abstract: Approximately 1.7 million people in the United States are living with limb loss and are in need of more sophisticated devices that better mimic human function. In the Human Machine Integration Laboratory, a powered, transtibial prosthetic ankle was designed and build that allows a person to regain ankle function with improved ankle kinematics and kinetics. The ankle allows a person to walk normally and up and down stairs, but volitional control is still an issue. This research tackled the problem of giving the user more control over the prosthetic ankle using a force/torque circuit. When the user presses against a force/torque sensor located inside the socket the prosthetic foot plantar flexes or moves downward. This will help the user add additional push-off force when walking up slopes or stairs. It also gives the user a sense of control over the device. / Dissertation/Thesis / M.S. Bioengineering 2012

Orientador: Jose Elias Tomazini / Banca: Marcelo Sampaio Martins / Banca: Jose Geraldo Trani Brandão / Banca: Luiz Carlos de Abreu / Banca: Rubens Correa Araújo / Resumo: O objetivo do estudo foi analisar a atividade elétrica muscular e a força isométrica nos membros superiores, a partir de um dispositivo de baixo custo. Para testar o dispositivo foram realizados testes em dois músculos rotadores do ombro: infraespinhoso e peitoral maior, comparando a força produzida pelo membro dominante e não-dominante e correlacionando a força isométrica com o sinal eletromiográfico. Participaram do estudo 20 (vinte) sujeitos do sexo masculino, saudáveis, com idade entre 18 e 21 anos, massa corpórea entre 55 e 90 kg (69,75 ± 10,46 kg) e com estatura entre 1,65 e 1,93 m (1,75 ± 0,05 m). Foram aplicados testes de esforço musculoesqueléticos em diferentes posições. Para comparar as médias das variáveis analisadas foi utilizada a análise de variância simples (One-Way ANOVA) e o teste de Kruskal-Wallis. O teste t de Student com significância estatística a = 5% (p < 0,05) e com a = 1% (p < 0,01) foi aplicado para comparar os valores de força média entre o membro superior direito e o membro superior esquerdo. Para verificar a correlação entre a EMG-Força, aplicou-se o teste de correlação de Pearson. O membro dominante gerou mais força que o não-dominante. Os valores normalizados de RMS e de Força apresentaram correlação significativa com 95% de confiança apenas no teste de rotação externa no membro superior esquerdo na posição de rotação externa. Na correlação entre os valores de RMS normalizados - Força Média, houve correlação significativa nos testes de rotação interna e externa no membro superior esquerdo, na posição de rotação externa. O sistema de aquisição se mostrou eficiente e novos estudos devem ser realizados, envolvendo a relação EMG-Força / Abstract: The aim of this study was to evaluate the muscle electrical activity and isometric strength in the upper limbs from a low-cost device. Tests were performed on two of the shoulder rotator muscles: infraspinatus and pectoralis major, comparing the strength produced by the dominant and non-dominant and isometric strength correlated with electromyographic signal. The study included twenty (20) male subjects, healthy and aged between 18 and 21 years, body mass index between 55 and 90 kg (69.75 ± 10.46 kg) and height between 1.65 and 1.93 m (1.75 ± 0.05 m). We applied musculoskeletal stress tests in different positions. To compare the means of the variables we used the simple analysis of variance (One-Way ANOVA) and the Kruskal-Wallis test. The Student's t- test with statistical significance = 5% (p <0.05) and = 1% (p <0.01) was used to compare the values of mean force between the right upper limb and left upper limb to verify the correlation between the EMG-Force, we applied the Pearson correlation Test. The dominant member generated more force than the non-dominant. The normalized values of RMS and Power were significantly correlated with 95% confidence test only in external rotation in the left arm in external rotation position. In the correlation between RMS values normalized - mean strength significant correlation tests of internal and external rotation in the left arm in external rotation position. The acquisition system is efficient and further studies should be conducted involving the relationship EMG-Strength / Doutor

<p> The cercopithecoid monkeys, though sharing a common body-plan, exhibit considerable behavioral, ecological, and anatomical diversity. The theme of this work is the relationship between anatomy, postural behavior, and habitat use, concentrating upon the distal forearm, wrist and hand. It incorporates an initial review of the relevant empirical and theoretical literature, and original research including anatomy, naturalistic and experimental observation, and a first detailed description of fossil forelimb material of the "giant" extinct baboon, <i>Theropithecus oswaldi</i>. Two modes of contact between hand and substrate in monkeys are distinguished. Palmigrady is characteristic of predominately arboreal species, while species that habitually walk on the ground do so using a distinctive <i>digitigrade</i> gait. The vervet monkey (<i>Cercopithecus</i> [now <i>Chiorocebus</i>] <i> aethiops</i>, s.l.) occupies many tropical, seasonal habitats, and, uniquely, is both polymorphic and polytypic with respect to hand posture. The author's fieldwork found that as expected, digitigrady is apparently favored by vervets living in drier, more open habitats. The mid section of the dissertation reviews in depth the copious and often confusing literature on primate, especially cercopithecoid, taxonomy, and the many contradictory schemes that have attempted to categorize primate positional behavior.</p><p> Variation in the intermetacarpal and other wrist joints in human subjects provides background for recognition of character states distinguishing obligate digitigrade (patas and baboon) from palmigrade (colobus) monkey genera. It is then demonstrated that, consistent with the observation of hand posture variation in living subjects, anatomical variation among individual vervet skeletons encompasses both types. Unexpectedly, the large fossil <i> T. oswaldi</i> (but not <i>T. geiada</i>) shows palmigrade features in some aspects of carpal structure. This theme is pursued in the most extensive section of the dissertation, which includes a detailed description and interpretation of fossil forelimb specimens assigned to <i>Theropithecus oswaldi</i>, from the sites of Olorgesailie (Kenya) and Olduvai Gorge (Tanzania) . The descriptions include notes comparing the fossils with extant cercopithecoids, and interpreting similarities and differences. These comparisons suggest that <i>T. oswaldi</i> did not closely resemble extant baboons in locomotor behavior, and may have been palmigrade on the ground. Finally, the concluding sections describe an innovative set of techniques that were used successfully to collect electromyographic and cineradiographic data on monkeys locomoting in a controlled laboratory setting, with a view to confirming the functional interpretation of anatomical features of living and fossil forms, and the naturalistic behavior of living vervets.</p><p>

<p> A theoretical model is proposed for the buckling of a three-dimensional vein subjected to torsion, internal pressure, and axial tension using energy conservation methods. The vein is assumed to be an anisotropic hyperelastic cylindrical shell which obeys the Fung constitutive model. Finite deformation theory for thick-walled blood vessels is used to characterize the vessel dilation in the pre-buckling state. </p><p> The pre-buckling state is identified by its midpoint and then perturbed by a displacement vector field dependent on the circumferential and axial directions to define the buckled state. The total potential energy functional of the system is extremized by minimizing the first variation with respect to the elements of the set of all continuous bounded functions on <b>R </b>³. The Euler-Lagrange equations form three coupled linear partial differential equations with Dirichlet boundary conditions characterizing the buckling displacement field under equilibrium. </p><p> A second solution method approximates the first variation of the total potential energy functional using a variational Taylor series expansion. The approximation is minimized and combined with equations of equilibrium derived from elasticity theory to yield a polynomial relating buckling eigenmodes, material parameters, geometric parameters, and the critical angle of twist which induces buckling. Various properties of the total potential energy functional specific to the problem are proved. Another solution method is outlined using the first variation approximation and the basis of the kernel of the linear transformation which maps buckling displacement amplitudes during static equilibrium. </p><p>

Made available in DSpace on 2014-06-11T19:34:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-08Bitstream added on 2014-06-13T18:45:50Z : No. of bitstreams: 1 cipolli_eac_dr_guara.pdf: 441401 bytes, checksum: cc3c201416c280ba0fbbd033bf57a0a5 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A cada dia as técnicas de reconstrução 3D vêm contribuindo para o levantamento de informações a respeito do movimento esportivo. Este trabalho teve como objetivo desenvolver um sistema de reconstrução 3D, de baixo custo, com câmeras em movimento, para a medição de um movimento submerso. Foi reconstruido o comprimento do membro inferior do nadador ao realizar um movimento de deslize submerso em quatro trechos nadados extrapolando o volume calibrado. O sistema foi composto de duas câmeras submersas com frequencia de captura de 30 Hz, sem ajustes internos, fixadas num dispositivo móvel contruído especificamente para o estudo.Como referência utilizou-se um objeto de calibração com 40 pontos previamente determinados de dimensões 3m x 1,5m x 1m. Foram verificada a precisão e a acurácia do sistema. Os valores de RMS das distancias reconstruídas ficaram entre 1,35cm e2,52cm (RMS% = 1,63%a 3,07%) e os valores de acurácia entre 1,67cm e 2,72cm. Foi aplicado o teste t e verificou-se não haver diferença significativa (p<0,05) entre os valores medidos nos quatro trechos das seis tentativas realizadas pelo nadador. O sistema apresentou medidas consistentes para esse tipo de medição. Pode-se concluir portanto que o sistema mostrou-se confiável e aplicável para futuras medições de movimentos submersos na natação / Each day the techniques of 3D-Reconstruction has contributed to the collection of information about the sports movement. This work aimed to develop a 3DRreconstruction system, low cost, with moving cameras, for measuring a moving underwater. It was reconstructed the length of the swimmer's leg when performing a movement of underwater sliding in four patch extrapolating the calibrated volume. The system was composed of two underwater cameras with capture rates of 30 Hz without internal adjustments, set on a mobile device built specifically for the study. As a reference we used a calibration object with 40 points previously determined dimensions of 3m x 1m x 1.5m. We checked the precision and accuracy of the system. The RMS values of the reconstructed distances were between 1.35 cm and 2.52 cm (RMS% = 1.63% to 3.07%) and accuracy values between 1.67 cm and 2.72 cm. We used test t and there was no significant difference (p 0.05) between the measured values of the four patches of six attempts made by the swimmer. The system showed consistent measures for this type of measurement. It can be concluded therefore that the system was reliable and applicable for future measurements of movements in swimming underwater

Made available in DSpace on 2014-06-11T19:34:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-11-10Bitstream added on 2014-06-13T21:06:52Z : No. of bitstreams: 1 galera_srg_dr_guara.pdf: 1308616 bytes, checksum: 5adff046fd36c4e14298477a81def9d3 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Com aumento de longevidade, a preocupação está voltada à acessibilidade que possibilita autonomia e mobilidade humana. O movimento do corpo humano depende da dinâmica anatômica e fisiológica entre músculos e articulações para processar o movimento que é causado por forças centrípetas. A locomoção humana é produzida pela transferência do corpo no espaço, que depende da marcha, evento de alta complexidade para análise sobre reabilitação e biomecânica. Nessa conjuntura, o escopo deste estudo foi avaliar a atividade muscular e correlacionar as variáveis (Razão, Co-contração e Pressão Plantar no calcâneo) para análise do esforço biomecânico do tornozelo durante a marcha em aclive, declive e plano. Sob protocolo n.138/2010 de aprovação do projeto por Comitê de Ética em Pesquisa, a coleta de dados foi aplicada em amostra de 11 sujeitos do gênero feminino, com idade entre vinte e cinquenta anos, saudáveis e com marcha independente. Para o trajeto se utilizou uma rampa com inclinação de 20º, cujo início foi demarcado com o toque sobre a marca que continha o pushbutton para registro de sinais eletromiográficos e força plantar em sincronismo. As participantes utilizaram um par de sandálias sensorizadas desenvolvido com quatro células de carga para mensurar as pressões plantares por meio de extensão que ligava cada célula ao sistema de aquisição de dados Spider 8®. Os testes de Kruskall-Wallis e Mann-Whitney possibilitaram a avaliação de quatro músculos dos tornozelos (Tibial Anterior Direito e Esquerdo, e Gastrocnêmio Medial Direito e Esquerdo). Durante a Passada e a Fase de Apoio, estes músculos realizaram esforços significativamente superiores no aclive e inferiores no declive. Já, na Fase de Balanço, apenas o músculo Tibial Anterior direito apresentou diferença significativa... / With increasing longevity, the concern is with the accessibility that allows autonomy and human mobility. The movement of the human body depends on the anatomical and physiological dynamics of muscles and joints to handle the movement that is caused by centripetal forces. The human locomotion is produced by the transfer of the body in space, which depends on the march, an event of high complexity for analysis of rehabilitation and biomechanics. At this juncture, the scope of this study was to evaluate the muscular activity and to correlate the variables (Reason, Co-contraction and Plant Pressure on the heel) to analyze the biomechanical stress of the ankle during walking uphill, downhill and flat. Under Protocol n.138/2010 of project approval for Commission of Ethic in research , the data collection was applied in a sample of 11 female subjects, aged between twenty and fifty years, healthy and independent walking. For the path we used a ramp inclined 20°, whose beginning was marked with the touch above the insole containing the pushbutton for recording electromyography signals and power plant in sync. Participants used a pair of sandals sensorized enveloped with four load cells to measure Plant Pressures through long connecting each cell to the data acquisition system Spider 8®. The Kruskall-Wallis and Mann- Whitney enable the evaluation of four muscles of the ankle (anterior tibialis Right and Left, Right and Left Medial Gastrocnemius). During the Footstep and Support Phase, these muscles have made efforts significantly higher in the uphill and minor in the downhill. Already, in the Swing Phase, only the right anterior tibial muscle showed Root Mean Square, the tibialis anterior Right muscle showed difference significant electromyography activity, was greater in uphill. The reason between... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:34:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-03-08Bitstream added on 2014-06-13T20:05:59Z : No. of bitstreams: 1 cortez_pjo_dr_guara.pdf: 1389354 bytes, checksum: cb0ee16ef2eeda94520b72792aeb8d14 (MD5) / O objetivo do estudo foi analisar a atividade elétrica muscular e a força isométrica nos membros superiores, a partir de um dispositivo de baixo custo. Para testar o dispositivo foram realizados testes em dois músculos rotadores do ombro: infraespinhoso e peitoral maior, comparando a força produzida pelo membro dominante e não-dominante e correlacionando a força isométrica com o sinal eletromiográfico. Participaram do estudo 20 (vinte) sujeitos do sexo masculino, saudáveis, com idade entre 18 e 21 anos, massa corpórea entre 55 e 90 kg (69,75 ± 10,46 kg) e com estatura entre 1,65 e 1,93 m (1,75 ± 0,05 m). Foram aplicados testes de esforço musculoesqueléticos em diferentes posições. Para comparar as médias das variáveis analisadas foi utilizada a análise de variância simples (One-Way ANOVA) e o teste de Kruskal-Wallis. O teste t de Student com significância estatística a = 5% (p < 0,05) e com a = 1% (p < 0,01) foi aplicado para comparar os valores de força média entre o membro superior direito e o membro superior esquerdo. Para verificar a correlação entre a EMG-Força, aplicou-se o teste de correlação de Pearson. O membro dominante gerou mais força que o não-dominante. Os valores normalizados de RMS e de Força apresentaram correlação significativa com 95% de confiança apenas no teste de rotação externa no membro superior esquerdo na posição de rotação externa. Na correlação entre os valores de RMS normalizados - Força Média, houve correlação significativa nos testes de rotação interna e externa no membro superior esquerdo, na posição de rotação externa. O sistema de aquisição se mostrou eficiente e novos estudos devem ser realizados, envolvendo a relação EMG-Força / The aim of this study was to evaluate the muscle electrical activity and isometric strength in the upper limbs from a low-cost device. Tests were performed on two of the shoulder rotator muscles: infraspinatus and pectoralis major, comparing the strength produced by the dominant and non-dominant and isometric strength correlated with electromyographic signal. The study included twenty (20) male subjects, healthy and aged between 18 and 21 years, body mass index between 55 and 90 kg (69.75 ± 10.46 kg) and height between 1.65 and 1.93 m (1.75 ± 0.05 m). We applied musculoskeletal stress tests in different positions. To compare the means of the variables we used the simple analysis of variance (One-Way ANOVA) and the Kruskal-Wallis test. The Student’s t- test with statistical significance = 5% (p <0.05) and = 1% (p <0.01) was used to compare the values of mean force between the right upper limb and left upper limb to verify the correlation between the EMG-Force, we applied the Pearson correlation Test. The dominant member generated more force than the non-dominant. The normalized values of RMS and Power were significantly correlated with 95% confidence test only in external rotation in the left arm in external rotation position. In the correlation between RMS values normalized – mean strength significant correlation tests of internal and external rotation in the left arm in external rotation position. The acquisition system is efficient and further studies should be conducted involving the relationship EMG-Strength

abstract: Muscular weakness is a common manifestation for Stroke survivors and for patients with Anterior Cruciate Ligament reconstruction leading to reduced functional independence, especially mobility. Several rigid orthotic devices are being designed to assist mobility. However, limitations in majority of these devices are: 1) that they are constrained only to level walking applications, 2) are mostly bulky and rigid lacking user comfort. For these reasons, rehabilitation using soft-robotics can serve as a powerful modality in gait assistance and potentially accelerate functional recovery. The characteristics of soft robotic exosuit is that it’s more flexible, delivers high power to weight ratio, and conforms with the user’s body structure making it a suitable choice. This work explores the implementation of an existing soft robotic exosuit in assisting knee joint mechanism during stair ascent for patients with muscular weakness. The exosuit assists by compensating the lack of joint moment and minimizing the load on the affected limb. It consists of two I-cross-section soft pneumatic actuators encased within a sleeve along with insole sensor shoes and control electronics. The exosuit actuators were mechanically characterized at different angles, in accordance to knee flexion in stair gait, to enable the generation of the desired joint moments. A linear relation between the actuator stiffness and internal pressure as a function of the knee angle was obtained. Results from this characterization along with the insole sensor outputs were used to provide assistance to the knee joint. Analysis of stair gait with and without the exosuit ‘active’ was performed, using surface electromyography (sEMG) sensors, for two healthy participants at a slow walking speed. Preliminary user testing with the exosuit presented a promising 16% reduction in average muscular activity of Vastus Lateralis muscle and a 3.6% reduction on Gluteus Maximus muscle during the stance phase and unrestrained motion during the swing phase of ascent thereby demonstrating the applicability of the soft-inflatable exosuit in rehabilitation. / Dissertation/Thesis / Masters Thesis Biomedical Engineering 2018

<p> Image-based modeling and simulation has become an important analytic and predictive tool for patient-specific medical applications, including large-scale in silico patient studies, optimized medical device design, and custom surgical guides and implants via additive manufacturing. The pipeline for patient-specific modeling and simulation is: image acquisition, image segmentation, surface generation, mesh generation, physics-based modeling and simulation, and clinical application. This research establishes a semi-automatic workflow for these steps, which includes a novel image-based meshing tool <i> Shabaka.</i> The toolchain is demonstrated by modeling the mechanics of a beating human heart based on magnetic resonance imaging (MRI) data. </p><p> The Shabaka workflow ensures robust execution of each step of the pipeline. Medical images are processed and segmented using thresholding, region-growing, and manual techniques. Watertight surface meshes are extracted from image masks using a novel Voronoi-based algorithm. For scientific computing purposes, surface meshes are supplied either to tetrahedral meshing routines for conventional finite element approaches, or to a robust polyhedral mesh generation tool for a novel polyhedral finite element approach. A polyhedral finite element code is explored, that retains most of the favorable properties of conventional finite element methods, while reducing the system size by up to an order of magnitude compared to conventional techniques for the same input surface. </p><p> In conjunction with a cardiac simulation code, the workflow is utilized to model finite-deformation cardiac mechanics. A quadratic tetrahedral mesh is generated from MRI data of the human heart ventricles. The constitutive law is comprised of an incompressible orthotropic hyperelastic stress response for the myocardium, plus an electrical activation-dependent active stress for the muscle fibers. Muscle fiber orientations are generated using a rule-based approach. Electrical activation times are read from a coupled electrophysiology code. A lumped circulatory model is used to impose time-dependent ventricular volume constraints. Simulation results are presented. The same mechanics are also implemented for the polyhedral finite element mesh, and preliminary verification results are presented. </p><p> The toolchain used in performing image-based cardiac mechanics simulations makes important improvements to the speed and robustness of image-based modeling techniques. As efforts continue to mature, so too does the promise for simulation to impact and improve healthcare.</p><p>

Made available in DSpace on 2014-06-11T19:28:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-01-28Bitstream added on 2014-06-13T20:58:30Z : No. of bitstreams: 1 santos_jlp_me_guara.pdf: 1876074 bytes, checksum: 4123f2daecb149e7c9c340aaff7844f8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este estudo tem como objetivo elaborar e validar um protótipo de plataforma proprioceptiva que possibilite a mensuração e o monitoramento do comportamento cinemático dos estímulos perturbatórios gerados. Considerando que atualmente, a avaliação do equilíbrio postural em plataformas instável é realizada de forma qualitativa, sendo observado o quanto a plataforma oscilou, a estratégia proposta neste estudo permite quantificar o fenômeno oscilatório, permitindo futuras comparações entre exames, isto como uma forma de medida avaliativa dos participantes. Foi elaborada uma plataforma oscilatória que possibilitava a mensuração do seu deslocamento angular através de um potenciômetro. Para a validação do equipamento utilizou-se a técnica da videogrametria, sendo assim, durante a movimentação da plataforma coletou-se dados provenientes da plataforma e do potenciômetro. A plataforma instável construída e instrumentalizada neste trabalho foi capaz de mensurar e monitorar o comportamento cinemático dos estímulos perturbatórios gerados durante a sua movimentação, apresentando alto valor de correlação. Desta forma, pode-se substituir a técnica de videogrametria pela utilização do potenciômetro, tornando o exame mais prático. Este equipamento poderá ser útil para o estudo minucioso do equilíbrio e da estabilidade postural, no que tange a relação entre os estímulos perturbatórios gerados e a resposta motora do testado / This study aims to develop and validate an oscillating platform which enables the measurement and monitoring of the kinematics of the stimuli generated disturbing. Whereas today, the assessment of postural balance in an unstable platform is performed in a qualitative way, observing how the platform oscillated, the strategy proposed in this study to quantify the oscillatory phenomenon, allowing for future comparisons between tests, this measure as a form of evaluative participants. A oscillating platform was developed that allowed the measurement of its angular displacement with a potentiometer. For the validation of equipment used the technique of videogrammetry, so during the platform movement data was collected. The unstable platform built and manipulated in this study was able to measure and monitor the kinematics of the stimuli generated disturbing when they are moving at a high correlation value. Thus, one can replace the technique of videogrammetry the use of potentiometer, making the test more practical. This equipment may be useful for the detailed study of balance and postural stability, regarding the relationship between stimuli and motor response disturbing generated the test