New insight into enhanced photocatalytic selectivity of g-C3N4 by nitrogen vacancy introduction: Experimental study and theoretical calculation.

Constructing photocatalyst with both high efficiency and selectivity is highly desired in water treatment process. However, it is difficult to realize the selectivity of photocatalysis due to the non-selective oxidative species produced in this process. Herein, for the first time, the photocatalytic selectivity was achieved on g-C3N4 (CN) through N vacancy introduction for effective removal of organic pollutants, and the mechanism of vacancy induced selectivity enhancement was studied. The nitrogen vacancy modified CN (VCN) showed enhanced photocatalytic activity and unique selectivity towards phenolic compounds with electron-donating group, whose kinetic constant for p-aminophenol (p-NH2) degradation was 5.95 times higher than that over CN. Moreover, VCN photocatalytic system also displayed similar selectivity in binary pollutant systems. Characteristics and theoretical calculation results confirmed the enhanced photocatalytic performance and selectivity of VCN was mainly attributed to the effect of N vacancy. On one hand, electron-deficient N vacancy enhanced the adsorption of the O2 and phenolic compounds, which promoted the production of O2•- and strengthened the photocatalytic surface reaction. On the other hand, the N vacancy preferred to adsorb the electron-donating groups of phenolic compounds, which resulted in their selective removal.

Effects of Chaihu Shugan powder on hepatic lipid metabolism and AMPK/SIRT1 pathway in rats with non-alcoholic fatty liver disease / 中国病理生理杂志

[ ABSTRACT] AIM:To investigate the effects of Chaihu Shugan powder ( CSP) on lipid metabolism and the pro-teins involved in adenosine 5’-monophosphate-activated protein kinase (AMPK)/sirtuin 1 (SIRT1) pathway in the liver tissues of the rats with non-alcoholic fatty liver disease (NAFLD).METHODS: Sprague-Dawley rats were randomly di-vided into normal control ( NC) group, with HFD ( HFD) group and CSP group.The NAFLD models were established by feeding with HFD for 16 weeks in the rats.The rats in CSP group were intragastrically administered with CSP extracts (9.6 g· kg-1 · d-1 ) , and blood and liver samples were collected 16 weeks later.Serum and liver levels of total cholesterol ( TC) and triglyceride ( TG) , and serum levels of alanine aminotransferase ( ALT) and aspartate aminotransferase ( AST) were measured using an automatic biochemical analyzer.The histological changes of liver tissues were observed with HE staining, while the lipid deposition was observed with Oil Red O staining.The ultrastructural changes of the liver tissues were observed under transmission electron microscope.Moreover, the protein levels of AMPK, phosphorylated AMPK (pAMPK), SIRT1 and uncoupling protein 2 (UCP2) in the liver were detected by Western blot.RESULTS:The results of HE staining, Oil Red O staining and electron microscopy demonstrated that NAFLD rat model was successfully estab-lished.Compared with NC group, the serum and liver levels of TC and TG, and serum level of AST in model group were markedly elevated ( P<0.01) .Moreover, the protein levels of pAMPK and SIRT1 in HFD group were markedly reduced (P<0.01), whereas UCP2 level was elevated (P<0.01).Furthermore, liver levels of TC and TG, and serum level of AST in GSP group were markedly reduced as compared with HFD group ( P<0.05 ) .The protein levels of pAMPK and SIRT1 were elevated ( P<0.05 ) , whereas the UCP2 level was reduced as compared with HFD group ( P<0.01 ) .The protein level of AMPK between the 3 groups had no significant difference.CONCLUSION: CSP attenuates hepatic lipid disorder and hepatic lipid deposition in NAFLD rats induced by feeding with HFD for 16 weeks, which is associated with the activation of AMPK/SIRT1 pathway.