135 research outputs found

    Pseudomonas aeruginosa and Its 4 Arsenal of Proteases: Weapons 5 to Battle the Host

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    Pseudomonas aeruginosa is a ubiquitous and opportunistic human pathogen that 12 represents a critical problem to the clinician due to the increased number of 13 resistant strains isolated from hospital settings. In addition, there is a great 14 variety of pathologies associated with this versatile Gram-negative bacterium. 15 P. aeruginosa cells are able to produce an incredible arsenal of virulence factors, 16 especially secreted molecules that act singly or together to ensure the 17 establishment, maintenance, and persistence of a successful infection in 18 susceptible hosts. In this context, pseudomonal proteases roles are highlighted 19 due to their ability to cleave key host proteinaceous substrates as well as to 20 modulate several biological processes, for example, escaping and modulating the 21 host immune responses in the bacterial own favor. Proteases secreted by 22 P. aeruginosa include elastase A (LasA), elastase B (LasB), alkaline protease 23 (AP), protease IV (PIV), Pseudomonas small protease (PASP), large protease A 24 (LepA), MucD, and P. aeruginosa aminopeptidase (PAAP). In the present 25 review, we discuss the role of each of these relevant proteases produced by P. aeruginosa taking into consideration their main biological functions in the 27 bacterium–host interaction that favors the establishment of the infectious 28 proces

    Abrupt weaning type combined to stress during late pregnancy in sheep present economic losses on carcass and low testicular development in lambs

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    This study investigates the combined effect of the progressive or abrupt weaning after the stress during middle and late pregnancy on performance and development of lambs. Twenty-four male lambs were used, born from 18 Santa Ines ewes that were divided into three experimental groups. Pregnant ewes were submitted to the application of Lipolysaccharides E. coli (LPS) during the 70 th day of pregnancy (Ig; n=12) or at the 120 th day (Fg; n=8). Animals were kept as control (Cg; n=14). Lambs born in a 6 day interval were subjected to two types of weaning (Pw: progressive weaning; Aw: abrupt weaning at 45 days of age). Lamb data, including testicular development, yield carcass and economic cost were analyzed. Means were compared by F test and Student's t test (P0.05). The highest yields in gross margin was observed for the Cg group and the lowest for Fg (P0.05). On lambs’ testicular weight, Cg average value was higher than Fg (P0.05). The combined effect of LPS challenge as a simulated disease process during late pregnancy and abrupt weaning change the testicular weight and the yield carcass, resulting in economic losses

    Correction of Basic Equations for Deep Bed Filtration with Dispersion

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    Copyright © 2006 Elsevier B.V. All rights reserved.Deep bed filtration of particle suspensions in porous media occurs during water injection into oil reservoirs, drilling fluid invasion into reservoir productive zones, fines migration in oil fields, bacteria, virus or contaminant transport in groundwater, industrial filtering, etc. The basic features of the process are advective and dispersive particle transport and particle capture by the porous medium. Particle transport in porous media is determined by advective flow of carrier water and by hydrodynamic dispersion in micro-heterogeneous media. Thus, the particle flux is the sum of advective and dispersive fluxes. Transport of particles in porous media is described by an advection–diffusion equation and by a kinetic equation of particle capture. Conventional models for deep bed filtration take into account hydrodynamic particle dispersion in the mass balance equation but do not consider the effect of dispersive flux on retention kinetics. In the present study, a model for deep bed filtration with particle size exclusion taking into account particle hydrodynamic dispersion in both mass balance and retention kinetics equations is proposed. Analytical solutions are obtained for flows in infinite and semi-infinite reservoirs and in finite porous columns. The physical interpretation of the steady-state flow regimes described by the proposed and the traditional models favours the former.Altoe, J. E., Bedrikovetski, P.G., Siqueira, A. G., de Souza, A. L., Shecaira, F.http://www.elsevier.com/wps/find/journaldescription.cws_home/503345/description#descriptio

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

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    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
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