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13th Mediterranean Conference on Medical and Biological engineering and Computing 2013, MEDICON 2013

作者： Da Silva, P.J.G. Rosa, B.P. Cagy, M. Infantosi, A.F.C. Biomedical Engineering Program/Coppe Federal University of Rio de Janeiro Rio de Janeiro Brazil

ISBN: (纸本)9783319008455

The coherent average was used for investigating the motion-related VEP (M-VEP). The electroencephalogram (EEG) signals of 29 healthy subjects were acquired during stabilometric protocol with distinct virtual scenes: static (SS) and dynamic (forward, DSF, or backward motion, DSB). The grandaveraged M-VEP for these visual conditions presented N2 peak dominance with higher values for parietal EEG derivation. The DS increased the N2 peak and latency, as well as the N2 - P3 amplitude, in comparison with SS. These components are not sensitive to motion orientation (t-test α = 0.05). However, the running t-test (α = 0.05) showed difference in the DSF - DSB waveforms 600 ms after the DS onset, with an increasing time delay from the occipital to central derivations. These findings suggest that the cognitive, planning and motor processing to maintain balance depends on the virtual scene direction. © Springer International Publishing Switzerland 2014.

关键词： Electroencephalography

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Effects of superimposed electrical stimulation training on vertical jump performance: A comparison study between men and women

Effects of superimposed electrical stimulation training on v...

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13th Mediterranean Conference on Medical and Biological engineering and Computing 2013, MEDICON 2013

作者： Costa, Denise da Conceição da Souza, M.N. Pino, A.V. Biomedical Engineering Program/COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil

ISBN: (纸本)9783319008455

Vertical jump height is a relevant feature in the assessment of muscle power;besides, jumps are essential in sports like volleyball, basketball and gymnastics. Training protocols combining Neuromuscular Electrical Stimulation (NMES) to voluntary contractions are valuable tools to improve jump height, although differences are expected according to gender. This paper aimed to evaluate the effects of a 4-week training protocol superimposing NMES to squats, into the vertical jump height of healthy, non-athlete men and women. Six women and eight men, age between 18 and 35, volunteered the study, being divided into groups according to gender, and subdivided into a group that would receive NMES and the control group. All the volunteers performed 5 series of 10 squats along the four weeks;a series of 10 Counter-Movement Jump and other of 10 Squat Jump were performed before and after the training protocol, in order to evaluate jump improvement. The results indicate that the superimposed training protocol improves men's jump height, although no results have been found for women. © Springer International Publishing Swit zerland 2014.

关键词： Sports

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Response detection in narrow-band EEG using signal-driven non-periodic stimulation

Response detection in narrow-band EEG using signal-driven no...

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13th Mediterranean Conference on Medical and Biological engineering and Computing 2013, MEDICON 2013

作者： Cagy, M. Infantosi, Antonio Fernando Catelli Biomedical Engineering Program/Coppe Federal University of Rio de Janeiro Rio de Janeiro Brazil

ISBN: (纸本)9783319008455

Statistical Objective Response Detection (ORD) Techniques applied to Evoked Potentials usually depend on the effective Number of Degrees of Freedom (NDOF) of spontaneous EEG. Previous works proposed a method for estimating the NDOF of the Evoked Potential Detector (EPD) probability distribution under the null hypothesis of no response, based on the EEG autocorrelation function (ACF) when EEG is modeled as a wide-or narrow-band colored noise. Considering narrow-band EEG, the use of Beta distribution based on NDOF estimates via ACF is able to reflect EPD distribution provided that the stimulation rate is non-uniform. The present work assesses a simple real-time criterion based on FFT for randomizing the inter-trial interval using Monte Carlo simulation for several combinations of EEG bandwidths, central frequencies, numbers of epochs and number of samples per epoch. The results suggest such approach as a valid algorithm to be implemented in the development of specific devices to produce random inter-stimuli intervals. © Springer International Publishing Switzerland 2014.

关键词： Intelligent systems

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Characterization of Acoustical Properties of a Phantom for Soft Tissues (PVCP and Graphite Powder) in the Range 20-45̊C

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Physics Procedia 2015年 70卷 179-182页

作者： G. Cortela N. Benech W.C.A. Pereira C. Negreira Universidad de la República Laboratorio de Acústica Ultrasonora Iguá 4225 Montevideo 11400Uruguay Federal University of Rio de Janeiro Biomedical Engineering Program - COPPE PO Box 68510 21941-972 Rio De Janeiro Brazil

Stability and duration of ultrasonic (US) Phantoms are still a subject of research. We present a study of acoustic and mechanical properties for polyvinyl chloride plastisol (PVCP) with graphite powder (at 2% in weight) used to construct tissue-like phantoms in the temperature range of 20-45C. PVCP is a new material in the field of US phantoms and has longer duration and stability than the conventional organic mimicking materials. Longitudinal US velocity and attenuation were measured at 1 MHz by the standard transmission method. Shear velocity was obtained by 1-D transient elastography. The extreme values for each of the parameters were obtained at 20 C and 45C. They are: 1501.5±0.7 m/s and 1331.8±0.3 m/s for longitudinal US velocity; 0.46±0.03 dB/cm and 0.94±0.09 dB/cm for attenuation; and 8.4±1.2 m/s and 1.7±0.8 m/s for Shear velocity. Specific heat measured with a calorimeter and thermal conductivity measured by the method of hot plates were, respectively, 2.65±0.51 J/(kgC) and 0.091±0.013J/(s°Cm), both at 22 °C. For 2% of graphite powder, the parameter ranges were compatible to biological tissue ones and therefore, the same phantom can simulate different conditions only by changing its temperature. Other graphite percentages are to be tested to simulate parameter values of pathological conditions like nodules, calcification, fibrosis, etc. The phantom did not suffer from dehydration and is easy to be built in several different geometries.

关键词： Polyvinyl chloride plastisol Tissue-mimicking Acoustic parameters Elasticity

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Effect of the ultrasound wave propagation regime in the heat source term of Penne’s bio-heat transfer equation

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Proceedings of Meetings on Acoustics 2016年第1期28卷

作者： Guillermo Cortela Carlos Negreira Wagner C. A. Pereira 1Laboratorio de Acústica Ultrasónica University of the Republic Montevideo Uruguay gcortela@fisica.edu.uy carlosn@fisica.edu.uy 2Biomedical Engineering Program COPPE/Federal University of Rio de Janeiro Brazilwagner@peb.ufrj.br

This work analyses the influence of the ultrasound wave propagation regime on the temperature increase on biological media. Simulated and experimental temperature values from bovine ex-vivo tissue in two different depths, 5 and 40 mm, respectively smaller and bigger than the mean free propagation path (ℓS = 8.52 mm), are obtained. Temperature curves measured during US therapeutic application (High Intensity Therapeutic Ultrasound, HITU, 1 MHz, 1.5 – 2.0 Wcm−2) for 10 min, are compared to simulated ones using the Penne’s bio-heat transfer equation (BHTE) at the same frequency and intensities and using the standard source term (ultrasonic absorption coefficient). At 5 mm, estimated and measured temperature diverge no more than 1%, while at 40 mm, when the scattering starts being not negligible, the simulated temperature is 20% smaller than the measured one. The results indicate that absorption increases when the wave propagation regime changes for depths greater than the ℓS value.

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An interpolation-free and fitting-less sub-sample time-delay estimation algorithm

An interpolation-free and fitting-less sub-sample time-delay...

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International Conference on Health Informatics, ICHI 2013

作者： Teixeira, César A. Ruano, M. Graça Pereira, W.C.A. Centre for Informatics and Systems University of Coimbra Coimbra Portugal University of Algarve Faro Portugal Biomedical Engineering Program - COPPE Federal University of Rio de Janeiro-UFRJ Rio de Janeiro Brazil

ISBN: (纸本)9783319030043

In this paper we propose a new algorithm for sub-sample time-delay estimation between two discrete-time signals. The new algorithm operates just over the discrete-time signals without the need for interpolation or fitting. The proposed method is compared with a method based on spline fitting, and that is referred to outperform other methods over a broader set of conditions (Viola&Walker, 2005). The new approach, besides presenting a low computational cost (70% less), seemed to outperforms the spline approach in situations of high noise levels (typically signal-to noise ratios smaller than 20dB). © 2014, Springer International Publishing Switzerland.

关键词： Interpolation

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Breast tumor classification in ultrasound images using neural networks with improved generalization methods

Breast tumor classification in ultrasound images using neura...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society

作者： S. D de S. Silva M. G. F. Costa W. C. de A. Pereira C. F. F. Costa Filho a graduate student of Amazonas Federal University Manaus AM 69077-000 Brazil the Center for Research and Development in Electronic and Information Technology Federal University of Amazonas Manaus AM 69077-000 Brazil Biomedical Engineering Program/COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil the Center for Research and Development in Electronic and Information Technology Federal University of Amazonas from Technology and Information Center Manaus AM 69077-000 Brazil

ISBN: (纸本)9781424492695

Mammography, scintimammography and ultrasound images have been used to increase the specificity of breast cancer image diagnosis. Concerning breast cancer image diagnosis with ultrasound, some results found in the literature show better performance of morphological features in breast cancer lesion differentiation and that a reduced set of features shows a better performance than a large set of features. In this study we evaluated the performance of neural network classifiers, with different training stop criteria: mean square error, early stop and regularzation. The last two criteria were developed to improve neural network generalization. Different sets of morphological features were used as neural network inputs. Training sets comprised of 22, 8, 7, 6, 5 and 4 features were employed. To select reduced sets of features, a scalar selection technique with correlation was used. The best results obtained for accuracy and area under the ROC curve were 96.98% and 0.98, respectively. The performance obtained with all 22 features is slightly better than the one obtained with a reduced set of features.

关键词： accuracy and area under ROC best results obtained

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Dynamic visual stimulation effects on cortical response EEG desynchronization

Dynamic visual stimulation effects on cortical response EEG ...

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World Congress on Medical Physics and biomedical engineering

作者： Da Silva, P.J.G. Miranda De Sá, A.M.F.L. Infantosi, A.F.C. Biomedical Engineering Program / COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil

ISBN: (纸本)9783642293047

The time evolution of the event related desynchronization/synchronization index (ERD/ERS) was used for investigating the cortical activity effects of stimulating with virtual scenes. Occipital and parietal EEG leads of 29 healthy subjects were acquired during stabilometric test without and with visual stimulation (dynamic - DS;and static - SS virtual scene). Three EEG signal-processing procedures were used to analyze the ERD at the alpha peak frequency during the virtual stimulation, one of them excluding the EEG DS segment before normalization. This procedure decreased ERD index and hence 48.3 to 58.6% of subjects presenting cortical response after changing the virtual stimulation from the static to the dynamic scenes. The Wilcoxon test (α = 0.05) results indicate difference in the cortical response due to the EEG signalprocessing procedures (smaller percentage of ERD after excluding DS). These findings indicate the potentiality of the ERD/ERS assessment in studies of postural control during visual stimulation. © 2013 Springer-Verlag.

关键词： Virtual reality

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Computational simulations of time of flight and attenuation of first arriving signal from healing process of diaphyseal femur fractures.

Computational simulations of time of flight and attenuation ...

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21st International Congress on Acoustics, ICA 2013 - 165th Meeting of the Acoustical Society of America

作者： Rosa, Paulo Tadeu C. Fontes-Pereira, Aldo J. Pereira, Wagner C. COPPE - Biomedical Engineering Program Federal University of Rio de Janeiro Rio de Janeiro 21941-914 Brazil

Quantitative Ultrasound (QUS) has been proposed to evaluate structural conditions from bone tissue in a non-invasive way. These techniques are based on the fact that the ultrasound propagation depends directly of tissues structures, so, they carry information about them. Based on these arguments, the aim of this work was to estimate the time-of-flight (TOF) and attenuation of The first arriving signal (FAS) using computational simulations (Wave2000® CyberLogic, inc., NY, EUA) in an axial transmission model in different kinds of fracture, during the healing process. In this work we used QUS techniques to analyze the fracture healing process. The FAS has been chosen because it does not suffer interference of other waves since it is the first signal to arrive at the receiver. TOF increases immediately after bone fracture. When bone tissue starts to consolidate, TOF decreases and stabilizes with the same value of the intact bone. Attenuation is bigger in oblique and spiculate fracture than transversal ones for the same stage which suggests that attenuation is sensitive to the kind of fracture. Other studies are being conducted to clarify this point. © 2013 Acoustical Society of America.

关键词： Bone

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A brief profile of biomedical engineering education in Latin America

A brief profile of biomedical engineering education in Latin...

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World Congress on Medical Physics and biomedical engineering

作者： Mestas, C.A. Infantosi, A.F.C. Nascimento, L.N. Calil, S.J. Department of Biomedical Engineering School of Electrical and Computer Engineering University of Campinas Campinas Brazil Biomedical Engineering Program COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil

ISBN: (纸本)9783642293047

biomedical engineering has been an important ally to Medicine in providing new technologies for healthcare. Nevertheless, biomedical engineering Education is not provided homogeneously around the world and it may present relevant differences even among neighboring countries. A survey was conduct in Latin America to identify the major characteristics of biomedical engineering Education in that region. In the educational programs on the three academic levels (under-graduation, MSc and PhD) of the responding institutions, there are similarities in several topics present in each academic curriculum and in some research areas. To obtain a more accurate profile of biomedical engineering Education in Latin America, it will be required an even more detailed questionnaire and higher response rates. © 2013 Springer-Verlag.

关键词： biomedical engineering

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