[Characterization of the biological properties of acid-treated chrysotile-asbestos fibers].

Boiling of chrysotile of the textile brand PRZh1-50 in concentrated hydrochloric acid for 10, 15, and 20 minutes gave rise to three chrysotile-asbestos samples. The content of MgO decreased from to 24, 19, and 9%, respectively. As compared with the baseline values, the number and force of positively charged electrical centers were less in the samples containing 24 and 19% MgO and more in the sample having 9% MgO; the negatively charged centers were present in the former two samples and absent in the third one.

[The electric properties of fiber surface and the toxicity of asbestos].

Thermal treatment, autoclaving and their combination yielded 3 samples of chrysotile-asbestos. With these, as compared with parent Type PRZh-1-50 Bazhenov chrysotile, the structure of fibers deteriorated and the number of negative discharges increased in the first two samples; the superficial structure substantially increased and the number of positive centers greatly decreased in the third sample. The ratio of positive to negative centers was less in all treated samples than that in the parent one, it decreased particularly during combined treatment.

[Interaction of poly-2-methyl-5-vinyl-N-ethylpyridinium bromide and heparin studied by means of ultraviolet and infrared spectroscopy].

Antithrombotic properties are induced in polymers used in vascular surgery by modifying their surface chemically by introducing heparin by means of quaternary bases. The authors have studied the interaction of heparin with quaternary polyvinylpyridinium bromide. Optimal conditions for obtaining this complex have been established.