Overview of organic anion transporters and organic anion transporter polypeptides and their roles in the liver

Organic anion transporters(OATs)and organic anion transporter polypeptides(OATPs)are classified within two SLC superfamilies,namely,the SLC22A superfamily and the SLCO superfamily(formerly the SLC21A family),respectively.They are expressed in many tissues,such as the liver and kidney,and mediate the absorption and excretion of many endogenous and exogenous substances,including various drugs.Most are composed of 12 transmembrane polypeptide chains with the C-terminus and the N-terminus located in the cell cytoplasm.OATs and OATPs are abundantly expressed in the liver,where they mainly promote the uptake of various endogenous substrates such as bile acids and various exogenous drugs such as antifibrotic and anticancer drugs.However,differences in the locations of glycosylation sites,phosphorylation sites,and amino acids in the OAT and OATP structures lead to different substrates being transported to the liver,which ultimately results in their different roles in the liver.To date,few articles have addressed these aspects of OAT and OATP structures,and we study further the similarities and differences in their structures,tissue distribution,substrates,and roles in liver diseases.

Three-dimensional interconnected graphene network-based high-performance air electrode for rechargeable zinc‒air batteries

Although zinc-air batteries(ZABs)are regarded as one of the most prospective energy storage devices,their practical application has been restricted by poor air electrode performance.Herein,we developed a free-standing air electrode that is fabricated on the basis of a multifunctional three-dimensional interconnected graphene network.Specifically,a three-dimensional interconnected graphene network with fast mass and electron transport ability,prepared by catalyzing growth of graphene foam on nickel foam and then filling reduced graphene oxide into the pores of graphene foam,is used to anchor iron phthalocyanine molecules with atomic Fe-N_(4)sites for boosting the oxygen reduction during discharging and nanosized FeNi hydroxides for accelerating the oxygen evolution during charging.As a result,the obtained air electrode exhibited an ultra-small electrocatalytic overpotential of 0.603 V for oxygen reactions,a high peak power density of 220.2mWcm^(-2),and a small and stable charge-discharge voltage gap of 0.70 V at 10mA cm^(-2)after 1136 cycles.Furthermore,in situ Raman spectroscopy together with theoretical calculations confirmed that phase transformation of FeNi hydroxides takes place fromα-Ni(OH)_(x)toβ-Ni(OH)_(x)toγ-Ni^((3+δ)+)OOH for the oxygen evolution reaction and Ni is the active center while Fe enhances the activity of Ni active sites.