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Pinheiro A.C.,Institute Tecnologia | De Souza M.V.N.,Institute Tecnologia | Tiekink E.R.T.,University of Malaya | Wardell S.M.S.V.,CHEMSOL
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

The mol-ecule of the title compound, C 16H 23N 3O5, is twisted about the chiral C atom, the dihedral angle formed between the amide residues being 79.6 (3)°. The conformation about the imine bond [1.278 (5) Å] is E. In the crystal, O - H⋯O and N - H⋯O hydrogen bonding between the hy-droxy, amine and carbonyl groups leads to the formation of supra-molecular layers, which stack along the c-axis direction. © Pinheiro et al. 2011.


De Souza M.V.N.,Institute Tecnologia | Pinheiro A.C.,Institute Tecnologia | Tiekink E.R.T.,University of Malaya | Wardell S.M.S.V.,CHEMSOL
Acta Crystallographica Section E: Structure Reports Online | Year: 2010

The shape of the title compound, C19H21N 3O6, is curved with the conformation about the imine bond [1.291 (3) Å] being E. While the hy-droxy-substituted benzene ring is almost coplanar with the hydrazinyl residue [N - N - C - C = 177.31 (18)°], an observation correlated with an intra-molecular O - H⋯N hydrogen bond leading to an S(6) ring, the remaining residues exhibit significant twists. The carbonyl residues are directed away from each other as are the amines. This allows for the formation of O - H⋯O and N - H⋯O hydrogen bonds in the crystal, which lead to two-dimensional supra-molecular arrays in the ac plane. Additional stabilization to the layers is afforded by C - H⋯π inter-actions.


Sicre E.E.,Institute Tecnologia | Duchowicz R.,National University of La Plata
Optics and Lasers in Engineering | Year: 2014

Abstract In this work, an interrogation method for FBG sensors is presented based on a wavelength-to-time transformation procedure. The proposed scheme uses an externally modulated broadband source, an optical circulator and three Bragg gratings fixed in three different fiber branches, one acting as sensor (FBGS) and others two (FBG1 and FBG2) acting as wavelength calibration devices. Spectral positions of the reflectivity maximum of FBG1,2 are slightly different and fixed while FBGS spectral position lies in the reflection spectral range of FBG1,2. Moreover, an optical time delay between the reflections of both calibration gratings is introduced including a path length greater in one of the branches. Reflections from both gratings are added by employing a 50/50 coupler. By this set-up, a phase sensible detection technique is generated allowing to reach a sensitivity of up to 660 /nm in the performed experiments. A theoretical analysis of the device performance was carried out showing good agreement with the experimental results. This system combines low cost and high flexibility to be customized in a particular application. © 2013 Elsevier Ltd.


Bender J.P.,URI Integrated Regional University Brazil | Feitein M.,URI Integrated Regional University Brazil | Mazutti M.A.,URI Integrated Regional University Brazil | Franceschi E.,Institute Tecnologia | And 2 more authors.
Journal of Chemical Thermodynamics | Year: 2010

Recently, production of biocompatible and biodegradable polymer microparticles has been a matter of growing interest in pharmaceutical and food areas such as drug or active compounds delivery. To conduct production of microparticles, polymeric particle coating, impregnation of active compounds in polymeric films, the knowledge of phase behaviour involving the biodegradable polymer in supercritical carbon dioxide in the presence of a modifier may be needed to allow developing new industrial applications. In this sense, the aim of this work was to investigate the phase behaviour of the ternary system formed by the biodegradable polymer poly(ε-caprolactone) in (carbon dioxide + dichloromethane). Experimental phase transition (bubble and cloud point) values were obtained by applying the static-synthetic method using a variable-volume view cell over the temperature range of (303 to 343) K and pressures up to 21 MPa, in the CO2 overall composition range of (25-46) wt%, while polymer concentrations studied were (1, 3, 5, and 7) wt%. For the system investigated, depending on the polymer concentration, vapour-liquid, liquid-liquid, and vapour-liquid-liquid phase transitions were verified. © 2009 Elsevier Ltd. All rights reserved.


Justino M.C.,Institute Tecnologia | Justino M.C.,Polytechnic Institute of Setúbal | Parente M.R.,Institute Tecnologia | Boneca I.G.,Institute Pasteur Paris | And 2 more authors.
FEBS Journal | Year: 2014

Helicobacter pylori is a pathogen that infects the gastric mucosa of a large percentage of the human population worldwide, and predisposes to peptic ulceration and gastric cancer. Persistent colonization of humans by H. pylori triggers an inflammatory response that leads to the production of reactive nitrogen species. However, the mechanisms of H. pylori defence against nitrosative stress remain largely unknown. In this study, we show that the NADH-flavin oxidoreductase FrxA of H. pylori, besides metabolizing nitrofurans and metronidazole, has S-nitrosoglutathione reductase activity. In agreement with this, inactivation of the FrxA-encoding gene resulted in a strain that was more sensitive to S-nitrosoglutathione. FrxA was also shown to contribute to the proliferation of H. pylori in macrophages, which are key phagocytic cells of the mammalian innate immune system. Moreover, FrxA was shown to support the virulence of the pathogen upon mouse infection. Altogether, we provide evidence for a new function of FrxA that contributes to the successful chronic colonization ability that characterizes H. pylori. © 2014 FEBS.


Garayalde D.A.,Institute Tecnologia | Negri P.,Institute Tecnologia | Negri P.,CONICET
2014 IEEE Biennial Congress of Argentina, ARGENCON 2014 | Year: 2014

Machine vision systems comprise a technology whose development has grown exponentially in recent years. These technologies not only make an essential tool for certain applications, but also enable the substitution of multiple mono-variable sensors (used in process automation) for a single multi-variable sensor adquisition system. In this paper the actual implementation of an inverted pendulum is presented. The control loop is based on artificial vision for the determination of position and the application of a Kalman Filter for the estimation of complete system state. This document describes the model of the system, its stochastic characterization, implementation of Kalman Filter and vision system considerations aimed at improving its robustness. Simulations and tests are presented concluding with the comparative analysis of image-based measurement vs encoders based measurement. © 2014 IEEE.


Negri P.,CONICET | Negri P.,Institute Tecnologia | Lotito P.,CONICET | Lotito P.,Campus Universitario
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

This work gives the guidelines to develop a pedestrian detection system using a feature space based on colored level lines, called Movement Feature Space (MFS). Besides detecting the movement in the scene, this feature space defines the descriptors used by the classifiers to identify pedestrians. The multi-channel level lines approach has been tested on the HSV color space, which improves the one-channel (gray scale) level lines calculation. Locations hypotheses of pedestrian are performed by a cascade of boosted classifiers. The validation of these regions of interest is carry out by a Support Vector Machine classifier. Results give more than 78.5 % of good detections on urban video sequences. © 2012 Springer-Verlag.


Lazarte A.I.,Autoridad Regulatoria Nuclear | Ferreri J.C.,Institute Tecnologia
Annals of Nuclear Energy | Year: 2014

In the analysis of the nuclear safety of complex nuclear systems, almost one-dimensional system thermal-hydraulics codes will be used perhaps for a couple of decades from now. Computational Fluid Dynamics (CFD) tools are accepted at present to be a support of such analyses and they are used coupled to systems codes or as separate analysis tools for isolated components with boundary conditions obtained from systems codes. The restricted acceptance of "pure" CFD codes is due to many reasons but two of them are relevant, namely (a) the apparent lack of CFD grade experimental data and (b) the need for a complete verification and validation (V&V) and the uncertainty quantification for the codes currently available. There is plenty of experimental data related to integral test facilities (ITFs) that constitute macroscopic systems behavior information and a consolidated data base for such purposes. Despite of this, additional verification cases may be added to the above mentioned consolidated data. In the present paper, flow oscillations in parallel channel configurations with system codes are studied in diverse configurations. Different models, calculation options and, in particular, in-phase or out-of-phase oscillations were studied, both in heated and cooled parallel channels. The emphasis is on the effects of concentrated irreversible pressure losses coefficients at the inlet and at the outlet of the channels. In the case of cooled steam generator channels, the results of the Semiscale Integral Test Facility operating in natural circulation conditions are revisited. The results presented in this paper, show how a validation case lead to find a not still reported (in the Authors knowledge) verification case. The problem is related to twin-parallel-boiling and condensing, inverted U-tubes channels and connected through common plena. This is, of course, a problem that deserved many tens of papers in the last four decades. Flow splitting without reversal was computationally found and to explain this behavior a theoretical model limited in scope was developed that was a posteriori verified using a particular systems code (RELAP5) commonly applied to perform safety analyses of nuclear power plants. The rationale followed, the theoretical analysis performed and the confirmatory computational results found are summarized in this paper. © 2014 Elsevier Ltd. All rights reserved.


Negri P.,CONICET | Negri P.,Institute Tecnologia | Goussies N.,CONICET | Lotito P.,CONICET | Lotito P.,Campus Universitario
Pattern Recognition | Year: 2014

This work aims at detecting pedestrians in surveillance video sequences. A pre-processing step detects motion regions on the image using a scene background model based on level lines, which generates a Movement Feature Space, and a family of oriented histogram descriptors. A cascade of boosted classifiers generates pedestrian hypotheses using this feature space. Then, a linear Support Vector Machine validates the hypotheses that are likeliest to contain a person. The combination of the three detection phases reduces false positives, preserving the majority of pedestrians. The system tests conducted in our dataset, which contain low-resolution pedestrians, achieved a maximum performance of 25.5% miss rate with a rate of 10-1 false positives per image. This value is comparable to the best detection values for this kind of images. In addition, the processing time is between 2 and 6 fps on 640×480 pixel captures. This is therefore a fast and reliable pedestrian detector. © 2013 Elsevier Ltd. All rights reserved.


Negri P.,CONICET | Negri P.,Institute Tecnologia
IET Image Processing | Year: 2014

This study aims to estimate the traffic load at street intersections obtaining the circulating vehicle number through image processing and pattern recognition. The algorithm detects moving objects in a street view by using level lines and generates a new feature space called movement feature space (MFS). The MFS generates primitives as segments and corners to match vehicle model generating hypotheses. The MFS is also grouped in a histogram configuration called histograms of oriented level lines (HO2 L). This work uses HO2 L features to validate vehicle hypotheses comparing the performance of different classifiers: linear support vector machine (SVM), non-linear SVM, neural networks and boosting. On average, successful detection rate is of 86% with 10-1 false positives per image for highly occluded images. © The Institution of Engineering and Technology 2014.

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