Thiophene-Containing Covalent Organic Frameworks for Overall Photocatalytic H2 O2 Synthesis in Water and Seawater.

H2 O2 is a significant chemical widely utilized in the environmental and industrial fields, with growing global demand. Without sacrificial agents, simultaneous photocatalyzed H2 O2 synthesis through the oxygen reduction reaction (ORR) and water oxidation reaction (WOR) dual channels from seawater is green and sustainable but still challenging. Herein, two novel thiophene-containing covalent organic frameworks (TD-COF and TT-COF) were first constructed and served as catalysts for H2 O2 synthesis via indirect 2e- ORR and direct 2e- WOR channels. The photocatalytic H2 O2 production performance can be regulated by adjusting the N-heterocycle modules (pyridine and triazine) in COFs. Notably, with no sacrificial agents, just using air and water as raw materials, TD-COF exhibited high H2 O2 production yields of 4060 µmol h-1 g-1 and 3364 µmol h-1 g-1 in deionized water and natural seawater, respectively. Further computational mechanism studies revealed that the thiophene was the primary photoreduction unit for ORR, while the benzene ring (linked to the thiophene by the imine bond) was the central photooxidation unit for WOR. The current work exploits thiophene-containing COFs for overall photocatalytic H2 O2 synthesis via ORR and WOR dual channels and provides fresh insight into creating innovative catalysts for photocatalyzing H2 O2 synthesis.

[Dose-effect relationship of irbsartan with the changes in the renal tissue structure in diabetic rats].

OBJECTIVE: To investigate the relationship between the dosage of irbesartan and the renal tissue structure in diabetic rats. METHODS: Male Wistar rats was given a single intraperitoneal dose (mg/kg) of streptozotocin to induce diabetes. The diabetic rats were randomized into 4 groups and received 4 weeks later 25 mg/kg (n=9), 50 mg/kg (n=9), 200 mg/kg (n=9) irbesartan intragastrically, or equal volume of water (model group, n=11) on a daily basis. Seven normal rats receiving with equal volume of water served as the normal control. All the rats were sacrificed after 8 weeks and the 24-hour albumin excretion, renal mass index and the volume of the glomerulus were measured. RESULTS: The 24-hour albumin excretion, renal mass index and volume of the glomerulus in the 3 irbesartan groups were significantly decreased as compare with those in the model group; the reductions in 50 and 200 mg/kg irbesartan groups were significant greater than those in 25 mg/kg irbesartan group. CONCLUSION: Irbesartan can decrease the 24-hour urinary albumin excretion and relive glomerulopathy in diabetic rats. Within a certain dose range, irbesartan produces a dose-dependent protective effect on the renal structures in the diabetic rats.