols; performance liquid-chromatography; cardiovascular risk-factors

来源出版物:Antioxidants & Redox Signaling,2013,18(14): 1818-1892联系邮箱:Crozier,A; alan.crozier@glasgow.ac.uk

被引频次: 102

Marked Expansion of Exocrine and Endocrine Pancreas With Incretin Therapy in Humans With Increased Exocrine Pancreas Dysplasia and the Potential for Glucagon-Producing Neuroendocrine Tumors

Butler,AE; Campbell-Thompson,M; Gurlo,T; et al.

Abstract: Controversy exists regarding the potential regenerative influences of incretin therapy on pancreatic beta-cells versus possible adverse pancreatic proliferative effects. Examination of pancreata from age-matched organ donors with type 2 diabetes mellitus(DM)treated by incretin therapy(n=8)or other therapy(n=12)and nondiabetic control subjects(n =14)reveals an similar to 40% increased pancreatic mass in DM treated with incretin therapy,with both increased exocrine cell proliferation(P<0.0001)and dysplasia(increased pancreatic intraepithelial neoplasia,P <0.01). Pancreata,in DM treated with incretin therapy were notable for alpha-cell hyperplasia and glucagon-expressing microadenomas(3 of 8)and a neuroendocrine tumor. beta-Cell mass was reduced by similar to 60% in those with DM,yet a sixfold increase was observed in incretin-treated subjects,although DM persisted. Endocrine cells costaining for insulin and glucagon were increased in DM compared with non-DM control subjects(P <0.05)and markedly further increased by incretin therapy(P<0.05). In conclusion,incretin therapy in humans resulted in a marked expansion of the exocrine and endocrine pancreatic compartments,the former being accompanied by increased proliferation and dysplasia and the latter by alpha-cell hyperplasia with the potential for evolution into neuroendocrine tumors.

Keywords: beta-cell function; type-2 diabetes-mellitus; glucose-tolerance; european subjects; alpha; proliferation; sitagliptin; metformin;receptor; rats

来源出版物:Diabetes,2013,62(7): 2595-2604联系邮箱:Butler,AE; aebutler@mednet.ucla.edu

被引频次: 85

European guidance for the diagnosis and management of osteoporosis in postmenopausal women

Kanis,JA; McCloskey,EV; Johansson,H; et al.

Abstract: Guidance is provided in a European setting on the assessment and treatment of postmenopausal women at risk of fractures due to osteoporosis.

The International Osteoporosis Foundation and European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis published guidance for the diagnosis and management of osteoporosis in 2008. This manuscript updates these in a European setting.

Systematic literature reviews.

The following areas are reviewed: the role of bone mineral density measurement for the diagnosis of osteoporosis and assessment of fracture risk,general and pharmacological management of osteoporosis,monitoring of treatment,assessment of fracture risk,case finding strategies,investigation of patients and health economics of treatment.

A platform is provided on which specific guidelines can be developed for national use.

Keywords: bone-mineral density; vertebral fracture risk; randomized controlled-trial; estrogen plus progestin; x-ray absorptiometry; glucocorticoid-induced osteoporosis; position development conference; increased cardiovascular risks; prior bisphosphonate therapy; hormone replacement therapy

来源出版物:Osteoporosis International,2013,24(1): 23-57联系邮箱:Kanis,JA; w.j.pontefract@sheffield.ac.uk

被引频次: 81

A review of the molecular aspects of melatonin's anti-inflammatory actions: recent insights and new perspectives

Mauriz,JL; Collado,PS; Veneroso,C; et al.

Abstract: Melatonin is a highly evolutionary conserved endogenous molecule that is mainly produced by the pineal gland,but also by other nonendocrine organs,of most mammals including man. In the recent years,a variety of anti-inflammatory and antioxidant effects have been observed when melatonin is applied exogenously under both in vivo and in vitro conditions. A number of studies suggest that this indole may exert its anti-inflammatory effects through the regulation of different molecular pathways. It has been documented that melatonin inhibits the expression of the isoforms of inducible nitric oxide synthase and cyclooxygenase and limits the production of excessive amounts of nitric oxide,prostanoids,and leukotrienes,as well as other mediators of the inflammatory process such as cytokines,chemokines,and adhesion molecules. Melatonin's anti-inflammatory effects are related to the modulation of a number of transcription factors such as nuclear factor kappa B,hypoxia-inducible factor,nuclear factor erythroid 2-related factor 2,and others. Melatonin's effects on the DNA-binding capacity of transcription factors may be regulated through the inhibition of protein kinases involved in signal transduction,such as mitogen-activated protein kinases. This review summarizes recent research data focusing on the modulation of the expression of different inflammatory mediators by melatonin and the effects on cell signaling pathways responsible for the indole's anti-inflammatory activity. Although there are a numerous published reports that have analyzed melatonin's anti-inflammatory properties,further studies are necessary to elucidate its complex regulatory mechanisms in different cellular types and tissues.

Keywords: nf-kappa-b; nitric-oxide synthase; cell-adhesion molecule-1; intracellular signaling pathways; erythroid 2-related factor-2; nuclear factor-kappab; c-reactive protein; fulminant hepatic-failure; induced gastric-lesions; human endothelial-cells

来源出版物:Journal of Pineal Research,2013,54(1): 1-14联系邮箱:Gonzalez-Gallego,J; jgonga@unileon.es

ENERGY FUELS 能源与燃料

被引频次: 296

Solar cell efficiency tables(version 41)

Green,MA; Emery,K; Hishikawa,Y; et al.

Abstract: Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined,and new entries since June 2012 are reviewed.

Keywords: multicrystalline; concentrator; stability

来源出版物:Progress in Photovoltaics,2013,21(1): 1-11联系邮箱:Green,MA; m.green@unsw.edu.au

被引频次: 196

Thin film solar cell with 8.4% power conversion efficiency using an earth-abundant Cu2ZnSnS4 absorber

Shin,B; Gunawan,O; Zhu,Y; et al.

Abstract: Using vacuum process,we fabricated Cu2ZnSnS4 solar cells with 8.4% efficiency,a number independently certified by an external,accredited laboratory. This is the highest efficiency reported for pure sulfide Cu2ZnSnS4 prepared by any method. Consistent with literature,the optimal composition is Cu-poor and Zn-rich despite the precipitation of secondary phases(e.g.,ZnS). Despite a very thin absorber thickness(similar to 600 nm),a reasonably good short-circuit current was obtained. Time-resolved photoluminescence measurements suggest a minority carrier-diffusion length on the order of several hundreds of nanometers and relatively good collection of photo-carriers across the entire absorber thickness.

Keywords: photovoltaics

来源出版物:Progress in Photovoltaics,2013,21(1): 72-76联系邮箱:Guha,S; guha@us.ibm.com

被引频次: 184

Low-temperature processed meso-superstructured to thin-film perovskite solar cells

Ball,JM; Lee,MM; Hey,A; et al.

Abstract: We have reduced the processing temperature of the bulk absorber layer in CH3NH3PbI3-xClx perovskite solar cells from 500 to<150 degrees C and achieved power conversion efficiencies up to 12.3%. Remarkably,we find that devices with planar thin-film architecture,where the ambipolar perovskite transports both holes and electrons,convert the absorbed photons into collected charge with close to 100% efficiency.

Keywords: organometal halide perovskites; high-efficiency; photovoltaic cells; low-cost; tio2; performance

来源出版物:Energy & Environmental Science,2013,6(6): 1739-1743联系邮箱:Ball,JM; h.snaith1@physics.ox.ac.uk

被引频次: 170

Solar cell efficiency tables(version 42)

Green,MA; Emery,K; Hishikawa,Y; et al.

Abstract: Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined,and new entries since January 2013 are reviewed.

Keywords: multicrystalline; concentrator; stability; module

来源出版物:Progress in Photovoltaics,2013,21(5): 827-837联系邮箱:Green,MA; m.green@unsw.edu.au

被引频次: 142

3D carbon based nanostructures for advanced supercapacitors

Jiang,H; Lee,PS; Li,CZ

Abstract: Supercapacitors have attracted intense attention due to their great potential to meet the demand of both high energy density and power density in many advanced technologies. Various carbon-based nanocomposites are currently pursued as supercapacitor electrodes because of the synergistic effect between carbon(high power density)and pseudo-capacitive nanomaterials(high energy density). This feature article aims to review most recent progress on 3D(3D)carbon based nanostructures for advanced supercapacitor applications in view of their structural intertwinement which not only create the desired hierarchical porous channels,but also possess higher electrical conductivity and better structural mechanical stability. The carbon nanostructures comprise of CNTs-based networks,graphene-based architectures,hierarchical porous carbon-based nanostructures and other even more complex carbon-based 3D configurations. Their advantages and disadvantages are compared and summarized based on the results published in the literature. In addition,we also discuss and view the ongoing trends in materials development for advanced supercapacitors.

Keywords: capacitive energy-storage; double-layer capacitors; ordered mesoporous carbons; electrochemical capacitors; nanotube electrodes; nanowire composites; nanoporous carbon; graphene; performance; oxide

来源出版物:Energy & Environmental Science,2013,6(1): 41-53联系邮箱:Jiang,H; czli@ecust.edu.cn

ENGINEERING AEROSPACE 航空航天工程

被引频次: 18

Multidisciplinary Design Optimization: A Survey of Architectures

Martins,JRRA; Lambe,AB

Abstract: Multidisciplinary design optimization is a field of research that studies the application of numerical optimization techniques to the design of engineering systems involving multiple disciplines or components. Since the inception of multidisciplinary design optimization,various methods(architectures)have been developed and applied to solve multidisciplinary design-optimization problems. This paper provides a survey of all the architectures that have been presented in the literature so far. All architectures are explained in detail using a unified description that includes optimization problem statements,diagrams,and detailed algorithms. The diagrams show both data and process flow through the multidisciplinary system and computational elements,which facilitate the understanding of the various architectures,and how they relate to each other. A classification of the multidisciplinary design-optimization architectures based on their problem formulations and decomposition strategies is also provided,and the benefits and drawbacks of the architectures are discussed from both theoretical and experimental perspectives. For each architecture,several applications to the solution of engineering-design problems are cited. The result is a comprehensive but straightforward introduction to multidisciplinary design optimization for nonspecialists and a reference detailing all current multidisciplinary design-optimization architectures for specialists.

Keywords: integrated-system synthesis; aircraft conceptual design; augmented lagrangian coordination; response-surface approximations;aerodynamic-structural design; distributed optimal-design; model-based decomposition; collaborative optimization; sensitivity-analysis;vehicle design

来源出版物:AIAA Journal,2013,51(9): 2049-2075

被引频次: 17

A refined trigonometric shear deformation theory for thermoelastic bending of functionally graded sandwich plates

Tounsi,A; Houari,MSA; Benyoucef,S; et al.

Abstract: A refined trigonometric shear deformation theory(RTSDT)taking into account transverse shear deformation effects is presented for the thermoelastic bending analysis of functionally graded sandwich plates. Unlike any other theory,the number of unknown functions involved is only four,as against five in case of other shear deformation theories. The theory presented is variationally consistent,does not require shear correction factor,the displacement components are expressed by trigonometric series representation through the plate thickness to develop a two-dimensional theory and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. The sandwich with homogeneous facesheet and FGM core is considered. Material properties of the present FGM core are assumed to vary according to a power law distribution in terms of the volume fractions of the constituents. The influences played by the transverse shear deformation,thermal load,plate aspect ratio,and volume fraction distribution are studied. Numerical results for deflections and stresses of functionally graded metal-ceramic plates are investigated. It can be concluded that the proposed theory is accurate and simple in solving the thermoelastic bending behavior of functionally graded plates.

Keywords: electro-elastic plates; composite plates; mechanical-behavior; order theory; element; layer; stresses; loadings; core

来源出版物:Aerospace Science and Technology,2013,24(1): 209-220联系邮箱:Tounsi,A; tou_abdel@yahoo.com

被引频次: 15

Knowledge-Aided(Potentially Cognitive)Transmit Signal and Receive Filter Design in Signal-Dependent Clutter

Aubry,A; De Maio,A; Farina,A; et al.

Abstract: We consider the problem of knowledge-aided(possibly cognitive)transmit signal and receive filter design for point-like targets in signal-dependent clutter. We suppose that the radar system has access to a(potentially dynamic)database containing a geographical information system(GIS),which characterizes the terrain to be illuminated,and some a priori electromagnetic reflectivity and spectral clutter models,which allow the raw prediction of the actual scattering environment. Hence,we devise an optimization procedure for the transmit signal and the receive filter which sequentially improves the signal-to-interference-plus-noise ratio(SINR). Each iteration of the algorithm,whose convergence is analytically proved,requires the solution of both a convex and a hidden convex optimization problem. The resulting computational complexity is linear with the number of iterations and polynomial with the receive filter length. At the analysis stage we assess the performance of the proposed technique in the presence of either a homogeneous ground clutter scenario or a heterogeneous mixed land and sea clutter environment.

Keywords: wave-form design; polyphase barker sequences; radar detection; optimization; performance; constraint; codes

来源出版物:IEEE Transactions on Aerospace and Electronic Systems,2013,49(1): 93-117联系邮箱:Aubry,A; ademaio@unina.it

被引频次: 13

Robust Autopilot Design for Bank-to-Turn Missiles using Disturbance Observers

Li,SH; Yang,J

Abstract: A decoupling control strategy consisting of robust feedback and feedforward compensation based on disturbance-observers is proposed for bank-to-turn(BTT)missile autopilot. For each of the three channels,the lumped disturbances,which consist of nonlinear couplings and external disturbances,are estimated by a disturbance observer and then feedforward compensated. Three distributed robust state feedback controllers are designed to stabilize the rest linear parts of three channels,respectively. Simulation studies demonstrate the effectiveness of the proposed method.

Keywords: basis function networks; controller-design; neural-networks; high-speed; systems; manipulators; rejection; motor

来源出版物:IEEE Transactions on Aerospace and Electronic Systems,2013,49(1): 558-579联系邮箱:Li,SH; lsh@seu.edu.cn

被引频次: 11

Bonded repair of composite aircraft structures: A review of scientific challenges and opportunities

Katnam,KB; Da Silva,LFM; Young,TM

Abstract: Advanced composite materials have gained popularity in high-performance structural designs such as aerospace applications that require lightweight components with superior mechanical properties in order to perform in demanding service conditions as well as provide energy efficiency. However,one of the major challenges that the aerospace industry faces with advanced composites - because of their inherent complex damage behaviour - is structural repair. Composite materials are primarily damaged by mechanical loads and/or environmental conditions. If material damage is not extensive,structural repair is the only feasible solution as replacing the entire component is notcost-effective in many cases. Bonded composite repairs(e.g. scarf patches)are generally preferred as they provide enhanced stress transfer mechanisms,joint efficiencies and aerodynamic performance. With an increased usage of advanced composites in primary and secondary aerospace structural components,it is thus essential to have robust,reliable and repeatable structural bonded repair procedures to restore damaged composite components. But structural bonded repairs,especially with primary structures,pose several scientific challenges with the current existing repair technologies. In this regard,the area of structural bonded repair of composites is broadly reviewed - starting from damage assessment to automation - to identify current scientific challenges and future opportunities.

Keywords: fiber-reinforced plastics; mechanically fastened joints; scanning laser vibrometry; impact damage detection; adhesive joints;scarf repairs; void formation; surface-treatment; lamb waves; nondestructive inspection

来源出版物:Progress in Aerospace Sciences,2013,61: 26-42联系邮箱:Katnam,KB; kali-babu.katnam@ul.ie

ENGINEERING BIOMEDICAL 生物医学工程

被引频次: 130

Review of bioactive glass: From Hench to hybrids

Jones,JR

Abstract: Bioactive glasses are reported to be able to stimulate more bone regeneration than other bioactive ceramics but they lag behind other bioactive ceramics in terms of commercial success. Bioactive glass has not yet reached its potential but research activity is growing. This paper reviews the current state of the art,starting with current products and moving onto recent developments. Larry Hench's 4555 Bioglass(R)was the first artificial material that was found to form a chemical bond with bone,launching the field of bioactive ceramics. In vivo studies have shown that bioactive glasses bond with bone more rapidly than other bioceramics,and in vitro studies indicate that their osteogenic properties are due to their dissolution products stimulating osteoprogenitor cells at the genetic level. However,calcium phosphates such as tricalcium phosphate and synthetic hydroxyapatite are more widely used in the clinic. Some of the reasons are commercial,but others are due to the scientific limitations of the original Bioglass 45S5. An example is that it is difficult to produce porous bioactive glass templates(scaffolds)for bone regeneration from Bioglass 45S5 because it crystallizes during sintering. Recently,this has been overcome by understanding how the glass composition can be tailored to prevent crystallization. The sintering problems can also be avoided by synthesizing sol-gel glass,where the silica network is assembled at room temperature. Process developments in foaming,solid freeform fabrication and nanofibre spinning have now allowed the production of porous bioactive glass scaffolds from both melt- and sol-gel-derived glasses. An ideal scaffold for bone regeneration would share load with bone. Bioceramics cannot do this when the bone defect is subjected to cyclic loads,as they are brittle. To overcome this,bioactive glass polymer hybrids are being synthesized that have the potential to be tough,with congruent degradation of the bioactive inorganic and the polymer components. Key to this is creating nanoscale interpenetrating networks,the organic and inorganic components of which have covalent coupling between them,which involves careful control of the chemistry of the sol-gel process. Bioactive nanoparticles can also now be synthesized and their fate tracked as they are internalized in cells. This paper reviews the main developments in the field of bioactive glass and its variants,covering the importance of control of hierarchical structure,synthesis,processing and cellular response in the quest for new regenerative synthetic bone grafts. The paper takes the reader from Hench's Bioglass 45S5 to new hybrid materials that have tailorable mechanical properties and degradation rates.

Keywords: cells in-vitro; bone-graft substitutes; sol-gel method; intrabony periodontal defects; camphene-based suspensions; angiogenic growth-factors; tibial plateau fractures; mesenchymal stem-cells; melt-derived 45s5; x-ray-diffraction

来源出版物:Acta Biomaterialia,2013,9(1): 4457-4486联系邮箱:Jones,JR; julian.r.jones@imperial.ac.uk

被引频次: 90

Dual and multi-stimuli responsive polymeric nanoparticles for programmed site-specific drug delivery

Cheng,R; Meng,FH; Deng,C; et al.

Abstract: In the past decades,polymeric nanoparticles have emerged as a most promising and viable technology platform for targeted and controlled drug delivery. As vehicles,ideal nanoparticles are obliged to possess high drug loading levels,deliver drug to the specific pathological site and/or target cells without drug leakage on the way,while rapidly unload drug at the site of action. To this end,various "intelligent" polymeric nanoparticles that release drugs in response to an internal or external stimulus such as pH,redox,temperature,magnetic and light have been actively pursued. These stimuli-responsive nanoparticles have demonstrated,though to varying degrees,improved in vitro and/or in vivo drug release profiles. In an effort to further improve drug release performances,novel dual and multi-stimuli responsive polymeric nanoparticles that respond to a combination of two or more signals such as pH/temperature,pH/redox,pH/magnetic field,temperature/reduction,double pH,pH and diols,temperature/magnetic field,temperature/enzyme,temperature/pH/redox,temperature/pH/magnetic,pH/redox/magnetic,temperature/redox/guest molecules,and temperature/pH/guest molecules have recently been developed. Notably,these combined responses take place either simultaneously at the pathological site or in a sequential manner from nanopartide preparation,nanopartide transporting pathways,to cellular compartments. These dual and multi-stimuli responsive polymeric nanoparticles have shown unprecedented control over drug delivery and release leading to superior in vitro and/or in vivo anti-cancer efficacy. Withprogrammed site-specific drug delivery feature,dual and multi-stimuli responsive nanoparticulate drug formulations have tremendous potential for targeted cancer therapy. In this review paper,we highlight the recent exciting developments in dual and multi-stimuli responsive polymeric nanoparticles for precision drug delivery applications,with a particular focus on their design,drug release performance,and therapeutic benefits.

Keywords: cross-linked micelles; block-copolymer micelles; core-shell nanoparticles; iron-oxide nanoparticles; magnetic nanoparticles;intracellular drug; biodegradable micelles; controlled-release; triggered release; disulfide linkage

来源出版物:Biomaterials,2013,34(14): 3647-3657联系邮箱:Zhong,ZY; zyzhong@suda.edu.cn

被引频次: 63

X-ray phase-contrast imaging: from pre-clinical applications towards clinics

Bravin,A; Coan,P; Suortti,P

Abstract: Phase-contrast x-ray imaging(PCI)is an innovative method that is sensitive to the refraction of the x-rays in matter. PCI is particularly adapted to visualize weakly absorbing details like those often encountered in biology and medicine. In past years,PCI has become one of the most used imaging methods in laboratory and preclinical studies: its unique characteristics allow high contrast 3D visualization of thick and complex samples even at high spatial resolution. Applications have covered a wide range of pathologies and organs,and are more and more often performed in vivo. Several techniques are now available to exploit and visualize the phase-contrast: propagation-and analyzer-based,crystal and grating interferometry and non-interferometric methods like the coded aperture. In this review,covering the last five years,we will give an overview of the main theoretical and experimental developments and of the important steps performed towards the clinical implementation of PCI.

Keywords: small-angle scattering; cancer in-vitro; computed-tomography; synchrotron-radiation; grating interferometer; high-resolution;refraction contrast; articular-cartilage; high-energy; medical applications

来源出版物:Physics in Medicine and Biology,2013,58(1): R1-R35联系邮箱:Bravin,A; bravin@esrf.fr

被引频次: 61

Optical properties of biological tissues: a review

Jacques,SL

Abstract: A review of reported tissue optical properties summarizes the wavelength-dependent behavior of scattering and absorption. Formulae are presented for generating the optical properties of a generic tissue with variable amounts of absorbing chromophores(blood,water,melanin,fat,yellow pigments)and a variable balance between small-scale scatterers and large-scale scatterers in the ultrastructures of cells and tissues.

Keywords: time-resolved spectroscopy; monte-carlo simulations; light-scattering; blood-flow; diffuse-reflectance; laser irradiation; frequency-domain; female breast; turbid media; absorption

来源出版物:Physics in Medicine and Biology,2013,58(11): R37-R61联系邮箱:Jacques,SL; jacquess@ohsu.edu

被引频次: 46

Nanostructured scaffolds for bone tissue engineering

Li,XM; Wang,L; Fan,YB; et al.

Abstract: It has been demonstrated that nanostructured materials,compared with conventional materials,may promote greater amounts of specific protein interactions,thereby more efficiently stimulating new bone formation. It has also been indicated that,when features or ingredients of scaffolds are nanoscaled,a variety of interactions can be stimulated at the cellular level. Some of those interactions induce favorable cellular functions while others may leads to toxicity. This review presents the mechanism of interactions between nanoscaled materials and cells and focuses on the current research status of nanostructured scaffolds for bone tissue engineering. Firstly,the main requirements for bone tissue engineering scaffolds were discussed. Then,the mechanism by which nanoscaled materials promote new bone formation was explained,following which the current research status of main types of nanostructured scaffolds for bone tissue engineering was reviewed and discussed.

Keywords: osteoblast-like cells; in-vitro; mechanical-properties; composite scaffolds; carbon nanotubes; physical-properties; chitin fibers;delivery; regeneration; adhesion

来源出版物:Journal of Biomedical Materials Research Part A,2013,101(8): 2424-2435联系邮箱:Li,XM; x.m.li@hotmail.com

ENGINEERING CHEMICAL 化学工程

被引频次: 184

Low-temperature processed meso-superstructured to thin-film perovskite solar cells

Ball,JM; Lee,MM; Hey,A; et al.

Abstract: We have reduced the processing temperature of the bulk absorber layer in CH3NH3PbI3-xClx perovskite solar cells from 500 to<150 degrees C and achieved power conversion efficiencies up to 12.3%. Remarkably,we find that devices with planar thin-film architecture,where the ambipolar perovskite transports both holes and electrons,convert the absorbed photons into collected charge with close to 100% efficiency.

Keywords: organometal halide perovskites; high-efficiency; photovoltaic cells; low-cost; TiO2; performance

来源出版物:Energy & Environmental Science,2013,6(6): 1739-1743联系邮箱:Ball,JM; h.snaith1@physics.ox.ac.uk

被引频次: 142

3D carbon based nanostructures for advanced supercapacitors

Jiang,H; Lee,PS; Li,CZ

Abstract: Supercapacitors have attracted intense attention due to their great potential to meet the demand of both high energy density and power density in many advanced technologies. Various carbon-based nanocomposites are currently pursued as supercapacitor electrodes because of the synergistic effect between carbon(high power density)and pseudo-capacitive nanomaterials(high energy density). This feature article aims to review most recent progress on 3D(3D)carbon based nanostructures for advanced supercapacitor applications in view of their structural intertwinement which not only create the desired hierarchical porous channels,but also possess higher electrical conductivity and better structural mechanical stability. The carbon nanostructures comprise of CNTs-based networks,graphene-based architectures,hierarchical porous carbon-based nanostructures and other even more complex carbon-based 3D configurations. Their advantages and disadvantages are compared and summarized based on the results published in the literature. In addition,we also discuss and view the ongoing trends in materials development for advanced supercapacitors.

Keywords: capacitive energy-storage; double-layer capacitors; ordered mesoporous carbons; electrochemical capacitors; nanotube electrodes; nanowire composites; nanoporous carbon; graphene; performance; oxide

来源出版物:Energy & Environmental Science,2013,6(1): 41-53联系邮箱:Jiang,H; czli@ecust.edu.cn

被引频次: 117

Room-temperature stationary sodium-ion batteries for large-scale electric energy storage

Pan,HL; Hu,YS; Chen,LQ

Abstract: Room-temperature stationary sodium-ion batteries have attracted great attention particularly in large-scale electric energy storage applications for renewable energy and smart grid because of the huge abundant sodium resources and low cost. In this article,a variety of electrode materials including cathodes and anodes as well as electrolytes for room-temperature stationary sodium-ion batteries are briefly reviewed. We compare the difference in storage behavior between Na and Li in their analogous electrodes and summarize the sodium storage mechanisms in the available electrode materials. This review also includes some new results from our group and our thoughts on developing new materials. Some perspectives and directions on designing better materials for practical applications are pointed out based on knowledge from the literature and our experience. Through this extensive literature review,the search for suitable electrode and electrolyte materials for stationary sodium-ion batteries is still challenging. However,after intensive research efforts,we believe that low-cost,long-life and room-temperature sodium-ion batteries would be promising for applications in large-scale energy storage system in the near future.

Keywords: rechargeable lithium batteries; long cycle life; oxide intergrowth electrodes; performance anode material; superior rate capability; rate cathode material; x-ray-diffraction; high-capacity; electrochemical properties; low-cost

来源出版物:Energy & Environmental Science,2013,6(8): 2338-2360联系邮箱:Pan,HL; yshu@aphy.iphy.ac.cn

被引频次: 101

Highly efficient dye-sensitized solar cells: progress and future challenges

Zhang,SF; Yang,XD; Numata,YH; et al.

Abstract: High energy conversion efficiency is one of the most important keys to the commercialization of dye-sensitized solar cells(DSCs)in the huge electricity generation market. According to our experience in the persistent efforts that helped to achieve high efficiency DSCs,we selectively review the major progress of improving the energy conversion efficiency of DSCs which may be useful for future applications. We start the discussion from modelling the device by macroscopic equivalent circuit and then highlight some approaches to improve the device performance,such as the molecular engineering of novel dye sensitizers and light trapping effect,tuning the potential of redox shuttles and surface passivation of photoelectrodes,and optimizing the resistance. Finally,we illustrate a roadmap of possible futuredirections of DSCs with the challenges of how to further improve the efficiency to accelerate the progress in the commercialization of DSCs.

Keywords: nanocrystalline TiO2films; high-conversion-efficiency; charge-transfer sensitizers; open-circuit photovoltage; near-ir sensitization; free organic-dyes; nanostructured TiO2; molecular design; cyanine dyes; co-sensitization

来源出版物:Energy & Environmental Science,2013,6(5): 1443-1464联系邮箱:Zhang,SF; HAN.liyuan@nims.go.jp

被引频次: 94

Photoelectrochemical cells for solar hydrogen production: current state of promising photoelectrodes,methods to improve their properties,and outlook

Li,ZS; Luo,WJ; Zhang,ML; et al.

Abstract: Harnessing solar energy for the production of clean hydrogen fuels by a photoelectrochemical(PEC)cell represents a very attractive but challenging alternative. This review focuses on recent developments of some promising photoelectrode materials,such as Bi-VO4,a-Fe2O3,TaON,and Ta3N5for solar hydrogen production. Some strategies have been developed to improve PEC performances of the photoelectrode materials,including:(i)doping for enhancing visible light absorption in the wide bandgap semiconductor or promoting charge transport in the narrow bandgap semiconductor,respectively;(ii)surface treatment for removing segregation phase or surface states;(iii)electrocatalysts for decreasing the overpotentials;(iv)morphology control for enhancing the light absorption and shortening transfer distance of minority carriers;(v)other methods,such as sensitization,passivating layer,and band structure engineering using heterojunction structures,and so on. Photochemical durability of the photoelectrodes is also discussed,since any potential PEC technology must balance efficiency against cost and photochemical durability. Photochemical durability may be amended by optimizing the photoelectrode,electrocatalyst,and electrolyte at the same time. In addition,solar seawater splitting is briefly introduced because it has received attention recently. Finally,trends in research in PEC cells for solar hydrogen production are detailed.

Keywords: visible-light irradiation; scanning electrochemical microscopy; oxygen-evolving catalyst; atomic layer deposition; TiO2nanowire arrays; photocatalytic water oxidation; ultrasonic spray-pyrolysis; oxynitride taon photoanode; metal-oxide photoanodes; Ta3N5nanotube arrays

来源出版物:Energy & Environmental Science,2013,6(2): 347-370联系邮箱:Li,ZS; zsli@nju.edu.cn

ENGINEERING CIVIL 土木工程

被引频次: 49

Adsorptive removal of hazardous materials using metal-organic frameworks(MOFs): A review

Khan,NA; Hasan,Z; Jhung,SH

Abstract: Efficient removal of hazardous materials from the environment has become an important issue from a biological and environmental standpoint. Adsorptive removal of toxic components from fuel,wastewater or air is one of the most attractive approaches for cleaning technologies. Recently,porous metal-organic framework(MOF)materials have been very promising in the adsorption/separation of various liquids and gases due to their unique characteristics. This review summarizes the recent literatures on the adsorptive removal of various hazardous compounds mainly from fuel,water,and air by virgin or modified MOF materials. Possible interactions between the adsorbates and active adsorption sites of the MOFs will be also discussed to understand the adsorption mechanism. Most of the observed results can be explained with the following mechanisms:(1)adsorption onto a coordinatively unsaturated site,(2)adsorption via acid-base interaction,(3)adsorption via pi-complex formation,(4)adsorption via hydrogen bonding,(5)adsorption via electrostatic interaction,and(6)adsorption based on the breathing properties of some MOFs and so on.

Keywords: carbon-dioxide capture; science-and-technology; activated carbon; heavy-metal; coordination polymers; aqueous-solutions;CO2adsorption; gas-adsorption; high-capacity; ion-exchange

来源出版物:Journal of Hazardous Materials,2013,244: 444-456联系邮箱:Jhung,SH; sung@knu.ac.kr

被引频次: 35

Ag3PO4/graphene-oxide composite with remarkably enhanced visible-light-driven photocatalytic activity toward dyes in water

Chen,GD; Sun,M; Wei,Q; et al.

Abstract: Ag3PO4/graphene-oxide(Ag3PO4/GO)composite has been synthesized by a liquid phase deposition method,and used for the photodegradation of organic dyes in water under visible light. The as-synthesized samples were characterized by X-ray diffraction,scanning electron microscope,N-2 sorption-desorption,and UV-vis diffuse reflectance spectra. The SEM image indicated that Ag3PO4particles were mainly distributed on the surface of GO sheets uniformly. DRS analysis revealed that the samples had good visible light response. The photocatalytic activity of Ag3PO4/GO composite was evaluated by decomposing of dyes(such as methyl orange,rhodamine B)in water under visible or UV-vis light irradiation. The degradation results indicated that the photocatalytic performance of Ag3PO4/GO was greatlyenhanced due to the improved adsorption performance and separation efficiency of photo-generated carriers. The Ag3PO4/GO composite with GO content of 15 wt.% exhibited superior activity under visible light irradiation. After 50 min of reaction,the degradation ratio of MO was about 86.7%,while RhB solution could be completely degraded within 30 min of reaction. Further study proved that the direct oxidation of pollutants by holes has played a major role in the degradation process. The results of this work would provide a new sight for the construction of visible light-responsive photocatalysts with high performance.

Keywords: TiO2photocatalysis; graphene oxide; waste-water; degradation; textile; semiconductor; irradiation; removal; nanocomposites;nanocrystals

来源出版物:Journal of Hazardous Materials,2013,244: 86-93联系邮箱:Sun,M; smlcu@163.com

被引频次: 34

FRP-confined concrete in circular sections: Review and assessment of stress-strain models

Ozbakkaloglu,T; Lim,JC; Vincent,T

Abstract: An important application of FRP composites is as a confining material for concrete,in both the seismic retrofit of existing reinforced concrete columns and in the construction of concrete-filled FRP tubes as earthquake-resistant columns in new construction. Reliable design of these structural members necessitates clear understanding and accurate modeling of the stress-strain behavior of FRP-confined concrete. To that end,a great number of studies have been conducted in the past two decades,which has led to the development of a large number of models to predict the stress-strain behavior of FRP-confined concrete under axial compression. This paper presents a comprehensive review of 88 models developed to predict the axial stress-strain behavior of FRP-confined concrete in circular sections. Each of the reviewed models and their theoretical bases are summarized and the models are classified into two broad categories,namely design-oriented and analysis-oriented models. This review summarizes the current published literature until the end of 2011,and presents a unified framework for future reference. To provide a comprehensive assessment of the performances of the reviewed models,a large and reliable test database containing the test results of 730 FRP-confined concrete cylinders tested under monotonic axial compression is first established. The perfotmance of each existing stress-strain model is then assessed using this database,and the results of this assessment are presented through selected statistical indicators. In the final part of the paper,a critical discussion is presented on the important factors that influenced the overall performances of the models. A close examination of results of the model assessment has led to a number of important conclusions on the strengths and weaknesses of the existing stress-strain models,which are clearly summarized. Based on these observations,a number of recommendations regarding future research directions are also outlined.

Keywords: fiber-reinforced polymer; high-strength concrete; axial-compression experiments; composite jackets; constitutive relationship;uniaxial compression; failure criterion; design equations; carbon composite; short columns

来源出版物:Engineering Structures,2013,49: 1068-1088联系邮箱:Ozbakkaloglu,T; togay.ozbakkaloglu@adelaide.edu.au

被引频次: 32

Axial Compressive Behavior of Square and Rectangular High-Strength Concrete-Filled FRP Tubes

Ozbakkaloglu,T

Abstract: This paper presents results of an experimental study on the behavior of square and rectangular high-strength concrete(HSC)-filled fiber-reinforced polymer(FRP)tubes(HSCFFT)under concentric compression. The effects of the tube thickness,sectional aspect ratio,and corner radius on the axial compressive behavior of concrete-filled FRP tubes(CFFT)were investigated experimentally through the tests of 24 CFFTs that were manufactured using unidirectional carbon fiber sheets and high-strength concrete with 78 MPa average compressive strength. As the first experimental investigation on the axial compressive behavior of square and rectangular HSCFFTs,the results of the study reported in this paper allow a number of significant conclusions to be drawn. First and foremost,test results indicate that sufficiently confined square and rectangular HSCFFTs can exhibit highly ductile behavior. The results also indicate that confinement effectiveness of FRP tubes increases with an increase in corner radius and decreases with an increase in sectional aspect ratio. It is also observed and discussed that HSCFFTs having tubes of low confinement effectiveness may experience a significant strength loss at the point of transition on their stress-strain curves. Furthermore,it is found that the behavior of HSCFFTs at this region differ from that of normal-strength CFFTs and that it is more sensitive to the effectiveness of a confining tube. Examination of the test results have also lead to a number of important observations on the influence of the key confinement parameters on the development and distribution of the hoop strains on the tubes of CFFTs,which are presented and discussed in the paper.

Keywords: reinforced polymer tubes; confined concrete; seismic performance; composite jackets; columns; cylinders; model; manufacture来源出版物:Journal of Composites For Construction,2013,17(1): 151-161

联系邮箱:Ozbakkaloglu,T; tozbakka@civeng.adelaide.edu.au

被引频次: 30

Multi-stage structural damage diagnosis method based on "energy-damage" theory

Yi,TH; Li,HN; Sun,HM

Abstract: Locating and assessing the severity of damage in large or complex structures is one of the most challenging problems in the field of civil engineering. Considering that the wavelet packet transform(WPT)has the ability to clearly reflect the damage characteristics of structural response signals and the artificial neural network(ANN)is capable of learning in an unsupervised manner and of forming new classes when the structural exhibits change,this paper investigates a multi-stage structural damage diagnosis method by using the WPT and ANN based on "energy-damage" theory,in which,the wavelet packet component energies are first extracted to be damage sensitive feature and then adopted as input into an improved back propagation(BP)neural network model for damage diagnosis in a step by step mode. To validate the efficacy of the presented approach of the damage diagnosis,the benchmark structure of the American Society of Civil Engineers(ASCE)is employed in the case study. The results of damage diagnosis indicate that the method herein is computationally efficient and is able to detect the existence of different damage patterns in the simulated experiment where minor,moderate and severe damages corresponds to involving in the loss of stiffness on braces or the removal bracing in various combinations.

Keywords: artificial neural-networks; algorithm

来源出版物:Smart Structures and Systems,2013,12(3-4): 345-361联系邮箱:Li,HN; hnli@dlut.edu.cn

ENGINEERING ELECTRICAL ELECTRONIC 电气与电子工程

被引频次: 103

Real-Time Implementation of Fault-Tolerant Control Systems With Performance Optimization

Yin,S; Luo,H; Ding,SX

Abstract: In this paper,two online schemes for an integrated design of fault-tolerant control(FTC)systems with application to Tennessee Eastman(TE)benchmark are proposed. Based on the data-driven design of the proposed fault-tolerant architecture whose core is an observer/residual generator based realization of the Youla parameterization of all stabilization controllers,FTC is achieved by an adaptive residual generator for the online identification of the fault diagnosis relevant vectors,and an iterative optimization method for system performance enhancement. The performance and effectiveness of the proposed schemes are demonstrated through the TE benchmark model. Keywords: diagnosis; drives; identification; strategies; design

来源出版物:IEEE Transactions on Industrial Electronics,2014,61(5): 2402-2411联系邮箱:Yin,S; shen.yin2011@googlemail.com

被引频次: 80

Massive MIMO in the UL/DL of Cellular Networks: How Many Antennas Do We Need?

Hoydis,J; ten Brink,S; Debbah,M

Abstract: We consider the uplink(UL)and downlink(DL)of non-cooperative multi-cellular time-division duplexing(TDD)systems,assuming that the number N of antennas per base station(BS)and the number K of user terminals(UTs)per cell are large. Our system model accounts for channel estimation,pilot contamination,and an arbitrary path loss and antenna correlation for each link. We derive approximations of achievable rates with several linear precoders and detectors which are proven to be asymptotically tight,but accurate for realistic system dimensions,as shown by simulations. It is known from previous work assuming uncorrelated channels,that as N -> infinity while K is fixed,the system performance is limited by pilot contamination,the simplest precoders/detectors,i.e.,eigenbeamforming(BF)and matched filter(MF),are optimal,and the transmit power can be made arbitrarily small. We analyze to which extent these conclusions hold in the more realistic setting where N is not extremely large compared to K. In particular,we derive how many antennas per UT are needed to achieve eta% of the ultimate performance limit with infinitely many antennas and how many more antennas are needed with MF and BF to achieve the performance of minimum mean-square error(MMSE)detection and regularized zero-forcing(RZF),respectively.

Keywords: multiuser mimo; channel; wireless; systems

来源出版物:IEEE Journal on Selected Areas in Communications,2013,31(2): 160-171

联系邮箱:Hoydis,J; jakob.hoydis@alcatel-lucent.com

被引频次: 79

Adaptive Sliding-Mode Control for Nonlinear Active Suspension Vehicle Systems Using T-S Fuzzy Approach

Li,HY; Yu,JY; Hilton,C; et al.

Abstract: This paper deals with the adaptive sliding-mode control problem for nonlinear active suspension systems via the Takagi-Sugeno(T-S)fuzzy approach. The varying sprung and unsprung masses,the unknown actuator nonlinearity,and the suspension performances are taken into account simultaneously,and the corresponding mathematical model is established. The T-S fuzzy system is used to describe the original nonlinear system for the control-design aim via the sector nonlinearity approach. A sufficient condition is proposed for the asymptotical stability of the designing sliding motion. An adaptive sliding-mode controller is designed to guarantee the reachability of the speci-fied switching surface. The condition can be converted to the convex optimization problems. Simulation results for a half-vehicle active suspension model are provided to demonstrate the effectiveness of the proposed control schemes.

Keywords: h-infinity control; time-delay; car model; feedback; design

来源出版物:IEEE Transactions on Industrial Electronics,2013,60(8): 3328-3338联系邮箱:Li,HY; lihongyi2009@gmail.com

被引频次: 79

Semipolar(20(2)over-bar(1)over-bar)InGaN/GaN Light-Emitting Diodes for High-Efficiency Solid-State Lighting

Feezell,DF; Speck,JS; DenBaars,SP; et al.

Abstract: This work examines the effects of polarization-related electric fields on the energy band diagrams,wavelength shift,wave function overlap,and efficiency droop for InGaN quantum wells on various crystal orientations,including polar(0001)(c-plane),semipolar(20(2)over bar1),semipolar(20(2)over bar(1)over bar),and non-polar(10(1)over bar0)(m-plane). Based on simulations,we show that the semipolar(20(2)over bar(1)over bar)orientation exhibits excellent potential for the development of high-efficiency,low-droop light-emitting diodes(LEDs). We then present recent advancements in crystal growth,optical performance,and thermal performance of semipolar(20(2)over bar(1)over bar)LEDs. Finally,we demonstrate a low-droop,high-efficiency single-quantum-well blue semipolar(20(2)over bar(1)over bar)LED with an external quantum efficiency of more than 50% at 100 A/cm2.

Keywords: quantum-wells; semiconductors; polarization

来源出版物:Journal of Display Technology,2013,9(4): 190-198联系邮箱:Feezell,DF; dfeezell@unm.edu

被引频次: 77

A Novel Control Design on Discrete-Time Takagi-Sugeno Fuzzy Systems With Time-Varying Delays

Su,XJ; Shi,P; Wu,LG; et al.

Abstract: This paper focuses on analyzing a new model transformation of discrete-time Takagi-Sugeno(T-S)fuzzy systems with time-varying delays and applying it to dynamic output feedback(DOF)controller design. A new comparison model is proposed by employing a new approximation for time-varying delay state,and then,a delay partitioning method is used to analyze the scaled small gain of this comparison model. A sufficient condition on discrete-time T-S fuzzy systems with time-varying delays,which guarantees the corresponding closed-loop system to be asymptotically stable and has an induced 2 disturbance attenuation performance,is derived by employing the scaled small-gain theorem. Then,the solvability condition for the induced 2 DOF control is also established,by which the DOF controller can be solved as linear matrix inequality optimization problems. Finally,examples are provided to illustrate the effectiveness of the proposed approaches.

Keywords: output-feedback control; h-infinity control; stability analysis; nonlinear-systems; lmi approach; fault-detection; model; stabilization

来源出版物:Ieee Transactions on Fuzzy Systems,2013,21(4): 655-671联系邮箱:Su,XJ; suxiaojie1985@gmail.com

ENGINEERING ENVIRONMENTAL 环境工程

被引频次: 122

Characterising performance of environmental models

Bennett,ND; Croke,BFW; Guariso,G; et al.

Abstract: In order to use environmental models effectively for management and decision-making,it is vital to establish an appropriate level of confidence in their performance. This paper reviews techniques available across various fields for characterising the performance of environmental models with focus on numerical,graphical and qualitative methods. General classes of direct value comparison,coupling real and modelled values,preserving data patterns,indirect metrics based on parameter values,and data transformations are discussed. In practice environmental modelling requires the use and implementation of workflows that combine several methods,tailored to the model purpose and dependent upon the data and information available. A five-step procedure for performance evaluation of models is suggested,with the key elements including:(i)(re)assessment of the model's aim,scale and scope;(ii)characterisation of the data for calibration and testing;(iii)visual and other analysis to detect under- or non-modelled behaviour and to gain an overview of overall performance;(iv)selection of basic performance criteria; and(v)consideration of more advanced methods to handle problems such as systematic divergence between modelled and observed values.

Keywords: rainfall-runoff models; sensitivity-analysis; hydrological models; parameter-estimation; ecological models; standardized assessment; simulation-models; quality-assurance; dispersion model; wavelet analysis

来源出版物:Environmental Modelling & Software,2013,40: 1-20联系邮箱:Jakeman,AJ; tony.jakeman@anu.edu.au

被引频次: 76

Novel visible-light-driven AgX/graphite-like C3N4(X=Br,I)hybrid materials with synergistic photocatalytic activity

Xu,H; Yan,J; Xu,YG; et al.

Abstract: Novel visible-light-driven AgX/g-C3N4(X = Br,I)hybrid materials were synthesized by the facile water bath method. The AgX/g-C3N4hybrid materials were characterized by X-ray diffraction(XRD),energy dispersive X-ray spectrometer(EDS),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),UV-vis diffuse reflectance spectroscopy(DRS),photoluminescence(PL),Fourier transform infrared spectra(FTIR),Raman and the special surface area. The XRD,EDS,TEM,FTIR,Raman and XPS analyses indicated that AgX nanoparticles were evenly distributed on the surface of g-C3N4and the heterostructures were formed. The photocatalytic activity of the AgX/g-C3N4hybrid materials was evaluated using methyl orange as a target organic pollutant. The as-prepared AgX/g-C3N4hybrid materials displayed much higher photocatalytic activity than the pure g-C3N4and AgX nanoparticles. After the introduction of AgX nanoparticles,the photocurrent of the AgBr/g-C3N4and AgI/g-C3N4hybrid materials was found to increase by 21 and 8 times than that of the pure g-C3N4,respectively. The increased photocatalytic activity of the AgX/g-C3N4hybrid materials was attributed to the synergic effect between g-C3N4and AgX,which included the optical property,the better dispersion and the small size. A photocatalytic mechanism and the kinetics of AgX/g-C3N4hybrid materials were also proposed.

Keywords: graphitic carbon nitride; one-pot synthesis; methyl-orange; composite photocatalysts; electronic-structure; selective oxidation;hydrogen-production; particle-size; gas-phase; degradation

来源出版物:Applied Catalysis B-environmental,2013,129: 182-193联系邮箱:Li,HM; lihm@ujs.edu.cn

被引频次: 65

Urban wastewater treatment plants as hotspots for the release of antibiotics in the environment: A review

Michael,I; Rizzo,L; McArdell,CS; et al.

Abstract: Urban wastewater treatment plants(UWTPs)are among the main sources of antibiotics' release into various compartments of the environment worldwide. The aim of the present paper is to critically review the fate and removal of various antibiotics in wastewater treatment,focusing on different processes(i.e. biological processes,advanced treatment technologies and disinfection)in view of the current concerns related to the induction of toxic effects in aquatic and terrestrial organisms,and the occurrence of antibiotics that may promote the selection of antibiotic resistance genes and bacteria,as reported in the literature. Where available,estimations of the removal of antibiotics are provided along with the main treatment steps. The removal efficiency during wastewater treatment processes varies and is mainly dependent on a combination of antibiotics' physicochemical properties and the operating conditions of the treatment systems. As a result,the application of alternative techniques including membrane processes,activated carbon adsorption,advanced oxidation processes(AOPs),and combinations of them,which may lead to higher removals,may be necessary before the final disposal of the effluents or their reuse for irrigation or groundwater recharge.

Keywords: tandem mass-spectrometry; advanced oxidation processes; solid-phase extraction; sewage-treatment plant; photo-fenton process; fluoroquinolone antibacterial agents; endocrine disrupting compounds; activated-sludge treatment; personal care products; aquatic environment

来源出版物:Water Research,2013,47(3): 957-995联系邮箱:Fatta-Kassinos,D; dfatta@ucy.ac.cy

被引频次: 50

Facets coupling of BiOBr-g-C3N4composite photocatalyst for enhanced visible-light-driven photocatalytic activity

Ye,LQ; Liu,JY; Jiang,Z; et al.

Abstract: BiOBr-g-C3N4inorganic-organic composite photocatalysts were synthesized by a one-step chemical bath method at low temperature and characterized by X-ray diffraction patterns(XRD),Fourier transform infrared(FT-IR),thermo gravimetric(TG),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM)and UV-vis diffuse reflectance spectra(DRS). The BiOBr-g-C3N4composite showed much higher visible-light-driven(VLD)photocatalytic activity than pure g-C3N4and BiOBr for rhodamine B(RhB)degradation. The photocatalytic mechanism analysis revealed that the interreaction between BiOBr and g-C3N4is a kind of facet coupling between BiOBr-{0 0 1} and g-C3N4-{0 0 2}. The active species trapping and quantification experiments indicated that the photoinduced charges transfer between these facets resulted in the efficient charge separation.

Keywords: graphite-like C3N4; acid orange 7; biox x; degradation; surface; carbon; Br; Cl; nanosheets; photoreactivity

来源出版物:Applied Catalysis B-environmental,2013,142: 1-7联系邮箱:Zan,L; irlab@whu.edu.cn

被引频次: 49

Recycling of rare earths: a critical review

Binnemans,K; Jones,PT; Blanpain,B; et al.

Abstract: The rare-earth elements(REEs)are becoming increasingly important in the transition to a green economy,due to their essential role in permanent magnets,lamp phosphors,catalysts,rechargeable batteries etc. With China presently producing more than 90% of the global REE output and its increasingly tight export quota,the rest of the world is confronted with a REE supply risk. Mining companies are now actively seeking new exploitable REE deposits while some old mines are being reopened. Because of the absence of economical and/or operational primary deposits on their territory,many countries will have to rely on recycling of REEs from pre-consumer scrap,industrial residues and REE-containing End-of-Life products. REE recycling is also recommended in view of the so-called "balance problem". For instance,primary mining of REE ores for neodymium generates an excess of the more abundant elements,lanthanum and cerium. Therefore,recycling of neodymium can reduce the total amount of REE ores that need to be extracted. Despite a vast,mostly lab-scale research effort on REE recycling,up to 2011 less than 1% of the REEs were actually recycled. This is mainly due to inefficient collection,technological problems and,especially,a lack of incentives. A drastic improvement in the recycling of REEs is,therefore,an absolute necessity. This can only be realized by developing efficient,fully integrated recycling routes,which can take advantage of the rich REE recycling literature. This paper provides an overview of this literature,with emphasis on three main applications: permanent magnets,nickel metal hydride batteries and lamp phosphors. The state of the art in preprocessing of End-of-Life materials containing REEs and the final REE recovery is discussed in detail. Both pyrometallurgical and hydrometallurgical routes for REE separation from non-REE elements in the recycled fractions are reviewed. The relevance of Life Cycle Assessment(LCA)for REE recycling is emphasized. The review corroborates that,in addition to mitigating the supply risk,REE recycling can reduce the environmental challenges associated with REE mining and processing.

Keywords: chemical-vapor transport; glass slag method; metal-hydride batteries; b sintered magnet; compact fluorescent lamps; isotropic bonded magnets; nimh spent batteries; in-use stocks; hydrometallurgical process; mutual separation

来源出版物:Journal of Cleaner Production,2013,51: 1-22联系邮箱:Binnemans,K; Koen.Binnemans@chem.kuleuven.be

ENGINEERING GEOLOGICAL 地质工程

被引频次: 24

The signature of shear-induced anisotropy in granular media

Guo,N; Zhao,JD

Abstract: This paper presents a micro-mechanical study on the characteristics of shear-induced anisotropy in granular media. Based on three-dimensional Discrete Element Method(DEM)simulations,the distinct features associated with the evolution of internal granular structure and different anisotropy sources during drained/undrained shearing of granular samples are carefully examined. The study finds that static liquefaction occurs when the geometrical anisotropy in a sample dominates the mechanical anisotropy in the overall shear strength,and the weak force network features an exceptionally high proportion of sliding contacts and develops certain degree of anisotropy. Phase transformation corresponds to a transitional,unstable state associated with a dramatic change in both coordination number and the proportion of sliding contacts in all contacts. The critical state in a granular material is always associated with a highly anisotropic fabric structure wherein both the critical void ratio and critical fabric anisotropy are uniquely related to the mean effective stress. The relations provide a more comprehensive definition for the critical state in granular media with proper reference to the critical fabric anisotropy.

Keywords: critical-state; material behavior; stress; deformation; simulations; sand; liquefaction; assemblies; failure; scales

来源出版物:Computers and Geotechnics,2013,47: 1-15联系邮箱:Zhao,JD; jzhao@ust.hk

被引频次: 17

Permeability evolution during progressive deformation of intact coal and implications for instability in underground coal seams

Wang,SG; Elsworth,D; Liu,JS

Abstract: We report measurements of deformation,strength and permeability evolution during triaxial compression of initially intact coals. Permeability is continuously measured by the constant pressure differential method,together with axial and volumetric strains for both water(H2O)and strongly adsorbing carbon dioxide(CO2)gas. Strength and Young's modulus increase with increasing confining stress and permeability is hysteretic in the initial reversible deformation regime. As deviatoric stress and strain increase,permeability first decreases as pre-existing cleats close,and then increases as new vertical dilatant microcracks are generated. Post-peak strength the permeability suddenly increases by 3-4 orders-of-magnitude. During loading,the inflection point where permeability begins to increase occurs earlier than the turning point of volumetric strain,which may be explained by the competing processes of axial crack opening and closure of oblique and transverse cracks. The generation of these vertical microcracks does not enhance gas migration in the horizontal direction but will ac-celerate the rate of gas desorption and weaken the coal.

Based on this mechanistic observation,we propose a process-based model for bursting in underground coal seams. Horizontal and vertical stresses redistribute ahead of the mining-face immediately after the excavation and influence pore pressure,permeability,and desorption rate. Due to this redistribution,the zone closest to the mining-face may experience tensile failure. Interior to this zone a region may develop with gas overpressures induced by desorption and this may contribute to the occurrence of coal and gas outbursts. Beyond this,an overstressed zone may initiate shear failure driven by gas pressures if the desorption rate outstrips the rate of drainage. We discuss the implications of this on the instability of coal seams to CO2injection and the potential for induced fault slip.

Keywords: mining-induced stress; gas outbursts; carbon-dioxide; methane recovery; mines; pressure; CO2; sequestration; compression;adsorption

来源出版物:International Journal of Rock Mechanics and Mining Sciences,2013,58: 34-45

联系邮箱:Wang,SG; shugangwang@gmail.com

被引频次: 14

Landslides triggered by slipping-fault-generated earthquake on a plateau: an example of the 14 April 2010,Ms 7.1,Yushu,China earthquake

Xu,C; Xu,XW; Yu,GH

Abstract: On 14 April 2010 at 07:49(Beijing time),a catastrophic earthquake with Ms 7.1 struck Yushu County,Qinghai Province,China. A total of 2,036 landslides were interpreted from aerial photographs and satellite images,verified by selected field checking. These landslides cover about a total area of 1.194 km2. The characteristics and failure mechanisms of these landslides are presented in this paper. The spatial distribution of the landslides is evidently strongly controlled by the locations of the main co-seismic surface fault ruptures. The landslides commonly occurred close together. Most of the landslides are small; there were only 275 individual landslide(13.5 % of the total number)surface areas larger than 1000 m2. The landslides are of various types. They are mainly shallow,disrupted landslides,but also include rock falls,deep-seated landslides,liquefaction-induced landslides,and compound landslides. Four types of factors are identified as contributing to failure along with the strong ground shaking: natural excavation of the toes of slopes,which mean erosion of the base of the slope,surface water infiltration into slopes,co-seismic fault slipping at landslide sites,and delayed occurrence of landslides due to snow melt or rainfall infiltration at sites where slopes were weakened by the co-seismic ground shaking. To analyze the spatial distribution of the landslides,the landslide area percentage(LAP)and landslide number density(LND)were compared with peak ground acceleration(PGA),distance from co-seismic main surface fault ruptures,elevation,slope gradient,slope aspect,and lithology. The results show landslide occurrence is strongly controlled by proximity to the main surface fault ruptures,with most landslides occurring within 2.5 km of such ruptures. There is no evident correlation between landslide occurrences and PGA. Both LAP and LND have strongly positive correlations with slope gradient,and additionally,sites at elevations between 3800 and 4000 m are relatively susceptible to landslide occurrence; as are slopes with northeast,east,and southeast slope aspects. Q(4)al-pl,N,and T-3 kn(1)have more concentrated landslide activity than others. This paper provides a detailed inventory map of landslides triggered by the 2010 Yushu earthquake for future seismic landslide hazard analysis and also provides a study case of characteristics,failure mechanisms,and spatial distribution of landslides triggered by slipping-fault generated earthquake on a plateau.

Keywords: 2008 wenchuan earthquake; kashmir earthquake; prefecture earthquake; statistical approach; niigata prefecture; 1994 northridge; mid-niigata; susceptibility; japan; region

来源出版物:Landslides,2013,10(4): 421-431联系邮箱:Xu,XW; xuchong@ies.ac.cn

被引频次: 14

The Brazilian Disc Test for Rock Mechanics Applications: Review and New Insights

Li,DY; Wong,LNY

Abstract: The development of the Brazilian disc test for determining indirect tensile strength and its applications in rock mechanics are reviewed herein. Based on the history of research on the Brazilian test by analytical,experimental,and numerical approaches,three research stages can be identified. Most of the early studies focused on the tensile stress distribution in Brazilian disc specimens,while ignoring the tensile strain distribution. The observation of different crack initiation positions in the Brazilian disc has drawn a lot of research interest from the rock mechanics community. A simple extension strain criterion was put forward by Stacey(Int J Rock Mech Min Sci Geomech Abstr 18(6):469-474,1981)to account for extension crack initiation and propagation in rocks,although this is not widely used. In the present study,a linear elastic numerical model is constructed to study crack initiation in a 50-mm-diameter Brazilian disc using FLAC(3D). The maximum tensile stress and the maximum tensile strain are both found to occur about 5 mm away from the two loading points along the compressed diameter of the disc,instead of at the center of the disc surface. Therefore,the crack initiation point of the Brazilian test for rocks may be located near the loading point when the tensile strain meets the maximum extension strain criterion,but at the surface center when the tensile stress meets the maximum tensile strength criterion.

Keywords: tensile-strength; diametral compression; boundary-conditions; fracture-toughness; elastic-modulus; stress-field; failure; size;specimen; friction

来源出版物:Rock Mechanics and Rock Engineering,2013,46(2): 269-287联系邮箱:Wong,LNY; diyuan.li@csu.edu.cn

被引频次: 12

How to assess landslide activity and intensity with Persistent Scatterer Interferometry(PSI): the PSI-based matrix approach

Cigna,F; Bianchini,S; Casagli,N

Abstract: We provide a step-by-step analysis and discussion of the 'PSI-based matrix approach',a methodology employing ground deformation velocities derived through Persistent Scatterer Interferometry(PSI)for the assessment of the state of activity and intensity of extremely to very slow landslides. Two matrices based on PSI data are designed respectively for landslides already mapped in preexisting inventories and for newly identified phenomena. Conversely,a unique intensity scale is proposed indiscriminately for both. Major influencing factors of the approach are brought to light by the application in the 14 km2area of Verbicaro,in Northern Calabria(Italy). These include lack of PSI data within the landslide boundaries,temporal coverage of the available estimates,and need of field checks as well as the operative procedures to set the activity and intensity thresholds. For the area of Verbicaro,we exploit 1992-2011 PSI data from ERS1/2 and RADARSAT1/2 satellites,projecting them along the maximum slope directions. An activity threshold of±5 mm/year is determined by applying the average projection factor of local slopes to the PSI data precision. The intensity threshold between extremely and very slow phenomena(16 mm/year)is reduced by similar to 20 % to account for temporal and spatial averages being applied to attribute representative velocities to each landslide. The methodology allows assessing the state of activity and the intensity for 13 of the 24 landslides premapped in the 2007 inventory and for two newly identified phenomena. Current limitations due to characteristics and spatial coverage of PSI data are critically tackled within the discussion,jointly with respective implications.

Keywords: permanent scatterers; sar interferometry; northern calabria; hazard evaluation

来源出版物:Landslides,2013,10(3): 267-283联系邮箱:Cigna,F; fcigna@bgs.ac.uk

ENGINEERING INDUSTRIAL 工业工程

被引频次: 78

Network-Induced Constraints in Networked Control Systems-A Survey

Zhang,LX; Gao,HJ; Kaynak,O

Abstract: Networked control systems(NCSs)have,in recent years,brought many innovative impacts to control systems. However,great challenges are also met due to the network-induced imperfections. Such network-induced imperfections are handled as various constraints,which should appropriately be considered in the analysis and design of NCSs. In this paper,the main methodologies suggested in the literature to cope with typical network-induced constraints,namely time delays,packet losses and disorder,time-varying transmission intervals,competition of multiple nodes accessing networks,and data quantization are surveyed; the constraints suggested in the literature on the first two types of constraints are updated in different categorizing ways; and those on the latter three types of constraints are extended.

Keywords: limited information feedback; input-output stability; to-state stability; h-infinity control; linear-systems; predictive control;special-issue; communication delays; nonlinear-systems; packet drop

来源出版物:IEEE Transactions on Industrial Informatics,2013,9(1): 403-416联系邮箱:Zhang,LX; lixianzhango@hit.edu.cn

被引频次: 62

H-infinity Step Tracking Control for Networked Discrete-Time Nonlinear Systems With Integral and Predictive Actions

Zhang,H; Shi,Y; Liu,MX

Abstract: This paper investigates the step tracking control problem for discrete-time nonlinear systems in a networked environment with a limited capacity. The nonlinear system is represented by a Takagi-Sugeno(T-S)fuzzy system,and a network-induced delay is incorporated in the modeling of the connection link. In order to compensate for the network link effects and eliminate the tracking error,we employ some techniques mainly used in the predictive control and the integral control. Moreover,a quadratic cost function which includes terms related to the performance of the system and the actuating capacity is used. We assume that the lumped network-induced delay lies within a known set,and that the occurrence probability for each element in the set is known a priori. Then,the delay information will be incorporated into the delay-dependent tracking controllers. The parameters for the tracking controller are derived by solving an optimization problem. A networked inverted pendulum is used to illustrate the efficacy of the proposed design method.

Keywords: jump linear-systems; communication channels; varying delays; stabilization

来源出版物:IEEE Transactions on Industrial Informatics,2013,9(1): 337-345联系邮箱:Zhang,H; huizhang285@gmail.com

被引频次: 59

A Survey on Smart Grid Potential Applications and Communication Requirements

Gungor,VC; Sahin,D; Kocak,T; et al.

Abstract: Information and communication technologies(ICT)represent a fundamental element in the growth and performance of smart grids. A sophisticated,reliable and fast communication infrastructure is,in fact,necessary for the connection among the huge amount of distributed elements,such as generators,substations,energy storage systems and users,enabling a real time exchange of data and information necessary for the management of the system and for ensuring improvements in terms of efficiency,reliability,flexibility and investment return for all those involved in a smart grid: producers,operators and customers. This paper overviews the issues related to the smart grid architecture from the perspective of potential applications and the communications requirements needed for ensuring performance,flexible operation,reliability and economics.

Keywords: renewable-energy-sources; system automation; power-systems; networks; architecture; challenges; opportunities; management;operation; future

来源出版物:IEEE Transactions on Industrial Informatics,2013,9(1): 28-42联系邮箱:Gungor,VC; cagri.gungor@bahcesehir.edu.tr

被引频次: 51

An Overview of Recent Progress in the Study of Distributed Multi-Agent Coordination

Cao,YC; Yu,WW; Ren,W; et al.

Abstract: This paper reviews some main results and progress in distributed multi-agent coordination,focusing on papers published in major control systems and robotics journals since 2006. Distributed coordination of multiple vehicles,including unmanned aerial vehicles,unmanned ground vehicles,and unmanned underwater vehicles,has been a very active research subject studied extensively by the systems and control community. The recent results in this area are categorized into several directions,such as consensus,formation control,optimization,and estimation. After the review,a short discussion section is included to summarize the existing research and to propose several promising research directions along with some open problems that are deemed important for further investigations.

Keywords: multivehicle cooperative control; planar collective motion; mobile sensor networks; consensus algorithms; switching-networks;vehicle formations; gossip algorithms; tracking control; time-delays; systems

来源出版物:IEEE Transactions on Industrial Informatics,2013,9(1): 427-438

被引频次: 39

Sensor Networks With Random Link Failures: Distributed Filtering for T-S Fuzzy Systems

Su,XJ; Wu,LG; Shi,P

Abstract: The paper is concerned with the problem of distributed fuzzy filter design for a class of sensor networks described by discrete-time T-S fuzzy systems with time-varying delays and multiple probabilistic packet losses. In sensor network,each individual sensor can receive not only its own measurement but also its neighboring sensors' measurements according to the interconnection topology to estimate the system states. Our attention is focused on the design of distributed fuzzy filters to guarantee the filtering error dynamic system to be mean-square asymptotically stable with an average performance. Sufficient conditions for the obtained filtering error dynamic system are proposed by applying an comparison model and the scaled small gain theorem. Based on the measurements and estimates of the system states and its neighbors for each sensor,the solution of the parameters of the distributed fuzzy filters is characterized in terms of the feasibility of a convex optimization problem. Finally,an illustrative example is provided to illustrate the effectiveness of the proposed approaches in sensor networks.

Keywords: time-varying delay; design; fault

来源出版物:IEEE Transactions on Industrial Informatics,2013,9(3): 1739-1750联系邮箱:Su,XJ; suxiaojie1985@gmail.com

ENGINEERING MANUFACTURING 制造工程

被引频次: 41

Cuckoo search algorithm for the selection of optimal machining parameters in milling operations

Yildiz,AR

Abstract: In this research,a new optimization algorithm,called the cuckoo search algorithm(CS)algorithm,is introduced for solving manufacturing optimization problems. This research is the first application of the CS to the optimization of machining parameters in the literature. In order to demonstrate the effectiveness of the CS,a milling optimization problem was solved and the results were compared with those obtained using other well-known optimization techniques like,ant colony algorithm,immune algorithm,hybrid immune algorithm,hybrid particle swarm algorithm,genetic algorithm,feasible direction method,and handbook recommendation. The results demonstrate that the CS is a very effective and robust approach for the optimization of machining optimization problems.

Keywords: genetic algorithm; optimization problems; design optimization; immune algorithm

来源出版物:International Journal of Advanced Manufacturing Technology,2013,64(1-4): 55-61

联系邮箱:Yildiz,AR; aliriza.yildiz@btu.edu.tr

被引频次: 32

Adaptive Backstepping Control for Active Suspension Systems With Hard Constraints

Sun,WC; Gao,HJ; Kaynak,O

Abstract: This paper proposes an adaptive backstepping control strategy for vehicle active suspensions with hard constraints. An adaptive backstepping controller is designed to stabilize the attitude of vehicle and meanwhile improve ride comfort in the presence of parameter uncertainties,where suspension spaces,dynamic tire loads,and actuator saturations are considered as time-domain constraints. In addition to spring nonlinearity,the piecewise linear behavior of the damper,which has different damping rates for compression and extension movements,is taken into consideration to form the basis of accurate control. Furthermore,a reference trajectory is planned to keep the vertical and pitch motions of car body to stabilize in predetermined time,which helps adjust accelerations accordingly to high or low levels for improving ride comfort. Finally,a design example is shown to illustrate the effectiveness of the proposed control law.

Keywords: h-infinity control; vibration control; vehicle; design; delay

来源出版物:IEEE-ASME Transactions on Mechatronics,2013,18(3): 1072-1079联系邮箱:Sun,WC; 1984sunweichao@gmail.com

被引频次: 29

A taxonomy of line balancing problems and their solution approaches

Battaia,O; Dolgui,A

Abstract: Line balancing belongs to a class of intensively studied combinatorial optimization problems known to be NP-hard in general. For several decades,the core problem originally introduced for manual assembly has been extended to suit robotic,machining and disassembly contexts. However,despite various industrial environments and line configurations,often quite similar or even identical mathematical models have been developed. The objective of this survey is to analyze recent research on balancing flow lines within many different industrial contexts in order to classify and compare the means for input data modelling,constraints and objective functions used. This survey covers about 300 studies on line balancing problems. Particular attention is paid to recent publications that have appeared in 2007-2012 to focus on new advances in the state-of-the-art.

Keywords: 2-sided assembly-line; ant colony optimization; simulated annealing algorithm; dependent setup times; particle swarm optimization; goal programming approach; hybrid genetic algorithm; decision-support-system; secondary feeder lines; sheltered work centers

来源出版物:International Journal of Production Economics,2013,142(2): 259-277联系邮箱:Battaia,O; battaia@emse.fr

被引频次: 19

High-Accuracy Tracking Control of Hydraulic Rotary Actuators With Modeling Uncertainties

Yao,JY; Jiao,ZX; Ma,DW; et al.

Abstract: Structured and unstructured uncertainties are the main obstacles in the development of advanced controllers for high-accuracy tracking control of hydraulic servo systems. For the structured uncertainties,nonlinear adaptive control can be employed to achieve asymptotic tracking performance. But modeling errors,such as nonlinear frictions,always exist in physical hydraulic systems and degrade the tracking accuracy. In this paper,a robust integral of the sign of the error controller and an adaptive controller are synthesized via backstepping method for motion control of a hydraulic rotary actuator. In addition,an experimental internal leakage model of the actuator is built for precise model compensation. The proposed controller accounts for not only the structured uncertainties(i.e.,parametric uncertainties),but also the unstructured uncertainties(i.e.,nonlinear frictions). Furthermore,the controller theoretically guarantees asymptotic tracking performance in the presence of various uncertainties,which is very important for high-accuracy tracking control of hydraulic servo systems. Extensive comparative experimental results are obtained to verify the high-accuracy tracking performance of the proposed control strategy.

Keywords: adaptive robust-control; electrohydraulic load simulator; friction compensation; nonlinear-systems; motion control; servo systems; force control; manipulators; observer; tools

来源出版物:IEEE-ASME Transactions on Mechatronics,2014,19(2): 633-641联系邮箱:Yao,JY; jerryyao.buaa@gmail.com

被引频次: 19

Critical Human Factor Evaluation of Knowledge Sharing Intention in Taiwanese Enterprises

Chen,CW; Chang,ML; Tseng,CP; et al.

Abstract: Knowledge management(KM)is important in the Taiwan business world. Only 0.1% of SMEs,however,have been guided by the Small and Medium Enterprise Administration(SMEA)to introduce knowledge management from 1993 through 2008. The populationof KM-implementing SMEs is low. The climate of knowledge sharing has been recognized as the critical factor to successful KM. According to the research results obtained in this study,relation-based motivation is positively related to one's intention to share knowledge. Individual workers can have increased relation-based motivation to become leaders of SMEs building the culture of interpersonal trust and offering group-based reward mechanisms in an organization. This research can help business managers to identify the motivational elements that can encourage investment and propose pragmatic suggestions for introducing initiatives to reinvigorate the number of SMEs implementing KM in Taiwan.

Keywords: management-systems; communities; performance; stickiness; trust; firm

来源出版物:Human Factors and Ergonomics in Manufacturing & Service Industries,2013,23(2): 95-106

联系邮箱:Chen,CW; chengwu@mail.nkmu.edu.tw

ENGINEERING MARINE 船舶工程

被引频次: 12

Perturbation of dispersive shallow water waves

Razborova,P; Triki,H; Biswas,A

Abstract: This paper addresses the dynamics of dispersive shallow water wave that is governed by the Rosenau-KdV equation with power law nonlinearity. The singular 1-soliton solution is derived by the ansatz method. Subsequently,the soliton perturbation theory is applied to obtain the adiabatic parameter dynamics of the water waves. Finally,the integration of the perturbed Rosenau-KdV equation is obtained by the ansatz method as well as the semi-inverse variational principle.

Keywords: power-law nonlinearity; solitary waves; rosenau-kdv; solitons; equation

来源出版物:Ocean Engineering,2013,63: 1-7联系邮箱:Biswas,A; biswas.anjan@gmail.com

被引频次: 9

Statistical modelling of extreme ocean environments for marine design: A review

Jonathan,P; Ewans,K

Abstract: We review aspects of extreme value modelling relevant to characterisation of ocean environments and the design of marine structures,summarising basic concepts,modelling with covariates and multivariate modelling(including conditional and spatial extremes). We outline Bayesian inference for extremes and reference software resources for extreme value modelling. Extreme value analysis is inherently different to other empirical modelling,in that estimating the tail(rather than the body)of a distribution from a sample of data,and extrapolation beyond the sample(rather than interpolation within)is demanded. Intuition accumulated from other areas of empirical modelling can be misleading. Careful consideration of the effects of sample size,measurement scale,threshold selection and serial dependence,associated uncertainties and implications of choices made is essential. Incorporation of covariate effects when necessary improves inference. Suitable tools(e.g. based on additive models,splines,random fields,spatial processes)have been developed,but their use is restricted in general to academia. Effective modelling of multivariate extremes will improve the specification of design conditions for systems whose response cannot be easily characterised in terms of one variable. Approaches such as the conditional extremes model are easily implemented,and provide generalisations of existing marine design approaches(e.g. for primary and associated variables). Software is available,but again generally only for academic use. Modelling spatial dependence rigourously will provide single extreme value models applicable to spatial neighbourhoods including complete ocean basins,avoiding the need for procedures such as site pooling. Indeed,once the model is established,the metocean engineer may not ever need to perform further extreme value analysis for that basin in principle. Spatial extremes is an area of active research in the statistics community. A limited number of appropriate models have been deployed(e.g. for precipitation,temperature and metocean applications). Software is available,but again for specialist use. Bayesian inference provides a consistent framework for inference and is rapidly becoming the standard approach in academia. It appears inevitable that,in time,Bayesian inference will also be regarded as the standard in ocean engineering applications. Implementation of Bayesian methods requires some expertise. Software is available,but again generally only used by statistical specialists.

Keywords: significant wave height; max-stable processes; sea storm severity; value distributions; bayesian-inference; spatial extremes;time-series; wind speeds; measurement scale; order-statistics

来源出版物:Ocean Engineering,2013,62: 91-109联系邮箱:Jonathan,P; philip.jonathan@shell.com

被引频次: 6

Assessing the China Sea wind energy and wave energy resources from 1988 to 2009

Zheng,CW; Pan,J; Li,JX

Abstract: In this study,the wave field in the China Sea was simulated over the period from 1988 to 2009 using the third-generation wave model WAVEWATCH-III(WW3),with Cross-Calibrated,Multi-Platform(CCMP)wind field as the driving field. The China Sea wind energy density and wave energy density were calculated using the CCMP wind and WW3 model simulation results. The China Sea windenergy and wave energy resource were analyzed,synthetically considering the value of energy density,probability of exceedance of energy density level,exploitable wind speed and exploitable significant wave height(SWH),the stability of energy density,total storage and exploitable storage of energy resources,thus providing the guidance for the location of wind and wave power plants. Our results show that most of the China Sea contains abundant wave energy and offshore wind energy resources,with wind energy density above 150 W/m2,wave energy density above 2 kW/m,high occurrence of exploitable wind and wave energy in large scale waters,wind energy storage above 2×103kW h m-2,wave energy storage above 4×104kW h m-1. The richest area is in the northern South China Sea(wind energy density 350-600 W/m2,wave energy density 10-16 kW/m,wind energy storage 3×103-5×103kW h m-2,wave energy storage 8×104-16×104kW h m-1),followed by southern South China Sea and the East China Sea(wind energy density 150-450 W/m2,wave energy density 4-12 kW/m,wind energy storage 2×103-4×103kW h m-2,wave energy storage 4×104-12×104kW h m-1). The Yellow Sea and Bohai Sea resources are relatively poorer(wind energy density below 300 W/m2,wave energy density below 4 kW/m,wind energy storage below 2.5×103kW h m-2,wave energy storage below 6 x 104kW h m-1).

来源出版物:Ocean Engineering,2013,65: 39-48联系邮箱:Zheng,CW; zhengzhang.xia@163.com

被引频次: 6

A Fast SINS Initial Alignment Scheme for Underwater Vehicle Applications

Li,WL; Wu,WQ; Wang,JL; et al.

Abstract: To achieve high Strapdown Inertial Navigation System(SINS)alignment accuracy within a short period of time is still a challenging issue for underwater vehicles. In this paper,a new SINS initial alignment scheme aided by the velocity derived from Doppler Velocity Log(DVL)is proposed to solve this problem. In the stage of the coarse alignment,the velocity of DVL is employed to reduce the impact of the linear motion. With a backtracking framework,the fine alignment runs with the data recorded during the process of the coarse alignment and thus will speed up the overall alignment process. In addition,by using this new scheme,it is equivalent to length the alignment time for both coarse and fine alignments,so the accuracy of the alignments will be improved. In order to reduce the volume of the data that has to be recorded,a new model for SINS fine alignment is derived in the inertial reference frame which makes it feasible for real time applications. The experimental results are presented for both unaided static and in-motion alignment using DVL aiding. It is clearly shown that the proposed method meets the requirement of SINS alignment for underwater vehicles.

Keywords: kalman filter; system

来源出版物:Journal of Navigation,2013,66(2): 181-198联系邮箱:Li,WL; jinling.wang@unsw.edu.au

被引频次: 6

Hydrodynamic interactions on net panel and aquaculture fish cages: A review

Klebert,P; Lader,P; Gansel,L; et al.

Abstract: Aquaculture is expanding all over the world. The limitations are mainly related to location,water flow,escapees and fish health. The present status of flow hydrodynamics within and around sea-cages is reviewed in this paper,providing a framework for understanding the spatial and temporal variability of key environmental parameters within and outside sea-cages. The paper presents contemporary experiments on drag forces on net panels,model-scale cages,the biological effects of fish,fish movements and fouling as the major topics. It includes also a presentation of different theoretical studies as an attempt to simulate experiments. The accumulated experimental results are sorted out following a gradually increasing scale from the cruciform as a basic element of a net,via net panels to a net cage with solidity and velocity as the main parameters,while the effect of fish and fouling are discussed only at the full-scale level. The compilation is important to understand issues related to the design and mechanics of net cages,taking into account fish behavior in relation to future engineering development within the field of hydrodynamics in aquaculture cage farming. Improved knowledge of water movement through aquaculture cages is critical for future development of efficient and sustainable aquaculture,including a shift toward more exposed locations.

Keywords: salmon salmo-salar; 2 circular-cylinders; scale sea-cages; western mediterranean sea; smolt atlantic salmon; non-uniform gauzes; gravity-type cages; wild fish; swimming behavior; vertical-distribution

来源出版物:Ocean Engineering,2013,58: 260-274联系邮箱:Klebert,P; Pascal.klebert@sintef.no

ENGINEERING MECHANICAL 机械工程

被引频次: 70

Cuckoo search algorithm: a metaheuristic approach to solve structural optimization problems

Gandomi,AH; Yang,XS; Alavi,AH

Abstract: In this study,a new metaheuristic optimization algorithm,called cuckoo search(CS),is introduced for solving structural optimization tasks. The new CS algorithm in combination with L,vy flights is first verified using a benchmark nonlinear constrained optimizationproblem. For the validation against structural engineering optimization problems,CS is subsequently applied to 13 design problems reported in the specialized literature. The performance of the CS algorithm is further compared with various algorithms representative of the state of the art in the area. The optimal solutions obtained by CS are mostly far better than the best solutions obtained by the existing methods. The unique search features used in CS and the implications for future research are finally discussed in detail.

Keywords: particle swarm optimization; engineering design optimization; global optimization; genetic algorithms; constrained optimization; programming-problems; mechanical design; harmony search; differential evolution; levy flights

来源出版物:Engineering With Computers,2013,29(1): 17-35联系邮箱:Gandomi,AH; a.h.gandomi@gmail.com

被引频次: 65

A review of the applications of nanofluids in solar energy

Mahian,O; Kianifar,A; Kalogirou,SA; et al.

Abstract: Utilizing nanofluids as an advanced kind of liquid mixture with a small concentration of nanometer-sized solid particles in suspension is a relatively new field,which is less than two decades old. The aim of this review paper is the investigation of the nanofluids' applications in solar thermal engineering systems. The shortage of fossil fuels and environmental considerations motivated the researchers to use alternative energy sources such as solar energy. Therefore,it is essential to enhance the efficiency and performance of the solar thermal systems. Nearly all of the former works conducted on the applications of nanofluids in solar energy is regarding their applications in collectors and solar water heaters. Therefore,a major part of this review paper allocated to the effects of nanofluids on the performance of solar collectors and solar water heaters from the efficiency,economic and environmental considerations viewpoints. In addition,some reported works on the applications of nanofluids in thermal energy storage,solar cells,and solar stills are reviewed. Subsequently,some suggestions are made to use the nanofluids in different solar thermal systems such as photovoltaic/thermal systems,solar ponds,solar thermoelectric cells,and so on. Finally,the challenges of using nanofluids in solar energy devices are discussed.

Keywords: nanohorn-based nanofluids; radiation-enhanced evaporation; heat-transfer characteristics; thermal-conductivity; cooling system;metal nanoparticles; optical-properties; forced-convection; economic-analysis; particle-size

来源出版物:International Journal of Heat and Mass Transfer,2013,57(2): 582-594联系邮箱:Pop,I; popm.ioan@yahoo.co.uk

被引频次: 49

Entropy generation in steady MHD flow due to a rotating porous disk in a nanofluid

Rashidi,MM; Abelman,S; Mehr,NF

Abstract: We consider the analysis of the second law of thermodynamics applied to an electrically conducting incompressible nanofluid fluid flowing over a porous rotating disk in the presence of an externally applied uniform vertical magnetic field. This study has applications in rotating magneto-hydrodynamic(MHD)energy generators for new space systems and also thermal conversion mechanisms for nuclear propulsion space vehicles. Von Karman transformations are employed to transform the governing equations into a system of nonlinear ordinary differential equations. The entropy generation equation is derived as a function of velocity and temperature gradient. This equation is non-dimensionalized using geometrical and physical flow field-dependent parameters. The velocity profiles in radial,tangential and axial directions,temperature distribution,averaged entropy generation number and Bejan number are obtained. A very good agreement is observed between the obtained results of the current study and those of previously published studies. The effects of physical flow parameters such as magnetic interaction parameter,suction parameter,nanoparticle volume fraction and the type of nanofluid on all fluid velocity components,temperature distribution,averaged entropy generation number and Bejan number,skin friction coefficient and Nusselt number are examined and analyzed and the path for optimizing the entropy is also proposed. In addition,this simulation represents the feasibility of using magnetic rotating disk drives in novel nuclear space propulsion engines and this model has important applications in heat transfer enhancement in renewable energy systems and industrial thermal management.

Keywords: heat-transfer characteristics; stretching sheet; mass-transfer; convection; particles

来源出版物:International Journal of Heat and Mass Transfer,2013,62: 515-525

联系邮箱:Rashidi,MM; mm.rashidi@usherbrooke.ca

被引频次: 36

A review on empirical mode decomposition in fault diagnosis of rotating machinery

Lei,YG; Lin,J; He,ZJ; et al.

Abstract: Rotating machinery covers a broad range of mechanical equipment and plays a significant role in industrial applications. It generally operates under tough working environment and is therefore subject to faults,which could be detected and diagnosed by using signal processing techniques. Empirical mode decomposition(EMD)is one of the most powerful signal processing techniques and has been extensively studied and widely applied in fault diagnosis of rotating machinery. Numerous publications on the use of EMD for fault diagnosis have appeared in academic journals,conference proceedings and technical reports. This paper attempts to survey and summarize the recentresearch and development of EMD in fault diagnosis of rotating machinery,providing comprehensive references for researchers concerning with this topic and helping them identify further research topics. First,the EMD method is briefly introduced,the usefulness of the method is illustrated and the problems and the corresponding solutions are listed. Then,recent applications of EMD to fault diagnosis of rotating machinery are summarized in terms of the key components,such as rolling element bearings,gears and rotors. Finally,the outstanding open problems of EMD in fault diagnosis are discussed and potential future research directions are identified. It is expected that this review will serve as an introduction of EMD for those new to the concepts,as well as a summary of the current frontiers of its applications to fault diagnosis for experienced researchers.

Keywords: hilbert-huang transform; vibration signal analysis; composite wingbox structures; wigner-ville distribution; emd method; damage detection; roller-bearings; feature-extraction; wavelet transform; dynamic-response

来源出版物:Mechanical Systems and Signal Processing,2013,35(1-2): 108-126联系邮箱:Lei,YG; yaguolei@mail.xjtu.edu.cn

被引频次: 34

Magnetic field effects on natural convection flow of a nanofluid in a horizontal cylindrical annulus using Lattice Boltzmann method

Ashorynejad,HR; Mohamad,AA; Sheikholeslami,M

Abstract: Effect of static radial magnetic field on natural convection heat transfer in a horizontal cylindrical annulus enclosure filled with nanofluid is investigated numerically using the Lattice Boltzmann method(LBM). The inner and outer cylinder surfaces are maintained at the different uniform temperatures. The surfaces are non-magnetic material. The investigation is carried out for different governing parameters namely,Hartmann number,nanoparticle volume fraction and Rayleigh number. The effective thermal conductivity and viscosity of nanofluid are calculated using the Maxwell-Garnetts(MG)and Brinkman models,respectively. The results reveal that the flow oscillations can be suppressed effectively by imposing an external radial magnetic field. Also,it is found that the average Nusselt number is an increasing function of nanoparticle volume fraction and Rayleigh number,while it is a decreasing function of Hartmann number.

Keywords: heat-transfer enhancement; rectangular enclosure; simulation; cavity; walls

来源出版物:International Journal of Thermal Sciences,2013,64: 240-250联系邮箱:Mohamad,AA; h.r.ashorynejad@stu.nit.ac.ir

ENGINEERING MULTIDISCIPLINARY 工程,综合

被引频次: 73

Hierarchical multi-innovation stochastic gradient algorithm for Hammerstein nonlinear system modeling

Ding,F

Abstract: This paper decomposes a Hammerstein nonlinear system into two subsystems,one containing the parameters of the linear dynamical block and the other containing the parameters of the nonlinear static block,and presents a hierarchical multi-innovation stochastic gradient identification algorithm for Hammerstein systems based on the hierarchical identification principle. The proposed algorithm is simple in principle and easy to implement on-line. A simulation example is provided to test the effectiveness of the proposed algorithm.

Keywords: squares identification methods; errors-in-variables; dual-rate systems; parameter-estimation; armax systems; accuracy

来源出版物:Applied Mathematical Modelling,2013,37(4): 1694-1704联系邮箱:Ding,F; fding@jiangnan.edu.cn

被引频次: 55

Two-stage least squares based iterative estimation algorithm for CARARMA system modeling

Ding,F

Abstract: For stochastic systems described by the controlled autoregressive autoregressive moving average(CARARMA)models,a new-type two-stage least squares based iterative algorithm is proposed for identifying the system model parameters and the noise model parameters. The basic idea is based on the interactive estimation theory and to estimate the parameter vectors of the system model and the noise model,respectively. The simulation results indicate that the proposed algorithm is effective.

Keywords: parameter-estimation algorithm; rate stochastic-systems; moving average systems; state-space models; dual-rate systems; identification methods; performance analysis; forgetting factor; auxiliary model; miso systems

来源出版物:Applied Mathematical Modelling,2013,37(7): 4798-4808联系邮箱:Ding,F; fding@jiangnan.edu.cn

被引频次: 43

The effects of MHD and temperature dependent viscosity on the flow of non-Newtonian nanofluid in a pipe: Analytical solutions

Ellahi,R

Abstract: This article examines the magnetohydrodynamic(MHD)flow of non-Newtonian nanofluid in a pipe. The temperature of the pipe is assumed to be higher than the temperature of the fluid. In particular two temperature dependent viscosity models,have been considered.The nonlinear partial differential equations along with the boundary conditions are first cast into a dimensionless form and then the equations are solved by homotopy analysis method(HAM). Explicit analytical expressions for the velocity field,the temperature distribution and nano concentration have been derived analytically. The effects of various physical parameters on velocity,temperature and nano concentration are discussed by using graphical approach.

Keywords: homotopy analysis method; 3rd grade fluid; differential-equations

来源出版物:Applied Mathematical Modelling,2013,37(3): 1451-1467联系邮箱:Ellahi,R; rellahi@engr.ucr.edu

被引频次: 43

Optical gas sensing: a review

Hodgkinson,J; Tatam,RP

Abstract: The detection and measurement of gas concentrations using the characteristic optical absorption of the gas species is important for both understanding and monitoring a variety of phenomena from industrial processes to environmental change. This study reviews the field,covering several individual gas detection techniques including non-dispersive infrared,spectrophotometry,tunable diode laser spectroscopy and photoacoustic spectroscopy. We present the basis for each technique,recent developments in methods and performance limitations. The technology available to support this field,in terms of key components such as light sources and gas cells,has advanced rapidly in recent years and we discuss these new developments. Finally,we present a performance comparison of different techniques,taking data reported over the preceding decade,and draw conclusions from this benchmarking.

Keywords: cavity-enhanced absorption; tunable diode-laser; quantum-cascade laser; ring-down spectroscopy; light-emitting-diodes; difference-frequency-generation; photonic-crystal fibers; wavelength modulation spectroscopy; fourier-transform spectroscopy; in-situ measurements

来源出版物:Measurement Science & Technology,2013,24(1): 012004联系邮箱:Hodgkinson,J; j.hodgkinson@cranfield.ac.uk

被引频次: 40

Combined state and least squares parameter estimation algorithms for dynamic systems

Ding,F

Abstract: The control theory and automation technology cast the glory of our era. Highly integrated computer chip and automation products are changing our lives. Mathematical models and parameter estimation are basic for automatic control. This paper discusses the parameter estimation algorithm of establishing the mathematical models for dynamic systems and presents an estimated states based recursive least squares algorithm,and the states of the system are computed through the Kalman filter using the estimated parameters. A numerical example is provided to confirm the effectiveness of the proposed algorithm.

Keywords: moving average systems; box-jenkins systems; identification methods; performance analysis; iterative estimation; model

来源出版物:Applied Mathematical Modelling,2014,38(1): 403-412联系邮箱:Ding,F; fding@jiangnan.edu.cn

ENGINEERING OCEAN 海洋工程

被引频次: 12

Depth-induced wave breaking in a non-hydrostatic,near-shore wave model

Smit,P; Zijlema,M; Stelling,G

Abstract: The energy dissipation in the surf-zone due to wave breaking is inherently accounted for in shock-capturing non-hydrostatic wave models,but this requires high vertical resolutions. To allow coarse vertical resolutions a hydrostatic front approximation is suggested. It assumes a hydrostatic pressure distribution at the front of a breaking wave which ensures that the wave front develops a vertical face. Based on the analogy between a hydraulic jump and a turbulent bore,energy dissipation is accounted for by ensuring conservation of mass and momentum. Results are compared with observations of random,uni-directional waves in wave flumes,and to observations of short-crested waves in a wave basin. These demonstrate that the resulting model can resolve the relevant near-shore wave processes in a short-crested wave-field,including wave breaking and wave-driven horizontal circulations.

Keywords: boussinesq-type equations; free-surface flows; shallow-water; propagation; nearshore; zone; form

来源出版物:Coastal Engineering,2013,76: 1-16联系邮箱:Smit,P; p.b.smit@tudelft.nl

被引频次: 12

Perturbation of dispersive shallow water waves

Razborova,P; Triki,H; Biswas,A

Abstract: This paper addresses the dynamics of dispersive shallow water wave that is governed by the Rosenau-KdV equation with power law nonlinearity. The singular 1-soliton solution is derived by the ansatz method. Subsequently,the soliton perturbation theory is applied to obtain the adiabatic parameter dynamics of the water waves. Finally,the integration of the perturbed Rosenau-KdV equation is obtained bythe ansatz method as well as the semi-inverse variational principle.

Keywords: power-law nonlinearity; solitary waves; rosenau-kdv; solitons; equation

来源出版物:Ocean Engineering,2013,63: 1-7联系邮箱:Biswas,A; biswas.anjan@gmail.com

被引频次: 12

Removing Spurious Low-Frequency Variability in Drifter Velocities

Lumpkin,R; Grodsky,SA; Centurioni,L; et al.

Abstract: Satellite-tracked drifting buoys of the Global Drifter Program have drogues,centered at 15-m depth,to minimize direct wind forcing and Stokes drift. Drogue presence has historically been determined from submergence or tether strain records. However,recent studies have revealed that a significant fraction of drifters believed to be drogued have actually lost their drogues,a problem that peaked in the mid-2000 s before the majority of drifters in the global array switched from submergence to tether strain sensors. In this study,a methodology is applied to the data to automatically reanalyze drogue presence based on anomalous downwind ageostrophic motion. Results indicate that the downwind slip of undrogued drifters is approximately 50% higher than previously believed. The reanalyzed results no longer exhibit the dramatic and spurious interannual variations seen in the original data. These results,along with information from submergence/tether strain and transmission frequency variations,are now being used to conduct a systematic manual reevaluation of drogue presence for each drifter in the post-1992 dataset.

Keywords: undrogued drifters; tropical pacific; wind; altimeter; currents

来源出版物:Journal of Atmospheric and Oceanic Technology,2013,30(2): 353-360联系邮箱:Lumpkin,R; rick.lumpkin@noaa.gov

被引频次: 12

Simulating coastal engineering processes with OpenFOAM(R)

Higuera,P; Lara,JL; Losada,IJ

Abstract: In the present work,the OpenFOAM(R)newly developed wave generation and active absorption boundary condition presented in the companion paper(Higuera et al.,submitted for publication)is validated. In order to do so the simulation of some of the most interesting physical processes in coastal engineering is carried out and comparisons with relevant experimental benchmark cases presented. Water waves are found to be generated realistically and agreement between laboratory and numerical data is very high regarding wave breaking,run up and undertow currents.

Keywords: 3-dimensional interaction; wave generation; circular island; long waves; breaking; runup; models

来源出版物:Coastal Engineering,2013,71: 119-134联系邮箱:Losada,IJ; losadai@unican.es

被引频次: 11

Modification and Tests of Particle Probe Tips to Mitigate Effects of Ice Shattering

Korolev,A; Emery,E; Creelman,K

Abstract: Ice particle shattering may significantly contaminate measurements taken by airborne particle probes in ice clouds. Environment Canada and the NASA Glenn Research Center(GRC)undertook efforts to modify and test probe tips in order to mitigate the effect of shattering on measurements. This work presents an overview of the results obtained during the design work on the particle probe arm tips. Even though this work was focused on the modifications of three of the probes-Particle Measuring Systems Inc.(PMS)Forward Scattering Spectrometer Probe and optical array probe,and Droplet Measurement Technologies(DMT)Cloud Imaging Probe-the outcomes of this work bear a general character and are applicable to other similar instruments. The results of the airflow analysis around the probe's housing and the simulations of particle bouncing from the probe tips are discussed here. The originally designed and modified tips were tested in a high-speed wind tunnel in ice and liquid sprays. The ice particle bouncing processes as well as patterns of water shedding over the surface of the probes arms were studied with the help of a high-speed video camera. It was found that at aircraft speed,after bouncing from a solid surface,ice particles may travel several centimeters across the airflow and bounce forward up to 1 cm. For the first time it has been directly documented with high-speed video recording that the sample volumes of particle probes with the originally designed tips are contaminated by shattered and bounced particles. A set of recommendations on the existing modification and the design of future particle probe housings is presented.

Keywords: optical array probes; crystals; breakup; fssp; size

来源出版物:Journal of Atmospheric and Oceanic Technology,2013,30(4): 690-708联系邮箱:Korolev,A; alexei.korolev@ec.gc.ca

(责任编辑姚玉琴)

Stochastic Synchronization of Markovian Jump Neural Networks With Time-Varying Delay Using Sampled Data

Wu,ZG; Shi,P; Su,HY; et al.

In this paper,the problem of sampled-data synchronization for Markovian jump neural networks with time-varying delay and variable samplings is considered. In the framework of the input delay approach and the linear matrix inequality technique,two delay-dependent criteria are derived to ensure the stochastic stability of the error systems,and thus,the master systems stochastically synchronize with the slave systems. The desired mode-independent controller is designed,which depends upon the maximum sampling interval. The effectiveness and potential of the obtained results is verified by two simulation examples.

exponential stability analysis; distributed delays; discrete; parameters; systems; stabilization

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