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14th Annual International Conference of the IEEE engineering in Medicine and Biology Society, EMBS 1992

作者： Klemt, Agela Infantosi, Antonio F. C. Biomedical Engineering Program COPPE Federal University of Rio de Janeiro P.O. Box 68510 Rio de Janeiro RJ21945 Brazil

ISBN: (纸本)0780307852

For the teaching of medicine and dentistry, a system for the development of 3D computer models of the human skull anatomy has been developed, together with a graphics interface for its presentation on screen. The task was implemented on a 386 IBM-PC compatible computer and the model is defined semi-automatically by image processing of a set of Computerized Tomography (CT) slices. The 3D image creation then took, in the worst case, about 110 seconds for each viewing angle. The reconstrnction of the skull was successful and it is therefore expected that the system can readily be applied. © 1992 IEEE.

关键词： Computerized tomography

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Ultrasonic focused pulse-echo method for determination of propagation velocity and layer thickness of multilayered media 14

Ultrasonic focused pulse-echo method for determination of pr...

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14th Annual International Conference of the IEEE engineering in Medicine and Biology Society, EMBS 1992

作者： Pereira, Wagner Coelho A. MacHado, João Carlos Biomedical Engineering Program - COPPE Federal University of Rio de Janeiro P.O. Box 68510 Rio de Janeiro RJ21945 Brazil

ISBN: (纸本)0780307852

Ultrasonic medical images is well established as an important diagnostic tool nowadays. Quantitative ultrasonic images, nevertheless, have not reached a clinical use. The cause of this are the peculiar propagation of ultrasonic waves in the biological tissues. This paper presents a: pulse-echo technique to estimate thickness and ultrasound wave velocity in multilayered media. Results of 8 experiments with an aluminum cylinder (thickness: 60 mm, diameter: 120 mm) phantom are presented and discussed. © 1992 IEEE.

关键词： Ultrasonic waves

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An estimator of focal position based on geometric acoustics

An estimator of focal position based on geometric acoustics

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1992 Ultrasonics Symposium

作者： Pereira, Wagner Coelho A. Simpson, David M. Machado, João C. Biomedical Engineering Program - COPPE Federal University of Rio de Janeiro P.O. Box 68510 Rio de Janeiro RJ21945-970 Brazil

ISBN: (纸本)0780305620

In order to characterize ultrasonic (US) transducers, several aspects may be studied, such as the shape of the beam in space, the US intensity along the central axis and the US intensity parallel to the face of the transducer. With focused beams, a focal region is usually defined. The need for a unique point in space to represent the focus may arise in theoretical models (for example, in geometrical acoustics). In this paper we present a least mean square method to estimate the focal position of US beams in two dimensions (2D) and some simulated and experimental results. © 1992 IEEE.

关键词： Transducers

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Topographic Mapping The Visual Evoked Potential After Source Derivation

Topographic Mapping The Visual Evoked Potential After Source...

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

作者： S.D.V. Carreho-Rimaudo A.F.C. Infantosi COPPE/UFRJ Biomedical Engineering Program COPPE/UFRJ Rio de Janeiro Brazil

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Basic considerations of ultrasonic air-bubble detectors for blood extracorporeal circulation 14

Basic considerations of ultrasonic air-bubble detectors for ...

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14th Annual International Conference of the IEEE engineering in Medicine and Biology Society, EMBS 1992

作者： Da Costa, Luiz Eduardo G. MacHado, João C. Biomedical Engineering Program - COPPE Federal University of Rio de Janeiro P.O. BOX 68510 Rio de Janeiro R.J.21945 Brazil

ISBN: (纸本)0780307852

This work presents an analysis about the limitation of ultrasonic air-bubble detectors based on the measurement of the wave attenuation caused by the presence of air-bubbles in the blood circuit. Considering as a lower limit the amount of 0.5 ml of air in 1 liter of blood for a blood flow rate of 250 ml/min then it is shown that for ultrasonic frequencies of 50 kHz, 100 kHz, 1 MHz and 5 MHz the detectors may fail if the air-bubble diameter exceeds 110, 74, 44 and 38 μm, respectively. © 1992 IEEE.

关键词： Blood

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12th Mediterranean Conference on Medical and Biological engineering and Computing, MEDICON 2010

作者： Da-Silva, P.J.G. Infantosi, A.F.C. Nadal, J. Biomedical Engineering Program COPPE Federal University of Rio de Janeiro P. O. Box 68.510 21941-972 - Rio de Janeiro - RJ Brazil

ISBN: (纸本)9783642130380

In the present work, the Event-Related Synchronization and Desynchronization (ERD/ERS) index was used for evaluating the cortical response to dynamic visual stimulation in an postural control protocol. EEG signals (O1, P3, P4 and O2 derivations) of 33 healthy subjects were acquired during stabilometric test. The trials were conducted with the subject observing a white wall (WW) and a virtual scene on static (SS) and dynamic (DS) conditions. The power spectra estimates were compared using the Spectral F-Test (SFT, α = 0.05 and Bonferroni correction) and the ERD/ERS index. The SFT results indicate no difference between the EEG power contribution of WW and SS, and decreased power within alpha band during DS for all derivations. The ERD/ERS index allowed successfully detecting above 83% of the desynchronization within the alpha band during dynamic stimulation. Moreover, it also promotes postural instability. This finding indicates the potentiality of the ERD/ERS technique in studies of postural control assessed by dynamic visual stimulation. © 2010 International Federation for Medical and Biological engineering.

关键词： Virtual reality

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Iterative optimization algorithm - An alternative clustering tool for biological analysis using flow cytometry data

Iterative optimization algorithm - An alternative clustering...

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2012 Pan American Health Care Exchanges, PAHCE 2012 - Conference, Workshops, and Exhibits. Cooperation / Linkages: An Independent Forum for Patient Aare and Technology Support

作者： Alves, E.T.A. Frucht, L.C. Souza, M.N. Nóbrega, A.F.A. Biomedical Engineering Program COPPE/UFRJ Rio de Janeiro RJ Brazil Microbiology Institute CCS/UFRJ Rio de Janeiro RJ Brazil Inovecare Company Brazil

ISBN: (纸本)9781467311328

This work concerns a program (EFlow) that has been developed to assist experts in clustering flow cytometry multivariate data. EFlow aims to reduce subjectivity but keeping the expert's control over the analysis. In the present paper we will focus on the use of the iterative optimization algorithm. This algorithm is a hill-climbing unsupervised procedure that in general guarantees good local but not global optimization. A comparison between clustering processes achieved by an expert in flow cytometry and by EFlow was performed in a data related to bone marrow cells stained for the surface expression of molecules (B220, IgM and CD23) that characterize the B cell lineage. This data set is considered to present a medium difficult and had 63780 cells with 7 channels or dimensions. Two types of clustering processes were compared, one with four clusters and another with five clusters. The results obtained by EFlow were considered satisfactory by the expert as they were significantly in agreement with his classification. In some clusters, EFlow classified correctly up to 100% of the cells. At the present time few commercial cytometry software offer equivalent clustering analysis. © 2012 IEEE.

关键词： Cytology

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Reports on Homeopathic therapy efficacy: A survey of two Brazilian newspapers

Reports on Homeopathic therapy efficacy: A survey of two Bra...

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Pan American Health Care Exchanges, PAHCE

作者： R. M. V. R. Almeida Biomedical Engineering Program COPPE/UFRJ Rio de Janeiro Brazil

The objective of this work was to identify the existence of biases on the reporting of Homeopathy efficacy in Brazilian newspapers. To this end, the online archives of two large newspapers - one in Rio de Janeiro city and one in São Paulo city - were searched for all news or reports concerning Homeopathy in the period January 2009-December 2010. The identified items were then classified as “favorable”, “unfavorable” or “neutral” in what concerns the efficacy of Homeopathic therapy. Paid advertisements and “passing” references were excluded. Thirty-one items were identified, and the results indicated an overall preponderance of “favorable”, as compared to “unfavorable“, reports (14 favorable, 7 unfavorable). In conclusion, newspaper reporting of homeopathic efficacy is not compatible with the most update scientific evidence on the topic.

关键词： Animals Diseases Pediatrics Stress Cities and towns

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Accessibility of selected hospitals and medical procedures by means of aerial and transit network-based measures

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Health Services Management Research 2003年第2期16卷 136-140页

作者： Costa, L.S. Nassi, C.D. Pinheiro, R.S. Almeida, Renan Moritz Varnier R. Biomedical Engineering Program COPPE Federal University of Rio de Janeiro Rio de Janeiro 21945-970 Brazil Transportation Program COPPE Federal University of Rio de Janeiro Rio de Janeiro 21945-970 Brazil NESC Medical School Federal University of Rio de Janeiro Rio de Janeiro 21945-970 Brazil

Objective: This report investigates the use of linear and travelled route (transit network-based) distances in estimating the accessibility of hospitals to patients, for some selected hospital admission diagnostics. Methods: For patients admitted to 14 public hospitals in Rio de Janeiro City, during 1996, under the ICD-9 headings 'Complications of Pregnancy, Childbirth and the Puerperium' and.'Disorders of the Circulatory System', average distances between the patient's district of residence and hospital of admission were calculated (both as Euclidean and as network-based distances). Data were obtained from the country's public health data processing agency. Geographic co-ordinates were obtained for districts of residence from the postal codes of the patients' residences. Distances were estimated with the TransCAD Geographical Information System, based on a map of the city transit network. There were 8654 patients admitted under the 'Complications of Pregnancy' heading and 3439 under 'Disorders of Circulatory System'. Results: Variations of up to a factor of 5.3, and up to 34km, could be identified between linear and network estimates. Conclusion: While recognizing that network estimates have advantages, the literature on accessibility frequently argues that aerial estimates are a good approximation for those. The present results show that this is not necessarily the case.

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A numerical model of the respiratory modulation of pulmonary shunt and PaO2 oscillations for acute lung injury

A numerical model of the respiratory modulation of pulmonary...

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作者： Beda, Alessandro Jandre, Frederico C. Giannella-Neto, Antonio Pulmonary Engineering Lab Biomedical Engineering Program COPPE - Federal University of Rio de Janeiro Rio de Janeiro Brazil Pulmonary Engineering Group University Clinic Carl Gustav Carus Technical University Dresden Dresden Germany

It is an accepted hypothesis that the amplitude of the respiratory-related oscillations of arterial partial pressure of oxygen (ΔPaO2) is primarily modulated by fluctuations of pulmonary shunt (Δs), the latter generated mainly by cyclic alveolar collapse/reopening, when present. A better understanding of the relationship between ΔPaO2, Δs, and cyclic alveolar collapse/reopening can have clinical relevance for minimizing the severe lung damage that the latter can cause, for example during mechanical ventilation (MV) of patients with acute lung injury (ALI). To this aim, we numerically simulated the effect of such a relationship on an animal model of ALI under MV, using a combination of a model of lung gas exchange during tidal ventilation with a model of time dependence of shunt on alveolar collapse/opening. The results showed that: (a) the model could adequately replicate published experimental results regarding the complex dependence of ΔPaO2 on respiratory frequency, driving pressure (ΔP), and positive end-expiratory pressure (PEEP), while simpler models could not;(b) such a replication strongly depends on the value of the model parameters, especially of the speed of alveolar collapse/reopening;(c) the relationship between ΔPaO2 and Δs was overall markedly nonlinear, but approximately linear for PEEP ≥ 6 cmH2O, with very large ΔPaO2 associated with relatively small Δs. © 2009 biomedical engineering Society.

关键词： Ventilation

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