707 research outputs found

    Superconducting single-mode contact as a microwave-activated quantum interferometer

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    The dynamics of a superconducting quantum point contact biased at subgap voltages is shown to be strongly affected by a microwave electromagnetic field. Interference among a sequence of temporally localized, microwave-induced Landau-Zener transitions between current carrying Andreev levels results in energy absorption and in an increase of the subgap current by several orders of magnitude. The contact is an interferometer in the sense that the current is an oscillatory function of the inverse bias voltage. Possible applications to Andreev-level spectroscopy and microwave detection are discussed

    Electromechanics of charge shuttling in dissipative nanostructures

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    We investigate the current-voltage (IV) characteristics of a model single-electron transistor where mechanical motion, subject to strong dissipation, of a small metallic grain is possible. The system is studied both by using Monte Carlo simulations and by using an analytical approach. We show that electromechanical coupling results in a highly nonlinear IV-curve. For voltages above the Coulomb blockade threshold, two distinct regimes of charge transfer occur: At low voltages the system behave as a static asymmetric double junction and tunneling is the dominating charge transfer mechanism. At higher voltages an abrupt transition to a new shuttle regime appears, where the grain performs an oscillatory motion back and forth between the leads. In this regime the current is mainly mediated by charges that are carried on the grain as it moves from one lead to the other.Comment: 8 pages, 10 figures, final version to be published in PR

    The Effect of a Frailty Management Program on the Rehabilitation of Elderly Patients after Surgical Treatment

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    The article performs the results of rehabilitation programs realized among senile patients after videolaparoscopic cholecystectomy, based on specific for geriatrics senile patients’ status assessment methods with determination of frailty and geriatric syndromes exten

    The development of Russian health-care system: problems and prospects

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    Thus, the implementation of the above mentioned points will assist the efficiency of a modem health-care system in general. It also helps to provide affordable and quality medical service on the basis of common requirements and approaches according to the latest achieve ments of scientific and technical progress, which will be guarantee of sustainable socio­ economic development of Russia in the long ter

    Age peculiarities of the pro-inflammatory component of cytokine profile in chronic odontogenic infection affected by polymorbid pathology

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    This study aimed to study the features of pro-inflammatory component of the cytokine profile in chronic odontogenic infection affected by polymorbid patholog

    Influence mechanisms of mineralocorticoid receptor antagonist (spironolactone) among elderly patients with chronic heartfailure against ischemic disease

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    It was determined that a significant positive dynamics of TNF-synthesis suppression by 67.0% (p 0.0001) was established in the 4th group of patients taking combined therapy with the blocker of mineralocorticoid receptors with spironolacton

    A nanomechanical resonator shuttling single electrons at radio frequencies

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    We observe transport of electrons through a metallic island on the tip of a nanomechanical pendulum. The resulting tunneling current shows distinct features corresponding to the discrete mechanical eigenfrequencies of the pendulum. We report on measurements covering the temperature range from 300 K down to 4.2 K. We explain the I-V curve, which differs from previous theoretical predictions, with model calculations based on a Master equation approach.Comment: 5 pages, 4 jpeg-figure

    Course of acute coronary syndrome in patients with fraillty

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    The goal of this study was to study the course and outcome of acute coronary syndrome with ST-segment elevation and without ST-segment elevation in patients of older age groups with frailt

    Phase Dependent Thermopower in Andreev Interferometers

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    We report measurements of the thermopower S of mesoscopic Andreev interferometers, which are hybrid loops with one arm fabricated from a superconductor (Al), and one arm from a normal metal (Au). S depends on the phase of electrons in the interferometer, oscillating as a function of magnetic flux with a period of one flux quantum (= h/2e). The magnitude of S increases as the temperature T is lowered, reaching a maximum around T = 0.14 K, and decreases at lower temperatures. The symmetry of S oscillations with respect to magnetic flux depends on the topology of the sample.Comment: 4 pages, 4 figure
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