80 research outputs found

    Plasmons in layered structures including graphene

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    We investigate the optical properties of layered structures with graphene at the interface for arbitrary linear polarization at finite temperature including full retardation by working in the Weyl gauge. As a special case, we obtain the full response and the related dielectric function of a layered structure with two interfaces. We apply our results to discuss the longitudinal plasmon spectrum of several single and double layer devices such as systems with finite and zero electronic densities. We further show that a nonhomogeneous dielectric background can shift the relative weight of the in-phase and out-of-phase mode and discuss how the plasmonic mode of the upper layer can be tuned into an acoustic mode with specific sound velocity.Comment: 18 pages, 6 figure

    Type-Decomposition of a Pseudo-Effect Algebra

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    The theory of direct decomposition of a centrally orthocomplete effect algebra into direct summands of various types utilizes the notion of a type-determining (TD) set. A pseudo-effect algebra (PEA) is a (possibly) noncommutative version of an effect algebra. In this article we develop the basic theory of centrally orthocomplete PEAs, generalize the notion of a TD set to PEAs, and show that TD sets induce decompositions of centrally orthocomplete PEAs into direct summands.Comment: 18 page

    The Immune Inhibitory Receptor LAIR-1 Is Highly Expressed by Plasmacytoid Dendritic Cells and Acts Complementary with NKp44 to Control IFNα Production

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    Plasmacytoid dendritic cells (pDCs) are a subset of dendritic cells endowed with the capacity of producing large amounts of IFNα. Here we show that the Leukocyte-Associated Ig-like Receptor-1 (LAIR-1) is abundantly expressed on pDCs (the highest expression among all leukocytes) and its cross-linking inhibits IFNα production in response to Toll-like receptor ligands. Remarkably, LAIR-1 expression in pDCs is down-regulated in the presence of interleukin (IL)-3, thus indicating coordinated functions with NKp44, another pDC inhibitory receptor, which is conversely induced by IL-3. Nevertheless, the expression of NKp44 in pDCs isolated from secondary lymphoid organs, which is thought to be influenced by IL-3, is not coupled to a decreased expression of LAIR-1. Interestingly, pDCs isolated from peripheral blood of systemic lupus erithematosus (SLE) patients express lower levels of LAIR-1 while displaying slight but consistent expression of NKp44, usually undetectable on pDCs derived from healthy donors. Using sera derived from SLE patients, we show that LAIR-1 and NKp44 display synergistic inhibitory effects on IFNα production by interleukin IL-3 cultured pDCs stimulated with DNA immunocomplexes. In conclusion, our results indicate that the inhibitory function of LAIR-1 may play a relevant role in the mechanisms controlling IFNα production by pDCs both in normal and pathological innate immune responses

    The Tissue Microlocalisation and Cellular Expression of CD163, VEGF, HLA-DR, iNOS, and MRP 8/14 Is Correlated to Clinical Outcome in NSCLC

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    BACKGROUND: We have previously investigated the microlocalisation of M1 and M2 macrophages in NSCLC. This study investigated the non-macrophage (NM) expression of proteins associated with M1 and M2 macrophages in NSCLC. METHODS: Using immunohistochemistry, CD68(+) macrophages and proteins associated with either a cytotoxic M1 phenotype (HLA-DR, iNOS, and MRP 8/14), or a non-cytotoxic M2 phenotype (CD163 and VEGF) were identified. NM expression of the markers was analysed in the islets and stroma of surgically resected tumours from 20 patients with extended survival (ES) (median 92.7 months) and 20 patients with poor survival (PS) (median 7.7 months). RESULTS: The NM expression of NM-HLA-DR (p<0.001), NM-iNOS (p = 0.02) and NM-MRP 8/14 (p = 0.02) was increased in ES compared to PS patients in the tumour islets. The tumour islet expression of NM-VEGF, was decreased in ES compared to PS patients (p<0.001). There was more NM-CD163 expression (p = 0.04) but less NM-iNOS (p = 0.002) and MRP 8/14 (p = 0.01) expression in the stroma of ES patients compared with PS patients. The 5-year survival for patients with above and below median NM expression of the markers in the islets was 74.9% versus 4.7% (NM-HLA-DR p<0.001), 65.0% versus 14.6% (NM-iNOS p = 0.003), and 54.3% versus 22.2% (NM-MRP 8/14 p = 0.04), as opposed to 34.1% versus 44.4% (NM-CD163 p = 0.41) and 19.4% versus 59.0% (NM-VEGF p = 0.001). CONCLUSIONS: Cell proteins associated with M1 and M2 macrophages are also expressed by other cell types in the tumour islets and stroma of patients with NSCLC. Their tissue and cellular microlocalisation is associated with important differences in clinical outcome

    NK Cell Terminal Differentiation: Correlated Stepwise Decrease of NKG2A and Acquisition of KIRs

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    BACKGROUND: Terminal differentiation of NK cells is crucial in maintaining broad responsiveness to pathogens and discriminating normal cells from cells in distress. Although it is well established that KIRs, in conjunction with NKG2A, play a major role in the NK cell education that determines whether cells will end up competent or hyporesponsive, the events underlying the differentiation are still debated. METHODOLOGY/PRINCIPAL FINDINGS: A combination of complementary approaches to assess the kinetics of the appearance of each subset during development allowed us to obtain new insights into these terminal stages of differentiation, characterising their gene expression profiles at a pan-genomic level, their distinct surface receptor patterns and their prototypic effector functions. The present study supports the hypothesis that CD56dim cells derive from the CD56bright subset and suggests that NK cell responsiveness is determined by persistent inhibitory signals received during their education. We report here the inverse correlation of NKG2A expression with KIR expression and explore whether this correlation bestows functional competence on NK cells. We show that CD56dimNKG2A-KIR+ cells display the most differentiated phenotype associated to their unique ability to respond against HLA-E+ target cells. Importantly, after IL-12+IL-18 stimulation, reacquisition of NKG2A strongly correlates with IFN-gamma production in CD56dimNKG2A- NK cells. CONCLUSIONS/SIGNIFICANCE: Together, these findings call for the reclassification of mature human NK cells into distinct subsets and support a new model, in which the NK cell differentiation and functional fate are based on a stepwise decrease of NKG2A and acquisition of KIRs

    Guards at the gate: physiological and pathological roles of tissue-resident innate lymphoid cells in the lung

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    Emergência de plântulas de espécies silvestres de amendoim.

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    O objetivo deste trabalho foi avaliar, após dois períodos de armazenamento, o poder germinativo de sementes de espécies silvestres de amendoim, sob a influência do tratamento com etileno e do descascamento manual dos frutos. O ensaio foi realizado em laboratório do Pólo Apta Centro Norte, em Pindorama, SP. Amostras de sementes de acessos das espécies Arachis stenosperma, A. kuhlmannii, A. monticola, A. gregoryi e A. williamsii foram utilizadas no ensaio. As sementes foram descascadas ou não (retirada do pericarpo), e submetidas ou não ao etileno para quebra da dormência depois de submetidos ao armazenamento em condições ambientais por 130 e 500 dias após a colheita (DAC). Todos os acessos apresentaram maior germinação quando submetidos ao tratamento com etileno, indicando a existência de dormência nas sementes, principalmente no período de 130 dias de armazenamento em condições naturais. As sementes de A. monticola apresentaram significativa dormência mesmo após 500 dias de armazenamento em condições naturais. As sementes silvestres responderam de forma diferente quanto à capacidade de germinação após a retirada do pericarpo, mas aos 130 dias, apresentam, no geral, maior teor germinativo sem o pericarpo; entretanto, com o longo tempo de armazenamento, tornam-se aparentemente sensíveis ao descascamento, germinando melhor com o pericarpo
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