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    85188 research outputs found

    Genetic variability of Candida albicans SAP8 propeptide in isolates from different types of infection

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    The secreted aspartic proteases (Saps) are among the most studied virulence determinants in Candida albicans. These proteins are translated as pre-pro-enzymes consisting of a signal sequence followed by a propeptide and the mature enzyme. The propeptides of secreted proteinases are important for the correct processing, folding/secretion of the mature enzyme. In this study, the DNA sequences of C. albicans Saps were screened and a microsatellite was identified in SAP8 propeptide region. The genetic variability of the repetitive region of Sap8 propeptide was determined in 108 C. albicans independent strains isolated from different types of infection: oral infection (OI), oral commensal (OC), vulvovaginal candidiasis (VVC), and bloodstream infections (BSI). Nine different propeptides for Sap8 processing were identified whose frequencies varied with the type of infection. OC strains presented the highest gene diversity while OI isolated the lowest. The contribution of the Saps to mucosal and systemic infections has been demonstrated and recently Sap8 has been implicated in the cleavage of a signalling glycoprotein that leads to Cek1-MAPK pathway activation. This work is the first to identify a variable microsatellite in the propeptide of a secreted aspartic protease and brings new insights into the variability of Sap8.This research was supported by FEDER funds through the Operational Programme COMPETE and national funds through Fundação para a Ciência e Tecnologia (FCT), in the scope of project PEst-OE/BIA/UI4050/

    Computation of a three-dimensional flow in a square microchannel: a comparison between a particle method and a finite volume method

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    Traditional grid-based numerical methods, such as finite volume method (FVM), are not suitable to simulate multiphase biofluids (such as blood) at the microscale level. Alternatively, meshfree Lagrangian methods can deal with two or more finely dispersed phases moving relatively to each other. The Moving Particle Semi-Implicit Method (MPS), used in this study, is a deterministic particle method based on a Lagrangian technique to simulate incompressible flows. The advantages of particle methods over traditional grid-based numerical methods have motivated several researchers to implement them into a wide range of studies in computational biomicrofluidics. The main aim of this paper is to evaluate the accuracy of the MPS method by comparing it with numerical simulations performed by an FVM. Hence, simulations of a Newtonian fluid flowing through a constriction were performed for both methods. For the MPS, a section of the channel of 3011.511.5 m was simulated using periodic boundary conditions. The obtained results have provided indications that, if the initial particle distance is sufficiently small, the MPS method can calculate accurately velocity profiles in the proposed channel.The authors acknowledge the financial support provided by PTDC/SAU-ENB/116929/2010 and EXPL/EMSSIS/2215/2013 from FCT (Science and Technology Foundation), COMPETE, QREN and European Union (FEDER). D. Bento acknowledge the financial support provided by SFRH/BD/91192/2012 from FCT (Science and Technology Foundation), COMPETE, QREN and European Union (FEDER). The authors are also very grateful to Dr. Alberto Gambaruto (Bristol University) for helpful explanations and suggestions regarding the MPS

    Raychaudhuri equation in spacetimes with torsion

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    Given a spacetime with nonvanishing torsion, we discuss the equation for the evolution of the separation vector between infinitesimally close curves in a congruence. We show that the presence of a torsion field leads, in general, to tangent and orthogonal effects on the congruence; in particular, the presence of a completely generic torsion field contributes to a relative acceleration between test particles. We derive, for the first time in the literature, the Raychaudhuri equation for a congruence of timelike and null curves in a spacetime with the most generic torsion field.The Authors wish to thank José P. S. Lemos for early discussions on a first version of the paper. We thank FCT-Portugal for financial support through Project No. PEst-OE/FIS/UI0099/2015. PL thanks IDPASC and FCT-Portugal for financial support through Grant No. PD/BD/114074/2015. VV is supported by the FCTPortugal grant SFRH/BPD/77678/

    Analysis of human performance as a measure of mental fatigue

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    In our day to day, we often experience a sense of being tired due to mental or physical workload. Along with that, there is also a feeling of degrading performance, even after the completion of simple tasks. These mental states however, are often not felt consciously or are ignored. This is an attitude that may result in human error, failure, and may lead to potential health problems together with a decrease in quality of life. States of acute mental fatigue may be detected with the close monitoring of certain indicators, such as productivity, performance and health indicators. In this paper, a model and prototype are proposed to detect and monitor acute acute fatigue, based on non-invasive Humancomputer Interaction (HCI). This approach will enable the development of better working environments, with an impact on the quality of life and the work produced.This work was developed in the context of the project CAMCoF - Contextaware Multimodal Communication Framework funded by ERDF - European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT - Funda ção para a Ciência e a Tecnologia (Portuguese Foundation for Science and Technology) within project FCOMP-01-0124-FEDER-028980

    Use of a fluorescence-based approach to assess short-term responses of the alga Pseudokirchneriella subcapitata to metal stress

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    This work explores the use of fluorescent probes to evaluate the responses of the green alga Pseudokirchneriella subcapitata to the action of three nominal concentrations of Cd(II), Cr(VI), Cu(II) and Zn(II) for a short time (6 h). The toxic effect of the metals on algal cells was monitored using the fluorochromes SYTOX Green (SG, membrane integrity), fluorescein diacetate (FDA, esterase activity) and rhodamine 123 (Rh123, mitochondrial membrane potential). The impact of metals on chlorophyll a (Chl a) autofluorescence was also evaluated. Esterase activity was the most sensitive parameter. At the concentrations studied, all metals induced the loss of esterase activity. SG could be used to effectively detect the loss of membrane integrity in algal cells exposed to 0.32 or 1.3 mol L1 Cu(II). Rh123 revealed a decrease in the mitochondrial membrane potential of algal cells exposed to 0.32 and 1.3 mol L1 Cu(II), indicating that mitochondrial activity was compromised. Chl a autofluorescence was also affected by the presence of Cr(VI) and Cu(II), suggesting perturbation of photosynthesis. In conclusion, the fluorescence-based approach was useful for detecting the disturbance of specific cellular characteristics. Fluorescent probes are a useful diagnostic tool for the assessment of the impact of toxicants on specific targets of P. subcapitata algal cells.The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013. Manuela D. Machado gratefully acknowledges the post-doctoral grant from FCT (SFRH/BPD/72816/2010)

    Dextrin-based nanomagnetogel: in vivo biodistribution and stability

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    The biodistribution profile of a new dextrin nanomagnetogel, which consists on -Fe2O3 superparamagnetic nanoparticles loaded within a polymeric matrix of modified dextrin, was studied in mice. The nanomagnetogel bear a monomodal size distribution profile (average diameter 110 nm) close to neutral surface charge and higher relaxivity (r2 = 215-248 mM-1s-1 and r2/r1 = 13-11) than those of commercial formulations (r2 = 160-177 mM-1s-1 and r2/r1 = 4-7). Also the observed blood half-life - approximately 4 hours - is superior to that of similar commercially available formulations, which remain few minutes in circulation. Pegylation resulted in 1.7 and 1.2-fold lower accumulation in the liver and spleen, respectively, within the first 24 h. Noteworthy, a good correlation was obtained between the amount of polymer (quantified by scintigraphy) in the spleen, 48 h after administration, and the amount of iron physically loaded through hydrophobic interactions (quantified by ICP) indicating the absence of iron leakage from the polymeric matrix. This study provides evidence on the in vivo stability of a self-assembled nanomagnetogel, a much relevant feature which is seldom reported in the literature.The authors thank the Project “strong>BioHealth - Biotechnology and Bioengineering approaches to improve health quality”, Ref. NORTE-07-0124-FEDER-000027, co-funded by the Programa Operacional Regional do Norte (ON.2 O Novo Norte), QREN, FEDER. The authors thank the Magnisense Corporation for providing a MIAplex Reader and CFGCG the EU COST TD1004 Action “Theragnostics Imaging and Therapy”. The authors thank Professor Cidália Botelho for the iron analysis by Atomic Absorbance Spectroscopy at the Oporto University, Chemical Engineering Department. C. Gonçalves, J. P. Silva, J. A. Martins, and M. F. M. Ferreira acknowledge FCT Portugal, for postdoc grants SFRH/BPD/70524/2010 and SFRH/BPD/64958/2009, sabbatical grant SFRH/BSAB/ 1328/2013 and PhD grant SFRH/BD/63994/2009, respectively

    Reactivity of hydroxy-containing aromatic compounds towards electrogenerated hydroxyl radicals

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    A kinetic study on the oxidation of hydroxy-containing aromatic compounds by electrogenerated HO radical and simultaneous by direct electron transfer is presented. First order kinetics are used to describe consumption rates of hydroquinone, benzoic acid and of hydroxybenzoic acid derivatives by galvanostatic electrolysis with simultaneous oxygen evolution at a Pt electrode. Linear correlations were established from the effect of electrolyses current density on kapp. The meaning of the intercept and of the slope is analysed. A good agreement is found between intercept values and the apparent rate constants from potentiostatic electrolysis without O2 evolution. Simultaneously, the slopes magnitude corroborate the relative reactivity order of species that was established considering the occurrence of positive charge densities on carbon atoms of the aromatic ring. Therefore, the present analysis provides kinetic information concerning both, the direct electron-transfer and the reaction with HO radical.Thanks are due to FCT (Fundação para a Ciência e Tecnologia) and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU for financial support to the Research Centre, CQ/UM [PEst-C/QUI/UI0686/2011 (FCOMP-01-0124-FEDER- 022716)]. Raquel Oliveira thanks to FCT, POPH (Programa Operacional Potencial Humano) and FSE (Fundo Social Europeu) for the PhD Grant (SFRH/BD/64189/2009)

    Mutações do conto nas sociedades contemporâneas

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    GÉNERO ANCESTRAL, o conto tem exercido ao longo dos tempos a função social de transmitir a memória cultural, reinventando-se e readaptando- se continuamente a novas condições sociais, tecnológicas e ideológicas, nomeadamente as das sociedades pós-modernas. O ritmo, preocupações e formas de comunicação característicos da vida urbana e da cultura de massas contemporâneas levaram ao aparecimento de novas modalidades do conto, marcadas por hibridismos de vária ordem (linguísticos, culturais, genológicos), nos mais variados contextos de comunicação e nos mais diversos suportes físicos. Na intersecção do conto tradicional, da literatura e da cultura de massas, focando muitas vezes temáticas semelhantes e testemunhando das preocupações dos homens e mulheres das cidades contemporâneas, o conto transformou- -se e multiplicou-se, atravessando hoje as artes digitais e as “artes da rua”, os ecrãs de tablets e ipods, assim como os locais de encontro das nossas cidades.Fundação para a Ciência e a Tecnologia, UE, COMPETE, QRE

    Social rhythms and volume of social activity of people on methadone substitution program

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    CONTEXTO: Os ritmos circadianos no ser humano, para além de serem alinhados ou sincronizados por zeitgebers de natureza física, também são sincronizados por zeitgebers de natureza social. A alteração do zeitgebers expõe a pessoa a grandes possibilidades de adoecer. Diversas opiniões sugerem que pessoas dependentes de substâncias psicoativas ilícitas têm ritmos próprios que não se sincronizam com os ritmos da sociedade, nem com os ritmos biológicos. OBJETIVO: Descrever os ritmos sociais (MRS) e o nível de atividade social (INA) de pessoas em programa de substituição com metadona. METODOLOGIA: Participaram 47 sujeitos com dependência opiácea a frequentar um programa de substituição com metadona. Instrumentos: Métrica dos Ritmos Sociais; Índice de Graffar e Questionário de Dados Sociodemográficos e Clínicos. Todos os procedimentos éticos foram respeitados. Para a análise estatística recorreu-se ao IBM SPSS Statistics, versão 19.0. Foi considerado estatisticamente significativo um valor de p <.05. RESULTADOS: Os separados/divorciados possuíam maior INA, seguidos dos solteiros e casados. Os desempregados possuíam maior lNA que os empregados. Os empregados revelaram valores inferiores de MRS. Os sujeitos com "lhos apresentaram menor INA e MRS. Os sujeitos revelaram regularidade dos ritmos sociais, embora apresentassem muito baixo nível de atividade social. CONCLUSÕES: Para além das relações significativas com algumas variáveis sociodemográficas, os dados também dizem que os sujeitos apresentam ritmicidade social, embora com relações sociais pobres, o que indica uma diminuição da interação social, com as implícitas consequências negativas na saúde.CONTEXTO: Los ritmos circadianos en los seres humanos, así como estar alineados o sincronizados por zeitgebers de la naturaleza física (por ejemplo, ciclo de luz/oscuridad), también están sincronizados por zeitgebers naturaleza social. El alteración los zeitgebers expone la persona a las grandes posibilidades de enfermarse. Opiniones diversas sugieren que las personas dependientes de las drogas ilegales tienen sus propios ritmos que no se sincronizan con los ritmos de la sociedad y los ritmos biológicos OBJETIVO: Describir los ritmos sociales (MRS) y el nivel de actividad social (INA) de las personas en el programa de sustitución con metadona. METODOLOGÍA: 47 sujetos con dependencia de opiáceos integrados en un programa de sustitución con metadona. Instrumentos: Métrica de los Ritmos Sociales; Índice de Gra!ar e Cuestionario de Datos Socio Demográ"cos y Clínicos. Todos los procedimientos éticos fueron respetados. Para el análisis estadístico se utilizó el IBM SPSS Statistics, versión 19.0. Se consideró estadísticamente signi"cativo un valor de p < .05. RESULTADOS: Los separados/divorciados tuvieron mayor INA, seguido de solteros y casados. Los desempleados tenían una mayor actividad social que los empleados. Los empleados mostraron valores inferiores de MRS. Las personas con hijos tuvieron menor INA y MRS. Los sujetos mostraron regularidad de los ritmos sociales, aunque con muy bajo nivel de actividad social. CONCLUSIONES: Además de las relaciones signi"cativas con las variables sociodemográ"cas, los datos también decir que los individuos tienen la ritmicidad social, aunque con pobres relaciones sociales, lo que indica una disminución de la interacción social, con consecuencias negativas para la salud.BACKGROUND: Circadian rhythms in humans, as well as being aligned or synchronized by zeitgebers of physical nature, are also synchronized by zeitgebers of social nature. Changing the zeitgebers exposes the person to great possibilities of becoming ill. Several opinions suggest that people addicted to illicit psychoactive substances have their own rhythms that do not synchronize with the rhythms of society, nor with biological rhythms. AIM: To describe the Social Rhythms (SMR) and the social Activity Level Index (ALI) of people in methadone substitution program. METHODS: 47 subjects with opioid dependence attending a methadone substitution program. Instruments: Social Rhythms Metric; Gra!ar Index and Socio-Demographic and Clinical Data Questionnaire. All ethical procedures were respected. For statistical analysis we used the IBM SPSS Statistics, version 19.0. Was considered statistically signi"cant a p value < .05. RESULTS: #e separated/divorced had higher ALI, followed by single and married. #e unemployed had higher ALI than employees. Employees showed lower values of SMR. Individuals with children had lower ALI and SMR. #e subjects showed regularity of social rhythms, although showing very low level of social activity. CONCLUSIONS: In addition to the signi"cant relationships to sociodemographic variables, the data also show that individuals have social rhythmicity, although with poor social relationships, which indicates a decrease in social interaction, with implicit negative health consequences

    Fixed-bed column process as a strategy for separation and purification of Cephamycin C from fermented broth

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    Fixed-bed column processes using the anionic resin Q Sepharose XL were evaluated for Cephamycin C (CepC) purification from fermentation broth. Breakthrough and desorption curves were obtained for different flow rates (2.5, 5.0 and 7.5 mL/min). The elution method consisted of a stepwise gradient using NaCl solutions (0.1, 0.3 and 0.5%), which resulted in the separation of CepC from others antibiotics. The flow rate did not interfere on adsorption during loading of the column, but band broadening was observed during elution as the flow rate increased. After the ion exchange process, the fractions containing CepC were submitted to solid phase extraction using a C18 cartridge to remove salts. Analyses of the broth used to feed the column and of the salt-free fractions by LC-MS showed a reduction in the concentration of some contaminants (possibly penicillin N, deacetylcephalosporin C, and deacetoxycephalosporin C) compared to the concentration of CepC. In conclusion, ion exchange process followed by adsorption on a C18 adsorbent was demonstrated to be a selective and efficient procedure to purify CepC from fermentation broth.The authors acknowledge CAPES, CNPq, and FAPESP for the financial support


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