191 research outputs found

    Simulation Studies of Gas-Solid in the Riser of a Circulating Fluidized Bed

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    A numerical parametric study was performed on the influence of various riser exit geometries on the hydrodynamics of gas-solid two-phase flow in the riser of a Circulating Fluidized Bed (CFB). A Eulerian continuum formulation was applied to both phases. A two fluid framework has been used to simulate fully developed gas-solid flows in vertical riser. A two dimensional Computational Fluid Dynamics (CFD) model of gas-particle flow in the CFB has been investigated using the code FLUENT. The turbulence was modeled by a k-e turbulence model in the gas phase. The simulations were done using the geometrical configuration of a CFB test rig at the Universiti Teknologi Malaysia (UTM). The CFB riser column has 265 mm (width), 72 mm (depth) and 2.7 m height. The riser is made up of interchangeable Plexiglas columns. The computational model was used to simulate the riser over a wide range of operating and design parameters. In addition, several numerical experiments were carried out to understand the influence of riser end effects, particle size, gas solid velocity and solid volume fraction on the simulated flow characteristics. The CFD model with a k-e turbulence model for the gas phase and a fixed particle viscosity in the solids phase showed good mixing behaviour. These results were found to be useful in further development of modeling of gas solid flow in the riser

    Adaptation of yeasts to fructose rich environments: a role for horizontal gene transfer of a fructose transporter

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    Abstract of the poster presented 33rd Small Meeting on Yeast Transport and Energetics, 21-24 July 2015, Lisbon, Portugal

    Stepwise functional evolution in a fungal sugar transporter family

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    This is a pre-copyedited, author-produced version of an article accepted for publication in Molecular Biology and Evolution following peer review. The version of record Mol Biol Evol (2016) 33 (2): 352-366 is available online at: http://mbe.oxfordjournals.org/content/33/2/352 DOI 10.1093/molbev/msv220."Sugar transport is of the utmost importance for most cells and is important to a wide range of applied fields. However, despite the straightforward in silico assignment of many novel transporters, including sugar porters, to existing families, their exact biological role and evolutionary trajectory often remain unclear, mainly because biochemical characterization of membrane proteins is inherently challenging, but also owing to their uncommonly turbulent evolutionary histories. In addition, many important shifts in membrane carrier function are apparently ancient, which further limits our ability to reconstruct evolutionary trajectories in a reliable manner.Here we circumvented some of these obstacles by examining the relatively recent emergence of a unique family of fungal sugar facilitators, related to drug antiporters. The former transporters, named Ffz, were previously shown to be required for fructophilic metabolism in yeasts. We first exploited the wealth of fungal genomic data available to define a comprehensive but well-delimited family of Ffz-like transporters, showing that they are only present in Dikarya. Subsequently, a combination of phylogenetic analyses and in vivo functional characterization was used to retrace important changes in function, while highlighting the evolutionary events that are most likely to have determined extant distribution of the gene, such as horizontal gene transfers (HGTs). One such HGT event is proposed to have set the stage for the onset of fructophilic metabolism in yeasts, a trait that according to our results may be the metabolic hallmark of approximately one hundred yeast species that thrive in sugar rich environments."info:eu-repo/semantics/publishedVersio

    Patterns of fish community structure in protected and non-protected marine areas of mainland Tanzania

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    Information on the benefits of Marine Protected Areas (MPAs) for the condition of fish stocks is not well documented in Tanzania. Fish landing sites located in Tanga and Mtwara regions were surveyed to assess patterns of fish community structure; particularly fish abundance, species diversity, growth patterns, and maturity stages, based on catches landed at sites with different protection status. Fish abundance in the catch from protected areas was significantly lower than in non-protected areas (p=0.002). Species diversity was relatively higher in catches from non-protected (H=2.742) compared to protected areas (H=2.232). A high percentage of species (63.24 %) exhibiting negative allometric growth was observed in catches from non-protected areas. Further, a large number of mature fish was observed in catches from protected areas compared to non-protected areas (p<0.01). These indices are useful indicators of the performance of MPAs. The observed negative allometric growth and reduced number of mature fishes in the non-protected areas suggest that extractive pressure and disturbances from fishing gears have negative impacts on the fish stock. Continued high extraction may induce a decline in general fish size due to the constant selection for large-trait fish specimens, potentially causing evolutionally change in morphological traits. In contrast, the lower abundance and species diversity from the protected areas reflected low catch effort as a result of regulated fishing pressure in MPAs, rather than indicating the actual diversity in the fish stocks in these protected waters. Based on these findings it is recommended that more regulatory strategies are implemented in non-protected waters to allow more time for fish to attain appropriate harvest sizes and to ensure the effective protection of marine resources

    Influence of the liquid phase content and presence of hydroxypropyl methyl cellulose on the properties of a calcium phosphate bone cement

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    Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio

    Campanha "cuidar de quem cuida de nós" ou o estudo da saúde do bombeiro português: avaliação do impacto respiratório em corpos de 1ª intervenção de combate a incêndios (resultados de 2007)

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    Em Portugal, nos últimos 5 anos, arderam cerca de 1 milhão e 600 hectares de floresta. Cerca de 2/3 dos 40 000 bombeiros portugueses (BP) são voluntários e a sua saúde não é monitorizada. Os corpos de 1ª intervenção de combate aos incêndios estão expostos a uma enorme variedade de químicos e poluentes . Estudos recentes consideram a hipótese de que episódios repetidos de exposição ao fumo originam inflamação que pode estar na génese de aumento da reactividade brônquica e obstrução. Em 2007 iniciamos um programa médico de monitorização de saúde – MS – (Cuidar de quem cuida de nós) para avaliar o estado de saúde dos BP e o impacto respiratório nos corpos de 1.ª intervenção portugueses (C.1º), de modo a construir um perfil de saúde do BP e estimar o risco de lesão, estabelecer a prevalência de patologias respiratórias e elaborar normas/medidas. Sensibilizar a sociedade e implementar parcerias para assegurar MS BP. A avaliação médica respiratória do bombeiro consiste no autopreenchimento supervisionado de um questionário, realização de espirometria, aconselhamento médico de modificação de hábitos e referenciação médica se encontrada patologia. Estudámos 357 bombeiros, elementos dos C1.º de 44 corporações (CDOS Setúbal, Sintra, Guarda e Castelo Branco). Idade média de 33 anos (17-68); 13% sexo feminino e 87% sexo masculino. Hábitos tabágicos (HT: fumadores 47%, ex-fumadores 26%, não fumadores 26%. Exercício físico 41.5%, critério de treino físico 26.8%. Uso de equipamento de protecção : individual: 67,1%, respiratória (EPIR) : 38.3%. IMC >30-24,8%. Exposição referem 49,4%; exposição profissional outra que bombeiro 19%. Anos de actividade BP (AC)(até 5AC-30%, 6 a 10AC – 30%, 11 a 15AC – 15%). História prévia de doenças respiratórias em 17% ; sintomas respiratórios actuais pergunta “tem algum destes sintomas?”: dispneia (falta de ar 6,4%, dificuldade respiratória: quando anda rápido 12,8%; acompanhar 4,2%, na higiene 2,2%, no trabalho 1,7%) tosse e expectoração € (E 22%, E 2 meses/ano12,6%, E hemoptóica 1,4%), tosse ao levantar15,9%, deitado 7,5%), pieira 10,6% (no trabalho 3,9%). Espirometria (ESP) síndroma obstrutiva 6%, obstrução das pequenas vias aéreas 10,9%. Há relação P< 0,01 entre AC e alterações da ESP e independência nesta população entre HT e alterações da espirometria. Conclusões: A existência de alterações da espirometria e sintomas numa população jovem impõe a necessidade de vigilância respiratória anual e – mudança de hábitos (tabágicos, uso de EPIR diminuição de peso e aumento dos níveis de exercício físico) o que preconfigura a necessidade da criação/manutenção de um sistema de vigilância e monitorização sistemática dos bombeiros

    Tuberculose Pulmonar na Urgência Geral: impacto e abordagem

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    ‘New Medicine Service’: supporting adherence in people starting a new medication for a long-term condition: 26-week follow-up of a pragmatic randomised controlled trial

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    OBJECTIVE: To examine the effectiveness and cost-effectiveness of the community pharmacy New Medicine Service (NMS) at 26 weeks. METHODS: Pragmatic patient-level parallel randomised controlled trial in 46 English community pharmacies. 504 participants aged ≥14, identified in the pharmacy when presenting a prescription for a new medicine for predefined long-term conditions, randomised to receive NMS (n=251) or normal practice (n=253) (NMS intervention: 2 consultations 1 and 2 weeks after prescription presentation). Adherence assessed through patient self-report at 26-week follow-up. Intention-to-treat analysis employed. National Health Service (NHS) costs calculated. Disease-specific Markov models estimating impact of non-adherence combined with clinical trial data to calculate costs per extra quality-adjusted life-year (QALY; NHS England perspective). RESULTS: Unadjusted analysis: of 327 patients still taking the initial medicine, 97/170 (57.1%) and 103/157 (65.6%) (p=0.113) patients were adherent in normal practice and NMS arms, respectively. Adjusted intention-to-treat analysis: adherence OR 1.50 (95% CI 0.93 to 2.44, p=0.095), in favour of NMS. There was a non-significant reduction in 26-week NHS costs for NMS: -£104 (95% CI -£37 to £257, p=0.168) per patient. NMS generated a mean of 0.04 (95% CI -0.01 to 0.13) more QALYs per patient, with mean reduction in lifetime cost of -£113.9 (-1159.4, 683.7). The incremental cost-effectiveness ratio was -£2758/QALY (2.5% and 97.5%: -38 739.5, 34 024.2. NMS has an 89% probability of cost-effectiveness at a willingness to pay of £20 000 per QALY. CONCLUSIONS: At 26-week follow-up, NMS was unable to demonstrate a statistically significant increase in adherence or reduction in NHS costs, which may be attributable to patient attrition from the study. Long-term economic evaluation suggested NMS may deliver better patient outcomes and reduced overall healthcare costs than normal practice, but uncertainty around this finding is high. TRIAL REGISTRATION NUMBER: NCT01635361, ISRCTN23560818, ISRCTN23560818, UKCRN12494

    Engineering the Controlled Assembly of Filamentous Injectisomes in E. coli K-12 for Protein Translocation into Mammalian Cells.

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    Bacterial pathogens containing type III protein secretion systems (T3SS) assemble large needle-like protein complexes in the bacterial envelope, called injectisomes, for translocation of protein effectors into host cells. The application of these molecular syringes for the injection of proteins into mammalian cells is hindered by their structural and genomic complexity, requiring multiple polypeptides encoded along with effectors in various transcriptional units (TUs) with intricate regulation. In this work, we have rationally designed the controlled expression of the filamentous injectisomes found in enteropathogenic Escherichia coli (EPEC) in the nonpathogenic strain E. coli K-12. All structural components of EPEC injectisomes, encoded in a genomic island called the locus of enterocyte effacement (LEE), were engineered in five TUs (eLEEs) excluding effectors, promoters and transcriptional regulators. These eLEEs were placed under the control of the IPTG-inducible promoter Ptac and integrated into specific chromosomal sites of E. coli K-12 using a marker-less strategy. The resulting strain, named synthetic injector E. coli (SIEC), assembles filamentous injectisomes similar to those in EPEC. SIEC injectisomes form pores in the host plasma membrane and are able to translocate T3-substrate proteins (e.g., translocated intimin receptor, Tir) into the cytoplasm of HeLa cells reproducing the phenotypes of intimate attachment and polymerization of actin-pedestals elicited by EPEC bacteria. Hence, SIEC strain allows the controlled expression of functional filamentous injectisomes for efficient translocation of proteins with T3S-signals into mammalian cells
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