274 research outputs found

    On the simplicial volumes of fibre bundles

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    We show that surface bundles over surfaces with base and fiber of genus at least 2 have non-vanishing simplicial volume.Comment: 4 pages, revised version, one reference added, to appear in the Proceedings of the AM

    The Effects of a Six-Week HIIT Program on CVD Risk Factors in Sedentary Individuals

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    Please see the pdf version of the abstract

    Current density distribution in cylindrical Li-Ion cells during impedance measurements

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    In this work, modified commercial cylindrical lithium-ion cells with multiple separate current tabs are used to analyze the influence of tab pattern, frequency and temperature on electrochemical impedance spectroscopy. In a first step, the effect of different current tab arrangements on the impedance spectra is analyzed and possible electrochemical causes are discussed. In a second step, one terminal is used to apply a sinusoidal current while the other terminals are used to monitor the local potential distribution at different positions along the electrodes of the cell. It is observed that the characteristic decay of the voltage amplitude along the electrode changes non-linearly with frequency, where high-frequent currents experience a stronger attenuation along the current collector than low-frequent currents. In further experiments, the decay characteristic is controlled by the cell temperature, driven by the increasing resistance of the current collector and the enhanced kinetic and transport properties of the active material and electrolyte. Measurements indicate that the ac current distribution depends strongly on the frequency and the temperature. In this context, the challenges for electrochemical impedance spectroscopy as cell diagnostic technique for commercial cells are discussed

    Effect of temperature on the kinetics of electrochemical insertion of li-ions into a graphite electrode studied by kinetic Monte Carlo

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    The effect of temperature on the kinetics of electrochemical insertion/removal of lithium in graphite is analyzed by kinetic Monte Carlo methods. Different electrochemical techniques are simulated at different temperatures and responses are compared with experimental results. Simulated voltammograms show, similarly to experiment, how the behavior of the system becomes closer to equilibrium as temperature increases. Calculated chronoamperometric profiles show a different qualitative behavior in the current at different temperatures, especially in the Cottrell representation peaks, explained in terms of the relative importance of diffusive versus charge transfer processes at different temperatures. Results at room temperature are in good agreement with experiment, and we further evaluate trends at elevated temperature that have not yet been described in experimental or theoretical works. Exchange current densities for different degrees of lithium intercalation at different temperatures are predicted using potentiostatic simulations, showing an Arrhenius-type relationship. The dependence of the exchange current on electrolyte composition is simulated by investigating the effect of different activation energy barriers at different temperatures. The influence of temperature on diffusion coefficients as a function of lithiation fraction in graphite is simulated and related to Arrhenius plots, explaining the experimentally observed changes in diffusion phenomena with lithium composition and temperature.Fil: Gavilán Arriazu, Edgardo Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. Universidad Nacional de Santiago del Estero. Instituto de Bionanotecnología del Noa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Bionanotecnología del Noa; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Teórica y Computacional; ArgentinaFil: Mercer, Michael. Centre National de la Recherche Scientifique; Francia. Lancaster University. Department of Chemistry; Reino Unido. ALISTORE European Research Institute; Francia. The Faraday Institution; Reino UnidoFil: Pinto, Oscar Alejandro. Universidad Nacional de Santiago del Estero. Instituto de Bionanotecnología del Noa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Bionanotecnología del Noa; ArgentinaFil: Oviedo, Oscar Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Barraco Diaz, Daniel Eugenio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Hoster, Harry Ernst. Centre National de la Recherche Scientifique; Francia. Lancaster University. Department of Chemistry; Reino Unido. ALISTORE European Research Institute; Francia. The Faraday Institution; Reino UnidoFil: Leiva, Ezequiel Pedro M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Teórica y Computacional; Argentin

    Numerical simulations of cyclic voltammetry for lithium-ion intercalation in nanosized systems: Finiteness of diffusion versus electrode kinetics

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    The voltammetric behavior of Li+ intercalation/deintercalation in/from LiMn2O4 thin films and single particles is simulated, supporting very recent experimental results. Experiments and calculations both show that particle size and geometry are crucial for the electrochemical response. A remarkable outcome of this research is that higher potential sweep rates, of the order of several millivolts per second, may be used to characterize nanoparticles by voltammetry sweeps, as compared with macroscopic systems. This is in line with previous conclusions drawn for related single particle systems using kinetic Monte Carlo simulations. The impact of electrode kinetics and finite space diffusion on the reversibility of the process and the finiteness of the diffusion in ion Li / LiMn2O4 (de)intercalation is also discussed in terms of preexisting modeling.Fil: Gavilán Arriazu, Edgardo Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Mercer, M.P.. Lancaster University; Reino UnidoFil: Pinto, Oscar Alejandro. Universidad Nacional de Santiago del Estero. Instituto de Bionanotecnología del Noa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Bionanotecnología del Noa; ArgentinaFil: Oviedo, Oscar Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Barraco Diaz, Daniel Eugenio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Hoster, H. E.. Lancaster University; Reino UnidoFil: Leiva, Ezequiel Pedro M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentin

    Engendering Unprecedented Activation of Oxygen Evolution via Rational Pinning of Ni Oxidation State in Prototypical Perovskite:Close Juxtaposition of Synthetic Approach and Theoretical Conception

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    Rational optimization of the OER activity of catalysts based on LaNiO3 oxide is achieved by maximizing the presence of trivalent Ni in the surface structure. DFT investigations of the LaNiO3 catalyst and surface structures related to it predict an improvement in the OER activity for these materials to levels comparable with the top of the OER volcano if the La content is minimized while the oxidation state of Ni is maintained. These theoretically predicted structures of high intrinsic OER activity can be prepared by a templated spray-freeze freeze-drying synthesis followed by a simple postsynthesis exfoliation-like treatment in acidic media. These nanocrystalline LaNiO3-related materials confirm the theoretical predictions, showing a dramatic improvement in OER activity. The exfoliated surfaces remain stable in OER catalysis, as shown by an in-operando ICP-OES study. The unprecedented OER activation of the synthesized LaNiO3-based materials is related to a close juxtaposition of the theoretical conception of ideal structural motifs and the ability to engender such motifs using a unique synthetic procedure, both principally related to stabilization and pinning of the Ni oxidation state within the local coordination environment of the perovskite structure. © 2021 American Chemical Society. All rights reserved

    B-cell receptor-driven MALT1 activity regulates MYC signaling in mantle cell lymphoma.

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    Mantle cell lymphoma (MCL) is a mature B-cell lymphoma characterized by poor clinical outcome. Recent studies revealed the importance of B-cell receptor (BCR) signaling in maintaining MCL survival. However, it remains unclear which role MALT1, an essential component of the CARD11-BCL10-MALT1 complex that links BCR signaling to the NF-κB pathway, plays in the biology of MCL. Here we show that a subset of MCLs is addicted to MALT1, as its inhibition by either RNA or pharmacologic interference induced cytotoxicity both in vitro and in vivo. Gene expression profiling following MALT1 inhibition demonstrated that MALT1 controls an MYC-driven gene expression network predominantly through increasing MYC protein stability. Thus, our analyses identify a previously unappreciated regulatory mechanism of MYC expression. Investigating primary mouse splenocytes, we could demonstrate that MALT1-induced MYC regulation is not restricted to MCL, but represents a common mechanism. MYC itself is pivotal for MCL survival because its downregulation and pharmacologic inhibition induced cytotoxicity in all MCL models. Collectively, these results provide a strong mechanistic rationale to investigate the therapeutic efficacy of targeting the MALT1-MYC axis in MCL patients

    Креативность как личностное качество обучающихся сквозь призму самоанализа

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    The focus of this study was to assess exercise-induced alterations of circulating dendritic cell (DC) subpopulations and toll-like receptor (TLR) expression after marathon running. Blood sampling was performed in 15 obese non-elite (ONE), 16 lean non-elite (LNE) and 16 lean elite (LE) marathon runners pre- and post-marathon as well as 24 h after the race. Circulating DC-fractions were measured by flow-cytometry analyzing myeloid DCs (BDCA-1+) and plasmacytoid DCs (BDCA-2+). We further analyzed the (TLR) -2/-4/-7 in peripheral blood mononuclear cells (rt-PCR/Western Blot) and the cytokines CRP, IL-6, IL-10, TNF-α and oxLDL by ELISA. After the marathon, BDCA-1 increased significantly in all groups [LE (pre/post): 0.35/0.47%; LNE: 0.26/0.50% and ONE: 0.30/0.49%; all p < 0.05]. In contrast, we found a significant decrease for BDCA-2 directly after the marathon (LE: 0.09/0.01%; LNE: 0.12/0.03% and ONE: 0.10/0.02%; all p < 0.05). Levels of TLR-7 mRNA decreased in all groups post-marathon (LE 44%, LNE 67% and ONE 52%; all p < 0.01), with a consecutive protein reduction (LE 31%, LNE 52%, ONE 42%; all p < 0.05) 24 h later. IL-6 and IL-10 levels increased immediately after the run, whereas increases of TNF-α and CRP-levels were seen after 24 h. oxLDL levels remained unchanged post-marathon. In our study population, we did not find any relevant differences regarding training level or body weight. Prolonged endurance exercise induces both pro- and anti-inflammatory cytokines. Anti-inflammatory cytokines, such as IL-10, may help to prevent excessive oxidative stress. Marathon running is associated with alterations of DC subsets and TLR-expression independent of training level or body weight. Myeloid and plasmacytoid DCs are differently affected by the excessive physical stress. Immunomodulatory mechanisms seem to play a key role in the response and adaptation to acute excessive exercise

    20 autores del siglo XX : interpretación y comentario de textos literarios

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    [ES]Son cuatro volúmenes que presentan 20 unidades para la interpretación y comentario de textos literarios de teatro, poesía y narrativa en la materia de literatura en segundo ciclo de la ESO. La estructura de las unidades es la siguiente: texto, guía didáctica (objetivos, contenidos, evaluación, bibliografía y temporalización), aproximación al texto, consideraciones generales sobre el autor y la obra y actividades
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