《科学》(20181012出版）一周论文导读

Vol. 362, No. 6411，12 October 2018

2018年10月12日，第362卷6411期

生物学Biology

Pan-tumor genomic biomarkers for PD-1 checkpoint blockade–based immunotherapy

针对基于PD1检查点阻断免疫疗法的泛癌症基因生物标记

▲ 作者：Razvan Cristescu, Robin Mogg, Mark Ayers, Andrew Albright, Erin  Murphy, et al

▲ 相关链接：

http://science.sciencemag.org/content/362/6411/eaar3593

摘要：

程序性细胞死亡蛋白1（PD-1）和程序性细胞死亡配体1（PD-L1）检查点阻断免疫疗法在多种癌症中起到了持久的抗肿瘤作用，但并非所有患者都会产生反应。

我们报告了来自4项KEYNOTE临床试验的涉及22个肿瘤类型和超过300个患者样本的评估结果。

肿瘤突变负荷（TMB）和炎性T细胞基因表达谱（GEP）在辨别针对PD-1抗体派姆单抗的应答者和非应答者方面展示出联合预测效用。

Abstract

Programmed cell death protein–1 (PD-1) and programmed cell death ligand–1 (PD-L1) checkpoint blockade immunotherapy elicits durable antitumor effects in multiple cancers, yet not all patients respond. We report the evaluation of >300 patient samples across 22 tumor types from four KEYNOTE clinical trials. Tumor mutational burden (TMB) and a T cell–inflamed gene expression profile (GEP) exhibited joint predictive utility in identifying responders and nonresponders to the PD-1 antibody pembrolizumab.

Thyroid hormone signaling specifies cone subtypes in human retinal organoids

甲状腺激素信号指定人类视网膜类器官中锥体亚型

▲ 作者：Kiara C. Eldred, Sarah E. Hadyniak, Katarzyna A. Hussey, Boris Brenerman, et al

▲ 相关链接：

http://science.sciencemag.org/content/362/6411/eaau6348

摘要：

指定人类神经系统内神经元亚型的潜在机制基本鲜为人知。视网膜的蓝色（S）、绿色（M）和红色（L）锥体使高敏锐度的白天和色彩视觉成为可能。

为确定控制S和L/M命运的机制，我们研究了人类视网膜类器官的区别。

类器官和视网膜拥有相似的分布、表达谱和锥体亚型结构。S锥体首先被指定出来，然后是L/M锥体，而甲状腺激素信号控制了这一顺序开关。

Abstract

The mechanisms underlying specification of neuronal subtypes within the human nervous system are largely unknown. The blue (S), green (M), and red (L) cones of the retina enable high-acuity daytime and color vision. To determine the mechanism that controls S versus L/M fates, we studied the differentiation of human retinal organoids. Organoids and retinas have similar distributions, expression profiles, and morphologies of cone subtypes. S cones are specified first, followed by L/M cones, and thyroid hormone signaling controls this temporal switch. 

化学Chemistry

Confined acids catalyze asymmetric single aldolizations of acetaldehyde enolates

受限酸催化乙醛烯醇化物的非对称单羟醛缩合

▲ 作者：Lucas Schreyer, Philip S. J. Kaib, Vijay N. Wakchaure, Carla Obradors, et al

▲ 相关链接：

http://science.sciencemag.org/content/362/6411/216

摘要：

形成反应功能和某种原料化合物相同的产品的反应通常以低聚反应结束。

作为一个突出例子，仅拥有一个合作衬底的最小（尽管据称最有用）的可烯醇化醛——乙醛的选择性醇醛耦合被证实非常具有挑战性。

这里，我们报告了一种具有高度对映选择性的向山羟醛缩合反应。其产生了乙醛以及各种脂肪族和芳香族受体醛的三乙基硅烷（TES）和叔丁基二甲硅基（TBS）烯醇化物。

Abstract

Reactions that form a product with the same reactive functionality as that of one of the starting compounds frequently end in oligomerization. As a salient example, selective aldol coupling of the smallest, though arguably most useful, enolizable aldehyde, acetaldehyde, with just one partner substrate has proven to be extremely challenging. Here, we report a highly enantioselective Mukaiyama aldol reaction with the simple triethylsily (TES) and tert-butyldimethylsilyl (TBS) enolates of acetaldehyde and various aliphatic and aromatic acceptor aldehydes.

Entropy-driven stability of chiral single-walled carbon nanotubes

手性单壁碳纳米管熵驱动的稳定性

▲ 作者：Yann Magnin, Hakim Amara, François Ducastelle, Annick Loiseau, et al

▲ 相关链接：

http://science.sciencemag.org/content/362/6411/212

摘要：

单壁碳纳米管是可通过碳掺杂在与催化剂形成的界面上生长到几厘米长的空心圆柱体。它们展示出半导体或者金属性质，而这取决于其生长期间被确定的螺旋性。

为支撑针对选择性合成的探索，我们开发了一种将纳米管—催化剂界面能量、温度和由此产生的纳米管手性关联起来的热力学模型。

我们证实，碳纳米管能发展出手性是因为其纳米级边缘的结构熵，并由此解释了实验观察到的手性分布的温度变化。

Abstract

Single-walled carbon nanotubes are hollow cylinders that can grow centimeters long via carbon incorporation at the interface with a catalyst. They display semiconducting or metallic characteristics, depending on their helicity, which is determined during their growth. To support the quest for a selective synthesis, we develop a thermodynamic model that relates the tube-catalyst interfacial energies, temperature, and the resulting tube chirality. We show that nanotubes can grow chiral because of the configurational entropy of their nanometer-sized edge, thus explaining experimentally observed temperature evolutions of chiral distributions.

材料和物理学

Materials Science and Physics

Key-and-lock commodity self-healing copolymers

钥匙和锁链间连接的商业化自我修复共聚物

▲ 作者：Marek W. Urban, Dmitriy Davydovich, Ying Yang, Tugba Demir,  Yunzhi Zhang, Leah Casabianca

▲ 相关链接：

http://science.sciencemag.org/content/362/6411/220

摘要：

自我修复材料因能从物理或化学损伤中恢复而引发注意。

我们报告称，诸如聚甲基丙烯酸/丙烯酸正丁酯[p(MMA/nBA)]及其衍生物等商业化共聚物能在经受机械损伤时自我修复。

这种行为发生在针对倾向性地同随机成分相互交替的共聚物拓扑构建的狭窄成分范围内，并且被归因于形成钥匙和锁链间连接的有利的链间范德华力。

利用范德华力而非超分子或共价再结合以及封装反应物消除了化学和物理改变，并且在无须外部干预的情况下使针对机械损伤的多种修复成为可能。

Abstract

Self-healing materials are notable for their ability to recover from physical or chemical damage. We report that commodity copolymers, such as poly(methyl methacrylate)/n-butyl acrylate [p(MMA/nBA)] and their derivatives, can self-heal upon mechanical damage. This behavior occurs in a narrow compositional range for copolymer topologies that are preferentially alternating with a random component (alternating/random) and is attributed to favorable interchain van der Waals forces forming key-and-lock interchain junctions. The use of van der Waals forces instead of supramolecular or covalent rebonding or encapsulated reactants eliminates chemical and physical alterations and enables multiple recovery upon mechanical damage without external intervention.

Electrical generation and detection of spin waves in a quantum Hall ferromagnet

量子霍尔铁磁体中自旋波的电产生和探测

▲ 作者：Di S. Wei, Toeno van der Sar, Seung Hwan Lee, Kenji Watanabe,  Takashi Taniguchi, Bertrand I. Halperin, Amir Yacoby

▲ 相关链接：

http://science.sciencemag.org/content/362/6411/229

摘要：

自旋波是磁性系统的集体激发。

研究长寿命自旋波物理学的一个吸引人的装置是在处于低温和垂直磁场下的清洁二维电子系统中自发形成的量子霍尔（QH）铁磁体。

我们利用QH边缘通道在石墨烯中失去平衡的占据，激发并探测到磁有序QH状态的自旋波。

我们的试验提供了关于N = 0朗道能级下通过不同铁磁相以及绝缘管式反铁磁相的长距离自旋波传播的直接证据。

Abstract

Spin waves are collective excitations of magnetic systems. An attractive setting for studying long-lived spin-wave physics is the quantum Hall (QH) ferromagnet, which forms spontaneously in clean two-dimensional electron systems at low temperature and in a perpendicular magnetic field. We used out-of-equilibrium occupation of QH edge channels in graphene to excite and detect spin waves in magnetically ordered QH states. Our experiments provide direct evidence for long-distance spin-wave propagation through different ferromagnetic phases in the N = 0 Landau level, as well as across the insulating canted antiferromagnetic phase. 

其他/天文学Others/Astronomy

A hot and fast ultra-stripped supernova that likely formed a compact neutron star binary

可能形成致密中子星双星系统的炎热和快速超剥离型超新星

▲ 作者：K. De, M. M. Kasliwal, E. O. Ofek, T. J. Moriya, J. Burke, Y.  Cao, S. B. Cenko, et al

▲ 相关链接：

http://science.sciencemag.org/content/362/6411/201

摘要：

致密中子星双星系统由两颗大质量恒星通过涉及两颗超新星爆炸的恒星演化形成。形成这些系统的最后阶段尚未被直接观测到。

我们报告了iPTF 14gqr（SN 2014ft）的发现。这是一颗Ic型超新星，拥有表明极低喷出物质量（约等于0.2个太阳质量）和低动能（约等于2 ×10⁵⁰尔格）的快速演化的光变曲线。

早期光度测定和光谱学揭示了一个扩展的富含氦的信封状天体的骤冷证据。其可能在前身星爆炸前失去质量的激烈阶段被喷射出来。

Abstract

Compact neutron star binary systems are produced from binary massive stars through stellar evolution involving up to two supernova explosions. The final stages in the formation of these systems have not been directly observed. We report the discovery of iPTF 14gqr (SN 2014ft), a type Ic supernova with a fast-evolving light curve indicating an extremely low ejecta mass (≈0.2 solar masses) and low kinetic energy (≈2 × 10⁵⁰ ergs). Early photometry and spectroscopy reveal evidence of shock cooling of an extended helium-rich envelope, likely ejected in an intense pre-explosion mass-loss episode of the progenitor.

考古学Archaeology

Response to Comment on “U-Th dating of carbonate crusts reveals Neandertal origin of Iberian cave art”

对“碳酸盐外壳铀—钍年龄揭示伊比利亚洞穴艺术尼安德特起源”评论的回应

▲ 作者：D. L. Hoffmann, C. D. Standish, M. García-Diez, P. B. Pettitt, J. A. Milton, J. Zilhão, J. J. Alcolea-González, et al

▲ 相关链接：

http://science.sciencemag.org/content/362/6411/eaau1736

摘要：

Slimak等人对我们关于同西班牙洞穴壁画存在关联的碳酸盐的最古老（超过6.5万年）铀—钍年龄的可靠性提出了挑战。

他们援引的证据是这一时期之后的2.5万年里缺少岩石和洞穴艺术以及同开放系统行为相关的潜在方法学问题和对碎屑或者水源水²³⁰钍的修正。

我们证明他们的批评是没有根据的。

Abstract

Slimak et al. challenge the reliability of our oldest (>65,000 years) U-Th dates on carbonates associated with cave paintings in Spain. They cite a supposed lack of parietal art for the 25,000 years following this date, along with potential methodological issues relating to open-system behavior and corrections to detrital or source water ²³⁰Th. We show that their criticisms are unfounded.

（宗华）

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