Military Institute of Engineering of Rio de Janeiro

Rio de Janeiro, Brazil

Military Institute of Engineering of Rio de Janeiro

Rio de Janeiro, Brazil
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Mangas I.,University Miguel Hernández | Mangas I.,Military Institute of Engineering of Rio de Janeiro | Estevez J.,University Miguel Hernández | Vilanova E.,University Miguel Hernández
Chemico-Biological Interactions | Year: 2016

OPs are a large diverse class of chemicals used for several purposes (pesticides, warfare agents, flame retardants, etc.). They can cause several neurotoxic disorders: acute cholinergic toxicity, organophosphorus-induced delayed neuropathy, long-term neurobehavioral and neuropsychological symptoms, and potentiation of neuropathy. Some of these syndromes cannot be fully understood with known molecular targets. Many enzyme systems have the potential to interact with OPs. Since the discovery of neuropathy target esterase (NTE), the esterases that hydrolyze phenyl valerate (PVases) have been of interest. PVase components are analyzed in chicken tissue, the animal model used for testing OP-delayed neurotoxicity. Three enzymatic components have been discriminated in serum, and three in a soluble fraction of peripheral nerve, three in a soluble fraction of brain, and four in a membrane fraction of brain have been established according to inhibitory kinetic properties combined with several inhibitors. The criteria and strategies to differentiate these enzymatic components are shown. In the brain soluble fraction three enzymatic components, namely Eα, Eβ and Eγ, were found. Initial interest focused on Eα activity (highly sensitive to paraoxon and spontaneously reactivated, mipafox and resistant to PMSF). By protein separation methods, a subfraction enriched in Eα activity was obtained and 259 proteins were identified by Tandem Mass Spectrometry. Only one had the criteria for being serine-esterase identified as butyrylcholinesterase, which stresses the relationship between cholinesterases and PVases. The identification and characterization of the whole group of PVases targets of OPs (besides AChE, BuChE and NTE) is necessary to clarify the importance of these other targets in OPs neurotoxicity or on detoxication pathways. A systematic strategy has proven useful for the molecular identification of one enzymatic component, which can be applied to identify them all. © 2016

Figueroa-Villar J.D.,Military Institute of Engineering of Rio de Janeiro
RSC Advances | Year: 2017

This article describes the synthesis of three novel compounds for the treatment of Alzheimer's disease (AD). The compounds were formed by the reaction of 3-methoxy-2-hydroxybenzaldehyde (1) with dimedone (2) using water as solvent at room temperature. Subsequently, Na2S or NaCl was added under reflux to obtain (R)-9-mercapto-5-methoxy-3,3-dimethyl-3,4-dihydro-2H-xanthen-1(9H)-one (5) and 9-chloro-3,4-dihydro-5-methoxy-3,3-dimethyl-2H-xanthen-1(9H)-one (6), respectively. The final reaction proceeded under reflux with water only to obtain 3,4-dihydro-9-hydroxy-5-methoxy-3,3-dimethyl-2H-xanthen-1(9H)-one (7). Compounds 5, 6 and 7 were selected due to their structural similarities to tacrine, which is one of the most effective AChE inhibitors for AD. The compounds were studied by nuclear magnetic resonance (NMR) to assign all chemical shifts and determine their three-dimensional structures. A parallel molecular modeling study was conducted to confirm the NMR results and obtain the energy, dipole moment, area, polar surface area (PSA) and volume of each compound. The PSA values indicated that the new compounds should be able to cross the blood-brain barrier. Compounds 5, 6 and 7 were then tested as inhibitors of human acetylcholinesterase (HuAChe) using docking experiments, and in vitro tests of the compounds as HuAChe inhibitors were performed using the Fig-NMR method with tacrine as a reference. The results confirmed that the new compounds are effective agents for the treatment of AD. Toxicity tests carried out using mice indicated very low toxicity. The findings suggest that the new compounds are better agents than tacrine for the treatment of AD. © 2017 The Royal Society of Chemistry.

De Biasi R.S.,Military Institute of Engineering of Rio de Janeiro | Grillo M.L.N.,State University of Rio de Janeiro
Ceramics International | Year: 2013

Electron magnetic resonance (EMR) line widths of Mn2+ in CdO were measured in samples doped with small concentrations (up to 1.0 mol%) of Mn. The line width of one of the lines, which corresponds to the1/2 1/2>↔|-1/2 1/2> transition, was found to change in a predictable way with Mn concentration, according to the theoretical equation ΔH pp=2.05+370f(1-f)42, where ΔHpp is the line width in mT and f is the Mn concentration in mol%. The experimental results show that the technique can be used to measure, rapidly and nondestructively, small concentrations of Mn in commercial CdO. © 2012 Elsevier Ltd and Techna Group S.r.l.

Ellmauthaler A.,Federal University of Rio de Janeiro | Pagliari C.L.,Military Institute of Engineering of Rio de Janeiro | Da Silva E.A.B.,Federal University of Rio de Janeiro
IEEE Transactions on Image Processing | Year: 2013

Multiscale transforms are among the most popular techniques in the field of pixel-level image fusion. However, the fusion performance of these methods often deteriorates for images derived from different sensor modalities. In this paper, we demonstrate that for such images, results can be improved using a novel undecimated wavelet transform (UWT)-based fusion scheme, which splits the image decomposition process into two successive filtering operations using spectral factorization of the analysis filters. The actual fusion takes place after convolution with the first filter pair. Its significantly smaller support size leads to the minimization of the unwanted spreading of coefficient values around overlapping image singularities. This usually complicates the feature selection process and may lead to the introduction of reconstruction errors in the fused image. Moreover, we will show that the nonsubsampled nature of the UWT allows the design of nonorthogonal filter banks, which are more robust to artifacts introduced during fusion, additionally improving the obtained results. The combination of these techniques leads to a fusion framework, which provides clear advantages over traditional multiscale fusion approaches, independent of the underlying fusion rule, and reduces unwanted side effects such as ringing artifacts in the fused reconstruction. © 1992-2012 IEEE.

Borges Jr. I.,Military Institute of Engineering of Rio de Janeiro
Journal of Molecular Modeling | Year: 2014

Singlet, triplet and ionized states of the energetic molecule 1,1-diamino-2,2-dinitroethylene, known as FOX-7 or DADNE, were investigated using the symmetry-adapted-cluster configuration interaction (SAC-CI) ab initio wave function. The 20 computed singlet transitions, with 2 exceptions, were bright. The most intense singlet transitions were of the nO→π type-typical of molecules having nitro groups. Fast intersystem crossing (ISC) from the 11A, 21A and 81A bright singlet transitions is possible. Other feasible ISC processes are discussed. The computed singlet and ionization spectra have similar features when compared to nitramide and N,N-dimethylnitramine molecules, which have only a nitro group. The ionization energies of the first 20 states have differences in comparison with Koopmans' energy values that can reach 3 eV. Moreover, the character of the first ionized states, dominated by single ionizations, is not the same when compared with the character resulting from application of Koopmans' theorem. © 2014 Springer-Verlag.

Dias M.H.C.,Military Institute of Engineering of Rio de Janeiro | De Assis M.S.,Federal University of Fluminense
IEEE Transactions on Antennas and Propagation | Year: 2011

A vegetation path loss model was derived from measurements performed in a downtown park in Rio de Janeiro city, from 0.9 to 1.8 GHz. The resulting equation followed the general formulation in ITU-R Recommendation P.833. A comparative analysis was carried out with other empirical models, assessing statistical adherence to the available data. Coherent results were observed. © 2006 IEEE.

Caldeira A.B.,Military Institute of Engineering of Rio de Janeiro
Numerical Heat Transfer; Part A: Applications | Year: 2016

Ignition and combustion of an infinite linear array of gaseous fuel pockets in a stagnant oxidizing environment under the microgravity condition is studied by a numerical approach. The combustion process is considered isobaric and the fluid motion is induced by density gradients due to the heat and mass transfer processes. A simple finite chemical reaction mechanism and the ideal gas equation of state are considered. The thermophysical properties, except density, are assumed constant. The Finite Volume Method is used with a hybrid non-staggered grid in a generalized system of coordinates. The SIMPLEC algorithm solves the modified pressure–velocity coupling. The Damköhler number effects on flame dynamics and on the fuel consumption are analyzed. Three stages in the burning processes: the induction time, the flame propagation and the diffusive burning are identified. The merging processes of the fuel pockets and of the flames are depicted. 2016 Copyright © Taylor & Francis Group, LLC

Elias C.N.,Military Institute of Engineering of Rio de Janeiro | Meirelles L.,Gothenburg University
Expert Review of Medical Devices | Year: 2010

In the beginning of implantology, the procedures adopted for treating patients were performed in two surgical phases with an interval of 3-6 months. Nowadays, it is possible to insert and load a dental implant in the same surgical procedure. This change is due to several factors, such as improvement of surgical technique, modifications of the implant design, increased quality of implant manufacturing, development of the surgical instruments quality, careful patient screening and adequate treatment of the implant surface. The clinical results show that adequate treatment of surfaces is crucial for reducing healing time and treating at-risk patients. The surface properties of dental implants can be significantly improved at the manufacturing stage, affecting cells activity during the healing phase that will ultimately determine the host tissue response, a fundamental requirement for clinical success. This review focuses on different types of dental implant surfaces and the influence of surface characteristics on osseointegration. © 2010 Expert Reviews Ltd.

Vaiss V.S.,Federal University of Juiz de fora | Borges Jr. I.,Military Institute of Engineering of Rio de Janeiro | Leitao A.A.,Federal University of Juiz de fora
Journal of Physical Chemistry C | Year: 2011

Density Functional Theory (DFT) calculations with periodic boundary conditions were used to investigate a degradation reaction mechanism of the Sarin molecule (isopropyl methylphosphonofluoridate, C 4H 10FO 2P) using the layered hydroxide brucite (Mg(OH) 2). We computed the adsorption of Sarin on brucite including the infrared vibrational spectrum of gas and adsorbed Sarin, reaction paths, activation energies, and the Gibbs free energy differences (ΔG). The isopropyl methylphos- phonate molecule and the Mg(OH) 2-xF x compound are the global reaction products. The entire process has ΔG = -19.7 kcal/mol. Two intermediates and two transition states were found. The two transition states correspond to a hydroxyl anion motion toward the phosphorus atom and to a fluoride moving toward the hydroxyl vacant position. From the converged structures, we propose four elementary reactions for the global process. The activation barrier for the rate-limiting step indicates that the degradation reaction of Sarin using brucite is slow. The results of the Sarin deactivation process on brucite show the potential of a layered hydroxide to degrade organophosphorus compounds. © 2011 American Chemical Society.

Guimaraes A.,Military Institute of Engineering of Rio de Janeiro | Ait-El-Fquih B.,Orange Group | Desbouvries F.,Orange Group
IEEE Transactions on Wireless Communications | Year: 2010

We introduce a new sequential importance sampling (SIS) algorithm which propagates in time a Monte Carlo approximation of the posterior fixed-lag smoothing distribution of the symbols under doubly-selective channels. We perform an exact evaluation of the optimal importance distribution, at a reduced computational cost when compared to other optimal solutions proposed for the same state-space model. The method is applied as a soft input-soft output (SISO) blind equalizer in a turbo receiver framework and simulation results are obtained to show its outstanding BER performance. © 2010 IEEE.

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