The natural ways of degradation of pesticides based on 2,4-dichlorophenoxyacetic acid

To increase crop yields by destroying weeds the separate group of pesticides exist, that is called herbicides. Among the herbicides based on chlorphen oxalcanecarboxylic acids products of sodium and ammonium salts, as well as 2,4-dichlorophenoxyacetic acid (2,4-D), are widely used. However, the production and use of pesticides affects the state of the environment and pose a potential risk for public health. In this paper the need to clarify the mechanisms of transformation and degradation of 2,4-D de-rivatives under the action of physical, chemical and biological environmental factors was showed. The preparations based on 2,4-D, registered in the Republic of Belarus is reviewed. The mechanisms of action of these xenobiotics are described, analysis of their toxicity for the environment components is performed. Particular attention is paid to the microbial degradation of pesticides, possible ways of their degradation under the action of microorganisms enzyme systems are described, the factors, that affect the biotransformation process are an alyzed. It has been shown that th e bacterial degradation of 2,4-D is carried with the formati on of 2,4-dichlorophenol by en zyme 2,4-dihlorphenoxyacetate-α-ketog-lutaratedioxygenase, and further the intermediate degrades with 3,5-dihlorocatechol formation using 2,4-dihlorphenolhydroxylase in two ways: or tho-splitting or peripheral meta-splitting

Change in the karyotype of the embryo as a cause of spontaneous abortion in the first trimester

Currently, one of the most actual health problems in the world is the problem of a spontaneous abortion. Chromosomal abnormalities are one of the main reasons of early abortion, stillbirth or the birth of a child with multiple congenital malformations. The results of karyotyping of chorionic villi from 149 patients with diagnoses of "undeveloped pregnancy" or "anembryonia" were presented in the article. Metaphase chromosomes were used for cytogenetic research of the embryos. The samples were obtained from cytotrophoblast cells of chorionic villi by the "direct" method, without culture, according to standard technique. A GTG-method was used for staining the chromosome slides. The cytogenetic study of chorionic villi makes it possible to identify the karyotype abnormalities, which caused the fading of pregnancy, since the chorion karyotype corresponds to the embryo karyotype The slide analysis was carried out in accordance with the international system of the human cytogenetic nomenclature. As a result of the cytogenetic study, changes in the karyotype were revealed in 53.39 % of the samples, namely, genomic mutations – aneuploidy and polyploidy. Among the aneuploidies, we found the embryos with trisomy in the autosomes 5, 13, 16, 18, 20, 21, and 22. In addition, the karyotypes with trisomy and monosomy of the X chromosome, as well as the male karyotypes with an additional copy of the X or Y chromosome were present The polyploids in the study group were represented by triploid and tetraploid karyotypes of embryos. All the above mentioned karyotype disorders were found in both full and mosaic forms. Further, some non-developing embryos contained a chimeric karyotype - "chi46,XX/46,XY". In the study group, the prevailing were the embryos with a tetraploid karyotype in a mosaic form (6.71 %), Klinefelter syndrome in a mosaic form (6.04 %), and a triploid karyotype in a mosaic form (6.04 %). A statistically significant increase in the incidence of stillbirths with mosaic tetraploid karyotype was found in 2020. The share of this pathology was 25. %. Currently, there is no reliable information on the effect of the SARS-CoV-2 virus on the embryonic genome. Nevertheless, it is known that members of the coronavirus family are responsible for serious complications during pregnancy - pregnancy fading, fetal growth retardation, premature birth, death of the mother or fetal death in the neonatal period. In this connection, we can hypothesize that mitotic disorders and, as a consequence, appearance of embryos with a tetraploid karyotype seem to be associated with a mild SARS-CoV-2 infection that occurs in pregnant women in an inconspicuous form

Investigation the structure and properties of deformed semi-finished products produced from chips of Al–Mg alloys system alloyed with scandium

The article presents the results of studies that make it possible to solve the problem of processing secondary waste from expensive aluminum alloys without irretrievable loss of metal. For this purpose, tasks were set and solved for the development of technological schemes for obtaining longish deformed semi-finished products from chip waste of Al–Mg alloys 01570 and 1580 alloyed with scandium using methods of powder metallurgy and metal forming. For their experimental verification, the operations of chip briquetting, combined rolling-extrusion (continuous extrusion), sectional rolling, hot extrusion and drawing in combination with heat treatment were applied. According to these schemes, semi-finished products in the form of rods and wires were obtained. Structure and mechanical properties were investigated. It has been revealed that when hot-extruded rods are obtained from chip briquettes of alloy 01570 on a vertical hydraulic press, even with significant degrees of deformation during extrusion, the margin of plastic properties is small and makes it possible to obtain a wire with a diameter of only 4.2 mm after drawing. The processing of briquettes from 1580 alloy chips using the combined rolling-extrusion method makes it possible to obtain after cold deformation a wire with a diameter of up to 3 mm. At the same time, the influence of the annealing process on the structure and properties of deformed semi-finished products from the investigated alloys was studied. It is shown that due to the low plasticity of the investigated material cold working of the rods must be carried out with small degrees of deformation, alternating it with intermediate annealing according to the proposed regime. An analysis of the physical and mechanical properties of the wire obtained using combined processing showed that its strength and plastic properties are comparable to the properties of the wire obtained from a cast billet, and the structure is characterized by a high degree of elaboration and compactness. Thus, as a result of the research, technological schemes have been developed and processing parameters have been determined for the production of rods and wire from graded chip waste of alloys 01570 and 1580 using compaction, discrete and continuous extrusion, as well as cold drawing. © 2022 The AuthorsMinistry of Education and Science of the Russian Federation, Minobrnauka: FSRZ-2020-0013The research was carried out within the framework of the state assignment of the Ministry of Science and Higher Education of the Russian Federation (scientific theme code FSRZ-2020-0013)

The natural ways of degradation of pesticides based on 2,4-dichlorophenoxyacetic acid

To increase crop yields by destroying weeds the separate group of pesticides exist, that is called herbicides. Among the herbicides based on chlorphen oxalcanecarboxylic acids products of sodium and ammonium salts, as well as 2,4-dichlorophenoxyacetic acid (2,4-D), are widely used. However, the production and use of pesticides affects the state of the environment and pose a potential risk for public health. In this paper the need to clarify the mechanisms of transformation and degradation of 2,4-D de-rivatives under the action of physical, chemical and biological environmental factors was showed. The preparations based on 2,4-D, registered in the Republic of Belarus is reviewed. The mechanisms of action of these xenobiotics are described, analysis of their toxicity for the environment components is performed. Particular attention is paid to the microbial degradation of pesticides, possible ways of their degradation under the action of microorganisms enzyme systems are described, the factors, that affect the biotransformation process are an alyzed. It has been shown that th e bacterial degradation of 2,4-D is carried with the formati on of 2,4-dichlorophenol by en zyme 2,4-dihlorphenoxyacetate-α-ketog-lutaratedioxygenase, and further the intermediate degrades with 3,5-dihlorocatechol formation using 2,4-dihlorphenolhydroxylase in two ways: or tho-splitting or peripheral meta-splitting