Role of heparan sulfate for attachment and entry of tick-borne encephalitis virus

AbstractAttachment of the flavivirus tick-borne encephalitis (TBE) virus to different permissive cell lines was investigated by a newly established quantitative assay using fluorescence-labeled virus. Previous work had shown that BHK-21 cell-adapted mutants of TBE virus had acquired potential heparan sulfate (HS) binding sites on the outer surface of protein E. Quantitative analysis of one of these mutants indicated that it attached to HS-expressing cell lines with a 10- to 13-fold higher affinity than wild-type TBE virus strain Neudoerfl. CHO cells deficient in HS synthesis bound less than 5% of the amount of wild-type or mutant virus that could attach to HS-containing CHO cells but were nevertheless found to be highly susceptible to infection with both viruses. Thus, even though HS is a major determinant of TBE virus attachment on HS-expressing cells, our findings suggest the existence of an alternative host cell receptor that is less abundant than HS

Partonic effects on anisotropic flows at RHIC

We report recent results from a multiphase transport (AMPT) model on the azimuthal anisotropies of particle momentum distributions in heavy ion collisions at the Relativistic Heavy Ion Collider. These include higher-order anisotropic flows and their scaling, the rapidity dependence of anisotropic flows, and the elliptic flow of charm quarks.Comment: 7 pages, 5 figures, talk given at "Hot Quarks 2004", July 18-24, 2004, Taos Valley, NM, US

A study on the anomaly of pp over π\pi ratios in Au+AuAu+Au collisions with jet quenching

The ratios of $p/\pi$ at large transverse momentum in central $Au+Au$ collisions at RHIC are studied in the framework of jet quenching based on a next-to-leading order pQCD parton model. It is shown that theoretical calculations with a gluon energy loss larger than the quark energy loss will naturally lead to a smaller $p/\pi$ ratios at large transverse momentum in $Au+Au$ collisions than those in $p+p$ collisions at the same energy. Scenarios with equal energy losses for gluons and quarks and a strong jet conversion are both explored and it is demonstrated in both scenarios $p/\pi$ ratios at high $p_T$ in central $Au+Au$ collisions are enhanced and the calculated ratios of protons over pions approach to the experimental measurements. However, ${\bar p}/p$ in the latter scenario is found to fit data better than that in the former scenario.Comment: 20 pages, 13 figures; revised version; accepted for publication in Journal of Physics

The role of inhibitory feedback for information processing in thalamocortical circuits

The information transfer in the thalamus is blocked dynamically during sleep, in conjunction with the occurence of spindle waves. As the theoretical understanding of the mechanism remains incomplete, we analyze two modeling approaches for a recent experiment by Le Masson {\sl et al}. on the thalamocortical loop. In a first step, we use a conductance-based neuron model to reproduce the experiment computationally. In a second step, we model the same system by using an extended Hindmarsh-Rose model, and compare the results with the conductance-based model. In the framework of both models, we investigate the influence of inhibitory feedback on the information transfer in a typical thalamocortical oscillator. We find that our extended Hindmarsh-Rose neuron model, which is computationally less costly and thus siutable for large-scale simulations, reproduces the experiment better than the conductance-based model. Further, in agreement with the experiment of Le Masson {\sl et al}., inhibitory feedback leads to stable self-sustained oscillations which mask the incoming input, and thereby reduce the information transfer significantly.Comment: 16 pages, 15eps figures included. To appear in Physical Review

Linking Dynamical and Thermal Models of Ultrarelativistic Nuclear Scattering

To analyse ultrarelativistic nuclear interactions, usually either dynamical models like the string model are employed, or a thermal treatment based on hadrons or quarks is applied. String models encounter problems due to high string densities, thermal approaches are too simplistic considering only average distributions, ignoring fluctuations. We propose a completely new approach, providing a link between the two treatments, and avoiding their main shortcomings: based on the string model, connected regions of high energy density are identified for single events, such regions referred to as quark matter droplets. Each individual droplet hadronizes instantaneously according to the available n-body phase space. Due to the huge number of possible hadron configurations, special Monte Carlo techniques have been developed to calculate this disintegration.Comment: Complete paper enclosed as postscript file (uuencoded

Pair correlations in nuclei involved in neutrinoless double beta decay: 76Ge and 76Se

Precision measurements were carried out to test the similarities between the ground states of 76Ge and 76Se. The extent to which these two nuclei can be characterized as consisting of correlated pairs of neutrons in a BCS-like ground state was studied. The pair removal (p,t) reaction was measured at the far forward angle of 3 degrees. The relative cross sections are consistent (at the 5% level) with the description of these nuclei in terms of a correlated pairing state outside the N=28 closed shells with no pairing vibrations. Data were also obtained for 74Ge and 78Se

Kinetic Equation for Gluons in the Background Gauge of QCD

We derive the quantum kinetic equation for a pure gluon plasma, applying the background field and closed-time-path method. The derivation is more general and transparent than earlier works. A term in the equation is found which, as in the classical case, corresponds to the color charge precession for partons moving in the gauge field.Comment: RevTex 4, 4 pages, no figure, PRL accepted versio

Nuclear Physics Experiments with Ion Storage Rings

In the last two decades a number of nuclear structure and astrophysics experiments were performed at heavy-ion storage rings employing unique experimental conditions offered by such machines. Furthermore, building on the experience gained at the two facilities presently in operation, several new storage ring projects were launched worldwide. This contribution is intended to provide a brief review of the fast growing field of nuclear structure and astrophysics research at storage rings.Comment: XVIth International Conference on Electro-Magnetic Isotope Separators and Techniques Related to their Applications, December 2--7, 2012 at Matsue, Japa

Yang-Mills Radiation in Ultra-relativistic Nuclear Collisions

The classical Yang-Mills radiation computed in the McLerran-Venugopalan model is shown to be equivalent to the gluon bremsstrahlung distribution to lowest order in pQCD. The classical distribution is also shown to match smoothly onto the conventional pQCD mini-jet distribution at a scale characteristic of the initial parton transverse density of the system. The atomic number and energy dependence of that scale is computed from available structure function information. The limits of applicability of the classical Yang-Mills description of nuclear collisions at RHIC and LHC energies are discussed.Comment: 21 pages (Latex) including 2 postscript figures via psfi

Decay modes of 250No

The Fragment Mass Analyzer at the ATLAS facility has been used to unambiguously identify the mass number associated with different decay modes of the nobelium isotopes produced via 204Pb(48Ca,xn)(252-x)No reactions. Isotopically pure (>99.7%) 204Pb targets were used to reduce background from more favored reactions on heavier lead isotopes. Two spontaneous fission half-lives (t_1/2 = 3.7+1.1-0.8 us and 43+22-15 us) were deduced from a total of 158 fission events. Both decays originate from 250No rather than from neighboring isotopes as previously suggested. The longer activity most likely corresponds to a K-isomer in this nucleus. No conclusive evidence for an alpha branch was observed, resulting in upper limits of 2.1% for the shorter lifetime and 3.4% for the longer activity.Comment: RevTex4, 10 pages, 5 figures, submitted to PR