875 research outputs found

    Electrophoretic deposition of YSZ layers on pyrolytic graphite and a porous anode substrate based on NiO-YSZ

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    Solid oxide fuel cells are promising hydrogen energy devices. The goal of this research was to create ceramic layers for SOFCs based on yttria-stabilized zirconia (YSZ) and to investigate their parameters. YSZ ceramic layers with a thickness of 5.14 μm on a porous NiO–YSZ substrate and 7 μm on pyrolytic graphite were obtained by electrophoretic deposition. X-ray diffraction and electron microscopy were used to determine the composition, structure, and morphological features of ceramic layers. The effects of the substrate's nature, the degree of dispersion of the initial YSZ powder, and the heat treatment conditions on the properties of the ceramic layer YSZ were considered

    Study to elucidate the pharmacological activity of retinalamin in a rat model of ischemic retinopathy

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    Over the past few years, the incidence of retinal ischemic disorders has been increasing, due to a rising prevalence of such socially burdensome diseases as diabetes and hypertension, which ultimately lead to ocular vascular pathology. The identification of new treatment options that would prevent retinal neuron death is a crucial task of modern pharmacolog

    On Nonperturbative Calculations in Quantum Electrodynamics

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    A new approach to nonperturbative calculations in quantum electrodynamics is proposed. The approach is based on a regular iteration scheme for solution of Schwinger-Dyson equations for generating functional of Green functions. The approach allows one to take into account the gauge invariance conditions (Ward identities) and to perform the renormalization program. The iteration scheme can be realized in two versions. The first one ("perturbative vacuum") corresponds to chain summation in the diagram language. In this version in four-dimensional theory the non-physical singularity (Landau pole) arises which leads to the triviality of the renormalized theory. The second version ("nonperturbative vacuum") corresponds to ladder summation and permits one to make non-perturbative calculations of physical quantities in spite of the triviality problem. For chiral-symmetrical leading approximation two terms of the expansion of the first-step vertex function over photon momentum are calculated. A formula for anomalous magnetic moment is obtained. A problem of dynamical chiral symmetry breaking (DCSB) is considered, the calculations are performed for renormalized theory in Minkowsky space. In the strong coupling region DCSB-solutions arise. For the renormalized theory a DCSB-solution is also possible in the weak coupling region but with a subsidiary condition on the value of α\alpha.Comment: 31 pages, Plain LaTex, no figures. Journal version: some discussion and refs. are adde

    Features of the intestinal microbiome in patients with thyroid diseases

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    Introduction. Today the search and development of new methods for diagnosing organic or functional pathology of the thyroid gland with an asymptomatic or clinically nonspecific course is an urgent task of endocrinology and therapy. The functioning of the thyroid gland and the state of the human intestinal microbiome are dynamically interrelated. One of the considered promising methods is mass spectrometry of microbial markers of the human intestinal microbiota.The purpose of the study. To study the microbial spectrum and characteristics of the biotic environment of the intestine in patients with thyroid diseases.Materials and methods. 21 patients were examined (8 men and 13 women, median age 40.5 [31.75; 54] years, respectively; 15 with thyroid disease, 6 without thyroid disease). In addition to the standard clinical and laboratory-instrumental examination, patients, colon contents were examined by chromatography-mass spectrometry of microbial materials. The work used descriptive non-parametric statistics with subsequent interpretation. Mean values of indicators and their variance are presented as median, upper and lower quartiles. In relation to representatives of the fecal microbiota, in addition to absolute values, the frequency of occurrence of the microorganism within the reference range, moderate or pronounced deviations was taken into account. The determination of the statistical significance of differences in the relative frequency value was carried out using Fisher’s exact test. The presentation of the results is implemented in the form of range diagrams, compactly depicting a one-dimensional probability distribution, tables. Results. Differences in the composition of the microbiota of the control group and the experimental group for Alcaligenes spp., Staphylococcus spp., Megamonas hypermegale, Peptostreptococcus anaerobius were revealed.Conclusions. The development of thyroid gland pathology is accompanied by significant deviations in the composition of the fecal microbiota, determined by mass spectrometry of microbial markers. In persons with thyroid pathology, in the absence of clinically significant external influences on the intestinal microbiome, a pronounced decrease in the level of Alcaligenes spp., Staphylococcus spp., is detected, a tendency to a decrease in the level of Megamonas hypermegale, Peptostreptococcus anaerobius is determined. Further differentiated study of the composition of the intestinal microbiome in patients with thyroid diseases is required, depending on the nosological affiliation and the nature of the endocrine dysfunction

    Features of information dissemination in the visual sensory system depending on the processes of visual perception

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    The goal of the research is to study the features of visual information distribution depending on the pole of cognitive style: field-dependence/ field-independence (FD/ FID

    On the roots of the Poincare structure of asymptotically flat spacetimes

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    The analysis of vacuum general relativity by R. Beig and N. O Murchadha (Ann. Phys. vol 174, 463 (1987)) is extended in numerous ways. The weakest possible power-type fall-off conditions for the energy-momentum tensor, the metric, the extrinsic curvature, the lapse and the shift are determined, which, together with the parity conditions, are preserved by the energy-momentum conservation and the evolution equations. The algebra of the asymptotic Killing vectors, defined with respect to a foliation of the spacetime, is shown to be the Lorentz Lie algebra for slow fall-off of the metric, but it is the Poincare algebra for 1/r or faster fall-off. It is shown that the applicability of the symplectic formalism already requires the 1/r (or faster) fall-off of the metric. The connection between the Poisson algebra of the Beig-O Murchadha Hamiltonians and the asymptotic Killing vectors is clarified. The value H[K^a] of their Hamiltonian is shown to be conserved in time if K^a is an asymptotic Killing vector defined with respect to the constant time slices. The angular momentum and centre-of-mass, defined by the value of H[K^a] for asymptotic rotation-boost Killing vectors K^a, are shown to be finite only for 1/r or faster fall-off of the metric. Our center-of-mass expression is the difference of that of Beig and O Murchadha and the spatial momentum times the coordinate time. The spatial angular momentum and this centre-of-mass form a Lorentz tensor, which transforms in the correct way under Poincare transformations.Comment: 34 pages, plain TEX, misleading notations changed, discussion improved and corrected, appearing in Class. Quantum Gra

    USp(2k) Matrix Model: Nonperturbative Approach to Orientifolds

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    We discuss theoretical implications of the large k USp(2k) matrix model in zero dimension. The model appears as the matrix model of type IIB superstrings on a large T6/Z2T^{6}/Z^{2} orientifold via the matrix twist operation. In the small volume limit, the model behaves four dimensional and its T dual is six-dimensional worldvolume theory of type I superstrings in ten spacetime dimensions. Several theoretical considerations including the analysis on planar diagrams, the commutativity of the projectors with supersymmetries and the cancellation of gauge anomalies are given, providing us with the rationales for the choice of the Lie algebra and the field content. A few classical solutions are constructed which correspond to Dirichlet p-branes and some fluctuations are evaluated. The particular scaling limit with matrix T duality transformation is discussed which derives the F theory compactification on an elliptic fibered K3.Comment: LaTeX, 29 pages, 3 figures. PostScript problems are fixe

    Дослідження синдрому емоційного і професійного вигорання у фармацетичних працівників

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    The burnout as a result of professional stress occurs when the adaptive capacity (resources) of the pharmaceutical worker in overcoming stressful situation becomes difficult, the "emotional burnout syndrome" - is the appropriate response to prolonged working stresses of employee during his professional activity. Our conducted researches in the regions of the country show that only 3-5% of pharmaceutical professionals familiar with the term "emotional burnout syndrome". So inKievto 10 per cent of people are familiar with this concept, at the same time, 54 per cent of workers aged 45-60 years old and 32 per cent aged 25-30 years old every day get into stressful situations and have different diseases, indicating the presence of the syndrome "professional burnout".Выгорание как следствие профессиональных стрессов возникает тогда, когда адаптационные возможности (ресурсы) фармацевтического работника в преодолении стрессовой ситуации становятся затруднительными, т.е. "синдром эмоционального выгорания" – это соответствующая реакция на продолжительные рабочие стрессы работника, в процессе его профессиональной деятельности. Проведенные собственные исследования в областях страны свидетельствуют, что только 3-5%  фармацевтических работников знакомы с понятием "синдром эмоционального выгорания". Так в  г. Киеве до 10% человек ознакомленным с этим понятием, в то же время 54% работников в возрасте 45-60 лет и 32% в возрасте 25-30 лет ежедневно попадают в стрессовые ситуации и имеют различные заболевания, свидетельствующие о наличии синдрома "профессионального выгорания".Вигорання як наслідок професійних стресів виникає тоді, коли адаптаційні можливості (ресурси) фармацевтичного працівника у подоланні стресової ситуації стають скрутними, тобто "синдром емоційного вигорання" - це відповідна реакція на тривалі робочі стреси працівника, в процесі його професійної діяльності. Проведені власні дослідження в регіонах країни свідчать, що тільки 3-5% фармацевтичних працівників знайомі з поняттям "синдром емоційного вигорання". Так у м. Києві до 10% осіб  ознайомлені з цим поняттям, в той же час 54% працівників у віці 45-60 років і 32% у віці 25-30 років щодня потрапляють в стресові ситуації і мають різні захворювання, що свідчать про наявність синдрому "професійного вигорання"

    Prevalence of professional burnout among practicing cardiologists in the constituent entities of the Russian Federation

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    The burnout syndrome among healthcare professionals is a headline problem in the world, as it leads to poor health of medical workers, affects patient satisfaction with health care and the healthcare system as a whole. At the same time, existing preventive measures can improve the well-being of staff.Aim. To study the prevalence of professional burnout syndrome among practicing cardiologists in the Russian Federation (RF).Material and methods. This cross-sectional study was carried out using the method of online anonymous surveying. The inclusion criterion was the current practical activity in the RF. The study involved 452 cardiologists from 8 federal districts (women; n=377, 83,4%), 48,2% of which worked in a hospital. Occupational burnout was assessed using the Maslach Burnout Inventory (MBI) questionnaire in the Russian language adaptation for healthcare workers by N. E. Vodopyanova and E. S. Starchenkova. The score was calculated on three subscales (emotional exhaustion, depersonalization, personal accomplishment), the maximum score for the subscales was 54, 30 and 48, respectively. The personal accomplishment subscale is the opposite as follows: the higher the score, the less the symptom severity. Additionally, demographic parameters, working conditions, the desire to change job and field of activity were taken into account. Regression analysis was used to establish associations of burnout with factors.Results. The median score of the emotional exhaustion subscale was 29,5 (23,0; 35,0) points, depersonalization — 12,0 (8,0; 16,0) and personal accomplishment — 32,0 (28,0; 37,0). Men had higher depersonalization score than women as follows: 15,0 (10,0; 18,0) vs 11,0 (8,0; 15,0), p=0,001. High degrees of emotional exhaustion and depersonalization (burnout) were found in 235 (52%) cardiologists, while all three symptoms simultaneously — in 132 (29,2%) doctors. There were no symptoms of burnout in 84 (18,6%) cardiologists. A high degree of burnout was associated with a desire to change job (p<0,001).Conclusion. A high prevalence of professional burnout among practicing cardiologists in the RF was revealed, which, in turn, is associated with the desire to change job or occupation
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