2,372 research outputs found
Diabetes InsÃpida Como Causa de Febre
A Diabetes InsÃpida é uma das causas pouco habituais de febre de etiologia indeterminada. Descrevemos o caso de urna lactente internado aos nove meses de idade com febre, má progressão ponderal e atraso no desenvolvimento motor. As causas habituais destas situações foram excluÃdas por exames exaustivos. Alguns meses mais tarde constatámos o aparecimento de poliúria e polidipsia. A prova com desmopressina fez o diagnóstico de Diabetes InsÃpida Central que foi confirmada com a resposta à terapêutica
Sensores baseados em nanotubos de carbono funcionalizados por ligação não-covalente
A pesquisa na área dos nanomateriais de carbono, como os nanotubos de carbono (CNTs), tem crescido
muito rapidamente devido às suas propriedades térmicas, eletrónicas e mecânicas. Muitos esforços têm
sido realizados para aumentar a solubilidade destes materiais em diversos solventes e obter dispersões
estáveis. Uma das estratégias para dispersar os CNTs consiste na funcionalização quÃmica, que apresenta
como desvantagem a destruição da estrutura sp2 do carbono destes materiais. Neste últimos anos surgiram
vários estudos baseados na funcionalização não-covalente com o intuito de manter as suas propriedades
estruturais. Com este fim, tem sido utilizadas estruturas poliaromáticas substituÃdas como perilenos e
pirenos que podem estabelecer interações do tipo Ï€-Ï€ com a superfÃcie aromática dos CNTs ou do grafeno.
Neste trabalho pretende-se apresentar uma revisão bibliográfica da utilização da funcionalização nãocovalente
no desenvolvimento de sensores e biossensores eletroquÃmicos em substrato de materiais
nanoestruturados de carbono (MWCNTs, SWCNTs, grafeno)
Antileishmanial activity and evaluation of the mechanism of action of strychnobiflavone flavonoid isolated from Strychnos pseudoquina against Leishmania infantum
© 2015, Springer-Verlag Berlin Heidelberg. The present study aimed to investigate the in vitro antileishmanial activity of strychnobiflavone flavonoid against Leishmania infantum, as well as its mechanism of action, and evaluate the ex vivo biodistribution profile of the flavonoid in naive BALB/c mice. The antileishmanial activity (IC50 value) of strychnobiflavone against stationary promastigote and amastigote-like stages of the parasites was of 5.4 and 18.9 μM, respectively; with a 50% cytotoxic concentration (CC50) value of 125.0 μM on murine macrophages, resulting in selectivity index (SI) of 23.2 and 6.6, respectively. Amphotericin B, used as a positive control, presented SI values of 7.6 and 3.3 for promastigote and amastigote-like stages of L. infantum, respectively. The strychnobiflavone was also effective in reducing in significant levels the percentage of infected macrophages, as well as the number of amastigotes per macrophage, after the treatment of infected macrophages using the flavonoid. By using different fluorescent probes, we investigated the bioenergetics metabolism of L. infantum promastigotes and demonstrated that the flavonoid caused the depolarization of the mitochondrial membrane potential, without affecting the production of reactive oxygen species. In addition, using SYTOX® green as a fluorescent probe, the strychnobiflavone demonstrated no interference in plasma membrane permeability. For the ex vivo biodistribution assays, the flavonoid was labeled with technetium-99m and studied in a mouse model by intraperitoneal route. After a single dose administration, the scintigraphic images demonstrated a highest uptake by the liver and spleen of the animals within 60 min, resulting in low concentrations after 24 h. The present study therefore demonstrated, for the first time, the antileishmanial activity of the strychnobiflavone against L. infantum, and suggests that the mitochondria of the parasites may be the possible target organelle. The preferential distribution of this compound into the liver and spleen of the animals could warrant its employ in the treatment of visceral leishmaniasis.This work was supported by grants from Instituto Nacional de Ciência e Tecnologia em Nanobiofarmacêutica (INCT-Nanobiofar), FAPEMIG (CBB-APQ-00819-12), CNPq (APQ-472090/2011-9, APQ- 482976/2012-8, and APQ-488237/2013-0) and São Paulo State Research Fundation (FAPESP 2012/18756-1). MACF is a grant recipient of FAPEMIG/CAPES. EAFC, VNC and AGT are grant recipient of CNPqPeer Reviewe
Vestas V90-3MW Wind Turbine Gearbox Health Assessment Using a Vibration-Based Condition Monitoring System
Reliable monitoring for the early fault diagnosis of gearbox faults is of great concern for the wind industry.This paper presents a novel approach for health condition monitoring (CM) and fault diagnosis in wind turbine gearboxes using vibration analysis. This methodology is based on amachine learning algorithm that generates a baseline for the identification of deviations fromthe normal operation conditions of the turbine and the intrinsic characteristic-scale decomposition (ICD) method for fault type recognition. Outliers picked up during the baseline stage are decomposed by the ICD method to obtain the product components which reveal
the fault information.The new methodology proposed for gear and bearing defect identification was validated by laboratory and field trials, comparing well with the methods reviewed in the literature
Glauber Critical Dynamics: Exact Solution of the Kinetic Gaussian Model
In this paper, we have exactly solved Glauber critical dynamics of the
Gaussian model on three dimensions. Of course, it is much easy to apply to low
dimensional case. The key steps are that we generalize the spin change
mechanism from Glauber's single-spin flipping to single-spin transition and
give a normalized version of the transition probability . We have also
investigated the dynamical critical exponent and found surprisingly that the
dynamical critical exponent is highly universal which refer to that for one-
two- and three-dimensions they have same value independent of spatial
dimensionality in contrast to static (equilibrium) critical exponents.Comment: 9 page
Solvable Kinetic Gaussian Model in External Field
In this paper, the single-spin transition dynamics is used to investigate the
kinetic Gaussian model in a periodic external field. We first derive the
fundamental dynamic equations, and then treat an isotropic d-dimensional
hypercubic lattice Gaussian spin system with Fourier's transformation method.
We obtain exactly the local magnetization and the equal-time pair correlation
function. The critical characteristics of the dynamical, the complex
susceptibility, and the dynamical response are discussed. The results show that
the time evolution of the dynamical quantities and the dynamical responses of
the system strongly depend on the frequency and the wave vector of the external
field.Comment: 11 page
Interorganizational information acquisition in an innovative SME network: innovation and information types
Information and innovation have been increasingly recognised as sources for firms’ competitive advantage. One of the ways firms have used to acquire these resources is through cooperative relationships, such as networks. This research proposes a conceptual model of antecedents and consequences of the volume of relevant information acquisition and innovation generation in the context of a Portuguese Innovative SME Network. This is an exploratory descriptive study, conducted through a survey of 60 SMEs (34.9% of the population). The results showed that for most firms, the participation on the network does not contribute to the acquisition of relevant information from
other firms.info:eu-repo/semantics/acceptedVersio
Metastable states in the Blume-Emery-Griffiths spin glass model
We study the Blume-Emery-Griffiths spin glass model in presence of an
attractive coupling between real replicas, and evaluate the effective potential
as a function of the density overlap. We find that there is a region, above the
first order transition of the model, where metastable states with a large
density overlap exist. The line where these metastable states appear should
correspond to a purely dynamical transition, with a breaking of ergodicity.
Differently from what happens in p-spin glasses, in this model the dynamical
transition would not be the precursor of a 1-step RSB transition, but
(probably) of a full RSB transition.Comment: RevTeX, 4 pages, 2 fig
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