Reduction of Residual Stresses in Sapphire Cover Glass Induced by Mechanical Polishing and Laser Chamfering Through Etching

Sapphire is a hard and anti-scratch material commonly used as cover glass of mobile devices such as watches and mobile phones. A mechanical polishing using diamond slurry is usually necessary to create mirror surface. Additional chamfering at the edge is sometimes needed by mechanical grinding. These processes induce residual stresses and the mechanical strength of the sapphire work piece is impaired. In this study wet etching by phosphate acid process is applied to relief the induced stress in a 1” diameter sapphire cover glass. The sapphire is polished before the edge is chamfered by a picosecond laser. Residual stresses are measured by laser curvature method at different stages of machining. The results show that the wet etching process effectively relief the stress and the laser machining does not incur serious residual stress

Reduction of Residual Stresses in Sapphire Cover Glass Induced by Mechanical Polishing and Laser Chamfering Through Etching

Sapphire is a hard and anti-scratch material commonly used as cover glass of mobile devices such as watches and mobile phones. A mechanical polishing using diamond slurry is usually necessary to create mirror surface. Additional chamfering at the edge is sometimes needed by mechanical grinding. These processes induce residual stresses and the mechanical strength of the sapphire work piece is impaired. In this study wet etching by phosphate acid process is applied to relief the induced stress in a 1” diameter sapphire cover glass. The sapphire is polished before the edge is chamfered by a picosecond laser. Residual stresses are measured by laser curvature method at different stages of machining. The results show that the wet etching process effectively relief the stress and the laser machining does not incur serious residual stress

Glutathione peroxidase 8 negatively regulates caspase‐4/11 to protect against colitis

Abstract Human caspase‐4 and its mouse homolog caspase‐11 are receptors for cytoplasmic lipopolysaccharide. Activation of the caspase‐4/11‐dependent NLRP3 inflammasome is required for innate defense and endotoxic shock, but how caspase‐4/11 is modulated remains unclear. Here, we show that mice lacking the oxidative stress sensor glutathione peroxidase 8 (GPx8) are more susceptible to colitis and endotoxic shock, and exhibit reduced richness and diversity of the gut microbiome. C57BL/6 mice that underwent adoptive cell transfer of GPx8‐deficient macrophages displayed a similar phenotype of enhanced colitis, indicating a critical role of GPx8 in macrophages. GPx8 binds covalently to caspase‐4/11 via disulfide bonding between cysteine 79 of GPx8 and cysteine 118 of caspase‐4 and thus restrains caspase‐4/11 activation, while GPx8 deficiency leads to caspase‐4/11‐induced inflammation during colitis and septic shock. Inhibition of caspase‐4/11 activation with small molecules reduces the severity of colitis in GPx8‐deficient mice. Notably, colonic tissues from patients with ulcerative colitis display low levels of Gpx8 and high caspase‐4 expression. In conclusion, these results suggest that GPx8 protects against colitis by negatively regulating caspase‐4/11 activity