35 research outputs found

    Phase Structure in a Hadronic Chiral Model

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    We study the phase diagram of a hadronic chiral flavor-SU(3) model. Heavy baryon resonances can induce a phase structure that matches current results from lattice-QCD calculations at finite temperature and baryon density. Furthermore, we determine trajectories of constant entropy per net baryon in the phase diagram.Comment: 4 pages, 5 figure

    Surface modification of steel inductor as an approach to enchance its durability in high pulsed magnetic fields

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    The work concerns both a theoretical analysis of magnetic and thermal effects in conductor with inhomogeneous initial conductivity and realization of this approach on steel, oriented on inductors production, by steel surface modification. Monotonically changing spe-cific resistance of steel was suggested to be realized via steel pack chromizing.This work was performed as part of state task No. 0389-2015-0025 and supported in part by RAS Program Project No.18-2-2-8

    The activity of matrix metalloproteinases and the concentration of their tissue inhibitors in the blood serum of patients with type 2 diabetes mellitus, depending on the stage of compensation of the disease

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    The aim of the study was to test the hypothesis on the possible reason for the decrease in the activity of matrix metalloproteinases (MMPs) as a consequence of the high concentration of their tissue inhibitors (TIMPs) in the blood serum of patients with type 2 diabetes mellitus (T2DM). Material and methods. In the experimental part of the article, we used the blood serum of patients under observation in the clinic of the Federal Research Center of Fundamental and Translational Medicine. According to the content of glycated hemoglobin (HbA1С) in blood serum, the patients were divided into 3 groups: at the stage of compensation (6.0–6.5 % HbA1С), at the stage of subcompensation (6.6–7.0 % HbA 1С) and decompensation (> 7.0 % HbA1С). The activity of MMPs 2 and 7 in blood serum samples was measured by a fluorimetric method using a fluorescent substrate specific for these MMPs. The concentration of TIMP-1 (inhibitor of all non-membrane-bound MMPs) and TIMP-2 (active against MMP-2 and -7) in blood serum were determined by enzyme immunoassay. Results and discussion. In patients with T2DM, the MMP-2 and -7 activities decreased, more pronouncedly at the stage of decompensation. An increase in the concentration of TIMP-1 was observed in the serum of all patients, while no significant changes in the content of TIMP-2 were found. At the stage of decompensation, a decrease in MMP activity was accompanied by a decrease in the content of insulin, C-peptide and a corresponding increase in the level of proinsulin. An inverse correlation was found between the concentrations of TIMP-1 and insulin in patients at the stage of decompensation of T2DM. It is assumed that the activity of MMP-2 and -7, in comparison with their inhibitors, forms stronger correlations with the parameters of carbohydrate metabolism

    Strangeness and light fragment production at high baryon density

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    We discuss medium effects on light cluster production in the QCD phase diagram within a generalized Beth-Uhlenbeck (GBU) approach by relating Mott transition lines to those for chemical freeze-out. We find that in heavy-ion collisions at highest energies provided by the LHC light cluster abundances should follow the statistical model because of low baryon densities. At low energies in the nuclear fragmentation region, where the freeze-out interferes with the liquid-gas phase transition, selfenergy and Pauli blocking effects are important. At intermediate energies the HADES, FAIR and NICA experiments can give new information. The GBU approach provides new insights to strange hadron production in this energy domain for explaining the "horn" effects.Comment: 8 pages, 5 figures, Contribution to the Proceedings of the 18th International Conference on 'Strangeness in Quark Matter' (SQM-2019), Bari, Italy, 10-15 June, 201

    Evolution of Baryon-Free Matter Produced in Relativistic Heavy-Ion Collisions

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    A 3-fluid hydrodynamic model is introduced for simulating heavy-ion collisions at incident energies between few and about 200 AGeV. In addition to the two baryon-rich fluids of 2-fluid models, the new model incorporates a third, baryon-free (i.e. with zero net baryonic charge) fluid which is created in the mid-rapidity region. Its evolution is delayed due to a formation time τ\tau, during which the baryon-free fluid neither thermalizes nor interacts with the baryon-rich fluids. After formation it thermalizes and starts to interact with the baryon-rich fluids. It is found that for τ\tau=0 the interaction strongly affects the baryon-free fluid. However, at reasonable finite formation time, τ\tau=1 fm/c, the effect of this interaction turns out to be substantially reduced although still noticeable. Baryonic observables are only slightly affected by the interaction with the baryon-free fluid.Comment: 17 pages, 3 figures, submitted to the issue of Phys. of Atomic Nuclei dedicated to S.T. Belyaev on the occasion of his 80th birthday, typos correcte

    Apolipoprotein A-I increases the activity of lysosomal glycosidases in the liver of mice with BCG-induced tuberculosis inflammation

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    This work shows the ability of apolipoprotein A-I to influence the activity of lysosomal glycosidases in the liver of mice in a model of BCG-induced tuberculous inflammation. The aim of the investigation was to study the activity of lysosomal glycosidases in the liver of mice using a model of BCG-induced tuberculous inflammation after intravenous administration of apolipoprotein A-I. Material and methods. The studies were performed on male CBA mice weighing 20-22 g. Disseminated tuberculous inflammation was modeled by a single intraperitoneal injection of 0.5 mg of BCG vaccine. The activity of lysosomal glycosidases was assessed spectrofluorimetrically by the content of hydrolysis products of the corresponding fluorogenic substrates. Results. Tuberculous inflammation led to a pronounced decrease in the activity of lysosomal glycosidases in the liver. Thus, β-galactosidase was decreased 2.3 times, β-glucosidase – 2.8 times, β-glucuronidase – 2.5 times compared with healthy animals. Intravenous injection of apolipoprotein A-I to animals against the background of BCG infection prevented a significant decrease in the enzymatic activity of glycosidases and these values practically did not differ from the control values. Conclusions. Enzymatic activity of lysosomal glycosidases in the group of mice with intravenous administration of apolipoprotein A-I against the background of BCG infection was 1.5–2 times higher than the corresponding indicators in the group of animals with BCG-infection without administration of apolipoprotein A-I, i.e. without treatment

    Catalytic Reactions in Heavy-ion Collisions

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    We discuss a new type of reactions of a phi meson production on hyperons, pi Y--> phi Y and anti-kaons bar-K N --> phi Y. These reactions are not suppressed according to Okubo-Zweig-Iizuka rule and can be a new efficient source of phi mesons in a nucleus-nucleus collision. We discuss how these reactions can affect the centrality dependence and the rapidity distributions of the phi yield.Comment: talk at 6th International Workshop on Critical Point and Onset of Deconfinment (CPOD2010), Dubna, August 22-28, 201

    On freeze-out problem in relativistic hydrodynamics

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    A finite unbound system which is equilibrium in one reference frame is in general nonequilibrium in another frame. This is a consequence of the relative character of the time synchronization in the relativistic physics. This puzzle was a prime motivation of the Cooper--Frye approach to the freeze-out in relativistic hydrodynamics. Solution of the puzzle reveals that the Cooper--Frye recipe is far not a unique phenomenological method that meets requirements of energy-momentum conservation. Alternative freeze-out recipes are considered and discussed.Comment: 6 pages, 2 figures, references are corrected and updated, to be published in the issue of Phys. Atom. Nucl. dedicated to S.T. Belyaev on the occasion of his birthda

    Role of biomarkers of myocardial injury and inflammation in predicting ischemia-reperfusion injury in patients with ST-segment elevation acute coronary syndrome undergoing endovascular revascularization

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    Aim. To evaluate the informative value of biomarkers (cardiac troponin l (cTnl), high-sensitivity C-reactive protein (hsCRP), N-terminal pro-brain natriuretic peptide (NTproBNP), stimulating growth factor (ST2)) as laboratory markers of myocardial ischemia-reperfusion injury in patients with ST-segment elevation acute coronary syndrome (STEACS) undergoing endovascular revascularization.Material and methods. The study included 115 patients with STEACS who underwent endovascular myocardial revascularization. To identify the informative value of biomarkers, the levels of cTnl, NTproBNP, hsCRP, sST2 were analyzed at baseline, as well as after reperfusion therapy on the 2nd (cTnl) and 5th (sST2, hsCRP, NTproBNP) days. Contrast-enhanced cardiac magnetic resonance imaging was performed 5 days after endovascular intervention.Results. Microvascular obstruction was detected in 54 patients (47%), of which 24 (44%) patients had a combination of microvascular obstruction and myocardial hemorrhage. ln 61 cases (53%), no microvascular damage was registered. lt was found that with an increase in the threshold initial NTproBNP levels >590 pg/ml, the odds ratio (OR) of myocardial reperfusion injury was 12,2 (95% confidence interval (CI), 4,81-30,92, p<0,001). In addition, we analyzed biomarker levels in the early period after myocardial infarction, at which threshold values of reperfusion injury parameters were established as follows: for cTnI >8,1 ng/ml, OR=7,17 (95% CI, 3,11-16,53, p=0,001); for hsCRP >14 mg/L, OR=12,71 (95% CI, 5,03-32,08, p=0,001); for NTproBNP >334 pg/ml, OR=11,8 (95% CI, 4,88-28,59, p=0,001); for sST2 >41 ng/ml, OR=7,17 (95% CI, 3,11-16,53, p=0,001). According to multivariate analysis, predictors of microvascular injury were the initial NTproBNP values, as well as the cTnI, hsCRP, and sST2 values in the early postinfarction period (sensitivity — 89,5%, specificity — 83,3%).Conclusion. Thus, the initial NTproBNP, as well as cTnI, hsCRP, sST2 values after percutaneous coronary intervention are more informative for assessing the risk of microvascular damage
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