Aplicação do sistema de biosusceptometria AC para monitoramento de nanopartículas magnéticas na circulação sanguínea

Pós-graduação em Biologia Geral e Aplicada - IBB

Avaliação da atividade eletromecânica uterina em ratas por biosusceptometria AC e eletromiografia

Pós-graduação em Biologia Geral e Aplicada - IBB

A Aprendizagem Cooperativa (AC) como prática educativa ambiental: contribuições para a ampliação do meio ambiente

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dispositivo de microdescargas em gases na pressão atmosférica

This work describes the development of an electro-mechanical micro-discharges device operating at ambient condition of pressure and temperature, capable to produce plasma jets for surface finishing. The discharges are produced through a needle shape electrode hollow cathode type by which flows the helium gas. The voltage applied on the electrode is provided for an AC/AC switching voltage converter of full-bridge topology. The converter is energized by a power line of 110/220 VAC, 60 Hz and gives a 1000 V peak-to-peak from 5 kHz to 40 kHz square waveform output. The output frequency is defined by a control signal provided by an external signal generator. The equipment setup includes output acquisition of voltage and current and a photo-detector for photo-electrical measurements, which allows an optical characterization of the plasma jet

A Comparison of Induction Motor Starting Methods Being Powered by a Diesel-Generator Set

Starting induction motors on isolated or weak systems is a highly dynamic process that can cause motor and load damage as well as electrical network fluctuations. Mechanical damage is associated with the high starting current drawn by a ramping induction motor. In order to compensate the load increase, the voltage of the electrical system decreases. Different starting methods can be applied to the electrical system to reduce these and other starting method issues. The purpose of this thesis is to build accurate and usable simulation models that can aid the designer in making the choice of an appropriate motor starting method. The specific case addressed is the situation where a diesel-generator set is used as the electrical supplied source to the induction motor. The most commonly used starting methods equivalent models are simulated and compared to each other. The main contributions of this thesis is that motor dynamic impedance is continuously calculated and fed back to the generator model to simulate the coupling of the electrical system. The comparative analysis given by the simulations has shown reasonably similar characteristics to other comparative studies. The diesel-generator and induction motor simulations have shown good results, and can adequately demonstrate the dynamics for testing and comparing the starting methods. Further work is suggested to refine the equivalent impedance presented in this thesis.

SimSight: A Virtual Machine Based Dynamic Call Graph Generator

One problem with using component-based software development approach is that once software modules are reused over generations of products, they form legacy structures that can be challenging to understand, making validating these systems difficult. Therefore, tools and methodologies that enable engineers to see interactions of these software modules will enhance their ability to make these software systems more dependable. To address this need, we propose SimSight, a framework to capture dynamic call graphs in Simics, a widely adopted commercial full-system simulator. Simics is a software system that simulates complete computer systems. Thus, it performs nearly identical tasks to a real system but at a much lower speed while providing greater execution observability. We have implemented SimSight to generate dynamic call graphs of statically and dynamically linked functions in x86/Linux environment. A case study illustrates how we can use SimSight to identify sources of software errors. We then evaluate its performance using 12 integer programs from SPEC CPU2006 benchmark suite.

Dispositivo de microdescargas em gases na pressão atmosférica

This work describes the development of an electro-mechanical micro-discharges device operating at ambient condition of pressure and temperature, capable to produce plasma jets for surface finishing. The discharges are produced through a needle shape electrode hollow cathode type by which flows the helium gas. The voltage applied on the electrode is provided for an AC/AC switching voltage converter of full-bridge topology. The converter is energized by a power line of 110/220 VAC, 60 Hz and gives a 1000 V peak-to-peak from 5 kHz to 40 kHz square waveform output. The output frequency is defined by a control signal provided by an external signal generator. The equipment setup includes output acquisition of voltage and current and a photo-detector for photo-electrical measurements, which allows an optical characterization of the plasma jet

Immobilization of cholesterol oxidase in LbL films and detection of cholesterol using ac measurements

The preserved activity of immobilized biomolecules in layer-by-layer (LbL) films can be exploited in various applications. including biosensing. In this study, cholesterol oxidase (COX) layers were alternated with layers of poly(allylamine hydrochloride) (PAH) in LbL films whose morphology was investigated with atomic force microscopy (AFM). The adsorption kinetics of COX layers comprised two regimes, a fast, first-order kinetics process followed by a slow process fitted with a Johnson-Mehl-Avrami (JMA) function. with exponent similar to 2 characteristic of aggregates growing as disks. The concept based on the use of sensor arrays to increase sensitivity, widely employed in electronic tongues, was extended to biosensing with impedance spectroscopy measurements. Using three sensing units, made of LbL films of PAH/COX and PAHIPVS (polyvinyl sulfonic acid) and a bare gold interdigitated electrode, we were able to detect cholesterol in aqueous solutions down to the 10(-6) M level. This high sensitivity is attributed to the molecular-recognition interaction between COX and cholesterol, and opens the way for clinical tests to be made with low cost. fast experimental procedures. (C) 2008 Published by Elsevier B.V.

Experimental Platform for Controlled Faults on Synchronous Generator Armature Windings

An experimental platform that allows application of internal faults on the armature windings of a specially modified synchronous generator in a controlled environment is described. It allows recording and studying current and voltage waveforms of internal fault conditions that may occur in a synchronous generator. Thus, traditional and new protection functions can be tested by using real data, and the transient response of the machine due to internal faults can be analyzed more closely. The hardware-software platform is described in detail, as well as all its control functions. The results can contribute significantly in new protection developments, as well as for educational purposes.

Pressure Dependence of N-15 Chemical Shifts in Model Peptides Ac-Gly-Gly-X-Ala-NH2

High pressure NMR spectroscopy has developed into an important tool for studying conformational equilibria of proteins in solution. We have studied the amide proton and nitrogen chemical shifts of the 20 canonical amino acids X in the random-coil model peptide Ac-Gly-Gly-X-Ala-NH2, in a pressure range from 0.1 to 200 MPa, at a proton resonance frequency of 800 MHz. The obtained data allowed the determination of first and second order pressure coefficients with high accuracy at 283 K and pH 6.7. The mean first and second order pressure coefficients <B-1(15N)> and <B-2(15N)> for nitrogen are 2.91 ppm/GPa and -2.32 ppm/GPa(2), respectively. The corresponding values <B-1(1H)> and <B-2(1H)> for the amide protons are 0.52 ppm/GPa and -0.41 ppm/GPa(2). Residual dependent (1)J(1H15N)-coupling constants are shown.

Design of a Comb Generator for High Capacity Coherent-WDM Systems

This paper presents a theoretical model developed for estimating the power, the optical signal to noise ratio and the number of generated carriers in a comb generator, having as a reference the minimum optical signal do noise ratio at the receiver input, for a given fiber link. Based on the recirculating frequency shifting technique, the generator relies on the use of coherent and orthogonal multi-carriers (Coherent-WDM) that makes use of a single laser source (seed) for feeding high capacity (above 100 Gb/s) systems. The theoretical model has been validated by an experimental demonstration, where 23 comb lines with an optical signal to noise ratio ranging from 25 to 33 dB, in a spectral window of similar to 3.5 nm, are obtained.

The generator coordinate method in the unrestricted Hartree-Fock formalism

The generator coordinate method was implemented in the unrestricted Hartree-Fock formalism. Weight functions were built from Gaussian generator functions for 1s, 2s, and 2p orbitals of carbon and oxygen atoms. These weight functions show a similar behavior to those found in the generator coordinate restricted Hartree-Fock method, i.e., they are smooth, continuous, and tend to zero in the limits of integration. Moreover, the weight functions obtained are different for spin-up and spin-down electrons what is a result from spin polarization. (C) 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012

In vitro cytotoxicity of Selol-loaded magnetic nanocapsules against neoplastic cell lines under AC magnetic field activation

The goals of this study are to evaluate in vitro compatibility of magnetic nanomaterials and their therapeutic potential against cancer cells. Highly stable ionic magnetic fluid sample (maghemite, gamma-Fe2O3) and Selol were incorporated into polymeric nanocapsules by nanoprecipitation method. The cytotoxic effect of Selol-loaded magnetic nanocapsules was assessed on murine melanoma (B16-F10) and oral squamous cell carcinoma (OSCC) cell lines following AC magnetic field application. The influence of different nanocapsules on cell viability was investigated by colorimetric MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. In the absence of AC magnetic field Selol-loaded magnetic nanocapsules, containing 100 mu g/mL Selol plus 5 x 10(12) particle/mL, showed antitumoral activity of about 50% on B16-F10 melanoma cells while OSCC carcinoma cells demonstrated drug resistance at all concentrations of Selol and magnetic fluid (range of 100-500 mu g/mL Selol and 5 x 10(12) -2.5 x 10(13) particle/mL). On the other hand, under AC applied fields (1 MHz and 40 Oe amplitude) B16-F10 cell viability was reduced down to 40.5% (+/- 3.33) at the highest concentration of nanoencapsulated Selol. The major effect, however, was observed on OSCC cells since the cell viability drops down to about 33.3% (+/- 0.38) under application of AC magnetic field. These findings clearly indicate that the Selol-loaded magnetic nanocapsules present different toxic effects on neoplastic cell lines. Further, the cytotoxic effect was maximized under AC magnetic field application on OSCC, which emphasizes the effectiveness of the magnetohyperthermia approach. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3680541]