胎盘组织核因子-κB与妊娠并发症关系研究进展

核因子-κB（NF-κB）是一种细胞内重要的转录因子，调控包括炎症、凋亡在内多种基因的表达，在胎盘中分布广泛。本文对胎盘组织中NF-κB与先兆子痫、HELLP综合征和胎膜早破等妊娠并发症的关系研究进行综述，概括了胎盘NF-κB在这些妊娠并发症发生过程中的作用以及依赖NF-κB途径治疗相关疾病的研究进展，为胎盘相关疾病的深入研究奠定基础，为妊娠并发症疾病的诊治提供新思路。

Effect of High-Temperature Ageing on Microstructure and Creep Properties of S31042 Heat-Resistant Steel

S31042 steel is a typical 25Cr-20Ni-type austenitic heat-resistant steel with excellent oxidation and corrosion resistance,and its creep rupture strength can be improved by the addition of Nb and N.This austenitic steel is widely used in superheater and reheater in ultrasupercritical power plants.At high temperatures,its performance is associated with the formation and evolution of Z,MX,and M23C6 phases.Till date,few studies have addressed the precipitation behavior of the Z phase in austenitic steel and the reinforcing mechanism of different M23C6 phases remains unclear.To clarify this,the ageing treatment of S31042 steel was performed at 1050oC,and the evolution behavior,thermal stability,and strengthening mechanism of the precipitates during creep tests were investigated.Furthermore,the relation between precipitate evolution and high-temperature performance was elucidated via OM,SEM,TEM,and creep tests.The supersaturation degree of the alloying components in solution-treated S31042 steel decreased after ageing at 1050oC and the driving force for M23C6 phase formation became smaller,resulting in a discontinuous distribution of the rod-like M23C6 phase along the austenite grain boundaries during the creep tests.At high stress levels,this discontinuous distribution of the rod-like M23C6 phase along the austenite grain boundaries increased the resistance to grain boundary sliding without changing the ductility,thus improving the rupture ductility of the steel.At low stress levels,the strengthening effects of the M23C6 phase discontinuously distributed along the austenite grain boundaries in aged steel were not as strong as those in solution-treated steel.