2021-02-26

封面图展示的是2019年飓风多里安对巴哈马群岛造成的洪水破坏情况，美国宇航局喷气推进实验室和新加坡地球天文台利用欧洲Sentinel-1卫星的合成孔径雷达（SAR）数据对其进行了远程评估。通过比较飓风前后获得的SAR图像，研究人员可以看到与洪水相关的地表移位状况（黄色和红色表示越来越明显的地表变化）。剧增的SAR数据使研究人员能够在更精细的尺度和频率上研究这些变化。

Flooding damage in the Bahamas, from Hurricane Dorian in 2019, was remotely assessed by NASA's Jet Propulsion Laboratory and the Earth Observatory of Singapore using synthetic aperture radar (SAR) data from Europe's Sentinel-1 satellites. By comparing SAR images acquired before and after the hurricane, researchers can see shifts in ground surface related to flooding (yellow and red indicate increasingly substantial surface change). A surge in SAR data is enabling researchers to study changes like these at finer scales and frequencies.

2021-03-05

封面图上展示的是巨噬细胞浸润腹膜腔伤口。像海胆一样原始的多细胞生物会把它们的器官藏在被巨噬细胞包围的体腔内——巨噬细胞能够对抗感染并修复组织。在哺乳动物中，巨噬细胞汇聚成类似血栓的结构以迅速封闭伤处。这一活动产生了意想不到的后果，例如手术后疤痕组织生长不良，现在可以有针对性地进行治疗。

Illustration of macrophages infiltrating a wound in the peritoneal cavity. Multicellular organisms as primitive as sea urchins harbor their organs in body cavities surrounded by macrophages—cells that fight infections and repair tissue. In mammals, macrophages assemble into thrombus-like structures to rapidly seal injuries. This activity has unintended consequences, such as undesirable growth of scar tissue after surgery, which can now be therapeutically targeted.

2021-03-12

封面图展示的是原子级薄度的硼，或硼墨烯，由于其独特的电子特性而引起了人们的注意。然而，由于硼墨烯具有很高的活性，所以只能在理想的真空条件下对其进行研究。硼墨烯可逆性加氢（图中右侧部分），是以平面形式存在的，可以合成氢化硼烯（图中左侧部分），一个带有原子氢的皱褶平面层（单个白色圆圈）。氢化硼烯的化学稳定性能够促进在电子、电池、传感器及量子技术等多领域的潜在应用发展。

Atomically thin boron, or borophene, has attracted attention because of its distinctive electronic properties. However, borophene is highly reactive, which makes it difficult to study outside of idealized vacuum conditions. Reversible hydrogenation of borophene (right), which exists as a flat sheet, enables synthesis of borophane (left), a puckered sheet with atomic hydrogen (individual white circles). Borophane's chemical stability may facilitate potential applications in electronics, batteries, sensors, and quantum technologies.

2021-03-19

封面图上通过艺术家的视角展示了9 300万年前的墨西哥湾，3只鹰鲨正在捕食浮游生物。这种新发现的晚白垩纪鲨鱼与新生代魔鬼鱼和蝠鲼的生态位相同，表明长有“翅状鳍”的滤食性动物在白垩纪末期危机前后在2个不同的软骨鱼类谱系中独立进化。

Artist's view of three eagle sharks (Aquilolamna milarcae) feeding on plankton in the Gulf of Mexico 93 million years ago. This newly described group of Late Cretaceous sharks (Aquilolamnidae) occupied the same ecological niche as Cenozoic devil and manta rays (Mobulidae), indicating that "winged" suspension feeders evolved independently in two distinct lineages of cartilaginous fishes before and after the end-Cretaceous crisis.