560 research outputs found
The Noncommutative Harmonic Oscillator based in Simplectic Representation of Galilei Group
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
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
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Complex Perinatal Syndromes Affecting Early Human Growth and Development: Issues to Consider to Understand Their Aetiology and Postnatal Effects.
Complex perinatal syndromes (CPS) affecting pregnancy and childhood, such as preterm birth, and intra- and extra-uterine growth restriction, have multiple, diverse contexts of complexity and interaction that determine the short- and long-term growth, health and development of all human beings. Early in life, genetically-guided somatic and cerebral development occurs alongside a psychism "in statu nascendi," with the neural structures subjected to the effects of the intra- and extra-uterine environments in preparation for optimal postnatal functioning. Different trajectories of fetal cranial and abdominal growth have been identified before 25 weeks' gestation, tracking differential growth and neurodevelopment at 2 years of age. Similarly, critical time-windows exist in the first 5-8 months of postnatal life because of interactions between the newborn and their environment, mother/care-givers and feeding practices. Understanding these complex relational processes requires abandoning classical, linear and mechanistic interpretations that are placed in rigid, artificial biological silos. Instead, we need to conduct longitudinal, interdisciplinary research and integrate the resulting new knowledge into clinical practice. An ecological-systemic approach is required to understand early human growth and development, based on a dynamic multidimensional process from the molecular or genomic level to the socio-economic-environmental context. For this, we need theoretical and methodological tools that permit a global understanding of CPS, delineating temporal trajectories and their conditioning factors, updated by the incorporation of new scientific discoveries. The potential to optimize human growth and development across chronological age and geographical locations - by implementing interventions or "treatments" during periods of greatest instability or vulnerability - should be recognized. Hence, it is imperative to take a holistic view of reproductive and perinatal issues, acknowledging at all levels the complexity and interactions of CPS and their sensitive periods, laying the foundations for further improvements in growth and development of populations, to maximize global human potential. We discuss here conceptual issues that should be considered for the development and implementation of such a strategy aimed at addressing the perinatal health problems of the new millenium
INTERPRETANDO O LÍQUOR – COMO DADOS EPIDEMIOLÓGICOS PODEM AJUDAR NO RACIOCÍNIO CLÍNICO
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
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)
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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