Abstract: A stiffness matrix H? is designed as PiTCPi or a linear combination form thereof, where a spatial first-order difference operator, which operates on a state vector, of a displacement vector at each discrete grid point is Pi and the matrix of elastic constants is C. The mass matrix T? is derived using finite-difference approximations at the discrete grid points so that the result of the matrix ?Tnum operating on a state vector corresponding to rotations or translations is 0, where T is a positive definite diagonal mass matrix and ?Tnum=T??T.

Abstract: A stiffness matrix H? is designed as PiTCPi or a linear combination form thereof, where a spatial first-order difference operator, which operates on a state vector, of a displacement vector at each discrete grid point is Pi and the matrix of elastic constants is C. The mass matrix T? is derived using finite-difference approximations at the discrete grid points so that the result of the matrix 8Tnum operating on a state vector corresponding to rotations or translations is 0, where T is a positive definite diagonal mass matrix and ?Tnum=T??T.

Abstract: A medicinal composition which comprises a compound of the formula:CH.sub.3 (CH.sub.2)nCH.dbd.CHCO.sub.2 Hwherein n represents 10, 12, 14 or 16, or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier; a method for testing diabetes or improving lipid metabolism by the administration of said composition to a human being; and a process for the separation of said compounds from freshwater clam which comprises subjecting freshwater clam to the extraction with hot water and/or an aprotic solvent and then purifying the resultant.