80 research outputs found

    Dynamic Fire Danger Mapping from Satellite Imagery and Meteorological Forecast Data

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    Abstract This study aims at ascertaining if and how remote sensing data can improve fire danger estimation based on meteorological variables. With this goal in mind, a dynamic estimation of fire danger was performed using an approach based on the integration of satellite information within a comprehensive fire danger rating system. The performances obtained with and without using satellite data were carried out for fires that occurred during the fire season in the year 2003 in the Calabria region (southern Italy). This study area was selected, first, because it is highly representative of Mediterranean ecosystems and, second, because it is an interesting test case for wildfire occurrences within the Mediterranean basin. The results obtained have shown that the use of satellite data reduced efficiently the overestimated danger areas, thus improving at least by 10% the fire forecasting rate obtained without using satellite-based maps. Such findings can be directly extended to other similar Mediterranean ecosystems

    An original FE modelling of a longitudinal multi-passes seam welding

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    Abstract Both finite element and analytical methods for simulation of welding are essential to predict residual stress and distortions of welded components. Best FE modelling is obtained by using solid elements for thermo-structural simulation with high computational cost. In this contest, an equivalent modelling of plates based on shell elements is proposed in order to streamline the simulations. The equivalent model is composed of n levels of shell elements, centered on the weld seam, in order to evaluate rotations and translations typical of a multi-pass weld. There are as many levels as the number of the weld passes that compose the seam. The interconnection between the n shell levels is realized by rigid beam elements. The latter ones are connected to shell elements by constraint equations. Solid brick models of the plates are used as a benchmark for the equivalent models in thermal and mechanical simulations. The equivalent modelling is in good agreement with solid results, showing a strong decrease of computational burden, enabling the simulation of large welded models in operative conditions

    Alterations of clock gene RNA expression in brain Regions of a triple transgenic model of Alzheimer's Disease

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    A disruption to circadian rhythmicity and the sleep/wake cycle constitutes a major feature of Alzheimer's disease (AD). The maintenance of circadian rhythmicity is regulated by endogenous clock genes and a number of external Zeitgebers, including light. This study investigated the light induced changes in the expression of clock genes in a triple transgenic model of AD (3×Tg-AD) and their wild type littermates (Non-Tg). Changes in gene expression were evaluated in four brain areas¾suprachiasmatic nucleus (SCN), hippocampus, frontal cortex and brainstem¾of 6- and 18-month-old Non-Tg and 3×Tg-AD mice after 12 h exposure to light or darkness. Light exposure exerted significant effects on clock gene expression in the SCN, the site of the major circadian pacemaker. These patterns of expression were disrupted in 3×Tg-AD and in 18-month-old compared with 6-month-old Non-Tg mice. In other brain areas, age rather than genotype affected gene expression; the effect of genotype was observed on hippocampal Sirt1 expression, while it modified the expression of genes regulating the negative feedback loop as well as Rorα, Csnk1ɛ and Sirt1 in the brainstem. In conclusion, during the early development of AD, there is a disruption to the normal expression of genes regulating circadian function after exposure to light, particularly in the SCN but also in extra-hypothalamic brain areas supporting circadian regulation, suggesting a severe impairment of functioning of the clock gene pathway. Even though this study did not demonstrate a direct association between these alterations in clock gene expression among brain areas with the cognitive impairments and chrono-disruption that characterize the early onset of AD, our novel results encourage further investigation aimed at testing this hypothesis

    Serum and supplement optimization for EU GMP-compliance in cardiospheres cell culture

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    Cardiac progenitor cells (CPCs) isolated as cardiospheres (CSs) and CS-derived cells (CDCs) are a promising tool for cardiac cell therapy in heart failure patients, having CDCs already been used in a phase I/II clinical trial. Culture standardization according to Good Manufacturing Practices (GMPs) is a mandatory step for clinical translation. One of the main issues raised is the use of xenogenic additives (e.g. FBS, foetal bovine serum) in cell culture media, which carries the risk of contamination with infectious viral/prion agents, and the possible induction of immunizing effects in the final recipient. In this study, B27 supplement and sera requirements to comply with European GMPs were investigated in CSs and CDCs cultures, in terms of process yield/efficiency and final cell product gene expression levels, as well as phenotype. B27- free CS cultures produced a significantly reduced yield and a 10-fold drop in c-kit expression levels versus B27+ media. Moreover, autologous human serum (aHS) and two different commercially available GMP AB HSs were compared with standard research-grade FBS. CPCs from all HSs explants had reduced growth rate, assumed a senescent-like morphology with time in culture, and/or displayed a significant shift towards the endothelial phenotype. Among three different GMP gamma-irradiated FBSs (giFBSs) tested, two provided unsatisfactory cell yields, while one performed optimally, in terms of CPCs yield/phenotype. In conclusion, the use of HSs for the isolation and expansion of CSs/CDCs has to be excluded because of altered proliferation and/or commitment, while media supplemented with B27 and the selected giFBS allows successful EU GMP-complying CPCs culture

    An aqueous olive leaf extract (OLE) ameliorates parameters of oxidative stress associated with lipid accumulation and induces lipophagy in human hepatic cells

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    Fatty liver is a disease characterized by a buildup of lipids in the liver, often resulting from excessive consumption of high-fat-containing foods. Fatty liver can degenerate, over time, into more severe forms of liver diseases, especially when oxidative stress occurs. Olive leaf extract (OLE) is a reliable source of polyphenols with antioxidant and hypolipidemic properties that have been successfully used in medicine, cosmetics, and pharmaceutical products. Using "green" solvents with minimal impact on the environment and human health, which simultaneously preserves the extract's beneficial properties, represents one of the major challenges of biomedical research. In the present study, we assayed the potential antioxidant and lipid-lowering effect of a "green" OLE obtained by a water ultrasound-assisted extraction procedure, on the human hepatic HuH7 cell line, treated with a high concentration of free fatty acids (FFA). We found that high FFA concentration induced lipid accumulation and oxidative stress, as measured by increased hydrogen peroxide levels. Moreover, the activity of antioxidant enzymes, catalase, superoxide dismutase, and glutathione peroxidase, was reduced upon FFA treatment. Coincubation of high FFA with OLE reduced lipid and H2O2 accumulation and increased the activity of peroxide-detoxifying enzymes. OLE ameliorated mitochondrial membrane potential, and hepatic parameters by restoring the expression of enzymes involved in insulin signaling and lipid metabolism. Electron microscopy revealed an increased autophagosome formation in both FFA- and FFA + OLE-treated cells. The study of the autophagic pathway indicated OLE's probable role in activating lipophagy

    Nutrition and IBD: Malnutrition and/or Sarcopenia? A Practical Guide

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    Malnutrition is a major complication of inflammatory bowel disease (IBD). This mini review is focusing on main determinants of malnutrition in IBD, the most important components of malnutrition, including lean mass loss and sarcopenia, as an emerging problem. Each one of these components needs to be well considered in a correct nutritional evaluation of an IBD patient in order to build a correct multidisciplinary approach. The review is then focusing on possible instrumental and clinical armamentarium for the nutritional evaluation
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