Nanocrystalline 2J4 alloy was fabricated by equal-channel angular pressing (ECAP). Microstructural evolution at different passes of ECAP and the effect of angle (φ) on the ECAP were researched. The results reveal th...Nanocrystalline 2J4 alloy was fabricated by equal-channel angular pressing (ECAP). Microstructural evolution at different passes of ECAP and the effect of angle (φ) on the ECAP were researched. The results reveal that α phase slowly turns to γ phase and follows the formation of dislocation cells in the 2J4 alloy with increasing severe plastic deformation. At last, it becomes reasonably finer bands of subgrains. The results with intersect at angle (φ) of 90° are better than that at angle (φ) of 120°. After three passes of ECAP, at angle φ of 90°, nanocrystalline microstructure can be obtained. The grain size is reduced from 30μm in the initial state to 400nm.展开更多
In the perifused fura-2 loaded exocrine pancreatic acinar cell line AR4-2J pulses of high potassium induced repetitive increases in intracellular calcium. Attached cells when stimulated with high potassium secreted la...In the perifused fura-2 loaded exocrine pancreatic acinar cell line AR4-2J pulses of high potassium induced repetitive increases in intracellular calcium. Attached cells when stimulated with high potassium secreted large amount of amylase. High potassium-induced secretion was dependent both on the concentration of potassium and duration of stimulation. High potassium induced increases in intracellular calcium were inhibited by voltage-dependent calcium channel antagonists with an order of potency as follows: nifedipine > ω-agatoxin IVA > ω-conotoxin GVIA. In contrast, the L-type calcium channel antagonist nifedipine almost completely inhibited potassium-induced amylase secretion, whereas the N-type channel antagonist ω-conotoxin GVIA was without effect. The P-type channel antagonist ω-agatoxin IVA had a small inhibitory effect, but this inhibition was not significant at the level of amylase secretion. In conclusion, the AR4-2J cell line possesses different voltage-dependent calcium channels (L, P,N) with the L-type predominantly involved in depolarization induced amylase secretion.展开更多
文摘Nanocrystalline 2J4 alloy was fabricated by equal-channel angular pressing (ECAP). Microstructural evolution at different passes of ECAP and the effect of angle (φ) on the ECAP were researched. The results reveal that α phase slowly turns to γ phase and follows the formation of dislocation cells in the 2J4 alloy with increasing severe plastic deformation. At last, it becomes reasonably finer bands of subgrains. The results with intersect at angle (φ) of 90° are better than that at angle (φ) of 120°. After three passes of ECAP, at angle φ of 90°, nanocrystalline microstructure can be obtained. The grain size is reduced from 30μm in the initial state to 400nm.
文摘In the perifused fura-2 loaded exocrine pancreatic acinar cell line AR4-2J pulses of high potassium induced repetitive increases in intracellular calcium. Attached cells when stimulated with high potassium secreted large amount of amylase. High potassium-induced secretion was dependent both on the concentration of potassium and duration of stimulation. High potassium induced increases in intracellular calcium were inhibited by voltage-dependent calcium channel antagonists with an order of potency as follows: nifedipine > ω-agatoxin IVA > ω-conotoxin GVIA. In contrast, the L-type calcium channel antagonist nifedipine almost completely inhibited potassium-induced amylase secretion, whereas the N-type channel antagonist ω-conotoxin GVIA was without effect. The P-type channel antagonist ω-agatoxin IVA had a small inhibitory effect, but this inhibition was not significant at the level of amylase secretion. In conclusion, the AR4-2J cell line possesses different voltage-dependent calcium channels (L, P,N) with the L-type predominantly involved in depolarization induced amylase secretion.
