Abstract: The present invention provides an absorbable barrier membrane for guided tissue regeneration which is useful for regeneration of animal tissues, including those of humans, the absorbable barrier membrane being superior in heat stability, processability, reproducibility, storage stability, bioabsorbablity, and tissue regeneration effects, and further provides a method for regeneration, using the absorbable barrier membrane, of a mandible, periodontal tissue, or defective tubulous bone, and particularly a defective tubulous bone which possesses a segmental bone defect in which both ends of the bone are in separate segments. The above objects are attained by an absorbable barrier membrane for use in guided tissue generation, comprising a lactic copolyester in which a polymerization catalyst is deactivated, as an essential component.

Abstract: A method for growing a single crystal of a cubic boron nitride semiconductor in a growing container sealed under high pressure and high temperature conditions, which comprises dissolving in a dopant-containing boron nitride solvent a boron nitride starting material placed at a high temperature zone in the growing container, and providing a temperature gradient to the solvent so that the temperature dependence of the solubility is utilized to let the single crystal form and grow at a low temperature zone in the growing container.