3,422 research outputs found
Entrevista com o professor Carlos Algusto de Figueredo Monteiro
No full textEntrevista com o professor Carlos Algusto de Figueredo Monteir
Entrevista com o professor Carlos Algusto de Figueredo Monteiro
No full textEntrevista com o professor Carlos Algusto de Figueredo Monteir
Métodos y estrategias para la deteccion de bovinos persistentemente infectados con el virus de diarrea viral bovina (DVB)
No full textManejo neuroquirúrgico de los aneurismas intracraneales:análisis de los factores que influyen en el resultado final
No full textSin duda alguna que el desarrollo de la microcirugía y otros avances, han permitido al neurocirujano ampliar notablemente el horizonte quirúrgico en el tratamiento de los aneurismas intracraneales. En el presente trabajo nuestro propósito es realizar una revisión de la experiencia acumulada en más de 15 años, analizando como influyen los problemas en el diagnóstico clínico e imagenológico, el tratamiento inicial y la cirugía en lograr la reducción máxima posible de la morbilidad y mortalidad de esta enfermedad. En un medio neuroquirúrgico adecuado con acceso a tecnología moderna se puede reducir la mortalidad a menos del 10% (9.09%), incluyendo casos con aneurismas complejos. Este trabajo se basa en un estudio descriptivo de 77 pacientes portadores de 101 aneurismas intracraneales intervenidos quirúrgicamente en el Centro de Investigaciones Médico Quirúrgicas (CIMEQ), desde 1994 hasta el 2003. Se establecieron para el análisis factores favorables y de riesgo relacionados con la enfermedad y su tratamiento: edad, sexo, existencia de otras enfermedades asociadas, el estado neurológico al ingreso, la intensidad de la hemorragia, la cantidad de aneurismas encontrados en cada enfermo, la localización y anatomía quirúrgica del saco, la presencia de complicaciones pre, trans y postoperatorias, el tiempo entre el diagnóstico de la enfermedad y la realización del proceder quirúrgico, así como el empleo de coadyuvantes en la cirugía. Se concluye que aún no se realiza adecuadamente el diagnóstico inicial de la hemorragia subaracnoidea (HSA); la realización del estudio angiográfico completo aún es demorado y la remisión del paciente a un centro para la atención definitiva es tardía, impidiendo la realización de la operación en etapa temprana. Lo que ocurre durante la intervención quirúrgica es definitorio en el resultado final por lo que se hace necesario contar con los elementos técnicos necesarios: microcirugía, instrumental adecuado, surtido de grapas y otros métodos coadyuvantes, que permitan obtener un resultado quirúrgico óptimo de exclusión total aneurisma, manteniendo la circulación cerebral. Se presenta un protocolo para el tratamiento de la enfermedad aneurismática que puede ser utilizado según las condiciones y posibilidades de los diferentes servicios de neurocirugía del país
Antifungal susceptibility of Malassezia pachydermatis biofilm.
No full textAntifungal resistance has been associated with biofilm formation in many microorganisms, but not yet in Malassezia pachydermatis. This saprophytic yeast can cause otitis and dermatitis in dogs and has emerged as an important human pathogen, responsible for systemic infections in neonates in intensive care units. This study aims to evaluate the in vitro antifungal susceptibility of M. pachydermatis strains, in both their planktonic and sessile forms, to fluconazole, miconazole, ketoconazole, itraconazole, posaconazole, terbinafine and voriconazole using the XTT assay and Clinical and Laboratory Standards Institute (CLSI) microdilution method. The minimum inhibitory concentration (MIC) values recorded for each drug were significantly higher for sessile cells relative to planktonic cells to the extent that ≥ 90% of M. pachydermatis strains in their sessile form were classified as resistant to all antifungal agents tested. Data suggest that M. pachydermatis biofilm formation is associated with antifungal resistance, paving the way towards investigating drug resistance mechanisms in Malassezia spp
NiO-nanoflowers decorating a plastic electrode for the non-enzymatic amperometric detection of H2O2 in milk: old issue, new challenge
No full textIn food supply chain, there are regulatory limitations on the use of chemicals for cleaning processing lines
since the healthiness of the commodities must be guaranteed if accidentally traces of these detergents and
sanitizers pass to them. Hydrogen peroxide, is a commonly used sanitizer in the cleaning of the food
processing lines having both bactericidal and bacteriostatic properties, however, it produces inflammatory
effects on the human body. The availability of rapid systems to detect its accidental presence is therefore
useful to speed up the control and apply corrective actions. In the present work, a drop casting and easily
prepared plastic graphite / PVC electrode decorated with NiO nanostructures has been investigated as
electrochemical sensor for the non-enzymatic amperometric determination of H2O2. 24 The catalytic activity,
dispersion, and stability of NiO nanostructures mixed with plastic nanocomposite electrode have been studied
in detail. The preparation method, particularly the precipitating agents used in the synthesis of NiO
nanostructures strongly influenced their morphology and porosity. Further, the electrochemical response of
NiO-PE electrodes towards H2O2 resulted to be morphology-dependent. The non-enzymatic electrochemical
sensor was optimized for the rapid and sensitive detection of H2O2 present in milk with no sample pre-
treatments. NiO nanoflowers showed the best catalytic activity towards H2O2, a linear range that extends up
to 4 mM and a LOD of 5 μM (3sd of the blank signal) were obtained
Stability improvement of the fatty acid binding protein Sm14 from S. mansoni by Cys replacement: Structural and functional characterization of a vaccine candidate
No full textThe Schistosoma mansoni fatty acid binding protein (FABP), SmA, is a vaccine candidate against, S. mansoni and F hepatica. Previously, we demonstrated the importance of a correct fold to achieve protection in immunized animals after cercariae challenge [[10]. C.R.R. Ramos, R.C.R. Figueredo, T.A. Pertinhez, M.M. Vilar, A.L.T.O. Nascimento, M. Tendler, I. Raw, A. Spisni, P.L. Ho, Gene structure and M20T polymorphism of the Schistosoma mansoni Sm14 fatty acid-binding protein: structural, functional and immunoprotection analysis. J. Biol. Chem. 278 (2003) 12745-12751]. Here we show that the reduction of vaccine efficacy over time is due to protein dimerization and subsequent aggregation. We produced the mutants Sm14-M20(C62S) and Sm14M20(C62V) that, as expected, did not dimerize in SDS-PAGE. Molecular dynamics calculations and unfolding experiments highlighted a higher structural stability of these mutants with respect to the wild-type. In addition, we found that the mutated proteins, after thermal denaturation, refolded to their active native molecular architecture as proved by the recovery of the fatty acid binding ability. Sm14-M20(C62V) turned out to be the more stable form over time, providing the basis to determine the first 3D solution structure of a Sm14 protein in its apo-form. Overall, Sm14-M20(C62V) possesses an improved structural stability over time, an essential feature to preserve its immunization capability and, in experimentally immunized animals, it exhibits a protection effect against S. mansoni cercariae infections comparable to the one obtained with the wild-type protein. These facts indicate this protein as a good lead molecule for large-scale production and for developing an effective Sm14 based anti-helminthes vaccine. (C) 2008 Elsevier B.V. All rights reserved.CAPESCNPqFAPESPFINEPALVOSFiocruz-RJ and Fundacao Butanta
NiO-nanoflowers decorating a plastic electrode for the non-enzymatic amperometric detection of H2O2 in milk: Old issue, new challenge
No full textIn food supply chain, there are regulatory limitations on the use of chemicals for cleaning processing lines since the healthiness of the commodities must be guaranteed if accidently traces of these detergents and sanitizers pass to them. Hydrogen peroxide, is a commonly used sanitizer in the cleaning of the food processing lines having both bactericidal and bacteriostatic properties, however, it produces inflammatory effects on the human body. The availability of rapid systems to detect its accidental presence is therefore useful to speed up the control and apply corrective actions. In the present work, a drop casting and easily prepared plastic graphite/PVC electrode decorated with NiO nanostructures has been investigated as electrochemical sensor for the non-enzymatic amperometric determination of H2O2. The catalytic activity, dispersion, and stability of NiO nanostructures mixed with plastic nanocomposite electrode have been studied in detail. The preparation method, particularly the precipitating agents used in the synthesis of NiO nanostructures strongly influenced their morphology and porosity. Further, the electrochemical response of NiO-PE electrodes towards H2O2 resulted to be morphology-dependent. The non-enzymatic electrochemical sensor was optimized for the rapid and sensitive detection of H2O2 present in milk with no sample pre-treatments. NiO nanoflowers showed the best catalytic activity towards H2O2, a linear range that extends up to 4 mM and a LOD of 5 μM (3sd of the blank signal) were obtained
Design, construction and characterisation of an iron air battery for automotive propulsion
No full textNovel energy storage technologies are required to further the development of crucial applications to reduce the dependence on fossil fuels. In particular for electric propulsion and for the efficient utilization of intermittent sources of renewable energy. Metal-air-batteries are appealing candidates to develop these type of energy-storage-technologies due to their theoretical energy-density. In particular the iron-air-battery (IAB) with a theoretical energy-density of 764 W h kg-1 , represents a low cost, environmentally friendly alternative. During the 70s, research into the IAB system was performed and a few laboratory prototypes were developed. Unfortunately, the specific energy density and cell potential of these prototypes were far below their theoretical value due to challenges in their engineering design and electrochemistry performance. Recently, the study of IABs has been of special interest to the automotive industry, due to the possibility of rechargeable metal-air batteries for electric vehicles. Furthermore, the new technological advances in nanomaterials since the 70s, and the use of new catalyst materials in combination with innovative laboratory tools for the manufacturing of the electrodes have enabled IAB s to achieve a further level of development.The main research goal of this Ph.D. research has been to determine the electrochemical performance of a novel IAB using novel nanostructured materials reported in the literature and to gain insight of what are the advantages and main challenges of this electrochemical system. The applied methodology included to develop and optimise each one of its components, mainly the negative iron-electrode, and the positive bifunctional-gas diffusion-electrode. The detailed study of the iron-electrode lead to the comparison of various reported active-iron-materials including: carbonyl iron, hematite, goethite, magnetite and iron sulphide as active-materials in hot-pressed-iron electrodes, this research lead to the development of iron-electrodes with capacities as high as 910 m A g-1 Fe using Fe2O3/C, and mean discharge capacities of 650 m A g -1 Fe over 240 hrs of continuous reduction-oxidation cycling at the C/5 rate (254.6 mA g-1 Fe). Research on the air electrode lead to the development of a gas diffusion electrode with a remarkably stability able to cycle up to 3000 cycles continuously and to perform at current densities up to 1000 mA cm-2 before deteriorating. Furthermore, the comparison of Ni-Fe hex-cyanoferrate, palladium and LSFCO perovskite on carbon as bifunctional catalysts and its combination lead to the development of optimised gas diffusion electrodes. In parallel the development as a proof of concept of an IAB stack and a larger scale IAB (200cm2 GDE electrodes) required the engineering design of various IAB prototypes which were manufactured using 3D printing techniques that allowed rapid modifications and improvements before an optimised prototype was sent to be manufactured using traditional computer numerical control machining. The electrochemical testing of these batteries prototypes are as well part of the main results of this research.Finally, the electrochemical performance of a novel iron air battery prototype with an energy density as high as 453 W h kg-1 Fe and a maximum capacity of 814 mA h g -1 Fe when cycled at a current density of 10 mA cm-2 equivalent to 100 mA g-1 Fe, achieving a power density of ca. 75 W kg-1 Fe was achieved.<br/
Inorganic phosphate and coronary perfusion pressure mediate contractile dysfunction during mild ischemia
No full text During mild graded ischemia in perfused rat hearts, we (V.M. Figueredo, R. Brandes, M. W. Weiner, B. M. Massie, and S. A. Camacho. J. Clin. Invest 90: 1794-1802, 1992) previously found a relationship between decreased left ventricular developed pressure (LVDP) and increased Pi, in which intracellular pH, cytosolic Ca2+ concentration ([Ca2+]i), ATP, and free-energy change of ATP hydrolysis were not altered enough to affect contractility. However, the contribution of decreased coronary perfusion pressure (CPP) to decreased LVDP could not be determined. Thus, in the present study, graded hypoxia in perfused rat hearts (95-37.5% O2) was used to increase Pi to similar levels produced during mild ischemia without altering CPP and minimizing changes of other potential mediators of contractile dysfunction. 31P-magnetic resonance spectroscopy and indo 1 fluorescence were used to assess energy metabolites and [Ca2+]i, respectively. The relationship between LVDP and Pi during graded hypoxia was fit to a monoexponential (LVDP = 105 x e-0.04Pi). These data were compared with the relationship of LVDP and Pi during mild ischemia (LVDP = 106 x e-0.08Pi) (V. M. Figueredo, R. Brandes, M. W. Weiner, B. M. Massie, and S. A. Camacho. J. Clin. Invest 90: 1794-1802, 1992). The exponential constant, which describes the effect of Pi on LVDP, was 50% lower during graded hypoxia relative to mild ischemia. This suggests that another mediator, which accounted for approximately 50% of the decrease of LVDP during mild ischemia, was not present during hypoxia. Because CPP decreased during ischemia but not hypoxia, these data suggest that CPP and Pi contribute similarly in mediating contractile dysfunction during mild ischemia. </jats:p
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