555 research outputs found

    Su alcune piante nuove delle Isole Pelagie

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    On some new plants to Pelagic islands (Straits of Sicily) \u2013 Fifteen vascular plants belonging to the families Aizoaceae, Amaryllidaceae, Asteraceae, Brassicaceae, Euphorbiaceae, Myoporaceae, Orobanchaceae, Oxalidaceae, Portulacaceae and Solanaceae are reported as new to one or both the major Pelagic islands. With the exception of Narcissus serotinus and Orobanche minor, they are non-native plants, probably of recent human introduction, mostly in areas heavily modified by man. Myoporum insulare, widely used for reforestation and for ornament, occurs also in sub and semi-natural environments

    COVID‑19 mitigation by digital contact tracing and contact prevention (app‑based social exposure warnings)

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    A plethora of measures are being combined in the attempt to reduce SARS-CoV-2 spread. Due to its sustainability, contact tracing is one of the most frequently applied interventions worldwide, albeit with mixed results. We evaluate the performance of digital contact tracing for different infection detection rates and response time delays. We also introduce and analyze a novel strategy we call contact prevention, which emits high exposure warnings to smartphone users according to Bluetooth-based contact counting. We model the effect of both strategies on transmission dynamics in SERIA, an agent-based simulation platform that implements population-dependent statistical distributions. Results show that contact prevention remains effective in scenarios with high diagnostic/response time delays and low infection detection rates, which greatly impair the effect of traditional contact tracing strategies. Contact prevention could play a significant role in pandemic mitigation, especially in developing countries where diagnostic and tracing capabilities are inadequate. Contact prevention could thus sustainably reduce the propagation of respiratory viruses while relying on available technology, respecting data privacy, and most importantly, promoting community-based awareness and social responsibility. Depending on infection detection and app adoption rates, applying a combination of digital contact tracing and contact prevention could reduce pandemic-related mortality by 20–56%.publishedVersionFil: Soldano, Germán J. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Soldano, Germán J. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina.Fil: Fraire Juan A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Fraire Juan A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Estudios Avanzados en ingeniería y Tecnología; Argentina.Fil: Fraire Juan A. Saarland University. Saarland Informatics Campus; Saarbrücken, Germany.Fil: Finochietto, Jorge M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Finochietto, Jorge M. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Estudios Avanzados en ingeniería y Tecnología; Argentina.Fil: Quiroga; Rodrigo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina.Fil: Quiroga; Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina

    Adoptively transferred human lung tumor specific cytotoxic T cells can control autologous tumor growth and shape tumor phenotype in a SCID mouse xenograft model

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    <p>Abstract</p> <p>Background</p> <p>The anti-tumor efficacy of human immune effector cells, such as cytolytic T lymphocytes (CTLs), has been difficult to study in lung cancer patients in the clinical setting. Improved experimental models for the study of lung tumor-immune cell interaction as well as for evaluating the efficacy of adoptive transfer of immune effector cells are needed.</p> <p>Methods</p> <p>To address questions related to the <it>in vivo </it>interaction of human lung tumor cells and immune effector cells, we obtained an HLA class I <sup>+ </sup>lung tumor cell line from a fresh surgical specimen, and using the infiltrating immune cells, isolated and characterized tumor antigen-specific, CD8<sup>+ </sup>CTLs. We then established a SCID mouse-human tumor xenograft model with the tumor cell line and used it to study the function of the autologous CTLs provided via adoptive transfer.</p> <p>Results</p> <p>The tumor antigen specific CTLs isolated from the tumor were found to have an activated memory phenotype and able to kill tumor cells in an antigen specific manner <it>in vitro</it>. Additionally, the tumor antigen-specific CTLs were fully capable of homing to and killing autologous tumors <it>in vivo</it>, and expressing IFN-Îł, each in an antigen-dependent manner. A single injection of these CTLs was able to provide significant but temporary control of the growth of autologous tumors <it>in vivo </it>without the need for IL-2. The timing of injection of CTLs played an essential role in the outcome of tumor growth control. Moreover, immunohistochemical analysis of surviving tumor cells following CTL treatment indicated that the surviving tumor cells expressed reduced MHC class I antigens on their surface.</p> <p>Conclusion</p> <p>These studies confirm and extend previous studies and provide additional information regarding the characteristics of CTLs which can be found within a patient's tumor. Moreover, the <it>in vivo </it>model described here provides a unique window for observing events that may also occur in patients undergoing adoptive cellular immunotherapy as effector cells seek and destroy areas of tumor growth and for testing strategies to improve clinical effectiveness.</p

    Structural and mutational analyses of the Leptospira interrogans virulence-related heme oxygenase provide insights into its catalytic mechanism

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    © 2017 Soldano et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Heme oxygenase from Leptospira interrogans is an important virulence factor. During catalysis, redox equivalents are provided to this enzyme by the plastidic-type ferredoxin-NADP+ reductase also found in L. interrogans. This process may have evolved to aid this bacterial pathogen to obtain heme-iron from their host and enable successful colonization. Herein we report the crystal structure of the heme oxygenase-heme complex at 1.73 Å resolution. The structure reveals several distinctive features related to its function. A hydrogen bonded network of structural water molecules that extends from the catalytic site to the protein surface was cleared observed. A depression on the surface appears to be the H+ network entrance from the aqueous environment to the catalytic site for O2 activation, a key step in the heme oxygenase reaction. We have performed a mutational analysis of the F157, located at the above-mentioned depression. The mutant enzymes were unable to carry out the complete degradation of heme to biliverdin since the reaction was arrested at the verdoheme stage. We also observed that the stability of the oxyferrous complex, the efficiency of heme hydroxylation and the subsequent conversion to verdoheme was adversely affected. These findings underscore a long-range communication between the outer fringes of the hydrogen-bonded network of structural waters and the heme active site during catalysis. Finally, by analyzing the crystal structures of ferredoxin-NADP+ reductase and heme oxygenase, we propose a model for the productive association of these proteins

    Ultracompact, low-loss directional couplers on InP based on self-imaging by multimode interference

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    We report extremely compact (494-µm-long 3 dB splitters, including input/output bends), polarization-insensitive, zero-gap directional couplers on InP with a highly multimode interference region that are based on the self-imaging effect. We measured cross-state extinctions better than 28 dB and on-chip insertion losses of 0.5 dB/coupler plus 1 dB/cm guide propagation loss at 1523 nm wavelength
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