5,462 research outputs found
Absorption on horizon-wrapped branes
We compute the absorption cross section of space-time scalars on a static D2
rane, in global coordinates, wrapped on the S^2 of an AdS_2 X S^2 X CY_3
geometry. We discuss its relevance for the construction of the dual quantum
mechanics of Calabi-Yau black holes.Comment: 18 pages, 2 figure
Dhvar5 antimicrobial peptide (AMP) chemoselective covalent immobilization results on higher antiadherence effect than simple physical adsorption
Bacterial colonization and subsequent biofilm formation is still one of the major problems associated with medical devices. Antimicrobial peptides (AMP) immobilization onto biomaterials surface is a promising strategy to avoid bacterial colonization. However, a correct peptide orientation and exposure from the surface is essential to maintain AMP antimicrobial activity. This work aims to evaluate the effect of the immobilization on antibacterial activity of Dhvar5 (LLLFLLKKRKKRKY), an AMP with a head-to-tail amphipathicity. Dhvar5 was linked to thin chitosan coatings in i) a controlled orientation and exposure, testing covalent immobilization of its N- or C-terminus and using spacers with different lengths and flexibilities or in ii) a random orientation by physical adsorption. Chitosan coating was chosen due to its antimicrobial properties and readiness to be functionalized. Surface characterization demonstrated the chemoselective immobilization of the peptide with different spacers in a similar concentration (∼2 ng/cm2). Efficacy assays demonstrated that covalent immobilization of Dhvar5 exposing its cationic end, improves the chitosan coating antimicrobial effect by decreasing Methicillin-resistant Staphylococcus aureus (MRSA) colonization. This effect was enhanced when longer spacers were used independently of their flexibility. In opposite, immobilized Dhvar5 exposing its hydrophobic end has no effect on bacterial adhesion to chitosan, and when adsorbed in a random orientation even induces bacterial adhesion to chitosan coating.This work was financed by FEDER funds through the Programa Operacional Factores de Competitividade (COMPETE) and by Portuguese funds through FCT (Fundacao para a Ciencia e a Tecnologia) in the framework of the projects: PTDC/CTM/101484/2008; PEst-C/SAU/LA0002/2013; Pest-C/QUI/UI0081/2013. Fabiola Costa acknowledges FCT for the PhD grant SFRH/BD/72471/2010
First report of Meloidogyne naasi parasitizing turfgrass in Portugal
In an exploratory sampling of a football field in Porto, Portugal, the root-knot nematode, Meloidogyne naasi, previously unreported from the Iberian Peninsula, was detected. Diagnosis was based on the analysis of perineal patterns and esterase phenotypes of females excised from grass roots, morphometrics and molecular analysis (PCR with specific primers and analysis of partial 28S sequences obtained by amplification using the primers D2A/D3B) of second- stage juveniles (J2) extracted from soil. When collected in water, J2 aggregated into a worm-star. Endospores of Pasteuria penetrans were frequently found attached to the J2. To our knowledge, this is the first report of M. naasi in Portugal and in the Iberian Peninsula, and the first report of worm-star formation in Meloidogyne.The authors would like to thank Dr. M. Luísa Moura
and José F. Azevedo for collaboration in sampling
and sample processing. This work was supported by
the strategic program UID/BIA/04050/2019 (POCI01-0145-FEDER-007569), funded by national funds
through the Portuguese Foundation For Science and
Technology (FCT) I.P. and by the ERDF through the
COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI)
What do -ray bursts look like?
There have been great and rapid progresses in the field of -ray
bursts (denoted as GRBs) since BeppoSAX and other telescopes discovered their
afterglows in 1997. Here, we will first give a brief review on the
observational facts of GRBs and direct understanding from these facts, which
lead to the standard fireball model. The dynamical evolution of the fireball is
discussed, especially a generic model is proposed to describe the whole
dynamical evolution of GRB remnant from highly radiative to adiabatic, and from
ultra-relativistic to non-relativistic phase. Then, Various deviations from the
standard model are discussed to give new information about GRBs and their
environment. In order to relax the energy crisis, the beaming effects and their
possible observational evidences are also discussed in GRB's radiations.Comment: 10 pages, Latex. Invited talk at the Pacific Rim Conference on
Stellar Astrophysics, Hong Kong, China, Aug. 199
Characterisation of the fumarate hydratase repertoire in Trypanosoma cruzi.
Nifurtimox and benznidazole represent the only treatments options available targeting Chagas disease, the most important parasitic infection in the Americas. However, use of these is problematic as they are toxic and ineffective against the more severe stages of the disease. In this work, we used a multidisciplinary approach to characterise the fumarases from Trypanosoma cruzi, the causative agent of Chagas Disease. We showed this trypanosome expresses cytosolic and mitochondrial fumarases that via an iron-sulfur cluster mediate the reversible conversion of fumarate to S-malate. Based on sequence, biochemical properties and co-factor binding, both T. cruzi proteins share characteristics with class I fumarases, enzymes found in bacteria and some other protozoa but absent from humans, that possess class II isoforms instead. Gene disruption suggested that although the cytosolic or mitochondrial fumarase activities are individually dispensable their combined activity is essential for parasite viability. Finally, based on the mechanistic differences with the human (host) fumarase, we designed and validated a selective inhibitor targeting the parasite enzyme. This study showed that T. cruzi fumarases should be exploited as targets for the development of new chemotherapeutic interventions against Chagas disease
Informática em enfermagem: desenvolvimento de software livre com aplicação assistencial e gerencial
O presente estudo teve como objetivo desenvolver um sistema de informação em enfermagem com aplicação na assistência de enfermagem e no gerenciamento do serviço. O SisEnf - Sistema de Informação em Enfermagem - é um software livre composto pelo módulo assistencial de enfermagem: histórico, exame clínico e plano de cuidados; o módulo gerencial compõe-se de: escala de serviço, gestão de pessoal, indicadores hospitalares e outros elementos. O sistema foi implementado na Clínica Médica do Hospital Universitário Lauro Wanderley, da Universidade Federal da Paraíba. Tendo em vista a necessidade de aproximação entre usuário e desenvolvedor, e a constante mudança de requisitos funcionais durante o processo iterativo, foi adotado o método do processo unificado. O SisEnf foi desenvolvido sobre plataforma WEB e com emprego de software livre. Portanto, o trabalho desenvolvido procurou auxiliar o processo de trabalho da enfermagem que agora terá oportunidade de incorporar a tecnologia da informação na sua rotina de trabalho.El presente estudio tuvo como objetivo desarrollar un sistema de información de enfermería con aplicación en la atención y en el gerenciamiento del servicio. El SisEnf -Sistema de Información en Enfermería- es un software libre compuesto por: a) el módulo asistencial de enfermería: historias clínicas, exámenes clínicos y plan de atención; y b) el módulo de gerenciamiento, que se compone de: escala de servicio, gestión de personal, indicadores hospitalarios y otros elementos. El sistema se puso en práctica en Clínica Médica en el Hospital Universitario Lauro Wanderley de la Universidad Federal de Paraíba. En vista de la necesidad de aproximación entre usuarios y desarrolladores y del cambio constante de las necesidades funcionales durante el proceso iterativo, fue adoptado el método de proceso unificado. El SisEnf fue desarrollado sobre una plataforma WEB con empleo de software libre. En conclusión, el trabajo desarrollado procura brindar auxilio en el proceso de trabajo de enfermería, que ahora tendrá la oportunidad de incorporar a la tecnología de la información en su rutina de trabajo.This study aimed at developing an information system in nursing with the implementation of nursing care and management of the service. The SisEnf - Information System in Nursing - is a free software module that comprises the care of nursing: history, clinical examination and care plan; the management module consists of: service shifts, personnel management, hospital indicators and other elements. The system was implemented at the Medical Clinic of the Lauro Wanderley University Hospital, at Universidade Federal da Paraiba. In view of the need to bring user and developer closer, in addition to the constant change of functional requirements during the interactive process, the method of unified process was used. The SisEnf was developed on a WEB platform and using free software. Hence, the work developed aimed at assisting in the working process of nursing, which will now have the opportunity to incorporate information technology in their work routine
Desvio fonológico e alterações práxicas orofaciais e do sistema estomatognático
OBJETIVO: verificar, bem como relacionar entre si, o desempenho de crianças com Desvio Fonológico e com Desenvolvimento Fonológico Típico na avaliação do Sistema Estomatognático e em testes de habilidades práxicas orofaciais avaliando suas habilidades práxicas orofaciais. MÉTODOS: amostra constituiu-se de 50 sujeitos, com idades entre quatro e oito anos, com Desvio Fonológico e com Desenvolvimento Fonológico Típico. Avaliou-se a fonologia por meio do instrumento Avaliação Fonológica da Criança e a gravidade do desvio por meio do Percentual de Consoantes Corretas. Posteriormente, aplicou-se a Avaliação do sistema estomatongático e o The Orofacial Praxis Test, para avaliar as habilidades práxicas orofaciais. Os dados foram tabulados e submetidos a tratamento estatístico, considerando-se p<0,05. RESULTADOS: com relação ao sistema estomatongático, observou-se diferença estatística entre os grupos apenas nas tarefas de assobio, contração e vibração de lábios e de língua, apresentando desempenho inferior as crianças com Desvio Fonológico. O mesmo foi observado quanto à postura de língua na sucção. As médias obtidas nas tarefas de habilidades práxicas orofaciais realizadas após Imitação foram melhores que após Solicitação Verbal, para todas as idades. Ainda, as crianças com menor idade apresentaram mais alterações que as crianças maiores, da mesma forma que as crianças com Desvio Fonológico apresentaram mais dificuldades que aquelas sem alterações de fala. CONCLUSÃO: as crianças com Desvio Fonológico apresentaram mais alterações do sistema estomatognático e das habilidades práxicas orofaciais que aquelas com Desenvolvimento Fonológico Típico, havendo melhora no desempenho com o avanço da idade e encontrando-se estas alterações relacionadas com as alterações de fala
The a-theorem and conformal symmetry breaking in holographic RG flows
We study holographic models describing an RG flow between two fixed points
driven by a relevant scalar operator. We show how to introduce a spurion field
to restore Weyl invariance and compute the anomalous contribution to the
generating functional in even dimensional theories. We find that the
coefficient of the anomalous term is proportional to the difference of the
conformal anomalies of the UV and IR fixed points, as expected from anomaly
matching arguments in field theory. For any even dimensions the coefficient is
positive as implied by the holographic a-theorem. For flows corresponding to
spontaneous breaking of conformal invariance, we also compute the two-point
functions of the energy-momentum tensor and the scalar operator and identify
the dilaton mode. Surprisingly we find that in the simplest models with just
one scalar field there is no dilaton pole in the two-point function of the
scalar operator but a stronger singularity. We discuss the possible
implications.Comment: 50 pages. v2: minor changes, added references, extended discussion.
v3: we have clarified some of the calculations and assumptions, results
unchanged. v4: published version in JHE
- …