编译|冯维维
science, 1 november 2024, volume 386, issue 6721
《科学》2024年11月1日，第386卷，6721期
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生物学biology
a molecular mechanism for bright color variation in parrots
鹦鹉鲜艳颜色变化的分子机制
▲ 作者：roberto arbore, soraia barbosa, jindich brejcha, yohey ogawa, yu liumicha?l p. j. nicola?, paulo pereira, stephen j. sabatino, alison cloutier, and miguel carneiro
▲链接：
https://www.science.org/doi/10.1126/science.adp7710
▲摘要：
众所周知，鹦鹉的鲜艳颜色是由一种叫作鹦鹉黄嘌呤的色素决定的，但这些颜色的分子基础仍然未知。arbore等人使用基因表达、染色质可及性和全基因组关联研究来确定暗色鹦鹉红色和黄色的遗传基础。
研究者在一种参与脂肪醛氧化的酶附近发现了一种假定的因果变异，并在酵母中测试了这种基因，以确认其产生色素变化的能力。研究中广泛的生化和遗传学工作有助于人们了解非模式生物的颜色，为未来对鹦鹉和其他鸟类色素沉着的研究打开大门。
▲ abstract：
the bright coloration of parrots is known to be determined by pigments known as psittacofulvins, but the molecular basis of these colors is still unknown. arbore et al. used gene expression, chromatin accessibility, and genome-wide association studies to identify the genetic underpinning of red and yellow coloration in the dusky lory. the authors identified a putative causal variant near an enzyme involved in fatty aldehyde oxidation and tested this gene in yeast to confirm its ability to produce a pigment change. the extensive biochemical and genetics work in this study aids in our understanding of coloration in a nonmodel organism, opening the door for future studies into parrot and other avian pigmentation
acoustic cognitive map–based navigation in echolocating bats
蝙蝠的回声定位声学认知地图导航
▲ 作者：aya goldshtein, xing chen, eran amichai, arjan boonman, lee harten, omer yinon, yotam orchan, ran nathan, sivan toledo, and yossi yovel
▲链接：
https://www.science.org/doi/10.1126/science.adn6269
▲摘要：
蝙蝠以其利用回声定位躲避障碍物和确定方向的能力而闻名。然而，蝙蝠在多大程度上利用它们高度局部和定向的回声定位进行千米范围的导航是未知的。研究者转移了野生库尔氏pipistrelle蝙蝠，并在操纵它们的视觉、磁和嗅觉的同时跟踪它们的归航能力，并使用一种新的反向gps系统准确地跟踪它们。
研究表明，蝙蝠可以在移动后识别它们的位置，并仅使用回声定位进行几公里的基于地图的导航。这一观点得到了大规模回声定位模型的进一步支持，该模型揭示了蝙蝠如何利用环境声学信息进行基于声学认知地图的导航。研究还表明，当使用回声定位和视觉时，导航得到了改善。
▲ abstract：
bats are known for their ability to use echolocation for obstacle avoidance and orientation. however, the extent to which bats utilize their highly local and directional echolocation for kilometer-scale navigation is unknown. in this study, we translocated wild kuhl’s pipistrelle bats and tracked their homing abilities while manipulating their visual, magnetic, and olfactory sensing and accurately tracked them using a new reverse gps system. we show that bats can identify their location after translocation and conduct several-kilometer map-based navigation using solely echolocation. this proposition was further supported by a large-scale echolocation model disclosing how bats use environmental acoustic information to perform acoustic cognitive map–based navigation. we also demonstrate that navigation is improved when using both echolocation and vision.
化学chemistry
a solution to the anti-bredt olefin synthesis problem
反布雷特烯烃合成问题的解决方法
▲ 作者：luca mcdermott, zach g. walters, sarah a. french, allison m. clark, jiaming ding, andrew v. kelleghan, k. n. houk, and neil k. garg
▲链接：
https://www.science.org/doi/10.1126/science.adq3519
▲摘要：
一百年前，朱利叶斯·布雷特发表了一项观察结果：某些分子将几个相邻的碳中心限制在特定的非平面排列中，它们之间不能形成双键。这些假想的双键被称为“反布雷特”烯烃，尽管偶尔会有相反的暗示，但它们是不可接近的学说仍然普遍存在。
mcdermott等人现在报告了一种普遍策略，将这些烯烃制备为可在环加成反应中捕获的短暂中间体。该协议依赖于前体形成硅氟键的驱动力，这类似于用于获取紧张芳烃的方法。
▲ abstract：
one hundred years ago, julius bredt published an observation that certain molecules that constrained several adjacent carbon centers in a particular nonplanar arrangement could not form double bonds between them. these hypothetical double bonds became known as “anti-bredt olefins, and the doctrine that they were inaccessible remains widespread even with the occasional hint to the contrary. mcdermott et al. now report a general strategy to prepare these olefins as fleeting intermediates that can be captured in cycloaddition reactions. the protocol relies on the driving force of silicon-fluorine bond formation from a precursor, which is akin to approaches used to access strained aromatics.
cooperative adsorbate binding catalyzes high-temperature hydrogen oxidation on palladium
协同吸附结合催化钯的高温氢氧化
▲ 作者：michael schwarzer, dmitriy borodin, yingqi wang, jan fingerhut, theofanis n. kitsopoulos, daniel j. auerbach, hua guo, and alec m. wodtke
▲链接：
https://www.science.org/doi/10.1126/science.adk1334
▲摘要：
解释非均相催化剂加速反应性的原子尺度结构通常只在高温高压的反应条件下形成，这使得它们不可能用低温、超高真空的方法观察到。研究者提出了在广泛的表面浓度和高温下钯催化氢氧化的速度分辨动力学测量。
速率表现出对氧覆盖和台阶密度的复杂依赖，这可以用密度泛函和基于过渡态理论的动力学模型来定量解释，该模型涉及至少三个氧原子在台阶上的协同稳定构型。在这里，两个氧原子将第三个氧原子招募到附近的结合位点，从而产生比孤立氧原子活性更强的活性结构。因此，钯上的氢氧化为如何在工作催化剂上增强反应性提供了一个清楚的例子。
▲ abstract：
atomic-scale structures that account for the acceleration of reactivity by heterogeneous catalysts often form only under reaction conditions of high temperatures and pressures, making them impossible to observe with low-temperature, ultra-high-vacuum methods. we present velocity-resolved kinetics measurements for catalytic hydrogen oxidation on palladium over a wide range of surface concentrations and at high temperatures. the rates exhibit a complex dependence on oxygen coverage and step density, which can be quantitatively explained by a density functional and transition-state theory–based kinetic model involving a cooperatively stabilized configuration of at least three oxygen atoms at steps. here, two oxygen atoms recruit a third oxygen atom to a nearby binding site to produce an active configuration that is far more reactive than isolated oxygen atoms. thus, hydrogen oxidation on palladium provides a clear example of how reactivity can be enhanced on a working catalyst.
物理学physics
right dipolar excitons in twisted black phosphorus homostructures
扭曲黑磷同质结构中的亮偶极激子
▲ 作者：shenyang huang, boyang yu, yixuan ma, chenghao pan, junwei ma, yuxuan zhou, yaozhenghang ma, ke yang, hua wu, and hugen yan
▲链接：
https://www.science.org/doi/10.1126/science.adq2977
▲摘要：
明亮的偶极激子含有电偶极子，具有较高的振子强度，是研究量子现象的理想平台。它们通常依靠两个量子阱或两层之间的载流子隧道与非偶极激子杂化以获得振子强度。研究者发现了一种新型的明亮红外偶极激子，通过堆叠90°扭曲的黑磷结构。
这些激子固有的重建带结构表现出高振子强度。最重要的是，它们继承了黑磷线性极化，这使得光偏振可以用来选择偶极子方向。此外，偶极矩和共振能量可以通过黑磷的厚度进行广泛的调谐。研究结果为探索可调谐相关偶极激子提供了一个有用的平台。
▲ abstract：
bright dipolar excitons, which contain electrical dipoles and have high oscillator strength, are an ideal platform for studying correlated quantum phenomena. they usually rely on carrier tunneling between two quantum wells or two layers to hybridize with nondipolar excitons to gain oscillator strength. in this work, we uncovered a new type of bright infrared dipolar exciton by stacking 90°-twisted black phosphorus (bp) structures. these excitons, inherent to the reconstructed band structure, exhibit high oscillator strength. most importantly, they inherit the linear polarization from bp, which allows light polarization to be used to select the dipole direction. moreover, the dipole moment and resonance energy can be widely tuned by the thickness of the bp. our results demonstrate a useful platform for exploring tunable correlated dipolar excitons.
a self-regenerative heat pump based on a dual-functional relaxor ferroelectric polymer
基于双功能弛豫铁电聚合物的自蓄热式热泵
▲ 作者：hanxiang wu, yuan zhu, wenzhong yan, siyu zhang, william budiman, kede liu, jianghan wu, yuan meng, xun zhao, and qibing pei
▲链接：
https://www.science.org/doi/10.1126/science.adr2268
▲摘要：
电热材料可以通过由电场引发的相变来泵送热量。然而，设计保持大温差的设备可能具有挑战性。
wu等人使用铁电聚合物层设计了一种热泵，这种聚合物在电场作用下也会改变形状。几个聚合物薄膜堆叠的级联提供有效的热传递，达到14 k的温差。这种冷却不需要流体或其他增加系统复杂性的策略。
▲ abstract：
electrocaloric materials can pump heat through a phase transition triggered by an electric field. however, designing devices that maintain a large temperature difference can be challenging. wu et al. designed a heat pump using layers of a ferroelectric polymer that also changes shape under an electric field. a cascade of several polymer film stacks provides efficient thermal transfer, reaching a temperature differential of 14 k. this cooling is accomplished without needing fluids or other strategies that increase the complexity of the system.
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