《自然》（20240627出版）一周論文導讀

編譯｜李言

Nature, 27 June 2024, Volume 630 Issue 8018

《自然》,  2024年6月27日，第630卷，8018期

材料科學Materials Science

Large-area, self-healing block copolymer membranes for energy conversion

用于能量轉換的大面積自愈嵌段共聚物膜

▲ 作者：Christian C. M. Sproncken, Peng Liu et.al

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07481-2

▲ 摘要：

在此，我們介紹一種自組裝策略，該策略使用水兩相系統的界面來模板化和穩定擴展面積超過10 cm²且無缺陷的分子薄膜（約35 nm）仿生嵌段共聚物雙層。

這些薄膜可自我修復，且對離子通過的屏障功能（比電阻約為1 MΩ cm²）接近磷脂膜。薄膜的流動性使分子載體能夠進行直接的功能化，這些分子載體具有比鈉離子更精細的選擇性，可以將鉀離子沿濃度梯度向下穿梭。這種離子選擇性使得在模擬電射線的電器官的裝置中，在NaCl和KCl的等摩爾溶液能夠產生電能。

▲ Abstract：

Here we introduce a self-assembly strategy that uses the interface of an aqueous two-phase system to template and stabilize molecularly thin (approximately 35 nm) biomimetic block copolymer bilayers of scalable area that can exceed 10 cm² without defects. These membranes are self-healing, and their barrier function against the passage of ions (specific resistance of approximately 1 MΩ cm²) approaches that of phospholipid membranes. The fluidity of these membranes enables straightforward functionalization with molecular carriers that shuttle potassium ions down a concentration gradient with exquisite selectivity over sodium ions. This ion selectivity enables the generation of electric power from equimolar solutions of NaCl and KCl in devices that mimic the electric organ of electric rays.

海洋科學Marine Science

Observations of diapycnal upwelling within a sloping submarine canyon

對傾斜海底峽中谷底旋上升流的觀測

▲ 作者：Bethan L. Wynne-Cattanach, Nicole Couto et.al

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07411-2

▲ 摘要：

在此，我們展示以每天100米的速率沿等高線上升的激烈近底部上升流，加上近邊界和內部流體的絕熱交換。這些觀測是通過在傾斜海底峽谷內靠近海底釋放一種染料進行的，它們為深海中以底部為中心的激烈底旋上升流提供了直接證據。這支持了先前的觀點，即混合的地形特征（如峽谷）會在全球范圍內導致顯著的上升流。我們觀測到的上升流速率大約比全球凈上升流的平均值（約30 × 10⁶ m³ s^-1）高10000倍。

▲ Abstract：

Here we show vigorous near-bottom upwelling across isopycnals at a rate of the order of 100 metres per day, coupled with adiabatic exchange of near-boundary and interior fluid. These observations were made using a dye released close to the seafloor within a sloping submarine canyon, and they provide direct evidence of strong, bottom-focused diapycnal upwelling in the deep ocean. This supports previous suggestions that mixing at topographic features, such as canyons, leads to globally significant upwelling. The upwelling rates observed were approximately 10,000 times higher than the global average value required for approximately 30 × 10⁶ m³ s^-1 of net upwelling globally.

Rhizobia–diatom symbiosis fixes missing nitrogen in the ocean

根瘤菌—硅藻共生可固定海洋中缺失的氮

▲ 作者：Bernhard Tschitschko, Mertcan Esti et.al

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07495-w

▲ 摘要：

在此，我們報告一種非藍藻固氮共生體的發現——Candidatus Tectiglobus diatomicola，它為其硅藻宿主提供固定氮以換取光合碳。這種固氮共生體屬于根瘤菌綱，它與單細胞硅藻的結合擴大了已知宿主的范圍，超出了眾所周知的陸地固氮根瘤菌與豆科的共生關系。

我們的研究結果表明，在北大西洋熱帶地區，根瘤菌—硅藻共生可以提供與藍藻固氮一樣多的固定氮，并且它們可能負責在藍藻太稀少而無法解釋測量率的廣闊海洋地區固定氮。

▲ Abstract：

Here we report the discovery of a non-cyanobacterial N₂-fixing symbiont, ‘Candidatus Tectiglobus diatomicola’, which provides its diatom host with fixed nitrogen in return for photosynthetic carbon. The N₂-fixing symbiont belongs to the order Rhizobiales and its association with a unicellular diatom expands the known hosts for this order beyond the well-known N₂-fixing rhizobia–legume symbioses on land. Our results show that the rhizobia–diatom symbioses can contribute as much fixed nitrogen as can cyanobacterial N₂ fixers in the tropical North Atlantic, and that they might be responsible for N₂ fixation in the vast regions of the ocean in which cyanobacteria are too rare to account for the measured rates.

醫學Medicine

Sleep loss diminishes hippocampal reactivation and replay

睡眠不足會減少海馬體的再激活和重放能力

▲ 作者：Bapun Giri, Nathaniel Kinsky, Utku Kaya, Kourosh Maboudi, Ted Abel & Kamran Diba

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07538-2

▲ 摘要：

在這里，我們記錄了大鼠在經歷迷宮探索、睡眠和睡眠剝奪后進行恢復性睡眠， 12小時的CA1神經元活動。我們發現，在睡眠剝奪期間，海馬尖波漣漪（SWRs）表現出持續或更高的頻率，但功率較低，頻率波動較高。錐體細胞在睡眠剝奪時表現出持續的放電，而在睡眠狀態時則表現出放電減少，但無論睡眠狀態如何，它們在SWRs期間的放電率都是相似的。盡管在睡眠剝奪期間有強大的放電和豐富的SWRs，但我們發現在這些時期神經元放電模式的再激活和重放減少了，與自由睡眠相比，在某些情況下甚至完全消失了。在恢復性睡眠后，大腦的再激活會部分反彈，但沒有達到自然睡眠時的水平。

▲ Abstract：

Here we recorded CA1 neuronal activity over 12 h in rats across maze exploration, sleep and sleep deprivation, followed by recovery sleep. We found that sharp-wave ripples (SWRs) showed sustained or higher rates during sleep deprivation but with lower power and higher frequency ripples. Pyramidal cells exhibited sustained firing during sleep deprivation and reduced firing during sleep, yet their firing rates were comparable during SWRs regardless of sleep state. Despite the robust firing and abundance of SWRs during sleep deprivation, we found that the reactivation and replay of neuronal firing patterns was diminished during these periods and, in some cases, completely abolished compared to ad libitum sleep. Reactivation partially rebounded after recovery sleep but failed to reach the levels found in natural sleep. 

考古學Archaeology

Ancient genomes reveal insights into ritual life at Chichén Itzá

古代基因組揭示奇琴伊察的祭祀生活

▲ 作者：Rodrigo Barquera, Oana Del Castillo-Chávez et.al

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07509-7

▲ 摘要：

在此，我們展示了從64個可追溯到公元500—900年左右的亞成年個體中獲得的全基因組數據，這些個體是奇琴伊察祭祀中心的神圣天坑附近的一個地下群葬中發現的。遺傳分析表明，所分析的個體均為男性，有幾個個體親緣關系密切，包括兩對同卵雙胞胎。

雙胞胎因體現了神和英雄之間的二元性，在瑪雅和更廣泛的中美洲神話中占有突出地位，但直到現在，他們還沒有在古代瑪雅人的殯葬中被識別出來。除了與人類免疫有關的某些遺傳位點（包括人類白細胞抗原復合物）外，該地區現代人的基因對比顯示出與奇琴伊察古代居民的遺傳具有連續性，這可能是殖民時期傳入該地區的傳染病而導致的適應的信號。

▲ Abstract：

Here we present genome-wide data obtained from 64 subadult individuals dating to around AD 500–900 that were found in a subterranean mass burial near the Sacred Cenote (sinkhole) in the ceremonial centre of Chichén Itzá. Genetic analyses showed that all analysed individuals were male and several individuals were closely related, including two pairs of monozygotic twins. Twins feature prominently in Mayan and broader Mesoamerican mythology, where they embody qualities of duality among deities and heroes, but until now they had not been identified in ancient Mayan mortuary contexts. Genetic comparison to present-day people in the region shows genetic continuity with the ancient inhabitants of Chichén Itzá, except at certain genetic loci related to human immunity, including the human leukocyte antigen complex, suggesting signals of adaptation due to infectious diseases introduced to the region during the colonial period.

管理學Management Science

Hybrid working from home improves retention without damaging performance

混合辦公可以在不影響工作表現的情況下提高員工留存率

▲ 作者：Nicholas Bloom, Ruobing Han & James Liang

▲ 鏈接：

https://www.nature.com/articles/s41586-024-07500-2

▲ 摘要：

在此，我們進行了一項為期六個月的隨機對照試驗，調查了2021—2022年間一家中國科技公司1612名員工在家混合辦公的情況。我們發現，混合工作提高了工作滿意度，并將辭職率降低了三分之一。對于非管理人員、女性員工和通勤時間較長的人來說，辭職率的下降非常顯著。零等效性測試表明，在今后兩年的審查中，混合工作不影響績效成績。我們沒有發現任何證據表明，在接下來的兩年里，無論是總體還是在任何主要的員工群體中，晉升方面會存在差異。

最后，零等效性測試也表明，混合辦公對計算機工程師員工編寫代碼沒有影響。我們還發現，在實驗中，395位管理者改變了他們對混合辦公對生產力影響的看法，從實驗前的負面影響（平均為- 2.6%）到實驗后感知到的積極影響（+1.0%）。這些結果表明，每周在家工作兩天的混合辦公計劃不會降低員工的表現。

▲ Abstract：

Here we ran a six-month randomized control trial investigating the effects of hybrid working from home on 1,612 employees in a Chinese technology company in 2021–2022. We found that hybrid working improved job satisfaction and reduced quit rates by one-third. The reduction in quit rates was significant for non-managers, female employees and those with long commutes. Null equivalence tests showed that hybrid working did not affect performance grades over the next two years of reviews. We found no evidence for a difference in promotions over the next two years overall, or for any major employee subgroup. Finally, null equivalence tests showed that hybrid working had no effect on the lines of code written by computer-engineer employees. We also found that the 395 managers in the experiment revised their surveyed views about the effect of hybrid working on productivity, from a perceived negative effect (2.6% on average) before the experiment to a perceived positive one (+1.0%) after the experiment. These results indicate that a hybrid schedule with two days a week working from home does not damage performance.