841 research outputs found

    Fischer-Tropsch synthesis in microchannels

    Get PDF
    Different metallic supports (aluminum foams of 40ppi, honeycomb monolith and micromonolith of 350 and 1180cpsi, respectively) have been loaded with a 20%Co-0.5%Re/γ-Al2O3 catalyst by the washcoating method. Layers of different thicknesses have been deposited onto the metallic supports. The catalytic coatings were characterized measuring their textural properties, adhesion and morphology. These structured catalysts have been tested in the Fischer-Tropsch synthesis (FTS) and compared with a microchannel block presenting perpendicular channels for reaction and cooling. The selectivity depends on the type of support used and mainly on the thickness of the layer deposited. In general, the C5+ selectivity decreased at increasing CO conversion for all of the systems (powder, monoliths, foams and microchannels block). On the other hand, the selectivity to methane increased with the thickness of the catalytic layer due to the higher effective H2/CO ratio over the active sites resulting from the higher diffusivity of H2 compared with CO in the liquid products filling the pores. The C5+ selectivity of the microchannels reactor is higher than that of the structured supports and the powder catalyst.Ministerio de Ciencia e Innovación MAT2006-12386-C05, ENE2009-14522-C0

    Estado Da Arte Da Literatura Científica Sobre Hancornia Speciosa: Tendências E Lacunas

    Get PDF
    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The economic and scientific interest in Hancornia speciosa (mangabeira) has been growing in recent years, mainly due to the marketing of fruit and extraction of natural compounds with high pharmacological potential. In this study, a scientometric survey about mangabeira was carried out in order to promote and direct future studies on the species. As a result, low scientific productivity associated with this species was found, with only 131 articles published in the last 69 years. In addition, this study identified some trends in bibliographic production on mangabeira, among them: the increasing number of articles over the years; scientific dissemination in nationwide journals; the main focus of this study is associated with agronomic studies; the experimental approach is more frequent and usually associated with populations of restricted geographical distribution; and the scientific production is mainly from education institutions. Furthermore, this study also allowed the identification of some gaps in knowledge about mangabeira, among them the difficulty in describing and characterizing botanical lines; lack of analysis of the genetic diversity of widely distributed populations; lack of management and conservation projects for the species; lack of description of cultivation, collection and preservation techniques of fruits; and lack of identification of natural compounds responsible for its pharmacological activity. It is expected that the data generated in this study will serve to direct future studies on H. speciosa. © 2016, Sociedade Brasileira de Fruticultura. All rights reserved.384CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorCNPq, Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPEG, Fundação de Amparo à Pesquisa do Estado de GoiásFINEP, Financiadora de Estudos e ProjetosCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Activity of daptomycin- and vancomycin-loaded poly-epsilon-caprolactone microparticles against mature staphylococcal biofilms.

    Get PDF
    The aim of the present study was to develop novel daptomycin-loaded poly-epsilon-caprolactone (PCL) microparticles with enhanced antibiofilm activity against mature biofilms of clinically relevant bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and polysaccharide intercellular adhesin-positive Staphylococcus epidermidis. Daptomycin was encapsulated into PCL microparticles by a double emulsion-solvent evaporation method. For comparison purposes, formulations containing vancomycin were also prepared. Particle morphology, size distribution, encapsulation efficiency, surface charge, thermal behavior, and in vitro release were assessed. All formulations exhibited a spherical morphology, micrometer size, and negative surface charge. From a very early time stage, the released concentrations of daptomycin and vancomycin were higher than the minimal inhibitory concentration and continued so up to 72 hours. Daptomycin presented a sustained release profile with increasing concentrations of the drug being released up to 72 hours, whereas the release of vancomycin stabilized at 24 hours. The antibacterial activity of the microparticles was assessed by isothermal microcalorimetry against planktonic and sessile MRSA and S. epidermidis. Regarding planktonic bacteria, daptomycin-loaded PCL microparticles presented the highest antibacterial activity against both strains. Isothermal microcalorimetry also revealed that lower concentrations of daptomycin-loaded microparticles were required to completely inhibit the recovery of mature MRSA and S. epidermidis biofilms. Further characterization of the effect of daptomycin-loaded PCL microparticles on mature biofilms was performed by fluorescence in situ hybridization. Fluorescence in situ hybridization showed an important reduction in MRSA biofilm, whereas S. epidermidis biofilms, although inhibited, were not eradicated. In addition, an important attachment of the microparticles to MRSA and S. epidermidis biofilms was observed. Finally, all formulations proved to be biocompatible with both ISO compliant L929 fibroblasts and human MG63 osteoblast-like cells

    QUANTIFICAÇÃO HISTOLÓGICA DA ESPERMATOGÊNESE DE RATOS WISTAR TRATADOS COM DIMETIL SULFÓXIDO

    Get PDF
    Avaliaram-se através de histologia testicular quantitativa os efeitos da ação do Dimetil Sulfóxido (DMSO) na espermatogênese de 28 ratos adultos albinos da raça Wistar. Os animais foram divididos em dois grupos - Controle e Experimental - e submetidos a dois tipos de tratamento: no primeiro tratamento, o Grupo Experimental (10 animais) recebeu aplicações tópicas de DMSO no jarrete, duas vezes ao dia, na dosagem de 1 g/kg-1 de peso vivo, durante sete dias consecutivos; no segundo tratamento, o Grupo Experimental (7 animais) recebeu aplicações tópicas de DMSO no escroto duas vezes ao dia, na dosagem de 1 g/kg-1 de peso vivo, durante 54 dias consecutivos; os Grupos Controles (8 e 3 animais) receberam aplicações de solução salina friccionada na pele do jarrete e do escroto duas vezes ao dia, por período equivalente ao dos tratamentos, respectivamente. Proporções volumétricas dos componentes do parênquima testicular, diâmetro dos túbulos seminíferos, contagem dos elementos celulares do epitélio seminífero e rendimento intrínseca da espermatogênese não apresentaram diferença significativa entre os grupos Controles e Experimentais. O processo espermatogênico não sofreu alteração após a aplicação do DMSO. Histological quantification of spermatogenesis in dimethyl sulfoxide treated wistar rats Abstract In order to provide a more accurate analysis on the effects of dimethyl sulfoxide (DMSO) on spermatogenesis in mammals, an experiment was carried out with albino Wistar rats. A total of 28 rats, 78 days old and average weight of 325 g were divided in one control group and two experimental groups - G1 and G2. Rats from G1 were treated with topic applications of DMSO in the hock twice a day at a dosage of 1.0 g/kg of live weight for 7 consecutive days. Rats from G2 received topic applications of DMSO at the scrotum twice a day at a dosage of 1.0 g/kg of live weight for 54 consecutive days. The control group was swabbed with saline on the hock and the scrotal skin twice a day for the same period as the treatment of G1 and G2 groups. Volumetric proportions of the testicular parenchyma, diameter of the somniferous tubules, counting of cell types in the somniferous epithelium and intrinsic spermatogenesis yield showed no significant differences (

    Solar Intranetwork Magnetic Elements: bipolar flux appearance

    Full text link
    The current study aims to quantify characteristic features of bipolar flux appearance of solar intranetwork (IN) magnetic elements. To attack such a problem, we use the Narrow-band Filter Imager (NFI) magnetograms from the Solar Optical Telescope (SOT) on board \emph{Hinode}; these data are from quiet and an enhanced network areas. Cluster emergence of mixed polarities and IN ephemeral regions (ERs) are the most conspicuous forms of bipolar flux appearance within the network. Each of the clusters is characterized by a few well-developed ERs that are partially or fully co-aligned in magnetic axis orientation. On average, the sampled IN ERs have total maximum unsigned flux of several 10^{17} Mx, separation of 3-4 arcsec, and a lifetime of 10-15 minutes. The smallest IN ERs have a maximum unsigned flux of several 10^{16} Mx, separations less than 1 arcsec, and lifetimes as short as 5 minutes. Most IN ERs exhibit a rotation of their magnetic axis of more than 10 degrees during flux emergence. Peculiar flux appearance, e.g., bipole shrinkage followed by growth or the reverse, is not unusual. A few examples show repeated shrinkage-growth or growth-shrinkage, like magnetic floats in the dynamic photosphere. The observed bipolar behavior seems to carry rich information on magneto-convection in the sub-photospheric layer.Comment: 26 pages, 14 figure

    II Ciclo de Conferências : Conselho Técnico-Científico: temas atuais em investigação

    Get PDF
    A obra é constituída pelos resumos das comunicações apresentadas pelos docentes da Escola Superior Agrária do Instituto Politécnico de Castelo Branco e são referentes aos projetos de investigação nos quais estão envolvidos.O atual Conselho Técnico-Científico (CTC) da Escola Superior Agrária de Castelo Branco (ESACB) tomou posse em fevereiro de 2012, tendo decidido dar continuidade ao ciclo de conferências iniciado pelo CTC anterior. Os trabalhos de Investigação, Inovação e Experimentação que foram apresentados demonstram não só o dinamismo e a ligação com a comunidade, como também a preocupação na identificação e resolução de problemas, que acrescentem valor aos produtos e processos que se situam no âmbito das competências desta Escola. Sendo este um objetivo prioritário da missão do IPCB/ESA, a divulgação destas conferências permite chegar a um público mais alargado e abrir caminhos para a concretização de novos projetos, que contribuam de forma efetiva para o desenvolvimento e aumento da competitividade da região e do país
    corecore