248 research outputs found
Laser spectoscopy of Mandelstems - Brillian scattering in aqueous nonelectrolyte solutions
In this work we developed a method of laser spectroscopy to study the frequency shift of Mandelshtam-Brillouin components in the fine structure of Reyleigh line, which are origin due to the pressure fluctuations. The method allows to study a character of hypersound (~109 Hz)propagation in a critical region of a thermodynamic instability. Analysis of a complex of experimental material , presented in the paper, allows one to conclude that in aqueous solutions of non-electrolytes at critical concentration there is a whole structural transformations in solutions at the singular point temperature in âtemperature-concentrationâ coordinate
Oxygen-glucose deprivation induces ATP release via maxi-anion channels in astrocytes
ATP represents a major gliotransmitter that serves as a signaling molecule for the cross talk between glial and neuronal cells. ATP has been shown to be released by astrocytes in response to a number of stimuli under nonischemic conditions. In this study, using a luciferin-luciferase assay, we found that mouse astrocytes in primary culture also exhibit massive release of ATP in response to ischemic stress mimicked by oxygen-glucose deprivation (OGD). Using a biosensor technique, the local ATP concentration at the surface of single astrocytes was found to increase to around 4Â ÎŒM. The OGD-induced ATP release was inhibited by Gd3+ and arachidonic acid but not by blockers of volume-sensitive outwardly rectifying Clâ channels, cystic fibrosis transmembrane conductance regulator (CFTR), multidrug resistance-related protein (MRP), connexin or pannexin hemichannels, P2X7 receptors, and exocytotic vesicular transport. In cell-attached patches on single astrocytes, OGD caused activation of maxi-anion channels that were sensitive to Gd3+ and arachidonic acid. The channel was found to be permeable to ATP4â with a permeability ratio of PATP/PClâ=â0.11. Thus, it is concluded that ischemic stress induces ATP release from astrocytes and that the maxi-anion channel may serve as a major ATP-releasing pathway under ischemic conditions
The relationship of cytokine status with left ventricular hypertrophy in patients with arterial hypertension
Aim. To study the relationship of tumor necrosis factor α and interleukin-10 levels with the presence of left ventricular hypertrophy and myocardial remodeling in patients with arterial hypertension.
Metods. 156 patients with hypertension aged 40 to 75 years (mean age 55.8±7.5 years), including 57 women and 99 men were examined. All patients were divided into two groups. Group 1 included 83 patients without left ventricular hypertrophy (55.5±7.5 years), group 2 included 73 patients with left ventricular hypertrophy (56.2±7.8 years), established by echocardiographic signs. All patients in addition to the general clinical examination and biochemical studies had echocardiography and Doppler echocardiography performed, as well as measurement of the concentration of tumor necrosis factor α and interleukin-10 by solid-phase enzyme immunoassay using specialized «Cytokine-Stimulus-Best» kit (Novosibirsk, Russia).
Results. The concentration of tumor necrosis factor α in patients without left ventricular hypertrophy was 8.43±1.36 pg/ml and was comparable with the concentration of this cytokine in patients with left ventricular hypertrophy (8.54±1.58 pg/ml, p >0.05). This pattern was typical for both men and women. The concentration of interleukin-10 in both groups was also comparable (15.4±3.6 pg/ml in group 1 and 14.7±3.4 pg/ml in group 2, p >0.05). However, we identified gender-specific features in the relationship of interleukin-10 with the presence of left ventricular hypertrophy in patients with hypertension. Thus, while in women the concentration of cytokine in groups with/without left ventricular hypertrophy did not differ significantly, in men without hypertrophy the level of interleukin-10 of 15.7±3.6 pg/ml, was significantly higher than the value of the same indicator in the group of men with left ventricular hypertrophy (14.8±2.9 pg/ml, p <0.025). Multivariate regression analysis showed that tumor necrosis factor α and interleukin-10 concentrations correlated to left ventricular wall thickness in patients without left ventricular hypertrophy. No such pattern was revealed for patients with hypertrophy.
Conclusion. The results demonstrate the modulating role of tumor necrosis factor α and interleukin-10 in myocardial remodeling processes in arterial hypertension
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Superfluid helium testing of a stainless steel to titanium piping transition joint
Stainless steel-to-titanium bimetallic transitions have been fabricated with an explosively bonded joint. This novel joining technique was conducted by the Russian Federal Nuclear Center, working under contract for the Joint Institute for Nuclear Research. These bimetallic transitions are being considered for use in future superconducting radio-frequency cavity cryomodule assemblies. This application requires cryogenic testing to demonstrate that this transition joint remains leak-tight when sealing superfluid helium. To simulate a titanium cavity vessel connection to a stainless steel service pipe, bimetallic transition joints were paired together to fabricate piping assemblies. These piping assemblies were then tested in superfluid helium conditions at Fermi National Accelerator Laboratory test facilities. The transition joint test program will be described. Fabrication experience and test results will be presented
Capacity Utilization Factor (CUF) of the 70kW on-grid solar station in the dry climate of Termez
The aim of the present study was to assess the installed capacity utilization factor and the suitability of a 70kW photovoltaic plant placed on the roof of a dormitory located at Termez city (Termez state university). We can report the energy to production directly through mobile devices. CUF is one of the quantities that shows the performance quality of each power generating station. The results of our research cover two months autumn and winter. Through this, the theoretically estimated minimum values of CUF on the least sunny days have also been proven in real values. It is estimated that the annual result of this value will be around 15%-20%. Because in the winter months, the value of individual CUF on open days increases by 20%. An estimated 15.68 mln kg of CO2 was avoided due to the generation of 22.4MWh of energy. This is a small improvement in the environment and energy sector
Age and gender aspects of the association of generalized obesity with development of fatal and nonfatal cardiovascular events (results of the prospective cohort study âInterepepidâ)
Background. Currently, obesity has become one of the most important medical and social problems in the world due to its high prevalence. Numerous literature data indicate that high BMI is associated with increased mortality from cardiovascular diseases.The aim: to study the relationship between overweight and generalized obesity with the development of fatal and non-fatal cardiovascular events among residents of the Chui region of the Kyrgyz Republic, taking into account gender and age.Material and methods. This study was carried out as part of the international crosssectional epidemiological study âInterepidâ. The total follow-up period was 7 years. Life status at the end of the follow-up period was monitored in 1096 respondents out of 1341 initial cohorts (response â 82.1 %). The endpoints were cases of fatal and non-fatal cardiovascular events. The frequency of events was assessed using methods of analysis of survival (Cox proportional hazard regression model, parametric survival models, survival by the Kaplan â Meier method).Results. A total of 181 cases of fatal and non-fatal cardiovascular events (16.44 %) were recorded during the follow-up. In persons with normal body weight, the incidence of cardiovascular complications was 10 %. In overweight individuals, the value of this indicator increased and reached 17.99 % (pË 0.001), and in individuals with obesity â 24.5 % (pË 0.0001). The increase in the frequency of events with the increase in body mass index did not depend on the gender of the respondents but was typical only for people under 60 years of age. For elderly patients, there was no relationship between BMI and the development of cardiovascular complications. In contrast, the relative risk had an insignificant tendency to decrease by 2.6 % for every 1 kg/m2 increase in body mass index (RR â 0.974; 95% CI: 0.924â1.025).Conclusion. The increase of body mass index above 25 kg/m2 is an independent risk factor for the development of fatal and non-fatal cardiovascular events in the analyzed cohort of the Chui region residents, regardless of gender, but only in persons under 60 years of age
Search for R-parity Violating Supersymmetry in Dimuon and Four-Jets Channel
We present results of a search for R-parity-violating decay of the neutralino
chi_1^0, taken to be the Lightest Supersymmetric Particle. It is assumed that
this decay proceeds through one of the lepton-number violating couplings
lambda-prime_2jk (j=1,2; k=1,2,3). This search is based on 77.5 pb-1 of data,
collected by the D0 experiment at the Fermilab Tevatron in ppbar collisions at
a center of mass energy of 1.8 TeV in 1992-1995.Comment: 10 pages, 3 figure
Direct Search for Charged Higgs Bosons in Decays of Top Quarks
We present a search for charged Higgs bosons in decays of pair-produced top
quarks in pbar p collisions at sqrt(s) = 1.8 TeV using 62.2 pb^-1 of data
recorded by the D0 detector at the Fermilab Tevatron collider. No evidence is
found for signal, and we exclude at 95% confidence most regions of the (M
higgs, tan beta) parameter space where the decay t->H b has a branching
fraction greater than 0.36 and B(H -> tau nu) is large.Comment: 11 pages, 4 figures, submitted to Phys. Rev. Let
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