52 research outputs found

    Cardiotoxic Effects of Yew Tree and Pink Periwinkle Alkaloids

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    Antitumour herbal medicines based on pink periwinkle and yew tree alkaloids are included in combination therapies for many types of cancer. The use of these classes of products may entail cardiotoxic effects leading to life-threatening conditions. The aim of the study was to analyse scientific literature on cardiotoxic effects of anticancer drugs based on yew tree alkaloids (taxanes) and pink periwinkle alkaloids (vinca alkaloids). The results of the analysis demonstrated that the main manifestations of taxane-induced cardiotoxicity were bradycardia, atrioventricular block, atrial and ventricular arrhythmias. Concomitant use of taxanes and anthracycline antibiotics exacerbated cardiotoxic effects of both drug classes. The use of vinca alkaloids was associated with haematological toxicity in the form of neutropenia, while cardiotoxic effect was rarely observed during monotherapy. Raising awareness among oncologists, cardiologists, and other specialists involved in the management of cancer patients about potential cardiac complications of antitumour therapy contributes to early detection of adverse reactions and allows for individual correction of treatment regimens, especially in patients with predisposition to cardiovascular disease

    Monopolar and dipolar relaxation in spin ice Ho2_2Ti2_2O7_7

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    When degenerate states are separated by large energy barriers, the approach to thermal equilibrium can be slow enough that physical properties are defined by the thermalization process rather than the equilibrium. The exploration of thermalization pushes experimental boundaries and provides refreshing insights into atomic scale correlations and processes that impact steady state dynamics and prospects for realizing solid state quantum entanglement. We present a comprehensive study of magnetic relaxation in Ho2_2Ti2_2O7_7 based on frequency-dependent susceptibility measurements and neutron diffraction studies of the real-time atomic-scale response to field quenches. Covering nearly ten decades in time scales, these experiments uncover two distinct relaxation processes that dominate in different temperature regimes. At low temperatures (0.6K<T<1K) magnetic relaxation is associated with monopole motion along the applied field direction through the spin-ice vacuum. The increase of the relaxation time upon cooling indicates reduced monopole conductivity driven by decreasing monopole concentration and mobility as in a semiconductor. At higher temperatures (1K<T<2K) magnetic relaxation is associated with the reorientation of monopolar bound states as the system approaches the single-spin tunneling regime. Spin fractionalization is thus directly exposed in the relaxation dynamics

    Can Galactic Observations Be Explained by a Relativistic Gravity Theory?

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    We consider the possibility of an alternative gravity theory explaining the dynamics of galactic systems without dark matter. From very general assumptions about the structure of a relativistic gravity theory we derive a general expression for the metric to order (v/c)2(v/c)^2. This allows us to compare the predictions of the theory with various experimental data: the Newtonian limit, light deflection and retardation, rotation of galaxies and gravitational lensing. Our general conclusion is that the possibility for any gravity theory to explain the behaviour of galaxies without dark matter is rather improbable.Comment: 12p, REVTeX 3.

    Electron transport in a quasi-one dimensional channel on suspended helium films

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    Quasi-one dimensional electron systems have been created using a suspended helium film on a structured substrate. The electron mobility along the channel is calculated by taking into account the essential scattering processes of electrons by helium atoms in the vapor phase, ripplons, and surface defects of the film substrate. It is shown that the last scattering mechanism may dominate the electron mobility in the low temperature limit changing drastically the temperature dependence of the mobility in comparison with that controlled by the electron-ripplon scattering.Comment: 4 pages, 1 figur

    A Low Complexity Scheme for Entanglement Distributor Buses

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    For technological purposes and theoretical curiosity, it is very interesting to have a building block that produces a considerable amount of entanglement between on-demand sites through a simple control of a few sites. Here, we consider permanently-coupled spin networks and study entanglement generation between qubit pairs to find low-complexity structures capable of generating considerable entanglement between various qubit pairs. We find that in axially symmetric networks the generated entanglement between some qubit pairs is rather larger than generic networks. We show that in uniformly-coupled spin rings each pair can be considerably entangled through controlling suitable vertices. To set the location of controlling-vertices, we observe that the symmetry has to be broken for a definite time. To achieve this, a magnetic flux can be applied to break symmetry via Aharonov-Bohm effect. Such a set up can serve as an efficient entanglement distributor bus in which each vertex-pair can be efficiently entangled through exciting only one fixed vertex and controlling the evolution time. The low-complexity of this scheme makes it attractive for use in nanoscale quantum information processors.Comment: 23 pages, 4 figures, Major revision, title changed, published versio

    Superconducting Nanocircuits for Topologically Protected Qubits

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    For successful realization of a quantum computer, its building blocks (qubits) should be simultaneously scalable and sufficiently protected from environmental noise. Recently, a novel approach to the protection of superconducting qubits has been proposed. The idea is to prevent errors at the "hardware" level, by building a fault-free (topologically protected) logical qubit from "faulty" physical qubits with properly engineered interactions between them. It has been predicted that the decoupling of a protected logical qubit from local noises would grow exponentially with the number of physical qubits. Here we report on the proof-of-concept experiments with a prototype device which consists of twelve physical qubits made of nanoscale Josephson junctions. We observed that due to properly tuned quantum fluctuations, this qubit is protected against magnetic flux variations well beyond linear order, in agreement with theoretical predictions. These results demonstrate the feasibility of topologically protected superconducting qubits.Comment: 25 pages, 5 figure

    Experimental research of nephroprotective activity benophylline in myoglobinurical acute kidney injury in rats

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    Matviychuk O. P., Matviychuk A. V., Gladchenko O. M., Taran A. V. Experimental research of nephroprotective activity benophylline in myoglobinurical acute kidney injury in rats. Journal of Education, Health and Sport. 2017;7(4):774-786. eISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.583153 http://ojs.ukw.edu.pl/index.php/johs/article/view/4477 The journal has had 7 points in Ministry of Science and Higher Education parametric evaluation. Part B item 1223 (26.01.2017). 1223 Journal of Education, Health and Sport eISSN 2391-8306 7 © The Author (s) 2017; This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. The authors declare that there is no conflict of interests regarding the publication of this paper. Received: 12.04.2017. Revised: 10.04.2017. Accepted: 25.04.2017. EXPERIMENTAL RESEARCH OF NEPHROPROTECTIVE ACTIVITY BENOPHYLLINE IN MYOGLOBINURICAL ACUTE KIDNEY INJURY IN RATS O. P. Matviychuk, A. V. Matviychuk, O. M. Gladchenko, A. V. Taran National University of Pharmacy, Kharkiv, Ukraine Аbstract The results in this article demonstrate of the dosage of the nephroprotective activity of the newly 7,8-substituted of theophylline are shown: 7-n-methylbenzyl-8-n-bromobenzylidenhydrazinotheophylline (code name benofillin). Nephroprotective activity was supplemented by of acute renal failure, which was called one-time intramuscularly introduced to the thigh 50% water solution of glycerol. Blowing a benofillin on the function of kidneys in rats were given to the minds of the water load. Evaluation of excretory function of kidneys held for the showers of diuresis, glomerular filtration rate, creatinine concentrations, relative reabsorption of water, excretion of potassium and calcium ions, protein content in the urine and it excretion, filtration charge and reabsorption of sodium ions. The result of the dosage was shown that when therapeutic and preventive application of benofillin the quantity of diuresis increased on 1/9 times in comparison with the pathologies. Under the action of benofillin a decrease in the level of urea in blood serum in 1/5 times. The level of creatinin in blood serum slightly increased (1.1 times compared with pathology). The level of contents of urea and creatinine in urine increased in 2.3 and 2.2 times respectively, excretion of these substances by the kidneys has grown 4.6 times that 5 times respectively, which indicates about improvement of the excretory function of the kidneys. The analysis of changes in biochemical indicators in blood and urine in rats demonstrate, hat in the treatment-and-prophylactic use of benofillin the basic parameters of the visible function of kidneys are normalized. On the background of the treatment-and-prophylactic use of benofillin glomerular filtration rate and tubular reabsorption were increased in 4.7 and 1.1 times respectively compared with pathology. The level of sodium in blood serum not changes respectively with control pathology and intact control. The level of sodium in urine decreased in 2.4 times compared with control pathology. Filtration charge and relative reabsorption increased in 7 times each of one decreased in control pathology, relative reabsorption increased in 1.2 times, sodium excretion was has not changed. When applying benofillin the level of protein in the urine was identical to the control. The conducted studies showed the presence of nephroprotektive activity in benofillin, what is expressed in decreasing of proteinuria, excretion of sodium in the urine and retention hyperaemia, increased glomerular filtration rate and diuresis, normalization of acid-forming function of the kidneys. Key words: acute renal failure, nephroprotective activity, diuresis, urea, creatinine, proteinuria, benofillin
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