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Search Results: 1 - 10 of 154051 matches for " B.Ya. Bart "
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Clinical significance of anemic syndrome in patients with chronic heart failure
V.N. Larina,B.Ya. Bart,V.G. Larin
Rational Pharmacotherapy in Cardiology , 2010,
Abstract: Aim. To evaluate the anemia prevalence and its impact on chronic heart failure (CHF) course.Methods. A total of 228 outpatients (86 women and 196 men, aged 39-85 y.o.) with clinically stable CHF (II-IV functional class according to NYHA) were studied. Anemia was defined by the WHO criteria (hemoglobin levels <13 g/dl in men and <12 g/dl in women).Results. Anemia was found in 18,8% of CHF patients. In all the cases anemia was mild (hemoglobin levels >9 g/dl). Anemia rate did not differ significantly in patients with reduced (18,5%) and preserve (19,1%) or left ventricle ejection fraction (LV EF) (р=0,743). Anemic and non anemic patients were similar in terms of gender, NYHA functional class, heart rate and LV EF. The rate of anemic patients increased significantly up to 35,8% in creatinine clearance <60ml/min. Anemic patients were older (p<0,001), had longer CHF duration (p=0,014), lower body mass index (p=0,041), had diabetes more often (p=0,004, χ2=8,01) in comparison with non anemic patients. Deficiency of iron, vitamin B12 or folic acid was a reason of anemia in 35,8%, 9,4% and 15,1% of patients, respectively. Anemia reason was not detected in 39,7% of patients.Conclusion. Anemia in patients with CHF is associated with age, impaired renal function, diabetes and high hospitalization rate because of CHF deterioration.
Factors effecting the decompensation of chronic heart failure in the elderly
V.N. Larina,B.Ya. Bart,E.A. Vartanyan
Rational Pharmacotherapy in Cardiology , 2013,
Abstract: Aim. To identify risk factors of decompensation of chronic heart failure (CHF) and related hospitalization in elderly outpatients.Material and methods. The total of 248 patients aged 60–85 years with CHF NYHA class II-IV were enrolled into the study. The first group consisted of 87 (35.1%) patients who required hospitalization due to CHF decompensation during the follow-up, the second group - of 161 patients without need for hospital admission. All the patients had undergone clinical and laboratory examination, estimation of CHF severity by the Scale of clinical state, assessment of quality of life and 6-minute walk test (6MWT), echocardiography.Results. Patients were matched for age, gender, disability occurrence, education level, body mass index, quality of life, hemodynamic parameters, incidence rates of anemia, diabetes mellitus and atrial fibrillation. CHF was more severe in patients who had required hospitalization (p<0.001), they were more often diagnosed with left ventricular aneurysm (p=0.001), chronic kidney disease (p=0.001), left ventricular ejection fraction (LVEF)<35% (p<0.001), history of stroke (p<0.001), III-IV degree mitral regurgitation (p=0.007), hyperuricemia (p<0.001), lower exercise tolerance (p=0.007) compared with patients without hospitalization. Higher functional class of CHF (OR=0.29; 95% CI 0.13–0.69; p=0.003), LVEF<35% (OR 0.37; 95% CI 0.18–0.76; p=0.007), chronic kidney disease (OR=0.29; 95% CI 0.13–0.68; p=0.004) and hyperuricemia (OR=0.23; 95%CI 0.10–0.50; p<0.001) were shown to be independent risk factors of CHF decompensation that required hospital admission in elderly patients.Conclusuion. High FC of CHF, low LVEF, hyperuricemia and renal dysfunction play a key role in CHF decompensation and related hospitalization in elderly patients.
New trends in nanoscale compounds for energy storage
Z.A. Stotsko,B.Ya. Venhryn
Journal of Achievements in Materials and Manufacturing Engineering , 2012,
Abstract: Purpose: Mechanism of supramolecular complexes C formation and investigation of theirelectrochemical characteristics were the aim of this paper. Supramolecular complexes were created by insertingan organic receptor into nano/mesopores of activated carbon.Design/methodology/approach: Electrochemical studies of supramolecular complexes C werecarried out by means of impedance spectroscopy, cyclic voltammetry and galvanostatic cycling.Findings: The possibility to combine the capacitive storage with faradaic energy generation in one unit isproved. It can be reached by means of active electrode formation as a supramolecular complex C.It is shown that faradaic generation of energy occurs at low positive potentials, whereas the capacitive one athigher potentials. Method of synthesis of blue graphite is developed.Research limitations/implications: This research is a complete and accomplished work.Practical implications: Supramolecular complexes, obtained in this work, could be regarded as promisingelectrode materials in devices of energy generation, storage and transformation.Originality/value: This work is of urgent importance for physics and chemistry of energy generation, storageand transformation, because it opens new possibilities to new highly effective electrode materials search andenables to reach a high values of functional characteristics.
Porous structure of carbon-based materials studied by means of X-ray small angle scattering method
B.Ya. Venhryn,I.I. Grygorchak,Yu.O. Kulyk,S.I. Mudry
Optica Applicata , 2008,
Abstract: The porous structure of carbon-graphite materials: styrene-divinylbenzene copolymer (SBC) and fruit stones (FS) has been studied by means of X-ray small angle scattering method. The angular dependences of scattered intensities have been obtained and analyzed by means of the Guinier method. The main parameters of porous structure have been determined (inertia radius, pore size distribution functions, specific surface areas).
Supramolecular complexes C<18-crown- ether-6> and their application in devices for energy generation, storage and transformation
B.Ya. Venhryn,Z.A. Stotsko,I.I. Grygorchak,S.I. Mudry
Archives of Materials Science and Engineering , 2011,
Abstract: Purpose: Formation of supramolecular complexes C<18-crown-ether-6> and investigation of their electrochemical characteristics was the aim of this paper. An organic receptor is inserted in nano/mesopores of activated carbon of these supramolecular complexes.Design/methodology/approach: Electrochemical studies of supramolecular complexes C<18-crown-ether-6> were carried out by means of impedance spectroscopy, cyclic voltammetry and galvanostatic cycling.Findings: It is shown that Faraday generation of energy occurs at low positive potentials whereas the capacitive storage – at higher potentials. As result the value of specific capacitance for AC of faradaic process 10000 F/g was reached as well as 154 F/g of non-faradaic process, whereas the same parameters for BAC equal 13350 F/g and 80 F/g, respectively.Research limitations/implications: This research is a complete and accomplished work.Practical implications: Supramolecular complexes, obtained in this work, could be regarded as promising electrode materials in devices of energy generation, storage and transformation.Originality/value: This work is of urgent importance for physics and chemistry of energy generation, storage and transformation, because it opens new possibilities to new highly effective electrode materials search and enables to reach a high values of functional characteristics.
Changes in the fractal and electronic structures of activated carbons produced by ultrasonic radiation and the effect on their performance in supercapacitors
B.Ya. Venhryn,I.I. Grygorchak,Z.A. Stotsko,Yu.O. Kulyk
Archives of Materials Science and Engineering , 2012,
Abstract: Purpose: Effect of ultrasonic irradiation on change of electron structure as well as fractal one of activated carbons and motivation that these changes are most responsible for the improvement of functional parameters in supercapacitors, were the aim of this paper.Design/methodology/approach: Experimental studies were carried out by means of impedance spectroscopy, cyclic voltammetry, X-Ray diffraction, small angle X-Ray diffraction, X-Ray photoelectron spectroscopy, IR-spectroscopy, Micro-Raman spectroscopy and galvanostatic cycling methods.Findings: Ultrasonic modification of carbon is effective method to increase the specific capacitance as well as power of carbon-based supercapacitors. Changes of parameters of double electric layer are tightly related with change of fractal dimension and allow increasing the percolate mobility of charge carries.Research limitations/implications: This research is a complete and accomplished work.Practical implications: Carbon materials, modified by ultrasonic irradiation, can be used as promising electrode materials in energy storage devices of new generation.Originality/value: This work is of urgent importance for studying of physical and chemical processes in energy storage systems. It is shown that method of ultrasonic irradiation is highly effective for modification of carbon-based materials as electrodes in supercapacitors.
Calibration and Validation of Strategic Freight Transportation Planning Models with Limited Information  [PDF]
Bart Jourquin
Journal of Transportation Technologies (JTTs) , 2016, DOI: 10.4236/jtts.2016.65023
Abstract: Strategic transportation network models are often used as support tools in the framework of decisions to be taken at the policy level, such as the Trans-European Network projects. These models are mostly setup using aggregated or limited data. If their calibration is regularly mentioned in the literature, their validation is barely discussed. In this paper, several modal choice model specifications that make only use of explanatory variables available at the network level are described and applied to a large scale case. A validation exercise is performed at three levels of aggregation. The paper is designed from a strategic transport planning perspective, and does not present new modal choice formulations or assignment procedures. Its main added value is the focus on calibration and validation considerations. Despite the limited explanatory information used, the global performance of the best models can be considered as satisfactory. However, the quality of the models varies from mode to mode, the use of railway transport being the most difficult to predict without more specific input.
Estimating Elasticities for Freight Transport Using a Network Model: An Applied Methodological Framework  [PDF]
Bart Jourquin
Journal of Transportation Technologies (JTTs) , 2019, DOI: 10.4236/jtts.2019.91001
Abstract: This paper presents a general framework that can be used to estimate direct and cross elasticities for freight transport using a network model. This methodology combines operational research (network assignments in a geographical information system) with more classical econometrics (multinomial logit choice models). The application of the method to a real-world case is illustrated by a simple model that relies on the generalized cost of transport as the only explanatory variable in the utility function. The methodological framework allows, however, for the implementation of more complex functions. Beside the generalized cost functions for road, rail and inland waterways transport, the network model needs origin-destination matrixes and digitized networks. They are imported from ETIS Plus, a European transport policy information system. A set of direct and cross elasticities is presented. The estimated values are obtained using two methods: the first computes standard elasticities, while the second estimates arc elasticities. Figures are presented for Europe and for a large region around the Benelux countries, where more competition exists between the three modes of interest.
Clustering comparison of point processes with applications to random geometric models
Bart?omiej B?aszczyszyn,D. Yogeshwaran
Mathematics , 2012,
Abstract: In this chapter we review some examples, methods, and recent results involving comparison of clustering properties of point processes. Our approach is founded on some basic observations allowing us to consider void probabilities and moment measures as two complementary tools for capturing clustering phenomena in point processes. As might be expected, smaller values of these characteristics indicate less clustering. Also, various global and local functionals of random geometric models driven by point processes admit more or less explicit bounds involving void probabilities and moment measures, thus aiding the study of impact of clustering of the underlying point process. When stronger tools are needed, directional convex ordering of point processes happens to be an appropriate choice, as well as the notion of (positive or negative) association, when comparison to the Poisson point process is considered. We explain the relations between these tools and provide examples of point processes admitting them. Furthermore, we sketch some recent results obtained using the aforementioned comparison tools, regarding percolation and coverage properties of the Boolean model, the SINR model, subgraph counts in random geometric graphs, and more generally, U-statistics of point processes. We also mention some results on Betti numbers for \v{C}ech and Vietoris-Rips random complexes generated by stationary point processes. A general observation is that many of the results derived previously for the Poisson point process generalise to some "sub-Poisson" processes, defined as those clustering less than the Poisson process in the sense of void probabilities and moment measures, negative association or dcx-ordering.
Effective attraction induced by repulsive interaction in a spin-transfer system
Ya. B. Bazaliy
Physics , 2007, DOI: 10.1063/1.2822407
Abstract: In magnetic systems with dominating easy-plane anisotropy the magnetization can be described by an effective one dimensional equation for the in-plane angle. Re-deriving this equation in the presence of spin-transfer torques, we obtain a description that allows for a more intuitive understanding of spintronic devices' operation and can serve as a tool for finding new dynamic regimes. A surprising prediction is obtained for a planar ``spin-flip transistor'': an unstable equilibrium point can be stabilized by a current induced torque that further repels the system from that point. Stabilization by repulsion happens due to the presence of dissipative environment and requires a Gilbert damping constant that is large enough to ensure overdamped dynamics at zero current.
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