Kyushu University

About: Kyushu University is a education organization based out in Fukuoka, Japan. It is known for research contribution in the topics: Population & Catalysis. The organization has 68284 authors who have published 135190 publications receiving 3055928 citations. The organization is also known as: Kyūshū Daigaku.

Grain boundaries in ultrafine grained materials processed by severe plastic deformation and related phenomena

Abstract: Grain boundaries in ultrafine grained (UFG) materials processed by severe plastic deformation (SPD) are often called “non-equilibrium” grain boundaries. Such boundaries are characterized by excess grain boundary energy, presence of long range elastic stresses and enhanced free volumes. These features and related phenomena (diffusion, segregation, etc.) have been the object of intense studies and the obtained results provide convincing evidence of the importance of a non-equilibrium state of high angle grain boundaries for UFG materials with unusual properties. The aims of the present paper are first to give a short overview of this research field and then to consider tangled, yet unclear issues and outline the ways of oncoming studies. A special emphasis is given on the specific structure of grain boundaries in ultrafine grained materials processed by SPD, on grain boundary segregation, on interfacial mixing linked to heterophase boundaries and on grain boundary diffusion. The connection between these unique features and the mechanical properties or the thermal stability of the ultrafine grained alloys is also discussed.

Postoperative liver failure after major hepatic resection for hepatocellular carcinoma in the modern era with special reference to remnant liver volume

Abstract: Background: Postoperative liver failure is a life-threatening complication after hepatic resection. Because of recent advances in liver surgery technique and a more stringent patient selection, mortality after hepatic resection has steadily decreased, but its incidence still ranges from 10% to 20%. The factors linked to postoperative liver failure in major hepatic resection in the modern era should be reevaluated. Study Design: Of 80 patients with viral markers (hepatitis C viral antibody or hepatitis B surface antigen) who underwent major hepatic resections (no less than bisegmentectomies) for hepatocellular carcinoma between 1990 and 1996, 7 patients (8.8%) died of postoperative liver failure within 6 months after hepatectomy. The cause of liver failure was analyzed based on both the preoperative data and the intraoperative findings. In addition, since all the patients who died of liver failure underwent a right hepatic lobectomy, a further data analysis was also done in 47 patients who underwent a right lobectomy of the liver. A volumetric analysis by CT was then done to evaluate the remnant liver volume. Results: Between the patients with liver failure and those without liver failure who underwent a right lobectomy, there were no significant differences in preoperative data or intraoperative findings. Volumetric analysis revealed that the remnant liver volume of patients who died of liver failure was significantly smaller than that of patients who lived (p = 0.008). The incidence of liver failure in patients with a remnant liver volume of less than 250 mL/m 2 was 7 of 20 (38%), while it was 0 of 27 in patients with a liver volume of no less than 250 mL/m 2 (p = 0.0012). The only significant risk factor for liver failure in patients with a remnant liver volume of less than 250 mL/m 2 was diabetes mellitus (p = 0.0072). Conclusions: The expected remnant liver volume appears to be a good predictor for liver failure in patients who undergo a right lobectomy of the liver. In patients with diabetes mellitus and an expected remnant liver volume of less than 250 mL/m 2 , a major hepatectomy should be avoided. Careful patient selection based on volumetric analysis in major hepatectomy cases could help prevent the occurrence of postoperative liver failure.