393 research outputs found
Case Report: Penile Fracture from Entrapment of an Erect Penis in the African Bamboo Bed: A Case Report
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
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
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
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''
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
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
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
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 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 YBaCuO and LaSrCuO
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
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