原文地址：http://news.sciencenet.cn/htmlnews/2023/10/510272.shtm
編譯 | 馮維維
Science, Volume 382, Issue 6667, October 2023
《科學》第382卷，6667期，2023年10月
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化學Chemistry
Atomic faulting induced exceptional cryogenic strain hardening in gradient cell–structured alloy
原子斷裂誘發梯度胞狀結構合金異常低溫應變硬化
▲ 作者：QINGSONG PAN, MUXIN YANG, RUI FENG, ANDREW CHIHPIN CHUAN, KE AN, PETER K. LIAW, XIAOLEI WU, NAIRONG TAO, AND LEI LU
▲ 鏈接：https://www.science.org/doi/full/10.1126/science.adj3974
▲ 摘要：
粗晶材料表現出最高的應變硬化和最佳的拉伸延展性，被廣泛接受。研究者通過實驗報道，在77開爾文的變形階段，具有梯度位錯細胞的穩定單相合金的應變硬化率甚至超過了粗晶合金。
與傳統的理解相反，這種特殊的應變硬化源于一種獨特的動態結構細化機制，這種機制是由大量多向微小堆積斷層(平面缺陷)的發射和運動促進的，這與傳統的線性位錯介導的變形從根本上不同。
原子尺度的平面變形斷裂在塑性變形中的主導地位為金屬材料的強化和硬化提供了一種不同的方法，提供了有前途的性能和潛在的應用。
▲ 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
利用過渡金屬基光氧化還原催化
▲ 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
▲ 鏈接：https://www.science.org/doi/full/10.1126/science.adj0612
▲ 摘要：
釕和銥配合物是有利的可調光氧化還原催化劑，但這些貴金屬的費用是其使用的一個缺點。更輕、更豐富的金屬被認為是不合適的，因為它們預期會從光激發態迅速弛豫。
研究者報告稱，鈷配合物與傳統的聯吡啶配體表現出令人驚訝的長激發態壽命，他們將其歸因于馬庫斯倒轉區域行為。
地球上豐富的金屬在芳基酰胺與芳基硼酸的光氧化還原偶聯中是有效的，并且更普遍地為這類催化劑的更大可持續性打開了大門。
▲ 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
電子供體-受體分子中手性誘導自旋選擇性的直接觀察
▲ 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
▲ 鏈接：https://www.science.org/doi/full/10.1126/science.adj5328
▲ 摘要：
手性誘導的自旋選擇性自發現以來，在過去的二十年里進行了深入的研究。從本質上講，這種現象表現為手性分子的電子自旋極化，盡管迄今為止的觀察僅限于吸附在固體基質上的樣品。
研究者報道了在自由浮動的分子中，通過手性橋，供體和受體片段之間的分子內電子轉移過程中顯著的手性誘導自旋選擇性特征。這些系統的精確可調性和可追溯性應該能夠與不斷發展的理論模型進行系統比較。
▲ 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
高電離三維準層聚酰胺納濾膜的冰約束合成
▲ 作者：YANQIU ZHANG, HAO WANG, JING GUO, XIQUAN CHENG, GANG HAN, CHER HON LAU, HAIQING LIN, SHAOMIN LIU, JUN MA, AND LU SHAO
▲ 鏈接：https://www.science.org/doi/full/10.1126/science.adi9531
▲ 摘要：
現有的聚酰胺(PA)膜合成方案以控制擴散為主的液相反應為基礎，這些反應會產生低于標準的空間結構和電離行為。
研究者報道了一種冰約束界面聚合策略，可有效控制界面反應的動力學控制和含單體的六方多型(Ih)冰相的熱力學操縱，從而合理地合成用于納濾的三維準層狀PA膜。
實驗和分子模擬證實了潛在的膜形成機制。該冰限PA納濾膜具有高密度的電離結構和特殊的傳輸通道，實現了優異的透水性和優異的離子選擇性。
▲ 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.
生態學Ecology
Boom-bust cycles in gray whales associated with dynamic and changing Arctic conditions
灰鯨的盛衰周期與北極條件的動態變化有關
▲ 作者：JOSHUA D. STEWART, TREVOR W. JOYCE, JOHN W. DURBAN, DEBORAH FAUQUIER, HOLLY FEARNBACH9, JACQUELINE M. GREBMEIER, MORGAN LYNN, MANFREDI MANIZZA, etc.
▲ 鏈接：https://www.science.org/doi/full/10.1126/science.adi1847
▲ 摘要：
氣候變化正在影響廣泛的全球系統，其中極地生態系統的變化最為迅速。盡管氣候影響最直接地影響低營養水平和短命物種，但尚不清楚長壽和流動物種將如何應對快速的極地變暖，因為它們可能在適應新條件的同時具有適應生態破壞的短期能力。
研究發現，一個標志性的、高度移動的極地相關物種的種群動態與北極獵物的可用性和進入覓食區域的途徑密切相關。
當低獵物生物量與高冰蓋同時發生時，灰鯨經歷了重大的死亡事件，每次都會使種群減少15%到25%。這表明，隨著北極變暖，即使是移動的、長壽的物種也對動態和不斷變化的環境很敏感。
▲ 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.
生命科學Life Science
Direct observation of glycans bonded to proteins and lipids at the single-molecule level
在單分子水平上直接觀察與蛋白質和脂質結合的聚糖
▲ 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
▲ 鏈接：https://www.science.org/doi/full/10.1126/science.adh3856
▲ 摘要：
許多蛋白質，特別是那些由真核細胞分泌的蛋白質，有糖鏈附著，以促進質量控制或介導蛋白質—蛋白質或細胞—細胞相互作用。
這些糖通常是復雜和異質的，用傳統的結構或生物物理方法來研究是具有挑戰性的。研究表明，可以使用單分子原子力顯微鏡直接對附著在肽和脂質的聚糖進行成像。
這些生物分子可以通過溫和的電噴霧沉積應用到表面上，如果必要的話，可以通過操縱來拉伸結構區域。作者觀察到不同的聚糖結構和成像的大片段蛋白質，包括密集糖基化粘蛋白。
▲ Abstract