Laser fusion of selected dental casting alloys.

Laser-fused precious, nonprecious, and mixed metal welds were investigated for optimum weld energy requirement as determined by tensile strength tests. These strengths were compared to soldered unions. Laser fusion is as good as, or better than, unions created by conventional dental joining methods.

Studies on immunity to reinfection with Schistosoma mattheei in sheep and cattle.

Few experiments have been reported on immunity to reinfection in domestic stock. The degree of resistance to reinfection with S. mattheei was studied in cattle and sheep.

Studies on the isolation and purification of chloroplasts from Euglena gracilis.

A method has been developed for the isolation of chloroplasts from Euglena gracilis grown under mixotrophic conditions. This method utilizes sucrose density-gradient centrifugation in the AXII zonal rotor and allows the rapid preparation of large amounts of chloroplasts free from contaminating whole cells and other cytoplasmic materials. The majority of the isolated chloroplasts appear intact in phase contrast and electron micrographs.

Studies on heterologous immunity in schistosomiasis. 5. Heterologous schistosome immunity in sheep.

Previous studies have shown that when cattle are exposed to cercariae of Schistosoma mansoni they develop considerable resistance to subsequent challenge with S. mattheei. The present study showed that when sheep are immunized with S.