A simple two-step method for isolation and purification C-peptide from human proinsulin using hydrophobic chromatography on Octylsepharose and gel-permeation chromatography on Bio-gel P-4 was developed. Also optimum conditions for the HPLC-analysis of C-peptide were found. The structure of the C-peptide was proved by the determination of the first five N-amino acid residues and C-terminal fragments. Also the 28 amino acid residues were determined using authomatic method Edman. C-peptide can be applied in the preparation of the test-systems for diagnostic of some diseases.

The three-dimensional heat-conduction problem is solved for a multilayer domain with a local source in one of the layers. The numerical results of the solution are analyzed in application to the layered structure of a semiconductor integrated circuit.