物理学Physics

▲ 作者：ANDREAS BOES, LIN CHANG, CARSTEN LANGROCK, MENGJIE YU, MIAN ZHANG, QIANG LIN, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.abj4396

▲ 摘要：

铌酸锂（LN）于70年前首次合成，已广泛应用于从通信到量子光学的各种领域。这些大量商业应用为建立高质量LN晶体和晶片的成熟制造和加工行业提供了经济手段。由于LN能够产生和操纵从微波到紫外频率的广谱电磁波，其商业产品的突破性科学演示已经实现。

研究组对LN作为一种光学材料的历史、其不同的光子平台、工程概念、光谱范围和基本应用进行了高层次回顾，并对LN的未来进行了展望。

▲ Abstract：

Lithium niobate (LN), first synthesized 70 years ago, has been widely used in diverse applications ranging from communications to quantum optics. These high-volume commercial applications have provided the economic means to establish a mature manufacturing and processing industry for high-quality LN crystals and wafers. Breakthrough science demonstrations to commercial products have been achieved owing to the ability of LN to generate and manipulate electromagnetic waves across a broad spectrum, from microwave to ultraviolet frequencies. Here, we provide a high-level Review of the history of LN as an optical material, its different photonic platforms, engineering concepts, spectral coverage, and essential applications before providing an outlook for the future of LN.

▲ 作者：DAVID A. B. MILLER

▲ 链接：

https://www.science.org/doi/10.1126/science.ade3395

▲ 摘要：

这项研究表明了光学系统需要厚度以及宽度或面积的原因与时机。波衍射解释了在显微镜和照相机中，为了达到一定的分辨率或像素数，对透镜或光圈的面积或直径的基本需求。

这项工作表明，如果人们知道光学器件的用途，甚至在设计之前，就可以推导出所需的最小厚度。该极限来自于衍射和一个称为重叠非定域性C概念的结合，这个概念可严格从器件用途的数学描述中推导出来。C表示不同输出区域的输入区域有多少重叠。

这一限制广泛适用于光学器件，从相机到超构表面，以及一般的波系统。

▲ Abstract：

This study shows why and when optical systems need thickness as well as width or area. Wave diffraction explains the fundamental need for area or diameter of a lens or aperture to achieve some resolution or number of pixels in microscopes and cameras. This work demonstrates that if we know what the optics is to do, even before design, we can also deduce the minimum required thickness. This limit comes from diffraction combined with a concept called overlapping nonlocality C that can be deduced rigorously from just the mathematical description of what the device is to do. C expresses how much the input regions for different output regions overlap. This limit applies broadly to optics, from cameras to metasurfaces, and to wave systems generally.

材料科学Materials Science

▲ 作者：ZHONGSHU REN, LIN GAO, SAMUEL J. CLARK, KAMEL FEZZAA, PAVEL SHEVCHENKO, ANN CHOI, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.add4667

▲ 摘要：

孔隙性缺陷是目前阻碍基于激光的金属增材制造技术广泛采用的主要因素。当因过量激光能量输入而形成不稳定的蒸汽低压区（锁孔）时，就会出现一种常见的孔隙。

通过同时进行高速同步x射线成像和热成像，再联合多物理模拟，研究组发现了Ti-6Al-4V激光粉末床熔融中两种类型的锁孔振荡。

利用机器学习，研究组扩展了这一理解，并开发了一种检测随机锁孔孔隙度生成事件的方法，该方法具有亚毫秒级时间分辨率和近乎完美的预测率。通过Operando x射线成像实现的高度准确的数据标记，研究组展示了一条在商业系统中采用该方法的简便而实用的途径。

▲ Abstract：

Porosity defects are currently a major factor that hinders the widespread adoption of laser-based metal additive manufacturing technologies. One common porosity occurs when an unstable vapor depression zone (keyhole) forms because of excess laser energy input. With simultaneous high-speed synchrotron x-ray imaging and thermal imaging, coupled with multiphysics simulations, we discovered two types of keyhole oscillation in laser powder bed fusion of Ti-6Al-4V. Amplifying this understanding with machine learning, we developed an approach for detecting the stochastic keyhole porosity generation events with submillisecond temporal resolution and near-perfect prediction rate. The highly accurate data labeling enabled by operando x-ray imaging allowed us to demonstrate a facile and practical way to adopt our approach in commercial systems.

地球科学Earth Science

▲ 作者：DAVID R. ROUNCE, REGINE HOCK, FABIEN MAUSSION, ROMAIN HUGONNET, WILLIAM KOCHTITZKY, MATTHIAS HUSS, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.abo1324

▲ 摘要：

冰川质量损失影响海平面上升、水资源和自然灾害。研究组提出了全球冰川预测（不包括冰盖），以每个冰川的数据校准共享社会经济路径。

在全球温度变化情景下，相对于2015年，到2100年时预计冰川质量将损失26±6%（+1.5℃）至41±11%（+4℃）。这相当于海平面上升90±26~154±44毫米，将导致49±9~83±7%的冰川消失。

质量损失与温度升高呈线性相关，因此温度增加的减缓可降低质量损失。根据第26次缔约方大会（COP26）的气候承诺，预计到2100年，全球平均气温将增加2.7℃，这将导致海平面上升115±40毫米，并在大多数中纬度地区造成广泛的冰川消融。

▲ Abstract：

Glacier mass loss affects sea level rise, water resources, and natural hazards. We present global glacier projections, excluding the ice sheets, for shared socioeconomic pathways calibrated with data for each glacier. Glaciers are projected to lose 26 ± 6% (+1.5°C) to 41 ± 11% (+4°C) of their mass by 2100, relative to 2015, for global temperature change scenarios. This corresponds to 90 ± 26 to 154 ± 44 millimeters sea level equivalent and will cause 49 ± 9 to 83 ± 7% of glaciers to disappear. Mass loss is linearly related to temperature increase and thus reductions in temperature increase reduce mass loss. Based on climate pledges from the Conference of the Parties (COP26), global mean temperature is projected to increase by +2.7°C, which would lead to a sea level contribution of 115 ± 40 millimeters and cause widespread deglaciation in most mid-latitude regions by 2100.

公共卫生Public Health

▲ 作者：QI PENG, YUFENG XIE, LU KUAI, HAN WANG, JIANXUN QI, GEORGE F. GAO, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.ade6360

▲ 摘要：

世界卫生组织于2022年7月宣布猴痘为国际关注的突发公共卫生事件，迫切需要采取预防和治疗措施。猴痘病毒（MPXV）具有自己的DNA聚合酶F8，以及加工辅因子A22和E4，构成用于基因组复制的聚合酶全酶。

研究组使用冷冻电子显微镜在~2.8埃的全局分辨率下确定了与DNA复合的全酶结构。该全酶的结构表明病毒DNA复制具有一种“向前滑动钳”的加工机制。

MPXV聚合酶的DNA结合模式与来自不同物种的其他B族DNA聚合酶相似。这些发现揭示了MPXV基因组复制的机制，并有望指导抗痘病毒药物的开发。

▲ Abstract：

The World Health Organization declared mpox (or monkeypox) a public health emergency of international concern in July 2022, and prophylactic and therapeutic measures are in urgent need. The monkeypox virus (MPXV) has its own DNA polymerase F8, together with the processive cofactors A22 and E4, constituting the polymerase holoenzyme for genome replication. Here, we determined the holoenzyme structure in complex with DNA using cryo–electron microscopy at the global resolution of ~2.8 angstroms. The holoenzyme possesses an architecture that suggests a “forward sliding clamp” processivity mechanism for viral DNA replication. MPXV polymerase has a DNA binding mode similar to that of other B-family DNA polymerases from different species. These findings reveal the mechanism of the MPXV genome replication and may guide the development of anti-poxvirus drugs.

免疫学Immunology

▲ 作者：MASAYUKI HATA, ELISABETH M. M. A. ANDRIESSEN, MAKI HATA, ROBERTO DIAZ-MARIN, FRÉDÉRIK FOURNIER, SERGIO CRESPO-GARCIA, ET AL.

▲ 链接：

https://www.science.org/doi/10.1126/science.abj8894

▲ 摘要：

年龄相关性黄斑变性是一种常见的神经炎症性疾病，也是因遗传和环境因素（如肥胖）导致失明的主要原因。在老年性疾病中，可改变的因素可在整个生命周期中复合。

研究组报道，早年饮食引起的肥胖会触发先天免疫系统的持续重编程，在代谢异常正常化后仍会持续很长时间。硬脂酸通过Toll样受体4（TLR4）起作用，足以重塑染色质景观，并选择性地增强活化蛋白-1（AP-1）结合位点的可及性。

髓系细胞表现出较少的氧化磷酸化并转向糖酵解，最终导致促炎细胞因子转录、病理性视网膜血管生成加重，以及与视觉功能丧失相关的神经元变性。因此，既往肥胖史会重编程单核吞噬细胞，并易发生神经炎症。

▲ Abstract：

Age-related macular degeneration is a prevalent neuroinflammatory condition and a major cause of blindness driven by genetic and environmental factors such as obesity. In diseases of aging, modifiable factors can be compounded over the life span. We report that diet-induced obesity earlier in life triggers persistent reprogramming of the innate immune system, lasting long after normalization of metabolic abnormalities. Stearic acid, acting through Toll-like receptor 4 (TLR4), is sufficient to remodel chromatin landscapes and selectively enhance accessibility at binding sites for activator protein-1 (AP-1). Myeloid cells show less oxidative phosphorylation and shift to glycolysis, ultimately leading to proinflammatory cytokine transcription, aggravation of pathological retinal angiogenesis, and neuronal degeneration associated with loss of visual function. Thus, a past history of obesity reprograms mononuclear phagocytes and predisposes to neuroinflammation.