“分子”《科学》（20231013出版）一周论文导读

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编译 | 冯维维

Science, Volume 382, Issue 6667, October 2023

《科学》第382卷，6667期，2023年10月

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化学Chemistry

Atomic faulting induced exceptional cryogenic strain hardening in gradient cell–structured alloy

原子断裂诱发梯度胞状结构合金异常低温应变硬化

▲ 作者：QINGSONG PAN, MUXIN YANG, RUI FENG, ANDREW CHIHPIN CHUAN, KE AN, PETER K. LIAW, XIAOLEI WU, NAIRONG TAO, AND LEI LU

▲ 链接：https://www.science.org/doi/full/10.1126/science.adj3974

▲ 摘要：

粗晶材料表现出最高的应变硬化和最佳的拉伸延展性，被广泛接受。研究者通过实验报道，在77开尔文的变形阶段，具有梯度位错细胞的稳定单相合金的应变硬化率甚至超过了粗晶合金。

与传统的理解相反，这种特殊的应变硬化源于一种独特的动态结构细化机制，这种机制是由大量多向微小堆积断层(平面缺陷)的发射和运动促进的，这与传统的线性位错介导的变形从根本上不同。

原子尺度的平面变形断裂在塑性变形中的主导地位为金属材料的强化和硬化提供了一种不同的方法，提供了有前途的性能和潜在的应用。

▲ Abstract

Coarse-grained materials are widely accepted to display the highest strain hardening and the best tensile ductility. We experimentally report an attractive strain hardening rate throughout the deformation stage at 77 kelvin in a stable single-phase alloy with gradient dislocation cells that even surpasses its coarse-grained counterparts. Contrary to conventional understanding, the exceptional strain hardening arises from a distinctive dynamic structural refinement mechanism facilitated by the emission and motion of massive multiorientational tiny stacking faults (planar defects), which are fundamentally distinct from the traditional linear dislocation–mediated deformation. The dominance of atomic-scale planar deformation faulting in plastic deformation introduces a different approach for strengthening and hardening metallic materials, offering promising properties and potential applications.

Exploiting the Marcus inverted region for first-row transition metal–based photoredox catalysis

利用过渡金属基光氧化还原催化

▲ 作者：AMY Y. CHAN, ATANU GHOSH, JONATHAN T. YARRANTON, JACK TWILTON, JIAN JIN, DANIELA M. ARIAS-ROTONDO, HOLT A. SAKAI, JAMES K. MCCUSKER, AND DAVID W. C. MACMILLAN

▲ 链接：https://www.science.org/doi/full/10.1126/science.adj0612

▲ 摘要：

钌和铱配合物是有利的可调光氧化还原催化剂，但这些贵金属的费用是其使用的一个缺点。更轻、更丰富的金属被认为是不合适的，因为它们预期会从光激发态迅速弛豫。

研究者报告称，钴配合物与传统的联吡啶配体表现出令人惊讶的长激发态寿命，他们将其归因于马库斯倒转区域行为。

地球上丰富的金属在芳基酰胺与芳基硼酸的光氧化还原偶联中是有效的，并且更普遍地为这类催化剂的更大可持续性打开了大门。

▲ Abstract

Ruthenium and iridium complexes are advantageously tunable photoredox catalysts, but the expense of these precious metals is a drawback to their use. Lighter, more abundant metals have been considered unsuitable because of their anticipated rapid relaxation from photoexcited states. Chan et al. report that a cobalt complex with conventional bipyridyl ligands manifests a surprisingly long excited state lifetime, which they attribute to Marcus inverted region behavior (see the Perspective by Yaltseva and Wenger). The Earth-abundant metal is effective at photoredox coupling of aryl amides with aryl boronic acids and more generally opens the door to greater sustainability in this catalyst class. 

Direct observation of chirality-induced spin selectivity in electron donor–acceptor molecules

电子供体-受体分子中手性诱导自旋选择性的直接观察

▲ 作者：HANNAH J. ECKVAHL, NIKOLAI A. TCYRULNIKOV, ALESSANDRO CHIESA, JILLIAN M. BRADLEY, RYAN M. YOUNG, STEFANO CARRETTA, MATTHEW D. KRZYANIAK, AND MICHAEL R. WASIELEWSKI

▲ 链接：https://www.science.org/doi/full/10.1126/science.adj5328

▲ 摘要：

手性诱导的自旋选择性自发现以来，在过去的二十年里进行了深入的研究。从本质上讲，这种现象表现为手性分子的电子自旋极化，尽管迄今为止的观察仅限于吸附在固体基质上的样品。

研究者报道了在自由浮动的分子中，通过手性桥，供体和受体片段之间的分子内电子转移过程中显著的手性诱导自旋选择性特征。这些系统的精确可调性和可追溯性应该能够与不断发展的理论模型进行系统比较。

▲ Abstract

Chirality-induced spin selectivity has undergone intensive study in the two decades since its discovery. Essentially, the phenomenon manifests as polarization of electron spin by chiral molecules, although the observations thus far have pertained to samples adsorbed on a solid substrate. Eckvahl et al. report significant chirality-induced spin selectivity signatures during intramolecular electron transfer between donor and acceptor fragments across a chiral bridge in free-floating molecules . The precise tunability and tractability of these systems should enable systematic comparisons with evolving theoretical models. 

Ice-confined synthesis of highly ionized 3D-quasilayered polyamide nanofiltration membranes

高电离三维准层聚酰胺纳滤膜的冰约束合成

▲ 作者：YANQIU ZHANG, HAO WANG, JING GUO, XIQUAN CHENG, GANG HAN, CHER HON LAU, HAIQING LIN, SHAOMIN LIU, JUN MA, AND LU SHAO

▲ 链接：https://www.science.org/doi/full/10.1126/science.adi9531

▲ 摘要：

现有的聚酰胺(PA)膜合成方案以控制扩散为主的液相反应为基础，这些反应会产生低于标准的空间结构和电离行为。

研究者报道了一种冰约束界面聚合策略，可有效控制界面反应的动力学控制和含单体的六方多型(Ih)冰相的热力学操纵，从而合理地合成用于纳滤的三维准层状PA膜。

实验和分子模拟证实了潜在的膜形成机制。该冰限PA纳滤膜具有高密度的电离结构和特殊的传输通道，实现了优异的透水性和优异的离子选择性。

▲ Abstract

Existing polyamide (PA) membrane synthesis protocols are underpinned by controlling diffusion-dominant liquid-phase reactions that yield subpar spatial architectures and ionization behavior. We report an ice-confined interfacial polymerization strategy to enable the effective kinetic control of the interfacial reaction and thermodynamic manipulation of the hexagonal polytype (Ih) ice phase containing monomers to rationally synthesize a three-dimensional quasilayered PA membrane for nanofiltration. Experiments and molecular simulations confirmed the underlying membrane formation mechanism. Our ice-confined PA nanofiltration membrane features high-density ionized structure and exceptional transport channels, realizing superior water permeance and excellent ion selectivity.

生态学Ecology

Boom-bust cycles in gray whales associated with dynamic and changing Arctic conditions

灰鲸的盛衰周期与北极条件的动态变化有关

▲ 作者：JOSHUA D. STEWART, TREVOR W. JOYCE, JOHN W. DURBAN, DEBORAH FAUQUIER, HOLLY FEARNBACH9, JACQUELINE M. GREBMEIER, MORGAN LYNN, MANFREDI MANIZZA, etc.

▲ 链接：https://www.science.org/doi/full/10.1126/science.adi1847

▲ 摘要：

气候变化正在影响广泛的全球系统，其中极地生态系统的变化最为迅速。尽管气候影响最直接地影响低营养水平和短命物种，但尚不清楚长寿和流动物种将如何应对快速的极地变暖，因为它们可能在适应新条件的同时具有适应生态破坏的短期能力。

研究发现，一个标志性的、高度移动的极地相关物种的种群动态与北极猎物的可用性和进入觅食区域的途径密切相关。

当低猎物生物量与高冰盖同时发生时，灰鲸经历了重大的死亡事件，每次都会使种群减少15%到25%。这表明，随着北极变暖，即使是移动的、长寿的物种也对动态和不断变化的环境很敏感。

▲ Abstract

Climate change is affecting a wide range of global systems, with polar ecosystems experiencing the most rapid change. Although climate impacts affect lower-trophic-level and short-lived species most directly, it is less clear how long-lived and mobile species will respond to rapid polar warming because they may have the short-term ability to accommodate ecological disruptions while adapting to new conditions. We found that the population dynamics of an iconic and highly mobile polar-associated species are tightly coupled to Arctic prey availability and access to feeding areas. When low prey biomass coincided with high ice cover, gray whales experienced major mortality events, each reducing the population by 15 to 25%. This suggests that even mobile, long-lived species are sensitive to dynamic and changing conditions as the Arctic warms.

生命科学Life Science

Direct observation of glycans bonded to proteins and lipids at the single-molecule level

在单分子水平上直接观察与蛋白质和脂质结合的聚糖

▲ 作者：KELVIN ANGGARA, LAURA SR?AN, THAPAKORN JAROENTOMEECHAI, XU WU, STEPHAN RAUSCHENBACH, YOSHIKI NARIMATSU, HENRIK CLAUSEN, THOMAS ZIEGLER, REBECCA L. MILLER, AND KLAUS KERN

▲ 链接：https://www.science.org/doi/full/10.1126/science.adh3856

▲ 摘要：

许多蛋白质，特别是那些由真核细胞分泌的蛋白质，有糖链附着，以促进质量控制或介导蛋白质—蛋白质或细胞—细胞相互作用。

这些糖通常是复杂和异质的，用传统的结构或生物物理方法来研究是具有挑战性的。研究表明，可以使用单分子原子力显微镜直接对附着在肽和脂质的聚糖进行成像。

这些生物分子可以通过温和的电喷雾沉积应用到表面上，如果必要的话，可以通过操纵来拉伸结构区域。作者观察到不同的聚糖结构和成像的大片段蛋白质，包括密集糖基化粘蛋白。

▲ Abstract

Many proteins, especially those that are secreted from eukaryotic cells, have sugar chains attached to facilitate quality control or mediate protein-protein or cell-cell interactions. These sugars are often complex and heterogeneous and can be challenging to study by conventional structural or biophysical methods. Anggara et al. show that glycans attached to peptides and lipids can be imaged directly using single-molecule atomic force microscopy. These biomolecules can be applied to a surface by a gentle electrospray deposition and, if necessary, manipulated to stretch out structured regions. The authors observed distinct glycan configurations and imaged large fragments of proteins, including a densely glycosylated mucin.

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