1,052 research outputs found

    The role of the commensal microbiota in the regulation of tolerance to dietary allergens.

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    In this report we review the evidence that environmental stimuli that perturb naturally selected host-microbe interactions are driving the increasing prevalence of food allergy and examine the mechanisms by which commensal bacteria regulate tolerance to dietary allergens. Recent findings Antibiotic use and the consumption of a high fat/low fiber diet have a major, and rapid, impact on gut bacterial populations with long-term consequences for both overall microbial community structure and the regulation of host immunity. Recent work emphasizes the role of mucosa-associated commensal bacteria in eliciting a barrier protective response critical to preventing allergic sensitization to food. Murine model studies are informing the development of novel live biotherapeutic approaches as an adjunctive therapy to enhance antigen specific oral desensitization and promote lasting tolerance in patients with food allergy. Summary Strategies based on modulating the composition and/or functionality of the gut microbiome hold promise for the treatment of food allergy

    Síntese de nanopartículas de prata para aplicação na sanitização de embalagens.

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    bitstream/CNPDIA-2009-09/11896/1/CT99_2008.pd

    Altura e suprimento de nitrogênio afetando a Plutella xylostella na couve-de-folhas sob cobertura plástica.

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    O objetivo desse trabalho foi estudar a influência da altura e do forneciento de N sobre o ataque dessa traça em plantas de couve (cv. hi-crop) cultivadas em vasos, dentro de cultivo dessa brassicácea sob cobertura plástica.Edição dos Resumos do 52º Congresso Brasileiro de Olericultura, Salvador, jul. 2012

    Experimental Investigation of the Evolution of Gaussian Quantum Discord in an Open System

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    Gaussian quantum discord is a measure of quantum correlations in Gaussian systems. Using Gaussian discord we quantify the quantum correlations of a bipartite entangled state and a separable two-mode mixture of coherent states. We experimentally analyze the effect of noise addition and dissipation on Gaussian discord and show that the former noise degrades the discord while the latter noise for some states leads to an increase of the discord. In particular, we experimentally demonstrate the near-death of discord by noisy evolution and its revival through dissipation.Comment: 5 pages, 5 figure

    Vegetation height products between 60° S and 60° N from ICESat GLAS data.

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    We present new coarse resolution (0.5� ×0.5�)vegetation height and vegetation-cover fraction data sets between 60� S and 60� N for use in climate models and ecological models. The data sets are derived from 2003–2009 measurements collected by the Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud and land Elevation Satellite (ICESat), the only LiDAR instrument that provides close to global coverage. Initial vegetation height is calculated from GLAS data using a development of the model of Rosette et al. (2008) with further calibration on desert sites. Filters are developed to identify and eliminate spurious observations in the GLAS data, e.g. data that are affected by clouds, atmosphere and terrain and as such result in erroneous estimates of vegetation height or vegetation cover. Filtered GLAS vegetation height estimates are aggregated in histograms from 0 to 70m in 0.5m intervals for each 0.5�×0.5�. The GLAS vegetation height product is evaluated in four ways. Firstly, the Vegetation height data and data filters are evaluated using aircraft LiDAR measurements of the same for ten sites in the Americas, Europe, and Australia. Application of filters to the GLAS vegetation height estimates increases the correlation with aircraft data from r =0.33 to r =0.78, decreases the root-mean-square error by a factor 3 to about 6m (RMSE) or 4.5m (68% error distribution) and decreases the bias from 5.7m to −1.3 m. Secondly, the global aggregated GLAS vegetation height product is tested for sensitivity towards the choice of data quality filters; areas with frequent cloud cover and areas with steep terrain are the most sensitive to the choice of thresholds for the filters. The changes in height estimates by applying different filters are, for the main part, smaller than the overall uncertainty of 4.5–6m established from the site measurements. Thirdly, the GLAS global vegetation height product is compared with a global vegetation height product typically used in a climate model, a recent global tree height product, and a vegetation greenness product and is shown to produce realistic estimates of vegetation height. Finally, the GLAS bare soil cover fraction is compared globally with the MODIS bare soil fraction (r = 0.65) and with bare soil cover fraction estimates derived from AVHRR NDVI data (r =0.67); the GLAS treecover fraction is compared with the MODIS tree-cover fraction (r =0.79). The evaluation indicates that filters applied to the GLAS data are conservative and eliminate a large proportion of spurious data, while only in a minority of cases at the cost of removing reliable data as well. The new GLAS vegetation height product appears more realistic than previous data sets used in climate models and ecological models and hence should significantly improve simulations that involve the land surface

    Direct effects of fermented cow's milk product with Lactobacillus paracasei CBA L74 on human enterocytes

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    Cow's milk fermented with Lactobacillus paracasei CBA L74 (FM-CBAL74) exerts a preventive effect against infectious diseases in children. We evaluated if this effect is at least in part related to a direct modulation of non-immune and immune defence mechanisms in human enterocytes. Human enterocytes (Caco-2) were stimulated for 48 h with FM-CBAL74 at different concentrations. Cell growth was assessed by colorimetric assay; cell differentiation (assessed by lactase expression), tight junction proteins (zonula occludens1 and occludin), mucin 2, and toll-like receptor (TRL) pathways were analysed by real-time PCR; innate immunity peptide synthesis, beta-defensin-2 (HBD-2) and cathelicidin (LL-37) were evaluated by ELISA. Mucus layer thickness was analysed by histochemistry. FMCBA L74 stimulated cell growth and differentiation, tight junction proteins and mucin 2 expression, and mucus layer thickness in a dose-dependent fashion. A significant stimulation of HBD-2 and LL-37 synthesis, associated with a modulation of TLR pathway, was also observed. FM-CBAL74 regulates non-immune and immune defence mechanisms through a direct interaction with the enterocytes. These effects could be involved in the preventive action against infectious diseases demonstrated by this fermented product in children

    A Preliminary 1D-3D Analysis of the Darmstadt Research Engine under Motored Condition

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    In the present paper, 1D and 3D CFD models of the Darmstadt research engine undergo a preliminary validation against the available experimental dataset at motored condition. The Darmstadt engine is a single-cylinder optical research unit and the chosen operating point is characterized by a revving speed equal to 800 rpm with intake temperature and pressure of 24 \ub0C and 0.95 bar, respectively. Experimental data are available from the TU Darmstadt engine research group. Several aspects of the engine are analyzed, such as crevice modeling, blow-by, heat transfer and compression ratio, with the aim to minimize numerical uncertainties. On the one hand, a GT-Power model of the engine is used to investigate the impact of blow-by and crevices modeling during compression and expansion strokes. Moreover, it provides boundary conditions for the following 3D CFD simulations. On the other hand, the latter, carried out in a RANS framework with both highand low-Reynolds wall treatments, allow a deeper investigation of the boundary layer phenomena and, thus, of the gas-to-wall heat transfer. A detailed modeling of the crevice, along with an ad hoc tuning of both blow-by and heat fluxes lead to a remarkable improvement of the results. However, in order to adequately match the experimental mean in-cylinder pressure, a slight modification of the compression ratio from the nominal value is accounted for, based on the uncertainty which usually characterizes such geometrical parameter. The present preliminary study aims at providing reliable numerical setups for 1D and 3D models to be adopted in future detailed investigations on the Darmstadt research engine

    Controle da brusone nas folhas de arroz de terras altas em resposta ao tratamento de sementes e época de plantio.

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    O presente trabalho objetivou estudar a influência da época de plantio e tratamento de sementes em duas cultivares melhoradas de arroz de terras altas e uma linhagem promissora.bitstream/CNPAF/18764/1/pqfoco55.pd
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