Spatio-temporal variation in action intervals during ventricular fibrillation (VF) suggestthat the excitable gap may also be distributed spatio-temporally. The observation leadus to hypothesize that distributed pacing can be used to modify and entrain electricalactivation during VF. We tested this hypothesis using simulated VF and animal studies. We simulated VF in a 400 by 400 cell matrix. Simulation results showed that activationpattern could be entrained using spatially distributed stimulation. Up to a certain limit,increasing stimulus strength and density led to improved entrainment. Best entrainmentwas obtained by pacing at a cycle length similar to the intrinsic cycle length. In order to verify whether activation could be entrained experimentally, eight opticallyisolated biphasic TTL addressable stimulators were fabricated. Distributed stimulationwas tested during electrically induced VF in two canines and two swine. Resultsshowed that electrical activation could be entrained in both species. Similar to that insimulation, better entrainment was obtained with denser pacing distribution and atpacing cycle length similar to the intrinsic cycle length. As expected, entrainment wasaffected by tissue thickness. Our results show that spatio-temporally distributed pacingstrength stimuli can be used to modify activation patterns during VF.

The human being may no longer be reduced to the bounds of organic matter. An organism – a life form constructed from interdependent components that maintain various vital processes – may now reach beyond the limits of biological materials. Beyond the skin, thumbs, eyes, and organs of the average human being, we may notice the mutually dependent system of parts, functioning simultaneously as autonomous and interconnected components. These organic systems are now capable of fusing with foreign systems that help maintain the vitality of the macroscopic system – the human. Between human and machine, recent advancements in technology and prosthetic designs have enabled humans to graft with mechanized and computerized systems, challenging the preconception of what it is to be human. The advanced prosthesis has become an integrated extension of the human body. This realization begs the question: how intimate can architecture become? Pros+Tithenai analyzes the body’s imposition on space - transforming, manipulating, conforming to the void – and the equivalent imposition of space on the body. Pros+Tithenai examines how the human body unfolds in the creases between architecture, biology, engineering, cybernetics, psychology, and emerges reassembled.

Aims: The primary physiotherapeutic aims of the study were to validate a manual physiotherapy evaluation technique in the assessment of cervical biomechanical dysfunction, and to test the effectiveness of a manual physiotherapy treatment technique in the correction of cervical biomechanical dysfunction. The primary educational aims were to test the effectiveness and safety of a therapeutic exercise programme for the correction of biomechanical dysfunction as well as the effectiveness of a neck rehabilitation programme for improving neck muscle strength. Design: A four group experimental design with three pre-test - post-test groups and a control group was used for the investigation. Sample: The subjects were South African schoolboy rugby players between the ages of 15 and 18 years. Groups I and 2 presented with biomechanical dysfunction of their cervical spines, Group 3 had no biomechanical dysfunction of their cervical spines and the players of Group 4, the control group, presented with or without biomechanical dysfunction of their cervical spines. Each group consisted of 25 players. Method: Group I received manual physiotherapy with x-rays before and after treatment. Groups 2 and 3 performed a therapeutic exercise programme, with before and after x-rays, and Group 4 received no intervention between their sets of x-rays. Following the second set of x-rays all the players from Groups I, 2 and 3 performed the neck rehabilitation programme after which a third set of x-rays were taken. Results: The results validated the manual physiotherapy evaluation technique. The manual therapy treatment technique used in the treatment of Group I showed highly significant improvements in cervical biomechanical function. Results for Group 2 following the therapeutic exercise programme showed moderate practically significant improvements in cervical biomechanical dysfunction. The therapeutic exercise programme for the correction of biomechanical dysfunction was found to be very safe with only small significant changes in x-ray measurements (Group 3). The results of the control group showed a negative trend of small statistical significance. A highly significant improvement in cervical circumference as moderate significant improvement in biomechanical function was found following the neck rehabilitation programme. Conclusion: It could therefore be concluded that the manual physiotherapy evaluation technique for motion segment analysis was indeed valid in determining biomechanical dysfunction of the cervical spine. The manual physiotherapy treatment technique as well as the therapeutic exercise programme for the correction of biomechanical dysfunction was found to be effective in the correction of cervical biomechanical dysfunction. It could further be concluded that the therapeutic exercise programme was safe to be performed by players without biomechanical dysfunction. The neck rehabilitation programme was effective in improving cervical circumference as well as cervical biomechanical function. / Thesis (Ph.D. (Education))--North-West University, Potchefstroom Campus, 2005.

We describe a semi-automatic technique for modeling and animating complex musculoskeletal systems using a strand based muscle model. Using our interactive tools, we are able to generate the motion of tendons and muscles under the skin of a traditionally animated character. This is achieved by integrating the traditional animation pipeline with a biomechanical simulator capable of dynamic simulation with complex routing constraints on muscles and tendons. We integrate our musculoskeletal modeling and animation toolkit into a professional 3D production environment, thereby enabling artists and scientists to create complex musculoskeletal systems that were previously inaccessible to them. We demonstrate the applications of our tools to the visual effects industry with several animations of the human hand and applications to the biomechanics community with a novel model of the human shoulder.

In silico models of intracranial aneurysm (IA) evolution aim to reliably represent the mechanical blood flow environment, the biology of the arterial wall and, crucially, the complex link between the two, namely the mechanobiology of healthy and diseased arteries. The ultimate goal is to create diagnostic tools for personalized management and treatment of aneurysm disease. Towards that target, the work presented in this thesis aims to establish a directly interactive link between experimental (in vivo and in vitro) and computational work for biologically and clinically relevant research on aneurysm disease. Mechanobiological hypotheses were firstly investigated in a novel 1D mathematical conceptual model of aneurysm evolution: for the first time these included representations of endothelial heterogeneity and smooth muscle cell (SMC) active stress response and apoptosis. The 1D investigations analysed and assessed the role of wall shear stress (WSS) homeostasis in elastin degradation, and the evolving role of the adventitia as a protective sheath in health and primary load-bearer in disease. The 1D framework was applied to a specific patient's aneurysm using both imaging and histological data to parameterise the model, calculating a material parameter for the adventitital collagen. The predicted evolution captured aspects of tissue changes measured with time focusing on the remodelled tissue wall thickness consistent with the experimental measurements, and physiological cyclic deformation in order to propose an approach to modelling adventitia's adaptive role to load bearing. Furthermore, an existing Fluid-Solid-Growth (FSG) computational framework was adapted and calibrated for the same patient-specific case with the help from the experimental data and the analysis from the 1D framework. This FSG model quantifies the arterial mechanical environment and captures the mechanical response of the fibrous arterial constituents. Comparing 1D and 3D investigations to establish consistency for our models, the 3Dmodel tested the hypothesis of WSS homeostasis, additionally introducing the element of spatial heterogeneity in the definition, and a new hypothesis linking cyclic deformation with collagen growth that ensures a physiological mechanical environment in stabilised aneurysms. Moreover, the FSG framework was applied in a specific rabbit aneurysm case and extended to link growth and remodeling to the detailed representation of the pulsatile blood flow mechanical environment. This research illustrates the power of computational modelling when coupled with rich data sets on the physiology, histology and geometry of healthy and diseased vascular tissue. In particular, the integrative modelling framework provides the foundation for establishing mechanobiological links crucial to aneurysm progression, and a basis for further research towards creating reliable aneurysm clinical tools.

In golf, a range of shot types are necessary for successful performance, with driving and iron-play constituting the long-game. It is possible to vary long-game shots through altered trajectory, for example, by utilising right-to-left or left-to-right ball flight curvature, providing course management advantages. However, how golfers vary their biomechanics to achieve different trajectories is not scientifically understood. Therefore, the purpose of this thesis was to biomechanically investigate different trajectories hit with the same club. To investigate shot trajectories, accurate measures of performance were necessary. Launch monitors (TrackMan Pro IIIe and Foresight GC2+HMT) are bespoke technologies capable of tracking the clubhead and ball through impact. However, their accuracy for scientific research has not been independently validated. Therefore, a novel purpose-designed tracking method was developed using a three-dimensional optical tracking system (GOM). The accuracy of this method was validated and the system used as the benchmark to which the two launch monitors were compared through limits of agreement. The results showed, in general, the launch monitors were in closer agreement to the benchmark for ball parameters than clubhead. High levels of agreement were found for ball velocity, ball path, total spin rate and backspin. However, poorer agreement was shown for ball sidespin and spin axis as well as clubhead velocity, clubhead path and clubhead orientation. Consequently, the launch monitors were deemed unsuitable for inclusion in scientific research across a range of impact parameters. Draw and fade trajectories with a driver and draw, fade and low trajectories with a 5-iron were investigated biomechanically. The clubhead and ball were tracked using the optical method developed in this thesis. Key biomechanical variables (address position and whole-swing) were defined based on coaching theory. Statistically, analysis of variance (address) and principal components analysis (whole-swing), were used to compare draw against fade and low against natural trajectories. Multivariate correlation was used to identify swing pattern similarities between golfers. The group-level comparison showed draw-fade address differences whereby for draw trajectories, the ball was positioned further away from the target, the lead hand further towards the target and the pelvis, thorax and stance openness closed relative to the target line. Over the whole-swing, the draw when compared to the fade demonstrated a pelvis rotation, more rotated away from the target with later rotation; lumbar forward flexion, with slower extending in the downswing; lumbar lateral flexion, with more flexion towards the trail throughout and prolonged trail flexing through ball contact; thorax lateral flexion, with greater, slower lead flexing in the backswing and greater, more prolonged trail flexing in the downswing; pelvis translation further towards the target throughout, with earlier forward translation and centre of pressure, with an earlier, quicker, greater forward shift. Cluster differences were evident, with both Clusters I (57% of golfers with the driver) and II (71% of golfers with the 5-iron) showing greater, earlier thorax rotation towards the target and a tendency for greater lumbar forward flexion over the whole-swing (Cluster II) and backswing (Cluster I). For the group-level low-natural comparison, golfers positioned the ball further away from the target and their lead hand further towards the target for low trajectories. Further, Cluster IV (45% of golfers), narrowed their stance width and laterally flexed their thorax towards the lead, for the same trajectories. Over the whole-swing, the low when compared to the natural showed the pelvis translated towards the target throughout, with later, lesser forward shift for the low trajectories. Furthermore, centre of pressure displayed a greater forward shift for the same shots. Finally, both clusters (Cluster III 36% of golfers and Cluster IV) differed in lumbar forward flexion when playing low trajectories; over the backswing, Cluster III extended, whereas Cluster IV flexed. Cluster IV also showed greater extending in the downswing. Finally, Cluster IV showed more lumbar lateral flexion towards the lead throughout. The results of this study have implications for scientific researchers as well as golf coaches, club-fitters and professionals. Commercially available launch monitors appear accurate enough for coaching applications, however caution is needed for scientific research when tracking a range of clubhead and ball parameters. Furthermore, changes in biomechanics when playing different trajectories has implications for future research and interpretation of published work, as well as for coaching theory. Future work following this thesis could utilise the optical tracking method to validate further commercial systems and for more detailed experimental investigation of clubhead-ball impacts. Furthermore, additional biomechanical investigation into a wider range of shot trajectories across more variables could be conducted, with a more in-depth understanding gained from principal components analysis and golfer clustering.

Orientador: Eduardo Piza Pellizzer / Coorientador: Fellippo Ramos Verri / Resumo: Proposição: O propósito do estudo foi estudar o comportamento biomecânico de próteses de três elementos implantossuportadas diante das seguintes variáveis: união (coroas unitárias e esplintadas: em linha reta e em posicionamento tripoidal), comprimento e diâmetro do implante, além da redução do número de implantes (pôntico central), utilizando a metodologia de elementos finitos 3D. Material e Método: Vinte e seis modelos tridimensionais foram simulados com o auxílio dos programas InVesalius, Rhinoceros 4.0 e Solidworks 2016. Cada modelo representou uma seção de osso da região posterior maxilar, na forma de um bloco de osso tipo IV (cortical e esponjoso), com a presença de prótese de três elementos suportada por dois ou três implantes, do tipo hexágono externo, em diferentes situações clínicas, variando os fatores união (coroas unitárias e esplintadas: em linha reta e em posicionamento tripoidal), comprimento, diâmetro e número de implantes. Os desenhos tridimensionais foram exportados ao programa de pré- e pós- processamento FEMAP 11.1.2 para a geração da malha e aplicação de carga de 400N axial e 200N oblíqua (45°). Após a resolução do problema matemático por meio do programa de elementos finitos Nei Nastran 11.1, os resultados foram visualizados através de mapas de Tensão Máxima Principal (MPa) e Microdeformação (µε) para tecido ósseo cortical e mapas de Tensão von Mises (MPa) para parafuso de fixação. Resultados: De um modo geral, modelos com coroas esplintadas associadas ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Objective: The aim of this study was to analyze the biomechanical behavior of three-unit fixed prosthesis varying the union (single crowns and splinted crowns: straight-line and offset implant configurations), length, diameter, and the number of implant (supported by two or three implants) by 3D finite element analysis. Material and Methods: Twenty-six 3-D models were simulated with the software's In Vesalius, Rhinoceros 4.0, SolidWorks 2010 and. Each model represented a posterior maxillary bone section simulating type IV bone (cortical and spongy), with presence of 3-units fixed prosthesis supported by two or three dental implants, external hexagonal connection, in different clinical situations, varying the factors union (single crowns and splinted crowns: straight-line and offset implant configurations), length and diameter. The 3D models were exported to the software FEMAP 11.1.2 for pre- and post- processing and mesh generation besides load definition (400N vertical and 200N oblique,45°). After, the models were solved by NeiNastran 11.1 finite element software and the results were visualized by maximum principal stress (MPa) and microstrain (µε) maps to cortical bone tissue and von Mises stress (MPa) map to fixation screws. Results: Overall, the models with splinted crowns associated with offset implant placement showed the best biomechanical behavior. The reduction in the number of implants generated a biomechanical behavior. The increase of the implant diameter in the m... (Complete abstract click electronic access below) / Doutor

Made available in DSpace on 2015-06-17T19:34:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-24. Added 1 bitstream(s) on 2015-06-18T12:48:45Z : No. of bitstreams: 1 000831387_20200101.pdf: 91654 bytes, checksum: 9d628a0f5bfa069738c42a4dfe58e2e1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Proposição: O propósito deste estudo foi analisar a distribuição de tensão/deformação no tecido ósseo e na distribuição de tensão nos componentes protéticos, implantes e parafusos de fixação, geradas pelas forças oclusais sobre próteses de três elementos implantossuportadas unitárias e esplintadas variando-se a localização dos implantes (alinhados e em distribuição tripoidal), o uso de pôntico central e de pôntico em cantilever mesial e distal, por meio do método dos elementos finitos tridimensionais. Material e Método: Seis modelos tridimensionais (3D) foram constituídos de um bloco ósseo maxilar referente à região do primeiro pré-molar ao primeiro molar direito, apresentando dois ou três implantes do tipo hexágono externo (HE) de 4,0 x 10 mm, suportando prótese de três elementos metalo-cerâmica parafusada, com as seguintes variações: M1 - três implantes alinhados com coroas unitárias; M2 - três implantes alinhados com coroas esplintadas; M3 - três implantes em posicionamento tripoidal; M4 - dois implantes com pôntico central; M5 - dois implantes com pôntico em cantilever mesial; M6 - dois implantes com pôntico em cantilever distal. A força aplicada foi de 400N em direção axial, com 50N em cada ponta de cúspide, e 200N oblíqua, com 50N, aplicados em 45º, em cada ponta da cúspide vestibular. Mapas de von Mises foram utilizados para avaliar componentes protéticos, implantes e parafusos de fixação. Os mapas de Tensão Máxima Principal e microdeformação foram utilizados como critério para análise do tecido ósseo. Resultados: A esplintagem (modelos M2 e M3) foi capaz de reduzir os valores de tensão de von Mises nos parafusos de fixação, principalmente para o modelo M3. A redução do número de implantes (M4, M5, M6) ocasionou... / Objective: The aim of this study was to assess the stress/strain distribution on bone tissue and stress distribution in the abutments, implants and fixation screws, generated by occlusal force under three-unit fixed prostheses supported by two or three implants in the posterior maxilla, varying the location of the implants (straight-line and offset), using of bridge, and mesial and distal cantilever extension by 3D finite element methods. Material and Methods: Six 3-dimensional models were developed. Each model simulated a bone block (type IV) of posterior maxillary segment, with two or three external hexagon (HE) of 4.0 x 10 mm, supporting three-unit fixed prostheses, which: M1 - straight-line implants supporting single crowns; M2 - straight-line supporting three-unit splinted prosthesis; M3 - offset implant supporting three-unit splinted prosthesis; M4 - three-unit splinted prosthesis central bridge; M5 - three-unit splinted prosthesis mesial cantilever extension; M6 - three-unit splinted prosthesis distal cantilever extension. The applied forces were 400N axial and 200N oblique. The stress in the abutments, implants and fixation screws was plotted by von Mises' criteria. The stress and strain on cortical bone was plotted by maximum principal stress and microstrain criteria, respectively. Results: The splinting (M2 and M3) decreased the stress values in the fixation screws, mainly for M3. The decrease of implant number (M4, M5, M6) caused an unfavorable biomechanical behavior for analyzed structures. In situations of rehabilitations with two implants, the use of bridge (M4) showed stress and strain distribution more favorable for analyzed structures. Conclusion: The splitting was effective on stress decreasing... / FAPESP: 12/24893-1

Made available in DSpace on 2014-06-11T19:28:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-01-26Bitstream added on 2014-06-13T19:26:51Z : No. of bitstreams: 1 pereira_sstc_me_guara.pdf: 3610434 bytes, checksum: da234218018e1309611898e259e36014 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As atividades realizadas em meio aquático sofrem interferência das propriedades físicas peculiares ao mesmo. O salto vertical é uma habilidade esportiva muito utilizada em programas de reabilitação, principalmente em trabalhos de pliometria. O objetivo deste estudo foi pesquisar as forças envolvidas no salto vertical praticado em ambiente aquático e terrestre e as interdependências entre as variáveis cinéticas e cinemáticas dos mesmos. Para tal foi utilizada uma amostra composta por dez sujeitos, todos do sexo feminino, com idade média de 11,6 ± 1,35, praticantes de ginástica rítmica. Os sujeitos realizaram uma série de três saltos com contra movimento, consecutivos, sobre plataforma de força no solo, repetindo o mesmo procedimento dentro d’água. Para realização do experimento foi utilizada a técnica de cinemetria para mensuração de ângulo de flexão de joelhos e altura do salto e uma plataforma de força para mensuração das forças de reação vertical do solo. Os resultados foram analisados através da correlação de Pearson, com nível de significância de 5%. Através dos resultados obtidos observou-se que no salto executado em ambiente aquático a altura atingida, velocidade média e tempo de vôo foram maiores e a força de impacto em membros inferiores reduzida, comparados com os resultados obtidos no solo. As correlações foram evidentes entre altura do salto e velocidade de saída, em ambos ambientes. O presente trabalho deve servir como base para a elaboração de programas de treinamento envolvendo o salto, em meio aquático e terrestre, como em atividades de pliometria. Novas pesquisas devem ser realizadas, utilizando uma população praticante de modalidade esportiva que tenha o salto vertical como ação primordial para o bom desempenho na execução da mesma. / The activities carried out in the aquatic environment suffer interference from physical properties peculiar to it. The vertical jump is a sporting skill widely used in rehabilitation programs, especially in studies of plyometric. The aim of this study was to investigate the forces involved in the vertical jump practiced in aquatic and terrestrial environment and the interdependence of the kinetic and kinematic variables of the same. For this purpose we used a sample consisting of ten subjects, all female, with an average age of 11.6 ± 1.35, practicing rhythmic gymnastics. The subjects performed a series of three consecutive counter movement jumps on force platform on the ground, repeating the same procedure in the water. To conduct the experiment was used the technique of kinemetry measuring the angle of the knees push-up and height of the jump and a platform for measuring the strength of the forces of ground vertical reaction. The results were analyzed by the Pearson’s correlation, with a significance level of 5%. The results obtained showed that the jump in running time to reach the aquatic environment, average speed and time of flight were higher and the force of impact on lower limbs, compared with the results in the ground. This work should serve as basis for the development of training programs involving the jump in water and ground, as in activities of plyometric. New research should be carried out using a method of population practicing sports that has the vertical jump as a primary action for the good performance in implementing the same.

Foram estudados os efeitos da metilprednisolona na traquéia de coelhas albinas adultas da raça Nova Zelândia. O objetivo deste estudo foi investigar os efeitos potenciais desta substância nas propriedades biomecânicas da traquéia de coelhas por meio de ensaio de tração axial. Os animais foram divididos em dois grupos. Dez coelhas do grupo controle receberam por via subcutânea 2 mg/Kg/dia de metilprednisolona diluída em solução salina. As dez coelhas do grupo controle receberam também de modo subcutâneo volumes proporcionais de solução salina. Após 21 dias, os animais foram sacrificados e suas traquéias submetidas a ensaio de tração e estudo histopatológico. Os animais do grupo experimental apresentaram peso significantemente inferior ao do grupo controle no final do tratamento (C = 3996 ± 314 g x E = 3555 ± 373 g). Os grupos não diferiram do ponto de vista estatístico quanto as seguintes variáveis: carga no limite de proporcionalidade (C = 8,94 ± 1,68 N x E = 8,93 ± 1,52 N); carga máxima (C = 9,12 ± 2,2 N x E = 9,57 ± 1,90 N); alongamento no limite de proporcionalidade (C = (683 ± 2,08) x '10 POT.-3' m x E = (6,05 ± 1,50) x '10 POT.-3' m); alongamento máximo (C = (7,44 ± 2,60) x '10 POT.-3' m x E = (6,85 ± 1,55) x '10 POT.-3' m); energia absorvida na fase elástica (C = (28,70 ± 14,43) x '10 POT.-3' J x E = (27,75 ± 11,06) x '10 POT.-3' J); rigidez (C = (1,08 ± 0,41) x '10 POT.-3' N/m x E = (1,2 ± 0,37) x '10 POT.-3' N/m). Concluiu-se ao término deste estudo que não houve alterações morfológicas e biomecânicas das traquéias estudadas, no entanto, os animais do grupo experimental sofreram significante emagrecimento ao final do tratamento, quando comparado ao grupo experimental / The effects of methilprednisolona in the adult’s trachea albinos female rabbits were studied. The goal of this study was examine the potential effects of this armorial traction. The animals were divided in two groups. Ten female rabbits of control group received by way of subcutaneous 2mg/kg/day of salt bed diluted solution. These ten female rabbits of the control group also received by way of subcutaneous proportional volumes of salt bed solution. After 21 days, the animals were sacrificed and their trachea were subjected to traction tests and anatomical pathological studies. Animals of the experimental group presented inferior weight significant from the control group in the end of the treatment (C = 8,94 ± 314g X E = 3555 ± 373g). The groups didn’t differ from the statistic point of view as regards of the following variables: limit load of proportionality (C = 8,94 ± 1,68 N X E = 8,93 ± 1,52 N); maxim load (C = 9,12 ± 2,2 N X E = 9,57 ± 1,90 N); stretch out on the limit of proportionality (C = (683 ± 2,08) x '10 POT.-3' m X E = (6,05 ± 1,50) x '10 POT.-3' m); maxim stretch out (C = (7,44 ± 2,60) x '10 POT.-3' J X E = (6,85 ± 1,55) x '10 POT.-3' J); absorbed energy in the elastic phase (C = 28,70 ± 14,43) x '10 POT.-3' m J X E = (27,75 ± 11,06) x '10 POT.-3' J); rigidity (C = 1,08 ± 0,41) x '10 POT.-3' N/m X E = (1,2 + 0,37) x '10 POT.-3' N/m). It was concluded in the end of the treatment that there weren’t any morphological and biomechanical alterations of the trachea studied, although, the animals of the experimental group suffered a significant slimming in the end of the treatment when compared with the experimental group