Birefringence effect studies of collagen formed by nonenzymatic glycation using dual-retarder Mueller polarimetry.

Significance: Nonenzymatic glycation of collagen covalently attaches an addition of sugar molecules that initially were involved in a reversibly reaction with amino groups on the protein. Due to the ultimate formation of stable irreversible advanced glycation end products, the process of glycation leads to abnormal irreversible cross-linking, which ultimately accumulates with age and/or diabetes in the extracellular matrix, altering its organization.

Aim: We report the use of dual-retarder Mueller polarimetry in conjunction with phase retardance to differentiate collagen cross-linking in a normal collagen gel matrix from that in tissues with nonenzymatic cross-linking.

[AAS method for determination of manganese in fluorspar].

An AAS method for the determination of manganese in fluorspar was established for the inspection of export product. The fluorspar sample was treated with HF, then fumed with HClO4. After cooling, the residue was dissolved by adding HCl and boric acid with gentle heating.