Correlation and Dimerization Effects on the Physical Behavior of the NR4[Ni(dmit)2]2NR_4 [Ni(dmit)_2]_2 Charge Transfer Salts : A DMRG Study of the Quarter-Filling t-J Model

The present work studies the quasi one-dimensional $Ni(dmit)_2$-based compounds within a correlated model. More specifically, we focus our attention on the composed influence of the electronic dimerization-factor and the repulsion, on the transport properties and the localization of the electronic density in the ground-state. Those properties are studied through the computation of the charge gaps (difference between the ionization potential and the electro-affinity: IP-EA) and the long- and short-bond orders of an infinite quarter-filled chain within a $t-J(t,U)$ model. The comparison between the computed gaps and the experimental activation energy of the semiconductor $NH_2Me_2 [Ni(dmit)_2]_2$ allows us to estimate the on-site electronic repulsion of the $Ni(dmit)_2$ molecule to $1.16eV$.Comment: 13 pages, 4 figures, RevTe

Resident macrophages influence stem cell activity in the mammary gland

Introduction Macrophages in the mammary gland are essential for morphogenesis of the ductal epithelial tree and have been implicated in promoting breast tumor metastasis. Although it is well established that macrophages influence normal mammopoiesis, the mammary cell types that these accessory cells influence have not been determined. Here we have explored a role for macrophages in regulating mammary stem cell (MaSC) activity, by assessing the ability of MaSCs to reconstitute a mammary gland in a macrophage-depleted fat pad. Methods Two different in vivo models were used to deplete macrophages from the mouse mammary fat pad, allowing us to examine the effect of macrophage deficiency on the mammary repopulating activity of MaSCs. Both the Csf1(op/op) mice and clodronate liposome-mediated ablation models entailed transplantation studies using the MaSC-enriched population. Results We show that mammary repopulating ability is severely compromised when the wild-type MaSC-enriched subpopulation is transplanted into Csf1(op/op) fat pads. In reciprocal experiments, the MaSC-enriched subpopulation from Csf1(op/op) glands had reduced regenerative capacity in a wildtype environment. Utilizing an alternative strategy for selective depletion of macrophages from the mammary gland, we demonstrate that co-implantation of the MaSC-enriched subpopulation with clodronate-liposomes leads to a marked decrease in repopulating frequency and outgrowth potential. Conclusions Our data reveal a key role for mammary gland macrophages in supporting stem/progenitor cell function and suggest that MaSCs require macrophage-derived factors to be fully functional. Macrophages may therefore constitute part of the mammary stem cell nich

Destruction of tumor vasculature and abated tumor growth upon VEGF blockade is driven by proapoptotic protein Bim in endothelial cells

VEGF deprivation induces Bim expression in tumor endothelial cells, and Bim is needed for anti-VEGF–driven endothelial cell death and tumor shrinkage

Transcriptome analyses of mouse and human mammary cell subpopulations reveal multiple conserved genes and pathways

INTRODUCTION: Molecular characterization of the normal epithelial cell types that reside in the mammary gland is an important step toward understanding pathways that regulate self-renewal, lineage commitment, and differentiation along the hierarchy. Here we determined the gene expression signatures of four distinct subpopulations isolated from the mouse mammary gland. The epithelial cell signatures were used to interrogate mouse models of mammary tumorigenesis and to compare with their normal human counterpart subsets to identify conserved genes and networks. METHODS: RNA was prepared from freshly sorted mouse mammary cell subpopulations (mammary stem cell (MaSC)-enriched, committed luminal progenitor, mature luminal and stromal cell) and used for gene expression profiling analysis on the Illumina platform. Gene signatures were derived and compared with those previously reported for the analogous normal human mammary cell subpopulations. The mouse and human epithelial subset signatures were then subjected to Ingenuity Pathway Analysis (IPA) to identify conserved pathways. RESULTS: The four mouse mammary cell subpopulations exhibited distinct gene signatures. Comparison of these signatures with the molecular profiles of different mouse models of mammary tumorigenesis revealed that tumors arising in MMTV-Wnt-1 and p53-/- mice were enriched for MaSC-subset genes, whereas the gene profiles of MMTV-Neu and MMTV-PyMT tumors were most concordant with the luminal progenitor cell signature. Comparison of the mouse mammary epithelial cell signatures with their human counterparts revealed substantial conservation of genes, whereas IPA highlighted a number of conserved pathways in the three epithelial subsets. CONCLUSIONS: The conservation of genes and pathways across species further validates the use of the mouse as a model to study mammary gland development and highlights pathways that are likely to govern cell-fate decisions and differentiation. It is noteworthy that many of the conserved genes in the MaSC population have been considered as epithelial-mesenchymal transition (EMT) signature genes. Therefore, the expression of these genes in tumor cells may reflect basal epithelial cell characteristics and not necessarily cells that have undergone an EMT. Comparative analyses of normal mouse epithelial subsets with murine tumor models have implicated distinct cell types in contributing to tumorigenesis in the different models

From Theory to Engineering to Practivce

International audienc

Physical Multiscale Modeling and Numerical Simulation of Electrochemical Devices for Energy Conversion and Storage From Theory to Engineering to Practice Preface

International audienc

Physical Multiscale Modeling and Numerical Simulation of Electrochemical Devices for Energy Conversion and Storage From Theory to Engineering to Practice Preface

International audienc

Physical Multiscale Modeling and Numerical Simulation of Electrochemical Devices for Energy Conversion and Storage From Theory to Engineering to Practice Preface

International audienc