An essential role for c-FLIP in the efficient development of mature T lymphocytes

Apoptosis-related genes play important roles in thymocyte maturation. We show that cellular FLICE-like inhibitory protein (c-FLIP), a procaspase-8–like apoptotic regulator, plays an essential role in the efficient development of mature T lymphocytes. Mice conditionally lacking c-FLIP in T lymphocytes display severe defects in the development of mature T cells, as indicated by a dramatically reduced number of CD4+ and CD8+ T cells in the spleen and lymph nodes of mutant mice. The impaired T lymphocyte maturation in c-FLIP conditional knockout mice occurs at the single-positive thymocyte stage and may be caused by enhanced apoptosis in vivo. Moreover, although c-FLIP has been implicated in T cell receptor signaling through nuclear factor (NF)-κB and Erk pathways, activation of NF-κB and Erk in c-FLIP–deficient thymocytes appears largely intact. Collectively, our data suggest that the primary role of c-FLIP in thymocyte maturation is to protect cells from apoptosis

Probing nuclear symmetry energy at high densities using pion, kaon, eta and photon productions in heavy-ion collisions

The high-density behavior of nuclear symmetry energy is among the most uncertain properties of dense neutron-rich matter. Its accurate determination has significant ramifications in understanding not only the reaction dynamics of heavy-ion reactions especially those induced by radioactive beams but also many interesting phenomena in astrophysics, such as the explosion mechanism of supernova and the properties of neutron stars. The heavy-ion physics community has devoted much effort during the last few years to constrain the high-density symmetry using various probes. In particular, the pion-/pion+ ratio has been most extensively studied both theoretically and experimentally. All models have consistently predicted qualitatively that the pion-/pion+ ratio is a sensitive probe of the high-density symmetry energy especially with beam energies near the pion production threshold. However, the predicted values of the pion-/pion+ ratio are still quite model dependent mostly because of the complexity of modeling pion production and reabsorption dynamics in heavy-ion collisions, leading to currently still controversial conclusions regarding the high-density behavior of nuclear symmetry energy from comparing various model calculations with available experimental data. As more pion-/pion+ data become available and a deeper understanding about the pion dynamics in heavy-ion reactions is obtained, more penetrating probes, such as the kaon+/kaon0 ratio, eta meson and high energy photons are also being investigated or planned at several facilities. Here, we review some of our recent contributions to the community effort of constraining the high-density behavior of nuclear symmetry energy in heavy-ion collisions. In addition, the status of some worldwide experiments for studying the high-density symmetry energy, including the HIRFL-CSR external target experiment (CEE) are briefly introduced.Comment: 10 pages, 10 figures, Contribution to the Topical Issue on Nuclear Symmetry Energy in EPJA Special Volum

FoxM1B transcriptionally regulates vascular endothelial growth factor expression and promotes the angiogenesis and growth of glioma cells.

We previously found that FoxM1B is overexpressed in human glioblastomas and that forced FoxM1B expression in anaplastic astrocytoma cells leads to the formation of highly angiogenic glioblastoma in nude mice. However, the molecular mechanisms by which FoxM1B enhances glioma angiogenesis are currently unknown. In this study, we found that vascular endothelial growth factor (VEGF) is a direct transcriptional target of FoxM1B. FoxM1B overexpression increased VEGF expression, whereas blockade of FoxM1 expression suppressed VEGF expression in glioma cells. Transfection of FoxM1 into glioma cells directly activated the VEGF promoter, and inhibition of FoxM1 expression by FoxM1 siRNA suppressed VEGF promoter activation. We identified two FoxM1-binding sites in the VEGF promoter that specifically bound to the FoxM1 protein. Mutation of these FoxM1-binding sites significantly attenuated VEGF promoter activity. Furthermore, FoxM1 overexpression increased and inhibition of FoxM1 expression suppressed the angiogenic ability of glioma cells. Finally, an immunohistochemical analysis of 59 human glioblastoma specimens also showed a significant correlation between FoxM1 overexpression and elevated VEGF expression. Our findings provide both clinical and mechanistic evidence that FoxM1 contributes to glioma progression by enhancing VEGF gene transcription and thus tumor angiogenesis

J/psi production at mid and forward rapidity at RHIC

We calculate the rapidity dependence of $J/\psi$ nuclear modification factor and averaged transverse momentum square in heavy ion collisions at RHIC in a 3-dimensional transport approach with regeneration mechanism.Comment: 4 pages, 2 figures - To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse

A Study of the Properties of the QCD Phase Diagram in High-Energy Nuclear Collisions

With the aim of understanding the phase structure of nuclear matter created in high-energy nuclear collisions at finite baryon density, a beam energy scan program has been carried out at Relativistic Heavy Ion Collider (RHIC). In this mini-review, most recent experimental results on collectivity, criticality and heavy flavor productions will be discussed. The goal here is to establish the connection between current available data and future heavy-ion collision experiments in a high baryon density region.Comment: Invited review, 30 pages, 18 figure

Space-time Evolution of J/psi Production in High Energy Nuclear Collisions

The space-time evolution of J/psi production in central Au+Au collisions at RHIC energy is investigated in a transport model. Both gluon dissociation and continuous regeneration of J/psis inside deconfined state are considered.Comment: 6 pages, 3 figures, talk at International Conference on Strangeness in Quark Matter 2008, revised version, accepted by Journal of Physics

J/psi Transverse Momentum Distribution in High Energy Nuclear Collisions

The transverse momentum (pt) dependence of J/psi production in heavy ion collisions is investigated in a transport model with both initial production and continuous regeneration of charmonia. The competition between the two production mechanisms results in a pt suppression in central collisions, the gluon multi-scattering in the initial stage leads to a high pt enhancement, and the regeneration populates J/psis at low pt region and induces a minimum in R_AA(pt). These three phenomena are indeed observed in both 200 GeV Cu+Cu and Au+Au collisions at RHIC energy.Comment: 7 pages, 3 figures, final version, accepted by Phys. Lett.