A redox-responsive hyaluronic acid-vitamin E polyethylene glycol succinate nanoparticle loaded with paclitaxel (HA-SS-TPGS@PTX) was designed to investigate its mechanism for overcoming multidrug resistance (MDR) in non-small cell lung cancer (NSCLC) in vitro. HA-SS-TPGS@PTX nanoparticles were prepared using an emulsion-ultrasonication method. Techniques such as flow cytometry and confocal laser scanning microscopy (CLSM) were employed to study their effects on apoptosis induction, mitochondrial function, and the regulation of P-glycoprotein (P-gp) expression in PTX-resistant lung cancer cells (A549/T). Results showed that HA-SS-TPGS@PTX nanoparticles significantly inhibited the proliferation of A549/T cells in vitro, with an IC50 of 1.35 μg/mL. The nanoparticles entered the cells via CD44 receptor-mediated endocytosis. The high intracellular concentration of glutathione (GSH) triggered the release of PTX and TPGS, which subsequently induced a decrease in mitochondrial membrane potential, leading to apoptosis. Meanwhile, HA-SS-TPGS@PTX also inhibited P-gp expression and ATP consumption, thereby blocking drug efflux. The design of HA-SS-TPGS@PTX provides a new strategy for overcoming MDR in NSCLC.

Objective To explore changes in the capacity and working efficiency of divers performing deep saturation dives at various depths.Methods The divers completed the specified underwater operations at the depths of 70 m,255 m and 493 m,and changes in their working efficiency were assessed by working time and errors occurred during the underwater operations.Results The time consumed for the joining up of flanges,the binding and measurement of underwater objects at the depth of 255 m all significantly prolonged,when compared with the time used at 70 m(P <0.05).The time used for the joining up of flanges,the binding of underwa-ter objects at the depth of 493 m did not prolong significantly,when compared with the time spent at 255 m(P <0.05).However,the time used for underwater measurement prolonged significantly(P <0.01)and the rate of error both in the joining up of flanges and meas-urement of underwater objects increased significantly (P <0.05).Conclusion In deep saturation dives,the capability and working ef-ficiency of divers all considerably reduced.The greater the depths were,the more significantly their operating dexterity and short-term memory were affected.