Two sulfur-containing ansamycin antibiotics were isolated from the culture broth of Streptomyces albolongus C-46366; the major one was identical with awamycin and the minor one was a new ansamycin antibiotic, ansathiazin. Their structures were elucidated from their reactions and spectroscopic analyses. These antibiotics were active against gram-positive bacteria, acid-fast bacteria and a protozoan.
Free-machining stainless steel containing sulfur has been continuously cast in square shape of 165 mm 165 mm and its surface grade and hot-workability as well as mechanical property have been tested under various casting conditions. The results are summarized as follows; (1) The increase in sulfur content in the range 0.014 to 0.32 wt% decreased the surface quality. The number of transverse cracks on the surface depended on the property of mold powders used. The mold powders with slow melting property and low viscosity after melting decreased remarkably the number of the surface cracks. (2) The number of the longitudinal cracks was related to the carbon content and to the secondary cooling rate. When the carbon content was more than 0.09 wt% and the secondary cooling rate was 0.8 1/kg, internal cracks have been observed in the as-cast blooms. (3) Surface smoothing by mechanical polishers was very effective for the improvement of the hotworkability of the cast blooms. A deep oscillation mark behaved as a notch upon hot rolling. A succssful hot-rolling was practiced, only when the ratio of manganese content to sulfur content was more than 9.0 and the oxygen content was less than 130ppm.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.