Developing Cu single-atom catalysts(SACs)with well-defined active sites is highly desirable for producing CH4 in the electrochemical CO_(2) reduction reaction and understanding the structure-property relationship.Here...Developing Cu single-atom catalysts(SACs)with well-defined active sites is highly desirable for producing CH4 in the electrochemical CO_(2) reduction reaction and understanding the structure-property relationship.Herein,a new graphdiyne analogue with uniformly distributed N_(2)-bidentate(note that N_(2)-bidentate site=N^N-bidentate site;N_(2)≠dinitrogen gas in this work)sites are synthesized.Due to the strong interaction between Cu and the N_(2)-bidentate site,a Cu SAC with isolated undercoordinated Cu-N_(2) sites(Cu1.0/N_(2)-GDY)is obtained,with the Cu loading of 1.0 wt%.Cu1.0/N_(2)-GDY exhibits the highest Faradaic efficiency(FE)of 80.6% for CH_(4) in electrocatalytic reduction of CO_(2) at-0.96 V vs.RHE,and the partial current density of CH_(4) is 160 mA cm^(-2).The selectivity for CH_(4) is maintained above 70% when the total current density is 100 to 300 mA cm^(-2).More remarkably,the Cu1.0/N_(2)-GDY achieves a mass activity of 53.2 A/mgCu toward CH4 under-1.18 V vs.RHE.In situ electrochemical spectroscopic studies reveal that undercoordinated Cu-N_(2) sites are more favorable in generating key ^(*)COOH and ^(*)CHO intermediate than Cu nanoparticle counterparts.This work provides an effective pathway to produce SACs with undercoordinated Metal-N_(2) sites toward efficient electrocatalysis.展开更多
目的:观察血管生成素-1/重组质粒(pEGFP/Ang-1)转染的大鼠骨髓间充质干细胞(BMSCs)对高浓度葡萄糖损伤猴脉络膜-视网膜内皮细胞(RF/6A)的保护作用。方法:以pEGFP/Ang-1转染BMSCs,倒置荧光显微镜下观察增强型绿色荧光蛋白的表达,再利用Tr...目的:观察血管生成素-1/重组质粒(pEGFP/Ang-1)转染的大鼠骨髓间充质干细胞(BMSCs)对高浓度葡萄糖损伤猴脉络膜-视网膜内皮细胞(RF/6A)的保护作用。方法:以pEGFP/Ang-1转染BMSCs,倒置荧光显微镜下观察增强型绿色荧光蛋白的表达,再利用Transwell模型,将转染的BMSCs与RF/6A共培养于高浓度葡萄糖培养基中。3d后MTT法检测RF/6A活力,Western blot检测磷酸化蛋白激酶B(phosphorylated protein kinase B,P-PKB)的表达,从而探讨转染pEGFP/Ang-1的BMSCs对高浓度葡萄糖培养中的RF/6A的保护作用。结果:成功转染pEGFP/Ang-1的BMSCs可见增强型绿色荧光蛋白表达,与转染pEGFP/Ang-1的BMSCs共培养的RF/6A细胞活力及P-PKB的表达均高于未转染组(均P<0.01),与对照组无明显差别(均P>0.05)。结论:质粒pEGFP/Ang-1转染的BMSCs对高糖环境中的RF/6A具有保护作用,其机制可能与P-PKB表达上调有关。展开更多
文摘Developing Cu single-atom catalysts(SACs)with well-defined active sites is highly desirable for producing CH4 in the electrochemical CO_(2) reduction reaction and understanding the structure-property relationship.Herein,a new graphdiyne analogue with uniformly distributed N_(2)-bidentate(note that N_(2)-bidentate site=N^N-bidentate site;N_(2)≠dinitrogen gas in this work)sites are synthesized.Due to the strong interaction between Cu and the N_(2)-bidentate site,a Cu SAC with isolated undercoordinated Cu-N_(2) sites(Cu1.0/N_(2)-GDY)is obtained,with the Cu loading of 1.0 wt%.Cu1.0/N_(2)-GDY exhibits the highest Faradaic efficiency(FE)of 80.6% for CH_(4) in electrocatalytic reduction of CO_(2) at-0.96 V vs.RHE,and the partial current density of CH_(4) is 160 mA cm^(-2).The selectivity for CH_(4) is maintained above 70% when the total current density is 100 to 300 mA cm^(-2).More remarkably,the Cu1.0/N_(2)-GDY achieves a mass activity of 53.2 A/mgCu toward CH4 under-1.18 V vs.RHE.In situ electrochemical spectroscopic studies reveal that undercoordinated Cu-N_(2) sites are more favorable in generating key ^(*)COOH and ^(*)CHO intermediate than Cu nanoparticle counterparts.This work provides an effective pathway to produce SACs with undercoordinated Metal-N_(2) sites toward efficient electrocatalysis.
文摘目的:观察血管生成素-1/重组质粒(pEGFP/Ang-1)转染的大鼠骨髓间充质干细胞(BMSCs)对高浓度葡萄糖损伤猴脉络膜-视网膜内皮细胞(RF/6A)的保护作用。方法:以pEGFP/Ang-1转染BMSCs,倒置荧光显微镜下观察增强型绿色荧光蛋白的表达,再利用Transwell模型,将转染的BMSCs与RF/6A共培养于高浓度葡萄糖培养基中。3d后MTT法检测RF/6A活力,Western blot检测磷酸化蛋白激酶B(phosphorylated protein kinase B,P-PKB)的表达,从而探讨转染pEGFP/Ang-1的BMSCs对高浓度葡萄糖培养中的RF/6A的保护作用。结果:成功转染pEGFP/Ang-1的BMSCs可见增强型绿色荧光蛋白表达,与转染pEGFP/Ang-1的BMSCs共培养的RF/6A细胞活力及P-PKB的表达均高于未转染组(均P<0.01),与对照组无明显差别(均P>0.05)。结论:质粒pEGFP/Ang-1转染的BMSCs对高糖环境中的RF/6A具有保护作用,其机制可能与P-PKB表达上调有关。
