目的初步探讨血镉及胎盘11β-羟基类固醇脱氢酶2(11β-hydroxysteroid dehydrogenase type 2,11β-HSD2)与重度子痫前期的相关性及镉与11β-HSD2参与重度子痫前期发生的机制。方法选取32例重度子痫前期妊娠孕妇为研究组及同期孕检正常孕...目的初步探讨血镉及胎盘11β-羟基类固醇脱氢酶2(11β-hydroxysteroid dehydrogenase type 2,11β-HSD2)与重度子痫前期的相关性及镉与11β-HSD2参与重度子痫前期发生的机制。方法选取32例重度子痫前期妊娠孕妇为研究组及同期孕检正常孕妇32例为正常妊娠组,测定2组孕妇血镉水平和胎盘中11β-HSD2表达水平。结果与正常妊娠组相比,研究组重金属镉水平升高,11β-HSD2表达降低(P<0.05)。结论血镉与11β-HSD2可能参与了重度子痫前期的发生发展。展开更多
Propane dehydrogenation(PDH)on Ga/H-ZSM-5 catalysts is a promising reaction for propylene production,while the detail mechanism remains debatable.Ga_(2)O_(2)^(2+) stabilized by framework Al pairs have been identified ...Propane dehydrogenation(PDH)on Ga/H-ZSM-5 catalysts is a promising reaction for propylene production,while the detail mechanism remains debatable.Ga_(2)O_(2)^(2+) stabilized by framework Al pairs have been identified as the most active species in Ga/H-ZSM-5 for PDH in our recent work.Here we demonstrate a strong correlation between the PDH activity and a fraction of Ga_(2)O_(2)^(2+) species corresponding to the infrared GaH band of higher wavenumber(GaHHW)in reduced Ga/H-ZSM-5,instead of the overall Ga_(2)O_(2)^(2+) species,by employing five H-ZSM-5 supports sourced differently with comparable Si/Al ratio.This disparity in Ga_(2)O_(2)^(2+) species stems from their differing capacity in completing the catalytic cycle.Spectroscopic results suggest that PDH proceeds via a two-step mechanism:(1)C-H bond activation of propane on H-Ga_(2)O_(2)^(2+) species(rate determining step);(2)β-hydride elimination of adsorbed propyl group,which only occurs on active Ga_(2)O_(2)^(2+) species corresponding to GaHHW.展开更多
文摘目的初步探讨血镉及胎盘11β-羟基类固醇脱氢酶2(11β-hydroxysteroid dehydrogenase type 2,11β-HSD2)与重度子痫前期的相关性及镉与11β-HSD2参与重度子痫前期发生的机制。方法选取32例重度子痫前期妊娠孕妇为研究组及同期孕检正常孕妇32例为正常妊娠组,测定2组孕妇血镉水平和胎盘中11β-HSD2表达水平。结果与正常妊娠组相比,研究组重金属镉水平升高,11β-HSD2表达降低(P<0.05)。结论血镉与11β-HSD2可能参与了重度子痫前期的发生发展。
文摘Propane dehydrogenation(PDH)on Ga/H-ZSM-5 catalysts is a promising reaction for propylene production,while the detail mechanism remains debatable.Ga_(2)O_(2)^(2+) stabilized by framework Al pairs have been identified as the most active species in Ga/H-ZSM-5 for PDH in our recent work.Here we demonstrate a strong correlation between the PDH activity and a fraction of Ga_(2)O_(2)^(2+) species corresponding to the infrared GaH band of higher wavenumber(GaHHW)in reduced Ga/H-ZSM-5,instead of the overall Ga_(2)O_(2)^(2+) species,by employing five H-ZSM-5 supports sourced differently with comparable Si/Al ratio.This disparity in Ga_(2)O_(2)^(2+) species stems from their differing capacity in completing the catalytic cycle.Spectroscopic results suggest that PDH proceeds via a two-step mechanism:(1)C-H bond activation of propane on H-Ga_(2)O_(2)^(2+) species(rate determining step);(2)β-hydride elimination of adsorbed propyl group,which only occurs on active Ga_(2)O_(2)^(2+) species corresponding to GaHHW.
