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Biomedical subjects

R Zahradník

Publications and source records attributed to R Zahradník.

8 recordsLinked to original sources
PubMed1990

[Fluoride ions and apatite recrystallization of apatite in enamel].

The authors discuss the basic process on which the principle of fluoridation in based--i.e. the mutual exchange of F- ions and the OH- group in hydroxyapatite of enamel. Model investigations assessing the energy difference between hydroxyapatite and F- and fluorapatite and the OH- group indicate that fluorapatite tends to release steadily fluoride ions and to change into hydroxyapatite. This tendency, apparently inopportune from the aspects of caries prevention, ensures, however, a permanent low F- level above the enamel surface. The presence of F- ions facilitates recrystalization of apatite in the initial caries stage. The investigation tries to throw new light, from the point of view of theoretical chemistry at a molecular level, on the mechanism of remineralization, one of the most important ways which implements the preventive action of fluoride.

Crystallization↗
PubMed1971

Molecular-orbital study of hydroxylation of collagenous proline and lysine.

EHT and CNDO/2 types of calculations permit the interpretation of the course of hydroxylation of collagenous proline and lysine. Calculations were performed for the models of proline (I), zwitterion of proline (II), proline-containing peptide (III), and lysine (IV). The theoretical results are consistent with an electrophilic mechanism.

Collagen↗