513 research outputs found

    Growth-induced electron mobility enhancement at the LaAlO3_3/SrTiO3_3 interface

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    We have studied the electronic properties of the 2D electron liquid present at the LaAlO3_3/SrTiO3_3 interface in series of samples prepared at different growth temperatures. We observe that interfaces fabricated at 650{\deg}C exhibit the highest low temperature mobility (≈10000 cm2/Vs\approx 10000 \textrm{ cm}^2/\textrm{Vs}) and the lowest sheet carrier density (≈5×1012 cm−2\approx 5\times 10^{12} \textrm{ cm}^{-2}). These samples show metallic behavior and Shubnikov-de Haas oscillations in their magnetoresistance. Samples grown at higher temperatures (800-900{\deg}C) display carrier densities in the range of ≈2−5×1013 cm−2\approx 2-5 \times 10^{13} \textrm{ cm}^{-2} and mobilities of ≈1000 cm2/Vs\approx 1000 \textrm{ cm}^2/\textrm{Vs} at 4K. Reducing their carrier density by field effect to 8×1012 cm−28\times 10^{12} \textrm{ cm}^{-2} lowers their mobilites to ≈50 cm2/Vs\approx 50 \textrm{ cm}^2/\textrm{Vs} bringing the conductance to the weak-localization regime

    Tunable Rashba spin-orbit interaction at oxide interfaces

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    The quasi-two-dimensional electron gas found at the LaAlO3/SrTiO3 interface offers exciting new functionalities, such as tunable superconductivity, and has been proposed as a new nanoelectronics fabrication platform. Here we lay out a new example of an electronic property arising from the interfacial breaking of inversion symmetry, namely a large Rashba spin-orbit interaction, whose magnitude can be modulated by the application of an external electric field. By means of magnetotransport experiments we explore the evolution of the spin-orbit coupling across the phase diagram of the system. We uncover a steep rise in Rashba interaction occurring around the doping level where a quantum critical point separates the insulating and superconducting ground states of the system

    MSWI Fly Ash Multiple Washing: Kinetics of Dissolution in Water, as Function of Time, Temperature and Dilution

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    Municipal solid waste incineration fly ash (FA) can represent a sustainable supply of supplementary material to the construction industries if it is pre-treated to remove hazardous substances such as chloride, sulfate, and heavy metals. In this paper, the phenomenology associated with a water washing multi-cycle treatment of FA is investigated, focusing attention upon the mineral dissolution process. The efficacy of the treatment is assessed by leaching tests, according to the European Standard, and discussed in light of the occurring mineral phases. The water-to-solid (L/S) ratio is a crucial parameter, along with the number of washing cycles, for removing halite and sylvite, whereas quartz, calcite, anhydrite, and an amorphous phase remain in the solid residue. The sequential extraction method and dissolution kinetics modelling provide further elements to interpret leaching processes, and suggest that dissolution takes place through a two-step mechanism. Altogether, multi-step washing with L/S = 5 is effective in reducing contaminants under the legal limits for non-hazardous waste disposal, while the legal limits for non-reactive or reusable material cannot be completely reached, owing to sulfate and some heavy metals which still leached out from the residue

    Resurfacing capitate pyrcarbon implant after proximal row carpectomy: A literature review camillo fulchignoni daniele caviglia lorenzo rocchi

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    Up to a decade ago, to treat patients with chronic wrist pain due to advanced stages of arthritis, surgeons had four main solutions: partial or total wrist arthrodesis, total wrist prosthesis and proximal row carpectomy (PRC). Since 2010, a new technique has been described in literature using the Resurfacing Capitate Pyrocarbon Implant (RCPI), combined to PRC. The aim of this article is to review the literatureand determine the indications, outcomes and complications associated with RCPI. An electronic literature research was carried out and pertinent articles were selected. Surgical technique, results and complications described in those articles are presented. From this review of the literature, authors conclude that Resurfacing Capitate Pyrocarbon Implant can be considered as a good alternative to arthrodesis and total wrist arthroplasty, at any ages, when proximal row carpectomy alone would not be indicated

    Two-dimensional quantum oscillations of the conductance at LaAlO3/SrTiO3 interfaces

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    We report on a study of magnetotransport in LaAlO3/SrTiO3 interfaces characterized by mobilities of the order of several thousands cm2^{2}/Vs. We observe Shubnikov-de Haas oscillations that indicate a two-dimensional character of the Fermi surface. The frequency of the oscillations signals a multiple sub-bands occupation in the quantum well or a multiple valley configuration. From the temperature dependence of the oscillation amplitude we extract an effective carrier mass m∗≃1.45m^{*}\simeq1.45\,mem_{e}. An electric field applied in the back-gate geometry increases the mobility, the carrier density and the oscillation frequency.Comment: 4 pages, 4 figure

    P072 The involvement of extracellular Nicotinamide Phosphoribosyltransferase (eNAMPT) and Nicotinate Phosphoribosyltransferase (eNAPRT) in inflammatory bowel disease

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    Abstract Background Nicotinamide phosphoribosyltrasferase (NAMPT) is a pleiotropic enzyme which catalyses the first and rate-limiting step in the biosynthesis of NAD. It is present in two different forms: an intracellular form, called iNAMPT, (Chiarugi et al., 2012), and an extracellular form, eNAMPT. eNAMPT is considered an important factor for granulocyte-colony stimulating factor-(G-CSF)-induced myeloid differentiation, with paracrine and autocrine effects on different cell types (i.e. immune and cancer cells), binding TLR4. NAMPT is structurally and functionally related to the enzyme nicotinate phosphoribosyltransferase (iNAPRT), which is rate-limiting in the NAD salvage pathway that starts from nicotinic acid. The NAD biosynthetic pathways controlled by NAMPT and NAPRT are closely interconnected and can compensate for each other. Also, NAPRT is identified as an extracellular ligand (eNAMPRT) for TLR4 and a mediator of inflammation (Managò et al., 2020). Importantly, iNAMPT and eNAMPT levels are increased in several pathologies, included inflammatory bowel disease (IBD). It has been reported that serum eNAMPT levels correlate with the stage of the pathology: in an active state of the disease the levels of NAMPT are very high, however its levels are partially reduced in a remission stage (Moschen et al., 2007). Methods First, we investigated the role of eNAMPT and eNAPRT in murine IBD models (especially in DNBS and DSS model). We took into account phenotypic effect as weight loss and colon shortening, but also the reduction of mRNA of inflammatory genes with RT-PCR, tissue damage with H&E and IHC analysis and systemic and local production through colon explant. Secondly, we determined serum eNAMPT and eNAPRT levels in a cohort of adult IBD patients. Results Both eNAMPT and eNAPRT have been found elevated in 180 IBD patients, as proinflammatory marker of the pathologies. These levels are also elevated in serum and colonic explant of DSS and DNBS preclinical models, associated to an active state of the disease, as a pro-inflammatory response developed locally and systemically. Moreover, we performed ELISA analysis on sera of 100 IBD patients, eligible for anti-TNF treatment, both pediatric and adults. Serum eNAMPT levels are increased before the treatment, responsive patients verified a reduction of these levels, while no-responsive ones verified higher levels. Conclusion eNAMPT and eNAPRT could be considered pro-inflammatory markers of IBD and possible druggable targets

    Land use intensity and cropping sequence effects on aggregate stability and C storage in a Vertisol and a Mollisol

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    The relevant change in land use due mainly to the rapid expansion of soybean cropping towards areas traditionally occupied for livestock purposes or with native grasslands of South America may have negative consequences on soil organic carbon (SOC) storage and aggregate stability, although the effect may be different between soils with contrasting aggregation agents. The aim of our work was to assess the impact of the land use, measured as the intensification and/or frequency of a given crop, on SOC storage and aggregate stability in two soils differing in their main agents of aggregation. The study was conducted in a Mollisol and a Vertisol of Argentina. Eleven cropped fields (agricultural and crop-pasture rotation) under no-tillage and one uncropped situation (pristine native grassland) were selected in each soil type. The fraction of annual time with plant cover (as a measure of the intensification in the land use) and the frequency of a given crop in the cropping sequence over a 6-year period were calculated. Undisturbed soil samples were collected from each soil at 0-5, 5-15 and 15-30 cm depths. The SOC stocks in equivalent soil mass were calculated using the native grassland as the baseline system. Aggregate stability was evaluated using a method that involved three pretreatments: fast wetting, stirring after prewetting and slow wetting. The intensification improved the aggregate stability in the Mollisol, whereas a low impact of land use on aggregate stability was recorded in the Vertisol. Overall, both the intensification sequence index and the soybean cropping frequency were the best indexes to evaluate the impact of land use on aggregate stability and SOC storage, mainly in the Mollisol. The stirring after prewetting pretreatment was mainly associated with SOC concentration in the Mollisol, appearing as a method with high potential capacity to discriminate land use in the Mollisol, in which the SOC is the main aggregation agent. In contrast, the slow wetting pretreatment was more appropriate to evaluate the impact of land use in the Vertisol. The approach used to evaluate the land use, which included agricultural lands, crop-pasture rotation and native grasslands, evaluated through indexes of occupation with plant cover, was more suitable for the Mollisol than for the Vertisol. This reveals that the evaluation of land use through several indexes should be based on the soil typeFil: Novelli, Leonardo Esteban. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Paraná; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Caviglia, Octavio Pedro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Paraná; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wilson, M. G.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Paraná; Argentina. Universidad Nacional de Entre Ríos. Facultad de Ciencias Agropecuarias; ArgentinaFil: Casal, M. C.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Entre Ríos. Estación Experimental Agropecuaria Paraná; Argentin

    The Impact of Dysmetabolic Sarcopenia Among Insulin Sensitive Tissues: A Narrative Review

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    Sarcopenia is a common muscular affection among elderly individuals. More recently, it has been recognized as the skeletal muscle (SM) expression of the metabolic syndrome. The prevalence of sarcopenia is increasing along with visceral obesity, to which it is tightly associated. Nonetheless, it is a still underreported entity by clinicians, despite the worsening in disease burden and reduced patient quality of life. Recognition of sarcopenia is clinically challenging, and variability in study populations and diagnostic methods across the clinical studies makes it hard to reach a strong evidence. Impaired insulin activity in SM is responsible for the altered molecular pathways and clinical manifestations of sarcopenia, which is morphologically expressed by myosteatosis. Lipotoxicity, oxidative stress and adipose tissue-derived inflammation lead to both alterations in glucose disposal and protein synthesis in SM, with raising insulin resistance (IR) and SM atrophy. In particular, hyperleptinemia and leptin resistance interfere directly with SM activity, but also with the release of Growth Hormone from the hypohysis, leading to a lack in its anabolic effect on SM. Moreover, sarcopenia is independently associated to liver fibrosis in Non-Alcoholic Fatty Liver Disease (NAFLD), which in turn worsens SM functionality through the secretion of proinflammatory heptokines. The cross-talk between the liver and SM in the IR setting is of crucial relevance, given the high prevalence of NAFLD and the reciprocal impact of insulin-sensitive tissues on the overall disease burden. Along with the efforts of non-invasive diagnostic approaches, irisin and myostatin are two myokines currently evaluated as potential biomarkers for diagnosis and prognostication. Decreased irisin levels seem to be potentially associated to sarcopenia, whereas increased myostatin has shown to negatively impact on sarcopenia in pre-clinical studies. Gene variants in irisin have been explored with regard to the impact on the liver disease phenotype, with conflicting results. The gut-muscle axis has gain relevance with the evidence that insulin resistance-derived gut dysbiosis is responsible for increased endotoxemia and reduction in short-chain free fatty acids, directly affecting and predisposing to sarcopenia. Based on the current evidence, more efforts are needed to increase awareness and improve the management of sarcopenic patients
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