科研
科研
编译|冯维维
Science, 15 November 2024, Volume 386, Issue 6723
《科学》2024年11月15日，第386卷，6723期
化学Chemistry
Detection of interstellar 1-cyanopyrene: A four-ring polycyclic aromatic hydrocarbon
星际四环多环芳烃1—氰芘的检测
▲ 作者：GABI WENZEL, ILSA R. COOKE, P. BRYAN CHANGALA, EDWIN A. BERGIN, SHUO ZHANG, ANDREW M. BURKHARDT, ALEX N. BYRNE, STEVEN B. CHARNLEY, MARTIN A. CORDINER, AND BRETT A. MCGUIRE
▲链接：
https://www.science.org/doi/10.1126/science.adq6391
▲摘要：
多环芳烃（PAHs）是含有相邻芳环的有机分子。红外发射波段表明，多环芳烃在太空中是丰富的，但在星际介质中只检测到少数特定的多环芳烃。研究者利用绿岸望远镜对致密星云TMC—1进行射电观测，发现了1—氰芘，一种四环多环芳烃芘相关的氰基取代衍生物。
他们测得的1—氰芘柱密度约为1.52×1012cm-2，由此估计芘在TMC-1中含有高达0.1%的碳。这种丰度表明星际多环芳烃化学有利于芘的产生。研究者认为，一些提供给年轻行星系统的碳是由起源于冷分子云的多环芳烃携带的。
▲ Abstract：
Polycyclic aromatic hydrocarbons (PAHs) are organic molecules containing adjacent aromatic rings. Infrared emission bands show that PAHs are abundant in space, but only a few specific PAHs have been detected in the interstellar medium. We detected 1-cyanopyrene, a cyano-substituted derivative of the related four-ring PAH pyrene, in radio observations of the dense cloud TMC-1, using the Green Bank Telescope. The measured column density of 1-cyanopyrene is ~ 1.52×1012cm-2, from which we estimate that pyrene contains up to 0.1% of the carbon in TMC-1. This abundance indicates that interstellar PAH chemistry favors the production of pyrene. We suggest that some of the carbon supplied to young planetary systems is carried by PAHs that originate in cold molecular clouds.
Synchronous recognition of amines in oxidative carbonylation toward unsymmetrical ureas
不对称尿素氧化羰基化过程中胺的同步识别
▲ 作者：JINHUI WANG, SHENGCHUN WANG, ZHIHONG WEI, PENGJIE WANG, YANWEI CAO, YANG HUANG, LIN HE, AND AIWEN LEI
▲链接：
https://www.science.org/doi/10.1126/science.adl0149
▲摘要：
不对称尿素常见于药品和生物活性化合物中。然而，设计策略来选择性地引入两种不同的胺来构建不对称脲仍然是一个挑战。研究者使用同步识别策略，利用自由基和亲核活化来区分仲胺和伯胺。
具体而言，铜催化剂优先将仲胺氧化为自由基，而钴催化剂将伯胺羰基化以产生钴酰胺。这些片段通过协同催化偶联产生具有高选择性的不对称脲，41种生物活性化合物和6种药物的修饰证明了这一点。
▲ Abstract：
Unsymmetrical ureas are commonly found in pharmaceuticals and bioactive compounds. However, devising strategies to introduce two distinct amines selectively in the construction of unsymmetrical ureas remains a challenge. In this work, we use a synchronous recognition strategy that takes advantage of radical and nucleophilic activation to discriminate between secondary and primary amines. Specifically, a copper catalyst preferentially oxidizes secondary amines to radical species, whereas a cobalt catalyst carbonylates primary amines to produce cobalt amides. Coupling these fragments by cooperative catalysis produces unsymmetrical ureas with high selectivity, as showcased by the modification of 41 biologically active compounds and six drugs.
物理学Physics
Subambient daytime radiative cooling of vertical surfaces
垂直表面的白天辐射冷却
▲ 作者：FEI XIE, WEILIANG JIN, J. RYAN NOLEN, HAO PAN, NAIQIN YI, YANG AN, ZHIYU ZHANG, XIANGTONG KONG, FEI ZHU, AND WEI LI
▲链接：
https://www.science.org/doi/10.1126/science.adn2524
▲摘要：
白天亚环境辐射冷却通过向外层空间发射热辐射，使温度被动地低于环境温度，即使在阳光直射下也是如此。这项技术有许多令人兴奋的应用前景。然而，以前的亚环境日间辐射冷却的演示需要直接面向天空的表面，而这些不能应用于在现实场景中无处不在的垂直表面，如建筑物和车辆。
研究者使用分层设计，角度不对称，光谱选择性热发射器演示了峰值阳光下垂直表面的亚环境日间辐射冷却。在每平方米约920瓦的峰值阳光下，他们的发射器达到的温度比环境温度低约2.5°C，与硅聚合物混合辐射冷却器和商用白漆相比，温度分别降低了约4.3°C和8.9°C。
▲ Abstract：
Subambient daytime radiative cooling enables temperatures to passively reach below ambient temperature, even under direct sunlight, by emitting thermal radiation toward outer space. This technology holds promise for numerous exciting applications. However, previous demonstrations of subambient daytime radiative cooling require surfaces that directly face the sky, and these cannot be applied to vertical surfaces that are ubiquitous in real-world scenarios such as buildings and vehicles. Here, we demonstrate subambient daytime radiative cooling of vertical surfaces under peak sunlight using a hierarchically designed, angularly asymmetric, spectrally selective thermal emitter. Under peak sunlight of about 920 watts per square meter, our emitter reaches a temperature that is about 2.5°C below ambient temperature, corresponding to a temperature reduction of about 4.3° and 8.9°C compared with a silica-polymer hybrid radiative cooler and commercial white paint, respectively.
Glaciation of liquid clouds, snowfall, and reduced cloud cover at industrial aerosol hot spots
工业气溶胶热点的冷凝作用
▲ 作者：VELLE TOLL, JORMA RAHU, HANNES KEERNIK, HEIDO TROFIMOV, TANEL VOORMANSIK, PETER MANSHAUSEN, EMMA HUNG, DANIEL MICHELSON, MATTHEW W. CHRISTENSEN, AND NICOLAS BELLOUIN
▲链接：
https://www.science.org/doi/10.1126/science.adl0303
▲摘要：
人为气溶胶冻结过冷云滴的能力仍然存在争议。研究者提供了温度在—10°C和—24°C之间的工业气溶胶热点的过冷液态水云结冰的观测证据。与附近液态水云相比，受冰川影响区域的短波反射率降低了14%，长波辐射增加了4%。云量减少了8%，云光学厚度减少了18%。此外，每天由冰川引起的降雪量达到15毫米。
工业气溶胶热点顺风方向的冰期事件表明，人为气溶胶可能起到冰核粒子的作用。然而，核电站顺风处罕见的冰川事件表明，除气溶胶排放外，其他因素也可能在观测到的冰川事件中起作用。
▲ Abstract：
The ability of anthropogenic aerosols to freeze supercooled cloud droplets remains debated. In this work, we present observational evidence for the glaciation of supercooled liquid-water clouds at industrial aerosol hot spots at temperatures between -10° and -24°C. Compared with the nearby liquid-water clouds, shortwave reflectance was reduced by 14% and longwave radiance was increased by 4% in the glaciation-affected regions. There was an 8% reduction in cloud cover and an 18% reduction in cloud optical thickness. Additionally, daily glaciation-induced snowfall accumulations reached 15 millimeters. Glaciation events downwind of industrial aerosol hot spots indicate that anthropogenic aerosols likely serve as ice-nucleating particles. However, rare glaciation events downwind of nuclear power plants indicate that factors other than aerosol emissions may also play a role in the observed glaciation events.
生态学与地质学Ecology & Geology
Diverse and larger tree islands promote native tree diversity in oil palm landscapes
多样化的更大的树岛促进了油棕景观中原生树木的多样性
▲ 作者：GUSTAVO B. PATERNO , FABIAN BRAMBACH, NATHALY GUERRERO-RAMíREZ, DELPHINE CLARA ZEMP, AIZA F. CANTILLO, NICOLò CAMARRETTA, CARINA C. M. MOURA, OLIVER GAILING, JOHANNES BALLAUFF, AND HOLGER KREFT
▲链接：
https://www.science.org/doi/10.1126/science.ado1629
▲摘要：
在单一栽培为主的景观中，恢复生物多样性是一个优先事项，但有效的恢复策略尚未确定。本研究对油棕景观中52个人工岛木本植物的分类、系统发育和功能多样性进行了被动恢复策略和主动恢复策略的对比研究。大的树岛和较高的初始植物多样性促进了多样性的恢复，尤其是景观水平上的功能多样性。
在局部尺度上，研究结果表明，更大的初始种植多样性会带来更大的本地招募多样性，从而克服了高度修饰景观中自然招募的局限性。建立大型和多样化的树岛对于保护油棕景观中的珍稀、特有和森林相关物种至关重要。
▲ Abstract：
In monoculture-dominated landscapes, recovering biodiversity is a priority, but effective restoration strategies have yet to be identified. In this study, we experimentally tested passive and active restoration strategies to recover taxonomic, phylogenetic, and functional diversity of woody plants within 52 tree islands established in an oil palm landscape. Large tree islands and higher initial planted diversity catalyzed diversity recovery, particularly functional diversity at the landscape level. At the local scale, results demonstrated that greater initial planting diversity begets greater diversity of native recruits, overcoming limitations of natural recruitment in highly modified landscapes. Establishing large and diverse tree islands is crucial for safeguarding rare, endemic, and forest-associated species in oil palm landscapes.
Predictions of groundwater PFAS occurrence at drinking water supply depths in the United States
美国饮用水供应深度地下水中的PFAS预测
▲ 作者：ANDREA K. TOKRANOV, KATHERINE M. RANSOM, LAURA M. BEXFIELD, BRUCE D. LINDSEY, ELISE WATSON, DANIELLE I. DUPUY, PAUL E. STACKELBERG, MIRANDA S. FRAM, STEFAN A. VOSS, AND PAUL M. BRADLEY
▲链接：
https://www.science.org/doi/10.1126/science.ado6638
▲摘要：
全氟烷基和多氟烷基物质（PFAS）俗称“永远的化学品”，对人类健康有不利影响，由于长期和广泛使用，已污染了美国各地的饮用水供应。由于缺乏系统的分析，美国人可能在不知不觉中饮用了含有PFAS的水，特别是在家庭供水中。
研究者提出了一个极端梯度增强模型，用于预测美国邻近地区饮用水供应深处地下水中PFAS的发生。模型结果表明，在美国邻近地区，7100万至9500万人在进行任何处理之前，可能依赖于PFAS浓度可检测的地下水作为饮用水供应。
▲ Abstract：
Per- and polyfluoroalkyl substances (PFAS), known colloquially as “forever chemicals,” have been associated with adverse human health effects and have contaminated drinking water supplies across the United States owing to their long-term and widespread use. People in the United States may unknowingly be drinking water that contains PFAS because of a lack of systematic analysis, particularly in domestic water supplies. We present an extreme gradient–boosting model for predicting the occurrence of PFAS in groundwater at the depths of drinking water supply for the conterminous United States. Our model results indicate that 71 million to 95 million people in the conterminous United States potentially rely on groundwater with detectable concentrations of PFAS for their drinking water supplies before any treatment.
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