72 research outputs found

    Redox-regulated expression of glycolytic enzymes in resting and proliferating rat thymocytes

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    AbstractResting rat thymocytes partially degrade glucose aerobically to CO2 and H2O and produce reactive peroxide anions. In contrast proliferating cells, due to enhanced induction of glycolytic enzymes, degrade glucose almost completely to lactate thus minimizing the production of reactive oxygen species. In this paper we show that under conditions of oxidative stress the induction of the glycolytic enzymes in cultured rat thymocytes is markedly reduced. Furthermore, transfection assays with a rat hepatoma cell line and Drosophila Schneider cells revealed that reactive oxygen intermediates dramatically decrease the transcriptional activities of the Sp1-dependent aldolase A and pyruvate kinase M2 promoters leading to reduced reporter gene expression. These results indicate that cellular redox changes can regulate gene expression by reversible oxidative inactivation of Sp1 binding.© 1997 Federation of European Biochemical Societies

    Исследование путей повышения эксплуатационной надежности газопроводов проложенных в условиях многолетнемерзлых грунтов

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    Объектом исследования является магистральный газопровод, проложенный в условиях многолетнемерзлых грунтов. Цель работы – выявление технологических и технических параметров повышения конструктивной надежности магистрального газопровода проложенного в условиях распространения многолетнемерзлых грунтов. В работе проведет анализ нормативно-технической литературы по вопросам эксплуатации магистральных газопроводов в криолитозоне. Проведено исследование влияния негативных геокриологических процессов на газопровод. Произведено моделирование взаимодействия подземного газопровода с многолетнемерзлым грунтом и совершен анализ результатов. Диссертационная работа выполнена в текстовом редакторе Microsoft® Office Word 2013.The object of the study is the main gas pipeline laid in permafrost conditions. The purpose of the work is to identify technological and technical parameters for improving the structural reliability of the main gas pipeline laid in permafrost conditions. The work will analyze the normative and technical literature on the operation of main gas pipelines in the permafrost zone. The influence of negative geocryological processes on the gas pipeline has been studied. Simulation of the interaction of the underground gas pipeline with permafrost soil has been carried out and the analysis of the results has been completed. The dissertation work was done in the text editor Microsoft® Office Word 2013

    Использование цеолитов для очистки сточных вод от различных загрязнений

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    В данной статье проведен анализ результатов очистки вод от различных загрязнений природными и модифицированными цеолитами. Исследования показали, что природные цеолиты могут быть использованы с высокой эффективностью для очистки вод от гуминовых кислот, от аммиака при значении рН, близком к природным водам. Эффективность сорбции мышьяка на Fe-обменном цеолите достигает до 100 мг/кг. С увеличением площади удельной поверхности минерала увеличивается и степень сорбции мышьяка. Природные и модифицированные цеолиты используются для очистки сточных вод от ионов аммония и имеют высокую степень сорбции до 97 %.In this article water purification from various pollution by natural and modified zeolites is investigated. Studies have shown that natural zeolites have practical benefits: for the purification of water from humic acids, ammonia at pH closed to natural waters. Arsenic sorption on Feexchange zeolite reaches up to 100 mg/kg, as with an increase in the specific surface area increases and the degree of arsenic sorption. Natural and modified zeolites are used for wastewater treatment from ammonium and have a high degree of sorption up to 97%

    Identification of molecular candidates which regulate calcium-dependent CD8+ T-cell cytotoxicity

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    Cytotoxic CD8+ T lymphocytes (CTL) eliminate infected cells or transformed tumor cells by releasing perforincontaining cytotoxic granules at the immunological synapse. The secretion of such granules depends on Ca2+- influx through store operated Ca2+ channels, formed by STIM (stromal interaction molecule)-activated Orai proteins. Whereas molecular mechanisms of the secretion machinery are well understood, much less is known about the molecular machinery that regulates the efficiency of Ca2+-dependent target cell killing. CTL killing efficiency is of high interest considering the number of studies on CD8+ T lymphocytes modified for clinical use. Here, we isolated total RNA from primary human cells: natural killer (NK) cells, non-stimulated CD8+ T-cells, and from Staphylococcus aureus enterotoxin A (SEA) stimulated CD8+ T-cells (SEA-CTL) and conducted whole genome expression profiling by microarray experiments. Based on differential expression analysis of the transcriptome data and analysis of master regulator genes, we identified 31 candidates which potentially regulate Ca2+-homeostasis in CTL. To investigate a putative function of these candidates in CTL cytotoxicity, we transfected either SEA-stimulated CTL (SEA-CTL) or antigen specific CD8+ T-cell clones (CTL-MART-1) with siRNAs specific against the identified candidates and analyzed the killing capacity using a real-time killing assay. In addition, we complemented the analysis by studying the effect of inhibitory substances acting on the candidate proteins if available. Finally, to unmask their involvement in Ca2+ dependent cytotoxicity, candidates were also analyzed under Ca2+-limiting conditions. Overall, we identified four hits, CCR5 (C-C chemokine receptor type five), KCNN4 (potassium calcium-activated channel subfamily N), RCAN3 (regulator of calcineurin) and BCL (Bcell lymphoma) 2 which clearly affect the efficiency of Ca2+ dependent cytotoxicity in CTL-MART-1 cells, CCR5, BCL2, and KCNN4 in a positive manner, and RCAN3 in a negative way

    Interdependence of sequential cytotoxic T lymphocyte and natural killer cell cytotoxicity against melanoma cells

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    Cytotoxic T lymphocytes (CTL) and natural killer (NK) cells recognize and eliminate cancer cells. However, immune evasion, downregulation of immune function by the tumour microenvironment and resistance of cancer cells are major problems. Although CTL and NK cells are both important to eliminate cancer, most studies address them individually. We quantified sequential primary human CTL and NK cell cytotoxicity against the melanoma cell line SK-Mel-5. At high effector-to-target ratios, NK cells or melan-A (MART-1)-specific CTL eliminated all SK-Mel-5 cells within 24 h, indicating that SK-Mel-5 cells are not resistant initially. However, at lower effector-to-target ratios, which resemble numbers of the immune contexture in human cancer, a substantial number of SK-Mel-5 cells survived. Pre-exposure to CTL induced resistance in surviving SK-Mel-5 cells to subsequent CTL or NK cell cytotoxicity, and pre-exposure to NK cells induced resistance in surviving SK-Mel-5 cells to NK cells. Higher human leucocyte antigen class I expression or interleukin-6 levels were correlated with resistance to NK cells, whereas reduction in MART-1 antigen expression was correlated with reduced CTL cytotoxicity. The CTL cytotoxicity was rescued beyond control levels by exogenous MART-1 antigen. In contrast to the other three combinations, CTL cytotoxicity against SK-Mel-5 cells was enhanced following NK cell pre-exposure. Our assay allows quantification of sequential CTL and NK cell cytotoxicity and might guide strategies for efficient CTL–NK cell anti-melanoma therapies

    Исследование влияния жесткости конструкции на точность и качество деталей, полученных на установке гидроабразивной резки

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    Цель магистерской диссертации является исследование влияния жесткости конструкции на точность и качество деталей, полученных на установке гидроабразивной резки. В процессе исследования проводился ряд экспериментальных исследований по определению точности обработки в разных зонах резания при разных режимах, определена статистическая жёсткость системы гидроабразивной обработки. В результате исследования установлен характер погрешностей обработанных поверхностей деталей, получаемых при использовании технологии гидроабразивной резки, выявлены причины появления погрешностей обработки поверхностей деталей, оптимизированы параметры, влияющие на качество и точность обработки, получена математическая модель установки гидроабразивной обработки.The purpose of the master's thesis is to study the influence of structural rigidity on the accuracy and quality of parts obtained at the waterjet cutting plant. During the research, a number of experimental studies were conducted to determine the accuracy of processing in different cutting zones under different modes, and the statistical rigidity of the waterjet processing system was determined. The study of the nature of errors of machined part surfaces obtained by using water jet cutting technology, identified the causes of errors of processing of surfaces of details, the optimized parameters affecting the quality and accuracy of processing, a mathematical model of a hydroabrasive treatment

    Математичні основи визначення функціонального стану операторів складних технологічних об’єктів

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    Забезпечення високої надійності роботи оператора, а, відповідно, системи «людина – машина» (СЛМ), – є пріоритетним завданням для більшості сфер промисловості та сучасного виробництва. Тому важливим є розробка заходів по підвищенню кваліфікації операторів складних технологічних об’єктів (СТО), шляхом підбору математичного апарату для який б дав можливість підвищити надійність його діяльності в структурі СЛМ

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
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