http://hdl.handle.net/11422/85 Fri, 10 Apr 2026 11:17:44 GMT 2026-04-10T11:17:44Z http://hdl.handle.net/11422/28418 Title: Avaliação da variação escala de cinza em imagens ultrassônicas de tecidos biológicos ex-vivo em função da mudança temperatura Author(s)/Inventor(s): Rigueira, Juliana Gabardo Advisor: Pereira, Wagner Coelho de Albuquerque Abstract: Ultrasonography is one of the most used diagnostic imaging methods today due to its low cost and easy access. However, it does not present an image with a level of detail as observed with the magnetic resonance technique, e.g. In view of this, a new modality of ultrasound image processing that uses temperature variation as a means of disturbing the environment for obtaining a better-quality contrast, it was proposed by Teixeira et al., 2018. Where the theory of variation of backscattered energy - changes in backscattered energy (CBE) was used. In the same line of research, it was found that media with a greater number of lipid scatterers cause an increase in the CBE curve when heated, while media with aqueous scatterers cause a decline in the curve when subjected to the same conditions. In addition, it was noted that images taken at different temperatures showed different contrast, which led to believe that it would be possible to observe changes in the intensity of the ultrasonic signal with the heating of the medium. Thus, the present study aims to determine the smallest possible region in images of fresh pig fat and muscle tissues, whose variation in pixel intensity in shades of gray generates a noticeable contrast to the eyes of the observer. This variation is the result of the change in the ultrasonic signal generated in the biological tissue images during the temperature increase. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação Tue, 01 Mar 2022 00:00:00 GMT http://hdl.handle.net/11422/28418 2022-03-01T00:00:00Z http://hdl.handle.net/11422/27860 Title: Repetibilidade e reprodutibilidade da calibração de sensor de fluxo de orifício variável com o método da seringa Author(s)/Inventor(s): Trajano, Vinícius Siqueira Advisor: Tavares, Frederico Caetano Jandre de Assis Abstract: This work evaluated the repeatability and reproducibility of the calibration of a variable orifice flowmeter using the fixed volume syringe method, focusing on the possible effects of syringe stroke direction and different waveforms during calibration. We compared both sides of the flowmeter (W and B) in configurations with the side not connected to the syringe open to the room or connected to a tube. For each of the 4 possible combinations, sinusoidal flows were generated with an automated syringe. Additionally, only for the B side connected to the syringe without the tube on the W side, constant flows generated by the automated syringe, and flows generated manually by two operators (1 and 2) using a calibration syringe, were applied. Three measurements were performed for each configuration and one of them was used to generate polynomials of 5th degree for each flow direction. We considered errors of volume measurement within the range of ±3% as acceptable. For sinusoidal flows, all calibrations for the emptying syringe, and the one for the B side filling the syringe without the tube on the W side, showed repeatability. No calibration was reproducible when applied to measurements with the syringe moving in the opposite direction. For constant or manually generated flows, there was repeatability only for calibrations with the emptying syringe. When a calibration was applied to a signal from a different waveform, only the one generated by operator 1 for the emptying syringe and applied to sinusoidal flows showed acceptable errors. These results support that calibration should be performed with the syringe motion in a direction that resembles how flow is generated during application, however other factors that may affect calibration, such as other circuit assemblies and gas compositions, were not evaluated. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação Wed, 01 Jun 2022 00:00:00 GMT http://hdl.handle.net/11422/27860 2022-06-01T00:00:00Z http://hdl.handle.net/11422/27859 Title: Associação da demanda por serviços de saúde e medicamentos com estrutura demográfica, renda e fragilidade dos idosos Author(s)/Inventor(s): Moraes, Ricardo Montes de Advisor: Almeida, Rosimary Terezinha de Abstract: Demand projections are useful to plan medicines’ and health services’ supply and to support public policies’ formulation. Growth in demand for medicines and private health services associated with demographic changes in Brazil was estimated with data from Brazil’s Household Budget Survey (POF) and the country’s statistical office’s Population Projection. For medicines, demand is expected to grow 50.7% in the period between 2020 and 2060 and, for services, 43.3%. This means annual increases of 0.8% and 0.7% in per capita demand for these products. The income elasticity of demand for medicines and health services was also estimated. For medicines, it ranged between 0.25 and 0.85 depending on the percentiles of the income distribution analyzed. For health services, the estimated elasticity was between 0.53 and 0.89. A Frailty Index (FI), based on Brazil’s National Health Survey (PNS), was estimated for people aged 60 years old and over. Using statistical matching methods, two FI estimates were imputed on POF’s database, defining a range of possible values for the index in this survey. The analysis of associations between the demand for medicines and health status, demographic structure and income is what makes possible to evaluate and update projections when more up-to-date information on population profiles becomes available. More than growth rates, these variables’ associations – and the methods used to estimate them – are this thesis’s main contribution to the demand for medicines and private health services’ estimation in Brazil. Publisher: Universidade Federal do Rio de Janeiro Type: Tese Thu, 01 Sep 2022 00:00:00 GMT http://hdl.handle.net/11422/27859 2022-09-01T00:00:00Z http://hdl.handle.net/11422/27858 Title: Avaliação da resposta cerebral a estímulo térmico não doloroso em regime permanente Author(s)/Inventor(s): Teixeira, Mateus Costa Advisor: Criollo, Carlos Julio Tierra Abstract: Temperature perception happens due to the capacity of specific afferent fibers - thin fibers - to conduct information about cold and heat, painful or not. Many peripheral neuropathies begin with the progressive destruction of these fibers, and therefore, the understanding of this process, from the stimulus transduction to the cortical response, is fundamental. There is already some knowledge about pain perception, however, there is a lack of information in the literature about the cortical processing of non-painful thermal stimuli. In this work, we analyzed the electroencephalographic signal of two experimental groups with different protocols of non-painful thermal stimulation. Seeking to investigate how brain regions are connected during these stimuli, the signals were processed using Magnitude Squared Coherence (MSC). A synchronism between the hemispheres in the frontal and parietal regions during thermal stimulation was found in the delta band. Within hemispheres, the frontal, parietal and central regions also presented higher coherence during stimulation for this band. No significant difference was found between heat and cold MSC values. The present work consolidates and contributes information for a better understanding of brain functioning during non-painful thermal stimulation. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação Tue, 01 Feb 2022 00:00:00 GMT http://hdl.handle.net/11422/27858 2022-02-01T00:00:00Z