We investigated whether the presence of hepatitis C virus (HCV) infection can be detected in hemostatic gauze used during oral treatments. We were able to detect both antibody to HCV and HCV RNA in samples from patients serologically proven to have HCV and also in gauze used for these patients that was left at room temperature even for as long as 24 hours. Thus, this method is useful for the screening of HCV infection in situations in which blood sampling is not feasible.

Surface hardening by laser irradiation was examined regarding the loss factor, which is the parameter of the vibration-damping characteristics, for flake graphite cast irons and spherical graphite cast irons. The surface of the samples was quenched by changing speed of beam, gas pressure, and beam frequency. It was found that the depth of the hardening region was from 0.12 mm to 1.11 mm, and the hardness of the boundary between the hardening and the nonhardening regions changed suddenly. It was confirmed that the loss factor of the laser hardened specimens increased considerably as compared with that of the as-cast specimens. The internal friction at the vicinity of the boundary between the hardening and the nonhardening regions may be responsible for this result.