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The aim of the research is to study influence of combined nitrate-fluoride intoxication on the production of peroxynitrite (ONOO-) and superoxide anion radical (O2•-) in gastric mucosa of rats. Material and methods. We carried out experiments on 52 mature rats. Intoxication was modeled by intragastric administration of sodium fluoride and nitrate in a dose of 10 mg/kg and 500 mg/kg respectively. Total production of O2•-, ONOO- and concentration of thiobarbituric acid reactants (TBA-reactants) was determined in 10% homogenate of gastric mucosa. Results. We observed the highest ONOO- production from fluoride intoxication, while O2•- production was the highest under combined intoxication. The TBA-reactant concentration was the highest in fluoride intoxication group. Conclusion. Combined nitrate-fluoride intoxication intensifies lipid peroxidation by increased production of both O2•- and ONOO-.

In the conditions of the global ecological crisis in the world and Ukraine, the issue of finding alternative energy sources becomes relevant. One of the most common types of renewable energy is solar energy. In Ukraine today, the most promising direction of using solar energy is its direct transformation into low-potential thermal energy. To get electric power, solar radiation is the mere alternative to electric power generated from mined fuel, and without the pollution of air and water, or adverse consequences manifested in global warming. The disadvantage of this type of installation is the limitation of the duration of light time, as well as the effect of cloudiness. During the day, the number of solar radiation changes, to stabilize it is necessary to accumulate and accumulate it for further use, the technical implementation of stable operation of solar installation due to the use of terrestrial radiation and the accumulator of a specific part of solar energy is proposed. The purpose of the work is experimental studies to ensure the stable operation of the solar collector under cloudy conditions. The paper is aimed at the stabilization of the operation of the solar installation and to obtain additional heat after the Sun’s cloud cover. The use of a solar thermal collector is advisable in solar heating and hot water systems in conditions of alternating solar radiation. The results of physical modeling have proved the efficiency of the method of combining types of thermal radiation, due to the accumulation of energy it is possible to increase the quantitative index of solar energy in the conditions of cloudiness by 3 times.

Objectives: To assess the biochemical indicators of the connective tissue of rat periodontium (collagen, proteoglycans, glycoproteins) in local gum damage associated with lipopolysaccharide-induced systemic inflammatory response (SIR). Material and methods: The experiment involving 40 white Wistar rats was designed to evaluate the concentration of products of collagenolysis (free hydroxyproline), and the depolymerization of proteoglycans (glycosaminoglycans, GAG) and sialoglycoproteins (N-acetylneuraminic acid, NANA) in soft tissues of the periodontium (gum, periodontal ligament) and bone tissue of the alveolar process. Results. It has been found out that the application of 5% sodium hydroxide solution onto the gums during SIR induced by intraperitoneal injection of Salmonella typhi lipopolysaccharide (pyrogenal) in a dose of 0.4 μg/kg of weight three times during the 1st week and once a week for the next 7 weeks significantly increases the concentration of free hydroxyproline, GAG and NANA in the soft and bone periodontal tissues, exceeding that of a separate effect produced by alkali and bacterial lipopolysaccharide. Conclusions. The application of a local damaging agent (sodium hydroxide solution) to the gums in amount that in normal conditions does not produce any significant histological effect, can significantly enhance collagenolysis, depolymerization of proteoglycans and sialoglycoproteins in the soft and bone periodontal tissues in the presence of lipopolysaccharide-induced systemic inflammatory response.

Objectives: to investigate the effects produced by the combined action of L-arginine and the NF-κB inhibitor ammonium pyrrolidine dithiocarbamate (PDTC) on the markers of connective tissue disruption in the skin of white rats and its biomechanical properties under excessive intake of sodium nitrate. Material and methods. The studies were performed on 35 white Wistar rats. We assessed the concentration of collagenolysis and proteoglycans depolymerization products (free oxyproline, hexuronic acids) in the skin homogenate, as well as dermal tensometric characteristics. Results. It has been found out that a 30-day administration of sodium nitrate is accompanied by the following changes in the skin tissues: enhancement of the processes of collagenolysis and proteoglycans depolymerization, impairment of biomechanical skin properties (strength and elasticity). It has been shown that the combined administration of L-arginine (500 mg/kg) and PDTC (76 mg/kg) once every three days starting from the 15th day of nitrate intoxication, demonstrates much more pronounced effects in reducing the concentration of free oxyproline and hexuronic acids in the skin homogenate and improving skin tensometric indicators as compared with their separate administration. Conclusions. The combined effect of L-arginine and PDTC as a selective NF-κB inhibitor under nitrate intoxication is more effective than the isolated application of these substances. Their combined application limits the connective tissue disruption in the skin and improves its biomechanical properties.

This paper addresses the scientific and technical prospects and potential directions for the development of subterahertz astronomy in the Russian Federation. The concept of creating subterahertz instruments in the form of a universal compact antenna array for placement on the territory of the Russian Federation is proposed. It is possible to implement several space projects in the subterahertz range using such an antenna array, including a space interferometer and a telescope on the surface of the Moon. Ground-based compact antenna arrays will be able to act as a support for the very long baseline interferometer mode of the Millimetron observatory. [ABSTRACT FROM AUTHOR]

Until recently, the extracellular matrix was considered only a structural component of the organ, which performs exclusively the function of the framework. However, recent studies provide insight into a much broader role of extracellular matrix in metabolic homeostasis, the transmission of intra-organ and tissue signals. Metabolic syndrome and chronic infectious diseases can change the extracellular matrix’s structure in the heart. However, the combined effect of bacterial lipopolysaccharide and metabolic syndrome on extracellular matrix of the heart remains insufficiently elucidated at present. The purpose of this work is to establish the effect of organism stimulation with bacterial lipopolysaccharide on the concentration of different fractions of glycosaminoglycans, the intensity of collagenolysis and the content of sialic acids in the heart of rats under conditions of experimental metabolic syndrome. The study was conducted on 24 sexually mature rats of the “Wistar” line weighing 200-260 g. Animals were divided into 4 groups with 6 animals in each group: control, metabolic syndrome group, lipopolysaccharide injection group and combination of lipopolysaccharide injection and metabolic syndrome group. Metabolic syndrome was modelled by using 20% fructose solution as the only water source. Lipopolysaccharide of S. typhi was administered according to the scheme: the first week, 0.4 μg/kg 3 times intraperitoneally, then once a week 0.4 μg/kg throughout the experiment. Experiment lasted for 60 days. The concentration of glycosaminoglycans, their separate fractions, the content of free L-hydroxyproline and sialic acids was studied in 10% rat heart homogenate. The combined effect of stimulation of the organism with bacterial lipopolysaccharide and metabolic syndrome modeling led to an increase in the total concentration of glycosaminoglycans in the heart of rats by 73.46% compared to the control group. Under these conditions, the concentration of the heparin-heparan fraction of glycosaminoglycans in the heart of rats increased by 188.64% compared to the control group. The content of the keratan-dermatan fraction of glycosaminoglycans increased by 75.34%, and the chondroitin fraction of glycosaminoglycans increased by 17.63%. The concentration of free Lhydroxyproline increased by 167.23%. The content of sialic acids increased by 66.95%. Metabolic syndrome, stimulation of the organism with bacterial lipopolysaccharide and their combination lead to intensification of degradation of the extracellular matrix of the heart of rats due to increased collagenolysis, destruction of proteoglycans and glycoproteins. [ABSTRACT FROM AUTHOR]