《科學》（20240816出版）一週論文導讀

來源：媒體滾動

編譯|李言

Science, 16 AUG 2024, Volume 385 Issue 6710

《科學》2024年8月16日，第385卷，6710期

化學Chemistry

Decoupling the air sensitivity of Na-layered oxides

解耦鈉層氧化物的空氣穩定性

▲ 作者：YANG YANG, ZAIFA WANG et al.

▲ 鏈接：

https://www.science.org/doi/10.1126/science.adm9223

▲ 摘要：

空氣穩定性仍然是鈉層狀氧化物（NLOs）商業化的一大障礙。在此，我們表明了水蒸氣只有分別與二氧化碳或氧氣耦合時，在NLOs的破壞性酸降解和氧化降解中起關鍵作用。

定量分析表明，降低離子電位和鈉含量綜合影響的陽離子競爭係數(η)和增大粒徑可以增強聚合物的抗酸侵蝕能力，而使用高電位氧化還原對可以消除氧化降解。這些發現闡明瞭潛在的空氣惡化機制，並使空氣穩定NLOs的設計合理化。

▲ 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.

天文學Astronomy

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

釕同位素表明希克蘇魯伯隕石是一顆碳質小行星

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

▲ 鏈接：

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

▲ 摘要：

6600萬年前發生在墨西哥希克蘇魯伯的一次隕石撞擊，產生了一個標誌着白堊紀和古近紀分界線的地層。這一地層含有高濃度的鉑族元素，包括釕。

我們測量了三個白堊紀—古近紀邊界地點的樣品中的釕同位素，另外五個發生在3600萬到4.7億年前的撞擊，以及35億到32億年前的撞擊球體層。我們的數據表明，希克蘇魯伯撞擊物是一顆形成於木星軌道之外的碳質小行星。

另外五個撞擊結構的同位素特徵與形成於離太陽更近的地方的硅質小行星更一致。太古宙球粒層樣品與地球吸積最後階段含碳小行星的撞擊相一致。

▲ Abstract：

An impact at Chicxulub, Mexico, occurred 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.

物理學Physics

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

熱環境中單個分子離子的量子態跟蹤與控制

▲ 作者：YU LIU, JULIAN SCHMIDT et al.

▲ 鏈接：

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

▲ 摘要：

在此，我們報告單個分子在不同狀態（“跳躍”）之間的熱輻射驅動轉換的實時觀察。我們通過微波驅動的轉變逆轉了這些“跳躍”，使得分子停留在選定狀態的時間延長了20倍。

測量的躍遷速率在熱環境中顯示出各向異性，這表明使用單分子作爲環境場強度的原位探針是可能的。我們的狀態檢測和操縱方法應用廣泛，促進它們在量子科學、分子物理和離子中性化學等領域的應用。

▲ 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.

公共衛生Public Health

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

繪製低收入和中等收入國家安全飲用水使用情況地圖

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

▲ 鏈接：

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

▲ 摘要：

獲得安全飲用水是一項人權，但全球一半以上人口安全管理飲用水服務（SMDWS）的數據是缺失的。

我們利用地理空間建模方法，結合現有的家庭調查數據和現有的全球地理空間數據集，估算了135個低收入和中等收入國家（LMICs）在次國家級的SMDWS使用情況。我們估計，在2020年，中低收入國家中只有三分之一的人可以使用SMDWS，糞便污染是影響近一半LMICs人口的主要限制因素。

我們的研究結果有助於提高人們對當前全球監測方法的挑戰和侷限性的認識，並展示如何利用全球可用的地理空間數據來填補數據空白，確定LMICs的優先區域。

▲ 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.

生物學Biology

Structure and repair of replication-coupled DNA breaks

複製偶聯DNA斷裂的結構和修復

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

▲ 鏈接：

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

▲ 摘要：

通過使用CRISPR-Cas9切割酶，我們研究了複製機制與單鏈斷裂（最常見的內源性DNA損傷形式之一）之間的相互作用。我們表明了在前導鏈刻痕處的複製叉崩潰會產生切除的單端雙鏈斷裂（seDSBs），並通過同源重組（HR）修復。

如果這些seDSBs不能及時修復，相鄰分叉的到來會產生雙端DSB（deDSB），這可能會在HR缺陷癌症中驅動基因組瘢痕。當複製叉繞過滯後鏈缺口時，也會直接產生deDSB。

與獨立於複製產生的dedsb不同，缺口誘導的se/deDSB的末端切除是不依賴於BRCA1的。然而，BRCA1拮抗53BP1對RAD51絲形成的抑制。這些結果突出了維持複製叉穩定性的獨特機制。

▲ 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

睡眠中平衡記憶再激活的海馬迴路機制

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

▲ 鏈接：

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

▲ 摘要：

記憶鞏固涉及在睡眠銳波波紋（SWRs）中活躍的海馬細胞的同步再激活。如何在學習後平衡這種放電率和同步性的增加以保持網絡的穩定性尚不明確。

我們發現了一個由CA2錐體細胞亞羣與膽囊收縮素（CCK+）籃細胞形成的海馬內迴路產生的網絡事件，該回路在非快速眼動睡眠期間發射一系列動作電位（BARR）。在學習過程中增加活動的CA1神經元和組件在SWRs期間被重新激活，但在BARR期間會被抑制。

在SWRs期間，最初的再激活增加通過睡眠恢復到基線水平。通過在BARRs期間沉默CCK+籃細胞來消除這種趨勢，導致CA1組裝的更高同步性和記憶鞏固受損。通過在BARRs期間沉默CCK+籃細胞來消除這種趨勢，導致CA1的更高同步性和記憶鞏固受損。

▲ 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.