2021-03-26

封面图展示的是一只秃鹰抓着一条鲱鱼飞过阿肯色州怀特河。秃鹰及其他野生动物可能会死于一种名为空泡性髓鞘病的神经系统疾病。生长在入侵水生植物上的蓝藻菌会产生致病的神经毒素，通过食物链自下而上影响野生动物。毒素的生物合成依赖于溴化物，因此监测和管理植物宿主、溴化物水平及神经毒素对保护野生动物和人类健康至关重要。

A bald eagle (Haliaeetus leucocephalus) clutches a shad as it flies over the White River in Arkansas. Bald eagles and other wildlife can succumb to vacuolar myelinopathy, a neurological disease. A cyanobacterium that grows on invasive aquatic plants produces the disease-causing neurotoxin, affecting wildlife in a bottom-up trophic cascade through the food chain. Toxin biosynthesis relies on bromide, so monitoring and management of the plant host, bromide levels, and neurotoxin are critical for protecting wildlife and human health.

2021-04-02

封面图展示的是通过计算设计的蛋白质（图中绿色部分）引导几乎所有抗体或Fc融合蛋白（图中黄色部分）组建成高度有序的纳米结构，其对称性范围涵盖从二面体到二十面体（黑色的结构示意图）。抗体对结构的形式和功能的构建均有贡献：双对称轴上的二聚体常数区域是纳米笼的关键结构元素，而面向外部的变量区域赋予纳米笼特定的靶向或信号功能。

Computationally designed proteins (green) direct the assembly of almost any antibody or Fc-fusion protein (yellow) into highly ordered nanostructures with symmetries ranging from dihedral to icosahedral (schematic of architecture in black). The antibodies contribute both form and function: The dimeric constant regions on the twofold symmetry axes are a key structural element of the nanocage, whereas the outward-facing variable regions endow the nanocage with a specific targeting or signaling function.

2021-04-09

封面图展示的是等离子体从一个强磁星中喷发出来的景象，强磁星是一颗中子星，其磁场比1块冰箱磁贴强大1万亿倍。地壳中的星震会释放出等离子体，它们在两极附近逸出。等离子体会产生一束伽玛射线，天文学家可以在地球上探测到这些射线。其中一些伽马射线耀斑证实了这张强磁星喷发图片的真实性，并且说明了这些天体可能相对来说是比较常见的。

In this artist's conception, plasma erupts from a magnetar, a neutron star with a magnetic field a trillion times stronger than that of a refrigerator magnet. Starquakes in the crust unleash the plasma, which escapes near the poles. The plasma generates a beam of gamma rays, which astronomers can detect on Earth. A handful of these gamma ray flares are confirming this picture of magnetar behavior and suggest that the objects may be relatively common.

2021-04-16

封面图展示的是雷克斯霸王龙在白垩纪的海岸边徘徊。科学家通过丰富的霸王龙化石记录，获取了包括体重、生长和存活曲线、地理范围、地质寿命等数据，将之与动物种群密度与体重的关系相对比，就有可能确定曾经有多少只霸王龙在这个星球上存活过，并估算出该物种的化石恢复概率。

Tyrannosaurus rex prowl a Cretaceous coast. By using the rich fossil record of T. rex, including its body mass, growth and survivorship curves, geographic range, and geologic longevity, together with the relationship between population density and body mass among living animals, it is possible to ascertain how many T. rex ver roamed the planet and to estimate the fossil recovery rate for this species.