[Efficiency of assessment of retinol, alpha-tocopherol and beta-carotene by the liquid chromatography method].

Benign prostatic hyperplasia is very frequent disease of the primogenital system of elderly men. As the investigations show the antioxidant vitamins have various influence on the men's organism. They participate in the pathogenesis of many diseases.

Electric field induced order reconstruction in a nematic cell.

We have experimentally observed the biaxial switching between two topologically distinct textures of a nematic liquid crystal cell submitted to a strong electric field. The effect is deduced from optical and electrical measurements across the cell. Above a static threshold, a bulk order reconstruction is observed, where the final nematic orientation in the centre becomes perpendicular to its initial one, inducing a total pi change of orientation across the cell.

Electro-optic effect in an optically active nematic chiral liquid-crystal structure.

A new electro-optic effect in an optically active nematic chiral structure beyond Mauguin's region has been studied. The effect is revealed in the absence of oscillations of the transmission-voltage curve, low requirements for orienting surfaces, and the ability to function at any direction of polarization of incident light. The limit relationships among wavelength, helical path, and optical anisotropy of the nematic matrix are determined.