Science, 2 JUN 2023, VOL 380, ISSUE 6648
《科学》2023年6月2日，第380卷，6648期
材料科学Materials Science
Autonomous alignment and healing in multilayer soft electronics using immiscible dynamic polymers
采用不相容动态聚合物的多层柔性电子器件的自主排列和修复
▲ 作者：CHRISTOPHER B. COOPER, SAMUEL E. ROOT, LUKAS MICHALEK, SHUAI WU, JIAN-CHENG LAI, MUHAMMAD KHATIB, et al.
▲ 链接：
https://www.science.org/doi/10.1126/science.adh0619
▲ 摘要：
自我修复的柔性电子和机器人设备可以像人的皮肤一样，从损伤中自动恢复。虽然目前设备对所有功能层都使用单一类型的动态聚合物涂覆以确保强层间粘附，但这种方法需要手动层对齐。
在这项研究中，研究组使用了两种动态聚合物，其具有不相容的骨架，但有着相同的动态键以保持层间粘附，同时在修复过程中实现自主重新排列。这些动态聚合物表现出宽度可调的弱互穿和粘合界面。
当多层聚合物膜在损伤后错位时，这些结构在修复过程中自动重新排列，以最大限度地减少界面自由能。研究组制造了具有导电、介电和磁性颗粒的设备，这些设备在损坏后可以自愈，从而实现薄膜压力传感器、磁性组装软机器人和水下电路组装。
▲ Abstract：
Self-healing soft electronic and robotic devices can, like human skin, recover autonomously from damage. While current devices use a single type of dynamic polymer for all functional layers to ensure strong interlayer adhesion, this approach requires manual layer alignment. In this study, we used two dynamic polymers, which have immiscible backbones but identical dynamic bonds, to maintain interlayer adhesion while enabling autonomous realignment during healing. These dynamic polymers exhibit a weakly interpenetrating and adhesive interface, whose width is tunable. When multilayered polymer films are misaligned after damage, these structures autonomously realign during healing to minimize interfacial free energy. We fabricated devices with conductive, dielectric, and magnetic particles that functionally heal after damage, enabling thin-film pressure sensors, magnetically assembled soft robots, and underwater circuit assembly.
A sinterless, low-temperature route to 3D print nanoscale optical-grade glass
3D打印纳米级光学玻璃的无烧结低温路径
▲ 作者：J. BAUER , C. CROOK, AND T. BALDACCHINI
▲ 链接：
https://www.science.org/doi/10.1126/science.abq3037
▲ 摘要：
二氧化硅玻璃的三维（3D）打印主要依靠传统的颗粒烧结技术。在纳米尺度上，这限制了其在微系统技术中的应用，从而阻碍了技术突破。
研究组介绍了用多面体低聚倍半硅氧烷（POSS）树脂制备的自由形态熔融二氧化硅纳米结构的无烧结、双光子聚合3D打印。与颗粒负载的牺牲粘合剂相反，该POSS树脂本身构成连续的硅氧分子网络，仅在650℃下就可形成透明的熔融二氧化硅。
该温度比将离散二氧化硅颗粒熔融为连续体的烧结温度低500℃，这使得二氧化硅3D打印低于基本微系统材料的熔点。同时，研究组实现了四倍分辨率增强，使可见光纳米光子学成为可能。
通过展示优异的光学质量、机械弹性、易于加工和可覆盖的尺寸规模，该材料为无机固体的微纳米3D打印设定了基准。
▲ Abstract：
Three-dimensional (3D) printing of silica glass is dominated by techniques that rely on traditional particle sintering. At the nanoscale, this limits their adoption within microsystem technology, which prevents technological breakthroughs. We introduce the sinterless, two-photon polymerization 3D printing of free-form fused silica nanostructures from a polyhedral oligomeric silsesquioxane (POSS) resin. Contrary to particle-loaded sacrificial binders, our POSS resin itself constitutes a continuous silicon-oxygen molecular network that forms transparent fused silica at only 650°C. This temperature is 500°C lower than the sintering temperatures for fusing discrete silica particles to a continuum, which brings silica 3D printing below the melting points of essential microsystem materials. Simultaneously, we achieve a fourfold resolution enhancement, which enables visible light nanophotonics. By demonstrating excellent optical quality, mechanical resilience, ease of processing, and coverable size scale, our material sets a benchmark for micro– and nano–3D printing of inorganic solids.
化学Chemistry
Tracking C–H activation with orbital resolution
以轨道分辨率跟踪C-H活化
▲ 作者：RAPHAEL M. JAY, AMBAR BANERJEE, TORSTEN LEITNER, RU-PAN WANG, JESSICA HARICH, ROBERT STEFANUIK, ET AL.
▲ 链接：
https://www.science.org/doi/10.1126/science.adf8042
▲ 摘要：
过渡金属对碳-氢（C-H）键的反应性取决于金属中心电子给予和回收的相互作用。以可控方式操纵这种反应性很困难，因为设想的金属-烷烃电荷转移相互作用在实验实现上颇具挑战性。
利用时间分辨X射线光谱，研究组跟踪了环戊二烯基-铑-羰基配合物在辛烷C-H活化过程中的电荷转移相互作用，在飞秒到纳秒时间尺度的数据中发现了氧化态以及价轨道能和特征的变化。
X射线光谱特征反映了烷烃对金属的贡献如何决定金属-烷烃配合物的稳定性，以及金属对烷烃的反贡献如何通过氧化加成促进C-H键的断裂。在轨道水平上剖析电荷转移相互作用的能力，将助力操纵过渡金属的C-H反应性。
▲ Abstract：
Transition metal reactivity toward carbon–hydrogen (C–H) bonds hinges on the interplay of electron donation and withdrawal at the metal center. Manipulating this reactivity in a controlled way is difficult because the hypothesized metal-alkane charge-transfer interactions are challenging to access experimentally. Using time-resolved x-ray spectroscopy, we track the charge-transfer interactions during C–H activation of octane by a cyclopentadienyl rhodium carbonyl complex. Changes in oxidation state as well as valence-orbital energies and character emerge in the data on a femtosecond to nanosecond timescale. The x-ray spectroscopic signatures reflect how alkane-to-metal donation determines metal-alkane complex stability and how metal-to-alkane back-donation facilitates C–H bond cleavage by oxidative addition. The ability to dissect charge-transfer interactions on an orbital level provides opportunities for manipulating C–H reactivity at transition metals.
生物传感Biosensing
Miniature magneto-mechanical resonators for wireless tracking and sensing
用于无线跟踪和传感的微型磁机械共振器
▲ 作者：BERNHARD GLEICH, INGO SCHMALE, TIM NIELSEN, AND JÜRGEN RAHMER
▲ 链接：
https://www.science.org/doi/10.1126/science.adf5451
▲ 摘要：
传感器微型化通过原位提供过程反馈，实现了微创医疗手术或患者监测等应用。理想情况下，微型传感器应该是无线、廉价的，并允许通过可负担的检测系统在足够距离上进行远程检测。
研究组从理论上分析了无线传感器的信号强度，并推导出体积小于1立方毫米的高信号共振磁机械传感器的简单设计方案。作为示例，研究组演示了在无屏蔽环境中实时跟踪飞行蜜蜂的位置和姿态、导航活检针、跟踪自由流动标记物，以及感知压力和温度。
研究组实现的传感器尺寸、测量精度和约25厘米的工作空间，为医疗和非医疗应用提供了低成本无线跟踪和传感平台的潜力。
▲ Abstract：
Sensor miniaturization enables applications such as minimally invasive medical procedures or patient monitoring by providing process feedback in situ. Ideally, miniature sensors should be wireless, inexpensive, and allow for remote detection over sufficient distance by an affordable detection system. We analyze the signal strength of wireless sensors theoretically and derive a simple design of high-signal resonant magneto-mechanical sensors featuring volumes below 1 cubic millimeter. As examples, we demonstrate real-time tracking of position and attitude of a flying bee, navigation of a biopsy needle, tracking of a free-flowing marker, and sensing of pressure and temperature, all in unshielded environments. The achieved sensor size, measurement accuracy, and workspace of ~25 centimeters show the potential for a low-cost wireless tracking and sensing platform for medical and nonmedical applications.
人类学Anthropology
Body-based units of measure in cultural evolution
文化进化中基于身体的度量单位
▲ 作者：ROOPE O. KAARONEN, MIKAEL A. MANNINEN, AND JUSSI T. ERONEN
▲ 链接：
https://www.science.org/doi/10.1126/science.adf1936
▲ 摘要：
度量系统是文化和技术进化的重要驱动力。然而，人们仍未充分理解度量的演变。许多早期的标准化计量系统都从基于身体的度量单位演变而来，比如肘和英寻，但人们很少探究如何或为何使用基于身体的度量。
研究组记录了186种文化中基于身体的计量单位，证明了基于身体的度量如何在世界各地的文化中普遍存在。他们描述了这些单位所使用的文化和技术领域，并认为基于身体的度量单位曾有并且可能仍然具有超越标准化系统的优势，例如在人体工程学技术的设计领域。
这有助于解释在第一个标准化度量系统出现几个世纪后，基于身体的度量仍持续存在。
▲ Abstract：
Measurement systems are important drivers of cultural and technological evolution. However, the evolution of measurement is still insufficiently understood. Many early standardized measurement systems evolved from body-based units of measure, such as the cubit and fathom, but researchers have rarely studied how or why body-based measurement has been used. We documented body-based units of measure in 186 cultures, illustrating how body-based measurement is an activity common to cultures around the world. Here, we describe the cultural and technological domains these units are used in. We argue that body-based units have had, and may still have, advantages over standardized systems, such as in the design of ergonomic technologies. This helps explain the persistence of body-based measurement centuries after the first standardized measurement systems emerged.
化学Chemistry
Heart-brain connections: Phenotypic and genetic insights from magnetic resonance images
心脑联系：磁共振图像的表型和遗传学见解
▲ 作者：BINGXIN ZHAO, TENGFEI LI, ZIRUI FAN, YUE YANG, JUAN SHU, XIAOCHEN YANG, ET AL.
▲ 链接：
https://www.science.org/doi/10.1126/science.abn6598
▲ 摘要：
心血管健康以复杂的方式与认知和心理健康相互作用，但人们对心脑系统的表型和遗传联系知之甚少。
研究组使用来自4万多名受试者的多器官磁共振成像（MRI）数据量化了心脑联系。心脏MRI特征显示了许多与脑灰质形态计量学、白质微观结构和功能网络的关联模式。
研究组确定了80个与心脏MRI特征相关的基因组基因座（P < 6.09×10−10），这些基因座与心血管和脑部疾病有共同的遗传影响。还观察到心脏MRI特征与大脑相关特征和疾病之间存在遗传相关性。
孟德尔随机化研究表明，心脏疾病可能会导致脑部疾病。该研究结果通过揭示心脑联系和共同遗传影响，推进了人类健康的多器官视角。
▲ Abstract：
Cardiovascular health interacts with cognitive and mental health in complex ways, yet little is known about the phenotypic and genetic links of heart-brain systems. We quantified heart-brain connections using multiorgan magnetic resonance imaging (MRI) data from more than 40,000 subjects. Heart MRI traits displayed numerous association patterns with brain gray matter morphometry, white matter microstructure, and functional networks. We identified 80 associated genomic loci (P < 6.09 × 10−10) for heart MRI traits, which shared genetic influences with cardiovascular and brain diseases. Genetic correlations were observed between heart MRI traits and brain-related traits and disorders. Mendelian randomization suggests that heart conditions may causally contribute to brain disorders. Our results advance a multiorgan perspective on human health by revealing heart-brain connections and shared genetic influences.
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