编译｜冯维维

Science, 28 FEB 2025,VOLUME 387, ISSUE 6737

《科学》2025年2月28日，第387卷，6737期

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物理Physics

Visualizing nanoparticle surface dynamics and instabilities enabled by deep denoising

通过深度去噪实现纳米颗粒表面动态和不稳定性的可视化

▲ 作者：PETER A. CROZIER, MATAN LEIBOVICH, PIYUSH HALUAI, MAI TAN, ANDREW M. THOMAS, JOSHUA VINCENT, SREYAS MOHAN, ADRIA MARCOS MORALES, SHREYAS A. KULKARNI, AND CARLOS FERNANDEZ-GRANDA

▲链接：

https://www.science.org/doi/10.1126/science.ads2688

▲摘要：

材料的功能可能与发生在毫秒时间尺度上的原子级结构动力学有关。然而，电子显微镜成像结构具有高空间分辨率和毫秒级时间分辨率的能力往往受到较差的信噪比的限制。通过无监督深度去噪框架，研究者在中等电子剂量下观察到气体环境中金属纳米颗粒表面（氧化铈上的铂纳米颗粒）的时间分辨率低至10毫秒。

在这个时间尺度上，许多纳米颗粒表面连续地在有序和无序构型之间转换。应力场可以穿透表面以下，导致缺陷的形成和不稳定，从而使纳米颗粒具有流动性。将这种无监督去噪与原位电子显微镜相结合，极大地改善了时空表征，为探索材料的原子级结构动力学打开了新的窗口。

▲Abstract：

Materials functionalities may be associated with atomic-level structural dynamics occurring on the millisecond timescale. However, the capability of electron microscopy to image structures with high spatial resolution and millisecond temporal resolution is often limited by poor signal-to-noise ratios. With an unsupervised deep denoising framework, we observed metal nanoparticle surfaces (platinum nanoparticles on cerium oxide) in a gas environment with time resolutions down to 10 milliseconds at a moderate electron dose. On this timescale, many nanoparticle surfaces continuously transition between ordered and disordered configurations. Stress fields can penetrate below the surface, leading to defect formation and destabilization, thus making the nanoparticle fluxional. Combining this unsupervised denoiser with in situ electron microscopy greatly improves spatiotemporal characterization, opening a new window for the exploration of atomic-level structural dynamics in materials.

Curvature-guided depletion stabilizes Kagome superlattices of nanocrystals

曲率引导耗尽稳定纳米晶体的笼目超晶格

▲ 作者：SIYU WAN, XIUYANG XIA, YUTONG GAO, HEYANG ZHANG, ZHEBIN ZHANG, FANGYUE WU, XUESONG WU, DONG YANG, TONGTAO LI, AND ANGANG DONG

▲链接：

https://www.science.org/doi/10.1126/science.adu4125

▲摘要：

调节“哑铃”形纳米晶体的曲率可以控制粒子键合的方向性，从而形成各种复杂的二维超晶格。

研究者发现，这些稀土氟化物胶体的超晶格形成是由曲率引导的耗尽相互作用驱动的全局互锁自组装造成的，这是传统凸粒子难以实现的。该方法还可以稳定具有周期性空位的结构，如手性笼目晶格。

▲ Abstract：

Adjusting the curvature of dumbbell-shaped nanocrystals can control particle bonding directionality to form a variety of intricate two-dimensional superlattices. Wan et al. found that superlattice formation from these rare earth fluoride colloids results from globally interlocking self-assembly driven by curvature-guided depletion interactions that are difficult to achieve with conventional convex particles. This method could also stabilize structures with periodic vacancies, such as the chiral Kagome lattice.

化学Chemistry

Berkelium–carbon bonding in a tetravalent berkelocene

四价黑绿统中的铍碳键合

▲ 作者：DOMINIC R. RUSSO, ALYSSA N. GAISER, AMY N. PRICE, DUMITRU-CLAUDIU SERGENTU, JENNIFER N. WACKER, NICHOLAS KATZER, APPIE A. PETERSON, JACOB A. BRANSON, XIAOJUAN YU, AND STEFAN G. MINASIAN

▲链接：

https://www.science.org/doi/10.1126/science.adr3346

▲摘要：

自从在曼哈顿计划期间首次研究锕系有机金属在同位素分离中的应用以来，人们对锕系-碳键的兴趣一直存在。跨钚有机金属很少被分离和结构表征，可能是由于同位素库存有限，缺乏适当的实验室基础设施，以及所需厌氧条件的内在困难。

二茂铁是夹在两个碳环之间的铁离子，其结构的阐明是有机金属化学理论和实践的基础。在随后的几十年里，许多类似的金属夹层化合物被制备和应用。研究者将基序扩展到比铀重的放射性元素锫。

他们的实验需要在亚毫克的尺度上快速合成和表征，以补偿正在进行的衰变。光谱和理论分析支持了金属环配体和f轨道之间的共价相互作用。

▲ Abstract：

Interest in actinide–carbon bonds has persisted since actinide organometallics were first investigated for applications in isotope separation during the Manhattan Project. Transplutonium organometallics are rarely isolated and structurally characterized, likely owing to limited isotope inventories, a scarcity of suitable laboratory infrastructure, and intrinsic difficulties with the anaerobic conditions required. Elucidating the structure of ferrocene, an iron ion sandwiched between two carbon rings, was foundational to the theory and practice of organometallic chemistry. In the ensuing decades, numerous analogous metal sandwich compounds have been prepared and applied. Russo et al. now extend the motif to berkelium, a radioactive element heavier than uranium. Their experiments required rapid synthesis and characterization on a submilligram scale to compensate for the ongoing decay. Spectroscopic and theoretical analysis supported covalent interactions between the cyclic ligands and f orbitals of the metal.

Nitrogen dominates global atmospheric organic aerosol absorption

氮在全球大气有机气溶胶吸收中占主导地位

▲ 作者：YUMIN LI, TZUNG-MAY FU, JIAN ZHEN YU, AOXING ZHANG, XU YU, JIANHUAI YE, LEI ZHU, HUIZHONG SHEN, CHEN WANG, AND COLETTE L. HEALD

▲链接：

https://www.science.org/doi/10.1126/science.adr4473

▲摘要：

大气气溶胶通过散射或吸收太阳辐射来影响气候。然而，它们的进化组成和吸收作用之间的联系尚不清楚。研究者发现棕色氮，即有机气溶胶的含氮成分，在全球范围内主导着大气有机气溶胶的太阳能吸收。

他们使用一个模型来量化大气中棕色氮的分布，计算化学老化如何影响其光学特性，并量化其辐射影响。这些结果将有助于改进有机气溶胶对气候影响的归因。

▲ Abstract：

Atmospheric aerosols affect climate by either scattering or absorbing solar radiation. Li et al. found that brown nitrogen, the nitrogenous component of organic aerosols, dominates their solar absorption globally. The authors used a model to quantify the atmospheric distribution of brown nitrogen, calculated how chemical aging affects its optical properties, and quantified its radiative impacts. These results will help to improve attribution of the climate effects of organic aerosols.

植物病理学Plant Pathology

A widespread plant defense compound disarms bacterial type III injectisome assembly

一种植物防御化合物让细菌解除“武装”

▲ 作者：PEI MIAO, HAIJUN WANG, WEI WANG, ZHENGDONG WANG, HAN KE, HANGYUAN CHENG, JINJING NI, JINGNAN LIANG, YU-FENG YAO, AND XIAOGUANG LEI

▲ 链接：https://www.science.org/doi/10.1126/science.ads0377

▲摘要：

III型分泌系统（T3SS）是细菌将效应蛋白注入宿主细胞的一种机制。然而，宿主介导的毒力阻断机制，特别是代谢物阻断机制，尚不清楚。

研究者发现了一种被称为芥子酰胺的植物抗菌素，它由几种植物产生，并阻断两种细菌的T3SS功能。芥子酰胺的靶点是保守的细菌III型分泌系统注射器蛋白HrcC。芥子酰胺积累是植物防御的一部分，研究发现芥子酰胺减少的转基因植物易受细菌感染。

▲ Abstract：

The type III secretion system (T3SS) is used by bacterial species to inject effector proteins into host cells. However, the mechanisms of host-mediated blockage of virulence, especially by metabolites, are not well understood. Miao et al. uncovered a phytoalexin called erucamide that is produced by several plant species and blocks T3SS function in two bacterial species. The target of erucamide is the conserved bacterial type III secretion system syringe protein HrcC. Erucamide accumulation is part of plant defense, and transgenic plants with reduced erucamide were found to be susceptible to bacterial infection.

Plant pathogenic fungi hijack phosphate signaling with conserved enzymatic effectors

植物病原真菌用保守的酶效应物劫持磷酸盐信号

▲ 作者：CARL L. MCCOMBE, ALEX WEGNER, LOUISA WIRTZ, CHENIE S. ZAMORA, FLORENCIA CASANOVA, SHOUVIK ADITYA , JULIAN R. GREENWOOD, SAMUEL DE PAULA, ELEANOR ENGLAND, AND ULRICH SCHAFFRATH

▲链接：

https://www.science.org/doi/10.1126/science.adl5764

▲摘要：

植物病原体通常会释放蛋白质以靶向宿主机制，从而提高其感染成功率。研究者人分析了NUDIX蛋白家族。该家族存在于多种病原体中，并针对多种植物物种。

他们发现真菌病原体可以利用NUDIX蛋白通过破坏植物感知自身无机磷酸盐状态的能力来欺骗植物。NUDIX蛋白水解肌醇焦磷酸，这是植物细胞监测的主要磷酸化合物。如果植物专注于生长和营养，那么它可能不太能够激活免疫反应。

▲ Abstract：

Plant pathogens often release proteins to target host machinery and increase their infection success. McCombe et al. examined the NUDIX family of proteins, which are found in diverse pathogens and target multiple plant species. They found that fungal pathogens can use NUDIX proteins to trick plants by disrupting their ability to sense their own inorganic phosphate status. NUDIX proteins hydrolyze inositol pyrophosphate, which is the main phosphate compound monitored by plant cells. If the plant focuses on growth and nutrition, then it may be less able to activate immune responses.