2006年2月3日 美国《科学》周刊311卷 第5761期津巴布韦和全球抗击艾滋病毒
一个国际小组的新研究报告指出，从1998年到2003年，津巴布韦东部的HIV人群感染率平均下降了23%到20.5%。Simon Gregson和同事说，这是第一个在南部非洲发现HIV人群感染率下降的研究。根据这些研究人员的调查，感染率降低也许部分是因为男女之间推迟了性行为的开始，以及有性经验的男女与随意伙伴性交的行为减少。在年青的受过教育的人群中，HIV感染率下降得最多，在17到29岁的男性中感染率下降了23%，在15到24岁的女性中感染率下降了49%。在一篇相关的研究评述中，Richard Hayes和Helen Weiss写道，虽然这条来自津巴布韦的消息很好，但是撒哈拉沙漠以南的非洲国家仍然是HIV全球流行的重灾区，HIV的预防工作仍然是这个地区公共卫生问题的重点。
另一篇报告指出，加强中、低收入国家中的预防工作能在今后10年中在世界范围内避免3000万个新的HIV感染者。John Stover和同事说，在这些国家中进行针对性传播和注射传播的预防项目大约需要1220亿美元，但这能实质性地节省治疗费用。他们的计算结果显示，在防止新感染上每花费3900美元，就能在治疗和护理上节省出4700美元。文章作者给出结论："我们的分析提议，低中收入国家的政府和捐款国家最好尽快加大预防项目的力度"。
报告：HIV Decline Associated with Behavior Change in Eastern Zimbabwe, Simon Gregson, et al.
科学特快报告：The Global Impact of Scaling-Up HIV/AIDS Prevention Programs in Low- and Middle-Income Countries, John Stover, et al.
研究评述：Understanding HIV Epidemic Trends in Africa, Richard Hayes and Helen Weiss
监测鱼群及其行为
为了演示一种新的遥感技术，科学家用该技术跟踪了美国纽约长岛东南水域中几公里中的一群上千万条鱼的位置和行为。文章作者说，与此相比，现有的鱼类调查方法只能采样大洋中狭窄的水域，从而只能提供海洋鱼类种群丰富程度和行为的不完整和不明确的纪录。研究人员跟踪的大社会鱼群中的主要成员大概是大西洋鲱鱼、铜盆鱼、鳕鱼、或黑海鲈，他们说这个鱼群也许是自然界中被即时观测到的最大动物群体。这个技术的关键是从船上发出圆柱形的低频率声波，然后接收由鱼或地质结构反射回来的波加以分析。文章第一作者Nicholas Makris说，分析反射波方法的改进使研究人员能够即时监测的区域比过去可能的增加了100万倍，他把这个新的鱼遥感技术比作将大洋当成一个二维的光纤或是一个"声学波导"。
报告：Fish Population and Behavior Revealed by Instantaneous Continental Shelf-Scale Imaging, Nicholas C. Makris, et al.
大鼠的嗅觉是立体的
大鼠在一个立体处理系统的帮助下能快速地找到香蕉油和其它气味的来源，这个系统能响应气味强度和气味到每个鼻孔所用时间的不同，类似与对声音的立体处理。Raghav Rajan和同事发现，大鼠大脑的嗅球中，90%的神经元对来自左边或右边的气味的响应不同。这些研究人员训练大鼠在其周围快速一闻后，去舔右边或左边的水管子来指示味道是从哪边的管子出来的。这些大鼠通常只需要闻一下，用50毫秒的时间处理信息后，就能确定出气味的方向。Rajan和同事说，对大鼠来说，"每一闻是对其嗅觉环境的一个知觉完全的快照，包括了气味的强度和立体位置"。
报告：Rats Smell in Stereo, Raghav Rajan, James P. Clement, and Upinder S. Bhalla
聚合物膜净化氢气
一组研究人员研制出新的能在高压下净化氢气流的聚合物膜，这种膜在把滤下的杂质结合到其结构中后变得更有选择性、对氢气的渗透性变得更好。工业应用中的氢气需要经过净化，但是净化过程的费用颇高，主要是因为现有的膜净化技术需要在净化后重新给气体施加压力。Haiqing Lin 和同事研制的聚合物膜由高分枝聚氧化乙烯组成，在吸收二氧化碳、硫化氢、和其它杂质后塑料化。研究人员说，塑料化改进了膜捕捉杂质的能力，使纯氢气能更好地通过。
报告：Plasticization-Enhanced Hydrogen Purification Using Polymeric Membranes, Haiqing Lin, Elizabeth Van Wagner, Benny D. Freeman, Lora G. Toy, and Raghubir P. Gupta
酶结构可能帮助治疗癌症
在癌细胞生长中起作用的一个特定酶的晶体结构的发现也许能帮助研究人员研制肿瘤抑制剂。Qing Huai和同事报告了尿激酶纤溶酶原激活因子(urokinase plasminogen activator 简称uPA)的晶体结构，这个酶对消除血栓很重要，而且该酶与它的一个细胞受体影响肿瘤的生长和转移。uPA 是首先从人尿中分离出来的，它在受多种癌症影响的组织中有明显地增加，是一个识别恶性肿瘤的标志物。研究人员发现，凹形的uPA受体表现出一些细胞灵活性，这也许能使它与多种分子相互作用，为设计可能对停止肿瘤生长有用的新酶提供了一个基础。
报告：Structure of Human Urokinase Plasminogen Activator in Complex with Its Receptor, Qing Huai, et al.
评估人工制造的纳米材料的安全性
本期一篇综述的作者考虑了纳米材料重要的化学和生物性质，概述了评估这些材料安全性的必要性。作者说，纳米材料的独特性质提供了多种技术应用的前景，但是我们需要检测这些性质对人类的生物效应。根据某些估计，纳米技术具有2015年在美国成为1万亿美元规模工业的前景。 Andre Nel和同事说，虽然科学幻想小说作家想象出的、比如世界被“灰胶(grey goo)”或成群的纳米机器人(nanobots)接管的情景发生的可能性极小，但是这些人工制造的纳米材料对人类和环境的生物效应仍大多未知。这些材料已经在商业上有应用，比如在半导体、化妆品、以及微电子学中，未来它们会在诊断、成像、和给药等方面有更多的医学应用。
综述：Toxic Potential of Materials at the Nanolevel, Andre Nel, Tian Xia, Lutz Madler, and Ning Li
This Week in Science
Editor summaries of this week's papers.
Science 3 February 2006: 573.
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Editorial:
Advancing the Frontiers
Alan I. Leshner
Science 3 February 2006: 577.
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Editors' Choice
Highlights of the recent literature.
Science 3 February 2006: 579.
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NetWatch
Best of the Web in science.
Science 3 February 2006: 585.
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Gordon Research Conferences
Science 3 February 2006: 676-699.
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NEW PRODUCTS
Science 3 February 2006: 675.
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News of the Week
SCIENCE EDUCATION: Strategies Evolve as Candidates Prepare for Kansas Board Races
Yudhijit Bhattacharjee
Science 3 February 2006: 588-589.
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PLANETARY SCIENCE: New Hubble Image Cuts the "10th Planet" Down to Size
Robert Irion
Science 3 February 2006: 589.
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EVOLUTION: Hidden Genetic Variation Yields Caterpillar of a Different Color
Elizabeth Pennisi
Science 3 February 2006: 591.
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INFECTIOUS DISEASES: Tackling Neglected Diseases Could Offer More Bang for the Buck
Gretchen Vogel
Science 3 February 2006: 592-593.
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GLOBAL WARMING: Climate Change Demands Action, Says U.K. Report
Daniel Clery
Science 3 February 2006: 592.
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BIOMEDICAL RESEARCH POLICY: NIH Lends a Hand to Postdocs Seeking to Become Independent Researchers
Jocelyn Kaiser
Science 3 February 2006: 593.
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THEORETICAL PHYSICS: Ring Around a Quasar May Deflate Quantum Foam After All
Adrian Cho
Science 3 February 2006: 594.
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U.S. INNOVATION: Bandwagon Builds for Energy Research
Eli Kintisch
Science 3 February 2006: 594-595.
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SCIENTIFIC CONDUCT: Panel Discredits Findings of Tokyo University Team
Dennis Normile
Science 3 February 2006: 595.
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ScienceScope
Science 3 February 2006: 591.
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Random Samples
Science 3 February 2006: 587.
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Newsmakers
Science 3 February 2006: 605.
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News Focus
NEUROSCIENCE: A Timely Debate About the Brain
Yudhijit Bhattacharjee
Science 3 February 2006: 596-598.
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ARATA KOCHI PROFILE: Fighting Words From WHO's New Malaria Chief
John Bohannon
Science 3 February 2006: 599.
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BIOMEDICAL ENGINEERING: Spending Itself Out of Existence, Whitaker Brings a Field to Life
David Grimm
Science 3 February 2006: 600-601.
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AMERICAN ASTRONOMICAL SOCIETY MEETING: Laser Points to Bright New Era for Ground-Based Astronomy
Robert Irion
Science 3 February 2006: 602-603.
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AMERICAN ASTRONOMICAL SOCIETY MEETING: Pulsar Sets a Dizzying Standard
Robert Irion
Science 3 February 2006: 602.
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AMERICAN ASTRONOMICAL SOCIETY MEETING: Pesky Companions Warp the Milky Way
Robert Irion
Science 3 February 2006: 603.
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AMERICAN ASTRONOMICAL SOCIETY MEETING: Snapshots From the Meeting
Robert Irion
Science 3 February 2006: 603.
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Letters
This Week's Letters
Science 3 February 2006: 606.
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Reactions to the Hwang Scandal
Sang Chul Park;, Stuart H. Orkin;, T. John Martin;, and L. Stephen Kwok
Science 3 February 2006: 606-607.
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Questions About Forensic Science
Rockne Harmon, Bruce Budowle;, Glenn Langenburg;, Max M. Houck;, Jan Seaman Kelly;, Michael J. Saks, and Jonathan J. Koehler
Science 3 February 2006: 607-610.
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Corrections and Clarifications
Science 3 February 2006: 610.
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Books et al.
SCIENCE AND RELIGION: A Compassionate Universe?
Esther Sternberg
Science 3 February 2006: 611-612.
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SCIENCE AND LITERATURE: Reading with Selection in Mind
Harold Fromm
Science 3 February 2006: 612-613.
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Browsings
Science 3 February 2006: 613.
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Books Received
Science 3 February 2006: 613.
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Policy Forum
RESEARCH CONDUCT: Lessons of the Stem Cell Scandal
Mildred K. Cho, Glenn McGee, and David Magnus
Science 3 February 2006: 614-615.
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PUBLIC HEALTH: Community Studies for Vaccinating Schoolchildren Against Influenza
M. Elizabeth Halloran and Ira M. Longini Jr.
Science 3 February 2006: 615-616.
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Perspectives
NEUROSCIENCE: What's in a Face?
Nancy Kanwisher
Science 3 February 2006: 617-618.
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ASTRONOMY: Big Fields on Small Stars
Gibor Basri
Science 3 February 2006: 618-619.
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CHEMISTRY: Better Asymmetric Reactions
Martin Wills
Science 3 February 2006: 619-620.
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EPIDEMIOLOGY: Enhanced: Understanding HIV Epidemic Trends in Africa
Richard Hayes and Helen Weiss
Science 3 February 2006: 620-621.
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Review
Toxic Potential of Materials at the Nanolevel
Andre Nel, Tian Xia, Lutz Mädler, and Ning Li
Science 3 February 2006: 622-627.
Abstract »| Full Text »| PDF »|
Brevia
Effective Seed Dispersal Across a Fragmented Landscape
Cecile F. E. Bacles, Andrew J. Lowe, and Richard A. Ennos
Science 3 February 2006: 628.
Dispersal of seeds, rather than pollen, maintains gene flow among forest remnants for a wind-pollinated, wind-dispersed tree in the Scottish Southern Uplands.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Research Article
New Neurons Follow the Flow of Cerebrospinal Fluid in the Adult Brain
Kazunobu Sawamoto, Hynek Wichterle, Oscar Gonzalez-Perez, Jeremy A. Cholfin, Masayuki Yamada, Nathalie Spassky, Noel S. Murcia, Jose Manuel Garcia-Verdugo, Oscar Marin, John L. R. Rubenstein, Marc Tessier-Lavigne, Hideyuki Okano, and Arturo Alvarez-Buylla
Science 3 February 2006: 629-632.
Published online 12 January 2006 [DOI: 10.1126/science.1119133] (in Science Express Research Articles)
Fluid flow set up by the coordinated beating of cilia along the brain's ventricles carries signaling factors that guide neurons migrating through the underlying tissue.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Reports
The Large-Scale Axisymmetric Magnetic Topology of a Very-Low-Mass Fully Convective Star
Jean-François Donati, Thierry Forveille, Andrew Collier Cameron, John R. Barnes, Xavier Delfosse, Moira M. Jardine, and Jeff A. Valenti
Science 3 February 2006: 633-635.
Tomographic imaging with polarized light from a low-mass star reveals that its magnetic field is strong and dipolar despite vigorous convection.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Optical Signatures of Coupled Quantum Dots
E. A. Stinaff, M. Scheibner, A. S. Bracker, I. V. Ponomarev, V. L. Korenev, M. E. Ware, M. F. Doty, T. L. Reinecke, and D. Gammon
Science 3 February 2006: 636-639.
Published online 12 January 2006 [DOI: 10.1126/science.1121189] (in Science Express Reports)
A combination of electric field resonances and optical excitation can couple a pair of neutral and charged quantum dots, which can then exchange quantum-stored information.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Plasticization-Enhanced Hydrogen Purification Using Polymeric Membranes
Haiqing Lin, Elizabeth Van Wagner, Benny D. Freeman, Lora G. Toy, and Raghubir P. Gupta
Science 3 February 2006: 639-642.
Highly branched, cross-linked polymer membranes can effectively remove carbon dioxide and hydrogen sulfide during hydrogen purification, even at high pressures.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Asymmetric Hydrogenation of Unfunctionalized, Purely Alkyl-Substituted Olefins
Sharon Bell, Bettina Wüstenberg, Stefan Kaiser, Frederik Menges, Thomas Netscher, and Andreas Pfaltz
Science 3 February 2006: 642-644.
Published online 8 December 2005 [DOI: 10.1126/science.1121977] (in Science Express Reports)
An iridium catalyst accomplishes the longstanding goal of adding hydrogen across alkyl-substituted carbon double bonds to generate homochiral products, a common reaction in organic synthesis.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Plastic Deformation of MgGeO3 Post-Perovskite at Lower Mantle Pressures
Sébastien Merkel, Atsushi Kubo, Lowell Miyagi, Sergio Speziale, Thomas S. Duffy, Ho-kwang Mao, and Hans-Rudolf Wenk
Science 3 February 2006: 644-646.
Experiments on an analog of a major mineral in Earth's deepest mantle imply that alignment of mineral grains by flow could explain observed seismic signals.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Natural and Experimental Evidence of Melt Lubrication of Faults During Earthquakes
Giulio Di Toro, Takehiro Hirose, Stefan Nielsen, Giorgio Pennacchioni, and Toshihiko Shimamoto
Science 3 February 2006: 647-649.
Experiments and analysis on natural faults show that melt produced by friction during faulting weakens the fault, allowing sliding at lower stresses.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Evolution of a Polyphenism by Genetic Accommodation
Yuichiro Suzuki and H. Frederik Nijhout
Science 3 February 2006: 650-652.
Laboratory selection for tobacco hornworms that change color when warm produces a polyphenism, in which one genome yields alternative phenotypes in different environments.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Resolving the Motional Modes That Code for RNA Adaptation
Qi Zhang, Xiaoyan Sun, Eric D. Watt, and Hashim M. Al-Hashimi
Science 3 February 2006: 653-656.
Motions of local and larger domain regions in a regulatory RNA allow it to take on different conformations, enabling it to bind to diverse targets.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Structure of Human Urokinase Plasminogen Activator in Complex with Its Receptor
Qing Huai, Andrew P. Mazar, Alice Kuo, Graham C. Parry, David E. Shaw, Jennifer Callahan, Yongdong Li, Cai Yuan, Chuanbing Bian, Liqing Chen, Bruce Furie, Barbara C. Furie, Douglas B. Cines, and Mingdong Huang
Science 3 February 2006: 656-659.
The structure of a receptor-ligand complex implicated in tumor growth and metastasis may provide a basis for the design of anticancer drugs.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Fish Population and Behavior Revealed by Instantaneous Continental Shelf-Scale Imaging
Nicholas C. Makris, Purnima Ratilal, Deanelle T. Symonds, Srinivasan Jagannathan, Sunwoong Lee, and Redwood W. Nero
Science 3 February 2006: 660-663.
A remote-sensing method can detect shoals of fish that are thousands of square kilometers in size, revealing their migration habits and group behavior.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
HIV Decline Associated with Behavior Change in Eastern Zimbabwe
Simon Gregson, Geoffrey P. Garnett, Constance A. Nyamukapa, Timothy B. Hallett, James J. C. Lewis, Peter R. Mason, Stephen K. Chandiwana, and Roy M. Anderson
Science 3 February 2006: 664-666.
A decrease in HIV infections in Zimbabwe may reflect a larger trend across sub-Saharan Africa resulting from national programs, condom use, and fear of AIDS.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Rats Smell in Stereo
Raghav Rajan, James P. Clement, and Upinder S. Bhalla
Science 3 February 2006: 666-670.
Like vision and audition in humans, olfaction in rats is a stereo sense, in which relative timing and intensity of the stimulus in each nostril helps to locate the source of odors.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
A Cortical Region Consisting Entirely of Face-Selective Cells
Doris Y. Tsao, Winrich A. Freiwald, Roger B. H. Tootell, and Margaret S. Livingstone
Science 3 February 2006: 670-674.
All of the neurons within a discrete part of the cortex of the macaque monkey are activated exclusively by faces.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Technical Comments
Comment on "Neutral Ecological Theory Reveals Isolation and Rapid Speciation in a Biodiversity Hot Spot"
Rampal S. Etienne, Andrew M. Latimer, John A. Silander, Jr., and Richard M. Cowling
Science 3 February 2006: 610.
Abstract »| Full Text »| PDF »|
