The influence of antioxidants and cycloheximide on the level of nitric oxide in the livers of mice in vivo

AbstractWhen injected into mice prior to the NO generation increase induced with lipopolysaccharide (LPS) from Escherichia coli, exogenous antioxidants diethyldithiocarbamate (DETC) or phenazan (sodium 3.5-di-tert-butyl-4-oxiphenylpropionate) as well as the inhibitor of protein biosynthesis, cycloheximide (CHI) attenuated the NO production in mouse liver in vivo. These data demonstrated the key role of free radicals, which were likely, active oxygen species, in the synthesis of inducible NO-synthase (iNOS) responsible for the NO production in this organ. Similar effects of phenazan and CHI were observed in livers of mice treated with γ-irradiation or LPS + Fe2+-citrate, which suggested that these treatments also induced 1NOS synthesis through initiating the action of active oxygen species. The rate of NO synthesis was estimated by accumulation of paramagnetic mononitrosyl iron complexes with DETC (MNIC-DETC) detected using the EPR method. The formation of MNIC-DETC complexes was found in the brain of mice pre-treated with LPS + Fe2+-citrate which seemed to be due to iNOS synthesis stimulated by this treatment

Relativistic Kinetic Equations for Electromagnetic, Scalar and Pseudoscalar Interactions

We derive the kinetic equations for both the covariant and equal-time Wigner functions of Dirac particles with electromagnetic, scalar and pseudoscalar interactions. We emphasize the constraint equations for the spinor components in the equal-time formulation.Comment: 12 pages, no figures, revte

Coherent photon bremsstrahlung and dynamics of heavy-ion collisions: comparison of different models

Differential spectra of coherent photon bremsstrahlung in relativistic heavy ion collisions are calculated within various schematic models of the projectile-target stopping. Two versions of the degradation length model, based on a phenomenological deceleration law, are considered. The simple shock wave model is studied analytically. The predictions of these models agree in the soft photon limit, where the spectrum is determined only by the final velocity distribution of charged particles. The results of these models in the case of central Au+Au collisions at various bombarding energies are compared with the predictions of the microscopic transport model UrQMD. It is shown that at the AGS energy the coherent photon bremsstrahlung exceeds the photon yield from $\pi^0$-decays at photon energies \omega\loo 50 MeV.Comment: 23 pages RevTeX, 9 eps Figure

Color plasma oscillation in strangelets

The dispersion relation and damping rate of longitudinal color plasmons in finite strange quark matter (strangelets) are evaluated in the limits of weak coupling, low temperature, and long wavelength. The property of the QCD vacuum surrounding a strangelet makes the frequency of the plasmons nearly the same as the color plasma frequency of bulk matter. The plasmons are damped by their coupling with individual excitations of particle-hole pairs of quarks, of which the energy levels are discretized by the boundary. For strangelets of macroscopic size, the lifetime of the plasmons is found to be proportional to the size, as in the case of the usual plasma oscillations in metal nanoparticles.Comment: 9 pages (REVTeX), 2 Postscript figures, to be published in Phys. Rev.

Particle Production and Effective Thermalization in Inhomogeneous Mean Field Theory

As a toy model for dynamics in nonequilibrium quantum field theory we consider the abelian Higgs model in 1+1 dimensions with fermions. In the approximate dynamical equations, inhomogeneous classical (mean) Bose fields are coupled to quantized fermion fields, which are treated with a mode function expansion. The effective equations of motion imply e.g. Coulomb scattering, due to the inhomogeneous gauge field. The equations are solved numerically. We define time dependent fermion particle numbers with the help of the single-time Wigner function and study particle production starting from inhomogeneous initial conditions. The particle numbers are compared with the Fermi-Dirac distribution parametrized by a time dependent temperature and chemical potential. We find that the fermions approximately thermalize locally in time.Comment: 16 pages + 6 eps figures, some clarifications and two references added, typos corrected; to appear in Phys.Rev.

Physics and Astrophysics of Strange Quark Matter

3-flavor quark matter (strange quark matter; SQM) can be stable or metastable for a wide range of strong interaction parameters. If so, SQM can play an important role in cosmology, neutron stars, cosmic ray physics, and relativistic heavy-ion collisions. As an example of the intimate connections between astrophysics and heavy-ion collision physics, this Chapter gives an overview of the physical properties of SQM in bulk and of small-baryon number strangelets; discusses the possible formation, destruction, and implications of lumps of SQM (quark nuggets) in the early Universe; and describes the structure and signature of strange stars, as well as formation and detection of strangelets in cosmic rays. It is concluded, that astrophysical and laboratory searches are complementary in many respects, and that both should be pursued to test the intriguing possibility of a strange ground state for hadronic matter, and (more generally) to improve our knowledge of the strong interactions.Comment: 45 pages incl. figures. To appear in "Hadrons in Dense Matter and Hadrosynthesis", Lecture Notes in Physics, Springer Verlag (ed. J.Cleymans

Thermal charm production by massive gluons and quarks

We investigate charm production in an equilibrated quark-gluon plasma produced in heavy-ion collisions at RHIC and LHC. Effective quark and gluon masses are introduced from thermal QCD calculations. Assuming a Bjorken-type longitudinal expansion and including the influence of temperature dependent masses on the expansion, we determine the total number of c\bar{c} pairs produced in the quark-gluon plasma phase. We calculate the charm production rate at leading order with massive gluons and quarks and compare our result to charm production by massless partons. We consider two different scenarios for the initial conditions, a parton gas with a rather long kinetic equilibration time and a minijet gas with a short equilibration time. In a parton gas, assuming m_c=1.2 GeV, we obtain a substantial enhancement over the thermal charm rate from massless quarks and gluons, up to 4.9 secondary charm quark pairs in Au+Au collisions at RHIC and 245 charm pairs in Pb+Pb collisions at the LHC.Comment: 19 pages in Latex and 9 Postscript figure