Mechanisms of Endothelial Dysfunction in Resistance Arteries from Patients with End-Stage Renal Disease

The study focuses on the mechanisms of endothelial dysfunction in the uremic milieu. Subcutaneous resistance arteries from 35 end-stage renal disease (ESRD) patients and 28 matched controls were studied ex-vivo. Basal and receptor-dependent effects of endothelium-derived factors, expression of endothelial NO synthase (eNOS), prerequisites for myoendothelial gap junctions (MEGJ), and associations between endothelium-dependent responses and plasma levels of endothelial dysfunction markers were assessed. The contribution of endothelium-derived hyperpolarizing factor (EDHF) to endothelium-dependent relaxation was impaired in uremic arteries after stimulation with bradykinin, but not acetylcholine, reflecting the agonist-specific differences. Diminished vasodilator influences of the endothelium on basal tone and enhanced plasma levels of asymmetrical dimethyl L-arginine (ADMA) suggest impairment in NO-mediated regulation of uremic arteries. eNOS expression and contribution of MEGJs to EDHF type responses were unaltered. Plasma levels of ADMA were negatively associated with endothelium-dependent responses in uremic arteries. Preserved responses of smooth muscle to pinacidil and NO-donor indicate alterations within the endothelium and tolerance of vasodilator mechanisms to the uremic retention products at the level of smooth muscle. We conclude that both EDHF and NO pathways that control resistance artery tone are impaired in the uremic milieu. For the first time, we validate the alterations in EDHF type responses linked to kinin receptors in ESRD patients. The association between plasma ADMA concentrations and endothelial function in uremic resistance vasculature may have diagnostic and future therapeutic implications

Technology platforms in Russia: a catalyst for connecting government, science, and business?

The article analyzes a new instrument of Russian innovation policy - technology platforms. The reasons for their establishment are outlined based on the analysis of the innovation system in Russia. Comparisons with the European Union technology platforms, which served as blueprints for developing similar structures in Russia, are provided. Russian platforms are found to suffer from the government micromanagement. More detailed analysis is provided through three case studies of selected technology platforms specializing in different representative economic areas. The results of these studies demonstrate that Russian technology platforms are still far from being effective communication instruments. The platforms received inadequate federal support at the initial stages of their development, which eventually affected their performance. Nevertheless, the first steps have been undertaken to create expert communities in important economic areas. The article suggests directions for further development of technology platforms, such as expanding a palette of stakeholders and conducting two-way monitoring - both of platforms' performance and government measures aimed at their development

Вязкоупругие и термодинамические свойства высоковязкой нефти различной степени обводненности

Dependencies of the viscoelastic and thermodynamic properties of high-viscosity oil from the oil-gathering reservoir of the N-Korenevskoye and Denisovskoye fields on the degree of water cut and temperature have been established. Under the conditions of shear deformations and at comparable temperatures, the nature of the processes of structure formation of oil at a low degree of water cut is due to phase transitions of paraffins, which is consistent with the experimental data described in the literature for non-watered oils, indicating the identity of the nature of intermolecular interactions between non-watered oil and oil with a low degree of water cut. The maximum effect of the thermal method for reducing the viscosity of oil with a low degree of water cut can be achieved when it is heated to the paraffin melting point Tm*, determined using the ln(η) = f (1/T) dependence. The peculiarity of the rheological behavior of high-water-cut oil is due to an increase in the energy of intermolecular interaction, which in the entire temperature range is practically comparable to Eact1 of low-water cut oil at T <Tm*, which is associated with the formationn of invert emulsions stabilized by interphase layers of asphaltene molecules. It is shown that an increase in temperature and shear deformations contribute to a decrease in the values of the effective viscosity of low and high water cut oil; however, the destruction of their colloidal structure does not occur in the entire range investigated. The loss of aggregate and kinetic stability of high-viscosity watered oil is achieved in the presence of a surfactant composition based on Sorbital C-20 and a sodium salt of alkylbenzenesulfonic acid, which causes the desorption of “natural stabilizers” from the oil-water interface and, as a consequence, the coalescence of water droplets.Установлены зависимости вязкоупругих и термодинамических свойств высоковязкой нефти из нефтесборного коллектора Н-Кореневского и Денисовского месторождений от степени обводненности и температуры. В условиях сдвиговых деформаций и при сопоставимых температурах характер процессов структурообразования нефти при низкой степени обводненности обусловлен фазовыми переходами парафинов, что согласуется с экспериментальными данными, описанными в литературе для необводненных нефтей, указывая на идентичность характера межмолекулярных взаимодействий необводненной нефти и нефти с низкой степенью обводненности. Максимальный эффект при термическом способе снижения вязкости нефти с низкой степенью обводненности можно достичь при ее нагреве до температуры плавления парафинов Тпл*, определенной с использованием зависимости ln(η) = f(1/T). Особенность реологического поведения высокообводненной нефти обусловлена ростом энергии межмолекулярного взаимодействия, которая во всем температурном интервале практически сопоставима с Еакт1 низкообводненной нефти при Т < Тпл*, что связано с образованием инвертных эмульсий, стабилизированных межфазными слоями из молекул асфальтенов. Показано, что снижению значений эффективной вязкости низко- и высокообводненной нефти способствует повышение температуры и сдвиговых деформаций, однако разрушения их коллоидной структуры во всем исследуемом интервале не происходит. Потеря агрегативной и кинетической устойчивости высоковязкой обводненной нефти достигается в присутствии поверхностно-активной композиции на основе Сорбиталь С-20 и натриевой соли алкилбензолсульфокислоты, вызывающей десорбцию «природных стабилизаторов» с межфазной границы раздела нефть–вода и, как следствие, коалесценцию капелек воды.

Marker assisted selection of potato breeding lines with combination of PVY resistance genes from different wild species

Potato virus Y (PVY) is considered as one of the most harmful virus infections of this crop. Thus, it is a topical problem to breed potato varieties resistant against a wide range of PVY strains and to create initial breeding material that will have a combination of resistance genes from different species. The aim of the study was: (1) to genotype a collection of 376 breeding lines (BL), developed from complex interspecific hybrids, using DNA markers of PVY resistance genes, (2) to identify accessions with markers of resistance genes from different species for subsequent use in marker assisted selection (MAS), (3) to evaluate the suitability of DNA markers of PVY resistance genes for genotyping BL developed through interspecific hybridization. It was ascertained that the markers most widely represented in the collection were RYSC3 of the Ryadg gene (49.7%), Ry364 and RAPD38-530 of the Rychc gene (50.5% and 45.2%, respectively), and Yes3-3A of the Rysto gene (29.8%). The markers Ry186 of Rychc and GP122/EcoRV780 of  Ryf-sto  were found only in some accessions. The frequency of occurrence of BL that had markers of PVY resistance genes from two different species varied between 2.7% (Yes3-3a marker of Rysto and both two markers of Rychc) and 8.5-9.0% (RYSC3 marker of Ryadg and both two markers of Rychc, or only Ry364 marker of this gene). In total, the collection was found to contain 134 BL (47.6%) with markers of resistance genes from two different species. A combination of four markers for three genes of different origin (Ryadg, Rysto and Rychc) was found in 27 BL (7.2%). Extreme resistance to PVY of most BL (302 out of 357) was obviously determined by the presence in them of the currently used resistance genes detected by DNA markers applied in the study. Nevertheless, a significant part of accessions (55 of 61) that did not have any markers was resistant to PVY. At the same time, 13 BL (3.5%) with the markers were susceptible to the virus. Such a level of discrepancies is considered as acceptable for the initial MAS of breeding material. The obtained data on the presence of the markers of PVY resistance genes of different origin and their combination in BL ensures a more effective use of such BL in breeding in comparison with the BL resistant to the virus, though lacking corresponding markers

The use of <i>in vitro</i> androgenesis for the involvement of interspecific hybrids between <i>Solanum tuberosum</i> L. and wild allotetraploid potato species <i>Solanum stoloniferum</i> Schltdl. et Bouché into breeding

Wild allotetraploid potato species Solanum stoloniferum Schltdl. &amp; Bouché from Mexico is regarded as a valuable source of resistance genes for use in breeding. However, introgression of its resistance genes into breeding material is hampered by a set of reproductive barriers. The genomic difference between S. stoloniferum (genome ААВВ) and S. tuberosum L. (AAAA) is one of them. This makes questionable the possibility of transferring a variety of valuable genes of the wild species localized on the chromosomes of its genome B into the genome of cultivated potatoes. It is proposed to produce tetraploid (4x, AAAB) interspecific hybrids of S. stoloniferum, which are regarded as more promising for homoeological recombination than pentaploid (5x, ААААВ) hybrids commonly used in the introgression schemes. However, the effective ploidy of tetraploid hybrids (3EBN) hinders their backcrossing to cultivated potatoes (4 EBN). For instance, our attempts to involve the tetraploid hybrid of S. stoloniferum IGC16/36.1 obtained by us into hybridization with potato varieties were unsuccessful for a number of years. To solve this problem, we suggested a technique based on the production of 4x plants obtained in anther culture of this hybrid. The present research was aimed at assessing the efficiency of this approach.Thirty-one plants were obtained in anther culture (androgenic clones, androclones) of the hybrid IGC16/36.1 in 2018. Most of them exceeded the initial hybrid in habitus strength and flowering intensity. As a result of crosses made in 2019, 1039 hybrid seeds were obtained from crossing 21 androclones with the ‘Lemhi Russet’ variety (8.7 seeds/pollination), 1017 seeds (7.5 seeds/pollination) from crosses of 23 androclones with the ‘Quarta’ variety, and 716 seeds (12.3 seeds/pollination) from crosses of 11 androclones and a diploid potato line IGC 17n8 capable of producing fertile unreduced (2n) pollen. The hybrid seeds had good germination rate of 70-90%. Among the androclones that gave progeny in crosses with potato varieties, we identified genotypes carrying DNA markers of late blight (LB) resistance genes Rpi-sto1, R2 and R3b, PVY resistance genes Ryadg, Rysto and Rychc, and potato wart disease resistance gene Sen2 (these markers were found in the initial accession of S. stoloniferum PI 205522 and in the IGC 16/36.1 hybrid). Despite the complex nature of inheritance of the analyzed markers in progenies of backcrosses of androclones, a number of isolated hybrids carried several markers, including those of the Rpi-sto1, a broad-spectrum gene for high resistance to late blight. Hybrids with relatively high tuber productivity, features of cultivated potatoes such as regularly shaped tubers with small eyes, and high field resistance to late blight were selected.The prospects for using androclones of the tetraploid interspecific hybrid IGC 16/36.1 for increasing the frequency of homoeologous A/B recombination of chromosomes are discussed

Реологические свойства и групповой химический состав окисленного битума в присутствии волокнистых материалов различной структуры

The rheological properties of oxidized bitumen in the presence of fibrous materials based on cellulose and chrysotile asbestos used as stabilizing additives in the production of crushed stone-mastic asphalt concrete mixtures have been studied. It has been established that the supramolecular structure of fibers characterizing the interaction between macromolecules largely determines the effectiveness of their structuring action for oxidized bitumen. Thus, the introduction of cellulose fiber leads to an increase in the ability of the bitumen colloidal structure to the simultaneous occurrence of elastic and plastic components of deformation. This is due to the uniform distribution of the fiber in the dispersion medium of bitumen due to the penetration of hydrocarbon components of bitumen into the interfibrillary space of cellulose and the rupture of hydrogen bonds between hydroxyl groups. Тhe presence of strong structural bonds between chrysotile-asbestos macromolecules prevents the formation of strong reinforcing mesh in bitumen oils. As a result, the values of the structural and rheological parameters Pk1, Pk2 and Pm of the bitumen/chrysotile-asbestos composition are 1.5–2 times lower compared to the values for the bitumen/cellulose composition. The results of the study of the group composition and structural-rheological properties of bitumen compositions after heating at T = 163 °C indicate a higher stability of the bitumen-cellulose structure to the processes of thermal oxidative degradation compared to the structure formed in the bitumen/chrysotile-asbestos composition. By the method of thin-layer chromatography, it was found that the concentration of oils in the bitumen/chrysotile-asbestos composition is higher as compared to the bitumen/cellulose composition, indicating that the weakening of rheological properties and thermal stability in the presence of chrysotile-asbestos is not related to the microstructure of its fibers, which, according to some researchers, is prone to selective diffusion of oils into the capillaries of fibrils. Изучены реологические свойства окисленного битума в присутствии волокнистых материалов на основе целлюлозы и хризотил-асбеста, используемых в качестве стабилизирующих добавок при производстве щебеночно-мастичных асфальтобетонных смесей. Установлено, что надмолекулярная структура волокон, характеризующая взаимодействие между макромолекулами, в значительной степени определяет эффективность их структурирующего действия для окисленного битума. Так, введение целлюлозного волокна приводит к повышению способности коллоидной структуры битума к одновременному возникновению упругой и пластической составляющих деформации, что обусловлено равномерным распределением волокна в дисперсионной среде битума вследствие проникновения углеводородных компонентов в межфибриллярное пространство целлюлозы и разрывам водородных связей между гидроксильными группами. В то же время наличие прочных структурных связей между макромолекулами хризотил-асбеста препятствует формированию прочной армирующей сетки в маслах битума и, как следствие, значения структурно-реологических параметров Pk1, Pk2 и Pm композиции битум–хризотил-асбест в 1,5–2 раза ниже по сравнению со значениями для композиции битум/целлюлоза. Результаты исследования группового состава и структурно-реологических свойств битумных композиций после прогрева при Т = 163 °С свидетельствуют о более высокой стабильности битумно-целлюлозной структуры к процессам термоокислительной деструкции по сравнению со структурой, сформированной в присутствии хризотил-асбеста. Методом тонкослойной хроматографии установлено, что концентрация масел в композиции битум–хризотил-асбест выше по сравнению с композицией битум–целлюлоза, свидетельствуя о том, что ослабление реологических свойств и термостабильности в присутствии хризотил-асбеста не связано с особенностями микроструктуры его волокон, склонной, по мнению ряда исследователей, к избирательной диффузии масел в капилляры фибрилл.

Влияние химического строения катионных ПАВ на процессы смачивания породообразующих минералов

Interfacial interactions of cationic surfactants of various chemical structures at the solution / finely dispersed mineral material (quartz and dolomite) interface were studied. It is established that the modification of the surfaces of quartz and dolomite with cationic surfactants leads to a change in the structure and radius of the capillaries due to the formation of adsorption-solvate shells. The hydrophobic ability of cationic surfactants is determined by the structure of the hydrophilic part of their molecules – the balance of amino groups in the alkyl chains and the absence of steric hindrances during adsorption interaction with the surface of mineral materials. The mixture of surfactants containing six amino groups and a polyhydric alcohol glycerin has an effective hydrophobic ability from both aqueous and highly mineralized solutions.Изучены межфазные взаимодействия катионных ПАВ различного химического строения на границе раздела раствор/тонкодисперсный минеральный материал (кварц и доломит). Установлено, что модифицирование поверхностей кварца и доломита катионными ПАВ приводит к изменению структуры и радиуса капилляров вследствие образования адсорбционно-сольватных оболочек. Гидрофобизирующая способность катионных ПАВ определяется строением гидрофильной части их молекул – сбалансированностью аминогрупп в алкильных цепях и отсутствием стерических затруднений при адсорбционном взаимодействии с поверхностью минеральных материалов. Эффективной гидрофобизирующей способностью как из водных, так и высокоминерализованных растворов обладает композиция из аминопроизводных жирных кислот рапсового масла, содержащая шесть аминогрупп и многоатомный спирт глицерин

Регулирование межфазных процессов поверхностно-активными веществами и их композициями при разработке технологий нефтеотдачи

Physicochemical aspects of the regulation of interfacial processes occurring at the oil-water-rock interface in the presence of ionic surfactants and their compositions are considered with the goal of developing efficient, scientifically grounded innovative technologies ensuring enhanced oil recovery and refining. A complex of studies of surface phenomena in the presence of ionic surfactants made it possible to identify criteria for evaluating the effectiveness of their action at the oil-water-rock interface, which makes it possible to predict the behavior of surfactants in real conditions of oil production and to use them purposefully in various enhanced oil recovery technologies.Рассмотрены физико-химические аспекты регулирования межфазных процессов, протекающих на границах раздела нефть–вода–порода в присутствии ионогенных ПАВ и их композиций, с целью разработки эффективных, научно обоснованных инновационных технологий, обеспечивающих повышение нефтеотдачи и нефтепереработки. Проведенный комплекс исследований поверхностных явлений в присутствии ионогенных ПАВ позволил выявить критерии оценки эффективности их действия на границах раздела нефть–вода–порода, что дает возможность прогнозировать поведение ПАВ в реальных условиях нефтедобычи и целенаправленно использовать их в различных технологиях повышения нефтеотдачи

ВЛИЯНИЕ ЭЛЕКТРОННОГО ОБЛУЧЕНИЯ НА ЭЛЕКТРИЧЕСКИЕ ХАРАКТЕРИСТИКИ p-n-СТРУКТУР НА ЯДЕРНО-ЛЕГИРОВАННОМ КРЕМНИИ

The article studies the effect of electron radiation with energy of 4 MeV on the characteristics of high-voltage (4.5 kV) silicon diode p-n-structures based on nuclear-doped silicon. During the research the dose dependences of the correlations between the static and dynamic characteristics of the p-n structures were built, and the radiation damage coefficient of minority carrier lifetime Kτ was determined. Using the DLTS-spectroscopy method, the formation in the band-gap of basic n-Si of six energy levels of radiation defects affecting the characteristics of irradiated p-n-structures was determined. В работе проведены исследования влияния электронного облучения с энергией 4 МэВ на характеристики высоковольтных (до 4,5 кВ) диодных кремниевых p-n-структур, изготовленных на ядерно-легированном кремнии. Получены дозовые зависимости статических и динамических характеристик p-n-структур, определен коэффициент радиационных повреждений времени жизни неосновных носителей заряда Kτ . С помощью метода DLTS-спектроскопии определено образование в запрещенной зоне базового n-Si шести энергетических уровней радиационных дефектов, влияющих на характеристики облученных p-n-структур.