2,427 research outputs found

    Autohydrolysis followed by ionic liquid treatment for Eucalyptus globulus wood fractionation

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    The 2030 Agenda for Sustainable Development recognises the need for a green and sustainable chemistry and engineering [1]. In this context, cleaner processes require the substitution of organic solvents by less harmful solvents. In addition, the solvent selection for a biomass processing is crucial for the environmental sustainability and feasibility of a biorefinery [2]. In this work, water and the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) were chosen as green solvents for a selective fractionation of Eucalyptus globulus wood in order to valorise their main fractions (hemicellulose, cellulose and lignin). Two sequential stages were proposed for the biomass processing. First, an autohydrolysis step allowed the hemicellulose solubilisation and its recovery as oligosaccharides in the aqueous liquid phase, yielding a solid phase composed by 60 % glucan and 34 % lignin. Second, a treatment with [C2mim][OAc] was evaluated for the delignification of the autohydrolysed biomass. Optimisation of operational conditions (temperature and time) of the ionic liquid treatment was performed to improve the enzymatic saccharification of cellulose remaining in the solid phase and to solubilise lignin. The proposed process configuration is expected to contribute towards the development of integrated biorefineries based on hardwood biomass.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit, BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional doNorte, the EcoTech project (POCI01-0145-FEDER-032206). Aloia Romaní thanks the Iacobus Program (European Territorial Cooperation Partnership Galicia – Norte de Portugal) for a mobility fellowship.info:eu-repo/semantics/publishedVersio

    An Instanton Picture O.P.E. <A^2> Condensate?

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    Gluon two- and three-point Green Functions computed in Landau gauge from the lattice show the existence of power corrections to the purely perturbative expressions, that can be explained through an Operator Product Expansion as the influence of a non gauge invariant mass dimension two condensate. The relationship of this condensate with topological properties of QCD, namely instantons, will be studied, giving a first estimate of the contribution of instantons to this condensate based in the direct lattice measure, after a cooling process, of the instanton liquid properties.Comment: Lattice2002(topology) contribution, 3 pages, 2 figure

    O.P.E. and Power Corrections to the QCD coupling constant

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    Lattice data seems to show that power corrections should be convoked to describe appropriately the transition of the QCD coupling constant running from U.V. to I.R. domains. Those power corrections for the Landau-gauge MOM coupling constant in a pure Yang-Mills theory (N_f=0) are analysed in terms of Operator Product Expansion (O.P.E.) of two- and three-point Green functions, the gluon condensate emerging from this study. The semi-classical picture given by instantons can be also used to look for into the nature of the power corrections and gluon condensate.Comment: 5 pages, talk given at XXX International Meeting on Fundamental Physics, Jaca 200

    Graphene Synthesis Using a CVD Reactor and a Discontinuous Feed of Gas Precursor at Atmospheric Pressure

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    The present work shows a new method in order to cost-effectively achieve the synthesis of graphene by Chemical Vapor Deposition (CVD). Unlike most usual processes, where precursors such as argon, H2, CH4, and high purity copper foil are used, the proposed method has replaced the previous ones by N2, N2 (90%) : H2 (10%), C2H2, and electrolytic copper (technical grade) since the use of industrialized precursors helps reduce production costs. On the other hand, the process was modified from a continuous flow system with vacuum to a discontinuous one at atmospheric pressure, eliminating the use of vacuum pump. In addition, this modification optimized the consumption of gases, which reduced the waste and the emission of pollutant gases into the atmosphere. Graphene films were grown under different gas flowrates and temperatures. Then, the obtained material was characterized by TEM, Raman spectroscopy, and AFM, confirming the presence of few graphene layers. In brief, the growth time was reduced to six minutes with acetylene as a carbon precursor at 1000°C and at atmospheric pressure, with a flow rate of 30 sccm. Finally, the reported conditions can be used for the synthesis of good quality graphene films in industrial applications

    p120 catenin induces opposing effects on tumor cell growth depending on E-cadherin expression

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    p120 catenin regulates the activity of the Rho family guanosine triphosphatases (including RhoA and Rac1) in an adhesion-dependent manner. Through this action, p120 promotes a sessile cellular phenotype when associated with epithelial cadherin (E-cadherin) or a motile phenotype when associated with mesenchymal cadherins. In this study, we show that p120 also exerts significant and diametrically opposing effects on tumor cell growth depending on E-cadherin expression. Endogenous p120 acts to stabilize E-cadherin complexes and to actively promote the tumor-suppressive function of E-cadherin, potently inhibiting Ras activation. Upon E-cadherin loss during tumor progression, the negative regulation of Ras is relieved; under these conditions, endogenous p120 promotes transformed cell growth both in vitro and in vivo by activating a Rac1–mitogen-activated protein kinase signaling pathway normally activated by the adhesion of cells to the extracellular matrix. These data indicate that both E-cadherin and p120 are important regulators of tumor cell growth and imply roles for both proteins in chemoresistance and targeted therapeutics

    Instantons and <A2><A^2> Condensate

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    We argue that the condensatefoundintheLandaugaugeonlattices,whenanOperatorProductExpansionofGreenfunctionsisperformed,mightbeexplainedbyinstantons.Weusecoolingtoestimatetheinstantoncontributionandextrapolatebacktheresulttothethermalisedconfiguration.Theresulting condensate found in the Landau gauge on lattices, when an Operator Product Expansion of Green functions is performed, might be explained by instantons. We use cooling to estimate the instanton contribution and extrapolate back the result to the thermalised configuration. The resulting is similar to .Comment: 6 pages, 1 fig., 1 tab., RevTeX to be use

    Sperm Hyperactivation and Capacitation Induced By Light Stimuli in Cryopreserved Semen

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    In mammals, such as rabbits, there are some factors involved in possible fertilization, from complex changes in the membrane of the sperm to obstruction or non-existent of vas deferens, which creates problems in the number and quality of sperm. In this work, we report the effects of rabbit sperm motility and capacitation of cryopreserved semen samples under light stimuli. The sperm velocities were correlated with the percentage of capacitated and non-capacitated sperm seen with a fluorescent dye. Consequently, we analyzed the specific correlations between irradiation times, supplied energy, and fertility parameters. KEYWORDS THAT SEARCHED RELATED TO THE ARTICLE ON THE WEB sperm meaning, capacitation, human sperm, capacitation occurs in, what is sperm, capacitation of sperm, sperm lifetime, fertilization definition, fertilization meaning, capacitation meaning, mechanism of fertilization,sperm capacitation, capacitate meaning, fertilization takes place in, capacitate, capacitation of sperm occurs in, capacitation of sperms, capacitated, definition of fertilizatio

    Immune-mediated hookworm clearance and survival of a marine mammal decrease with warmer ocean temperatures

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    Indexación: Scopus.We appreciate the logistical support of the Chilean Navy, Artisanal fishermen of Quellon (Vessel crews Marimar II and Nautylus V), and the crews of the Chilean Navy lighthouse. We thank Amanda Hooper, Eugene DeRango, Elvira Vergara, Ignacio Silva, Dr. Lorraine Barbosa, Emma Milner, Sian Tarrant, Emily Morris, Suzette Miller, and Piero Becker for dedicated field assistance. We thank Dr. Vanesa Ezenwa for comments and insights in earlier versions of the manuscript. This work was supported by The Rufford Small Grant Foundation (Grant N 18815–1), Morris Animal Foundation (Grant N D16ZO-413), and the Society for Marine Mammalogy Small Grants in aid awards 2015 and 2016.Increases in ocean temperature are associated with changes in the distribution of fish stocks, and the foraging regimes and maternal attendance patterns of marine mammals. However, it is not well understood how these changes affect offspring health and survival. The maternal attendance patterns and immunity of South American fur seals were assessed in a rookery where hookworm disease is the main cause of pup mortality. Pups receiving higher levels of maternal attendance had a positive energy balance and a more reactive immune system. These pups were able to expel hookworms through a specific immune mediated mechanism and survived the infection. Maternal attendance was higher in years with low sea surface temperature, therefore, the mean hookworm burden and mortality increased with sea surface temperature over a 10-year period. We provide a mechanistic explanation regarding how changes in ocean temperature and maternal care affect infectious diseases dynamics in a marine mammal. © Seguel et al.https://elifesciences.org/articles/3843
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