Science,24 JAN 2025, VOL 387, ISSUE 6732
《科學》2025年1月24日，第387卷，6732期
材料科學Materials Science
Ductilization of 2.6-GPa alloys via short-range ordered interfaces and supranano precipitates
短程有序界面和超納析出相實現2.6GPa級合金的優異均勻延伸率
▲ 作者：YONG-QIANG, WEN-HAO CHA et al.
▲鏈接：
https://www.science.org/doi/10.1126/science.adr4917
▲摘要：
我們提出了一種針對晶粒內部和晶界區域的超納米（<10納米）和短程有序化設計。這種設計應用于基于釩、鈷和鎳的細晶合金，并添加了鎢、銅、鋁和硼。通過短程有序化在晶界附近的偏聚，顯著實現了晶界相關的強化和塑化機制。
此外，尺寸較大的超納米有序化對位錯和層錯具有更強的釘扎效應，這些位錯和層錯在塑性變形過程中在晶粒內部持續增殖和累積。這些機制促使合金在10%應變下斷裂時，流變應力持續增加，達到2.6GPa的拉伸應力。
▲ Abstract：
We present a supranano (<10 nanometers) and short-range ordering design for grain interiors and grain boundary regions, respectively, in fine-grained alloys based on vanadium, cobalt, and nickel, with additions of tungsten, copper, aluminum, and boron. The pronounced grain boundary–related strengthening and ductilization mechanism is realized through segregation of the short-range ordering near the grain boundary. Furthermore, the supranano ordering with a larger size has an enhanced pinning effect for dislocations and stacking faults, multiplied and accumulated in grain interiors during plastic deformation. These mechanisms promote continuously increased flow stress until fracture of the alloy at 10% strain with 2.6-gigapascal tensile stress.
Photo-induced chirality in a nonchiral crystal
非手性晶體中的光誘導手性
▲ 作者：Z. ZENG, M. F?RST et al.
▲鏈接：
https://www.science.org/doi/10.1126/science.adr4713
▲摘要：
在此，我們展示了通過太赫茲脈沖輻照，可以在非手性的壓電材料硼磷酸鹽（BPO4）中誘導出任意手性的手性特征。兩個正交的、簡并的振動模式中任何一個的共振激發決定了誘導手性序參數的信號。
光誘導相的光學活性與典型手性物質α-石英的靜態值相當。我們的研究結果為復雜材料中非平衡量子現象的調控提供了新的前景。
▲ Abstract：
Here, we show that chirality of either handedness can be induced in the nonchiral piezoelectric material boron phosphate (BPO4) by irradiation with terahertz ulses. Resonant excitation of either one of two orthogonal, degenerate vibrational modes determines the sign of the induced chiral order parameter. The optical activity of the photo-induced phases is comparable to the static value of prototypical chiral α-quartz. Our findings offer new prospects for the control of out-of-equilibrium quantum phenomena in complex materials.
生態學Ecology
Variable impacts of land-based climate mitigation on habitat area for vertebrate diversity
陸地氣候變化減緩措施對脊椎動物多樣性棲息地面積的多種影響
▲ 作者：JEFFREY R. SMITH, EVELYN M. BEAURY et al.
▲鏈接：
https://www.science.org/doi/10.1126/science.adm9485
▲摘要：
在此，我們對14234種脊椎動物的氣候和棲息地需求進行了建模，并表明這些策略對物種棲息地面積的影響并非主要通過氣候變化減緩實現，而是通過棲息地轉換。
在不同地區，通過土地覆蓋變化和氣候變化減緩，重新造林能為物種提供更多的棲息地，而造林和生物能源作物種植所導致的棲息地喪失通常超過了氣候變化減緩帶來的好處。這項研究表明，如何以及在哪里部署基于土地的減緩策略，才不會無意中減少全球生物多樣性的棲息地面積。
▲ Abstract：
Here, we modeled the climate and habitat requirements of 14,234 vertebrate species and show that the impact of these strategies on species’ habitat area tends not to arise through climate mitigation, but rather through habitat conversion. Across locations, reforestation tends to provide species more habitat through both land-cover change and climate mitigation, whereas habitat loss from afforestation and bioenergy cropping typically outweighs the climate mitigation benefits. This work shows how and where land-based mitigation strategies can be deployed without inadvertently reducing the area of habitat for global biodiversity.
Antarctic krill vertical migrations modulate seasonal carbon export
南極磷蝦的垂直遷移行為調節季節性碳輸出
▲ 作者：A. J. R. SMITH, S. WOTHERSPOON et al.
▲鏈接：
https://www.science.org/doi/10.1126/science.adq5564
▲摘要：
通過消耗表層浮游植物并在深海排泄，海洋生物的垂直遷移行為促進了碳的輸出。然而，由于生物地球化學模型缺乏觀測數據，導致對像南極磷蝦（Euphausia superba）一樣的遷移生物的碳循環過程的描述過于簡化。利用在東南極地區一年的聲學觀測數據構建的數值模型，我們估算出南極磷蝦糞便顆粒的總顆粒有機碳（POC）通量為每平方米每天9.68毫克碳。
最多有25%的磷蝦遷移超過200米的深度，且這一過程具有強烈的季節性特征，將總磷蝦POC通量中不到10%的部分（每平方米每天1.28毫克碳）輸送到深海。準確的碳通量估算對于制定氣候政策和減排策略至關重要，如果未能掌握到這種季節性特征，包含垂直遷移過程的模型可能會高估碳輸出。
▲ Abstract：
Vertical migrations by marine organisms contribute to carbon export by consumption of surface phytoplankton followed by defecation in the deep ocean. However, biogeochemical models lack observational data, leading to oversimplified representation of carbon cycling by migrating organisms, such as Antarctic krill (Euphausia superba). Using a numerical model informed by 1 year of acoustic observations in the East Antarctic, we estimated the total particulate organic carbon (POC) flux from krill fecal pellets to be 9.68 milligrams of carbon per square meter per day (mg C m?2day?1). A maximum of 25% of krill migrated to depths >200 m with a strong seasonality component, transporting <10% of the total krill POC flux (1.28 mg Cm?2day?1) to the deep ocean. Accurate carbon flux estimates are essential to inform climate policy and mitigation strategies, and models that include vertical migration will overestimate carbon export if this seasonality is not captured.
生物學Biology
Identification of the subventricular tegmental nucleus as brainstem reward center
腦室下被蓋核是腦干的獎賞中樞
▲ 作者：KRISZTIáN ZICHó, BOLDIZSáR ZSOLT BALOG et al.
▲鏈接：
https://www.science.org/doi/10.1126/science.adr2191
▲摘要：
我們認為腦室下被蓋核（SVTg）是腦干的獎賞中樞。在小鼠身上，獎勵及其預期能夠激活SVTg，而SVTg的刺激會導致位置偏好、焦慮減少以及伏隔核多巴胺的釋放。小鼠會自行刺激SVTg，而該區域也可以被新皮層直接激活，從而有效抑制與抑郁相關聯的側背側丘腦。
這種機制或許也能解釋為什么抑制SVTg會導致厭惡情緒的增加以及恐懼感的增強。這些發現的轉化相關性得到了大鼠、猴和人類腦干研究的證據支持，從而確立了SVTg作為獎賞處理、情緒價值和動機的關鍵樞紐。
▲ Abstract：
We identified the subventricular tegmental nucleus (SVTg) as a brainstem reward center. In mice, reward and its prediction activate the SVTg, and SVTg stimulation leads to place preference, reduced anxiety, and accumbal dopamine release. Mice self-stimulate the SVTg, which can also be activated directly by the neocortex, resulting in effective inhibition of the lateral habenula, a region associated with depression. This mechanism may also explain why SVTg suppression induces aversion and increases fear. The translational relevance of these findings is supported by evidence in the rat, monkey, and human brainstem, establishing SVTg as a key hub for reward processing, emotional valence, and motivation.
A single gene orchestrates androgen variation underlying male mating morphs in ruffs
單個基因調控雄性鷸求偶形態的雄激素差異
▲ 作者：JASMINE L. LOVELAND, ALEX ZEMELLA et al.
▲鏈接：
https://www.science.org/doi/10.1126/science.adp5936
▲摘要：
我們發現在鷸鳥（ruff sandpipers）的三種雄性求偶形態之間，血液中雄激素的差異與17β-羥基類固醇脫氫酶2（HSD17B2）有關。該酶由決定這些形態的超基因中的一個基因編碼。低睪酮雄性個體的血液中HSD17B2的表達水平高于高睪酮雄性個體，同時在與社會行為和睪酮生成相關的大腦區域中也是如此。
衍生的HSD17B2同工酶在高睪酮雄性中缺失，但在低睪酮雄性中會被優先表達。它們將睪酮轉化為雄烯二酮的速度比同工酶更快。因此，單個基因在調控、序列和結構上的進化變化共同引入了生殖表型背后的內分泌差異。
▲ Abstract：
We show that differences in circulating androgens between the three male mating morphs in ruff sandpipers are linked to 17-beta hydroxysteroid dehydrogenase 2 (HSD17B2), encoded by a gene within the supergene that determines the morphs. Low-testosterone males had higher HSD17B2 expression in blood than high-testosterone males, as well as in brain areas related to social behaviors and testosterone production. Derived HSD17B2 isozymes, which are absent in high-testosterone males but preferentially expressed in low-testosterone males, converted testosterone to androstenedione faster than the ancestral isozyme. Thus, a combination of evolutionary changes in regulation, sequence, and structure of a single gene introduces endocrine variation underlying reproductive phenotypes.
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