雷竞技-《科学》（20240816出版）一周论文导读—新闻—科学网

空气不变性依然是钠层状氧化物（NLOs）贸易化的一年夜障碍。在此，我们注解了水蒸气只有别离与二氧化碳或氧气耦应时，在NLOs的粉碎性酸降解和氧化降解中起要害感化。

定量阐发注解，下降离子电位和钠含量综合影响的阳离子竞争系数(η)和增年夜粒径可以加强聚合物的抗酸腐蚀能力，而利用高电位氧化还原对可以消弭氧化降解。这些发现说明了潜伏的空气恶化机制，并使空气不变NLOs的设计公道化。

▲ Abstract：

Air sensitivity remains a substantial barrier to the commercialization of sodium (Na)–layered oxides (NLOs). We show here that water vapor plays a pivotal role in initiating destructive acid and oxidative degradations of NLOs only when coupled with carbon dioxide or oxygen, respectively. Quantification analysis revealed that reducing the defined cation competition coefficient (η), which integrates the effects of ionic potential and sodium content, and increasing the particle size can enhance the resistance to acid attack, whereas using high-potential redox couples can eliminate oxidative degradation. These findings elucidate the underlying air deterioration mechanisms and rationalize the design of air-stable NLOs.

天文学Astronomy

Ruthenium isotopes show the Chicxulub impactor was a carbonaceous-type asteroid

钌同位素注解希克苏鲁伯陨石是一颗碳质小行星

▲ 作者：MARIO FISCHER-G?DDE, JONAS TUSCH et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adk4868

▲ 摘要：

6600万年前产生在墨西哥希克苏鲁伯的一次陨石撞击，发生了一个标记着白垩纪和古近纪分界限的地层。这一地层含有高浓度的铂族元素，包罗钌。

我们丈量了三个白垩纪—古近纪鸿沟地址的样品中的钌同位素，别的五个产生在3600万到4.7亿年前的撞击，和35亿到32亿年前的撞击球体层。我们的数据注解，希克苏鲁伯撞击物是一颗构成在木星轨道以外的碳质小行星。

别的五个撞击布局的同位素特点与构成在离太阳更近的处所的硅质小行星更一致。泰初宙球粒层样品与地球吸积最后阶段含碳小行星的撞击相一致。

▲ Abstract：

An impact at Chicxulub, Mexico, oc雷竞技curred 66 million years ago, producing a global stratigraphic layer that marks the boundary between the Cretaceous and Paleogene eras. That layer contains elevated concentrations of platinum-group elements, including ruthenium. We measured ruthenium isotopes in samples taken from three Cretaceous-Paleogene boundary sites, five other impacts that occurred between 36 million to 470 million years ago, and ancient 3.5-billion- to 3.2-billion-year-old impact spherule layers. Our data indicate that the Chicxulub impactor was a carbonaceous-type asteroid, which had formed beyond the orbit of Jupiter. The five other impact structures have isotopic signatures that are more consistent with siliceous-type asteroids, which formed closer to the Sun. The ancient spherule layer samples are consistent with impacts of carbonaceous-type asteroids during Earth’s final stages of accretion.

物理学Physics

Quantum state tracking and control of a single molecular ion in a thermal environment

热情况中单个份子离子的量子态跟踪与节制

▲ 作者：YU LIU, JULIAN SCHMIDT et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.ado1001

▲ 摘要：

在此，我们陈述单个份子在分歧状况（“跳跃”）之间的热辐射驱动转换的及时不雅察。我们经由过程微波驱动的改变逆转了这些“跳跃”，使得份子逗留在选定状况的时候耽误了20倍。

丈量的跃迁速度在热情况中显示出各向异性，这注解利用单份子作为情况场强度的原位探针是可能的。我们的状况检测和把持方式利用普遍，增进它们在量子科学、份子物理和离子中性化学等范畴的利用。

▲ Abstract：

Here, we report real-time observations of thermal radiation–driven transitions between individual states (“jumps”) of a single molecule. We reversed these jumps through microwave-driven transitions, which resulted in a 20-fold improvement in the time the molecule dwells in a chosen state. The measured transition rates showed anisotropy in the thermal environment, pointing to the possibility of using single molecules as in situ probes for the strengths of ambient fields. Our approaches for state detection and manipulation could apply to a wide range of species, facilitating their uses in fields including quantum science, molecular physics, and ion-neutral chemistry.

公共卫生Public Health

Mapping safe drinking water use in low- and middle-income countries

绘制低收入和中等收入国度平安饮用水利用环境地图

▲ 作者：ESTHER E. GREENWOOD, THOMAS LAUBER et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.adh9578

▲ 摘要：

取得平安饮用水是一项人权，但全球一半以上生齿平安治理饮用水办事（SMDWS）的数据是缺掉的。

我们操纵地舆空间建模方式，连系现有的家庭查询拜访数据和现有的全球地舆空间数据集，估算了135个低收入和中等收入国度（LMICs）在次国度级的SMDWS利用环境。我们估量，在2020年，中低收入国度中只有三分之一的人可使用SMDWS，粪便污染是影响近一半LMICs生齿的首要限制身分。

我们的研究成果有助在提高人们对当前全球监测方式的挑战和局限性的熟悉，并展现若何操纵全球可用的地舆空间数据来弥补数据空白，肯定LMICs的优先区域。

▲ Abstract：

Safe drinking water access is a human right, but data on safely managed drinking water services (SMDWS) is lacking for more than half of the global population. We estimate SMDWS use in 135 low- and middle-income countries (LMICs) at subnational levels with a geospatial modeling approach, combining existing household survey data with available global geospatial datasets. We estimate that only one in three people used SMDWS in LMICs in 2020 and identified fecal contamination as the primary limiting factor affecting almost half of the population of LMICs. Our results are relevant for raising awareness about the challenges and limitations of current global monitoring approaches and demonstrating how globally available geospatial data can be leveraged to fill data gaps and identify priority areas in LMICs.

生物学Biology

Structure and repair of replication-coupled DNA breaks

复制偶联DNA断裂的布局和修复

▲ 作者：Raphael Pavani, Veenu Tripathi, Kyle B. Vrtis et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.ado3867

▲ 摘要：

经由过程利用CRISPR-Cas9切割酶，我们研究了复制机制与单链断裂（最多见的内源性DNA毁伤情势之一）之间的彼此感化。我们注解了在前导链刻痕处的复制叉解体会发生切除的单端双链断裂（seDSBs），并经由过程同源重组（HR）修复。

假如这些seDSBs不克不及和时修复，相邻分叉的到来会发生双端DSB（deDSB），这可能会在HR缺点癌症中驱动基因组瘢痕。当复制叉绕过滞后链缺口时，也会直接发生deDSB。

与自力在复制发生的dedsb分歧，缺口引诱的se/deDSB的结尾切除是不依靠在BRCA1的。但是，BRCA1拮抗53BP1对RAD51丝构成的按捺。这些成果凸起了保持复制叉不变性的怪异机制。

▲ Abstract：

Using CRISPR-Cas9 nicking enzymes, we examined the interaction between the replication machinery and single-strand breaks, one of the most common forms of endogenous DNA damage. We show that replication fork collapse at leading-strand nicks generates resected single-ended double-strand breaks (seDSBs) that are repaired by homologous recombination (HR). If these seDSBs are not promptly repaired, arrival of adjacent forks creates double-ended DSBs (deDSBs), which could drive genomic scarring in HR-deficient cancers. deDSBs can also be generated directly when the replication fork bypasses lagging-strand nicks. Unlike deDSBs produced independently of replication, end resection at nick-induced seDSBs and deDSBs is BRCA1-independent. Nevertheless, BRCA1 antagonizes 53BP1 suppression of RAD51 filament formation. These results highlight distinctive mechanisms that maintain replication fork stability.

A hippocampal circuit mechanism to balance memory reactivation during sleep

睡眠中均衡记忆再激活的海马回路机制

▲ 作者：LINDSAY A. KARABA, HEATH L. ROBINSON et al.

▲ 链接：

https://www.science.org/doi/10.1126/science.ado5708

▲ 摘要：

记忆巩固触及在睡眠锐波波纹（SWRs）中活跃的海马细胞的同步再激活。若何在进修后均衡这类放电率和同步性的增添以连结收集的不变性尚不明白。

我们发现了一个由CA2锥体细胞亚群与胆囊缩短素（CCK+）篮细胞构成的海马内回路发生的收集事务，该回路在非快速眼动睡眠时代发射一系列动作电位（BARR）。在进修进程中增添勾当的CA1神经元和组件在SWRs时代被从头激活，但在BARR时代会被按捺。

在SWRs时代，最初的再激活增添经由过程睡眠恢复到基线程度。经由过程在BARRs时代缄默CCK+篮细胞来消弭这类趋向，致使CA1组装的更高同步性和记忆巩固受损。经由过程在BARRs时代缄默CCK+篮细胞来消弭这类趋向，致使CA1的更高同步性和记忆巩固受损。

▲ Abstract：

Memory consolidation involves the synchronous reactivation of hippocampal cells active during recent experience in sleep sharp-wave ripples (SWRs). How this increase in firing rates and synchrony after learning is counterbalanced to preserve network stability is not understood. We discovered a network event generated by an intrahippocampal circuit formed by a subset of CA2 pyramidal cells to cholecystokinin-expressing (CCK+) basket cells, which fire a barrage of action potentials (“BARR”) during non–rapid eye movement sleep. CA1 neurons and assemblies that increased their activity during learning were reactivated during SWRs but inhibited during BARRs. The initial increase in reactivation during SWRs returned to baseline through sleep. This trend was abolished by silencing CCK+ basket cells during BARRs, resulting in higher synchrony of CA1 assemblies and impaired memory consolidation.

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