[What is the damage gamma-irradiation on solutions-cryoconservants at 77 K?].

Originating under the gamma-radiation action at 77 K on glassy phosphate solutions (6 mol/l) of glycerol and glycero-1-phosphate, H-atoms have motility by virtue of tunneling effect and react with the stabilized radicals of a matrix (OH /H2O+) and with solutes: at storage them in liquid nitrogen the radicals of separation H from carbon atoms C1 and C2 will be derived. According to the assessment maximal radiation "damage" is plotted to the investigated system for year, approximately 1 mol/l.

[Free-radical mechanism of chitosan radiation degradation and problems of the chemical antiradiation protection].

An analysis of published data on the radiolytic properties of chitosan and of some modelling its fragments substances was performed. The main process of radiation chitosan degradation is connected with the formation and conversion of free radicals. The mechanisms of the primary radicals C2, C1 and C3 (of the NH2 and H removal radicals) conversion up to the formation of some terminal products of chitosan radiolysis were offered in the form of the generalized schemes.

[About the "double" radioprotecting mechanism of some sulfur-containing substances].

The hypothesis about the double-acting mechanism of some radioprotectors during the irradiation of the DNA solutions is expressed in literature: the water radicals interception and the formation up to the irradiation of the additional intermolecular bonds "protector-DNA" (stabilization of the double helix). The realization conditions of this hypothesis were obtained by the molecular mechanics methods and the free radical mechanism appearance of the intrastrand cross-links "protector-DNA" during the irradiation of the polymer is given.

[On control of radioactive-chemical protection and point mutations by inhibitors of free radical reactions].

An opportunity to control the DNA protection against radiation in cells and the formation of 2-desoxyribose residue epimers (sites of potential point mutations) by using a set of free radical scavengers differing by parameters of availability (molecular mask and access window) is discussed. The values of steric probability (efficiency) of formation of a chemical bond between atoms Cn of a 2-desoxyribosyl radical (n from 1 to 5) and H-atom of a scavenger donor group were determined. It was shown that the maximum effect of radioprotection determined, for example, by transformations of C2 radical reached 25% (4-oxy-3,5-di-tert-butyl-alpha-methylbenzylamine) and maximum yield of C4-epimer was 15.

[The role of adsorbed water in polysaccharide radiation destruction].

The role of water in the potato starch destruction during gamma-irradiation of native starch preparations with various equilibrium humidity (5-45%) and starch jellies (systems with different quantity of polymer structured water) has been studied. The scheme reactions of the formation of primary radicals and molecular products of radiolysis in the system "structured starch--water" is also given.