Effect of surface modification of electrodes on charge injection and dielectric characteristics of propylene carbonate

Space charge injected into a liquid dielectric by an electrode under an impulse voltage causes the electric field to be distorted,which affects the dielectric's insulation performance.In this study,the authors study the surface modification of three-electrode materials,namely aluminium,copper,and stainless steel,by sputtering of titanium dioxide(TiO2)based on magnetron sputtering.The breakdown voltage of propylene carbonate and the surface morphology of the electrodes before and after modification were examined.Furthermore,the distribution of the space charge injected into the propylene carbonate from the different electrode materials was also measured based on the Kerr electro-optic effect.These results indicate that the breakdown voltage of propylene carbonate increased by 7,4,and 9%after surface modification of aluminium,copper,and stainless steel,respectively.After sputtering of TiO2,micro-grooves on the surface of the three-electrode materials became smooth,and the surface roughness decreased,which changed the barrier height of the solid–liquid interface.The space charge injection mode of the three-electrode materials before and after surface modification was bipolar injection;however,the space charge injection amounts were markedly lower for the modified electrodes.

Glucagon-like peptide-1 receptor agonists rescued diabetic vascular endothelial damage through suppression of aberrant STING signaling

Glucagon-like peptide-1 receptor agonists(GLP-1 RAs)protect against diabetic cardiovascular diseases and nephropathy.However,their activity in diabetic retinopathy(DR)remains unclear.Our retrospective cohort study involving 1626 T2DM patients revealed superior efficacy of GLP-1 RAs in controlling DR compared to other glucose-lowering medications,suggesting their advantage in DR treatment.By single-cell RNA-sequencing analysis and immunostaining,we observed a high expression of GLP-1R in retinal endothelial cells,which was down-regulated under diabetic conditions.Treatment of GLP-1 RAs significantly restored the receptor expression,resulting in an improvement in retinal degeneration,vascular tortuosity,avascular vessels,and vascular integrity in diabetic mice.GO and GSEA analyses further implicated enhanced mitochondrial gene translation and mitochondrial functions by GLP-1 RAs.Additionally,the treatment attenuated STING signaling activation in retinal endothelial cells,which is typically activated by leaked mitochondrial DNA.Expression of STING mRNA was positively correlated to the levels of angiogenic and inflammatory factors in the endothelial cells of human fibrovascular membranes.Further investigation revealed that the cAMP-responsive element binding protein played a role in the GLP-1R signaling pathway on suppression of STING signaling.This study demonstrates a novel role of GLP-1 RAs in the protection of diabetic retinal vasculature by inhibiting STING-elicited inflammatory signals.