393 research outputs found

    Case Report: Penile Fracture from Entrapment of an Erect Penis in the African Bamboo Bed: A Case Report

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    Penile fracture is an uncommon urological emergency where the tunica albuginea ruptures as a result of blunt trauma to the erect penis. An 18 year old rural patient presented with penile fracture, presumably from entrapment of his penis in the African bamboo bed during nocturnal penile tumescence. He was managed surgically and retained normal erections on follow-up. Usingthe African bamboo bed without a mattress may lead to penile entrapment and fracture.Key Words: Penis, fracture, African, bamboo, be

    Dynamical generation of the constituent mass in expanding plasma

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    We investigate dynamics of the chiral transition in expanding quark-antiquark plasma produced in an ultra-relativistic heavy ion collision. The chiral symmetry break-down and dynamical generation of the constituent quark mass are studied within the linear sigma model and Nambu-Jona-Lasinio model. Time dependence of the quark and antiquark densities is obtained from the scaling solution of the relativistic Vlasov equation. Fast initial growth and strong oscillations of the constituent quark mass are found in the linear sigma model as well as in the NJL model, when derivative terms are taken into account.Comment: 7 pages, Latex. To appear in Physics Letters

    Dispersive approach to the axial anomaly and nonrenormalization theorem

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    Anomalous triangle graphs for the divergence of the axial-vector current are studied using the dispersive approach generalized for the case of higher orders of perturbation theory. The validity of this procedure is proved up to two-loop level. By direct calculation in the framework of dispersive approach we have obtained that the two-loop AVV amplitude is equal to zero. According to the Vainshtein's theorem the transversal part of the anomalous triangle is not renormalized in the chiral limit. We generalize this theorem for tha case of finite fermion mass in the triangle loop.Comment: 12 pages, version to appear in Physical Review

    The Nature of Thermopower in Bipolar Semiconductors

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    The thermoemf in bipolar semiconductors is calculated. It is shown that it is necessary to take into account the nonequilibrium distribution of electron and hole concentrations (Fermi quasilevels of the electrons and holes). We find that electron and hole electric conductivities of contacts of semiconductor samples with connecting wires make a substantial contribution to thermoemf.Comment: 17 pages, RevTeX 3.0 macro packag

    Nonlinear evolution of the momentum dependent condensates in strong interaction: the ``pseudoscalar laser''

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    We discuss the relaxation of the scalar and pseudoscalar condensates after a rapid quench from an initial state with fluctuations. If we include not only the zero-mode but also higher modes of the condensates in the classical evolution, we observe parametric amplification of those ``hard'' modes. Thus, they couple nonlinearly to the ``soft'' modes. As a consequence, domains of coherent pi-field emerge long after the initial spinodal decomposition. The momentum-space distribution of pions emerging from the decay of that momentum-dependent condensate is discussed.Comment: 6 Pages, REVTEX, 8 Figures; one reference and one figure adde

    Bioassay-guided optimization of lipid-based erythromycin microparticles

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    Purpose: To optimize erythromycin microparticles by in vitro bioassay methods based on its antibacterial activity. Methods: The microparticles were produced by high shear homogenization. The effects of different lipid-to-surfactant ratios were studied. The hydrodynamic size of the different batches was evaluated using dynamic light scattering while bioactive drug load per batch was assessed in agar using bioassay methods. The antimicrobial activities of selected batches were tested ex vivo by determination of reduction in bacteraemia following administration of the microparticles to infected animals. Results: All batches had particles with hydrodynamic sizes < 8.5 microns. Batch 7 with a 2: 5: 2.5 (drug: surfactant: stearic acid) ratio, represents the optimized batch with a hydrodynamic size of 2281 nm, a bioactive drug loading capacity (BLC) of 4.67 ± 0.70 % and bioactive drug entrapment  efficiency (BEE) of 10.51 %. The “microparticle MIC” against Staphylococcus aureus was 1.74 x 10-3 μg/ml. Despite containing lower amounts of erythromycin than the pure sample, the microparticles achieved comparable reduction in bacteraemia, with the optimized batch exhibiting lower variation in bacteraemia than the pure drug. Conclusion: Erythromycin microparticles have been successfully optimized with the aid of bioassay methods which has the advantage that only the bioactive drug concentration is factored in. This method eliminates problems posed by inadequate or non-discriminating chemical assay methods. Keywords: Microparticles, Erythromycin, Gastrointestinal, Bioavailability Antimicrobial, Bioactivity, Encapsulatio

    Axial anomaly: the modern status

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    The modern status of the problem of axial anomaly in QED and QCD is reviewed. Two methods of the derivation of the axial anomaly are presented: 1) by splitting of coordinates in the expression for the axial current and 2) by calculation of triangle diagrams, where the anomaly arises from the surface terms in momentum space. It is demonstrated, that the equivalent formulation of the anomaly can be given, as a sum rule for the structure function in dispersion representation of three point function of AVV interaction. It is argued, that such integral representation of the anomaly has some advantages in the case of description of the anomaly by contribution of hadronic states in QCD. The validity of the t'Hooft consistency condition is discussed. Few examples of the physical application of the axial anomaly are given.Comment: 17 pages, 3 figures, to be published in International Journal of Modern Physics A, few minor correction were done, two references were adde

    Chiral Fluid Dynamics and Collapse of Vacuum Bubbles

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    We study the expansion dynamics of a quark-antiquark plasma droplet from an initial state with restored chiral symmetry. The calculations are made within the linear σ\sigma model scaled with an additional scalar field representing the gluon condensate. We solve numerically the classical equations of motion for the meson fields coupled to the fluid-dynamical equations for the plasma. Strong space-time oscillations of the meson fields are observed in the course of the chiral transition. A new phenomenon, the formation and collapse of vacuum bubbles, is also predicted. The particle production due to the bremsstrahlung of the meson fields is estimated.Comment: 12 pages Revtex,5 figures, Figures modified, minor changes in text. To be published in Phys. Rev. Let

    Hall helps Ohm: some corrections to negative-U centers approach to transport properties of YBa2_2Cu3_3Ox_x and La2x_{2-x}Srx_xCuO4_4

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    For broad oxygen and strontium doping ranges, temperature dependences (T-dependences) of the normal state resistivity \rho(T) of YBa_2Cu_3O_x (YBCO) and La_(2-x)Sr_xCuO_4 (LSCO) are calculated and compared to experiments. Holes transport was taken in the \tau-approximation, where \tau(T,\epsilon) is due to acoustic phonons. Besides, T-dependence of the chemical potential \mu(T) and effective carrier mass m* ~10-100 free electron masses, obtained by negative-U centers modelling the T-dependence of the Hall coefficient, were used to calculate \rho(T). In addition, it is demonstrated that anisotropy of the cuprates does not affect the calculated T-variation of neither Hall coefficient nor \rho, but only rescale their magnitudes by factors depending on combinations of m_ab and m_c.Comment: 4th International Conference Fundamental Problems of High-Temperature Superconductivity, Moscow-Zvenigorod (October 3-7, 2011) Submitted to J. Supercond. Nov. Magn.: after revision. Extension for Supercond. Sci. Technol. 24 075026 (2011), DOI: 10.1088/0953-2048/24/7/075026 Contains: 2 pages, 3 figure
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