Antioxidant activity and protective effect of hydroxy derivatives of chalcones for sterlet (Acipenser ruthenus, Linnaeus, 1758) sperm.

The aim of this work is to study the effect of adding hydroxy derivatives of chalcones to the basic cryomedium on the ability of sterlet sperm to utilize superoxide and hydrogen peroxide, the intensity of lipid peroxidation of male fish germ cells, and their viability both before cryopreservation and after 3 days of freezing at liquid nitrogen temperature. The ability of phenolic derivatives of chalcones to increase the superoxide dismutase and catalase activities of sterlet sperm and to reduce the intensity of lipid peroxidation has been established. The antioxidant activity of the derivatives exceeds the effect of Trolox, which inhibits the functioning of the enzyme component of the antioxidant protection of fish sperm and promotes lipid peroxidation of fish sperm before cryopreservation.

Oxidative stress and cryoresistance of sturgeon sperm: A review.

Currently, the majority of sturgeons are relict fishes of high economic value yet endangered with extinction. Cryopreservation of sperm has great potential in fish farming and conservation, but the problem of low cryoresistance of sturgeon sperm has not yet been solved. The goal of this work was to review current literature data on the causes of low tolerance of sturgeon sperm to cryodamage.

Concentration-dependent dielectric and electro-optical properties of composites based on nematic liquid crystals and CdS:Mn quantum dots.

Composites in a wide concentration range of 0-0.6 wt% based on a nematic liquid crystal mixture and CdS quantum dots doped with manganese ions (Mn 6%) are presented. The effect of the CdS:Mn quantum dots on the phase diagram and electronic structure of composites was studied using differential scanning calorimetry and fluorescence analysis.

Use of cryoprotectors and antioxidants in sturgeon semen cryopreservation.

In recent years, the possibility of increasing the low cryoresistance of sturgeon sperm by using antioxidants in basic cryoprotective media has been studied. The goal of this work was to review the current literature on impact of the cryoprotectors, well-known antioxidants and new multifunctional compounds on the activity indicators and fertilizing capability of sperm, as well as on biomarkers of cryostress. A special attention is given to the radical scavenging activity of studied compounds in relation to the highly reactive oxygen species, to prevent and negate oxidative stress damage of sturgeon sperm.

The Effect of the Stress State, Testing Temperature, and Hardener Composition on the Strength of an AlMg5/Epoxy Metal-Polymer Joint.

The regularities of the effect of a complex stress state on the strength of an AlMg5/epoxy adhesive joint are experimentally studied at -50 and +23 °C in tension+shear and compression+shear tests with different normal-to-shear stress ratios. The tests use modified Arcan specimens and Brazil-nut-sandwich specimens, with the lateral faces of the adhesive layer having a shape of a mushroom-like "ridge" aimed at reducing stress concentration at the specimen edges. An original computational model of a selected microvolume including the interface together with the adjacent substrate and adhesive layers is used to process the experimental results.