Analysis of apparent fracture toughness of a thick-walled FGM cylinder with two diametrically opposed edge cracks

This study focuses on the analysis of apparent fracture toughness of a thick-walled functionally graded material (FGM) cylinder with two diametrically opposed edge cracks emanating from the inner surface of the cylinder. The crack surfaces and the inner surface of the cylinder are subjected to an internal pressure. The incompatible eigenstrain developed in the cylinder due to non-uniform coefficient of thermal expansion after cooling from sintering temperature is taken into account. Based on a generalized method of evaluating stress-intensity factor developed in our previous study, an approach is presented to evaluate apparent fracture toughness. To demonstrate the approach, some numerical results of apparent fracture toughness are presented for a TiC/Al₂O₃ FGM cylinder. The effects of material distribution, cylinder wall thickness, application temperature and number of cracks on apparent fracture toughness are investigated in details. It is found that all these factors play an important role in controlling apparent fracture toughness of a thick-walled FGM cylinder.     

Quality of life is not related with liver disease severity but with anemia, malnutrition, and depression in HCV-infected hemodialysis patients

Hepatitis C virus (HCV) infection may deteriorate quality of life. The relationship between HCV infection and quality of life in hemodialysis (HD) patients is unknown. The demographic characteristics, comorbidities, biochemical parameters, and Malnutrition-Inflammation Score (MIS) were recorded. Child-Pugh classification, Beck Depression Inventory, and SF-36 were performed. Liver histopathology was examined. Thirty-two patients (21 Child-Pugh-A, 11 Child-Pugh-B) were included. There was high-grade portal necroinflammatory activity in 14, high-grade lobular necroinflammatory activity in 26, and hepatic fibrosis in 19 patients. Three patients had cirrhosis. Patients with a high stage of liver fibrosis had lower social functioning scores than patient with a low stage of fibrosis (P= 0.011). The only correlation was between aspartate aminotransferase and the physical function subscale (r=−0.395, P= 0.025). None of the SF-36 scores differed between Child-Pugh A and B patients. Instead, most of the SF-36 subscale and summary scores were related with hemoglobin, albumin, MIS and Beck Depression Score. Quality of life in HCV-infected HD patients was independent of liver disease severity anchors, but was correlated with anemia, malnutrition, and depression.