Multiple screws versus sliding hip screws in femoral neck fractures: A protocol of cohort study.

Background: There has been a paucity of cohort trials directly comparing multiple cannulated screws (MCS) and sliding hip screws (SHS) in femoral neck fractures at any level. Thus, a well-conducted clinical trial with an adequate sample size is urgently needed. We undertake a retrospective study to compare outcomes in patients who undertake MCS or SHS fixation for femoral neck fractures.

Dynamic regulation of CD28 conformation and signaling by charged lipids and ions.

CD28 provides an essential costimulatory signal for T cell activation, and its function is critical in antitumor immunity. However, the molecular mechanism of CD28 transmembrane signaling remains elusive. Here we show that the conformation and signaling of CD28 are regulated by two counteractive charged factors, acidic phospholipids and Ca ions.