The choice of analytes’ powder-carrier for preparing calibration samples when analyzing welding fumes using X-ray fluorescence

Введение. Рассмотрены процессы образования твердой составляющей сварочных аэрозолей (ТССА); показано, что частицы ТССА отличаются фазовым и химическим составом, дисперсностью в зависимости от свариваемых материалов и условий сварки; основными фазами является магнетит Fe₃O₄ и железомарганцевая шпинель MnFe₂O₄. Проблема. Определение градуировочных характеристик недеструктивных методик рентгенофлуоресцентного анализа (РФА) и проверка правильности методик количественного химического анализа ТССА осложнены отсутствием стандартных образцов. Создание аттестованных смесей, адекватных реальным пробам ТССА, собранным на фильтр, затруднено из-за сложности их физико-химических свойств. Эксперимент. Приготовлены синтетические образцы в виде тонкой органической пленки, содержащей порошковые соединения элементов, контролируемых в ТССА. Проведены исследования по выбору порошкового носителя аналитов для создания аттестованных смесей. Оценено максимальное значение размера зерен порошка, когда эффектом микроабсорбционной неоднородности можно пренебречь на фоне случайной погрешности изготовления пленочных аттестованных смесей. Экспериментально доказано, что в качестве порошка-носителя аналитов при создании градуировочных образцов для недеструктивных методик РФА проб ТССА допустимо применять любые соединения аналитов, если размер их частиц менее 4 мкм. Результаты. Создан комплект пленочных аттестованных смесей, которые можно рекомендовать в качестве градуировочных образцов для недеструктивных методик РФА; погрешность их изготовления характеризуется коэффициентом вариации 5-6 %.The processes of forming the solid component of welding fumes (SCWF) are considered; the particles of SCWF are shown to differ in phase and chemical composition, and dispersion depending on welding materials and welding conditions; the magnetite Fe₃O₄ and the iron-manganese spinel MnFe₂O₄ are the main phases. The determination of calibration characteristics of non-destructive techniques and the validation of the techniques for quantitative chemical analysis of SCWF are complicated by the lack of certified reference materials. The development of certified mixtures, appropriate to real samples of SCWF collected on a filter, is difficult because of the complexity of their physical and chemical properties. The synthetic samples were prepared in the form of an organic thin film containing the powder compounds of elements controlled in the SCWF. The studies were conducted to choose the powder-carrier of analytes for developing the certified mixtures. The maximum size value of powder grains were estimated when the effect of micro absorption heterogeneity can be neglected on the background of random error in preparing film certified mixtures. It is experimentally proven that any analyte compounds are suitable for use as a powder-carrier of analytes in developing the calibration samples for the non-destructive techniques of X-ray fluorescence analysis (XRF) of SCWF samples if their particle sizes are less than 4 microns. A set of film certified mixtures was developed, which can be recommended as the calibration samples for the non-destructive XRF techniques; the error in their preparation is characterized by the variation coefficient of 5-6 %

Electroless deposition and Electroplating of Metals

The present paper summarizes the main results of the research on the electroless and electrochemical metal deposition from aqueous solutions, which has been carried out in the Research Institute of Physical-Chemical problems of the Belarussian State University and at the Department of Inorganic Chemistry of the BSU for the last three decades. The paper covers the following problems: the main peculiarities of electroless and electrochemical deposition of copper, nickel, Ni-B,Ni-P, gold films 0.1-30 mkm and more in thickness, their phase composition, morphology and properties; the characteristic features of of hydrometallurgic allowing (e.g. electroless and electrochemical deposition of a number of binary alloy coatings such as Cu-Ni, Cu-Cd, Cu-Sn, Cu-Zn, Ni-Sn, Ni-W, Ni-Mo), methods of their chemical and phase composition and microstructure regulation, together with correlation between these parameters and alloy properties; the methods for composite metal and alloy film plating from solutions with production of materials including metal oxides and thus possessing unusual and useful properties; the peculiarities of metal film plating onto dielectrics with production of continuous films and metal conductive patterns without the use of photoresists

Анализ инновационных технологий гидрогелей из уронатных полисахаридов и биодеградирующих пленок на их основе

The article is devoted to the analysis of the state and dynamics of scientific developments in the field of creating products for life and health, based on hydrogels from uronate polysaccharides (HUP). The article is reflected the results of the global scientific research monitoring and their changes in the field of technologies for the creation and use of HUP. The results of a retrospective analysis of existing technologies based on poorly studied in the field of food technologies uronic acids, as glucuronic, idouronic, hyaluronic were presented. The study showed, that nowadays the industry of products with their content is acquiring market traits, although it has insufficient scientific substantiation. Development segments with widely used uronate polysaccharides – pectins and alginates – according to the types of hydrogels (swollen hydrogel, cross-linked hydrogel, xerogel) were developed. The article presents examples and identified the required properties of substances intended for immobilization or encapsulation in the hydrogel matrix of uronate polysaccharides. The basic principles of uronate polysaccharides crosslinking chains in the hydrogel phase are determined. Possible methods of biologically active substances (BAS) retention in the matrix of uronate polysaccharides to reduce the risk of premature oxidation, destruction, decomposition, decomposition, evaporation were described. The search for information allowed us to identify key technological areas for the development of scientific research on the creation and use of HUP to improve people's lives and health. The archives of the world's leading publications in the field of food chemistry, biotechnology, food engineering, chemistry of new materials, food polymers and hydrocolloids were analyzed. The authors used in their work the resources of the Science Direct search system, which made it possible to determine the most promising and modern lines of development of HUP technologies and products based on them. The analysis of technologies has shown that existing innovative technologies are formed on “basic” technologies for producing solutions of high-molecular compounds under various conditions. Active modernization is carried out in the direction of creating products with immobilized biologically active substances, as well as in attempts to compose a composition with other polysaccharides and/or peptide components. The article notes that existing technologies allow developing other technologies with the help of which it is possible to expand the field of HUP application.Статья посвящена анализу состояния и динамике научных разработок в области создания продуктов для жизни и здоровья на основе гидрогелей из уронатных полисахаридов (ГУП). В статье отражены результаты мониторинга мировых научных исследований и их изменений в области технологий создания и применения ГУП. Авторы представили результаты ретроспективного анализа существующих технологий на основе малоизученых в области пищевых технологий уроновых кислот: глюкуроновая, идоуроновая, гиалуроновая. Исследование показало, что на сегодня индустрия продуктов с их содержанием приобретает вполне рыночные черты, хотя и имеет недостаточно полное научное обоснование. Сформированы сегменты разработок с широко используемыми уронатными полисахаридами - пектинами и альгинатами – по видам гидрогелей (гидрогель набухший, гидрогель сшитый, ксерогель). В статье представлены примеры и выявлены требуемые свойства веществ, предназначенных для иммобилизации или инкапсуляции в матрицу гидрогеля из уронатных полисахаридов. Определены основные принципы сшивания цепочек уронатных полисахаридов в фазе гидрогеля. Описаны возможные способы удержания биологически активных веществ (БАВ) в матрице уронатных полисахаридов для снижения риска преждевременного окисления, деструкции, разложения, распада, испарения. Поиск информации позволил определить ключевые технологические области развития научных исследований по созданию и применению ГУП для улучшения жизни и здоровья людей. Проанализированы архивы ведущих мировых изданий в области пищевой химии, биотехнологии, пищевой инженерии, химии новых материалов, пищевых полимеров и гидроколлоидов. Авторы использовали в работе ресурсы поисковой системы Science Direct, что позволило определить наиболее перспективные и современные направления развития технологий ГУП и продуктов на их основе. Анализ технологий показал, что существующие инновационные технологии сформированы на “базисных” технологиях получения растворов высокомолекулярных соединений при различных условиях. Активная модернизация проводится в направлении создания продуктов с иммобилизированными БАВ, а также в попытках составить композицию с другими полисахаридами и/или пептидными составляющими. В работе отмечается, что существующие технологии позволяют развивать другие технологии, с помощью которых возможно расширить сферы применения ГУП

АНАЛІЗ НЕСПРИЯТЛИВИХ ПОДІЙ ПІСЛЯ ІМУНІЗАЦІЇ ВАКЦИНАМИ ПРОТИ SARS CoV-2

Although the WHO-recommended coronavirus vaccines are safe and effective, vaccines provide new information to healthcare professionals about the extent and nature of adverse reactions to these drugs. The aim of the study is supplementing the available data on adverse reactions of vaccines on the example of the experience of vaccination of the teaching staff of the Cherkasy Medical Academy with vaccines COVISHIELD and COMIRNATY. Information for this study was collected retrospectively through a survey of 72 employees of the Cherkasy Medical Academy who were vaccinated with the COVISHIELD vaccine (first dose); 67 workers vaccinated with AstraZeneca (second dose); 54 workers who were vaccinated with COMIRNATY vaccine (first dose); 52 people vaccinated with this vaccine (second dose). The study confirmed that among the local side effects, the most common were pain at the injection site, among the systemic - fever, weakness, fatigue and drowsiness, headache, muscle pain, chills. Most of the side effects were most pronounced in young people, more often in women than in men.Although the WHO-recommended coronavirus vaccines are safe and effective, vaccines provide new information to healthcare professionals about the extent and nature of adverse reactions to these drugs. The aim of the study is supplementing the available data on adverse reactions of vaccines on the example of the experience of vaccination of the teaching staff of the Cherkasy Medical Academy with vaccines COVISHIELD and COMIRNATY. Information for this study was collected retrospectively through a survey of 72 employees of the Cherkasy Medical Academy who were vaccinated with the COVISHIELD vaccine (first dose); 67 workers vaccinated with AstraZeneca (second dose); 54 workers who were vaccinated with COMIRNATY vaccine (first dose); 52 people vaccinated with this vaccine (second dose). The study confirmed that among the local side effects, the most common were pain at the injection site, among the systemic - fever, weakness, fatigue and drowsiness, headache, muscle pain, chills. Most of the side effects were most pronounced in young people, more often in women than in men

Comparative Characteristics of Quality of Life of the Population in Modern Russia: Problems and Solutions

Analyzing the main socio-economic indicators of the standard of living of the population, the authors come to the conclusion about their minor changes for the period 2000–2017. To address the problems of the low-income strata of the Russian population, concrete measures are proposed, including reassessing the consumer basket, imposing restrictions on income levels, etc

Ecologically based sediment quality criteria of the oil content for freshwater ecosystems on example of Kuibishev water reservoir

This article presents the criteria of sediment quality assessment for oil content according the integrated approach which based on chemical, ecological and toxicological data derived from a TRIAD monitoring network. The ecological criteria (the lowest effect level and the severe effect level) were calculated for oil content in sediments of Kuibyshev water reservoir on the base of benthos taxa occurrence. For the toxicological data, the threshold effect level and probable effect level were calculated, based on the results of the toxicological acute pore water and solid phase tests. The sediment quality guideline (49 mg/kg) is as a consensus value of the lowest effect level and threshold effect level. Presented criteria can be used for ecological risk assessment for benthic community in condition of cruel oil contamination

Observation of an Excited Bc+ State

Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+π+π-. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date

Ethylene supports colonization of plant roots by the mutualistic fungus Piriformospora indica

The mutualistic basidiomycete Piriformospora indica colonizes roots of mono- and dicotyledonous plants, and thereby improves plant health and yield. Given the capability of P. indica to colonize a broad range of hosts, it must be anticipated that the fungus has evolved efficient strategies to overcome plant immunity and to establish a proper environment for nutrient acquisition and reproduction. Global gene expression studies in barley identified various ethylene synthesis and signaling components that were differentially regulated in P. indica-colonized roots. Based on these findings we examined the impact of ethylene in the symbiotic association. The data presented here suggest that P. indica induces ethylene synthesis in barley and Arabidopsis roots during colonization. Moreover, impaired ethylene signaling resulted in reduced root colonization, Arabidopsis mutants exhibiting constitutive ethylene signaling, -synthesis or ethylene-related defense were hyper-susceptible to P. indica. Our data suggest that ethylene signaling is required for symbiotic root colonization by P. indica