810 research outputs found

    Celebratory Symposium C – Carbon: an Essential Element Carbon as a Natural Element, Chemistry and Life

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    Galileo Comes to the Surface!

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    Galileo Comes to the Surface!

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    Operação sequencial de um sistema batch para biosorção e mineralização anaeróbia de efluentes de lacticínios

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    Um efluente lácteo real enriquecido em gordura foi mineralizado a metano num processo em reactor fechado. Realizaram-se três ciclos de adição/degradação, tendo-se monitorizado em cada ciclo a CQO solúvel, os AGV e a produção de metano em diferentes intervalos de tempo. O consórcio anaeróbio tinha sido previamente aclimatado a ácido oleico. A eficiência de remoção da CQO solúvel aumentou ao longo da operação, os AGV totais diminuíram sucessivamente e a produção cumulativa de metano aumentou significativamente do primeiro para o terceiro ciclo. Estes resultados vêm confirmar que a chave para a degradação de efluentes com elevado conteúdo em lípidos reside na sequenciação das fases de acumulação na biomassa e degradação

    Biosorption and mineralization of a dairy wastewater under sequential operation mode

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    This work aimed to apply a sequential batch operation mode to promote the biomethanation of a real dairy wastewater enriched in fat. Three cycles were conducted with biomass previously acclimated to oleic acid. Soluble COD, VFA and methane content were analyzed in each cycle at different time intervals. The soluble COD removal efficiency improved slightly in each new feed and the total VFA levels detected decreased successively. The maximum cumulative methane production also improved from cycle 1 to cycle 3. These results contribute to support the idea that the key for the degradation of effluents with high lipid content is to sequence adsorption and degradation steps during the treatment process

    Dor visceral intensa associada a desnervação simpática renal seletiva: um desafio

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    Introdução e Objetivos: A desnervação simpática renal seletiva (DSRS) é um procedimento endovascular minimamente invasivo, seguro, recentemente desenvolvido para o tratamento da hipertensão resistente (HR). Até 6 ablações por radiofrequência (RF), com 2 minutos cada são aplicadas em ambas as artérias renais, estando associadas a dor abdominal visceral difusa, muito intensa1,2. Não foi encontrada literatura sobre o manuseamento anestésico deste procedimento. O nosso objetivo é descrever a experiência do nosso departamento na DSRS e sugerir uma abordagem anestésica (AA) adequada para o procedimento. Metodologia: Foram colhidos, retrospetivamente, os dados dos doentes com HR submetidos a DSRS na nossa instituição até novembro de 2012. Variáveis analisadas: dados demográficos, co-morbilidades, estadio físico da American Society of Anesthesiology (ASA-EF), abordagem anestésica e complicações peri-procedimento. Foi também realizada uma revisão bibliográfica na PubMed sobre DSRS e outros procedimentos endovasculares para identificar uma AA apropriada e eficiente para DSRS. Resultados: 16 doentes (9 homens/7 mulheres), idade 59,7 ± 10 anos. ASA-EF II 25%, III 75%. 14 doentes foram submetidos a cuidados anestésicos monitorizados (MAC): 6 com perfusão remifentanil (0.05 a 0.15μg/Kg/min com bólus até 1μ/Kg durante as ablações), 8 com bólus de propofol (até 150mg) associado a bólus de fentanil (até 150μg) e midazolam (1 a 2 mg). 1 doente foi sujeito a anestesia geral balanceada e 1 doente a bloqueio subaracnoideu. O procedimento anestésico durou 75 ± 16 minutos. O procedimento foi considerado bem sucedido em todos os doentes. Não foram observadas complicações. Discussão e Conclusão: Os 2 principais estudos publicados sobre DSRS (Simplicity trials) referem o uso de opiáceos e sedativos intravenosos para o tratamento da dor associada às ablações. Os fármacos usados e respetivas doses não são descritos. As várias AA usadas na nossa instituição refletem a ausência de literatura anestésica sobre a DSRS. A AA mais adequada depende das caraterísticas dos doentes e do tipo de dor associada (intensa, aguda e intermitente) e deve assegurar o máximo conforto do doente, segurança e sucesso técnico do procedimento. Pela nossa análise, a literatura revista e a experiência adquirida noutros procedimentos com dor semelhante consideramos que o remifentanil, pelas suas propriedades farmacológicas únicas, é adequado para o AA da DSRS. Remifentanil nas doses de 0.05 a 0.15μg/Kg/min com bólus até 1μ/Kg durante as ablações parece apropriado. São necessários mais estudos para melhor avaliação

    Functional properties of ceramic-Ag nanocomposite coatings produced by magnetron sputtering

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    In recent years, the use of nanocomposite materials to functionalize surfaces has been investigated, taking advantage of the complementary properties of the nanocomposite constituents. Among this family of materials, ceramic-Ag coatings have been widely studied due to the large variety of functionalities that silver possesses and the possibility of tuning the coating’s practical features by selecting the proper matrix to support this noble metal. Therefore, this review focuses on the effects of silver nanoparticles on the functional properties of ceramic-Ag nanocomposites. The chemistry, structure, morphology and topography of the coatings are analyzed with respect to the changes produced by the silver nanoparticles’ distribution, amount and sizes and by altering production process variables. To offer a clear understanding of the functionalities of these materials, the optical, electrical, mechanical, tribological, electrochemical and biological properties reported in the last decade are reviewed, focusing on the ability to tune such properties by modifying the silver distribution, morphology and composition. In particular, the surface plasmon resonance, self-lubricating ability and antibacterial effect of silver are covered in detail, establishing their correlation with factors such as silver diffusion, segregation and ionization.This research is partially sponsored by FEDER funds through the program COMPETE-Programa Operacional Factores de Competitividade and by Portuguese national funds through FCT-Fundação para a Ciência e a Tecnologia, under the projects ANTIMICROBCOAT - PTDC/CTM/102853/2008 and in the framework of the Strategic Projects PEST-C/FIS/UI607/2011, PEST-C/EME/UI0285/2011 and SFRH/BD/80947/2011. The authors would like to thank the ‘‘Surface Modification and Functionalization - Research Group (SMF)” for advice during the development of this review

    Structural and mechanical properties of nanocrystalline Zr co-sputtered a-C(:H) amorphous films

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    The aim of this study was to investigate the effect of Zr as alloying element to carbon films, particularly in respect to film structure and mechanical properties. The films were deposited by magnetron sputtering in reactive (Ar + CH4) and non-reactive (Ar) atmosphere with different Zr contents (from 0 to 14 at.%) in order to achieve a nanocomposite based films. With an increase of Zr content a broad peak was observed in X-ray diffraction spectra suggesting the presence of nanocrystalline (nc) ZrC phase for the coatings with Zr content higher than 4 at.%. The application of Scherrer formula yielded a grain sizes with a dimension of 1.0–2.2 nm. These results were supported by X-ray photoelectron spectroscopy showing typical charge transfer at Zr-C nanograins and carbon matrix interface. The nc-ZrC phase was also observed by transmission electron microscopy. The hardness of the coatings was approximately independent of Zr content. However, the Young modulus increased linearly. The residual stress of the coatings was strongly improved by the presence of nc-ZrC phase embedded in the a-C matrix. Finally, the incorporation of H into the matrix led to denser and harder films

    The association between fungi exposure and hypersensitivity pneumonitis: a systematic review

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    A systematic review of published studies focused on the association between hypersensitivity pneumonitis (HP) and fungi exposure was conducted on PubMed, following PRISMA guidelines for systematic reviews. A total of 14 studies met the inclusion criteria but only 6 of these studies were eligible, as the remaining 8 represented case reports that were separately included for further discussion. HP is an interstitial lung disease (ILD) characterized by a hypersensitization response to inhalable antigens and represents 1.5% to 12% of all ILD in the European population. Several fungi species that populate the indoor environment have been associated with the incidence of HP upon cumulative exposure, with Penicillium spp and Aspergillus spp being the fungi species most frequently associated with the onset of disease. Although some studies have shown that avoiding exposure to causative HP fungi tends to improve patients’ symptoms, other studies were unable to identify the source of sensitization. More microbial exposure studies are needed to properly estimate the risk of HP development in the built environment.This study has been performed in the framework of the EXALAR 21 project, which was funded by the European Regional Development Fund (FEDER), through the Competitiveness and Internationalization Operational Program, and by national funding from the Foundation for Science and Technology (FCT) under the reference info:eu-repo/grantAgreement/FCT/9471 - RIDTI/PTDC/GES-AMB/30193/2017/PT (POCI-01-0145-FEDER-030193, 02/SAICT/2017—Project n° 30193)

    Models and Estimation for Phylogenetic Trees

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    In this thesis, we consider Markov models for matched sequences. De¯ne fij(t) = P(X(t) = i; Y (t) = jjX(0) = Y (0)); where fij is the joint probability that, for a given site, the ¯rst and second sequences have the values i and j at a given site, given that they were the same at time 0. This can generalized to several sequences. The sequences (taxa) are then arranged in an evolutionary tree (phylogenetic tree) depicting how taxa diverge from their common ancestors. We develop tests and estimation methods for the parameters of di®erent models. Standard phylogenetic methods assume stationarity, homogeneity and reversibility for the Markov processes, and often impose further restrictions on the parameters. The parameters in these cases are estimated using many popular packages, including PHYLIP and PAUP*. We describe a new and more general method for calculating the joint probability distribution under stationary and homogeneous models for the more general models with some weakening of the stationarity and homogeneity assumptions. We describe the method for a two edged tree and then extend it to the case for a K tipped tree. We discuss the case of a ¯ve edged tree for a set of bacterial sequences for which stationarity and homogeneity are not present. This data set is very similar to that of Galtier and Gouy (1995), and the search for methods appropriate for its analysis has provided the raison d'etre for this work. The extension we propose is to allow non-stationarity, so that from the root of the tree we permit di®erent Markov processes to operate along different descendant lineages; furthermore, we permit non-homogeneous Markov processes to operate across the tree. We obtain methods tha
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