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Nanofibers of Al 2 O 3 (commercial product Nafen TM ) with characteristic length of 100 nm and diameter of 10 nm were used to create new hybrid materials based on copolymer of ethylene and propylene. Nanocomposites were obtained by in situ catalytic copolymerization on the system rac-Et(2-MeInd) 2 ZrMe 2 /isobutylalumoxane. Formation of the nanocomposites with uniform distribution of Nafen nanoparticles in polymer matrix was confirmed by scanning and transmission electron microscopy. According to dynamic mechanical analysis data, introduction of the nanofiller in an amount of up to 3 wt % leads to an increase in glass transition temperature by 10 8C (E 00 ) and by 21 8C (tan d). The nanocomposites exhibit improved physico-mechanical properties (tensile strength and elongation at break). It is shown that the nanofiller significantly improves resistance of the nanocomposite to the thermo-oxidative and thermal degradation.

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A two-year observation was carried out over schoolchildren in order to find out the possibility of preventing dental caries by replacing sugar with xylitol. Replacement of 30 g of sweets per day with xylitol led to a significant decrease in the incidence of caries in permanent teeth and had a beneficial effect on the clinical course of caries.

As a result of a two-year study of the features of dental and periodontal lesions in mineral acid production workers and the provision of dental care to this contingent, a three-stage dental medical examination of chemical production workers has been developed.