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▲ 作者：Patrick Cameron, Baptiste Courme, Chloé Vernière, Raj Pandya, Daniele Faccio & Hugo Defienne

▲ 链接：

http://www.science.org/doi/10.1126/science.adk7825

▲ 摘要：

自适应光学（AO）通过校正光学像差，颠覆了从天文学到显微学等领域的成像。然而，在无标记显微镜中，由于缺乏引导星和需要选择特定于样品和成像过程的优化度量，传统的AO面临局限性。

研究组提出了一种利用纠缠光子之间的相关性来直接校正点扩散函数的AO方法。这种无引导星方法独立于标本和成像方式。他们演示了在存在像差的情况下使用明场成像装置对生物样本进行成像，该装置使用空间纠缠光子对源进行操作。

该方法在校正特定像差方面比传统的AO表现更优，特别是那些涉及大量散焦的像差。该工作改善了无标记显微镜的AO，并有望在量子显微镜的发展中发挥重要作用。

▲ Abstract：

Adaptive optics (AO) has revolutionized imaging in fields from astronomy to microscopy by correcting optical aberrations. In label-free microscopes, however, conventional AO faces limitations because of the absence of a guide star and the need to select an optimization metric specific to the sample and imaging process. Here, we propose an AO approach leveraging correlations between entangled photons to directly correct the point spread function. This guide star–free method is independent of the specimen and imaging modality. We demonstrate the imaging of biological samples in the presence of aberrations using a bright-field imaging setup operating with a source of spatially entangled photon pairs. Our approach performs better than conventional AO in correcting specific aberrations, particularly those involving substantial defocus. Our work improves AO for label-free microscopy and could play a major role in the development of quantum microscopes.

▲ 作者：Qing-Xin Ji, Peng Liu, Warren Jin, Joel Guo, Lue Wu, Zhiquan Yuan, et al.

▲ 链接：

http://www.science.org/doi/10.1126/science.adk9429

▲ 摘要：

高Q微谐振器是光子集成电路中不可或缺的元件，提供了几种可用的工作模式。然而，这些模式不能在制造后重新配置，因其由谐振器的物理几何形状来固定。

在这项工作中，研究组提出了一种莫尔加速色散调谐方法，使微谐振器器件能够在三种模式中的任何一种模式下工作。游标耦合环的电调谐可根据需要使用相同的混合集成设备将操作模式切换为布里渊激光器、亮微梳和暗微梳操作。

研究组演示了电信C波段的布里渊相位匹配和微梳操作。同样，通过使用单泵浦波长，可以切换操作模式。因此，这种通用设计可适用于一系列应用。该器件为集成光子电路带来了灵活的混合模式操作。

▲ Abstract：

High-Q microresonators are indispensable components of photonic integrated circuits and offer several useful operational modes. However, these modes cannot be reconfigured after fabrication because they are fixed by the resonator’s physical geometry. In this work, we propose a Moiré speedup dispersion tuning method that enables a microresonator device to operate in any of three modes. Electrical tuning of Vernier coupled rings switches operating modality to Brillouin laser, bright microcomb, and dark microcomb operation on demand using the same hybrid-integrated device. Brillouin phase matching and microcomb operation across the telecom C-band is demonstrated. Likewise, by using a single-pump wavelength, the operating mode can be switched. As a result, one universal design can be applied across a range of applications. The device brings flexible mixed-mode operation to integrated photonic circuits.

▲ 作者：Jiaqi Liu, Naijia Liu, Yameng Xu, Mingzheng Wu, Haohui Zhang, Yue Wang, et al.

▲ 链接：

http://www.science.org/doi/10.1126/science.adk9880

▲ 摘要：

监测体内平衡是获得病理生理学见解以治疗患者的一个重要方面。准确、及时地评估深层组织内稳态失调通常需要昂贵的成像技术或侵入性活检。

研究组介绍了一种生物可吸收的形状自适应材料结构，可使用常规超声仪实时监测深层组织稳态。通过手术植入或注射器注射，将可生物吸收的小金属盘分布在薄pH响应水凝胶中，可实现基于超声的pH时空变化测量，用于胃肠道手术后吻合口瘘的早期评估，且在恢复期后其生物吸收性避免了再次手术取出。

在小型和大型动物模型中的演示证明了该结构监测小肠、胃和胰腺渗漏的能力。

▲ Abstract：

Monitoring homeostasis is an essential aspect of obtaining pathophysiological insights for treating patients. Accurate, timely assessments of homeostatic dysregulation in deep tissues typically require expensive imaging techniques or invasive biopsies. We introduce a bioresorbable shape-adaptive materials structure that enables real-time monitoring of deep-tissue homeostasis using conventional ultrasound instruments. Collections of small bioresorbable metal disks distributed within thin, pH-responsive hydrogels, deployed by surgical implantation or syringe injection, allow ultrasound-based measurements of spatiotemporal changes in pH for early assessments of anastomotic leaks after gastrointestinal surgeries, and their bioresorption after a recovery period eliminates the need for surgical extraction. Demonstrations in small and large animal models illustrate capabilities in monitoring leakage from the small intestine, the stomach, and the pancreas.

▲ 作者：Shuai Li, Lixin Lu, Swarnendu Bhattacharyya, Carolyn Pearce, Kai Li, Emily T. Nienhuis, et al.

▲ 链接：

http://www.science.org/doi/10.1126/science.adn6059

▲ 摘要：

阿秒-泵浦/阿秒-探针实验长期以来一直被认为是实时观察电子动力学的最直接方法。虽然近红外飞秒和极紫外阿秒脉冲的叠加与理论相结合已取得了很大成功，但真正的阿秒-泵浦/阿秒-探针实验仍然受限。

研究组利用来自X射线自由电子激光器的同步阿秒X射线脉冲对，通过全X射线阿秒瞬态吸收光谱（AX-ATAS）研究了液态水中对价电离的电子响应。

该分析表明，AX-ATAS响应局限于亚飞秒时间尺度，消除了任何氢原子运动，并通过实验证明X射线发射光谱中的1b1分裂与动力学有关，而不是环境液态水中存在两个结构基元的证据。

▲ Abstract：

Attosecond-pump/attosecond-probe experiments have long been sought as the most straightforward method for observing electron dynamics in real time. Although there has been much success with overlapped near-infrared femtosecond and extreme ultraviolet attosecond pulses combined with theory, true attosecond-pump/attosecond-probe experiments have been limited. We used a synchronized attosecond x-ray pulse pair from an x-ray free-electron laser to study the electronic response to valence ionization in liquid water through all x-ray attosecond transient absorption spectroscopy (AX-ATAS). Our analysis showed that the AX-ATAS response is confined to the subfemtosecond timescale, eliminating any hydrogen atom motion and demonstrating experimentally that the 1b1 splitting in the x-ray emission spectrum is related to dynamics and is not evidence of two structural motifs in ambient liquid water.

地球明升体育appEarth Science

▲ 作者：Aaron Bufe, Jeremy K. C. Rugenstein & Niels Hovius

▲ 链接：

http://www.science.org/doi/10.1126/science.adk0957

▲ 摘要：

抬升和侵蚀通过使矿物暴露于明升手机风化作用来调节地质时间尺度上的碳循环。然而，矿物风化的侵蚀敏感性仍然难以量化。

来自不同造山带山溪的溶质明升手机数据集分离出了侵蚀对硅酸盐风化（CO₂汇）和硫化物-碳酸盐耦合物风化（CO₂源）的影响。这些影响的对比侵蚀敏感性在每年约0.07毫米的侵蚀速率下造成最大幅度的二氧化碳减少。

因此，温和抬升速率的地貌增强了地球的无机CO₂汇，而更快速的抬升则减少甚至逆转了CO₂的封存。CO₂减少的“最佳侵蚀”概念调和了关于造山对碳循环影响的相互矛盾的观点，有望实现根据构造变化对地质CO₂通量进行估计。

▲ Abstract：

Uplift and erosion modulate the carbon cycle over geologic timescales by exposing minerals to chemical weathering. However, the erosion sensitivity of mineral weathering remains difficult to quantify. Solute-chemistry datasets from mountain streams in different orogens isolate the impact of erosion on silicate weathering—a carbon dioxide (CO₂) sink—and coupled sulfide and carbonate weathering—a CO₂ source. Contrasting erosion sensitivities of these reactions produce a CO₂-drawdown maximum at erosion rates of ~0.07 millimeters per year. Thus, landscapes with moderate uplift rates bolster Earth’s inorganic CO₂ sink, whereas more rapid uplift decreases or even reverses CO₂ sequestration. This concept of an “erosion optimum” for CO₂ drawdown reconciles conflicting views on the impact of mountain building on the carbon cycle and permits estimates of geologic CO2fluxes dependent upon tectonic changes.