1,069 research outputs found

    Experimental behaviour of a steel structure under natural fire

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    Current design codes for fire resistance of structures are based on isolated member tests subjected to standard fire conditions. Such tests do not reflect the behaviour of a complete building under either normal temperature or fire conditions. Many aspects of behaviour occur due to the interaction between members and cannot be predicted or observed in tests of isolated elements. Performance of real structures subject to real fires is often much better than that predicted from standard tests due to structural continuity and the provision of alternative load paths.http://www.sciencedirect.com/science/article/B6V37-4KN5C4D-1/1/8f781d0c96159d54029bef7c9ec451b

    Experimental behaviour of a steel structure under natural fire

    Get PDF
    Current design codes for fire resistance of structures are based on isolated member tests subjected to standard fire conditions. Such tests do not reflect the behaviour of a complete building under either normal temperature or fire conditions. Many aspects of behaviour occur due to the interaction between members and cannot be predicted or observed in tests of isolated elements. Performance of real structures subject to real fires is often much better than that predicted from standard tests due to structural continuity and the provision of alternative load paths.http://www.sciencedirect.com/science/article/B6V37-4KN5C4D-1/1/8f781d0c96159d54029bef7c9ec451b

    Tumor Cell–Intrinsic c-Myb Upregulation Stimulates Antitumor Immunity in a Murine Colorectal Cancer Model

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    The transcription factor c-Myb is overexpressed in many different types of solid tumors, including colorectal cancer. However, its exact role in tumorigenesis is unclear. In this study, we show that tumor-intrinsic c-Myb expression in mouse models of colon cancer and melanoma suppresses tumor growth. Although no differences in proliferation, apoptosis, and angiogenesis of tumors were evident in tumors with distinct levels of c-Myb expression, we observed changes in intratumoral immune cell infiltrates. MC38 tumors with upregulated c-Myb expression showed increased numbers of CD103+ dendritic cells and eosinophils, but decreased tumor-associated macrophages (TAM). Concomitantly, an increase in the number of activated cytotoxic CD8+ T cells upon c-Myb upregulation was observed, which correlated with a pro-inflammatory tumor microenvironment and increased numbers of M1 polarized TAMs. Mechanistically, c-Myb upregulation in immunogenic MC38 colon cancer cells resulted in enhanced expression of immunomodulatory genes, including those encoding β2-microglobulin and IFNβ, and decreased expression of the gene encoding the chemokine receptor CCR2. The increased numbers of activated cytotoxic CD8+ T cells contributed to tumor growth attenuation. In poorly immunogenic CT26, LLC, and B16-BL6 tumor cells, c-Myb upregulation did not affect the immunomodulatory gene expression. Despite this, c-Myb upregulation led to reduced B16-BL6 tumor growth but it did not affect tumor growth of CT26 and LLC tumors. Altogether, we postulate that c-Myb functions as a tumor suppressor in a tumor cell–type specific manner and modulates antitumor immunity

    Lymphocyte gene expression signatures from patients and mouse models of hereditary hemochromatosis reveal a function of HFE as a negative regulator of CD8+ T-lymphocyte activation and differentiation in vivo

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    Abnormally low CD8+ T-lymphocyte numbers is characteristic of some patients with hereditary hemochromatosis (HH), a MHC-linked disorder of iron overload. Both environmental and genetic components are known to influence CD8+ T-lymphocyte homeostasis but the role of the HH associated protein HFE is still insufficiently understood. Genome-wide expression profiling was performed in peripheral blood CD8+ T lymphocytes from HH patients selected according to CD8+ T-lymphocyte numbers and from Hfe-/- mice maintained either under normal or high iron diet conditions. In addition, T-lymphocyte apoptosis and cell cycle progression were analyzed by flow cytometry in HH patients. HH patients with low CD8+ T-lymphocyte numbers show a differential expression of genes related to lymphocyte differentiation and maturation namely CCR7, LEF1, ACTN1, NAA50, P2RY8 and FOSL2, whose expression correlates with the relative proportions of naĂŻve, central and effector memory subsets. In addition, expression levels of LEF1 and P2RY8 in memory cells as well as the proportions of CD8+ T cells in G2/M cell cycle phase are significantly different in HH patients compared to controls. Hfe-/- mice do not show alterations in CD8+ T-lymphocyte numbers but differential gene response patterns. We found an increased expression of S100a8 and S100a9 that is most pronounced in high iron diet conditions. Similarly, CD8+ T lymphocytes from HH patients display higher S100a9 expression both at the mRNA and protein level. Altogether, our results support a role for HFE as a negative regulator of CD8+ T-lymphocyte activation. While the activation markers S100a8 and S100a9 are strongly increased in CD8+ T cells from both, Hfe-/- mice and HH patients, a differential profile of genes related to differentiation/maturation of CD8+ T memory cells is evident in HH patients only. This supports the notion that HFE contributes, at least in part, to the generation of low peripheral blood CD8+ T lymphocytes in HH
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