Biochemical, histological and histochemical changes in Aristichthys nobilis Rich. liver exposed to thiamethoxam

Background and purpose: The aim of the present study was to investigate the effects of the insecticide thiamethoxam on some biochemical, histological and histochemical parameters of bighead carp liver (Aristichthys nobilis), which is an economically important fish species for aquaculture. Materials and methods: Different increasing concentrations of 6.6 mg l-1, 10 mg l-1 and 20 mg l-1 of the test chemical under laboratory conditions were tested for their toxicity on fish for 96. The hepatic activity of the enzymes lactate dehydrogenase (LDH), aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) were measured. In addition, the hepatic histological structure was observed for alterations, as well as the lipid content was observed by histochemical staining. Results: It was determined that the enzymatic activity of the exposed fish was increased compared to the control group (p<0.05). Furthermore, the enzymatic activity was increased proportionally to the increasing thiamethoxam concentrations. The histological lesions, which were observed in the liver parenchyma, were degenerative and necrotic. The degenerative alterations were as follows: granular, balloon and fatty degeneration. The necrotic alterations in the fish liver were associated with presence of karyopyknosis, karyorrehsis and karyolysis, respectively. The histological alterations in the liver blood vessels were hyperemia and lymphocyte proliferation. Along with the established histological changes in the liver parenchyma, we found presence of fatty degeneration in the hepatocytes using Sudan III staining on cryostat sections. Conclusions: Our study shows that there is a relation between the concentration of the insecticide and biochemical changes, as well the severity of expression of the histological and histochemical alterations in the bighead carp liver. Overall, such experiments could be successfully applied in research and monitoring programs to study the effects of pesticides on fish

Change detection of model organism’s (salmonella typhimurium ta 100) biological activity depending on the heavy metals’ content in soil

Здійснено біотестування ґрунтових зразків південного чорнозему степової зони Одеської області з використанням бактеріальної тест-системи Salmonella typhimurium TA 100. Порівняння результатів біотестування та хімічного аналізу ґрунтових зразків, результатів лабораторного експерименту та багатофакторного дисперсійного аналізу дозволило виявити приховані від класичних методів фактори, що викликають зміни генотоксичного потенціалу ґрунту, а також пояснити механізми виникнення кумулятивного ефекту при спільній дії суміші солей важких металів CoSO4 та FeSO4, CoSO4 та CuSO4. Осуществлено биотестирования почвенных образцов южного чернозема степной зоны Одесской области с использованием бактериальной тест-системы Salmonella typhimurium TA 100 Сравнение результатов биотестирования и химического анализа почвенных образцов, результатов лабораторного эксперимента и многофакторного дисперсионного анализа позволило выявить скрытые от классических методов факторы, вызывающие изменения генотоксического потенциала почвы, а также объяснить механизмы возникновения кумулятивного эффекта при совместном действии смеси солей тяжелых металлов CoSO4 и FeSO4, CoSO4 и CuSO4.The biotesting of south chernozem soil in Odessasteppe area was made with use of bacterial test-system Salmonella typhimurium TA 100. Comparison of results of biotesting and soil chemical analysis, results of laboratory experiment and multivariate analysis of variance allowed revealing the factors, which are usually hidden but generate genotoxicity potential of soil. Furthermore our research permitted to explain the mechanisms of cumulative effect occurrence under cooperative effect of heavy metals mixture of CoSO4 and FeSO4, CoSO4 and CuSO4.

Effective Power and Speed of Mining Dump Trucks in Fuel Economy Mode

Existing methods for determining the effective power, based on the calculation of the average indicator operation of the engine during the piston stroke, do not take into account the change in thermodynamic parameters and the polytropic operation of the engine, the value of which depends on the polytropic efficiency of the duty cycle. This is the reason that the calculation of the effective power leads to some error – the margin of the engine features. The identification of this stock allows us to review the entire line of dump trucks in the direction of increasing their pass- port effective capacity, which will lead to a reduction in capital purchase costs due to the choice of a previously un- derestimated and cheaper option, as well as a reduction in current operating costs due to a decrease in the specific fuel consumption rate. Taking into account the stochastic nature of the transport process and assessing the influence of all external and internal factors when calculating the rational mode of operation of a mining truck can further reduce specific fuel consumption by choosing the rational speed of its movement in loaded and empty directions

Linear magnetoresistance in compensated graphene bilayer

We report a nonsaturating linear magnetoresistance in charge-compensated bilayer graphene in a temperature range from 1.5 to 150 K. The observed linear magnetoresistance disappears away from charge neutrality ruling out the traditional explanation of the effect in terms of the classical random resistor network model. We show that experimental results qualitatively agree with a phenomenological two-fluid model taking into account electron-hole recombination and finite-size sample geometry

Субъективное благополучие студентов психолого-педагогических направлений в период эпидемии COVID-19

Introduction. With the development of humanistic attitudes in society, the importance of issues related to the subjective well-being of the individual increases. It is important not only how successful a person is at work or in educational activities, but also how well he/she feels. The COVID-19 pandemic has significantly changed the learning environment for university students. The study of the factors of subjective well-being of students expands the instrumental capabilities of psychological support during the pandemic. In the case of a repetition of a similar situation, this knowledge will be useful for helping students, and potentially a wider circle of people, to maintain subjective well-being. Aim. The present research aimed to investigate the subjective well-being of students of psychological and pedagogical directions of universities during the pandemic with an emphasis on its emotional component. Methodology and research methods. The research methodology is based on the subjective approach, which considers a student as an active subject, capable of successfully adapting to the changed conditions of an educational activity. In the course of the research, the authors identified the interrelationships of subjective well-being, its semantic markers and self-organisation to expand the possibilities of diagnosing subjective well-being and maintaining it during the periods of extreme social situations, as well as to use semantic markers for self-analysis. To assess subjective well-being, three methods were applied. Self-assessment of satisfaction with one's condition on a 10-point scale was carried out according to the following parameters: sleep, food, communication with family, communication with friends, studies, hobbies, and mood. The authors employed the scale of subjective well-being (by А. Perrudet-Badoux, G. Mendelsohn, J. Chiche, adapted by M. V. Sokolova) and psychosemantic characteristics of the subjective attitude to the situation of distance learning at the university due to the COVID-19 pandemic. To assess the ability of students to organise themselves in the changed learning conditions, the questionnaire of self-organisation of activities (N. T. Feather и M. J. Bond, adapted by E. Yu. Mandrikova) was used. The study involved 406 students between the ages of 18 and 45 years (383 women and 23 men) studying in the areas of psychology and pedagogy at the University of Tyumen and State Kurgan State University. For statistical analysis of the research data, the Mann-Whitney U Test and correlation analysis were used. Results. It was found that the ability to self-organise leads to higher subjective well-being, and this, in turn, stimulates self-organisation. Semantic markers of subjective well-being associated with educational activities during the pandemic, such as comfortable and uncomfortable, interesting and uninteresting, tired and vigorous, were highlighted. The authors revealed objective parameters associated with self-organisation and subjective well-being, namely sleep disturbances. This can lead to the fact that there is not enough daytime and the student works at night, thereby resulting in the disturbance of night sleep, and consequently - poor self-organisation. Scientific novelty._The parameters of subjective well-being and self-organisation of students in a new, extreme social situation, during the COVID-19 pandemic are considered. Practical significance._The data obtained can be used to develop a strategy for teaching students in a pandemic situation and forced self-isolation, as well as to increase subjective well-being in a new social situation. The research results can be applied in psychodiagnostics for a more complete interpretation of the parameters of subjective well-being, as well as for the use of the identified relationships in the programmes of psychological support for students of psychological and pedagogical specialities. Semantic markers of subjective well-being that have received empirical justification can be employed to create a diagnostic scale. © 2021 Russian State Vocational Pedagogical University. All rights reserved.Acknowledgements. The research was funded by the Russian Foundation for Basic Research (RFBR) and Tyumen Region within the research project № 20-413-720004

Ресурсный компонент цифровой образовательной среды в обучении студентов-лингвистов

Целью данного исследования является рассмотрение ресурсного компонента цифровой образовательной среды в контексте подготовки студентов-лингвистов. Для достижения поставленной цели была предпринята попытка разработать структуру цифровой образовательной среды для обучения будущих переводчиков, изучена методико-педагогическая и научная литература по данной проблеме, выделены основные цифровые ресурсы, которые могут использоваться при проектировании занятий.The purpose of this study is to consider the resource component of the digital learning environment in the context of the training of future linguists. To achieve this goal, an attempt was made to develop the structure of a digital learning environment for training future linguists, the methodological, pedagogical and scientific literature on this issue was studied, and the main digital resources that can be used in designing lessons were identified

Possibilities of Application of Modern Neurophysiological Methods in Diagnosis of Vibration Disease

Vibration disease is one of the leading in the structure of occupational diseases. A more detailed study of the pathogenesis, expanding the possibilities of diagnosis of vibration disease, is necessary. The aim of the study is to determine the diagnostic value of stabilometry, quantitative sensory testing and neuroenergocarting in vibration disease associated with the combined effects of local and general vibration. Materials and methods. Two groups of patients were examined: with the diagnosis of vibration disease associated with the combined effect of local and general vibration – 50 people (age 48.7 ± 3.1 years), not in contact with vibration – 30 people (age 49.1 ± 2.8 years). The study of the equilibrium function, the determination of the level of the constant potential of the brain by 12 standard leads and the determination of temperature and pain sensitivity. Statistical processing of the results was carried out using the software package “Statistica 6.0” (StatSoft Inc., USA). Differences were considered statistically significant at p &lt; 0.05. Results. In vibration disease, the vertical stance of patients is more unstable than in patients with no contact with vibration. In patients with vibration disease, there is a decrease in the threshold of cold sensitivity and an increase in the threshold of thermal sensitivity and thermal pain compared to the control group. According to our data, the increased level of permanent potential in patients with vibration disease is observed in the central (22.7 (12.6; 30.7) mV) and right central (20.4 (11.5; 27.1) mV), also the average level of permanent capacity in this group is increased – 17.1 (8.4; 25.8) mV.Conclusion. The results obtained indicate the involvement of the neurosensory complex united by single thalamic and cortical centers in the pathological process and confirm the diagnostic value of the methods used

Роль и перспективы развития стандартных образцов химического состава природных и техногенных сред в геоанализе

Emergence of requirements in the certified reference materials (CRMs) to perform chemical analysis of natural and man-made environments (geoanalysis); and formation of requirements to accuracy of results and quality management systems analysis are shown in the historical aspect. Creation of the multi-parameter CRMs of composition, size and quantity of mineral phases for geoanalysis are presented as new outlook.В историческом аспекте показаны причины появления потребности в стандартных образцах состава (СО) для выполнения химического анализа природных и техногенных сред (геоанализа); формирование требований к точности результатов и системам управления качеством анализа, в которых сформулированы алгоритмы применения СО. Отмечена перспективность создания для геоанализа многопараметрических СО состава, размеров и количества минеральных фаз