审校：半夏 谭坤 赵维杰 邓卓
Demonstration of an ac Josephson junction laser
M. C. Cassidy, A. Bruno, S. Rubbert, M. Irfan, J. Kammhuber, R. N. Schouten, A. R. Akhmerov, L. P. Kouwenhoven*
（导读 王腾） 超导电子器件在经典和量子计算中占据了重要的地位。本研究利用交流约瑟夫森效应展示了利用与多模超导腔强耦合的约瑟夫森结制备的激光器。通过简单的制备及操作，可以很容易的集成一系列的量子器件，并且在低温下可以高效的在芯片上产生相干的微波光子。
Superconducting electronic devices have reemerged as contenders for both classical and quantum computing due to their fast operation speeds, low dissipation, and long coherence times. An ultimate demonstration of coherence is lasing. We use one of the fundamental aspects of superconductivity, the ac Josephson effect, to demonstrate a laser made from a Josephson junction strongly coupled to a multimode superconducting cavity. A dc voltage bias applied across the junction provides a source of microwave photons, and the circuit’s nonlinearity allows for efficient down-conversion of higher-order Josephson frequencies to the cavity’s fundamental mode. The simple fabrication and operation allows for easy integration with a range of quantum devices, allowing for efficient on-chip generation of coherent microwave photons at low temperatures.
Clathrate colloidal crystals
Haixin Lin, Sangmin Lee, Lin Sun, Matthew Spellings, Michael Engel, Sharon C. Glotzer, Chad A. Mirkin
（导读 陆妍婷） 研究中将三角双锥体单元（长边约250纳米，短边约177纳米）在DNA外套的引导下组装成与包合物结构，并使用电镜和分子模拟等首段对其结构和组装过程进行了分析。这些结构是目前为止通过可编程分子组装方式合成的最复杂的结构。
DNA-programmable assembly has been used to deliberately synthesize hundreds of different colloidal crystals spanning dozens of symmetries, but the complexity of the achieved structures has so far been limited to small unit cells. We assembled DNA-modified triangular bipyramids (~250-nanometer long edge, 177-nanometer short edge) into clathrate architectures. Electron microscopy images revealed that at least three different structures form as large single-domain architectures or as multidomain materials. Ordered assemblies, isostructural to clathrates, were identified with the help of molecular simulations and geometric analysis. These structures are the most sophisticated architectures made via programmable assembly, and their formation can be understood based on the shape of the nanoparticle building blocks and mode of DNA functionalization.
Radical-polar crossover reactions of vinylboron ate complexes
Marvin Kischkewitz, Kazuhiro Okamoto, Christian Mück-Lichtenfeld, Armido Studer
反应步骤和原理（Kischkewitz M, et al. 2017）
（导读 韩宇） 本文报道，铃木-宫浦偶联反应中途产生的乙烯基硼酸根络合物可以发生另一种反应，碳自由基结合于烯烃基团的另一端后，电荷转移促使硼原子上的烷基或芳基迁移至α碳上。这一反应保留了化合物中有后续反应价值的硼酸酯基团，应用前景广泛。
Vinyl boronic esters are valuable substrates for Suzuki-Miyaura cross-coupling reactions. However, boron-substituted alkenes have drawn little attention as radical acceptors, and the radical chemistry of vinylboron ate complexes is underexplored. We show here that carbon radicals add efficiently to vinylboron ate complexes and that their adduct radical anions undergo radical-polar crossover: A 1,2-alkyl/aryl shift from boron to the α-carbon sp2 center provides secondary or tertiary alkyl boronic esters. In contrast to the Suzuki-Miyaura coupling, a transition metal is not required, and two carbon-carbon bonds are formed. The valuable boronic ester moiety remains in the product and can be used in follow-up chemistry, enlarging the chemical space of the method. The cascade uses commercial starting materials and provides access to perfluoroalkylated alcohols, γ-lactones, γ-hydroxy alkylnitriles, and compounds bearing quaternary carbon centers.
Emily Sarafian, Glenn A. Gaetani, Erik H. Hauri, Adam R. Sarafian
（导读 韩宇） 海洋上方地幔的含水量可不成比例的影响其固相线。本文给出含有溶解氢橄榄岩固相线的实验测定结果，H2O-欠饱和橄榄岩固相线高于之前的猜测值。用该结果协调东太平洋隆起下熔融体系的地球物理观测需将现有大洋上地幔位温的估计值上调约60°C。
Decompression of hot mantle rock upwelling beneath oceanic spreading centers causes it to exceed the melting point (solidus), producing magmas that ascend to form basaltic crust ~6 to 7 kilometers thick. The oceanic upper mantle contains ~50 to 200 micrograms per gram of water (H2O) dissolved in nominally anhydrous minerals, which—relative to its low concentration—has a disproportionate effect on the solidus that has not been quantified experimentally. Here, we present results from an experimental determination of the peridotite solidus containing known amounts of dissolved hydrogen. Our data reveal that the H2O-undersaturated peridotite solidus is hotter than previously thought. Reconciling geophysical observations of the melting regime beneath the East Pacific Rise with our experimental results requires that existing estimates for the oceanic upper mantle potential temperature be adjusted upward by about 60°C.
Precipitation drives global variation in natural selection
（导读 马欢） 本研究探索了气候变化各个方面将会如何影响自然选择进程，预测显示降水量、蒸散和北大西洋涛动会驱动对陆地动植物种群的自然选择，而温度的影响甚微。本研究表明气候变化可能在全球范围内该表演化进程。
Climate change has the potential to affect the ecology and evolution of every species on Earth. Although the ecological consequences of climate change are increasingly well documented, the effects of climate on the key evolutionary process driving adaptation—natural selection—are largely unknown. We report that aspects of precipitation and potential evapotranspiration, along with the North Atlantic Oscillation, predicted variation in selection across plant and animal populations throughout many terrestrial biomes, whereas temperature explained little variation. By showing that selection was influenced by climate variation, our results indicate that climate change may cause widespread alterations in selection regimes, potentially shifting evolutionary trajectories at a global scale.
Persistent effects of pre-Columbian plant domestication on Amazonian forest composition
C. Levis, F. R. C. Costa, F. Bongers…C. I. A. Vela, H. ter Steege
（导读 陆妍婷） 本研究对亚马逊河流域考古遗址和前哥伦布时期驯化的85种木本植物的分布和丰度的关系进行了分析，发现在整个流域中遗址及其周边区域驯化物种的相对丰度和多度都有增加。这亚马逊的现代树木群落很大程度上是由亚马逊人对植物的长期驯化所塑造的。
The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known archaeological sites in Amazonia with the distributions and abundances of 85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely than nondomesticated species to be hyperdominant. Across the basin, the relative abundance and richness of domesticated species increase in forests on and around archaeological sites. In southwestern and eastern Amazonia, distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples.
Late Pleistocene archaic human crania from Xuchang, China
Zhan-Yang Li, Xiu-Jie Wu（吴秀杰，中科院古脊椎与古人类所）, Li-Ping Zhou, Wu Liu, Xing Gao, Xiao-Mei Nian, Erik Trinkaus（华盛顿大学）
（导读 肖坤） 研究人员在河南省许昌市的灵井遗址发掘出了距今10.5万年至12.5万年的晚更新世早期古人类头骨化石。这些头骨具有东亚古人类、欧洲尼安德特人和早期现代人的混合特征，对研究晚更新世古人类的进化模式和群体交流具有重要意义。
Two early Late Pleistocene (~105,000- to 125,000-year-old) crania from Lingjing, Xuchang, China, exhibit a morphological mosaic with differences from and similarities to their western contemporaries. They share pan–Old World trends in encephalization and in supraorbital, neurocranial vault, and nuchal gracilization. They reflect eastern Eurasian ancestry in having low, sagittally flat, and inferiorly broad neurocrania. They share occipital (suprainiac and nuchal torus) and temporal labyrinthine (semicircular canal) morphology with the Neandertals. This morphological combination reflects Pleistocene human evolutionary patterns in general biology, as well as both regional continuity and interregional population dynamics.
Epigenetic regulation of antagonistic receptors confers rice blast resistance with yield balance
Yiwen Deng, Keran Zhai, Zhen Xie…Didier Tharreau, Zuhua He（何祖华，上海植生所）
（导读 郭思瑶） 作物育种旨在平衡疾病抗性与产量之间的关系。研究人员发现了水稻中编码核苷酸结合受体的基因簇Pigm，该基因簇编码的PigmR和PigmS之间的拮抗作用可使水稻具备对真菌Magnaporthe oryzae的持久抗性，同时不影响产量，这一系统的发现有利于培育优良作物变种。
Crop breeding aims to balance disease resistance with yield; however, single resistance (R) genes can lead to resistance breakdown, and R gene pyramiding may affect growth fitness. Here we report that the rice Pigm locus contains a cluster of genes encoding nucleotide-binding leucine-rich repeat (NLR) receptors that confer durable resistance to the fungus Magnaporthe oryzae without yield penalty. Among these NLR receptors, PigmR confers broad-spectrum resistance, whereas PigmS competitively attenuates PigmR homodimerization to suppress resistance. PigmS expression, and thus PigmR-mediated resistance, are subjected to tight epigenetic regulation. PigmS increases seed production to counteract the yield cost induced by PigmR. Therefore, our study reveals a mechanism balancing high disease resistance and yield through epigenetic regulation of paired antagonistic NLR receptors, providing a tool to develop elite crop varieties.
Layer-specific modulation of neocortical dendritic inhibition during active wakefulness
William Muñoz, Robin Tremblay, Daniel Levenstein, Bernardo Rudy
（导读 韩宇） 表达生长抑素（Sst）的中间神经元是特异性执行树突抑制的GABA能神经元。本研究记录了Sst中间神经元在行为小鼠的所有新皮层中的活动，发现不同脑层中的Sst中间神经元在小鼠主动觉醒过程中的反应不同，其具体反应由胆碱能信号和Vip中间神经元的抑制作用共同决定。
γ-Aminobutyric acid (GABA)ergic inputs are strategically positioned to gate synaptic integration along the dendritic arbor of pyramidal cells. However, their spatiotemporal dynamics during behavior are poorly understood. Using an optical-tagging electrophysiological approach to record and label somatostatin-expressing (Sst) interneurons (GABAergic neurons specialized for dendritic inhibition), we discovered a layer-specific modulation of their activity in behaving mice. Sst interneuron subtypes, residing in different cortical layers and innervating complementary laminar domains, exhibited opposite activity changes during transitions to active wakefulness. The relative weight of vasoactive intestinal peptide–expressing (Vip) interneuron–mediated inhibition of distinct Sst interneurons and cholinergic modulation determined their in vivo activity. These results reveal a state-dependent laminar influence of Sst interneuron–mediated inhibition, with implications for the compartmentalized regulation of dendritic signaling in the mammalian neocortex.
DNA Fountain enables a robust and efficient storage architecture
Yaniv Erlich, Dina Zielinski
DNA喷泉编码。（Erlich Y, Zielinski D. 2017）
（导读 韩宇） DNA具有存储大容量信息的潜力。本文提出一种称为DNA喷泉的存储策略，接近每个核苷酸存储信息的理论最大值。该系统用DNA存储了一个完整的计算机操作系统，可以在每克DNA中存储215PB（10^15字节）数据，并可通过测序技术实现大规模精确检索。
DNA is an attractive medium to store digital information. Here we report a storage strategy, called DNA Fountain, that is highly robust and approaches the information capacity per nucleotide. Using our approach, we stored a full computer operating system, movie, and other files with a total of 2.14 × 106 bytes in DNA oligonucleotides and perfectly retrieved the information from a sequencing coverage equivalent to a single tile of Illumina sequencing. We also tested a process that can allow 2.18 × 1015 retrievals using the original DNA sample and were able to perfectly decode the data. Finally, we explored the limit of our architecture in terms of bytes per molecule and obtained a perfect retrieval from a density of 215 petabytes per gram of DNA, orders of magnitude higher than previous reports.
Hidden dynamics in the unfolding of individual bacteriorhodopsin proteins
Hao Yu, Matthew G. W. Siewny, Devin T. Edwards, Aric W. Sanders, Thomas T. Perkins
1µs分辨率单分子力谱测定的细菌视紫红质分子。（Yu H, et al. 2017）
（导读 韩宇） 阐明复杂蛋白的折叠细节是长期挑战。本研究用1µs分辨率的单分子力谱（SMFS）在天然脂质双分子层中将单个细菌视紫红质分子去折叠，不仅检测到了许多新的中间产物，还观察到中间状态下去折叠和重折叠之间的过渡。
Protein folding occurs as a set of transitions between structural states within an energy landscape. An oversimplified view of the folding process emerges when transiently populated states are undetected because of limited instrumental resolution. Using force spectroscopy optimized for 1-microsecond resolution, we reexamined the unfolding of individual bacteriorhodopsin molecules in native lipid bilayers. The experimental data reveal the unfolding pathway in unprecedented detail. Numerous newly detected intermediates—many separated by as few as two or three amino acids—exhibited complex dynamics, including frequent refolding and state occupancies of <10 μs. Equilibrium measurements between such states enabled the folding free-energy landscape to be deduced. These results sharpen the picture of the mechanical unfolding of membrane proteins and, more broadly, enable experimental access to previously obscured protein dynamics.
Structure of a eukaryotic voltage-gated sodium channel at near-atomic resolution
Huaizong Shen, Qiang Zhou, Xiaojing Pan, Zhangqiang Li, Jianping Wu, Nieng Yan（颜宁，清华大学）
3.8 Å分辨率下的Nav通道低温电镜结构。（Shen H, et al. 2017）
（导读 韩宇） 为了解电压门控离子通道的功能与疾病机制，本研究测出3.8 Å分辨率下美洲大蠊电压门控钠离子通道（NavPaS）的低温电镜结构。非对称选择性过滤孔腔的入口被高度糖基化且由二硫键稳定的胞外环包裹。细胞质侧的保守氨基末端域在电压感受域VSDI下方，羧基末端域则与III-IV连接处相结合。
Voltage-gated sodium (Nav) channels are responsible for the initiation and propagation of action potentials. They are associated with a variety of channelopathies and are targeted by multiple pharmaceutical drugs and natural toxins. Here, we report the cryogenic electron microscopy structure of a putative Nav channel from American cockroach (designated NavPaS) at 3.8 angstrom resolution. The voltage-sensing domains (VSDs) of the four repeats exhibit distinct conformations. The entrance to the asymmetric selectivity filter vestibule is guarded by heavily glycosylated and disulfide bond–stabilized extracellular loops. On the cytoplasmic side, a conserved amino-terminal domain is placed below VSDI, and a carboxy-terminal domain binds to the III-IV linker. The structure of NavPaS establishes an important foundation for understanding function and disease mechanism of Nav and related voltage-gated calcium channels.
A nontoxic pain killer designed by modeling of pathological receptor conformations
V. Spahn, G. Del Vecchio, D. Labuz…M. Weber, C. Stein
（导读 郭思瑶） 阿片受体的无选择性激活在舒缓疼痛同时也引起了严重的中枢和肠道副作用。研究人员通过探究阿片受体与配体相互作用时的病理构象动力学过程，利用计算机模拟设计出一种新型受体激动剂，其具有较低的酸解离常数，故能选择性地激活产生疼痛的外周μ-阿片受体，而不产生呼吸抑制，成瘾等副作用。
Indiscriminate activation of opioid receptors provides pain relief but also severe central and intestinal side effects. We hypothesized that exploiting pathological (rather than physiological) conformation dynamics of opioid receptor-ligand interactions might yield ligands without adverse actions. By computer simulations at low pH, a hallmark of injured tissue, we designed an agonist that, because of its low acid dissociation constant, selectively activates peripheral μ-opioid receptors at the source of pain generation. Unlike the conventional opioid fentanyl, this agonist showed pH-sensitive binding, heterotrimeric guanine nucleotide–binding protein (G protein) subunit dissociation by fluorescence resonance energy transfer, and adenosine 3′,5′-monophosphate inhibition in vitro. It produced injury-restricted analgesia in rats with different types of inflammatory pain without exhibiting respiratory depression, sedation, constipation, or addiction potential.
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