目的:研究甘草苷抑制UVB诱导HaCaT细胞凋亡的机制。方法:以不同浓度的甘草苷作用于人皮肤角质形成细胞(HaCaT细胞),MTT法筛选药物的有效安全浓度;用30 m J/cm2的UVB照射HaCaT细胞,制备光老化模型,MTT法检测细胞增殖率;试剂盒法测定SOD、...目的:研究甘草苷抑制UVB诱导HaCaT细胞凋亡的机制。方法:以不同浓度的甘草苷作用于人皮肤角质形成细胞(HaCaT细胞),MTT法筛选药物的有效安全浓度;用30 m J/cm2的UVB照射HaCaT细胞,制备光老化模型,MTT法检测细胞增殖率;试剂盒法测定SOD、GSH-Px活性;流式细胞仪检测各组细胞中ROS含量和总凋亡率;Western Blot法检测各组细胞上清中Bax、Bcl-2蛋白表达量。结果:10-7、10-6、10-5mol/L甘草苷对HaCaT细胞无明显促增殖与抑制作用(P>0.05);甘草苷可提高SOD、GSH-Px活性,降低ROS含量和细胞凋亡率,抑制Bax蛋白的表达,促进Bcl-2蛋白的表达(P<0.05或P<0.01)。结论:甘草苷能抑制UVB诱导的HaCaT细胞凋亡,其机制可能与抗氧化损伤、抑制Bax蛋白的表达、促进Bcl-2蛋白的表达有关。展开更多
A new ultra-wide band （UWB） modulation scheme called L-ary ultra-wide band time hopping multi-pulse position modulation （UWB-TH-MPPM） is proposed for high data-rate wireless application, which can provide better c...A new ultra-wide band （UWB） modulation scheme called L-ary ultra-wide band time hopping multi-pulse position modulation （UWB-TH-MPPM） is proposed for high data-rate wireless application, which can provide better communication performance. The constant weight code is introduced to construct the MPPM signal and the comparison between MPPM and single pulse position modulation （SPPM） is done in three aspects, namely, power efficiency, bandwidth efficiency, and probability of symbol error, respectively. The theoretical analysis and the numerical results show that when the constant weight code is appropriately chosen, MPPM can achieve lower probability of symbol error and higher power efficiency than SPPM at the cost of more bandwidth under the same condition. The proposed MPPM can be a good candidate in UWB system design.展开更多
文摘目的:研究甘草苷抑制UVB诱导HaCaT细胞凋亡的机制。方法:以不同浓度的甘草苷作用于人皮肤角质形成细胞(HaCaT细胞),MTT法筛选药物的有效安全浓度;用30 m J/cm2的UVB照射HaCaT细胞,制备光老化模型,MTT法检测细胞增殖率;试剂盒法测定SOD、GSH-Px活性;流式细胞仪检测各组细胞中ROS含量和总凋亡率;Western Blot法检测各组细胞上清中Bax、Bcl-2蛋白表达量。结果:10-7、10-6、10-5mol/L甘草苷对HaCaT细胞无明显促增殖与抑制作用(P>0.05);甘草苷可提高SOD、GSH-Px活性,降低ROS含量和细胞凋亡率,抑制Bax蛋白的表达,促进Bcl-2蛋白的表达(P<0.05或P<0.01)。结论:甘草苷能抑制UVB诱导的HaCaT细胞凋亡,其机制可能与抗氧化损伤、抑制Bax蛋白的表达、促进Bcl-2蛋白的表达有关。
基金National Natural Science Foundation of China （60271018, 60331010） 0pen Fund of Key Lab of 0ptical Communication and Light-wave Technology （Beijing University of Posts and Telecommunications）, Ministry of Education, China.
文摘A new ultra-wide band （UWB） modulation scheme called L-ary ultra-wide band time hopping multi-pulse position modulation （UWB-TH-MPPM） is proposed for high data-rate wireless application, which can provide better communication performance. The constant weight code is introduced to construct the MPPM signal and the comparison between MPPM and single pulse position modulation （SPPM） is done in three aspects, namely, power efficiency, bandwidth efficiency, and probability of symbol error, respectively. The theoretical analysis and the numerical results show that when the constant weight code is appropriately chosen, MPPM can achieve lower probability of symbol error and higher power efficiency than SPPM at the cost of more bandwidth under the same condition. The proposed MPPM can be a good candidate in UWB system design.
