Abstract: Disclosed is a method of synthesizing high yield and high purity peptides with desired target amino acid sequences from solid phase within a short time period, using 2-(4-nitrophenylsulfonyl)ethoxycarbonyl-amino acids (Nsc-amino acids).

Abstract: Protected amino acid derivatives of general formula (I) and methods for the prepatation of the derivatives are provided.

Abstract: The specification describes an invention of calcification resistant bioprosthetic heart valves which can be used for a long term, and have good blood compatibility and in vivo stability, and have high calcification resistance. The bioprosthetic heart valves of the invention can be prepared by binding sulfonated polyethylene oxide (PEO) derivatives covalently to the tissue. The valves have an anionic effect equal to that of chondroitin sulfate, space filling effect, and blocking effect of the carboxyl group of collagen which has been known as one factor of the calcium deposition,. In particular, the present method has better advantages in view of calcification resistance than any other conventional methods, because it suppresses thrombosis and embolism and decreases incidence of infection.