This article presents the results of the 10-fold cyclic freezing (−37.0 °C) and thawing (0.0 °C) effect on the number and size range of silver nanoparticles (AgNPs). AgNPs were obtained by the cavitation-diffusion photochemical reduction method and their sorption on the fiber surface of various suture materials, perlon, silk, and catgut, was studied. The distribution of nanoparticles of different diameters before and after the application of the cyclic freezing/thawing processes for each type of fibers studied was determined using electron microscopy. In general, the present study demonstrates the effectiveness of using the technique of 10-fold cyclic freezing. It is applicable to increase the absolute amount of AgNPs on the surface of the suture material with a simultaneous decrease in the size dispersion. It was also found that the application of the developed technique leads to the overwhelming predominance of nanoparticles with 1 to 15 nm diameter on all the investigated fibers. In addition, it was shown that after the application of the freeze/thaw method, the antibacterial activity of silk and catgut suture materials with AgNPs was significantly higher than before their treatment by cyclic freezing.

The effect of a reduced deuterium (D) content in the incubation medium on the survival of cultured neurons in vitro and under glucose deprivation was studied. In addition, we studied the effect of a decrease in the deuterium content in the rat brain on oxidative processes in the nervous tissue, its antioxidant protection, and training of rats in the T-shaped maze test under hypoxic conditions. For experiments with cultures of neurons, 7–8-day cultures of cerebellar neurons were used. Determination of the rate of neuronal death in cultures was carried out using propidium iodide. Acute hypoxia with hypercapnia was simulated in rats by placing them in sealed vessels with a capacity of 1 L. The effect on oxidative processes in brain tissues was assessed by changes in the level of free radical oxidation and malondialdehyde. The effect on the antioxidant system of the brain was assessed by the activity of catalase. The study in the T-maze was carried out in accordance with the generally accepted methodology, the skill of alternating right-sided and left-sided loops on positive reinforcement was developed. This work has shown that a decrease in the deuterium content in the incubation medium to a level of −357‰ has a neuroprotective effect, increasing the survival rate of cultured neurons under glucose deprivation. When exposed to hypoxia, a preliminary decrease in the deuterium content in the rat brain to −261‰ prevents the development of oxidative stress in their nervous tissue and preserves the learning ability of animals in the T-shaped maze test at the level of the control group. A similar protective effect during the modification of the ²H/¹H internal environment of the body by the consumption of DDW can potentially be used for the prevention of pathological conditions associated with the development of oxidative stress with damage to the central nervous system.

The aim was to investigate prooxidant-antioxidant system in the blood and brain homogenates functional activity in rats with acute hypoxia model with different deuterium/protium (D/H) ratios in drinking diet. Studies have shown that consuming DDW (–665 ‰) within 8 weeks lead to deuterium concentration decrease in blood plasma at 317 ‰ and brain at 209 ‰ of rats, in comparison to control group, consuming natural water. DDW consumption before hypoxia modeling in rats improves antioxidant defense enzymes (catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase) activity in the blood, increasing its antioxidant potential by 20 %, while free radical oxidation intensity in plasma and biomolecules peroxide modification rate in erythrocytes. Also, in brain tissues consuming DDW, there were no abnormalities in catalase, superoxide dismutase activity, and it was noted increase (by 71 %) in reduced thiol-containing compounds concentration, which reduces nerve hypoxi? cell damage risk. Neuroprotective effect presence is confirmed by higher (by 32 %) antioxidant activity markers of lyophilized brain tissues, and by free radical oxidation lower intensity (by 13 %) and biomolecules oxidative modification rate (by 16 %) in these lyophilized tissues. Thus, the advisability of using DDW neuroprotective effects in cerebral circulation disturbance in experimental and clinical practice.

The deuterium content modification in an organism has a neuroprotective effect during the hypoxia model, affecting anxiety, memory and stress resistance. The aim of this work was to elucidate the possible mechanisms of the medium D/H composition modification on nerve cells. We studied the effect of an incubation medium with a 50 ppm deuterium content compared to a medium with 150 ppm on: (1) the activity of Wistar rats’ hippocampus CA1 field neurons, (2) the level of cultured cerebellar neuron death during glucose deprivation and temperature stress, (3) mitochondrial membrane potential (MMP) and the generation of reactive oxygen species in cultures of cerebellar neurons. The results of the analysis showed that the incubation of hippocampal sections in a medium with a 50 ppm deuterium reduced the amplitude of the pop-spike. The restoration of neuron activity was observed when sections were returned to the incubation medium with a 150 ppm deuterium content. An environment with a 50 ppm deuterium did not significantly affect the level of reactive oxygen species in neuron cultures, while MMP decreased by 16–20%. In experiments with glucose deprivation and temperature stress, the medium with 50 ppm increased the death of neurons. Thus, a short exposure of nerve cells in the medium with 50 ppm deuterium acts as an additional stressful factor, which is possibly associated with the violation of the cell energy balance. The decrease in the mitochondrial membrane potential, which is known to be associated with ATP synthesis, indicates that this effect may be associated with the cell energy imbalance. The decrease in the activity of the CA1 field hippocampal neurons may reflect reversible adaptive changes in the operation of fast-reacting ion channels.

The article is devoted to the main soil treatment with a combined plow. The article has a research character, which is expressed in the fact that the analysis of methods and means of mechanization for the main tillage with the turnover of a layer, as well as excerpts from the works of leading scientists on the problem, there were shown the types of patents that provided the optimal soil treatment, their shortcomings and solutions to these problems. There were determined the main trend of development of soil-processing combined machines, improvement of constructions of arable units to improve the quality of their work. Also, the form of the disk was justified, namely, there was shown the causal relationship of the presence of cuts in the disk of the tillage tool in comparison with the solid disk. There were described the principle and process of the developed combined plow. As a result of the work done, there was obtained the design of a combined plow with additional working bodies which consist of disks installed by batteries behind each body of the plow. The conclusions set out the main results achieved so far.