106 research outputs found

    PECULIARITIES OF HIP JOINT PROSTHESIS IN PATIENTS WITH RHEUMATOID ARTHRITIS

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    The aim. To improve the results of treatment of patients with rheumatic lesions of the hip joint by choosing the best options for endoprosthetics and postoperative rehabilitation of pa-tients. Materials and research methods. The object of the study was 125 patients with RA with TBS lesion, who underwent TB TBS in the Department of Adult Orthopedics of the UzNII of Traumatology and Orthopedics and the Department of Traumatology of the Clinical Hospital No. 1 for the period 2011 to 2017. In the foreground of preoperative planning, patients received conservative treatment on an outpatient basis for 2 weeks from a rheumatologist. After normali-zation of the rheumatic test indices, the patients came to us for surgical treatment. All patients were divided into 2 groups - the main and control. The main group consisted of 75 patients; in addition to the traditional method of surgical treatment, they used a device developed by us to determine the depth of the acetabulum during surgery, which made it possible to atraumatically, accurately and quickly determine the landing depth of the acetabular component of the endoprosthesis. Also, after surgery, the developed splint was used to develop the TB joint. The control group included 50 patients who underwent traditional methods of surgical treatment and after surgery without using a tire to rehabilitate patients. The age of patients ranged from 18 to 75 years, on average - 38 years. Of the total number of 125 sick men, there were 50 (40%), women 75 (60%). Results. Evaluation of long-term treatment results showed that good results in the main group (81.5%) were significantly greater than the control group (75%). Unsatisfactory results were obtained in patients of the main (1.5%) and control groups (5%). Conclusion. In the treatment of patients with RA, the use of cementless endoprostheses provides the possibility of widespread introduction of TBS endoprosthetics. In patients with RA with severe osteoporosis, protrusive coxitis and defects in the walls of the acetabulum, the justi-fied method is TE TBS using bone cement

    Superconductive proximity effect in interacting disordered conductors

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    We present a general theory of the superconductive proximity effect in disordered normal--superconducting (N-S) structures, based on the recently developed Keldysh action approach. In the case of the absence of interaction in the normal conductor we reproduce known results for the Andreev conductance G_A at arbitrary relation between the interface resistance R_T and the diffusive resistance R_D. In two-dimensional N-S systems, electron-electron interaction in the Cooper channel of normal conductor is shown to strongly affect the value of G_A as well as its dependence on temperature, voltage and magnetic field. In particular, an unusual maximum of G_A as a function of temperature and/or magnetic field is predicted for some range of parameters R_D and R_T. The Keldysh action approach makes it possible to calculate the full statistics of charge transfer in such structures. As an application of this method, we calculate the noise power of an N-S contact as a function of voltage, temperature, magnetic field and frequency for arbitrary Cooper repulsion in the normal metal and arbitrary values of the ratio R_D/R_T.Comment: RevTeX, 28 pages, 18 PostScript figures; added and updated reference

    Theory of Interaction Effects in N-S Junctions out of Equilibrium

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    We consider a normal metal - superconductor (N-S) junction in the regime, when electrons in the normal metal are driven out of equilibrium. We show that the non-equilibrium fluctuations of the electron density in the N-layer cause the fluctuations of the phase of the order parameter in the S-layer. As a result, the density of states in the superconductor deviates from the BCS form, most notably the density of states in the gap becomes finite. This effect can be viewed as a result of the time reversal symmetry breaking due to the non-equilibrium, and can be described in terms of a low energy collective mode of the junction, which couples normal currents in N-layer and supercurrents. This mode is analogous to the Schmid-Sch\"{o}n mode. To interpret their measurements of the tunneling current, Pothier {\em et. al} [Phys. Rev. Lett. {\bf 79}, 3490 (1997)] had to assume that the energy relaxation rate in the normal metal is surprisingly high. The broadening of the BCS singularity of the density of states in the S-layer manifest itself similarly to the broadening of the distribution function. Mechanism suggested here can be a possible explanation of this experimental puzzle. We also propose an independent experiment to test our explanation.Comment: 16 pages, 2 .eps figure

    Fractional plateaus in the Coulomb blockade of coupled quantum dots

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    Ground-state properties of a double-large-dot sample connected to a reservoir via a single-mode point contact are investigated. When the interdot transmission is perfect and the dots controlled by the same dimensionless gate voltage, we find that for any finite backscattering from the barrier between the lead and the left dot, the average dot charge exhibits a Coulomb-staircase behavior with steps of size e/2 and the capacitance peak period is halved. The interdot electrostatic coupling here is weak. For strong tunneling between the left dot and the lead, we report a conspicuous intermediate phase in which the fractional plateaus get substantially altered by an increasing slope.Comment: 6 pages, 4 figures, final versio

    Direct synthesized graphene-like film on SiO₂: Mechanical and optical properties

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    Exploiting CVD technique for carbon deposition from C₂H₂+H₂+N₂ mixture, a graphene-like film synthesized directly on SiO₂ surface of SiO₂-Si structure was obtained. The graphene-like film was grown under thin Ni layer that is easy exfoliated from graphene-SiO₂-Si structure. Surface of the film was sufficiently smooth and reveals no winkles and holes; it has a good homogeneity and perfect adhesion to SiO₂ layer. Studying the micro-Raman spectra showed a graphene-like structure of the film; using atomic force microscopic technique, the thickness of film was determined (0.6 nm). Using spectroscopic ellipsometry and simple Cauchy model enabled us to estimate optical parameters of this graphene-like film

    Shot Noise at High Temperatures

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    We consider the possibility of measuring non-equilibrium properties of the current correlation functions at high temperatures (and small bias). Through the example of the third cumulant of the current (S3{\cal{S}}_3) we demonstrate that odd order correlation functions represent non-equilibrium physics even at small external bias and high temperatures. We calculate S3=y(eV/T)e2I{\cal{S}}_3=y(eV/T) e^2 I for a quasi-one-dimensional diffusive constriction. We calculate the scaling function yy in two regimes: when the scattering processes are purely elastic and when the inelastic electron-electron scattering is strong. In both cases we find that yy interpolates between two constants. In the low (high) temperature limit yy is strongly (weakly) enhanced (suppressed) by the electron-electron scattering.Comment: 11 pages 4 fig. submitted to Phys. Rev.

    Coulomb effects in granular materials at not very low temperatures

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    We consider effects of Coulomb interaction in a granular normal metal at not very low temperatures suppressing weak localization effects. In this limit calculations with the initial electron Hamiltonian are reduced to integrations over a phase variable with an effective action, which can be considered as a bosonization for the granular metal. Conditions of the applicability of the effective action are considered in detail and importance of winding numbers for the phase variables is emphasized. Explicit calculations are carried out for the conductivity and the tunneling density of states in the limits of large g1g\gg 1 and small g1g\ll 1 tunnelling conductances. It is demonstrated for any dimension of the array of the grains that at small gg the conductivity and the tunnelling density of states decay with temperature exponentially. At large gg the conductivity also decays with decreasing the temparature and its temperature dependence is logarithmic independent of dimensionality and presence of a magnetic field. The tunnelling density of states for g1g\gg 1 is anomalous in any dimension but the anomaly is stronger than logarithmic in low dimensions and is similar to that for disordered systems. The formulae derived are compared with existing experiments. The logarithmic behavior of the conductivity at large gg obtained in our model can explain numerous experiments on systems with a granular structure including some high TcT_{c} materials.Comment: 30 page

    Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV

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    The elliptic, v2v_2, triangular, v3v_3, and quadrangular, v4v_4, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions and (anti-)protons in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV with the ALICE detector at the Large Hadron Collider. Results obtained with the event plane and four-particle cumulant methods are reported for the pseudo-rapidity range η<0.8|\eta|<0.8 at different collision centralities and as a function of transverse momentum, pTp_{\rm T}, out to pT=20p_{\rm T}=20 GeV/cc. The observed non-zero elliptic and triangular flow depends only weakly on transverse momentum for pT>8p_{\rm T}>8 GeV/cc. The small pTp_{\rm T} dependence of the difference between elliptic flow results obtained from the event plane and four-particle cumulant methods suggests a common origin of flow fluctuations up to pT=8p_{\rm T}=8 GeV/cc. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least pT=8p_{\rm T}=8 GeV/cc indicating that the particle type dependence persists out to high pTp_{\rm T}.Comment: 16 pages, 5 captioned figures, authors from page 11, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186

    Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}} = 2.76 TeV

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    The inclusive transverse momentum (pTp_{\rm T}) distributions of primary charged particles are measured in the pseudo-rapidity range η<0.8|\eta|<0.8 as a function of event centrality in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}}=2.76 TeV with ALICE at the LHC. The data are presented in the pTp_{\rm T} range 0.15<pT<500.15<p_{\rm T}<50 GeV/cc for nine centrality intervals from 70-80% to 0-5%. The Pb-Pb spectra are presented in terms of the nuclear modification factor RAAR_{\rm{AA}} using a pp reference spectrum measured at the same collision energy. We observe that the suppression of high-pTp_{\rm T} particles strongly depends on event centrality. In central collisions (0-5%) the yield is most suppressed with RAA0.13R_{\rm{AA}}\approx0.13 at pT=6p_{\rm T}=6-7 GeV/cc. Above pT=7p_{\rm T}=7 GeV/cc, there is a significant rise in the nuclear modification factor, which reaches RAA0.4R_{\rm{AA}} \approx0.4 for pT>30p_{\rm T}>30 GeV/cc. In peripheral collisions (70-80%), the suppression is weaker with RAA0.7R_{\rm{AA}} \approx 0.7 almost independently of pTp_{\rm T}. The measured nuclear modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/284

    Two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

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    The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/388
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