Dissertations / Theses on the topic 'Applied biomechanics'

Abdominal aortic aneurysms (AAA) occurs due to local enlargement of the abdominal aorta and affects about 1-2 % of the elderly Swedish population. At admission, AAA patients receive a Computed Tomography-Angiography (CT-A) scanning, and later they are followed-up by 2D ultrasound examinations. There is a need to know if an adequate geometry can be constructed from the baseline CT-A scan and follow-up 2D ultrasounds. To test our hypothesis only CT-A images have been used from six patients and hypothetical ultrasound cross-sections (HUCS) were extracted from the follow-up CT-A scans. The baseline AAA surface was expanded in a mechanical model by applying pressure inside of it until it reached the HUCS. The obtained morphed geometries were then compared with the CT-A-based geometries. The discrepancy between them were calculated by distance measurements. Also, the rupture risk indicators volumes and stresses were compared. Finally, a sensitivity analysis studied the effect of HUCS positioning on the volumes and stresses. The results show that an adequate geometry can be constructed by the investigated concept of morphing. The average distances between the morphed and CT-A-based geometries are 2-4 mm. The average volume difference for the six patients are between 3.8-16.2 %. The wall stress for the morphed and CT-A-based geometries are close only for the first follow-up.
Bukaortaaneurysm (AAA) uppstår på grund av lokal förstoring av bukaortan och drabbar 1-2 % av den äldre svenska befolkningen. Vid antagning får bukaortaaneurysm-patienterna en datortomografscanning (CT-A) och senare påföljs av 2D ultraljudsscanningar. Det finns ett behov att veta om en adekvat geometri kan konstrueras från datortomografiscanningen och 2D ultraljudsbilderna. För att testa vår hypotes har endast datortomografibilder från sex patienter använts med hypotetiska ultraljudstvärsnitt (HUCS) tagna från CT-A uppföljningarna. AAA-ytan vid baslinjen expanderades i en strukturmekanisk modell genom inre övertryck tills den nådde de hypotetiska ultraljudstvärsnitten. Därefter jämfördes de morfade geometrierna med de CT-A-baserade geometrierna. Geometriavvikelsen mellan de beräknades genom avståndsmätningar. Även, rupturriskindikatorerna volymer och spänningar jämfördes. Slutligen, genom en känslighetsanalys undersöktes effekten av positioneringen av hypotetiska ultraljudstvärsnitten på volymerna och spänningarna. Resultaten visar att en adekvat geometri kan konstrueras genom den undersökta koncepten av morfning. De genomsnittliga avstånden mellan de morfade och CT-A-baserade geometrierna är 2-4 mm. Genomsnittliga volymskillnaderna för de sex patienterna är mellan 3.8-16.2 %. Väggspänningarna för de morfade och CT-A-baserade geometrierna är nära enbart för den första uppföljningen.

In this thesis, a fully Lagrangian approach called the Discrete Multi-Physics is adopted and applied to biomechanics. The Discrete Multi-Physics combines the Smoothed Particle Hydrodynamics, the Mass and Spring Model and the Discrete Element Method in a common particle-based framework. In the Discrete Multi-Physics, high deformations and contact of solid structures (e.g. valve’s leaflets during closing phase or colloid contact) can be easily modelled. In biological valve simulations, for instance, we were able to account for repeated opening-closing cycles and to introduce an agglomeration algorithm to model clotting. Besides cardiovascular and venous flows, we also applied the Discrete Multi-Physics to respiratory tracts for modelling (i) cilia motion and drug diffusion in the periciliary layer (ciliated epithelium) and (ii) the release of active ingredients in powder inhalers for drug delivery in the lungs.

Why copy the best athletes? When you finally learn their technique, they may have already moved on. Using muscluloskeletal biomechanics you might be able to add the "know-why" so that you can lead, instead of being left in the swells. This dissertation presents the theoretical framework of musculoskeletal modeling using inverse dynamics with static optimization. It explores some of the possibilities and limitations of musculoskeletal biomechanics in cross-country skiing, especially double-poling. The basic path of the implementation is shown and discussed, e.g. the issue of muscle model choice. From that discussion it is concluded that muscle contraction dynamics is needed to estimate individual muscle function in double-poling. Several computer simulation models, using The Anybody Modeling System™, have been created to study different cross-country skiing applications. One of the applied studies showed that the musculoskeletal system is not a collection of discrete uncoupled parts because kinematic differences in the lower leg region caused kinetic differences in the other end of the body. An implication of the results is that the kinematics and kinetics of the whole body probably are important when studying skill and performance in sports. Another one of the applied studies showed how leg utilisation may affect skiing efficiency and performance in double-poling ergometry. Skiing efficiency was defined as skiing work divided by metabolic muscle work, performance was defined as forward impulse. A higher utilization of the lower-body increased the performance, but decreased the skiing efficiency. The results display the potential of musculoskeletal biomechanics for skiing efficiency estimations. The subject of muscle decomposition is also studied. It is shown both analytically and with numerical simulations that muscle force estimates may be affected by muscle decomposition depending on the muscle recruitment criteria. Moreover, it is shown that proper choices of force normalization factors may overcome this issue. Such factors are presented for two types of muscle recruitment criteria. To sum up, there are still much to do regarding both the theoretical aspects as well as the practical implementations before predictions on one individual skier can be made with any certainty. But hopefully, this disseration somewhat furthers the fundamental mechanistic understanding of cross-country skiing, and shows that musculoskeletal biomechanics will be a useful complement to existing experimental methods in sports biomechanics.
Varför ska man kopiera de som är bäst inom sin idrottsgren? När man väl har lärt sig deras teknik så har de antagligen redan gått vidare. Vore det inte bättre att öka sin förståelse så att man kan ligga i framkant, istället för i svallvågorna? Med biomekaniska simuleringar som ett komplement till traditionella experimentella metoder finns möjligheten att få veta varför prestationen ökar, inte bara hur man ska göra för att öka sin prestation. Längdskidåkning innehåller snabba och kraftfulla helkroppsrörelser och därför behövs en beräkningsmetod som kan hantera helkroppsmodeller med många muskler. Avhandlingen presenterar flera muskeloskelettära simuleringsmodeller skapade i The AnyBody Modeling System™ och är baserade på inversdynamik och statisk optimering. Denna metod tillåter helkroppsmodeller med hundratals muskler och stelkroppssegment av de flesta kroppsdelarna. Avhandlingen visar att biomekaniska simuleringar kan användas som komplement till mer traditionella experimentella metoder vid biomekaniska studier av längdskidåkning. Exempelvis går det att förutsäga muskelaktiviteten för en viss rörelse och belastning på kroppen. Detta nyttjas för att studera verkningsgrad och prestation inom dubbelstakning. Utifrån experiment skapas olika simuleringsmodeller. Dessa modeller beskriver olika varianter (eller stilar) av dubbelstakning, alltifrån klassisk stil med relativt raka ben och kraftig fällning av överkroppen till en mer modern stil där åkaren går upp på tå och använder sig av en kraftig knäböj. Resultaten visar först och främst att ur verkningsgradsynpunkt är den klassiska stilen att föredra då den ger mest framåtdrivande arbete per utfört kroppsarbete, dvs den är energisnål. Men ska en längdlöpare komma så fort fram som möjligt (utan att bry sig om energiåtgång) verkar det som en mer modern stil är att föredra. Denna studie visar också att för att kunna jämföra kroppens energiåtgång för skelettmusklernas arbete mellan olika rörelser så krävs det en modell där muskler ingår. Andra studier som presenteras är hur muskelantagonister kan hittas, hur lastfördelningen mellan muskler eller muskelgrupper förändras när rörelsen förändras samt effekter av benproteser på energiåtgång. Några aspekter av metoden presenteras också. Två muskelmodeller och dess inverkan på olika simuleringsresultat visas. En annan aspekt är hur muskeldekomposition och muskelrekryteringskriterium påverkar beräkningarna. Normaliseringsfaktorer för olika muskelrekryteringskriterium presenteras.
Beräkningsbaserad biomekanik inom längdskidåkningen - möjligheter och begränsningar

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.

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 R ³. The Euler-Lagrange equations form three coupled linear partial differential equations with Dirichlet boundary conditions characterizing the buckling displacement field under equilibrium.

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.

Table tennis playing involves complex spatial movement of the racket and human body. It takes much effort for the novice players to better mimic expert players. The evaluation of motion patterns during table tennis training, which is usually achieved by coaches, is important for novice trainees to improve faster. However, traditional coaching relies heavily on coaches qualitative observation and subjective evaluation. While past literature shows considerable potential in applying biomechanical analysis and classification for motion pattern assessment to improve novice table tennis players, little published work was found on table tennis biomechanics. To attempt to overcome the problems and fill the gaps, this research aims to quantify the movement of table tennis strokes, to identify the motion pattern differences between experts and novices, and to develop a model for automatic evaluation of the motion quality for an individual. Firstly, a novel method for comprehensive quantification and measurement of the kinematic motion of racket and human body is proposed. In addition, a novel method based on racket centre velocity profile is proposed to segment and normalize the motion data. Secondly, a controlled experiment was conducted to collect motion data of expert and novice players during forehand strokes. Statistical analysis was performed to determine the motion differences between the expert and the novice groups. The experts exhibited significantly different motion patterns with faster racket centre velocity and smaller racket plane angle, different standing posture and joint angular velocity, etc. Lastly, a support vector machine (SVM) classification technique was employed to build a model for motion pattern evaluation. The model development was based on experimental data with different feature selection methods and SVM kernels to achieve the best performance (F1 score) through cross-validated and Nelder-Mead method. Results showed that the SVM classification model exhibited good performance with an average model performance above 90% in distinguishing the stroke motion between expert and novice players. This research helps to better understand the biomechanical mechanisms of table tennis strokes, which will ultimately aid the improvement of novice players. The phase segmentation and normalization methods for table tennis strokes are novel, unambiguous and straightforward to apply. The quantitative comparison identified the comprehensive differences in motion between experts and novice players for racket and human body in continuous phase time, which is a novel contribution. The proposed classification model shows potential in the application of SVM to table tennis biomechanics and can be exploited for automatic coaching.

We address outflow boundary conditions for blood flow modeling. In particular, we consider a variety of fundamental issues in the structured tree boundary condition. We provide a theoretical analysis of the numerical implementation of the structured tree, showing that it is sensible but must be performed with great care. We also perform analytical and numerical studies on the sensitivity of model output on the structured tree's defining geometrical parameters. The most important component of this dissertation is the derivation of the new, generalized structured tree boundary condition. Unlike the original structured tree condition, the generalized structured tree does not contain a temporal periodicity assumption and is thus applicable to a much broader class of blood flow simulations. We describe a numerical implementation of this new boundary condition and show that the original structured tree is in fact a rough approximation of the new, generalized condition.

We also investigate parameter selection for outflow boundary conditions, and attempt to determine a set of structured tree parameters that gives reasonable simulation results without requiring any calibration. We are successful in doing so for a simulation of the systemic arterial tree, but the same parameter set yields physiologically unreasonable results in simulations of the Circle of Willis. Finally, we investigate the extension of recently introduced PDF methods to smooth solutions of systems of hyperbolic balance laws subject to uncertain inputs. These methods, currently available only for scalar equations, would provide a powerful tool for quantifying uncertainty in predictions of blood flow and other phenomena governed by first order hyperbolic systems.

The objectives of this study were to (1) develop a non-invasive method (referred to as Smart Photo-Tape) to calculate participant-specific upper arm, forearm, and hand segment inertial properties (SIPs) (e.g. mass, center of mass, and radii of gyration) and (2) use those Smart Photo-Tape properties in inverse dynamics (ID) analyses to calculate injury-related pitching arm kinetics. Five 20- to 23- year-old baseball pitchers were photographed holding a baseball and analyzed using the Smart Photo-Tape method to obtain 3-D inertial properties for their upper arm, forearm, and hand. The upper arm and forearm segments were modelled as stacked elliptic cylinders and the hand was modelled as an ellipsoid. One participant received a dual energy x-ray absorptiometry (DXA) scan and conducted a motion analysis study, pitching 10 fastballs. Scaled SIPs from cadaver studies and Smart Photo-Tape SIPs were compared using one sample t-tests. Pitching arm kinetic predictions were calculated and compared using scaled inverse dynamics (ID), Smart Hand ID (a combination of scaled SIPs for the upper arm and forearm and Smart Photo-Tape SIPs for the hand), and Smart Photo-Tape ID. The major result was that the Smart Photo-Tape SIPs were significantly different when compared to their respective scaled inertial properties, with the hand segment producing the largest difference between the scaled SIPs and Smart Photo-Tape SIPs. The implication of this study is that researches or coaches can use the Smart Photo-Tape method to calculate participant specific SIPs for pitching arm kinetic analysis.

Orientador: Fausto Bérzin
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
Made available in DSpace on 2018-08-21T20:25:06Z (GMT). No. of bitstreams: 1 CarranzaLopez_CarlosAlberto_M.pdf: 2138268 bytes, checksum: a9443199a187ae6526690dda5e8b63fe (MD5) Previous issue date: 2012
Resumo: O osso hioide é um osso em forma de U que não se articula com nenhum outro osso, se localiza na parte anterior do pescoço e participa em funções importantes como deglutição, fala, mastigação e respiração. Para se manter estável, o osso hioide está suspenso por ligamentos, fascias e músculos. Diversos estudos em pessoas sem problemas dentários, esqueléticos nem funcionais demonstraram que o osso hioide localiza-se numa posição mais inferir nos homens que nas mulheres, mas nem sempre em todos os homens está nesta posição. O objetivo deste trabalho foi determinar se a posição do osso hioide tem relação com a atividade eletromiografica dos músculos supra-hioideos e infra-hioideos. Foram selecionados voluntariamente 16 homens classe I esquelética, sem problemas de disfunção temporomandibular, sem problemas visuais ou de respiração oral. Para avaliar a posição do osso hiode foram tomadas radiografias laterais em posição natural da cabeça de todos os voluntários e foi avaliado o triângulo hioideo. Para determinar a posição vertical do osso hióde, considerou-se a altura do triângulo hióide, valores menores a 3,4 mm foi considerado como posição superior do osso hioide (Grupo HS) e valores maiores a 4,6 mm como posição inferior do osso (Grupo HI). A atividade dos músculos supra-hioideos e infra-hioideos foi avaliada por meio da eletromiografia nas seguintes condições: repouso, isometria, protrusão, ápice da língua sobre o palato mole e deglutição. A comparação da raiz média quadrada (RMS) entre os grupos mostrou diferença significativa apenas para o movimento de protrusão. Este resultado poderia indicar uma maior sensibilidade dos fusos neuromusculares dos músculos supra-hioideos frente ao alongamento no grupo HS. Conclui-se que o os voluntários que tem o osso hioide numa posição superior apresentaram maior atividade dos músculos supra-hioide quando realizaram o movimento de protrusão
Abstract: The hyoid bone is a U-shaped bone and does not articulate with any other bone. He is located in front of the neck and participates in important functions such as swallowing, speaking, chewing and breathing. To remains stable, he is suspended by ligaments, fascia and muscles, as supra-hyoid and hyoid infra-hyoid muscles. Several studies in people without dental, skeletal or functional problems showed that hyoid bone is located in a lower position in men than in women, but not always he is in this position in all men. The aim of this study was to determine if the position of the hyoid bone interfere in electromyography activity of the supra hyoid and infra hyoid muscles. We selected voluntarily, 16 men skeletal Class I, without DTM, visual or mouth breathing problems. To assess the hyoid bone position were taken lateral radiographs of all volunteers and was assessed the hyoid triangle, too. To determine the vertical position of hyoid bone, it was considered the height of the hyoid triangle; values less than 3.4 was considered as upper position of the hyoid bone (Group UH) and values greater than 4.6 as lower position of the hyoid bone (Group LH). The activity of the supra hyoid and infra hyoid muscles were assessed by electromyography in following conditions: rest, isometrics, protrusion, tongue tip on the soft palate and swallowing. The comparison of the root mean square (RMS) between the groups showed a significant difference only for the movement of protrusion. This result could indicate a greater sensitivity of the neuromuscular spindles of supra hyoid muscles. We concluded that the volunteers that have upper position of hyoid bone showed higher activity of supra hyoid muscle when performed the protrusion movement
Mestrado
Anatomia
Mestre em Biologia Buco-Dental

Recently, a constituent based cartilage growth finite element model (CGFEM) was developed in order to predict articular cartilage (AC) biomechanical properties before and after growth. Previous research has noted limitations in the CGFEM such as model convergence with growth periods greater than 12 days. The main aims of this work were to address these limitations through (1) implementation of an exact material Jacobian matrix definition using the Jaumann-Kirchhoff (J-K) method and (2) quantification of elastic material parameters based upon research findings of the Cal Poly Cartilage Biomechanics Group (CPGBG). The J-K method was successfully implemented into the CGFEM and exceeded the maximum convergence strains for both the “pushed forward, then differentiated” (PFD) and “differentiated, then pushed forward” (DPF) methods, while maintaining correct material stress responses. Elastic parameters were optimized for confined compression (CC), unconfined compression (UCC), and uniaxial tension (UT) protocols. This work increases the robustness of the CGFEM through the J-K method, as well as defines an accurate starting point for AC growth based on the optimized material parameters.

Bilateral mandibular ostectomies were performed between premolars 3 and 4 in 10 adult canine specimens. A type I external fixator incorporating a full interdental pin was placed stabilizing a 0.5 cm fracture gap. Four different pin configurations were tested in dorsoventral bending five separate times on each of the ten mandibles: 1) intact mandibular bodies with fixator; 2) ostectomized mandibular bodies and complete fixator; 3) ostectomized mandibular bodies with the caudal pins of the rostral fragment cut; 4) ostectomized mandibular bodies with all pins of the rostral fragment cut. The full interdental pin remained intact in all configurations. Total stiffness and gap stiffness were then determined for each fixation geometry on a materials testing machine. The mean total stiffness(Nm/rads) for the four configurations was 1) 1543.6, 2) 301.6, 3) 290.5, 4) 267.0. The mean gap stiffness(Nm/rads) for the right hemimandible was: 2) 2041.1, 3) 1763.5, 4) 1679.9. The mean gap stiffness of the left hemimandible was: 2) 2110.8, 3)1880.1, 4)1861.1. There was no gap stiffness for the first configuration since a fracture gap was not present. Two-way ANOVA was performed on the gap stiffness and the total stiffness. There was a significant decrease in total stiffness between intact mandibles and ostectomized mandibles regardless of external fixator configuration. However, there was not a significant difference in total stiffness or gap stiffness among the different external fixator configurations applied to ostectomized mandible. External fixator configurations with only the full interdental pin engaging the rostral fragment were as stiff as configurations which had two or four additional pins in the rostral fragment for the applied loads. External fixators for rostral mandibular fractures may be rigidly secured with rostral fragment implants applied extracortically avoiding iatrogenic trauma to teeth and tooth roots.
Master of Science

Experimental results show that collagen fibers exhibit stress relaxation under tension and a highly anisotropic distribution. To further develop the earlier model of Stender [1], the collagen constituent was updated to reflect its intrinsic viscoelasticity and anisotropic distribution, and integrated with an existing mixture model with glycosaminoglycans and ground substance matrix. A two-term Prony series expansion of the quasi-linear viscoelastic model was chosen to model the viscoelastic properties of the collagen fibers. Material parameters were determined by using the simplex method to minimize the sum of squared errors between model results and experimental stress relaxation data of tissue in tension. Collagen elastic fiber modulus was calculated by fitting to the equilibrium data and viscoelastic parameters were determined by fitting to the relaxation curve. Results of newborn (~1-3 week old) untreated bovine articular cartilage explants from the patellar femoral groove as well as explants cultured in transforming growth factor-β1 (TGF-β1), from both the superficial (~0-0.5 mm from the articular surface) and middle (~0.5-1.0 mm from the articular surface) layers were compared to examine the effects of TGF- β1. TGF-β1 has been shown to maintain or even enhance mechanical properties of articular cartilage in compression and tension [2, 3] and this study continues with the hope that it may be used to improve tissue engineering of mature cartilage to better survive implantation in vivo for the successful repair of articular cartilage defects. Results show that TGF-β1 has a maturational effect on collagen, causing the tissue to become stiffer through an increase in elastic collagen fiber modulus and less viscous through shorter relaxation time and less stress relaxation (tissue retained a higher percentage of residual stress). The results of this study further advance the understanding of the effects of location and treatment with TGF-β1.

The aorta, the main and largest artery in the human body, is susceptible for many types of problems. One of the most common aortic disease is the formation of an aneurysm. Endovascular aortic aneurysm repair (EVAR) is a minimally invasive treatment option for aortic aneurysms, involving the deployment of an expandable stent graft within the aorta without operating the aneurysm directly. With 1.5 to 43 % of EVAR patients having postoperative complications, research to help predict these complications of EVAR is of essence. In this study, the deformations of the aorta induced by a deployed stent graft have been investigated and visualized in order to aid understanding of the geometrical behaviour of the aorta post EVAR. This has been carried out by the development and analysis of patient-specific aortic 3D reconstruction models, 3D printed physical models and FE simulation models. A qualitative assessment of the deformations was achieved by superimposing reconstructed geometries, revealing a light straightening of the aorta and iliac vessels, as well as anterior movement of the iliac branches. Based on the good agreement between the simulated and reconstructed geometries, the findings suggest that such deformations could be derived from the pressure being removed from the aneurysm due to the deployed stent graft, in combination with stent radial forces from the proximal and distal landing zones. Despite that the simulation seemed to underestimate distal movement of the iliac vessel, this study emphasizes the potential of 3D printing and FE analysis as promising tools for planning and research of EVAR.
Den stora kroppspulsådern, aortan, kan drabbas av flera olika sjukdomstillstånd. En av de vanligaste är bildandet av en aortaaneurysm. Endovaskulär Aneruysm Reparation (EVAR) är en operationsteknik för att behandla aortaaneurysmer och involverar positionering av ett rörformat, självexpanderande stentgraft innanför aortaaneurysmen via ljumskartärerna. Eftersom 1,5 till 43 % av EVAR-patienter råkar ut för postoperativa komplikationer är det väsentligt att bedriva vidare studier för att förutse dessa. I denna studie har deformationerna av en aorta på grund av positionerade stentar undersökts och visualiserade för att underlätta förståelsen av aortans geometriska beteende efter EVAR. Detta har gjorts genom att utveckla och analysera patientspecifika 3D-rekonstruktioner, 3D-printade fysiska modeller och simulerade modeller av en aorta. En kvalitativ bedömning av deformationerna uppnåddes genom att superpositionering av rekonstruerade geometrier, vilket avslöjade en lätt uträtning av aortan och tarmbensartärerna, samt en framförflyttning av de senare. Baserat på den goda överensstämmelsen mellan de simulerade och rekonstruerade modellerna, antyder resultaten att sådana deformationer kan härledas av att trycket avlägsnats från aneurysmen på grund av stentgraften, i kombination med radiellt tryck från stentar över och under aneurysmen. Trots att simuleringen underskattade framförflyttningen av tarmbensartärerna, belyser denna studie potentialen hos 3D-printing och FE-analyser som ett värdefullt verktyg för att planera och studera EVAR.

La maladie de Kienböck fragilise le lunatum, qui souvent évolue vers la fracture et le collapsus. Divers facteurs ont été évoqués pour en expliquer l’origine, principalement anatomiques, comme l’index radio-ulnaire distal négatif, la structure trabéculaire du lunatum ou la pente de la glène radiale. Le carpe est soumis à des forces de compression qui tendent à le disloquer ou à l’écraser. Cette compression transmise par les métacarpiens se concentre dans le carpe vers l’espace radio-scapho-lunaire.La prise en charge chirurgicale la plus courante de la maladie de Kienböck avant le collapsus arthrosique est la décompression du lunatum par raccourcissement osseux de voisinage. Si l'ostéotomie transversale de raccourcissement du radius est la plus répandue, d’autres ostéotomies ont été proposées: l'ostéotomie de soustraction externe du radius, de soustraction interne du radius, d’accourcissement du capitatum, parfois étendue à l’hamatum. Ces différentes ostéotomies ayant un résultat différent sur l’anatomie, on peut supposer un effet de décompression variable sur le lunatum.Notre point de vue est que pour éviter la fracture du lunatum, il faut le soustraire durablement aux contraintes, en les déviant vers le scaphoïde ou le triquetrum. L’espace radio-scaphoïdien paraît moins à risque de conflit par hyperpression que l’espace ulno-carpien. Notre hypothèse est que pour dévier les contraintes vers le scaphoïde, il ne faut pas que le raccourcissement concerne la colonne externe du carpe, et l’espace radio-scaphoïdien. Nous avons envisagé de planifier une ostéotomie du radius pour ne pas décomprimer le scaphoïde. L’ostéotomie “Camembert” consiste à réséquer un coin osseux délimité entre le bord ulnaire du radius et le centre de la glène radiale.La technique est réalisée par voie dorsale, avec une résection contrôlée sous ampli, et une ostéosynthèse par une agrafe. Les résultats sont rapportés sur une série de 11 poignets opérés à sept ans de recul. Ils sont excellents et bons dans huit cas, corrects dans 2 cas, et mauvais une fois.Nous avons mené une analyse biomécanique par éléments finis, comparant la décompression du lunatum suivant différentes ostéotomies. Certaines ostéotomies peuvent entraîner une surcharge du lunatum, une surcharge au niveau de la STT avec hyperflexion scaphoïdienne, ou une surcharge ulno-carpienne, possiblement péjoratives. L'ostéotomie Camembert semble éviter ces écueils. Combinée à une ostéotomie ulnaire de Sennwald, que nous proposons lorsque la variance du cubitus est neutre ou positive, elle semble être celle qui décomprime le mieux le lunatum. La voie d’abord postérieure préserve la vascularisation palmaire du radius accompagnant le muscle carré pronateur. Elle ne nécessite pas d’incision de la capsule radiocarpienne, au contraire de l’ostéotomie du capitatum, ce qui préserve la vascularisation et les ligaments stabilisateurs du carpe. Nous proposons d'utiliser cette procédure pour les stades Lichtman 1-2-3A s'il n'y a pas de lésions du cartilage ou des ligaments, ce qui peut être vérifié au mieux par arthroscopie avant de confirmer l’indication.
Kienböck's disease weakens the lunate, which often evolves to fracture and collapse. Various factors, mainly anatomical, have been suggested to explain its origin, such as the negative distal radioulnar index, the trabecular structure of the lunate or the slope of the radial glenoid. The carpus is subjected to compressive loads that tend to dislocate or collapse it. This load transmitted by the metacarpals is concentrated through the carpus towards the radio-scapho-lunate space.The most common surgical management of Kienböck's disease prior to osteoarthritic collapse is decompression of the lunate by neighbourhood bone shortening. While transverse osteotomy for radius shortening is the most common, other osteotomies have been proposed: lateral radius shortening osteotomy, medial radius shortening osteotomy, capitate shortening, sometimes extended to the hamate. As these different osteotomies have a different result on the anatomy, a variable unloading effect of the lunate can be assumed.Our point of view is that to avoid a lunate fracture, it must be durably relieved from stresses by diverting it towards the scaphoid or the triquetrum. The radio-scaphoid space seems less at risk of hyperpressure than the ulno-carpal space. Our hypothesis is that to deviate the stresses towards the scaphoid, the shortening must involve neither the external column of the carpus, nor the radius facing the scaphoid. The "Camembert" osteotomy consists in resecting a bone wedge delimited between the ulnar edge of the radius and the centre of the radial glenoid.The technique is performed dorsally, with controlled bone resection under fluoroscopy. Osteosynthesis is completed with a staple. The results are reported on a series of 11 wrists with seven years follow-up. They are excellent and good in 8 cases, correct in 2 cases, and bad once.We conducted a biomechanical finite element analysis comparing the decompression of the lunate following different osteotomies. Some osteotomies may result in lunate overload, STT overload with scaphoid hyperflexion, or ulnocarpal overload, possibly pejorative. The Camembert osteotomy seems to avoid these pitfalls. Combined with a Sennwald ulnar osteotomy, notably when the ulnar index is neutral or positive, it seems to be the one that best unloads the lunate. The posterior approach preserves the palmar vascularization of the radius accompanying the pronator quadratus muscle. It does not require any incision of the dorsal radiocarpal capsule, unlike the capitate shortening, which preserves the vascularization and stabilizing ligaments of the carpus. We propose to use Camembert osteotomy for Lichtman 1-2-3A stages if there is no cartilage or ligament damage, which can best be verified arthroscopically before confirming the indication.
Doctorat en Sciences médicales (Médecine)
info:eu-repo/semantics/nonPublished

Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2007.
Includes bibliographical references.
The North Atlantic right whale, Eubalaena glacialis, one of the most critically endangered whales in the world, is subject to high anthropogenic mortality. Vessel-whale collisions and entanglement in fishing gear were indicated in 27 (67.5%) of the 40 right whales necropsied between 1970 and December 2006. Of those, at least 9 deaths (22.5%) resulted from blunt contact with a vessel. To reduce the likelihood of fatal collisions, speed restrictions are being considered for vessels traversing critical habitat, although the effects of speed on collision outcomes have not been specifically evaluated from a biomechanics perspective. The ultimate goal of a larger collaborative project is to evaluate the efficacy of speed restrictions for reducing blunt collision mortality using a multi-scale finite element model. Complete, transverse fracture of the right whale mandible, an injury seen only in right whales killed by vessels, is used as a proxy for mortality in the model. Vital for that model are the material properties and biomechanical behavior of the right whale mandible. Here, the internal structure and physical properties of right whale jawbone tissue are reported. The average apparent densities, 0.4258 g/cc ±0.0970 and 1.2370 g/cc ±0.0535 for trabecular and cortical bone respectively, indicate that the bone is of relatively low density. Average ash content for trabecular bone (64.38% ±1.1330) is comparable with values from other species, indicating that low density results from a reduction of bone mass, not mineralization. Mechanical properties of right whale bone (Young's modulus of elasticity and Poisson's ratio) were determined via uniaxial compression testing.
(cont.) These data are incorporated into the finite element model simulating different loading conditions (e.g. vessel speeds) that likely lead to mandibular failure and thereby mortality from blunt vessel collisions. Model results (e.g. risk of fracture) are used to determine the effect of speed restrictions on collision outcomes.
by Regina Campbell-Malone.
Ph.D.

Mesenchymal stem cells (MSCs) may benefit vascular cell-based therapies as smooth muscle or endothelial cell substitutes or through paracrine actions to repair, replace, or regenerate vascular tissue. Previous studies have demonstrated that MSCs can adopt traits of smooth muscle cells (SMCs) or endothelial cells (ECs), as well as secrete specific factors that tune signaling and material properties in the local environment. Few studies have investigated the cell signaling response of MSCs to mechanical forces present in the vasculature: specifically, shear stress due to blood flow and cyclic strain due to pulsatile blood flow. Thus, the central objective of this dissertation was to determine the signaling responses of MSCs to vascular-relevant applied physical forces, in comparison with that of differentiated vascular cells. Vascular-relevant mechanosignaling of MSCs was assessed through two comparisons: (1) MSC and SMC responses to applied cyclic strain and (2) MSC and EC responses to applied fluid shear stress. MSCs and SMCs were seeded on fibronectin-coated silicone and subjected in vitro to cyclic strain (10%, 1 Hz) or parallel static culture using a custom-built equibiaxial cyclic strain device. Gene expression analysis of 84 signal transduction molecules demonstrated both cell types respond with significant (p<0.05, n=3) fold-changes (|FC|≥ 1.5) within 24 hours of applied equibiaxial strain. Most strain-responsive genes identified were significantly strain-responsive in only one cell type. A signaling trio of Interleukin 8, Vascular cell adhesion molecule 1, and Heme oxygenase 1 was significantly altered in both MSCs and SMCs, suggesting cyclic strain regulates immune and inflammatory functions in both cell types. The response to shear stress of MSCs and ECs was compared using cells seeded on type I collagen or fibronectin and exposed to steady laminar shear stress (5 or 15 dyn/sq-cm) using a parallel plate shear chamber system. Gene expression was compared in MSCs and ECs for a panel of immune and inflammation-related markers. Expression of Cox-2 and Hmox-1 increased significantly (p<0.05, n≥3; |FC|≥1:5) in both cell types. Reduced shear stress-responses of Mcp-1, Pecam-1, and VE-Cad in MSCs relative to ECs suggests that MSCs promote less inflammation and immune activation in response to shear stress than ECs. Mechanosensitivity profiles for MSCs and differentiated vascular cells were broadened using whole genome microarrays. These high-throughput studies confirmed that (1) signaling profiles between sample groups vary significantly more (p<0.05, n=3) with cell type than applied force condition and (2) a subset of conserved mechanosensitive genes alter expression levels significantly and in the same direction fold-change in multiple cell types. Bioinformatics analysis of these conserved mechanoresponsive genes highlighted oxidative stress, cell cycle, and DNA replication as functions regulated by vascular-relevant mechanical cues. These studies demonstrate that MSCs partially reproduce differentiated vascular cell mechanosignaling, while simultaneously altering expression of genes not typically force-responsive in vascular cells. This work defines a role for conserved mechanosignals, based on genes whose expression in response to applied force alters significantly (p<0.05, n≥3) and by at least 1.5-fold change in multiple cell types and/or force types. Comparisons completed for this dissertation motivate future studies to track the functional impact of specific similar or unique MSC mechanoresponses. This work contributes to design of MSC-based vascular therapies and an understanding of stem and differentiated cell mechanobiology.

Statistical data from clinical studies indicate that the death rate caused by heart disease has decreased due to an increased use of evidence-based medical therapies. This includes the use of magnetic resonance imaging (MRI), which is one of the most common non-invasive approaches in evidence-based health care research. In the current work, I present 3D Lagrangian strains and torsion in the left ventricle of healthy and isoproterenol-stimulated rats, which were investigated using Displacement ENcoding with Stimulated Echoes (DENSE) cardiac magnetic resonance (CMR) imaging. With the implementation of the 12-segment model, a detailed profile of regional cardiac mechanics was reconstructed for each subject. Statistical analysis revealed that isoproterenol induced a significant change in the strains and torsion in certain regions at the mid-ventricle level. In addition, I investigated right ventricular cardiac mechanics with the methodologies developed for the left ventricle. This included a comparison of different regions within the basal and mid-ventricular regions. Despite no regional variation found in the peak circumferential strain, the peak longitudinal strain exhibited regional variation at the anterior side of the RV due to the differences in biventricular torsion, mechanism of RV free wall contraction, and fiber architecture at RV insertions. Future applications of the experimental work presented here include the construction and validation of biventricular finite element models. Specifically, the strains predicted by the models will be statistically compared with experimental strains. In addition, the results of the present study provide an essential reference of RV baseline evaluated with DENSE MRI, a highly objective technique.

This thesis proposes an algorithm that determine the geometry of 3D-printed, custom-designed spring element bands made of thermoplastic elastomer (TPE) for use in a wearable orthotic device to aid in the physical therapy of a human hand exhibiting spasticity after stroke. Each finger of the hand is modeled as a mechanical system consisting of a triple-rod pendulum with nonlinear stiffness at each joint and forces applied at the attachment point of each flexor muscle. The system is assumed quasi-static, which leads to a torque balance between the flexor tendons in the hand, joint stiffness and the design force applied to the fingertip by the 3D-printed spring element. To better understand material properties of the spring element’s material, several tests are performed on TPE specimens printed with different infill geometries, including tensile tests and cyclic loading tests. The data and stress-strain curves for each geometry type are presented, which yield a nonlinear relationship between stress and strain as well as apparent hysteresis. Polynomial curves are used to fit the data, which allows for the band geometry to be designed. A hypothetical hand is presented along with how input measurements might be taken for the algorithm. The inputs are entered into the algorithm, and the geometry of the bands for each finger are generated. Results are discussed, and future work is noted, providing a means for the design of a customized orthotic device.

In der vorliegenden Arbeit wird eine Methodik zur Entwicklung mechanischer Simulationen der Interaktion Sportler-Sportgerät-Umwelt zur Untersuchung der Funktionalität von Sportgeräten konzipiert und vorgestellt. Die mechanische Simulation ist die gegenständliche Nachbildung spezieller Teilaspekte des Sportlers, z.B. der Körperform, der Trägheitseigenschaften, der Masse, der Interaktionskräfte zur Umwelt oder charakteristischer Bewegungsabläufe zum Zweck der Durchführung gezielter Experimente zur Untersuchung des dynamischen Systemverhaltens Sportler-Sportgerät-Umwelt. Dazu werden drei Fallbeispiele aus der Forschungstätigkeit der Arbeitsgruppe HLST an der Technischen Universität Chemnitz mit Methoden zur Verifikation von Simulationsmodellen – dem strukturierten Durchgehen, der Validierung im Dialog und dem Schreibtischtest – analysiert. Die Analyseergebnisse werden in eine Grobstruktur eingebettet, die aus relevanten Vorarbeiten zur Anwendung der Allgemeinen Modelltheorie abgeleitet ist. Die in den jeweiligen Fallbeispielen verwendeten Prozessschritte, Methoden und Werkzeuge werden dargestellt und die Entwicklungsergebnisse erörtert. Im Abschluss jedes Fallbeispiels wird der Entwicklungsprozess anhand von einheitlichen Kriterien bewertet. In einem abschließenden Schritt erfolgt die Zusammenführung der im Stand der Technik dargelegten Grundlagen und der in den drei Fallbeispielen gewonnenen Informationen zu einer strukturieren und kommentierten Methodik
In this dissertation a methodology is conceived that aims to structure the development process of test arrangements that mechanically simulate the interaction of athlete, sports equipment and environment. Mechanical simulation in this context is defined as the physical replication of specific properties of the athlete (e.g. the shape of the human body, body weight, joint kinematics, inertia, external forces in specific movements) in order to conduct experiments to investigate the dynamic behavior of the system athlete-equipment-environment. Therefore, three case studies of mechanical simulation models that have been developed at Technische Universität Chemnitz are analyzed by applying the validation and verification methods “structured walkthrough”, “face validity” and “desk checking”. The results of that analysis are embedded into a framework that is derived by literature review on applied model theory. For each of the three development processes the procedure model is identified and main tools and methods are discussed. Every case study is finally assessed by using standardized evaluation criterions. Finally, the main findings of the analysis of the case studies as well as knowledge obtained by reviewing the state of the art in model theory and simulation methods are used to build up a structured and commentated guideline

Football is a much loved sport in the United States. Unfortunately, it is also hard on the players and puts them at very high risk of concussion. To combat this an inventor in Santa Barbara brought a new design to Cal Poly to be tested. The design was tested in small scale first in order to make some preliminary conclusions about the design. In order to fully test the helmet design; however, full scale testing was required. In order to carry out this testing a drop tower was built based on National Operating Committee on Standards for Athletic Equipment, NOCSAE, specification. The drop tower designed for Cal Poly is a lower cost and highly portable version of the standard NOCSAE design. Using this drop tower and a 3D printed prototype the new design was tested in full scale.

Cette thèse porte sur la modélisation et vérification des signatures en ligne. La première partie a pour thème principal la modélisation biomécanique des mouvements de la main. Un modèle basé sur le critère de Minimum de Secousse (MS) a été choisi parmi plusieurs théories du contrôle moteur. Ensuite, le problème de la segmentation des trajectoires en traits qui correspondent au modèle cinématique choisi a été étudié, ce qui a conduit à la mise au point d'une méthode de segmentation itérative. Le choix du modèle et de la méthode de segmentation sont basé sur le compromis entre la qualité de reconstruction et la compression. Dans la deuxième partie, le modèle polynomial issu du critère de MS est volontairement dégradé. Les zéros non-Réels des polynômes sont jetés et les effets de cette dégradation sont étudiés dans une perspective de vérification biométrique. Cette dégradation est équivalente à la technique connue sous le nom d’Infinity Clipping, initialement appliqué à des signaux de parole. Pour les signatures en ligne, comme pour la parole, la préservation de l'information essentielle a été observée sur des tâches de vérification de signature. En fait, en utilisant seulement la distance de Levenshtein sur la représentation dégradée, un taux d'erreur comparable à ceux des méthodes plus élaborées a été obtenu. En outre, la représentation symbolique issue de l’Infinity Clipping permet d’établir une relation conceptuelle entre le nombre de segments obtenus par la segmentation itératif basée sur le MS et la complexité de Lempel-Ziv. Cette relation est potentiellement utile pour l'analyse des signatures en ligne et pour l’amélioration des systèmes de reconnaissance
This thesis deals with the modelling and verification of online signatures. The first part has as main theme the biomechanical modelling of hand movements associated to the signing gesture. A model based on the Minimum Jerk (MJ) criterion was chosen amongst the several available motor control theories. Next, the problem of signature trajectory segmentation into strokes that better fit the chosen kinematic model is studied, leading to the development of an iterative segmentation method. Both the choice of the model and the segmentation method are strongly based on the tradeoff between reconstruction quality and compression. On the second part, the polynomial model provided by the MJ criterion is intentionally degraded. The non-Real zeroes of the polynomials are discarded and the effects of this degradation are studied from a biometric verification perspective. This degradation is equivalent to the signal processing technique known as Infinity Clipping, originally applied to speech signals. On signatures, as for speech, the preservation of essential information was observed on signature verification tasks. As a matter of fact, using only the Levenshtein distance over the infinitely clipped representation, verification error rates comparable to those of more elaborate methods were obtained. Furthermore, the symbolic representation yielded by the infinity clipping technique allows for a conceptual relationship between the number of polynomial segments obtained through the Minimum Jerk-Based iterative segmentation and the Lempel-Ziv complexity. This relationship is potentially useful for the analysis of online signature signals and the improvement of recognition systems

The common 3-point safety belt usually has some anchor points on the car body. However, it is also possible to mount all anchor points on the seat structure. In general, different studies show some advantages with seat integrated safety belts. Thus, further investigations are motivated. One safety advantage appears in the case of so-called small overlap crashes. Also, the ride-down distance of the occupant may be increased by allowing controlled energy absorbing deformation of the seat structure. Further, methods that can be used to minimize the weight of seat structures with integrated safety belts are of interest. A complement to full scale crash tests is the use of numerical models and numerical simulation, typically finite element (FE) analysis. Research and development of numerical models are constantly improved. In general, any type of numerical model needs to be evaluated to physical tests in order to make it behave as realistic as possible. The purpose of the present thesis was to study seat structures with integrated safety belts with a design that may intentionally deform and absorb energy during a crash. The approach was to use numerical models and numerical simulation and to investigate both biomechanical and mechanical responses. The aim is to create a basis for future research in the design of seat structures with integrated safety belts. In Paper A and B, parametric studies comparing integrated 3- and 4-point safety belt configurations relative to common 3-point configurations are presented. A number of mechanical parameters were varied. Biomechanical responses of the Hybrid III (HIII) FE-dummy model used as occupant were studied. In Paper C, the creation and evaluation of a human FE-model of a 50th percentile male is presented. The evaluation was made to results from studies with post mortem human subjects (PMHS). In Paper D, a conceptual methodology for mass minimization of a property based model (PBM) of a seat structure with an integrated 3-point safety belt configuration and with a HIII FE-dummy model used as occupant is presented. Both mechanical and biomechanical constraints were used as well as different start values of the design variables. In Paper E, the evaluation of FE-models of simplified seat structures with integrated 3-point safety belt configurations to a number of full scale experiments in the form of sled tests with a HIII crash test dummy used as occupant is presented. The studies in Paper A and B reveals that with an adequate combination of mechanical properties of the seat structure it should be possible to achieve equal or lower biomechanical responses of the occupant with a seat integrated safety belt configuration compared to a common. The seat integrated 4-point configurations in these studies performed poorer than the corresponding 3-point in general. An important issue is that belt- webbing distribution between lap and torso belt parts is allowed. The study in Paper C showed that the created and evaluated human FE-model could be used to further explore injury producing mechanisms. However, in order to achieve a fully evaluated human FE-model there is a need for both further development and more reference tests with PMHS. In Paper D, the study showed that the presented methodology may be used in a concept phase of a design process. The optimization runs with different start values of the design variables found a number of different local minima instead of one global minimum. The dynamics of the system was highly non-linear. To find an optimal combination of mechanical properties and biomechanical responses, a compromise appears to be needed. The evaluated FE-model in Paper E may be used in simulations that consider both biomechanical and mechanical responses. The majority of the simulated responses showed good agreement with or slightly underestimated the experimental responses. Some issues of the FE-model suggest areas for further development. The FE-model could be used as a base for further studies.
Godkänd; 2008; 20080404 (ysko)

Globally, approximately 1.2 million people die each year due to traffic accidents. Upper extremity injuries account for 18% to 25% of all car accident injuries. In order to be able to analyze these crash-related injuries, Human body models(HBMs) are used as a complement to FE simulations. An example of a HBM is the THUMS SAFER that is based on a 50 percentile American male. The aim of this study was to improve the upper extremity of the THUMS SAFER with respect to Autoliv's requirements to better predict fractures. In addition, this was validated against the Forman experiment(Forman, et al., The journal of trauma and acute care surgery, vol. 77, 2014) where human cadavers of the upper extremity were axially impacted to replicate a car collision. This was done by generating the upper extremity geometry with segmentation of medical images of a right human hand in combination with the complete STL-geometry of the forearm from the Piper project. The STL-geometry of the segmented human hand and Piper forearm was integrated and a complete STL-geometry of the upper extremity was obtained. Based on the complete STL-geometry, the FE-arm HEX 4.0 was built with modelling of bones, ligaments, soft tissue and skin with corresponding material choice in accordance with Autoliv's requirements. The model HEX 4.0 was improved considering an increased mesh density from an average of 94% to 98%. HEX 4.0 was also validated against the data from the Forman experiment for experiments 5, 6 and 15. It showed a good correlation with the acceleration curves between the simulated and experimental values for the three experiments. The reaction force in the elbow was compared for experiment 15, where the simulated value 5.7 kN divided by a factor of 1.4 from 4 kN for the experiment. Furthermore, the fi rst principal strains that occurred in HEX 4.0 were analysed by 17 ms were the highest acceleration was achieved for experiments 5 and 6. Both experiments were shown to be close to the failure threshold of bones. However, the highest value e5=9.8E-03 occurred in the radius for experiment 5, while e6=9.3E-03 in a ligament for experiment 6. In addition, the failure threshold for experiment 15 exceeded 5 ms in lunate, schapoid and triquetrum. This indication of fractures is in good agreement with the experimental results where the corresponding bones resulted in fractures in experiment 15. HEX 4.0 was an improved upper extremity of the THUMS SAFER considering an increased mesh density. It is also capable of indicating fractures and corresponding positions in the form of analyzes of occurring stresses and strains. Nevertheless, improvements and further validation of HEX 4.0 has been proposed in the future work section.
Globalt, dör varje år ungefär 1.2 miljoner personer på grund av trafi kolyckor. Skador på övre extremitet utgör 18% till 25% av alla skador inom bilolyckor. För att kunna analysera dessa krockrelaterade skador används humanmodeller(HBM) som komplement för FE-simuleringar. Ett exempel på en HBM är THUMS SAFER som är baserad på en "50 percentile" amerikans man. Målet med denna studie är att förbättra över extremiten av THUMS SAFER med avseende på Autolivs krav för att bättre kunna förutspå frakturer. Dessutom validerades detta mot Forman experiment(Forman, et al., The journal of trauma and acute care surgery, vol. 77, 2014) där övre extremitet av människokadaver blev axiellt påverkade för att replikera en bilkollsion. Detta gjordes genom att generera STL-geometrin av en övre extremitet med segmentering av medicinska bilder av en höger människohand i kombination med färdig STL-geometri av underarmen från Piper projektet. STL-geometrin av den segmenterande människohanden och Piper underarmen integrerades och en komplett STL-geometri av övre extremiteten erhölls. Baserad på den kompletta STL-geometrin byggdes FE-armen HEX 4.0 med modellering av ben, ligament, mjukvävnad samt hud med motsvarande materialval i enighet med Autolivs krav. Modellen HEX 4.0 förbättrades i form av en ökad mesh densitet från medelvärdet 94% till 98%. Den validerades även gentemot data från Forman experimentet för experiment 5, 6 och 15. Det påvisade en god korrelation på accelerations kurvorna mellan de simulerade och experimentella värdena för de tre experimenten. Reaktionskraften i armbågen jämfördes för experiment 15 där den simulerade värdet 5.7 kN skiljde sig med en faktor 1.4 från 4 kN för experimentet. Ytterligare analyserades första huvudtöjningarna som uppkom i HEX 4.0 vid 17 ms, då den högsta accelerationen uppnådes för experiment 5 och 6. Det visades att båda experimenten låg nära gränsen för benfraktur, däremot uppkom det högsta värdet e5=9.8E-03 i radius för experiment 5, samt e6=9.3E-03 i ett ligament för experiment 6. Dessutom överskred gränsen för benfrakturer för experiment 15 efter 5 ms i lunate, schapoid och triquetrum. Denna indikation av frakturer stämmer väl med resultatet av experimentet där motsvarande benen resulterades i frakturer i experiment 15. HEX 4.0 är en förbättrad övre extremitet av THUMS SAFER i form av förbättrad meshdensitet. Den är även kapabel att indikera frakturer och motsvarande position i form av analyser på förekommande spänningar och töjningar. Förbättringar och ytterligare validering av HEX 4.0 föreslås för framtida arbete.

This research utilizes CFD to analyze blood flow through pathways representative of central shunts, commonly used as part of the Fontan procedure to treat cyanotic heart disease. In the first part of this research, a parametric study of steady, Newtonian blood flow through parabolic pathways was performed to demonstrate the effect that flow pathway curvature has on wall shear stress distribution and flow energy losses. In the second part, blood flow through two shunts obtained via biplane angiograms is simulated. Pressure boundary conditions were obtained via catheterization. Results showed that wall shear stresses were of sufficient magnitude to initiate platelet activation, a precursor for thrombus formation. Steady results utilizing time-averaged boundary conditions showed excellent agreement with the time-averaged results obtained from pulsatile simulations. For the points of interest in this research, namely wall shear stress distribution and flow energy loss, the Newtonian viscosity model was found to yield acceptable results.

Microcirculatory vessels are lined by endothelial cells (ECs) which are surrounded by a single or multiple layer of smooth muscle cells (SMCs). Spontaneous and agonist induced spatiotemporal calcium (Ca2+) events are generated in ECs and SMCs, and regulated by complex bi-directional signaling between the two layers which ultimately determines the vessel tone. The contractile state of microcirculatory vessels is an important factor in the determination of vascular resistance, blood flow and blood pressure. This dissertation presents theoretical insights into some of the important and currently unresolved phenomena in microvascular tone regulation. Compartmental and continuum models of isolated EC and SMC, coupled EC-SMC and a multi-cellular vessel segment with deterministic and stochastic descriptions of the cellular components were developed, and the intra- and inter-cellular spatiotemporal Ca2+ mobilization was examined. Coupled EC-SMC model simulations captured the experimentally observed localized subcellular EC Ca2+ events arising from the opening of EC transient receptor vanilloid 4 (TRPV4) channels and inositol triphosphate receptors (IP3Rs). These localized EC Ca2+ events result in endothelium-derived hyperpolarization (EDH) and Nitric Oxide (NO) production which transmit to the adjacent SMCs to ultimately result in vasodilation. The model examined the effect of heterogeneous distribution of cellular components and channel gating kinetics in determination of the amplitude and spread of the Ca2+ events. The simulations suggested the necessity of co-localization of certain cellular components for modulation of EDH and NO responses. Isolated EC and SMC models captured intracellular Ca2+ wave like activity and predicted the necessity of non-uniform distribution of cellular components for the generation of Ca2+ waves. The simulations also suggested the role of membrane potential dynamics in regulating Ca2+ wave velocity. The multi-cellular vessel segment model examined the underlying mechanisms for the intercellular synchronization of spontaneous oscillatory Ca2+ waves in individual SMC. From local subcellular events to integrated macro-scale behavior at the vessel level, the developed multi-scale models captured basic features of vascular Ca2+ signaling and provide insights for their physiological relevance. The models provide a theoretical framework for assisting investigations on the regulation of vascular tone in health and disease.

Myocardial infarction (i.e., a heart attack) is the most common heart disease in the United States. Mitral valve regurgitation, or the backflow of blood into the atrium from the left ventricle, is one of the complications associated with myocardial infarction. In this dissertation, a validated model of a sheep heart that has suffered myocardial infarction has been employed to study mitral valve regurgitation. The model was rebuilt with the knowledge of geometrical changes captured with MRI technique and is assigned with anisotropic, inhomogeneous, nearly incompressible and highly non-linear material properties. Patch augmentation was performed on its anterior leaflet, using a simplified approach, and its posterior leaflet, using a more realistic approach. In this finite element simulation, we virtually installed an elliptical patch within the central portion of the posterior leaflet. To the best of the author’s knowledge, this type of simulation has not been performed previously. In another simulation, the effect of patch within the anterior leaflet was simulated. The results from the two different surgical simulations show that patch implantation helps the free edges of the leaflets come close to one another, which leads to improved coaptation. Additionally, the changes in chordal force distributions are also reported. Finally, this study answers a few questions regarding mitral valve patch augmentation surgeries and emphasizes the importance of further investigations on the influence of patch positioning and material properties on key outcomes. The ultimate goal is to use the proposed techniques to assess human models that are patient-specific.

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Esta tese compõe o conjunto de estudos realizados na Universidade Federal da Bahia, a partir do Programa de Pós-Graduação em Educação, Linha de Pesquisa Educação, Cultura Corporal e Lazer. Insere-se especificamente nos estudos realizados pelo Grupo de Estudo e Pesquisa em Educação Física, Esporte e Lazer (LEPEL/PPGE/FACED/UFBA) e responde a perguntas científicas relacionadas à pesquisa matricial sobre “Problemáticas significativas do Trabalho Pedagógico, da Produção do Conhecimento, das Políticas Públicas e da Formação de Professores de Educação Física e Esporte”. Tem como objeto de estudo o trato com o conhecimento na formação de Professores de Educação Física. Delimita como pergunta de investigação quais as contribuições da Psicologia Histórico-Cultural, da Pedagogia Histórico-Crítica e, da Abordagem Crítico-Superadora do Ensino da Educação Física para enfrentar as contradições presentes no currículo de formação de professores referentes à negação do conhecimento e, o trato com o conhecimento a partir de abordagens biologicistas, naturalistas, mecanicistas, que fragmentam corpo-mente e teoria-prática. A hipótese tratou do enfrentamento do projeto de formação de professores que defende a divisão dos cursos de Educação Física, dando ênfase à questão da saúde, a partir das possíveis contribuições de um conjunto teórico baseado na referência marxista e, da experiência pedagógica no ensino da Biomecânica Aplicada à Educação Física, conteúdo do eixo dos Fundamentos, da área da Saúde relacionado com o Eixo do Conteúdo Específico da Cultura Corporal do Curso de Licenciatura em Educação Física, de caráter ampliado, da Faculdade de Educação da Universidade Federal da Bahia. Os dados levantados e sistematizados foram coletados: (a) na bibliografia sobre os pressupostos teóricos; (b) na legislação, nos bancos de dados do MEC e, em dissertações e teses; (c) in locus, na experiência pedagógica desenvolvida no ensino da disciplina Biomecânica Aplicada à Educação Física na FACED/UFBA. Os procedimentos de investigação foram: análises de conteúdo; descrição densa em relatórios de campo; e elaboração de sínteses estabelecendo nexos e relações que permitiram a conclusão da tese. A tese apresenta como pressupostos, epistemológico a teoria do conhecimento Materialista Histórico Dialético, do desenvolvimento humano a Teoria Histórico Cultural, pedagógico a Teoria Pedagogia Histórico-Crítica e, no ensino da Educação Física, a Abordagem Crítico-Superadora. O objetivo diz respeito às contribuições dos pressupostos teóricos no trato com o conhecimento, em especial da área da saúde, no currículo de formação de professores de Educação Física, na perspectiva da superação de contradições e, de contribuições para consolidar uma consistente formação teórica, fundamentada na teoria do conhecimento do Materialismo Histórico Dialético. Conclui-se, apresentando, a partir dos pressupostos de referência marxista, elementos teórico-práticos, em que destacamos os sistemas de complexos, no trato com o conhecimento, no currículo de formação de professores de Educação Física, no marco de um curso único, de licenciatura ampliada.
ABSTRACT This thesis composes the set of studies performed at the Federal University of Bahia, through the Graduate Program in Education, Research Line on Education, Body Culture and Leisure. It is specifically inserted in the studies performed by the Study and Research Group in Physical Education, Sport and Leisure (LEPEL/PPGE/FACED/UFBA), and answers scientific questions related to the matrix research on “Significant issues on Pedagogical Work, Knowledge Production, Public Policies, and Formation of Physical Education and Sport Teachers”. Its object of study is the treatment of knowledge in the formation of Physical Education Teachers. It delimits as its research question what are the contributions of the Historical-Cultural Psychology, the Historical-Critical Pedagogy, and the Critical-Overcoming Approach of Physical Education Teaching to face the contradictions present in the teacher formation curriculum that refer to the knowledge denial, and the treatment of knowledge through biological, naturalistic, mechanistic approaches that fragment body-mind and theory-practice. The hypothesis dealt with the confrontation of the teacher formation project that defends the division of the Physical Education undergraduate programs, emphasizing the health matter, through the possible contributions of a theoretical set based on the Marxist reference, and the pedagogical experience in the teaching of Biomechanics Applied to Physical Education, subject of the Fundamentals of the Health area axis, related to the Axis of the Specific Content of Body Culture of the Physical Education Undergraduate Program, with extended character, of the College of Education in the Federal University of Bahia. The systematized data were collected: (a) in the bibliography about the theoretical assumptions; (b) in legislation, in the MEC databases, and in dissertations and theses; (c) in locus, in the pedagogical experience developed in the teaching of the Biomechanics Applied to Physical Education course at FACED/UFBA. The investigation procedures were: content analysis; dense description in field reports; and elaboration of syntheses establishing links and relations that allowed the conclusion of the thesis. The thesis presents as its assumptions: epistemologically, the Historical Dialectical Materialism theory of knowledge; on human development, the Cultural Historical Theory; pedagogically, the Historical-Critical Pedagogy Theory; and on the teaching of Physical Education, the Critical-Overcoming Approach. The objective concerns the contributions of the theoretical assumptions to the treatment of the knowledge, especially of the health area, in the curriculum of Physical Education teachers’ formation, with the perspective of overcoming contradictions, and of contributions to consolidate a consistent theoretical formation, based on the Historical and Dialectical Materialism theory of knowledge. It was concluded, presenting, through the assumptions of Marxist reference, theoretical-practical elements, where we highlight the systems of complexes, in the treatment of knowledge, in the curriculum of Physical Education teachers’ formation, within the framework of a single, extended degree.
RESUMEN Esta tesis compone el conjunto de estudios realizados en la Universidad Federal de Bahía, a partir del Programa de Postgrado en Educación, Línea de Investigación Educación, Cultura Corporal y Ocio. Se inserta específicamente en los estudios realizados por el Grupo de Estudio e Investigación en Educación Física, Deporte y Ocio (LEPEL / PPGE / FACED / UFBA) y responde a preguntas científicas relacionadas con la investigación matricial sobre "Problemáticas significativas del trabajo pedagógico, de la producción del conocimiento, de las Políticas Públicas y de la Formación de Profesores de Educación Física y Deporte. Tiene como objeto de estudio el trato con el conocimiento en la formación de Profesores de Educación Física. En el caso de la enseñanza de la educación física, se debe tener en cuenta que las contribuciones de la Pscicología Histórico-Cultural, de la Pedagogía Histórico-Crítica y del Enfoque Crítico-Superadora de la Enseñanza de la Educación Física para enfrentar las contradicciones presentes en el currículo de formación de profesores referentes a la negación del conocimiento y, trato con el conocimiento a partir de enfoques biologicistas, naturalistas, mecanicistas, que fragmentan cuerpo-mente y teoría-práctica. La hipótesis trató del enfrentamiento del proyecto de formación de profesores que defiende la división de los cursos de Educación Física, dando énfasis a la cuestión de la salud, a partir de las posibles contribuciones de un conjunto teórico basado en la referencia marxista y de la experiencia pedagógica en la enseñanza de la Biomecánica Aplicada a la Educación Física, el contenido del eje de los Fundamentos, del área de la Salud relacionado con el Eje del Contenido Específico de la Cultura Corporal del Curso de Licenciatura en Educación Física, de carácter ampliado, de la Facultad de Educación de la Universidad Federal de Bahía. Los datos levantados y sistematizados fueron recolectados: (a) en la bibliografía sobre los presupuestos teóricos; (b) en la legislación, en los bancos de datos del MEC y en disertaciones y tesis; (c) in locus, en la experiencia pedagógica desarrollada en la enseñanza de la disciplina Biomecánica Aplicada a la Educación Física en la FACED/UFBA. Los procedimientos de investigación fueron: análisis de contenido; descripción densa en informes de campo; y elaboración de síntesis estableciendo nexos y relaciones que permitieron la conclusión de la tesis. La tesis presenta como presupuestos, epistemológico la teoría del conocimiento Materialista Histórico Dialéctico, del desarrollo humano la Teoría Histórico Cultural, pedagógica la Teoría Pedagogía Histórico-Crítica y, en la enseñanza de la Educación Física, el Enfoque Crítico-Superadora. El objetivo se refiere a las contribuciones de los presupuestos teóricos en el trato con el conocimiento, en especial del área de la salud, en el currículo de formación de profesores de Educación Física, en la perspectiva de la superación de contradicciones y de contribuciones para consolidar una consistente formación teórica, fundamentada en la teoría del conocimiento del materialismo histórico dialéctico. Se concluye, presentando, a partir de los presupuestos de referencia marxista, elementos teórico-prácticos, en que destacamos los sistemas de complejos, en el trato con el conocimiento, en el currículo de formación de profesores de Educación Física, en el marco de un curso único, de licenciatura ampliada.
SOMMARIO Questa tesi compone l'accumulo degli studi effettuati presso l'Università Federale di Bahia, a partire dal Programma Post-Laurea in Educazione, Linea di Ricerca, Educazione, Cultura Corporale e Ricreazione. E 'specificamente inserito nell'analisi del Gruppo di Studio i Ricerca sull'Educazione Fisica, Sport i Ricreazione (LEPEL / PPGE / FACED / UFBA) e risponde a domande scientifiche relative alla ricerca di base su i "Problemi significativi del Lavoro Pedagogico, Produzione della Conoscenza" , delle Politiche Pubbliche e della Formazione degli Insegnanti di Educazione Fisica e Sport ". Ha come oggetto di studio il contatto con la conoscenza nella formazione degli insegnanti di Educazione Fisica. Delimita come una domanda di analisi quali sono i contributi della Psicologia Storico-Culturale, della Pedagogia Storico-Critica e dell'Approccio Critico-Superadora dell'Insegnamento dell'Educazione Fisica per affrontare le contraddizioni presenti nel curriculum di formazione degli insegnanti relativo alla negazione della conoscenza e, al contatto con la conoscenza di approcci biologicisti, naturalistici, meccanicistiche, che frammentano mente-corpo e teoria-pratica. L'ipotesi ha esaminato il confronto del progetto di formazione degli insegnanti che difende la divisione dei corsi di Educazione Fisica, sottolineando il problema della salute, basato sui possibili contributi di uma compilazione teorica basata sul riferimento marxista e, dell'esperienza pedagogica nell'insegnamento della Biomeccanica Applicata all'Educazione Fisica, contenuto dell'asse dei Fondamenti, dell'area della Salute relativa all'Asse del Contenuto Specifico della Cultura Corporale del Corso di Laurea in Educazione Fisica, di carattere estensivo, della Facoltà di Educazione dell'Università Federale di Bahia. I dati raccolti e sistematizzati sono stati ripresi: (a) nella bibliografia sulle ipotesi teoriche; (b) nella legislazione, nelle banche dati MEC, nelle dissertazioni e nelle tesi; (c) in locus, nell'esperienza pedagogica sviluppata nell'insegnamento della disciplina Biomeccanica Applicata all'Educazione Fisic nel FACED/UFBA. Le procedure investigative erano: analisi del contenuto; descrizione spesse negli articoli di campo; ed elaborazione di sintesi che stabiliscono collegamenti e relazioni che hanno permesso la conclusione della tesi. La tesi presenta come presupposti, epistemologici la teoria della conoscenza Materialista Storica-Dialettica, dallo sviluppo umano alla Teoria Storica Culturale, pedagogica alla Teoria Pedagogica Storico-Critica e, nell'insegnamento dell'Educazione Fisica, l'Approccio Critico-Superadora. L'obiettivo è di contribuire ai presupposti teorici nel trattamento della conoscenza, specialmente nell'area della salute, nel curriculum per la formazione degli insegnanti di Educazione Fisica, al fine di superare le contraddizioni e contribuire a consolidare una coerente formazione teórica, basata sulla teoria della conoscenza del Materialismo Storico Dialettico. Si conclude, presentando, basato su presupposti di riferimento marxista, elementi teorico-pratici, in cui si evidenziano i sistemi di complessi, nel trattamento della conoscenza, nel curriculum per la formazione degli insegnanti di Educazione Fisica, nell'ambito di un corso di laurea unico e prolungato.

Statistical data suggests that increased use of evidence-based medical therapies has largely contributed to the decrease in American death rate caused by heart disease. And my studies are about two applications of magnetic resonance imaging (MRI) as a non-invasive approach in evidence-based health care research. In my first study, the achievement of a pulmonary valve replacement surgery was assessed on a patient with tetralogy of Fallot (TOF). In order to evaluate the remodeling of right ventricle, two biventricular finite element models were built up for pre-surgical images and post-surgical images. In my second study, 3D Lagrangian strains and torsion in the left ventricle of ten rats were investigated using Displacement ENcoding with Stimulated Echoes (DENSE) cardiac magnetic resonance (CMR) images. Tools written in MATLAB were developed for 2D contouring, 3D modeling, strain and torsion computations, and statistical comparison across subjects.

In total knee arthroplasty, implants are aligned perpendicular to the mechanical axis of the lower limb (the line connecting the centre of the hip to the centre of the ankle). Currently, there is a very precise method for locating the centre of the hip, but not so for the centre of the ankle joint. In this study, I report on the two primary contributions I have made to the problem of locating a meaningful ankle centre for use in the computer-assisted total knee arthroplasty system we are developing at the University of British Columbia. The first contribution I made was by deriving the algorithms for use in fitting mathematical models of the ankle (both ball-in-socket and biaxial) to subject-specific data, and then performing the numerical and physical simulations to identify which algorithms are best suited to each model for use with our computer-assisted surgical system. The second contribution I made was my investigation of locating the ankle centre using these different ankle models mentioned above, in weight-bearing and non-weight-bearing, compared to locating the ankle centre using anatomic digitization. By conducting tests on 12 live subjects to identify the precision of each technique I found that the spherical method of ankle centre localization in the non-weight-bearing was the most reliable method of predicting the location of the ankle centre in weight-bearing.

In this Thesis we develop mathematical models to analyze two proposed causative mechanisms for the ventricular expansion observed in hydrocephalus: cerebrospinal fluid pulsations and small transmantle pressure gradients. To begin, we describe a single compartment model and show that such simple one-dimensional models cannot represent the complex dynamics of the brain. Hence, all subsequent models of this Thesis are spatio-temporal. Next, we develop a poroelastic model to analyze the fluid-solid interactions caused by the pulsations. Periodic boundary conditions are applied and the system is solved analytically for the tissue displacement, pore pressure, and fluid filtration. The model demonstrates that fluid oscillates across the brain boundaries. We develop a pore flow model to determine the shear induced on a cell by this fluid flow, and a comparison with data indicates that these shear forces are negligible. Thus, only the material stresses remain as a possible mechanism for tissue damage and ventricular expansion. In order to analyze the material stresses caused by the pulsations, we develop a fractional order viscoelastic model based on the linear Zener model. Boundary conditions appropriate for infants and adults are applied and the tissue displacement and stresses are solved analytically. A comparison of the tissue stresses to tension data indicates that these stresses are insufficient to cause tissue damage and thus ventricular expansion. Using age-dependent data, we then determine the fractional Zener model parameter values for infant and adult cerebra. The predictions for displacement and stresses are recomputed and the infant displacement is found to be unphysical. We propose a new infant boundary condition which reduces the tissue displacement to a physically reasonable value. The model stresses, however, are unchanged and thus the pulsation-induced stresses remain insufficient to cause tissue damage and ventricular expansion. Lastly, we develop a fractional hyper-viscoelastic model, based on the Kelvin- Voigt model, to obtain large deformation predictions. Using boundary conditions and parameter values for infants, we determine the finite deformation caused by a small pressure gradient by summing the small strain deformation resulting from pressure gradient increments. This iterative technique predicts that pediatric hydrocephalus may be caused by the long-term existence of small transmantle pressure gradients. We conclude the Thesis with a discussion of the results and their implications for hydrocephalus research as well as a discussion of future endeavors.

Osteoporosis is a common metabolic bone disorder characterized by low bone mass and microstructural degradation of bone tissue due to derailed bone remodeling process. A deeper understanding of mechanobiological phenomenon modulating bone remodeling response to mechanical load in a healthy bone is crucial to develop treatments for this bone remodeling disease by restoring bone integrity, and preventing further bone loss and fracture. Rodent models have been provided invaluable insight into the mechanobiological mechanisms regulating the bone adaptation response to dynamic mechanic stimuli. However, use of avian models may suggest novel insight into the mechanisms managing bone adaptation to dynamic load since the bird bones have some distinctive features to the mammal bones.

This dissertation sheds light on these aspects by means of assessing mechanical environment of cortical and cancellous tissue to in vivo dynamic compressive loading within the mouse tibia and chukar partridge tibiotarsus using microCT-based finite element model in combination with diaphyseal strain gauge measures. While the mouse tibial loading model showed that cancellous strains were lower than those in the midshaft cortical bone, cancellous strains were greater than those in the midshaft cortical bone for the bird tibiotarsal loading model. Sensitivity analyses for both the mouse model and the bird model demonstrated that the material property of cortical bone was the most significant model parameter. Despite the correlations between the computationally-modeled strains and strain gradients, and histologically-measured bone formation thickness at the mid-diaphyseal cross-section of the mouse tibia, no correlation existed between the modeled strains and bone formation measures at the mid-diaphyseal cross-sections of the bird tibiotarsus. A weak correlation found between the mid-diaphyseal strain gradients and bone formation thickness for birds. Further studies in this direction will enhance the interpretation of how the bone adaptation mechanism in a healthy bone is modulated to maintain bone integrity.

Uterine motility is responsible for carrying out important processes throughout all phases of the female reproductive cycle, including sperm transport, menstruation, and embryo implantation. We present a model of intra-uterine fluid flow in a sagittal cross-section of the uterus by inducing peristalsis in a channel. The peristaltic waveform emerges from the coupling of cellular models to elastic walls and viscous fluid. This is an integrative multiscale spatial model that takes as input the fluid viscosity, passive uterine tissue properties, and a prescribed wave of membrane depolarization. Following Bursztyn et al. [1], the voltage pulse drives the calcium dynamics inside each smooth muscle cell along the uterine walls. This, in turn, drives the formation of cross-bridges in the cell which generate the contractile muscle forces. The forces predicted by this new model are coupled to the elastic channel walls and the viscous, incompressible fluid within the channel using an immersed boundary framework [2] The main contributions of this dissertation are two-fold. First, we present a modified Hai-Murphy model of uterine smooth muscle cell force generation that accounts for the displacement of myosin cross-bridge heads relative to their binding sites. Second, we couple this microscale model of force generation with an organ level model of the uterine channel that captures the elastic properties of the uterine walls and a viscous, incompressible fluid. We then examine how fluid transport is affected by changes on the molecular and cellular scales. In particular, we show how deficiencies in phosphorylation and calcium uptake affect intra-uterine fluid flow
acase@tulane.edu

Modern lower limb prostheses are devices that replace missing limbs, making it possible for lower limb amputees to walk again. Most commercially available prosthetic limbs lack intelligence and passive adaptive capabilities, and none available can adapt on a step by step basis. Often, amputees experience a loss of terrain adaptability as well as stability, leaving the amputee with a severely altered gait. This work is focused on the development of a semi-active damping system for use in intelligent terrain adaptive ankle prostheses. The system designed consists of an optimized hydraulic cylinder with an electronic servo valve which throttles the hydraulic fluid flowing between the cylinder’s chambers, acting on the prosthesis joint with a moment arm in series with a carbon spring foot. This provides the capability to absorb energy during the amputees gait cycle in a controlled manner, effectively allowing the passive dynamic response to be greatly altered continuously by leveraging a small energy source. A virtual simulation of an amputee gait cycle with the adaptive semi-active ankle design revealed the potential to replicate adaptive abilities of the human ankle. The results showed very similarly that irregularities in amputee biomechanics can be greatly compensated for using semi-active damping.

In der vorliegenden Arbeit wird eine Methodik zur Entwicklung mechanischer Simulationen der Interaktion Sportler-Sportgerät-Umwelt zur Untersuchung der Funktionalität von Sportgeräten konzipiert und vorgestellt. Die mechanische Simulation ist die gegenständliche Nachbildung spezieller Teilaspekte des Sportlers, z.B. der Körperform, der Trägheitseigenschaften, der Masse, der Interaktionskräfte zur Umwelt oder charakteristischer Bewegungsabläufe zum Zweck der Durchführung gezielter Experimente zur Untersuchung des dynamischen Systemverhaltens Sportler-Sportgerät-Umwelt. Dazu werden drei Fallbeispiele aus der Forschungstätigkeit der Arbeitsgruppe HLST an der Technischen Universität Chemnitz mit Methoden zur Verifikation von Simulationsmodellen – dem strukturierten Durchgehen, der Validierung im Dialog und dem Schreibtischtest – analysiert. Die Analyseergebnisse werden in eine Grobstruktur eingebettet, die aus relevanten Vorarbeiten zur Anwendung der Allgemeinen Modelltheorie abgeleitet ist. Die in den jeweiligen Fallbeispielen verwendeten Prozessschritte, Methoden und Werkzeuge werden dargestellt und die Entwicklungsergebnisse erörtert. Im Abschluss jedes Fallbeispiels wird der Entwicklungsprozess anhand von einheitlichen Kriterien bewertet. In einem abschließenden Schritt erfolgt die Zusammenführung der im Stand der Technik dargelegten Grundlagen und der in den drei Fallbeispielen gewonnenen Informationen zu einer strukturieren und kommentierten Methodik.:1 Einleitung 8 1.1 Definitionen 8 1.2 Einsatzgebiete der mechanischen Simulation 11 1.2.1 Überblick 11 1.2.2 Sicherheit gegen Versagen 12 1.2.3 Konformität 14 1.2.4 Funktionalität 15 1.3 Motivation und Zielsetzung 16 1.4 Aufbau der Arbeit 16 2 Theoretische Grundlagen 18 2.1 Experimentelle Methoden der Sportgeräteentwicklung 18 2.1.1 Einordnung nach Odenwald (2006) 18 2.1.2 Einordnung nach Witte (2013) 19 2.1.3 Einordnung nach Senner (2001) 20 2.1.4 Eigene Systematisierung 23 2.2 Allgemeine Modelltheorie 26 2.3 Existierende Ansätze für die Applikation der Allgemeinen Modelltheorie 29 2.3.1 Anwendung der AMT in der Chemie 29 2.3.2 Anwendung der AMT in der Biomechanik 30 2.3.3 Anwendung der AMT in Logistik und Produktion 32 2.3.4 Fazit 37 3 Präzisierung der Problemstellung 38 4 Methodik 39 5 Fallbeispiel Schwimmanzug – Strömungswiderstand 41 5.1 Vorbemerkungen 41 5.2 Aufgabenanalyse 42 5.2.1 Definition der zu untersuchenden Funktionalität des Sportgeräts 42 5.2.2 Analyse der zugrundeliegenden technischen Funktion des Sportgeräts 42 5.2.3 Analyse der Simulationswürdigkeit 43 5.2.4 Identifikation des Originals 47 5.3 Modellformulierung 48 5.3.1 Modellansatz 48 5.3.2 Modellsynthese 50 5.4 Modellimplementierung 53 5.4.1 Herstellung des Strömungskörpers 53 5.4.2 Simulation der Fortbewegung im Wasser 54 5.5 Modellanwendung 57 5.6 Modellüberprüfung 60 5.6.1 Abgleich zwischen den experimentellen Ergebnissen und dem theoretischen Modell 60 5.6.2 Vergleich mit dem Original 62 5.7 Fazit 67 6 Fallbeispiel Laufschuh – Stoßabsorption 69 6.1 Vorbemerkungen 69 6.2 Aufgabenanalyse 69 6.2.1 Definition der zu untersuchenden Funktionalität 69 6.2.2 Analyse der zugrundeliegenden technischen Funktion des Sportgeräts 71 6.2.3 Analyse der Simulationswürdigkeit 71 6.2.4 Definition des Originals 72 6.3 Modellformulierung 72 6.3.1 Modellansatz 72 6.3.2 Systemanalyse 72 6.3.3 Modellsynthese 77 6.4 Modellimplementierung 78 6.4.1 Krafterzeugung 78 6.4.2 Kraftübertragung 79 6.5 Modellanwendung 81 6.6 Modellüberprüfung 82 6.6.1 Soll-Istwert-Vergleich 82 6.6.2 Reliabilität 83 6.6.3 Korrelation zu Stoßbelastungsvariablen 85 6.6.4 Ereignisvaliditätstest: Sohlentemperatur 86 6.6.5 Ereignisvaliditätstest: Sohlendeformation 88 6.7 Fazit 91 7 Fallbeispiel Fußballschuh – Traktionseigenschaften 94 7.1 Vorbemerkungen 94 7.2 Aufgabenanalyse 94 7.2.1 Definition der zu untersuchenden Funktionalität 94 7.2.2 Analyse der zugrundeliegenden technischen Funktion des Sportgeräts 95 7.2.3 Analyse der Simulationswürdigkeit 96 7.2.4 Definition des Originals 97 7.3 Modellformulierung 98 7.3.1 Modellansatz 98 7.3.2 Systemanalyse 98 7.3.3 Modellsynthese 106 7.4 Modellimplementierung 107 7.5 Modellanwendung 110 7.6 Modellüberprüfung 114 7.6.1 Reliabilität 114 7.6.2 Sensitivitätsanalyse: Normalkraft 114 7.6.3 Sensitivitätsanalyse: Kraftanstieg horizontal 116 7.6.4 Vergleich mit der Realität 116 7.7 Fazit 117 8 Methodik zur Entwicklung mechanischer Simulationen der Interaktion Sportler-Sportgerät-Umwelt 119 8.1 Schematische Darstellung 119 8.2 Erläuterung der Vorgehensempfehlung 120 8.2.1 Klärung der Problemstellung 120 8.2.2 Modellbildung 122 8.2.3 Modellanwendung 124 9 Schlussbetrachtung 126 Literaturverzeichnis 128 Tabellenverzeichnis 133 Abbildungsverzeichnis 135 Danksagung 138 Selbstständigkeitserklärung 139 Lebenslauf 140
In this dissertation a methodology is conceived that aims to structure the development process of test arrangements that mechanically simulate the interaction of athlete, sports equipment and environment. Mechanical simulation in this context is defined as the physical replication of specific properties of the athlete (e.g. the shape of the human body, body weight, joint kinematics, inertia, external forces in specific movements) in order to conduct experiments to investigate the dynamic behavior of the system athlete-equipment-environment. Therefore, three case studies of mechanical simulation models that have been developed at Technische Universität Chemnitz are analyzed by applying the validation and verification methods “structured walkthrough”, “face validity” and “desk checking”. The results of that analysis are embedded into a framework that is derived by literature review on applied model theory. For each of the three development processes the procedure model is identified and main tools and methods are discussed. Every case study is finally assessed by using standardized evaluation criterions. Finally, the main findings of the analysis of the case studies as well as knowledge obtained by reviewing the state of the art in model theory and simulation methods are used to build up a structured and commentated guideline.:1 Einleitung 8 1.1 Definitionen 8 1.2 Einsatzgebiete der mechanischen Simulation 11 1.2.1 Überblick 11 1.2.2 Sicherheit gegen Versagen 12 1.2.3 Konformität 14 1.2.4 Funktionalität 15 1.3 Motivation und Zielsetzung 16 1.4 Aufbau der Arbeit 16 2 Theoretische Grundlagen 18 2.1 Experimentelle Methoden der Sportgeräteentwicklung 18 2.1.1 Einordnung nach Odenwald (2006) 18 2.1.2 Einordnung nach Witte (2013) 19 2.1.3 Einordnung nach Senner (2001) 20 2.1.4 Eigene Systematisierung 23 2.2 Allgemeine Modelltheorie 26 2.3 Existierende Ansätze für die Applikation der Allgemeinen Modelltheorie 29 2.3.1 Anwendung der AMT in der Chemie 29 2.3.2 Anwendung der AMT in der Biomechanik 30 2.3.3 Anwendung der AMT in Logistik und Produktion 32 2.3.4 Fazit 37 3 Präzisierung der Problemstellung 38 4 Methodik 39 5 Fallbeispiel Schwimmanzug – Strömungswiderstand 41 5.1 Vorbemerkungen 41 5.2 Aufgabenanalyse 42 5.2.1 Definition der zu untersuchenden Funktionalität des Sportgeräts 42 5.2.2 Analyse der zugrundeliegenden technischen Funktion des Sportgeräts 42 5.2.3 Analyse der Simulationswürdigkeit 43 5.2.4 Identifikation des Originals 47 5.3 Modellformulierung 48 5.3.1 Modellansatz 48 5.3.2 Modellsynthese 50 5.4 Modellimplementierung 53 5.4.1 Herstellung des Strömungskörpers 53 5.4.2 Simulation der Fortbewegung im Wasser 54 5.5 Modellanwendung 57 5.6 Modellüberprüfung 60 5.6.1 Abgleich zwischen den experimentellen Ergebnissen und dem theoretischen Modell 60 5.6.2 Vergleich mit dem Original 62 5.7 Fazit 67 6 Fallbeispiel Laufschuh – Stoßabsorption 69 6.1 Vorbemerkungen 69 6.2 Aufgabenanalyse 69 6.2.1 Definition der zu untersuchenden Funktionalität 69 6.2.2 Analyse der zugrundeliegenden technischen Funktion des Sportgeräts 71 6.2.3 Analyse der Simulationswürdigkeit 71 6.2.4 Definition des Originals 72 6.3 Modellformulierung 72 6.3.1 Modellansatz 72 6.3.2 Systemanalyse 72 6.3.3 Modellsynthese 77 6.4 Modellimplementierung 78 6.4.1 Krafterzeugung 78 6.4.2 Kraftübertragung 79 6.5 Modellanwendung 81 6.6 Modellüberprüfung 82 6.6.1 Soll-Istwert-Vergleich 82 6.6.2 Reliabilität 83 6.6.3 Korrelation zu Stoßbelastungsvariablen 85 6.6.4 Ereignisvaliditätstest: Sohlentemperatur 86 6.6.5 Ereignisvaliditätstest: Sohlendeformation 88 6.7 Fazit 91 7 Fallbeispiel Fußballschuh – Traktionseigenschaften 94 7.1 Vorbemerkungen 94 7.2 Aufgabenanalyse 94 7.2.1 Definition der zu untersuchenden Funktionalität 94 7.2.2 Analyse der zugrundeliegenden technischen Funktion des Sportgeräts 95 7.2.3 Analyse der Simulationswürdigkeit 96 7.2.4 Definition des Originals 97 7.3 Modellformulierung 98 7.3.1 Modellansatz 98 7.3.2 Systemanalyse 98 7.3.3 Modellsynthese 106 7.4 Modellimplementierung 107 7.5 Modellanwendung 110 7.6 Modellüberprüfung 114 7.6.1 Reliabilität 114 7.6.2 Sensitivitätsanalyse: Normalkraft 114 7.6.3 Sensitivitätsanalyse: Kraftanstieg horizontal 116 7.6.4 Vergleich mit der Realität 116 7.7 Fazit 117 8 Methodik zur Entwicklung mechanischer Simulationen der Interaktion Sportler-Sportgerät-Umwelt 119 8.1 Schematische Darstellung 119 8.2 Erläuterung der Vorgehensempfehlung 120 8.2.1 Klärung der Problemstellung 120 8.2.2 Modellbildung 122 8.2.3 Modellanwendung 124 9 Schlussbetrachtung 126 Literaturverzeichnis 128 Tabellenverzeichnis 133 Abbildungsverzeichnis 135 Danksagung 138 Selbstständigkeitserklärung 139 Lebenslauf 140

This thesis examined the immediate biomechanical effects of valgus unloader brace application in participants with moderate medial compartment knee osteoarthritis during gait. Thirty-three individuals were prescribed a valgus unloader brace. 3D knee moments and angles were calculated during walking with and without the brace. Principal Component Analysis identified amplitude and temporal changes of the moment and angle waveforms during gait. Three groups were identified based on the change in knee adduction moment magnitude with brace application. Two-Way ANOVA tested for differences among groups and conditions in principal component scores, as well as discrete varus thrust values. There existed three subgroups of participants identified by different gait adaptations to brace application. The brace had temporal and magnitude effects on 3D kinetics and kinematics for the participant group. This study showed that the brace does not provide a consistent change to knee joint mechanics. These results have implications for brace prescription.

碩士
國立臺北科技大學
機械工程系機電整合碩士班
107
As the advancement of additive manufacturing technology, many internationally renowned shoe brands have developed new footwear by utilizing additive manufacturing technology. The footwear made by additive manufacturing technology is featured with cellular midsole structure. It is also aimed to have better biomechanical performance during heel strike and midstance phases of gait. It has been reported in literature that the cellular structure with characteristic of negative Poisson’s ratio (auxetic structure) has better capabiliity to withstand compressive load and higher fracture toughness. Such structure may be a good candidate for shock absorption applications. The purpose of this study was to design different auxetic structures and to apply them for shoe midsole design. Dynamic finite element (FE) analysis was used to investigate the biomechanical effects of such cellular midsole structures on the foot during gait cycle. Three types of cellular, auxetic structures were designed and named: Type A, B and C structures with porosity ratios of 59%, 68% and 70% respectively. The FE models of the cellular structures were generated with both solid and beam elements by using HyperMesh pre-processing software. Then, LS-DYNA FE software was used to analyze the cellular structures under compression loading. The test specimens of the cellular structures were fabricated with TPU (Thermoplastic polyurethane) material by using a selective laser sintering 3D printer. The compressive mechanical properties of the cellular structure specimens were obtained by following the ASTM D3575-14 standards and were compared with the finite element analysis results. The shock absorption test of the cellular structures were also conducted with ASTM F1976-13 standard. In order to investigate the biomechanical effects of the cellular structure when used as shoe midsole, three different cellular pads were created using beam elements and then combined with a 3D finite element foot model for dynamic FE analysis during gait loadings. From the compression tests, the force-displacement results from the mechanical tests and FE analyses were compared. Pearson's correlation ratios in between the FE analysis results by using solid elements and beam elements were calculated for each of the three types of cellular structures. The correlation ratios showed that the mechanical properties were highly correlated among these three types and were all greater than 0.80. The energy absorption test values of Type A, B and C structures were 0.338 J, 0.485 J and 0.735 J, respectively. Therefore, Type C structure has the best shock absorption capability. The dynamic finite element analysis results showed that the peak plantar pressure during gait on the calcaneus area were 456.48 kPa, 417.72 kPa and 400.30 kPa, respectively. In the cellular structures analysis, it was demonstrated that the beam element model could effectively replace the solid element model and greatly reduce the analysis time. It was found that the Type C structure had the best shock absorption and plantar pressure reduction capabilities, the Type B structure had the best effect of stress distribution on the cellular structure during the dynamic gait cycle. In the present study, the complex cellular structures can be reasonably represented by simplified beam elements for finite element analysis. Also, the biomechanical characteristics of the foot using dynamic finite element analysis can be evaluated as well. This study can provide a useful reference for future studies on cellular structured midsole designs.

The overall aim of this research was to examine the factors that influence the coach-biomechanist relationship in the elite sprinting context and gain an understanding of the factors that impede and enhance performance environments and relationships. It is thought that the transfer of sport science research into coaching practice is not as efficient as it should be, as it has been established that coaches are not using sport science as a source of knowledge. Subsequently, this insufficient transfer of knowledge could be limiting potential improvements in athlete performance. Technique analysis is a common area of expertise for both sprint coaches and biomechanists in high-performance sport and was therefore the ideal context to explore the coach-biomechanist relationship in detail. The first phase of research examined the coach and biomechanists’ understandings of optimal sprint running technique and determined the relationships between the experiential knowledge of the two groups. Findings showed elements that are crucial to optimal sprinting technique, such as the position of the contact foot and extension of the leg during stance. Differences in knowledge between the two groups were complimentary. For example, the biomechanists’ focus on the transition from swing into stance phases and the coaches’ interest in upper body movement. Moreover, the communication of these knowledge differences was potentially problematic. The second phase of this research determined if the knowledge differences found in the first phase influenced the visual search patterns of coaches and biomechanists. This difference was not observed, with visual search behaviour not reflecting the differences in knowledge seen in phase one. The third phase aimed to establish the context in which coaches and biomechanists interact to improve performance. This phase supported previous phases’ results in that communication styles and knowledge differences were impeding factors and added lack of role clarity to this list. The fourth and final phase investigated the interactions and exchange of information that occurs during the technique assessment process. Results showed that the process is a coach-led partnership where rapport building, and equal sharing of knowledge are emphasised. In summary, this research contributes to the understanding of the coach-sport science relationship by providing practical evidence for numerous concepts in a novel and more specialized population. It increases our understanding of coach technical knowledge and visual perceptual behaviour as well as uniquely incorporating the sport biomechanists’ knowledge and perspective into these investigations. The multi-layered approach used allowed the knowledge, behaviours and interactions that comprise qualitative analysis of technique to be investigated. This has greatly improved our understanding of the coach- biomechanist relationship and the factors that impede and enhance it.

This study proposed a finite element procedure for protein normal mode analysis (NMA). The finite element model adopted the protein solvent-excluded surface to generate a homogeneous and isotropic volume. A simplified triangular approximation of coarse molecular surface was generated from the original surface model by using the Gaussian-based blurring technique. Similar to the widely adopted elastic network model, the finite element model holds a major advantage over standard all-atom normal mode analysis: the computationally expensive process of energy minimization that may distort the initial protein structure has been eliminated. This modification significantly increases the efficiency of normal mode analysis. In addition, the finite element model successfully brings out the capability of normal mode analysis in low-frequency/high collectivity molecular motion by capturing protein shape properties. Fair results from six protein models in this study have fortified the capability of the finite element model in protein normal mode analysis.