560 research outputs found

    The Noncommutative Harmonic Oscillator based in Simplectic Representation of Galilei Group

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    In this work we study symplectic unitary representations for the Galilei group. As a consequence the Schr\"odinger equation is derived in phase space. The formalism is based on the non-commutative structure of the star-product, and using the group theory approach as a guide a physical consistent theory in phase space is constructed. The state is described by a quasi-probability amplitude that is in association with the Wigner function. The 3D harmonic oscillator and the noncommutative oscillator are studied in phase space as an application, and the Wigner function associated to both cases are determined.Comment: 7 pages,no figure

    Effect of voriconazole on Candida tropicalis biofilms: Relation with ERG genes expression

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    Candida tropicalis has emerged as the third most prevalent fungal pathogens and its ability to form biofilms has been considered one of the most important virulence factors, since biofilms represent high tolerance to antifungal agents. However, the mechanisms of C. tropicalis biofilm resistance to antifungals remain poorly understood. Thus, the main aim of this work was to infer about the effect of voriconazole on the formation and control of C. tropicalis biofilms and disclose its relationship with ERG genes' expression. Planktonic cells tolerance of several C. tropicalis clinical isolates to voriconazole was determined through of antifungal susceptibility test, and the effect of this azole against C. tropicalis biofilm formation and pre-formed biofilms was evaluated by cultivable cells determination and total biomass quantification. ERG genes expression was analyzed by quantitative real-time polymerase chain reaction. This work showed that C. tropicalis resistance to voriconazole is strain dependent and that voriconazole was able to partially control biofilm formation, but was unable to eradicate C. tropicalis pre-formed biofilms. Moreover, C. tropicalis biofilms resistance to voriconazole seems to be associated with alterations of sterol content in the cell membrane, resulting in ERG genes overexpression. Voriconazole is unable to control C. tropicalis biofilms, and the overexpression of ERG genes is a possible mechanism of biofilm resistance.TheauthorsthanktheFCTfortheStrategic Project of the UID/BIO/04469/2013 unit, FCT and European Union funds (FEDER/COMPETE) for the project RECI/BBBEBI/0179/2012 (FCOMP-01-0124-FEDER-027462). We also would like to acknowledge Pfizer , S.A. for the kindly donation of voriconazole

    INTERPRETANDO O LÍQUOR – COMO DADOS EPIDEMIOLÓGICOS PODEM AJUDAR NO RACIOCÍNIO CLÍNICO

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    Introdução: A meningite bacteriana sofreu grandes mudanças epidemiológicas após a introdução dos antibióticos e vacinas, passando de uma condição letal para tratável e prevenível. Compreender essas mudanças no perfil epidemiológico em nível local permitem planejar estratégias de terapia empírica. As alterações de líquor possuem papel fundamental nessa avaliação. Metodologia: Foi realizado um estudo transversal dos casos notificados de meningite entre janeiro de 2010 e junho de 2015 no Complexo Hospital de Clínicas – Universidade Federal do Paraná. Foram analisados a celularidade e citologia do líquor e os agentes etiológicos. Para as etiologias bacterianas, foi avaliado dados epidemiológicos. Resultados: Foram notificados 504 casos de meningite no período avaliado. A meningite asséptica foi a classificação epidemiológica mais comum. As meningites bacterianas com confirmação etiológica causadas por Neisseria meningitidis, Streptococcus pneumoniae ou Haemophilus influenzae ocorreram em 8,7% dos casos notificados, sendo que 30% delas ocorreram em menores de 1 ano. A N. meningitidis correspondeu a 61% desses casos, enquanto que S. pneumoniae a 34%. As meningites neutrofílicas com mais de 75% de neutrófilos são causadas por tais bactérias em mais da metade (53%). A meningite asséptica é a segunda principal etiologia (20%) seguida de perto pela meningite tuberculosa (17%). Os casos de meningite meningocócica se concentram em crianças até 1 ano (56% dos casos), a meningite pneumocócica se concentra nos adultos entre 18 e 50 anos (46%) e idosos (27%). Conclusões: O conhecimento da epidemiologia local através da interpretação do líquor, somada à avaliação da faixa etária são importantes aliados da avaliação clínica para determinação do agente etiológico mais provável e podem ajudar na decisão terapêutica

    New trends in peptide-based anti-biofilm strategies : a review of recent achievements and bioinformatics approaches

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    Antimicrobial peptides (AMPs) have a broad spectrum of activity and unspecific mechanisms of action. Therefore, they are seen as valid alternatives to overcome clinically relevant biofilms and reduce the chance of acquired resistance. This paper reviews AMPs and anti-biofilm AMP-based strategies and discusses ongoing and future work. Recent studies report successful AMP-based prophylactic and therapeutic strategies, several databases catalogue AMP information and analysis tools, and novel bioinformatics tools are supporting AMP discovery and design. However, most AMP studies are performed with planktonic cultures, and most studies on sessile cells test AMPs on growing rather than mature biofilms. Promising preliminary synergistic studies have to be consubstantiated and the study of functionalized coatings with AMPs must be further explored. Standardized operating protocols, to enforce the repeatability and reproducibility of AMP anti-biofilm tests, and automated means of screening and processing the ever-expanding literature are still missing.Financial support from IBB-CEB and Fundacao para a Ciencia e Tecnologia (FCT) and European Community fund FEDER, through Program COMPETE, in the ambit of the FCT project 'PTDC/SAU-SAP/113196/2009/ FCOMP-01-0124-FEDER-016012' is gratefully acknowledged

    Comparative study on the use of specific and heterologous microsatellite primers in the stingless bees Melipona rufiventris and M. mondury (Hymenoptera, Apidae)

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    Due to their high degree of polymorphism, microsatellites are considered useful tools for studying population genetics. Nevertheless, studies of genetic diversity in stingless bees by means of these primers have revealed a low level of polymorphism, possibly the consequence of the heterologous primers used, since in most cases these were not specifically designed for the species under consideration. Herein we compared the number of polymorphic loci and alleles per locus, as well as observed heterozygosity in Melipona rufiventris and M. mondury populations, using specific and heterologous primers. The use of specific primers placed in evidence the greater frequency of polymorphic loci and alleles per locus, besides an expressive increase in observed heterozygosity in M. rufiventris and M. mondury, thereby reinforcing the idea that populational studies should be undertaken by preferably using species-specific microsatellite primers
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