2,662 research outputs found

    Book Review: Russia Abroad: An Anthology of Modern Philosophical Thought

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    “In September and November 1922, two ‘philosophical steamboats-‘ – the “Oberburgomaster Haken” and the “Prussia”- transported about 160 people from the Soviet city of Petrograd to the German city of Stettin. ‘Outstanding figures of Russian philosophy, culture and science’ were forced to emigrate including Nikolai Berdyaev, Semyon Frank, Ivan Ilyin, Lev Karsavin, Nikolai Lossky and many others. ” This is how Mikhail Sergeev, Doctor of Philosophy of the University of the Arts (Philadelphia, USA), and the initiator and compiler of Russia Abroad: An Anthology of Modern Philosophical Thought begins his preface

    Religion and Globalization: Crossroads and Opportunities

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    A conversation between the First Vice-President of the Russian Philosophical Society, Doctor of Philosophy, Professor of Moscow State University, Alexander Chumakov and the editor of the special series Contemporary Russian Philosophy at Brill, the Nertherlands, Doctor of Philosophy, Professor Mikhail Sergeev

    On the spectrum of a Hamiltonian defined on su_q(2) and quantum optical models

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    Analytical expressions are given for the eigenvalues and eigenvectors of a Hamiltonian with su_q(2) dynamical symmetry. The relevance of such an operator in Quantum Optics is discussed. As an application, the ground state energy in the Dicke model is studied through su_q(2) perturbation theory.Comment: 11 pages, LaTeX, content change

    The giant effect of magnetic ordering on a sound velocity in a sigma-Fe55Cr45 alloy

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    We studied atomic dynamics of sigma-Fe(100-x)Cr(x) (x=45 and 49.5) alloys using nuclear inelastic scattering of synchrotron radiation. For the sigma-Fe55Cr45 alloy, the derived reduced iron-partial density of phonon states reveal a huge difference in the low-energy region between magnetic and paramagnetic states. The latter implies a ca.36% increase of the sound velocity in the magnetic phase, which testifies to a magnetically-induced hardening of the lattice.Comment: 8 pages, 3 figures, 17 reference

    The trace element blood composition variation of acute interstitial pancreatitis

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    Acute interstitial pancreatitis (AIP) is an acute inflammatory disease of the pancreatic gland with autodigestion of pancreatic tissue often incurring variable damage to adjacent organs. Objective: To improve the diagnostic results of acute pancreatitis which are based on the level of trace elements in blood plasma. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3359

    Role of QCD compositeness in the production of scalar and tensor mesons through single-photon annihilation e+eγγS(T)e^+ e^- \to \gamma^* \to \gamma S(T)

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    We study the exclusive production of scalar S=0++S = 0^{++} and tensor T=2++T = 2^{++} mesons through single-photon annihilation e+eγγS(T)e^+ e^- \to \gamma^* \to \gamma S(T). Using QCD compositeness of the involved hadrons considered as quark-antiquark systems, the prediction for the scaling of the differential cross sections of these processes is dσ/dt1/s3d\sigma/dt \sim 1/s^3 at large ss. We further derive the scaling of the γγS\gamma^\ast \to \gamma S and γγT\gamma^\ast \to \gamma T transition form factors: FγγS(s)1/sF_{\gamma^\ast\gamma S}(s) \sim 1/s and FγγT(s)1/s2F_{\gamma^\ast\gamma T}(s) \sim 1/s^2. Results for the respective cross sections of the scalar and tensor meson production are presented. Note, when scalar and tensor mesons are considered as tetraquark systems of two tightly bound color diquarks, corresponding to them transition form factors and differential cross sections have the same falloffs as in case of quark-antiquark picture. For other tetraquark or two-hadron molecules configurations the transition form factors FγγS(T)(s)F_{\gamma^\ast\gamma S(T)}(s) and the differential cross section dσ/dtd\sigma/dt have additional 1/s1/s and 1/s21/s^2 falloffs, respectively.Comment: 7 page

    The Novel Use of Nitroxide Antioxidants as Free Radical Scavengers in Ultra-High Molecular Weight Polyethylene (UHMWPE) for Total Joint Replacements

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    Ultra-high molecular weight polyethylene (UHMWPE) has been the standard load-bearing material used in total joint replacements since the 1960s. However, oxidative degradation can lead to premature aging and wear of UHMWPE, requiring implant revision. The novel use of nitroxide antioxidants to prevent oxidation in UHMWPE was proposed and the resulting structure and property changes were evaluated in this work. Standard sterilization and crosslinking methods of Co-60 gamma or high energy electron beam radiation produce alkyl free radicals on the polymer chain. Alkyl radicals react to form bimolecular crosslinks and long-lived allyl radicals at high dose rates; at low dose rates they tend to react with oxygen to form peroxyl radicals. The peroxyl radicals further interact with the polymer chain producing hydroperoxides and more free radicals, leading to oxidative degradation. As an alternative to post-irradiation remelting, which allows radical recombination but reduces fatigue strength, antioxidants can be introduced into UHMWPE to scavenge residual radicals. Nitroxides are stable organic compounds that have a strong paramagnetic signal and are very efficient in preventing lipid peroxidation and in providing radioprotection in biological tissues. The nitroxides used are 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and 4-hydroxy-TEMPO (Tempol). Through radical-radical interactions, radiolytically-produced alkyl radicals in UHMWPE are scavenged by the nitroxide radical. This is demonstrated through Electron Paramagnetic Resonance (EPR) spectroscopy where the paramagnetic nitroxide signal decays as it interacts with carbon-centered radicals in UHMWPE. Pulse radiolysis kinetics studies also show that alkyl radicals in UHMWPE preferentially react with nitroxides in the absence of oxygen. Controlled infiltration of UHMWPE with nitroxides is also observed using EPR. The resulting crosslink densities were investigated using Thermomechanical Analysis. It was observed that the addition of nitroxides after irradiation does not alter the crosslink density. Tensile testing of crosslinked and nitroxide-doped UHMWPE demonstrates increased ultimate tensile strength and toughness and the material exhibits an increase in crystallinity. Additionally, accelerated aging of specimens containing trace levels of nitroxide show very low oxidation levels when placed in an aggressive oxygen environment. Consequently, low concentrations of nitroxides diffused into UHMWPE after crosslinking produce an oxidation-resistant and highly crosslinked material for improved implant performance
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