Science, 12 AUG 2022, VOL 377, ISSUE 6607
《科学》2022年8月12日，第377卷，6607期
物理学Physics
Dynamics of active liquid interfaces
活性液体界面动力学
▲ 作者：RAYMOND ADKINSITAMAR KOLVIN, ZHIHONG YOU, SVEN WITTHAUS, M. CRISTINA MARCHETTI AND ZVONIMIR DOGIC
▲ 链接：
https://www.science.org/doi/10.1126/science.abo5423
▲ 摘要：
不相容的液体，如油和水，会以较低的界面张力相分离。作者研究了将主动向列相与被动各向同性相分离的一维界面的动力学。他们发现了波动界面的丰富行为，在这种界面中，相分离流体可以形成活性乳剂，而不会变浓，液滴会自发形成。
宏观界面还可以显示具有特征波数和波速的波的传播。此外，其中一种流体的活动，其中能量的添加驱动了该流体的顺序，能够修改润湿转变。作者还观察到固体表面的主动润湿，即与表面平行的主动伸展应力驱动流体逆重力爬上固体壁。
▲ Abstract：
Incompatible liquids such as oil and water will phase separate with low interfacial tension. Adkins et al. investigated the dynamics of a one-dimensional interface separating an active nematic phase with a passive isotropic phase. They found a rich behavior of fluctuating interfaces in which the phase-separating fluids could form active emulsions that did not coarsen and in which droplets formed spontaneously. Macroscopic interfaces can also displayed propagating waves with a characteristic wave number and speed. Furthermore, the activity of one of the fluids, in which the addition of energy drove the ordering of that fluid, was able to modify the wetting transitions. The authors also observed active wetting of a solid surface whereby active extensile stresses parallel to the surface drove the fluid to climb a solid wall against gravity.
Proton-coupled energy transfer in molecular triads
分子三联体中的质子耦合能量转移
▲ 作者：BELINDA PETTERSSON RIMGARD, ZHEN TAO, GIOVANNY A. PARADA, LAURA F. COTTERSHARON HAMMES-SCHIFFER, JAMES M. MAYER, AND LEIF HAMMARSTROM
▲ 链接：
https://www.science.org/doi/10.1126/science.abq5173
▲ 摘要：
质子耦合电子转移（PCET）反应因其在生物学中各种能量转换过程中的重要作用而引起广泛关注。作者报告了另一种叫作质子耦合能量转移（PCEnT）的机制，其中质子转移与电子激发能量转移相耦合。
在低温条件下，当PCET受到热力学阻碍时，作者通过实验检测了一系列蒽-酚-吡啶三聚体的激发态行为。理论计算表明，观察到的PCEnT是一个非绝热的单重态-单重态能量转移耦合到质子隧穿，不同于PCET，它发生在施主和受主之间且没有电荷转移。
PCEnT在光激活化学、光子材料和光生物学方面具有潜在的重要意义，但在自然系统中尚未被确定。
▲ Abstract：
Proton-coupled electron transfer (PCET) reactions have generated considerable interest because of their essential role in various energy conversion processes in biology. Pettersson Rimgard et al. report another type of mechanism denoted as proton-coupled energy transfer (PCEnT), in which proton transfer is coupled to electronic excitation energy transfer. PCEnT was experimentally detected when analyzing the excited state behavior for a series of anthracene-phenol-pyridine trimers in low-temperature conditions, where PCET is thermodynamically hindered. Theoretical calculations showed that the observed PCEnT is a non-adiabatic singlet-singlet energy transfer coupled to proton tunneling, which, unlike PCET, occurs with no charge transfer between donor and acceptor. PCEnT is potentially important for light-activated chemistry, photonic materials, and photobiology, but it has yet to be identified for natural systems.
Cavity-mediated electron-photon pairs
腔介导的电子-光子对
▲ 作者：ARMIN FEIST, GUANHAO HUANG, GERMAINE AREND, YUJIA YANG, HUGO LOURENÇO-MARTINS, CLAUS ROPERS, etc.
▲ 链接：
https://www.science.org/doi/10.1126/science.abo5037
▲ 摘要：
电子束与空腔和共振结构的相互作用代表了产生电磁辐射的通用方案。Feist等人在基于光子芯片的微谐振腔中制造了自由电子与真空腔场相匹配的相互作用结构。
当电子通过谐振腔附近时，它们与真空场之间的耦合导致光子在腔内自发产生。由于电子-光子对是相关的，它们应该是自由电子量子光学发展的一个有用的来源，提供增强的成像和传感能力。
▲ Abstract：
The interaction of electron beams with cavities and resonant structures represents a universal scheme for generating electromagnetic radiation. Feist et al. fabricated structures with phase-matched interactions between free electrons and the vacuum cavity field of a photonic chip-based microresonator. As the electrons passed near the resonator, coupling between them and the vacuum field resulted in the spontaneous generation of photons within the cavity. Because the electron-photon pairs are correlated, they should be a useful source for the development of free-electron quantum optics providing enhanced imaging and sensing capabilities.
化学Chemistry
Electron in a cube: Synthesis and characterization of perfluorocubane as an electron acceptor
作为电子受体的全氟苯的合成和表征
▲ 作者：MASAFUMI SUGIYAMA, MIDORI AKIYAM, YUKI YONEZAWAKENJI, XKYOKO NOZAKI, AND TAKASHI OKAZOE, etc.
▲ 链接：
https://www.science.org/doi/10.1126/science.abn8699
▲ 摘要：
近60年前，合成立方体形状的碳氢化合物是化学上的一个重大事件，因为这种化合物十分美丽、高度对称，有着明显非自然的几何键形状。
作者现在已经合成了一种立方体衍生物，并在结构上对其进行了表征，其中每个顶点的氢原子都被氟取代。与理论预测一致，低温电子自旋共振光谱表明，分子在还原时集中内在化一个电子。
▲ Abstract：
The synthesis of a cube-shaped hydrocarbon nearly 60 years ago was a major event in chemistry, both because of the compound’s beautiful, high symmetry and its distinctly unnatural bonding geometry. Sugiyama et al. have now synthesized and structurally characterized a cubane derivative in which the hydrogen atoms at each vertex are replaced by fluorines. Consistent with theoretical predictions, low-temperature electron spin resonance spectroscopy suggests that the molecule centrally internalizes an electron upon reduction.
Controlled tough bioadhesion mediated by ultrasound
超声介导的可控坚韧生物黏附
▲ 作者：ZHENWEI MA, CLAIRE BOURQUARD, QIMAN GAO, SHUAIBING JIANG, TRISTAN DE IURE-GRIMMEL, RAN HUO, XUAN LI, ZIXIN HE, ZHEN YANG, JIANYU LI
▲ 链接：
https://www.science.org/doi/10.1126/science.abn8699
▲ 摘要：
组织黏接剂在临时或永久组织修复、伤口管理和可穿戴电子设备的附着中都能发挥作用。然而，使用时，需要调整黏附强度以确保可逆性并保持渗透性，这可能是一个挑战。
作者设计了由聚丙烯酰胺（N异丙基丙烯酰胺)与海藻酸盐结合制成的水凝胶，使用含有壳聚糖、明胶或纤维素纳米晶体纳米颗粒的溶液进行填充。超声的应用引起空化，将引物分子推入组织。
锚钉的机械联锁最终导致水凝胶和组织之间不需要化学结合的强黏附。在猪、鼠皮肤上按需剥离可增强黏附性能和界面疲劳抗力。
▲ Abstract：
Tissue adhesives play a role in temporary or permanent tissue repair, wound management, and the attachment of wearable electronics. However, it can be challenging to tailor the adhesive strength to ensure reversibility when desired and to maintain permeability. Ma et al. designed hydrogels made of polyacrylamide or poly(N-isopropylacrylamide) combined with alginate that are primed using a solution containing nanoparticles of chitosan, gelatin, or cellulose nanocrystals. The application of ultrasound causes cavitation that pushes the primer molecules into the tissue. The mechanical interlocking of the anchors eventually results in strong adhesion between hydrogel and tissue without the need for chemical bonding. Tests on porcine or rat skin showed enhanced adhesion energy and interfacial fatigue resistance with on-demand detachment.
生物学Biology
Individual tracking reveals long-distance flight-path control in a nocturnally migrating moth
个体追踪揭示夜间迁徙飞蛾的长距离飞行路径控制
▲ 作者：MYLES H. M. MENZ, MARTINA SCACCO, HANS-MARTIN BURKI-SPYCHER, HANNAH J. WILLIAMS, DON R. REYNOLDS, JASON W. CHAPMAN, AND MARTIN WIKELSKI
▲ 链接：
https://www.science.org/doi/10.1126/science.abn1663
▲ 摘要：
人们对于迁徙物种长距离跋涉如何导航仍然知之甚少。对无脊椎动物来说尤其如此，相关监测具有挑战性。然而，新技术带来了极其轻的、安装在动物身上的标签，为这一领域的研究开辟了新的途径作者使用这种标签来跟踪在欧洲和撒哈拉以南非洲之间迁徙的一种鹰蛾的飞行。
他们发现，即使面对破坏性的风和高山，飞蛾也能纠正自己的特定路线。这项研究表明，飞蛾不仅仅是被动地朝正确的方向移动，而是根据内部地图或指南针主动导航。
▲ Abstract：
We still know little about how many migrating species navigate across vast distances. This is especially true for invertebrates, which are challenging to monitor. However, new technologies leading to extremely light, animal-mounted tags are opening up new research avenues in this area. Menz et al. used such tags to track the flight of death’s-head hawkmoths that migrate between Europe and sub-Saharan Africa. They found that the moths were able to correct to their specific course even in the face of disruptive winds and high mountains. This work suggests that the moths are not merely passively moving in the right direction, but instead actively navigating based on an internal map or compass.
转自：科学网
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