HIV-1 envelope glycoprotein (Env), a gp120–gp41 trimer, undergoes coordinated conformational changes that drive membrane fusion and allow immune evasion by transiently concealing ...

The dorsal raphe nucleus (DRN) serotonergic (5-HT) system has been implicated in regulating sleep and motor control; however, its specific role remains controversial. In this study, we found that ...

How much do you know about Shakespeare’s play Romeo and Juliet? This section takes you step by step through the play, helping you to identify key plot points. If you’ve heard of Romeo and Juliet, ...

Hinge joints allow flexion and extension only. Flexion – bending a joint. This occurs when the angle of a joint decreases. For example, the elbow flexes when performing a biceps curl. The knee flexes ...