国际科技信息

国际科技信息

美国约翰·霍普金斯儿童中心、密西西比大学医学中心和麻省大学医学院的研究人员3月3日在第20届逆转录病毒和机会性感染大会上报告说，他们首次实现了对一名感染艾滋病病毒（HIV）婴儿的“功能性治愈”。这项成果将有助于为根治儿童艾滋病病毒感染铺平道路。

“功能性治愈”艾滋病婴儿

据物理学家组织网报道，这名婴儿的母亲是位艾滋病病毒感染者，在他出生30小时后，医生便对其实施了抗逆转录病毒联合治疗。一系列测试表明，婴儿血液中的病毒在逐步减少，在他出生29天之后，病毒降低到了无法检测的水平。治疗一直持续到该婴儿18个月大时停止。10个月后，多次对其进行标准的血液检测，均没有发现血液中存在艾滋病病毒。HIV特异性抗体这

美国首次“功能性治愈”艾滋病婴儿

一标准的HIV感染临床指标的测试结果也始终为负。

研究人员说，这名婴儿现在被视为“功能性治愈”，也就是说，无需终身用药，其体内的HIV感染已被完全控制，且标准的临床测试无法检测到血液中的HIV复制。但“功能性治愈”患者体内仍有少量病毒，可通过超灵敏方法识别出来，而与之相对而言的“根本性治愈”，则是指患者体内病毒已完全清除。

研究人员认为，可能是由于及时采用了抗病毒治疗，制止了病毒宿主的形成，该婴儿才得以治愈。病毒宿主指的是一种休眠细胞，其在大多数艾滋病患者停止治疗后短短数周内会再度引发感染，极难对付。

及早治疗是关键

目前，为防止高风险新生儿感染HIV病毒，通常会对其施以为时6周的预防性剂量的多种抗病毒药物联合治疗；而一旦确诊感染，则改用治疗性剂量。但研究人员说，此次的特殊病例可能会改变目前的做法，因为它凸显了在极早期采用抗逆转录病毒疗法的治疗潜力。

“立即对新生儿采取抗病毒疗法，防止病毒的藏身之地在第一时间形成，由此可以帮助婴儿清除病毒，实现（对感染的）长期控制，而无需终身接受治疗。” 该报告的主要作者、约翰·霍普金斯儿童中心的病毒学家德博拉·佩尔绍德说。

专家表示，不需要治疗、具有天然抑制艾滋病病毒的能力是极为罕见的，只在不到0.5%的成人艾滋病毒感染者身上观察到，他们被称为“精英控制者”，其免疫系统能抑制病毒的复制，使病毒数量保持在临床检测不到的水平。HIV专家一直在寻求一种方法，希望将所有的艾滋病患者转化为“精英控制者”，而这项最新成果有望改变局面。

“大规模地完全根除病毒是我们的长期目标，但就目前而言，这仍是遥不可及的，而对高风险新生儿实施积极、及时、准确、有针对性的抗病毒疗法，可能是我们实现功能性治愈的最佳机会。”麻省大学医学院免疫学家凯瑟琳·卢苏里亚加说。

研究人员同时提醒，他们还缺乏足够的数据，尚不能建议改变目前的做法，用治疗性剂量取代预防性剂量对高风险新生儿实施治疗，不过，这名“功能性治愈”婴儿的例子为开展原理验证研究提供了理论基础。佩尔绍德说：“下一步是要证实，这究竟是对极早期抗逆转录病毒治疗的一个极不寻常的反应，还是一种同样可适用于其他高风险新生儿的方法。”

First 'Functional Cure' of HIV in Baby?

A baby born two-and-ahalf years ago in Mississippi with HIV is the first case of a so-called"functional cure" of the infection,researchers announced recently.

Standard tests can no longer detect any traces of the AIDS-causing virus even though the child has discontinued HIV medication.

"We believe this is the first well-documented case of a [functional] cure," said study lead author Dr. Deborah Persaud,associate professor of pediatrics in the division of infectious diseases at Johns Hopkins Children's Center in Baltimore. The finding was presented Sunday at the Conference on Retroviruses and Opportunistic Infections, in Atlanta.

The child was not part of a study but, instead, the beneficiary of an unexpected and partly unplanned sequence of events that-- once confirmed and replicated in a formal study -- might help more children who are born with HIV or who at risk of contracting HIV from their mother eradicate the virus from their body.

Normally, mothers infected with HIV take antiretroviral drugs that can almost eliminate the odds of the virus being transferred to the baby.

If a mother doesn't know her HIV status or hasn't been treated for other reasons, the baby is given"prophylactic" drugs at birth while awaiting the results of tests to determine his or her HIV status.This can take four to six weeks to complete. If the tests are positive,the baby starts HIV drug treatment.

The mother of the baby born in Mississippi didn't know she was HIV-positive until the time of delivery.

But in this case, both the initial and confirmatory tests on the baby were able to be completed within one day, allowing the baby to be started on HIV drug treatment within the first 30 hours of life.

"Most of our kids don't get picked up that early," Persaud explained.

As expected, the baby's "viral load" -- detectable levels of HIV --decreased progressively until it was no longer detectable at 29 days of age.

Theoretically, this child(doctors aren't disclosing the gender) would have taken the medications for the rest of his or her life, said the researchers,who included doctors from the University of Massachusetts Medical School and the University of Mississippi Medical Center.

Instead, the child stayed on the regimen for only 18 months before dropping out of the medical system and discontinuing the drugs.

Ten months after stopping treatment, however, the child was again seen by doctors who were surprised to find no HIV virus or HIV antibodies with standard tests.

Ultrasensitive tests did detect infinitesimal traces of viral DNA and RNA in the blood. But the virus was not replicating -- a highly unusual occurrence given that drugs were no longer being administered, the researchers said.

德国企业创立了有机太阳能电池效率世界新高

有机薄膜太阳能技术全球领先的德国Heliatek公司，近日公布其有机太阳能电池效率又创世界新高，达到了12%，由此打破了该公司于9个月前创立的10.7%的记录。新效率已得到了专业检测机构的认证。

实现新纪录的电池为1.1cm2标准尺寸，含有两种享有专利的吸收材料，它们可将不同波段中的光转换成电。

通过两种吸收体的组合，可以借助更高的光电压提高对光子的吸收，更好地利用能源。由于有机光伏在高温下的独到性能与低辐射，12%的效率可与常规晶硅模块及薄膜光伏14～15%的电池效率相媲美。检测结果证实，相比于传统的太阳能技术，有机光伏的效率在弱光与高温时超越平均水平。

这项成果显示出Heliatek公司的发展战略，即聚焦于低聚吸收材料的真空沉积，而非印刷聚合物。

前者在过去的10年中已经成功地用于OLED-显示器。真空沉积可允许超薄的同质层沉降，最薄的仅有5nm厚。利用极易把握的超薄层沉积过程，可将一定数量的层叠在一起，生产有极宽的光谱吸收能力的叠层电池，甚至三结太阳能电池。

这项有机太阳能效率新纪录是Heliatek公司科研团队与德国德累斯顿及乌尔姆大学联合开发的成果，该研发计划得到了德国联邦教研部、欧盟、德国研究联合会等部门与机构的资助。基于这个成果，Heliatek公司计划至2015年将转换效率提高至15%。

该公司基于小分子（低聚物）的有机太阳能电池技术目前已处于商业生产转化之中，第一条生产线已于2012年春落成，主要生产太阳能薄膜，提供给建材、汽车等行业的合作伙伴，供他们将半成品用作产能组件，扩展自身产品的功能。

预计集成了Heliatek公司有机太阳能薄膜的产品将于2013年年底进入市场。公司计划继续投资，建成更大规模的生产线，实现批量生产，以便大幅度降低生产成本。

Heliatek achieves 12% organic solar cell efficiency

Organic solar films developer Heliatek, Dresden, Germany,reports that it has pushed the conversion efficiency of its organic photovoltaic (OPV) cells to 12%, which the company says is equivalent to at least 15% in conventional semiconductor-based cells.

The company says this performance, which was achieved in cooperation with the University of Ulm and TU Dresden, is a “world record achievement”, as measured by the accredited testing facility SGS.

SGS also validated Heliatek’s superior low light and high temperature performances of its OPV technology compared to traditional solar technologies.

The 12.0% record is based on a standard sized cell of 1.1 cm², which uses a combination of two patented absorber materials that convert light of different wavelengths. Using two different absorber materials creates a stronger absorption of photons and improves energetic utilization through a higher photovoltage.

Heliatek says that thanks to OPV’s unique behavior at high temperatures and low light conditions – when its performance either improves or remains stable– the 12% efficiency figure is equivalent to about 14% to 15%efficiency of traditional solar technologies such as crystalline silicon and thin film PV.

However, while those other technologies tend to significantly lose cell efficiency with rising temperatures and decreasing solar irradiation, organic cells increase their efficiency in these conditions leading to a much higher energy harvesting in real-world environments.

Boosting ef fi ciency

Thibaud Le Séguillon, CEO of Heliatek, commented, “We are planning to reach 15% efficiency by 2015 and gradually transfer our record efficiencies into Heliatek’s roll-to-roll production line. We manufacture solar films and not solar panels.

"Our customers in the building and construction material industry, in automotive and in light structures, such as shading and street furniture, are integrating these solar films as energy harvesting components to increase the functionality of their products.”

Martin Pfeiffer, co-founder and CTO of Heliatek, added:“Achieving 12% OPV efficiency is a clear validation of Heliatek’s choice not to focus on printed polymers but to go with vacuum deposited oligomers. This technology has been used successfully for OLED displays over the last decade.

"Vacuum deposition enables extremely thin yet homogeneous layers down to a thickness of 5nm.With this well-controlled, ultra-thin film process we can deposit a large number of layers on top of each other creating tandem, or even triple junction cells, to absorb a broader spectrum of light.”

Heliatek’s latest record efficiency for OPV improves on its previous record of 10.7%, set nine months previously. To achieve the latest leap in cell efficiency, Heliatek worked with a combination of its in-house R&D know-how, as well as its strong ties with the OPV specialist universities.

One of the two key absorbers was developed and synthesized by Ulm University’s Institute of Organic Chemistry & Advanced Materials, headed by Peter Bäuerle, co-founder of Heliatek.The cooperation also involved Karl Leo (co-founder of Heliatek) and Moritz Riede of the Institut für Angewandte Photophysik of TU Dresden.

新算法让监控复杂系统变简单

在一个复杂系统中，如包含了2万个互相联系的基因的人类基因组，要想一次监控整个系统几乎是不可能的。据物理学家组织网近日报道，来自美国东北大学、麻省理工大学等单位的研究人员开发出一种新算法，能识别出复杂系统的子单位或必要结点，使监控大型复杂系统成为可能。相关论文发表在最近出版的美国《国家科学院学报》上。

复杂系统如生物基因组、生化反应系统、社会网络等，由许多互相关联的子部分组成，其中任何一个部分有了变化，都会对其余部分造成影响。因此要分析监控一个复杂系统是极为困难的。“复杂系统的本质是连接，各组成部分之间要凭借这些连接，才能将信息分布到整个网络。因此我们不必监控每个部分，也能从整体上把握整个系统。”论文作者之一、东北大学生物学院和计算机与信息科学院物理学教授艾伯特-拉斯洛·巴拉巴斯说，他们设计的方法利用了复杂系统子单位间相互依赖的特性，可超越数量限制观察系统的整体情况。

利用这种新算法，研究小组首次确定了用以描述系统动态学的所有数学方程，比如计算在一个生化反应系统中，外围分子之间较小的反应对整个系统最终结果所产生的影响。通过观察每个反应对系统变量所造成的影响，就能绘制出整个系统的曲线图。连结点是构成曲线图的基础，每个点对理解系统其他部分而言都是不可缺少的。

“令我们吃惊的是，在绝大部分例子中，必要结点也是充分条件。”东北大学复杂网络研究中心副教授刘阳煜（音译）说，只要有了这些必要结点，无需其他任何部分就能知道整个系统的全部情况。

研究人员指出，新方法将控制论、图论和网络科学结合在一起，将大型复杂系统简化为一套必要的“传感结点”。比如生物的新陈代谢系统，是由上百分子和上千生化反应组成的集合，新算法能使识别其中生物标记的过程大大简化。生物标记是血液中的分子，能帮医生辨别一个人是否健康。“目前的大部分生物标记几乎都是随机选择的，只是化学家和医生发现它们管用而已。”巴拉巴斯说，“而我们的方法是可观察的，为选择生物标记提供了一条理性的途径，只要我们知道所要监控的是什么系统。”

Through a sensor, clearly: Complex systems made observable

A complex system can, in principle, be observable – that is,the system's complete internal state can be reconstructed from its outputs, which would ostensibly involve describing in complete quantitative detail all of its internal state variables at once. In an actual experiment, however, such measurement is typically beyond our reach, and so is limited to a smaller number of those variables.Referred to as sensors (or sensor nodes), these key variables can be used to make the complete system observable. Recently, scientists at Northeastern University and MIT devised a graphical approach that first derives the math e mat ical equa tions describing a complex system's dynamics, and then determines the key sensors for that system. Moreover, when applying their approach to biochemical reaction systems, the researchers discovered that the derived sensors were both necessary and sufficient to describe the complete system. The scientists conclude that their findings allow a systematic exploration of many diverse natural, technological and socioeconomic systems.

Dr. Yang-Yu Liu comments on the research he, Prof. Albert-László Barabási and Prof. Jean-Jacques Slotine performed, starting with the three main challenges they faced. "The primary challenge is that for many nonlinear systems,we don't know the system parameters," Liu tells Phys.org."However, conceptually it is quite straightforward to adopt a graphical approach derived from the dynamical laws that govern a system to determine the sensors that are necessary to reconstruct the full internal state of a complex system."

In fact, control theorists have been working on the concept of system digraphs some time. Liu and his associates used this approach to study the observability problem for highly nonlinear systems, which he says that to his knowledge has not been previously addressed."The surprise," Liu adds, "was that,except for some pathological cases which almost never occur in real systems, the sensors we identified are not only necessary but also sufficient: Usually, we expect that to observe the system we'd need to monitor more sensors than just the necessary nodes, since if the topology of a dynamic system's inference diagram is very complex,it's hard to have any symmetries.However, the complicated topology somehow helped us achieve system observability." An inference diagram reveals the underlying structure of information flow or casualty when the measurements are performed.

新催化剂让氢气的运输和释放变轻松

德国罗斯托克大学化学工程师开发出一种新催化剂，能从液体甲醇中轻松提取氢气，让氢气存储和运输变得更加容易。研究人员认为，这种方法消除了“氢经济”中的最大障碍，将来有望把氢气“装入”甲醇通过管道、油罐车运输存储，用时再通过化学反应将氢气提取出来，为边远农村发电或为汽车等交通工具提供燃料。

氢气燃烧值很高，清洁无污染，但缺点是无法大量收集，很难存储，运输也不安全。如将其压缩液化，不仅方法很复杂而且要耗费大量能量。几十年来，许多化学家一直在寻找吸收存储氢气的最佳方法，让氢气成为便捷可靠的燃料。

目前方法之一是用固体或液体材料来吸收“封存”氢气，虽然候选材料很多，但要么“装”得太少，要么结合得太紧，再次释放很不容易。甲醇能把氢气直接转化为液体燃料，利用催化剂可把氢气和一氧化碳结合成甲醇，同时甲醇也能吸收大量氢气，约为本身重量的12.5%。但甲醇也存在释放氢气的问题，要让它释放氢气，以往的方法要把甲醇加热到200摄氏度，并施加25到50个大气压。

罗斯托克大学化学工程师马赛厄斯·贝尔和同事开发出一种可溶解的钌基催化剂，能在65到95摄氏度和常压下，有效地从存储甲醇中释放出氢气。“这节约的能量是难以估计的。”贝尔说，把甲醇变成一种切实可行的“装氢箱”的目的基本达到，将来有望给手机、计算机、汽车燃料电池供电。

英国牛津大学化学家埃德曼·唐也一直在研究氢气存储，他将新方法称为一个“重要发现”，尤其是反应不需要高温，和氢燃料电池运行所产生的废热大致相同，这意味着能把甲醇—氢气反应和氢电电池结合起来，这是很有吸引力的。虽然还有些障碍，但这种甲醇—氢气转化法是值得尝试的，因为直接用甲醇提供动力的话，氢燃料电池的效率是一般燃料电池的两倍。

贝尔还指出，该工艺目前还处于初期阶段，实现商业化还要再等几年。技术方面还存在一些障碍，尤其是针对大规模反应。

比如用来驱动汽车的话，要求反应每秒产生24升氢气，而实验室反应每分钟只产生几毫升氢气；催化剂也必须很稳定，能存放数月或数年之久，目前能达到至少3周；此外，反应中产生的二氧化碳也要被吸收以减少碳排放。

Liquid storage could make hydrogen a feasible fuel

A process for extracting hydrogen from a liquid fuel could remove one of the biggest hurdles to a 'hydrogen economy', its discoverers say.

They have developed a catalyst that harvests the gas from methanol, a liquid fuel that —unlike hydrogen itself — can be easily transported and stored.

Matthias Beller, a chemical engineer at the University of Rostock in Germany, and his colleagues hope that methanol might one day be sluiced through pipelines and poured into tankers,before chemical reactions convert the liquid back to hydrogen where it is needed — for example to provide power to off-grid villages,or run cars or mobile devices.

Hydrogen has a high energy density and is completely clean,burning to leave behind only water vapour as waste.

It cannot be mined in large amounts, but proponents of a hydrogen economy say that it could be produced in vast quantities from water using excess electricity from wind turbines and solar plants.

Unfortunately, because hydrogen is a gas it is difficult to store and transport safely unless compressed or liquefied, which is cumbersome and takes a lot of energy. Many chemists have spent decades studying how best to trap hydrogen for use as a fuel.

Liquid storage

Locking the gas up in the form of solid or liquid chemicals is one answer. Many materials proposed for hydrogen storage, however,either don’t trap much, or hold onto the hydrogen so tightly that it takes an unfeasible amount of energy to retrieve.

That was the problem with methanol.

It is straightforward to turn hydrogen into the liquid fuel: a well-known reaction combines hydrogen and carbon monoxide gases using commercial catalysts.Methanol also traps a lot of hydrogen (12.5% by weight).

Yet to release the gas,chemists have previously had to heat liquid methanol to 200 °C at 25–50 times atmospheric pressure.

But Beller and his colleagues report today in Nature1 that they have discovered a soluble ruthenium-based catalyst that can efficiently turn methanol into hydrogen at a mere 65–95 °C, and at ambient pressure.

"It is difficult to estimate how much energy will be saved," says Beller.

The process is still at an early stage, years away from commercialization. But he thinks that it could be enough to make methanol a viable energy carrier,potentially delivering hydrogen for fuel cells in mobile phones,computers or even cars.

Edman Tsang, a chemist at the University of Oxford, UK, who also works on storing hydrogen in liquids including methanol2,says that the work is a "major discovery". In particular, he says,the low temperature of the reaction is attractive because it is about the same temperature as the waste heat from an operating hydrogen fuel cell. That means that it may be possible to combine a methanol–hydrogen reaction with a fuel cell that guzzles up the gas to produce electricity.

Technical hurdles

There are technical hurdles to overcome, however — not least of which is scaling up the reaction.To produce enough power to run a car, for example, the reaction would have to yield some 24 litres of hydrogen a second; in the lab,Beller has demonstrated only millilitres of flow per minute.

The catalyst would also need to be stable for months or years,whereas Beller has so far shown only that it is stable for at least three weeks.

美国科学家利用转基因工程让植物叶子含油脂

美国密歇根州立大学研究人员26日表示，他们通过转基因工程获得了叶子含油脂的植物。此举有望促进生物燃料的生产以及改善动物饲料的营养。

在传统的生物燃料研究中，因植物种子能自然产生油脂，叶和茎等组织不会存储油脂，人们关注的重点是如何提高植物种子的油脂含量，几乎没有人研究利用植物叶和茎生产生物燃料的问题。

在新研究中，研究人员利用藻类涉及产生油脂的基因使得其他植物在其叶子中存储油脂或植物油。

这对多数植物而言，在自然状况下是十分罕见的现象。

相关的研究成果刊登在新出版的《植物细胞》杂志上。

密歇根州立大学生物化学和分子生物教授克里斯多夫·本宁是研究项目的负责人，研究小组的成员来自密歇根州立大学和大湖生物能源研究中心。

本宁说，不少研究人员都在试图提高植物的能量密度，新研究成果其实是实现相同目标的不同途径。

作为被验证了的概念，它有望用于促进植物内生产生物燃料的油脂的产量，同时提高动物饲料的营养水平。

在研究过程中，本宁和同事首先选取了单细胞绿藻的5个基因，并从中找到一个在置入拟南芥植物后成功地提高其叶子组织中油脂量的基因。

随后，他们将转基因拟南芥喂给毛虫幼虫食用，发现食用转基因拟南芥幼虫的体重比食用普通拟南芥幼虫的要大，从而确认转基因植物的确含有更高的营养成分和更多的能量。

对于下阶段的研究，本宁和同事们将努力提高那些具有经济价值的草和藻的油脂产量。本宁认为这是值得追逐的目标，如果从植物的叶、茎和种子中都能提取油脂，那么植物潜在的能量将翻倍。

此外，本宁表示，藻类能够在贫瘠的农地上生长，在粮食与燃油争夺土地的辩论中，会成为重要的变数。如果藻类能够通过基因工程不断地生产丰富的油脂，那么它们将替代传统的农业作物。

大湖生物燃料研究中心主任、密歇根州立大学生物化学和分子生物杰出教授肯尼斯

克艾格斯特认为，该研究成果代表着产油植物转基因工程的重要进展，将帮助人们在提高传统和非传统作物产量、质量和利润的开发方面撰写新篇章。

Fat Worms Play Role in Algal Biofuels

Fat worms confirm are playing a role in improved biofuel and animal feed production.

Researchers from Michigan State University (MSU) have successfully engineered a plant with oily leaves, a feat that could improve biofuel production.

The research was led by Christoph Benning, MSU professor of biochemistry and molecular biology along with a team from the Great Lakes Bioenergy Research Center.

The results of the study were published in the journal, The Plant Cell, and show that researchers could us an algae gene involved in oil production to engineer a plant that stores lipids or vegetable oil in it leaves. This is uncommon for most plants.

To date, little research has been done to examine the oil production of leaves and stems because in nature, most plants don’t store lipids in these tissues.

“Many researchers are trying to enhance plants’ energy density, and this is another way of approaching it,” Benning said. “It’s a proof-of-concept that could be used to boost plants’ oil production for biofuel use as well as improve the nutrition levels of animal feed.”

Benning and his colleagues began by identifying five genes from one-celled green algae.

From the five, they identified one that, when inserted into Arabidopsis thaliana, successfully boosted oil levels in the plant’s leaf tissue.

Next, to confirm that the improved plants were more nutritious and contained more energy, the research team fed them to caterpillar larvae, who gained more weight than worms that ate regular leaves.

The research team is now focusing on the enhancing oil production in grasses and algae that have economic value.

Benning says the benefits of the research make it worth pursuing.

“If oil can be extracted from leaves, stems and seeds, the potential energy capacity of plants may double,” he said. “Further,if algae can be engineered to continuously produce high levels of oil, rather than only when they are under stress, they can become a viable alternative to traditional agricultural crops.”

Moreover, algae can be grown on poor agricultural land – a big plus in the food vs. fuel debate,he added.

Ultimately the team believes they are helping to write a new chapter in the development and production of quantity, quality and profitability of traditional and nontraditional crops for use for feed and fuel.

纳米粒子递送药物技术有新进展

人体免疫系统能识别并摧毁外来物。除了细菌、病毒，递送药物的纳米粒子、植入的起搏器和人工关节等也是外来物，同样会引发免疫反应，导致药物失效、排斥或发炎。据物理学家组织网2月21日报道，美国宾夕法尼亚大学科学家开发出一种新方法，给这些治疗设备贴上蛋白质“通行证”，让它们能顺利通过人体的防御系统。相关论文发表在最近的《科学》杂志上。

“身体对入侵的外来物会一视同仁地加以排斥。”论文第一作者、宾夕法尼亚大学分子与细胞生物物理学实验室研究生派尔·罗德里格斯说，这是由身体天然免疫系统所引发的。这一过程涉及多种细胞，如巨噬细胞能发现、吞掉并破坏入侵者；血清蛋白会黏在目标物上，引起巨噬细胞注意，一旦巨噬细胞确定黏住的是外来物就会吞掉它，或发信号召集其他巨噬细胞一起来包围它。为避免纳米粒子引发天然免疫反应，早期的办法是给它们涂一层高分子的“刷子外衣”，这些“刷子”从纳米粒子中伸出来，阻止各种血清蛋白黏在它表面。但这只能暂缓一时而不能最终解决问题。宾夕法尼亚大学工程与应用科学学院化学与生物分子工程教授丹尼斯 迪斯科和研究小组另辟蹊径：让巨噬细胞相信纳米粒子是“自己人”而放过它们。

早在2008年，迪斯科小组发现人体细胞膜上有一种叫做CD47的蛋白，它能与巨噬细胞受体SIRPa结合。就像巡警检查人们的通行证，CD47蛋白会告诉巨噬细胞是“自己人，别吃我”。随后有其他研究人员破解了CD47和SIRPa的连接结构。

利用这些信息，迪斯科小组绘制出了执行类似CD47蛋白功能所需的最小氨基酸序列，并将这种“小肽”折叠起来作为固体“通行证”。他们用化学方法合成了这种小肽，将其黏附在抗癌药物递送粒子上，然后注射到小鼠体内检验其功效。这些小鼠经过基因改造，其巨噬细胞具有和人类相同的SIRPa受体。

研究人员给小鼠注射了两种纳米粒子：一种携带小肽通行证，另一种没有，然后检测小鼠免疫系统要多久能识别出来。“我们每10分钟抽一次血，检测两种纳米粒子各剩下多少。”罗德里格斯说，“最初注射两种粒子的比例是1∶1，20分钟到30分钟后，有小肽的粒子数是没有小肽的4倍。”“这证明小肽确实抑制了巨噬细胞的反应。我们引起它们之间的互动，然后又克服了它。”迪斯科说。对治疗用的纳米粒子而言，它们只需活到发现目标，不必无限期地留在体内，即使多出半小时时间已能带来很大利益；而对起搏器之类的长久植入体内的设备来说，则需要另外的表面蛋白结合物，让它们能和免疫系统长期和平共处。

研究人员还指出，这些小肽在进入实际应用前，还需进一步研究，将其减少到只有几个氨基酸。这一步很关键，通行证分子越简单，就越容易合成。如果能在一台机器上统一制造，并能方便地修改以适应多种植入物和注射剂，就能粘黏在多种药物递送工具上，也能黏在专门抗体上瞄准癌细胞或其他疾病组织。

Protein 'passport' helps nanoparticles get past immune system

The body's immune system exists to identify and destroy foreign objects, whether they are bacteria, viruses, flecks of dirt or splinters. Unfortunately,nanoparticles designed to deliver drugs, and implanted devices like pacemakers or artificial joints, are just as foreign and subject to the same response.

Now, researchers at the University of Pennsylvania School of Engineering and Applied Science and Penn's Institute for Translational Medicine and Therapeutics have figured out a way to provide a "passport" for such therapeutic devices, enabling them to get past the body's security system.

The research was conducted by professor Dennis Discher,graduate students Pia Rodriguez,Takamasa Harada, David Christian and Richard K. Tsai and postdoctoral fellow Diego Pantano of the Molecular and Cell Biophysics Lab in Chemical and Biomolecular Engineering at Penn.

It was published in the journal Science.

"Fromyourbody's perspective," Rodriguez said, "an arrowhead a thousand years ago and a pacemaker today are treated the same—as a foreign invader.

"We'd really like things like pacemakers, sutures and drugdelivery vehicles to not cause an inflammatory response from the innate immune system."

The innate immune system attacks foreign bodies in a general way.

Unlike the learned response of the adaptive immune system,which includes the targeted antibodies that are formed after a vaccination, the innate immune system tries to destroy everything it doesn't recognize as being part of the body.

This response has many cellular components, including macrophages—literally "big eaters"—that find, engulf and destroy invaders. Proteins in blood serum work in tandem with macrophages; they adhere to objects in the blood stream and draw macrophages' attention. If the macrophage determines these proteins are stuck to a foreign invader, they will eat it or signal other macrophages to form a barrier around it.

Drug-delivery nanoparticles naturally trigger this response, so researchers' earlier attempts to circumvent it involved coating the particles with polymer "brushes."These brushes stick out from the nanoparticle and attempt to physically block various blood serum proteins from sticking to its surface.

However, these brushes only slow down the macrophagesignaling proteins, so Discher and colleagues tried a different approach: Convincing the macrophages that the nanoparticles were part of the body and shouldn't be cleared.

美国研制新型超级电池 几秒钟内完成手机充电

目前，美国科学家最新研制一种超级电池，它们被称为微型石墨烯超级电容，其充电和放电速度比普通电池快1000倍。这种超级电池是采用单原子厚度的碳层构成，能够很容易制造并整合成为器件，未来有望制造更小的手机。

研究小组称，这项技术突破能够在最短时间内对手机和汽车快速充电，同时可用于制造体积较小的器件。美国加州大学洛杉矶大学材料科学和工程系教授理查德·卡恩说：“集合电子电路的能量存储单元的设计制造存在着挑战，经常局限于整体系统的微型化。”

为了研制这种微型超级电池，研究人员使用二维石墨烯层，在第三维立体层面其厚度仅有单个原子。同时，研究小组发现使用一种标准DVD烧录技术能够很容易制造这种新型电池。

卡恩说：“制造微型超级电容的传统方法涉及到密集型光刻技术，但被证实很难制造成本低廉的器件，因此在商业应用领域受限。目前，我们基于适用于大众的光速写DVD烧录技术，可以仅用部分传统装置成本制造出石墨烯微型超级电容。使用这种技术，我们利用廉价材料仅不足30分钟在一个光盘上制造100多个微型超级电池。”

为了使超级电池更具有效性，两个分离电极的放置方式必须使其表面积最大化。这将使超级电池能够存储更多电能。之前的微型电池是多层石墨烯堆叠在一起作为电极，有点儿像三明治面包片。

在最新设计的超级电池中，研究人员使用叉合模型(类似于互相交织的手指)将电极并排放在一起。这将有助于实现两个电极表面积的最大化，尽管这同时也会减少电解液中离子需要扩散的路径。

最终这种超级电池能够存储更多的电能，更快地完成充电。研究人员表示，人们甚至可以在家中完成这种超级电池的制造。

UCLA researchers develop new technique to scale up production of graphene micro-supercapacitors

While the demand for eversmaller electronic devices has spurred the miniaturization of a variety of technologies, one area has lagged behind in this downsizing revolution: energystorage units, such as batteries and capacitors.

Now, Richard Kaner,a member of the California NanoSystems Institute at UCLA and a professor of chemistry and biochemistry, and Maher El-Kady,a graduate student in Kaner's laboratory, may have changed the game.

The UCLA researchers have developed a groundbreaking technique that uses a DVD burner to fabricate micro-scale graphenebased supercapacitors — devices that can charge and discharge a hundred to a thousand times faster than standard batteries. These micro-supercapacitors, made from a one-atom–thick layer of graphitic carbon, can be easily manufactured and readily integrated into small devices such as next-generation pacemakers.

The new cost-effective fabrication method, described in a study published this week in the journal Nature Communications, holds promise for the mass production of these supercapacitors, which have the potential to transform electronics and other fields.

"The integration of energystorage units with electronic circuits is challenging and often limits the miniaturization of the entire system," said Kaner, who is also a professor of materials science and engineering at UCLA's Henry Samueli School of Engineering and Applied Science. "This is because the necessary energy-storage components scale down poorly in size and are not well suited to the planar geometries of most integrated fabrication processes."

"Traditional methods for the fabrication of microsupercapacitors involve laborintensive lithographic techniques that have proven difficult for building cost-effective devices,thus limiting their commercial application," El-Kady said. "Instead,we used a consumer-grade LightScribe DVD burner to produce graphene micro-supercapacitors over large areas at a fraction of the cost of traditional devices. Using this technique, we have been able to produce more than 100 microsupercapacitors on a single disc in less than 30 minutes, using inexpensive materials."

The process of miniaturization often relies on flattening technology, making devices thinner and more like a geometric plane that has only two dimensions.In developing their new microsupercapacitor, Kaner and El-Kady used a two-dimensional sheet of carbon, known as graphene, which only has the thickness of a single atom in the third dimension.

Kaner and El-Kady took advantage of a new structural design during the fabrication. For any supercapacitor to be effective,two separated electrodes have to be positioned so that the available surface area between them is maximized. This allows the supercapacitor to store a greater charge. A previous design stacked the layers of graphene serving as electrodes, like the slices of bread on a sandwich. While this design was functional, however, it was not compatible with integrated circuits.

In their new design, the researchers placed the electrodes side by side using an interdigitated pattern, akin to interwoven fingers.This helped to maximize the accessible surface area available for each of the two electrodes while also reducing the path over which ions in the electrolyte would need to diffuse. As a result, the new supercapacitors have more charge capacity and rate capability than their stacked counterparts.

Interestingly, the researchers found that by placing more electrodes per unit area, they boosted the micro-supercapacitor's ability to store even more charge.

Kaner and El-Kady were able to fabricate these intricate supercapacitors using an affordable and scalable technique that they had developed earlier. They glued a layer of plastic onto the surface of a DVD and then coated the plastic with a layer of graphite oxide.