[Intensity of processes of oxidative modification of proteins in women's and cow's milk].

Breast milk is a source of all the essential nutritional components necessary for the full growth and development of the child, therefore, it is necessary to study its composition and physical and chemical properties in order to adapt human milk substitutes. Adapted infant milk formulas are produced mainly from cow's milk, bringing formula nutrient composition closer to the composition of women's milk, adapting it in accordance with the requirements of the infant body. However, technological processes for the production of dairy products contribute to the activation of oxidative reactions, the violation of protein conformation. The purpose of the study was to compare the intensity of formation of carbonyl derivatives of human and cow's milk proteins during spontaneous and metal-catalyzed oxidation. Material and methods. The object of the study were samples of mature milk of healthy nursing mothers (n=12), and samples of drinking ultra-pasteurized milk for baby nutrition (n=8) which were used as a comparison material. The intensity of oxidative modification of milk proteins was determined spectrophotometrically by the interaction of carbonyl derivatives of amino acid residues with 2.4-dinitrophenylhydrazine to form 2.4-dinitrophenylhydrazone derivatives in a native sample of biological material and under induction of protein oxidation in vitro by the Fenton reaction by adding FeSO4 and hydrogen peroxide solutions. The content of nonprotein sulfhydryl groups was determined after protein precipitation spectrophotometrically with 5.5'-dithio-bis-2-nitrobenzoic acid. Results. The intensity of spontaneous (basic) oxidation doesn't have significant differences between the indicators of breast and cow's milk. Significant differences were established in the content of carbonyl derivatives of amino acid residues of human and cow's milk proteins during metal-catalyzed oxidation. Incubation with iron ions caused 1.5-2.5 fold more formation of both aldehyde and ketone derivatives of cow's milk proteins, recorded in the visible and ultraviolet spectrum. In cow's milk during spontaneous oxidation and induction of oxidation by a metal, the percentage of aldehyde-dinitrophenylhydrazones was lower than in breast milk and, conversely, the proportion of ketone-dinitrophenylhydrazones, late markers of oxidative degradation of proteins, was significantly higher. The content of non-protein sulfhydryl groups in cow's milk was 2 times less than in fresh human milk. A significant excessive content of aldehyde-dinitrophenylhydrazones (2 times) and ketone-dinitrophenylhydrazones (2.6 times) undet metal-catalyzed protein oxidation of cow's milk in comparison with breast milk indicates a lower level of antioxidant reserves of cow's milk. This is confirmed by the reduced level of non-protein sulfhydryl groups. The results obtained indicate the need to improve the antioxidant status of dairy products for infant nutrition.

[TRANSFORMATION OF ADVERTISING COMMUNICATIONS UNDER THE INFLUENCE OF THE COVID-19 PANDEMIC].

The global coronavirus pandemic (COVID-19) has led to changes in advertising, marketing, advertising spending and media activities, forcing companies and brands to rethink their views on current and future advertising and marketing campaigns in order to maintain a stable revenue stream. This becomes even more important, because as a result of COVID-19, it is expected that starting in 2020, in the future, at least for the next 4-5 years, advertising costs for some advertisers will decrease as revenue decreases and the transition to other forms and channels of communication with the target audience of consumers. As a result, many brands may seek to optimize their marketing practices to better reflect the growth of online transactions, communication, and personal interaction time with consumers.

[The effect of advertising activity on patients' choice of medical organization].

The article presents theoretical propositions concerning placement and dissemination of information about medical organization and practical recommendations of the advertising campaign of medical services. The analysis of the advertising activities' influence on the patient choice of the medical organization out of top annual revenue medical institutions in Russia was carried out. In economically developed countries, the support of possibility of choosing particular medical organization and physician in economic theory and in practice of organization of health care system is targeted to improving medical care quality and health care efficiency. The process of expanding possibilities of choice is officially declared as one of the priorities of development of Russian health care. However, the influence of consumer choice of patient of medical organization while addressing for medical care is still to be an object of research study in Russia.

[Occupational hygiene and health status in welders of laser devices]. / Gigiena truda i sostoianie zdorovía svarshchikov-sborshchikov lazernykh uchastkov.

Welders-assemblers of the Quant-type laser devices are exposed to bright light flashes of plasma and laser exceeding in certain measurements the maximal allowed level. Such hazards induce disorders in eyes, autonomic nervous, circulatory and immune systems of workers. Impaired humoral immunity can lead to increased incidence of acute respiratory tract diseases. Prophylactic measures, including laser and flash shielding screens and drug therapy were suggested.

[The biological effects and criteria for assessing the danger of laser radiation]. / Biologicheskie éffekty i kriterii otsenki opasnosti lazernogo izlucheniia.

Biological effects of laser radiation (LR) are determined by the absorption properties of the irradiated tissues and physiological characteristics of radiation. The high intensities of the effect are accompanied by melting, evaporation, substance ionization, formation of shock and acoustic waves. Under the action of the low-intensity LR there prevail photochemical, photobiological and thermal processes. The action of LR of one or another wave length is determined by the initial stages of its interaction with biological substrate. The biostimulating action of LR is widely used in clinical medicine. On the contrary, the effects that give rise to morphofunctional lesions of biological tissues determine the necessity of elaborating preventive measures ensuring protection of man from LR. It is generally accepted that thresholds of the damaging action on the retina and skin may be used as the main criterion for maximum allowable level (MAL) basing. In addition to the changes observable in the directly irradiated tissues, many authors point to a possibility of functional disturbances on the part of certain organs and systems of the body, followed by the formation of asthenic and vegetovascular syndromes. The experimental and clinical data confirm that the body may develop common nonspecific changes which, together with the local damaging effects, can be regarded as criteria for an adverse action of LR and, therefore, taken into account in MAL derivation.