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Dissertations / Theses on the topic 'Biomechanika'
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1
Vosynek, Petr. "Deformačně-napěťová analýza povrchové náhrady kyčelního kloubu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-227873.
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Today is the surface hip repacement very often surgery becouse of new studies and improvements. For young and active people it's the best way to delay implantation of a total hip replacement. The objective of this study was to perform finite-element analyses of computational model of the partial/total surface replacement, conventional partial/total replacement and physiological hip joint. We obtained strain-stress states from these analyses. All results were compared one another and then were confronted with results of the physiological hip joint. The three-dimensional computational model consists of these components: sacral, pelvic and femoral bone, muscles, artificial socket, and surface hip replacement. We were using FEM system ANSYS. The geometrical models of bones were generated by means of computed tomography (CT) images. The FE model of bone reflects two types of the bone tissues (trabecular and cortical bone) and muscles which are important when standing on one leg. The model of the muscle corresponds to isometric contraction. The implants material and bone tissues were modelled as isotropic linear elastic material. The model was loaded by force, corresponding to load by standing on one leg.
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Bartoňová, Petra. "Analýza vlivu mechanických vlastností komponent patologické stěny tepny na její napjatost." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-418194.
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The thesis deals with measurements of the atherosclerothic carotid plaques mechanical properties with wiew towards the improvements of their constitutive models and then towards the impact of application of those constitutive models in fibrous cap. The introductory part provides a brief summary of medical knowledge needed to understand atheroma formation and the risks involved. Next, there's a survey of plaque mechanical testing methods and the obtained results on tissue properties. The previously used constitutive models of atherosclerothic tissues are listed as well. Main body of the thesis describes the preparation of testing samples from obtained atheroma, methodology and course of experiments execution and subsequent processing of the experimental data to evaluate the behavior of the atheromatous tissue individual parts. Then the discussion and evaluation of our results and findings is given. Along with the evaluated mechanical properties, experimental data fitted to models are presented with respect to their predictive abilities. The final part is dedvoted to the finite element analysis of an idealized 2D model with emphasis on the effect of necrotic core and fibrous tissue properties on von Mises equivalent stress in the fibrous cap.
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Lamrich, Martin. "Deformačně napěťová analýza femuru s vnitrodřeňovým hřebem a fixačními pásky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230513.
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The presented Master’s Thesis aims at determining stress and strain analysis of femur with fracture fixed by intramedullary nail and cerclage cable. The one of the goals of this work was create computational model which will be able simulate problem. Computational model consist of model of femur , it’s geometry was created on basis of CT data, than there was created model of intramedullary nail and cerclage cable on a basis of real objects. In this work was created simply model of femur with the same material features and characteristic proportions as analyzed model of femur. On this model was investigated direct impact of cerclage cables on deformation, respectively displacement in a surroundings of femoral fracture. On a final model were applied the real loads conditions. Preload in a cerclage cable was simulated by cooling down to a temperature from analytical calculation. Concluding analysis was powered by Finite Element Method (FEM) applied in system ANSYS Workbench 14.5 . Due to a results of analysis, we could say that using cerclage cables in combination with intramedullary nail is an effective way for healing femoral shaft fractures.
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Chladek, Wiesław. "System modelowania wybranych stanów mechanicznych żuchwy ludzkiej." Praca habilitacyjna, Wydawnictwo Politechniki Śląskiej, 2000. https://delibra.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=8063.
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Vostrejž, Jan. "Vliv moderních prvků pasivní bezpečnosti na ochranu posádky vozidla." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-232626.
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Thesis in the field of passive safety problems, traffic accidents and health outcomes of participants in road traffic accidents is aimed, inter alia, to create an overview of modern passive safety elements especially cars. The work deals with elements of the passive safety system and the impact on the crew vehicle. It describes the principle of operation, especially airbags, safety belts, belt pretensioner and it includes solution of limiters tensioning force in the safety belt and other elements that have the task of reducing the consequences of a traffic accident. The use of modern elements of passive safety provides increased protection for the crew and eliminates the formation injuries crew. The technical issue is therefore closely related to the healthcare industry and in particular the Court of medicine in the field of personal injury in relation to the types and characters of incidents, or by applying of the safety elements. There are also shown the actual road accidents in which were killed or injured members of crew with an analysis of the mechanism of injury with the use or non-use of safety elements.
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Janík, Rostislav. "Deformačně-napěťová analýza tepny s ateromem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443748.
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This master thesis analyses stress and strain of iliac artery with atheroma. Model of artery is created as 2D and symmetric about the y-axis. The first part of the thesis deals with a research, which includes obtaining information from medicine, which is necessary fort the right solution of the task. Next part dedicates to nonlinear mechanics, constitutive modeling from the view of biomechanice and computational modeling of arteries. In the next part is made analysis for load on artery by physiological and also by high blood pressure. In the end were specified uncertainties of the used model and evaluated chance of atherosclerotic plaque rupture.
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Koukal, Milan. "Mechanická analýza vlivu výrobních odchylek na styk hlavice a jamky totální endoprotézy kyčelního kloubu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-233902.
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In endoprosthesis surgery there are typically a high percentage of implant defects, these can lead to failure of the whole prosthesis. One type of total hip replacement function loss is acetabular cup loosening from the pelvic bone. This disertation examines manufacture perturbations as one of the possible reasons for this kind of failure. Both dimension and geometry manufacturing perturbations of ceramic head and polyethylen cup were analyzed. We find that perturbations in the variables analysed here affect considered values of contact pressure and frictional moment. Furthermore, contact pressure and frictional moment are quantities affecting replacement success and durability. From obtained results it can be recommended to fit head and cup with a clearance of between 0 mm and 0.05 mm. It can not be recommend using interference type of fit because of strong deterioration of the contact conditions. Roundness perturbation of ceramic head should not exceed 0.025 mm.
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Tulach, Pavel. "Pasivní bezpečnost vozidel se zaměřením na nekompatibilní nárazy." Doctoral thesis, Česká zemědělská univerzita v Praze, 2016. http://www.nusl.cz/ntk/nusl-259664.
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This dissertation describes in detail the issue of passive safety related to the biomechanics of injuries and crash tests processed as well.
Statistics of accidents for the last 10 years, which show the maximum and minimum numbers of accidents and fatalities, are presented in the first chapter, "Overview of the current state of solved problematice. There is also briefly defined legislative relationship between the driver, as road users on the one hand and vulnerable pedestrians on the other hand. The issue of injury biomechanics and especially the serious injuries of body parts (organs) are elaborated in relevant chapter.
Methodological part of the thesis described and analyzed data from previously crash tests and serve as a basis for comparison with other experimental tests. Other tests means tests performed on the shock chamber. After evaluation and processing of measured data is to identify and describe the limits of the load, which is the human body when exposed to incompatible impact.
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Kokot, Grzegorz. "Wyznaczanie własności mechanicznych tkanek kostnych z zastosowaniem cyfrowej korelacji obrazu, nanoindentacji oraz symulacji numerycznych." Praca habilitacyjna, Wydawnictwo Politechniki Śląskiej, 2013. https://delibra.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=19772.
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Ardatov, Oleg. "Apatinių galūnių įtvarų ilgaamžiškumo tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120726_163924-05619.
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Baigiamajame magistro darbe yra atliekamas apatinių galūnių įtvarų ilgaamžiškumo tyrimas. Yra iškeliama čiurnos sąnario įtvarų patvarumo problema ir sudaroma jos sprendimo metodika. Darbe yra atliekama čiurnos sąnario biomechanikos analizė, įtvarų konstrukcijų ir medžiagų analizė, nagrinėjama ilgaamžiškumo reikšmė ir tyrimo būdai. Sudaroma tyrimo metodika. Kompiuterinio modeliavimo būdu, panaudojant SolidWorks programinę įrangą, yra sudaromas įtvaro modelis, nustatomos veikiančios apkrovos, atliekami įtempių ir poslinkių pasiskirstymo tyrimai. Atliekami modelio nuovargio bandymai. Atsižvelgiant į tyrimų rezultatus, yra sudaromi įtvarų iš aukštos temperatūros plastikų tinkamo pritaikymo nurodymai. Pateikiamos išvados ir literatūros sąrašas.Final thesis presents the research of durability of lower limbs splints. The problem of fatigue behaviour of ankle joint splint is raised and its solution is suggested. Final thesis contains ankle joint biomechanics analysis, lower limbs splints design and material analysis. Review of durability research methods is also done. The methodology of research is arranged. Using the computer aided modeling with SolidWorks software the model of ankle joint splint is created. Load parameters are determined, research of stresses and deformations are performed. Fatigue test is also performed. Due to the results of research, the instructions for ankle joint splints made of high density polyethylene and polypropylene use and adaptation are listed. Final thesis also contains conclusions and list of literature. Size of work – 77 pages of text without attachments, 55 pictures, 9 tables and 25 bibliographical sources.
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Meisner, Patrik. "Použití fluidně-strukturní interakce u kmitajících lidských hlasivek." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443741.
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The presented thesis is involved in the biomechanics of phonation. The aim of the thesis is to set a fluid-structure interaction between the vocal folds and air flow when the pressure from lungs reaches the physiological values. In the expected outcome the self-oscillating vocal folds should be observable with characteristics shape-shift from convergent to divergent. In theory part of the thesis is described Anatomy of the vocal tract, physiology of the human phonation, research of computational simulations, experiments and visualisation methods are described in the theory part of the thesis. In the second part, setup of computational simulation with the finite element method is presented. Besides of the fluid-structure interaction the acoustical model is set. Achieved results are presented and compared to the results in literature. Displacements are evaluated from the structural model and pressures, velocities and flow velocities are evaluated from fluid model, so as acoustics results.
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Zapletal, Jakub. "Deformačně-napěťová analýza fixace kostí palce nohy." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-382569.
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This diploma thesis deals with analysis of the rigidity of different variations of foot fixations. In the thesis there is a description of elementary anatomy of foot and its patology. Furthermore the possible corrections of hallux deformities and chosen fixators are described. The problem of analysis is soluted by the method of finite elements. The thesis also includes steps of geometery model creation based on 3D scanning. Three differents types of fixations are compared in this thesis and each of them is created in two different levels of details. There is a comparation, analysis of final solutions and chosen influences on the rigidity in the conclusion.
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Konvalinka, Jan. "Deformačně napěťová analýza femuru s distrakčním intramedulárním hřebem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318846.
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This master's thesis is focused on determination and analysis of stress and strain in femur with distraction intramedullary nail for treating leg length discrepancy with the method of distraction osteogenesis. Thesis is mainly focused on states after distraction when the callus consolidates. Problem of determining stress and strain is solved by computational modeling using FEM. Detailed description of modeling is included in this thesis, complicated 3D geometry of bone was acquired from segmentation of CT images. Computational model is solve with 4 different types of callus geometry and also material properties of callus are varied. The influence on stress and strain when the middle distal screw is not applied is also analyzed.
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Yousefi, Koupaei Atieh. "Biomechanical Interaction Between Fluid Flow and Biomaterials: Applications in Cardiovascular and Ocular Biomechanics." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595335168435434.
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Jang, Sae, Rebecca R. Vanderpool, Reza Avazmohammadi, Eugene Lapshin, Timothy N. Bachman, Michael Sacks, and Marc A. Simon. "Biomechanical and Hemodynamic Measures of Right Ventricular Diastolic Function: Translating Tissue Biomechanics to Clinical Relevance." WILEY, 2017. http://hdl.handle.net/10150/626001.
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Background Right ventricular (RV) diastolic function has been associated with outcomes for patients with pulmonary hypertension; however, the relationship between biomechanics and hemodynamics in the right ventricle has not been studied. Methods and Results Rat models of RV pressure overload were obtained via pulmonary artery banding (PAB; control, n=7; PAB, n=5). At 3 weeks after banding, RV hemodynamics were measured using a conductance catheter. Biaxial mechanical properties of the RV free wall myocardium were obtained to extrapolate longitudinal and circumferential elastic modulus in low and high strain regions (E-1 and E-2, respectively). Hemodynamic analysis revealed significantly increased end-diastolic elastance (E-ed) in PAB (control: 55.1 mm Hg/mL [interquartile range: 44.785.4 mm Hg/mL]; PAB: 146.6 mm Hg/mL [interquartile range: 105.8155.0 mm Hg/mL]; P=0.010). Longitudinal E1 was increased in PAB (control: 7.2 kPa [interquartile range: 6.718.1 kPa]; PAB: 34.2 kPa [interquartile range: 18.144.6 kPa]; P=0.018), whereas there were no significant changes in longitudinal E-2 or circumferential E-1 and E-2. Last, wall stress was calculated from hemodynamic data by modeling the right ventricle as a sphere: (stress = Pressure x radius/2 x thickness Conclusions RV pressure overload in PAB rats resulted in an increase in diastolic myocardial stiffness reflected both hemodynamically, by an increase in E-ed, and biomechanically, by an increase in longitudinal E-1. Modest increases in tissue biomechanical stiffness are associated with large increases in E-ed. Hemodynamic measurements of RV diastolic function can be used to predict biomechanical changes in the myocardium.
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Houfek, Martin. "Návrh a vývoj experimentálního zařízení pro testování kloubní jamky TEP kyčelního kloubu a identifikace otěru pomocí optické metody." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-233946.
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Today is the implantation of joint replacements, although a radical, but very functional restoration frequent way ill joint. The implants are placed high demands on their biocompatible and long-term function, which is directly related to wear of joint replacements in the human body. Therefore, analysis of the complex behavior of the implant in the human body is a fundamental problem of biomechanics of implants. This issue is dedicated, this dissertation thesis. Dissertation thesis deals with the solution design and development of experimental device for testing the TEP acetabula and wear identification using optical method. The proposed device allows the joint burden hole TEP physiological manner, but by working with the acetabulum burdened by Power resultant joint axis passes through the hole. The physiological loading of articular wells and evaluating the size of the loss of polyethylene is currently intensively addressed. The results of this study may in the near future, serving as information for assessing the conduct of wear prosthetic hip joint in vivo. The work is devoted to solving the problem of the size required to detect the loss of polyethylene for joint replacement arthroplasty: Design and development of experimental equipment for testing the acetabulum of the hip joint arthroplasty. Identify wear using optical methods. Design and development of experimental equipment was made in the system Inventor Professional 2010 at the level of 3D modeling. Great attention was paid to the design fit into the acetabulum TEP testing machines and gripping the acetabulum into an optical device. Management options were tested with combinations of experimental equipment engines. Suggestions were made and then tests for fixing the acetabulum into an optical device. Has the possibility of depth analysis and identification of wear joined with innovative solutions to evaluate the loss of polyethylene acetabulum arthroplasty. Identification of abrasion (loss of polyethylene) joint arthroplasty holes were carried out experimental measurements using an optical holographic interferometry. The comprehensive analysis of the results of experimental measurement of the loss of polyethylene shows that this method can identify both the size but also an area where there is even to small changes in the surface, which depend on the abrasion. One can also say that using this method we are able to affect the will or displacements that affect the size of the loss of polyethylene in joint arthroplasty hole. Despite the number of known and lessons learned arising from the results of solving the problem of design and development of experimental equipment for testing the acetabulum and hip arthroplasty wear identification using optical methods, this work is that the initial study to identify problematics wear of joint replacements. Complete resolution of this issue is beyond the scope of one doctoral thesis.
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Bucci, Francesca. "Personalized biomechanical model of a patient with severe hip osteoarthritis for the prediction of pelvic biomechanics." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15879/.
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L’articolazione dell'anca è un'articolazione sinoviale sferica che costituisce la connessione primaria tra gli arti inferiori e lo scheletro della parte superiore del corpo. Durante le attività quotidiane di routine, carichi anormali ripetuti sull'anca possono portare alla danneggiamento della cartilagine articolare e conseguentemente , all’osteoartrite (OA).
L'OA dell'anca è una condizione muscolo-scheletrica cronica e progressiva, il cui trattamento per i pazienti severi è l'artroplastica totale dell'anca (THA). Il centro dell'articolazione dell'anca (HJC) ha grande importanza nell’analisi della biomeccanica dell’anca, così come il suo spostamento, che puo’ essere dovuto a patologie, come OA, o alla chirurgia, THA.
Per valutare la biomeccanica del bacino in questa tesi sono stati implementati un modello muscoloscheletrico (NMS) personalizzato statistical shape e modelli ad elementi finiti (FE) di un paziente con grave OA mono-laterale dell'anca.
Viene discussa l'accuratezza relativamente al modello scalato generico nella predizione delle grandezze biomeccaniche piu’ importanti, durante la deambulazione.
Attraverso i modelli FE, è stato studiato l'effetto di una cattiva stima e/o dello spostamento del centro dell'articolazione dell'anca nelle direzioni antero-posteriore, mediolaterale o infero-superiore per valutare lo stato di sollecitazione della pelvi.
Infine sono presentati i risultati di un approccio multiscala integrato, per valutare le caratteristiche biomeccaniche del suddetto paziente, passando dalla modellazione NMS, all’analisi del modello FE della pelvi, per effettuare un’analisi comparativa dell’arto osteoartritico con il modello dall’arto controlaterale prima dell’intervento e dopo lo stesso
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Denning, Matthew M. "The Effects of Aquatic Exercise on Physiological and Biomechanical Responses." DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/670.
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Due to recent advances in aquatic research, technology, and facilities, many modes of aquatic therapy now exist. These aquatic modes assist individuals (e.g., osteoarthritis patients) in the performance of activities that may be too difficult to complete on land. However, the biomechanical requirements of each aquatic therapy mode may elicit different physiological and functional responses. Therefore, the purpose of this thesis was to: (a) provide a review of the physiological and biomechanical differences between aquatic and land based exercises, and (b) examine the acute effects of underwater and land treadmill exercise on oxygen consumption (VO2), rating of perceived exertion (RPE), perceived pain, mobility, and gait kinematics for patients with osteoarthritis (OA). Methods consisted of the retrieval of experimental studies examining the physiological and biomechanical effects of deep water running (DWR), shallow water running (SWR), water calisthenics, and underwater treadmill therapy. The methods also examined the physiological and biomechanical effects on 19 participants during and after three consecutive exercise sessions on an underwater treadmill and on a land-based treadmill. Based on the studies reviewed, when compared to a similar land-based mode, VO2 values are lower during both DWR and SWR, but can be higher during water calisthenics and underwater treadmill exercise. RPE responses during DWR are similar during max effort, and stride frequency and stride length are both lower in all four aquatic modes than on land. Pain levels are no different between most water calisthenics, and most studies reported improvements in mobility after aquatic therapy, but no difference between the aquatic and land-based modes. The OA participants achieved VO2 values that were not different between conditions during moderate intensities, but were 37% greater during low intensity exercise on land than in water (p = 0.001). Perceived pain and Time Up & Go scores were 140% and 240% greater, respectively, for land than underwater treadmill exercise (p = 0.01). Patients diagnosed with OA may walk on an underwater treadmill at a moderate intensity with less pain and equivalent energy expenditures compared to walking on a land-based treadmill.
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Muschner, Anne. "Entwicklung eines Modells zur biomechanischen Untersuchung verschiedener Osteosynthesesysteme am Os scaphoideum." Doctoral thesis, Universitätsbibliothek Leipzig, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-82392.
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Die Kahnbeinfraktur ereignet sich als die häufigste Fraktur innerhalb der Handwurzelknochen. Als Pathomechanismus wird hauptsächlich der Sturz auf die nach dorsal hyperextendierte ulnar abduzierte Hand angesehen. Bei rechtzeitiger Diagnose und sofortiger Intervention lassen sich sehr gute Heilungsergebnisse erzielen und eine Pseudarthrosebildung verhindern. Für die akute dislozierte B2-Fraktur nach Herbert hat sich die intraossäre Fixation als bewährtes Behandlungs-verfahren etabliert. In der Klinik stehen dafür eine Vielzahl von intraossären Schrauben zur Verfügung, die sich in ihren technischen Eigenschaften teilweise stark unterscheiden. Ziel dieser Arbeit ist die Entwicklung eines biomechanischen Versuchsaufbaues, das im experimentellen Vergleich verschiedener Osteosynthese-verfahren am Os scaphoideum Anwendung finden soll. Die experimentell ermittelten Ergebnisse ermöglichen eine Aussage über die Primärstabilität, die allein durch die Verankerung des Implantats im Knochen erreicht wird.
In der hier vorliegenden in vitro Studie wurden sechs unversehrte anomaliefreie humane Kahnbeine der Hand, gestellt durch das Institut für Anatomie der Universitätsklinik Leipzig, vollständig von Bändern und umgebenden Weichteil-gewebe befreit. Zur Vermeidung eines Positionsverlustes beider Fragmentenden erfolgte zunächst die Osteosynthese durch Insertion einer Herbertschraube und anschließend die Osteotomie mittels oszillierender Knochensäge im Sinne einer nicht-dislozierten Fraktur im mittleren Drittel.
Die verwendete Herbertschraube der Firma Martin® war 21 mm lang und zählt zu den Standardimplantaten. Sie verfügt über zwei endständige Gewinde, die sich in Durchmesser und Gewindesteigung jeweils unterscheiden. Über einen Führungs-draht kann eine exakte Positionierung des kanülierten Implantats erreicht werden. Durch selbstbohrende und selbstschneidende Eigenschaften wird eine regelrechte Schraubenimplantation bei nur minimaler Knochensubstanzreduktion ermöglicht.
Die Knochen-Implantat-Verbindung wurde zweizeitig unter penibler Aussparung des Frakturspaltes in je 2 kubische eiserne Pfannen mit den Abmaßen 2,0 cm x 2,0 cm x 2,0 cm geklebt. Hierfür diente Sikadur®-31 CF Normal, ein lösemittelfreier, thixotroper Zweikomponentenkleber auf Epoxidharzbasis. In Zusammenarbeit mit der HTWK Leipzig erfolgte nach vollständiger Aushärtung der gesamten Testeinheit die Einspannung und Ausrichtung in die elektromechanische Prüfmaschine vom Typ LFM-H der Firma Walter + Bai AG. Zur Datenerhebung diente eine in den Versuchs-aufbau eingebrachte Kraftmessdose, die nach Einspannung des Testobjektes kalibriert wurde. An den beiden Eisenpfannen wurden zwei Branchen des Wegmess-systems platziert. Der Weg wurde als Regelgröße festgelegt. Die drei Kanäle speicherten 1-Zeitwerte, 2- Kraftwerte und 3- Wegwerte.
Wichtige Kriterien für das Design einer biomechanischen Studie sind das Einhalten standardisierter Bedingungen und die Reproduzierbarkeit der Ergebnisse. Nach Abschluss der Vorversuche und Auswertung der Ergebnisse ergaben sich folgende Erkenntnisse:
1) Zyklisch eingeleitete Kraft in Form von sinusförmigen Schwingungen ermöglichen eine standardisierte Verifizierbarkeit der Ergebnisse. Innerhalb dieser Studie wurde die Frequenz der wechselnden Belastungsrichtung auf 0,5 Hz festgelegt. Ein Belastungzyklus umfasste 100 sinusförmige Schwingungen.
2) Die Krafteinleitung soll über einen definierten Weg geschehen, damit Stadien vor dem definitiven Implantatversagen erfasst werden können.
3) Nach Abschluss eines Belastungszyklus soll die Auslenkung auf das nächsthöhere Belastungsniveau um einen definierten Weg erfolgen. Aus den Erkenntnissen des letzten Vorversuches profitierend wurde eine Auslenkungs-erhöhung um je 10 µm festgelegt.
4) Für die experimentelle Testung der Primärfestigkeit zwischen Os scaphoideum und intraossärem Implantat empfiehlt sich neben der exakten Schraubeninsertion eine Ausrichtung des Testkörpers entsprechend der Krafteinleitung, da somit ein Entstehen von Momenten innerhalb der Knochen-Implantat-Verbindung verhindert werden kann.
5) Damit in der biomechanischen in vitro Testung nur die Primärfestigkeit zwischen Knochen und Implantat gemessen wird, sollten die Versuche auf Zugbelastungen beruhen. Die Analyse des Kraftflusses im Versuchsaufbau ergab, dass während der Druckbelastung teilweise Kräfte gemessen worden sind, die keine Aussage über die Festigkeit der Knochen-Implantat-Verbindung erlauben. Darüber hinaus erwiesen sich die Druckversuche sogar als Ursache für ein schneller voranschreitendes Implantatversagen.
6) Die Verwendung einer Prüfmaschine ist für die komplexe Testung und die Auswertung der Ergebnisse empfehlenswert.
7) Die klinische Übertragbarkeit ist auf Grund des nicht berücksichtigten anatomisch funktionellen Zusammenwirkens mit angrenzendem Weichteil-gewebe und Knochen eingeschränkt.
Biomechanische Untersuchungen zur Primärstabilität können bei der Auswahl des „idealen“ Implantats hilfreich sein. Der direkte experimentelle Vergleich verschiedener intraossärer Schrauben und die Analyse ihrer technischen Eigenschaften können dazu beitragen, dass bei der Wahl des Implantats bessere Heilungserfolge in der operativen Versorgung der Kahnbeinfraktur erzielt werden und dass sich somit das Risiko einer Pseudarthrosenbildung vermindert.
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Matug, Michal. "Náhradní hlasivky pro generování zdrojového hlasu: Počítačové modelování funkce hlasivek." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-234251.
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This doctoral thesis focuses on computational modelling of human vocal folds and vocal tract functions using finite element method (FEM). Human voice is crucial in human communication. Therefore one of the main targets of current medicine is creation of artificial vocal folds, which would substitute the original vocal folds. The computational modelling can be used to understand principles of voice production, determination of parameters that the artificial vocal folds have to meet and verification of their functionality. First part of this thesis focuses on modelling of human voice creation by whisper. Influence of intraglottal gap on eigenvalues distribution for individual vowels was analysed using FEM vocal tract and trachea model. Further there is presented two-dimensional (2D) finite element model of the flow-induced self-oscillation of the human vocal folds in interaction with acoustic spaces of the vocal tract. The 2D vocal tract model was created on the basis of converting the data from magnetic resonance images (MRI). Explicit coupling scheme with separated solvers for structure and fluid domain was used for modelling of the fluid-structure interaction. Created computational model comprises: large deformations of the vocal folds tissue, contact between vocal folds, fluid-structure interaction, morphing the fluid mesh according to the vocal-fold motion (Arbitrary Lagrangian-Eulerian approach), unsteady viscous compressible or incompressible airflow described by the Navier-Stokes equations and airflow separation during glottis closure. This model is used to analyse the influence of stiffness and damping changes in individual vocal fold tissue layers (in particular in superficial lamina propria). Part of this computational analysis is also comparison of vocal folds behaviour for compressible and incompressible flow model. Videokymograms (VKG) are subsequently created from obtained results of FEM calculations which enable to compare individual variants between themselves and with motion of real human vocal folds. In next part of this thesis is presented three-dimensional (3D) finite element model of the flow-induced self-oscillation of the human vocal folds. This 3D model was created from a previous 2D model by extrude to the third direction. Using this model was again compared influence of compressible and incompressible flow model on vocal folds motion and generated sound by using videokymograms and acoustic spectra. The last part of this thesis focuses on the possibility to replace missing natural source voice in form reed-based element. Behaviour of reed-based element was analysed using computational modelling and using measurements on experimental physical model. The physical model enables changes in setting gap between reed and reed stop and performing acoustical and optical measurements.
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Ryšavý, Antonín. "Výpočtové modelování šíření hlasu okolo hlavy člověka pomocí metody konečných prvků." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-382562.
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In the first part of this master's thesis there is briefly presented the biomechanics of the human voice creation and an overview of the hitherto published computational models of the vocal tract and dissemination of the acoustic waves around the human head. The second part of the thesis deals with the creation of the computational model of a dissemination of the acoustic waves through vocal tract and further into a space around the head during the pronouncing of the Czech vowel /a:/. The vocal tract is excited by a harmonic signal in the place of vocal chords. On the surface of the vocal tract and the part of the head including hair and skin there is defined an acoustic absorption. The dissemination of the acoustic waves in the vocal tract, in the near field around the mouth, in the area around the head and in the points on the cheeks is detailed mapped. The dissemination of the acoustic waves is analyzed in the points where the speech microphones are placed. Acoustic pressure dependence on frequency, transmission functions between defined points and the acoustic pressure amplitudes depending on the distance from the mouth are obtained. In particular, the frequency distortion of the spectra is observed at the points indicated. Furthermore, the radiation impedance in the mouth area is evaluated. The results obtained are compared with the results of the hitherto published experimental measurements and can be used for the exact measurement of human voice or for the frequency correction of the microphones during the scann of the speech and sing placced in the analyzed points.
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Wolański, Wojciech. "Modelowanie i prognozowanie zmian morfologii głowy dziecka." Praca habilitacyjna, Wydawnictwo Politechniki Śląskiej, 2015. https://delibra.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=68439.
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Orekhov, Greg. "Hip and Knee Biomechanics for Transtibial Amputees in Gait, Cycling, and Elliptical Training." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/2010.
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Transtibial amputees are at increased risk of contralateral hip and knee joint osteoarthritis, likely due to abnormal biomechanics. Biomechanical challenges exist for transtibial amputees in gait and cycling; particularly, asymmetry in ground/pedal reaction forces and joint kinetics is well documented and state-of-the-art passive and powered prostheses do not fully restore natural biomechanics. Elliptical training has not been studied as a potential exercise for rehabilitation, nor have any studies been published that compare joint kinematics and kinetics and ground/pedal reaction forces for the same group of transtibial amputees in gait, cycling, and elliptical training. The hypothesis was that hip and knee joint kinematics and kinetics and ground and pedal reaction forces would differ due to exercise (gait, cycling, elliptical) amputee status (amputated, control [non-amputated]), and leg (dominant [intact], non-dominant [amputated]). Ten unilateral transtibial amputees and ten control participants performed the three exercises while kinematic and kinetic data were collected. Hip and knee joint flexion angle, resultant forces, and resultant moments were calculated by inverse dynamics for the dominant and non-dominant legs of both participant groups. Joint biomechanics and measured ground/pedal reaction forces were then compared between exercises, between the dominant and non-dominant legs within each participant group, and across participant groups. Significant differences in hip and knee joint flexion angles and timing, compressive forces, extension-flexion (EF) and adduction-abduction (AddAbd) moments, and anterior-posterior (AP) and lateral-medial (LM) reaction forces were found. Particularly, transtibial amputees showed maximum knee flexion angle asymmetry as compared to controls in all three exercises. Maximum hip and knee compressive forces, EF moments, and AddAbd moments were lowest in cycling and highest in gait. Asymmetry in amputee midstance knee flexion and timing in v gait, coupled with low maximum EF moment for the non-dominant leg, suggests that amputees avoid contraction of the non-dominant quadriceps muscle. Knee flexion angle and EF moment asymmetry in elliptical training suggests that a similar phenomenon occurs. Asymmetry in AP and LM reaction forces in gait, but not other exercises, suggests that exercises that constrain kinematics reduce loading imbalances. The results suggest that cycling and elliptical training should be recommended to transtibial amputees for rehabilitation due to reduced hip and knee joint forces and moments. Elliptical training may be preferred over gait due to decreased joint loading and loading asymmetry, but some asymmetry and differences from control participants still exist. Non-weight bearing exercises such as cycling may be best at reducing overall joint loading and joint load asymmetry but do not eliminate all kinematic and temporal asymmetries. Current state-of-the-art prosthetic leg design is insufficient in restoring natural biomechanics not only in gait but also in cycling and elliptical training. Improved prosthesis kinematics that restore non-dominant knee flexion in amputees to normal levels could help reprogram quadriceps muscle patterns in gait and elliptical training and hip and knee joint biomechanical asymmetries. Further work in comparing contralateral and prosthesis ankle joint biomechanics would help to elucidate the relationship between prosthesis design and its impact on lower limb joint biomechanics.
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Gutierrez-Franco, Juan. "THE EFFECTS OF OBESITY ON RESULTANT KNEE JOINT LOADS FOR GAIT AND CYCLING." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1624.
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Osteoarthritis (OA) is a degenerative disease of cartilage and bone tissue and the most common form of arthritis, accounting for US$ 10.5 billion in hospital charges in 2006. Obesity (OB) has been linked to increased risk of developing knee OA due to increased knee joint loads and varus-valgus misalignment. Walking is recommended as a weight-loss activity but it may increase risk of knee OA as OB gait increases knee loads. Cycling has been proposed as an alternative weight-loss measure, however, lack of studies comparing normal weight (NW) and OB subjects in cycling and gait hinder identification of exercises that may best prevent knee OA incidence. The objective of this work is to determine if cycling is a better weight-loss exercise than gait in OB subjects as it relates to knee OA risk reduction due to decreased knee loads. A stationary bicycle was modified to measure forces and moments at the pedals in three dimensions. A pilot experiment was performed to calculate resultant knee loads during gait and cycling for NW (n = 4) and OB (n = 4) subjects. Statistical analyses were performed to compare knee loads and knee angles, and to determine statistical significance of results (p < 0.05). Cycling knee loads were lower than gait knee loads for all subjects (p < 0.033). OB axial knee loads were higher than NW axial knee loads in gait (p = 0.004) due to the weight-bearing nature of gait. No differences were observed in cycling knee loads between NW and OB subjects, suggesting cycling returns OB knee loads and biomechanics to normal levels. The lack of significant results in cycling could be due to the small sample size used or because rider weight is supported by the seat. Limitations to this study include small sample size, soft tissue artifact, and experimental errors in marker placement. Future studies should correct these limitations and find knee joint contact force rather than knee resultant loads using v EMG-driven experiments. In conclusion, cycling loads were lower than gait loads for NW and OB subjects suggesting cycling is a better weight-loss exercise than gait in the context of reducing knee OA risk.
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Reinert, Senia Smoot. "Enhancing Posturography Stabilization Analysis and Limits of Stability Assessment." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1470227622.
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Mandaltsi, Aikaterini. "Modelling the mechanobiological evolution of aneurysms : an integrative in vivo, in vitro and in silico approach." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:08d7dde3-2501-4bb4-a229-40225f75efec.
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In silico models of intracranial aneurysm (IA) evolution aim to reliably represent the mechanical blood flow environment, the biology of the arterial wall and, crucially, the complex link between the two, namely the mechanobiology of healthy and diseased arteries. The ultimate goal is to create diagnostic tools for personalized management and treatment of aneurysm disease. Towards that target, the work presented in this thesis aims to establish a directly interactive link between experimental (in vivo and in vitro) and computational work for biologically and clinically relevant research on aneurysm disease. Mechanobiological hypotheses were firstly investigated in a novel 1D mathematical conceptual model of aneurysm evolution: for the first time these included representations of endothelial heterogeneity and smooth muscle cell (SMC) active stress response and apoptosis. The 1D investigations analysed and assessed the role of wall shear stress (WSS) homeostasis in elastin degradation, and the evolving role of the adventitia as a protective sheath in health and primary load-bearer in disease. The 1D framework was applied to a specific patient's aneurysm using both imaging and histological data to parameterise the model, calculating a material parameter for the adventitital collagen. The predicted evolution captured aspects of tissue changes measured with time focusing on the remodelled tissue wall thickness consistent with the experimental measurements, and physiological cyclic deformation in order to propose an approach to modelling adventitia's adaptive role to load bearing. Furthermore, an existing Fluid-Solid-Growth (FSG) computational framework was adapted and calibrated for the same patient-specific case with the help from the experimental data and the analysis from the 1D framework. This FSG model quantifies the arterial mechanical environment and captures the mechanical response of the fibrous arterial constituents. Comparing 1D and 3D investigations to establish consistency for our models, the 3Dmodel tested the hypothesis of WSS homeostasis, additionally introducing the element of spatial heterogeneity in the definition, and a new hypothesis linking cyclic deformation with collagen growth that ensures a physiological mechanical environment in stabilised aneurysms. Moreover, the FSG framework was applied in a specific rabbit aneurysm case and extended to link growth and remodeling to the detailed representation of the pulsatile blood flow mechanical environment. This research illustrates the power of computational modelling when coupled with rich data sets on the physiology, histology and geometry of healthy and diseased vascular tissue. In particular, the integrative modelling framework provides the foundation for establishing mechanobiological links crucial to aneurysm progression, and a basis for further research towards creating reliable aneurysm clinical tools.
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Bansod, Yogesh Deepak. "Computational Simulation of Mechanical Tests of Isolated Animal Cells." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-263397.
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Buňka tvoří složitý biologický systém vystavený mnoha mimobuněčným mechanickým podnětům. Hlubší pochopení jejího mechanického chování je důležité pro charakterizaci její odezvy v podmínkách zdraví i nemoci. Výpočtové modelování může rozšířit pochopení mechaniky buňky, která může přispívat k vytvoření vztahů mezi strukturou a funkcí různých typů buněk v různých stavech. Za tímto účelem byly pomocí metody konečných prvků (MKP) vytvořeny dva bendotensegritní modely buňky v různých stavech: model vznášející se buňky pro analýzu její globální mechanické odezvy, jako je protažení nebo stlačení, a model buňky přilnuté k podložce, který vysvětluje odezvu buňky na lokální mechanické zatížení, jako třeba vtlačování hrotu při mikroskopii atomárních sil (AFM). Oba zachovávají základní principy tensegritních struktur jako je jejich předpětí a vzájemné ovlivnění mezi komponentami, ale prvky se mohou nezávisle pohybovat. Zahrnutí nedávno navržené bendotensegritní koncepce umožňuje těmto modelům brát v úvahu jak tahové, tak i ohybové namáhání mikrotubulů (MTs) a také zahrnout vlnitost intermediálních filament (IFs). Modely předpokládají, že jednotlivé složky cytoskeletu mohou měnit svůj tvar a uspořádání, aniž by při jejich odstranění došlo ke kolapsu celé buněčné struktury, a tak umožňují hodnotit mechanický příspěvek jednotlivých složek cytoskeletu k mechanice buňky. Model vznášející se buňky napodobuje realisticky odezvu síla-deformace během protahování a stlačování buňky a obě odezvy ilustrují nelineární nárůst tuhosti s růstem mechanického zatížení. Výsledky simulací ukazují, že aktinová filamenta i mikrotubuly hrají klíčovou úlohu při určování tahové odezvy buňky, zatímco k její tlakové odezvě přispívají podstatně jen aktinová filamenta. Model buňky přilnuté k podložce dává odezvu síla-hloubka vtlačení ve dvou různých místech odpovídající nelineární odezvě zjištěné experimentálně při AFM. Výsledky simulací ukazují, že pro chování buňky je rozhodující místo vtlačení a její tuhost určují aktinová povrchová vrstva, mikrotubuly a cytoplazma. Navržené modely umožňují cenný vhled do vzájemných souvislostí mechanických vlastností buněk, do mechanické úlohy komponent cytoskeletu jak individuálně, tak i ve vzájemné synergii a do deformace jádra buňky za různých podmínek mechanického zatížení. Tudíž tato práce přispívá k lepšímu pochopení mechaniky cytoskeletu zodpovědné za chování buňky, což naopak může napomáhat ve zkoumání různých patologických podmínek jako je rakovina a cévní choroby.
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Wetzel, Franziska. "Biomechanical Phenotyping of Cells in Tissue and Determination of Impact Factors." Doctoral thesis, Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-144866.
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Diese Arbeit beinhaltet Ergebnisse der ersten klinischen Studie zur Charakterisierung der mechanischen Eigenschaften von Zellen in einem Tumor mit der dafür notwendigen Probengröße. Dies ermöglichte die Erstellung eines umfassenden Bildes von Subpopulationen innerhalb eines Tumors mit großem diagnostischem Potential. Die Änderung der Einzelzellmechanik von Tumorzellen wird durch Veränderung des Zytoskeletts, einem komplexes Polymernetzwerk in Zellen, hervorgerufen. Mit Hilfe von Zellgiften wurde das Zytoskelett gezielt manipuliert, um den Einfluss einzelner Faktoren auf die Biomechanik zu bestimmen.
Aus Gewebeproben von Brustkrebspatienten wurden Zellen mit Hilfe enzymatischer Aufspaltung des extrazellulären Kollagennetzwerkes isoliert. Als Kontrollsystem wurden Primärzellen aus Brustreduktionsgewebe und aus Fibroadenomen, gutartigen Gewebeneubildungen der Brustdrüse, verwendet. Unter Einsatz des Optischen Stretchers, einer Zweistrahl-Laserfalle, wurden suspendierte Zellen für zwei Sekunden einer konstanten Zugspannung ausgesetzt und das Deformations- wie auch das anschließende Relaxationsverhalten beobachtet.
Dabei ergaben sich wesentliche Unterschiede zwischen Tumor- und Kontrollproben. Neben Zellen mit ähnlichen Steifigkeiten, enthielten Tumorproben Subpopulationen sehr weicher Zellen, wie sie in Normalgewebe nicht zu finden sind. Desweiteren war das Relaxationsverhalten der Tumorzellen stärker elastisch dominiert. Einzelne Zellen kontrahierten sogar aktiv gegen die Zugspannung. Versuche, das Zytoskelett mittels Zellgiften künstlich in einem Zustand zu bringen, der in Krebszellen beobachtet wurde, ergaben zwar ebenfalls die Zunahme weicherer Zellen, jedoch war das Relaxationsverhalten eher viskos dominiert. Fluoreszenzaufnahmen des Aktin-Zytoskeletts sowie der fokalen Adhäsionen, die das Aktin-Netzwerk der Zelle mit dem Substrat verankern, zeigten Veränderungen bei Krebszellen im Vergleich zu Kontrollen.
Darüber hinaus wurden Einflussfaktoren auf die Zellmechanik untersucht. Neben Kulturbedingungen, beeinflussen auch Alter und Medikation das biomechanische Verhalten. Die Steifigkeit der Krebszellen scheint vom Ursprungsgewebe beeinflusst zu werden, sodass Zellen verschiedener Krebsarten Steifigkeiten in unterschiedlichen Regimes zeigen.
Die Ergebnisse dieser Arbeit liefern wichtige Informationen für unser Verständnis der Karzinogenese und bilden die Grundlage für eine neue diagnostische Methode zur Bestimmung der Tumoraggressivität. Eine gezielte Untersuchung der gefundenen Subpopulationen in einem Tumor könnte dabei helfen, neue Therapieansätze zu entwickeln und damit die hohen Rezidivraten aggressiver Tumore zu vermindern.
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Skaro, Jordan M. "Knee Angles and Axes Crosstalk Correction In Gait, Cycling, and Elliptical Training Exercises." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1922.
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When conducting motion analysis using 3-dimensional motion capture technology, errors in marker placement on the knee results in a widely observed phenomenon known as “crosstalk” [1-18] in calculated knee joint angles (i.e., flexion-extension (FE), adduction-abduction (AA), internal-external rotation (IE)). Principal Component Analysis (PCA) has recently been proposed as a post hoc method to reduce crosstalk errors and operates by minimizing the correlation between the knee angles [1, 2]. However, recent studies that have used PCA have neither considered exercises, such as cycling (C) and elliptical training (E), other than gait (G) nor estimated the corrected knee axes following PCA correction. The hypothesis of this study is that PCA can correct for crosstalk in G, C, and E exercises but that subject-specific PCA corrected axes differ for these exercises.
Motion analysis of the selected exercises were conducted on 8 normal weight (body mass index (BMI) = 21.70 +/- 3.20) and 7 overweight participants (BMI = 27.45 +/- 2.45). An enhanced Helen Hayes marker set with 27 markers was used to track kinematics. Knee joint FE, AA, and IE angles were obtained with Cortex (Motion Analysis, Santa Rosa, CA) software and corrected using PCA to obtain corrected angles for each exercise. Exercise-specific corrected knee joint axes were determined by finding axes that reproduced the shank and ankle body vectors taken from Cortex when used with the PCA corrected angles. Then, PCA corrected gait axes were used as a common set of axes for all exercises to find corresponding knee angles. Paired t-tests assessed if FE-AA angle correlations changed with PCA. Multivariate Paired Hotelling’s T-Square tests assessed if the PCA corrected knee joint axes were similar between exercises. ANOVA was used to assess if Cortex angles, PCA corrected angles, and knee angles using PCA corrected gait axes were different.
Reduced FE-AA angle correlations existed for G (p<0.001 for Cortex and p=0.85 for PCA corrected), C (p=0.01 for Cortex and p=0.77 for PCA corrected), and E (p<0.001 for Cortex and p=0.77 for PCA corrected). Differences in the PCA corrected knee axes were found between G and C (p<0.0014). Then, differences were found between Cortex, PCA corrected, and C and E knee angles using the PCA corrected G axes (p<0.0056).
The results of this study suggest that if PCA is used to reduce crosstalk errors in motions other than G then it is recommended to adopt the use of a PCA corrected axes set determined from G to produce the PCA corrected angles.
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Said, Munzir. "Computational optimal control modeling and smoothing for biomechanical systems." University of Western Australia. Dept. of Mathematics and Statistics, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0082.
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[Truncated abstract] The study of biomechanical system dynamics consists of research to obtain an accurate model of biomechanical systems and to find appropriate torques or forces that reproduce motions of a biomechanical subject. In the first part of this study, specific computational models are developed to maintain relative angle constraints for 2-dimensional segmented bodies. This is motivated by the fact that there is a possibility of models of segmented bodies, moving under gravitational acceleration and joint torques, for its segments to move past the natural relative angle limits. Three models to maintain angle constraints between segments are proposed and compared. These models are: all-time angle constraints, a restoring torque in the state equations and an exponential penalty model. The models are applied to a 2-D three segment body to test the behaviour of each model when optimizing torques to minimize an objective. The optimization is run to find torques so that the end effector of the body follows the trajectory of a half circle. The result shows the behavior of each model in maintaining the angle constraints. The all-time constraints case exhibits a behaviour of not allowing torques (at a solution) which make segments move past the constraints, while the other two show a flexibility in handling the angle constraints more similar to a real biomechanical system. With three computational methods to represent the angle contraint, a workable set of initial torques for the motion of a segmented body can be obtained without causing integration failure in the ordinary differential equation (ODE) solver and without the need to use the “blind man method” that restarts the optimal control many times. ... With one layer of penalty weight balancing between trajectory compliance penalty and other optimal control objectives (minimizing torque/smoothing torque) already difficult to obtain (as explained by the L-curve phenomena), adding the second layer penalty weight for the closeness of fit for each of the body segments will further complicate the weight balancing and too much trial and error computation may be needed to get a reasonably good set of weighting values. Second order regularization is also added to the optimal control objective and the optimization has managed to obtain smoother torques for all body joints. To make the current approach more competitive with the inverse dynamic, an algorithm to speed up the computation of the optimal control is required as a potential future work.
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Schmidt, Sebastian, Tobias Kießling, Enrico Warmt, Anatol Fritsch, Roland Stange, and Josef A. Käs. "Complex thermorheology of living cells." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-173543.
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Temperature has a reliable and nearly instantaneous influence on mechanical responses of cells. As recently published, MCF-10A normal epithelial breast cells follow the time-temperature superposition (TTS) principle. Here, we measured thermorheological behaviour of eight common cell types within physiologically relevant temperatures and applied TTS to creep compliance curves. Our results showed that superposition is not universal and was seen in four of the eight investigated cell types. For the other cell types, transitions of thermorheological responses were observed at 36 °C. Activation energies (EA) were calculated for all cell types and ranged between 50 and 150 kJ mol-1. The scaling factors of the superposition of creep curves were used to group the cell lines into three categories. They were dependent on relaxation processes as well as structural composition of the cells in response to mechanical load and temperature increase. This study supports the view that temperature is a vital parameter for comparing cell rheological data and should be precisely controlled when designing experiments.
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Salinas, Manuel. "Movement Effects on the Flow Physics and Nutrient Delivery in Engineered Valvular Tissues." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1924.
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Mechanical conditioning has been shown to promote tissue formation in a wide variety of tissue engineering efforts. However the underlying mechanisms by which external mechanical stimuli regulate cells and tissues are not known. This is particularly relevant in the area of heart valve tissue engineering (HVTE) owing to the intense hemodynamic environments that surround native valves. Some studies suggest that oscillatory shear stress (OSS) caused by steady flow and scaffold flexure play a critical role in engineered tissue formation derived from bone marrow derived stem cells (BMSCs). In addition, scaffold flexure may enhance nutrient (e.g. oxygen, glucose) transport. In this study, we computationally quantified the i) magnitude of fluid-induced shear stresses; ii) the extent of temporal fluid oscillations in the flow field using the oscillatory shear index (OSI) parameter, and iii) glucose and oxygen mass transport profiles. Noting that sample cyclic flexure induces a high degree of oscillatory shear stress (OSS), we incorporated moving boundary computational fluid dynamic simulations of samples housed within a bioreactor to consider the effects of: 1) no flow, no flexure (control group), 2) steady flow-alone, 3) cyclic flexure-alone and 4) combined steady flow and cyclic flexure environments. We also coupled a diffusion and convention mass transport equation to the simulated system. We found that the coexistence of both OSS and appreciable shear stress magnitudes, described by the newly introduced parameter OSI-t , explained the high levels of engineered collagen previously observed from combining cyclic flexure and steady flow states. On the other hand, each of these metrics on its own showed no association. This finding suggests that cyclic flexure and steady flow synergistically promote engineered heart valve tissue production via OSS, so long as the oscillations are accompanied by a critical magnitude of shear stress. In addition, our simulations showed that mass transport of glucose and oxygen is enhanced by sample movement at low sample porosities, but did not play a role in highly porous scaffolds. Preliminary in-house in vitro experiments showed that cell proliferation and phenotype is enhanced in OSI-t environments.
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Jennings, Dalton James. "USE OF BODY COMPOSITION IMAGING TO CALCULATE 3-D INERTIAL PARAMETERS FOR INVERSE DYNAMIC ANALYSIS OF YOUTH PITCHING ARM KINETICS." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2122.
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The objectives of this study were to 1) calculate participant-specific segment inertial parameters using dual energy X-ray absorptiometry (DXA) data (referred to as full DXA-driven parameters) and compare the pitching arm kinetic predictions using full DXA-driven inverse dynamics vs scaled, DXA mass-driven (using DXA masses but scaled centers of mass and radii of gyration), and DXA scaled inverse dynamics(ID) (using the full DXA-driven inertial parameters averaged across all participants), 2) examine associations between full DXA-driven kinetics and body mass index (BMI) and 3) examine associations between full DXA-driven kinetics and segment mass index (SMI). Eighteen 10- to 11- year-olds pitched 10 fastballs. DXA scans were conducted and examined to obtain 3D inertial parameters of the upper arm, forearm, and hand. Full DXA-driven and scaled inertial parameters were compared using paired t-tests. Pitching arm kinetic predictions calculated with the four methods (i.e. scaled ID, DXA mass-driven ID, full DXA-driven ID, and DXA scaled ID) were compared using a repeated measures ANOVA with Tukey post-hoc tests. The major results were that 1) full DXA-driven participant specific inertial parameters differed from scaled inertial parameters 2) kinetic predictions significantly varied by method and 3) full DXA-driven ID predictions for shoulder compression force and shoulder internal rotation torque were significantly associated with BMI and/or SMI.
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Koehler, Amy. "Biomechanical Modeling of Manual Wheelchair Propulsion:Force Capability Investigation for Improved Clinical Fitting Procedures." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1494193078750548.
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Schöne, Martin. "Possibilities of Articular Cartilage Quantification Based on High-Frequency Ultrasound Scans and Ultrasound Palpation." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21781.
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In der Diagnostik und Reparatur von hyalinem Gelenkknorpel sind neue Methoden zur Quantifizierung von Struktur und mechanischer Belastbarkeit gefragt, um die Behandlung von Knorpelschäden an Millionen von Patienten weltweit zu verbessern.
Mittels hochfrequentem, fokussierten Ultraschall werden Oberflächenparameter für Reflektivität und Rauheit an Gelenkknorpel bestimmt. Es wird gezeigt wie die Oberflächenneigung kontrolliert werden kann. Die Ergebnisse vermitteln ein besseres Verständnis über die Zusammensetzung der Ultraschallsignale aus reflektierten und gestreuten Komponenten.
3D Ultraschallscans von Knorpelregeneraten erlauben die Defektstellen volumetrisch zu Quantifizieren. Die Proben wurden zusätzlich nach etablierten Bewertungssystemen benotet, welche auf makroskopischer Beurteilungen, MRT-Scans und Histologie basieren. Die ultraschallbasierten Volumendaten zeigten dabei gute Korrelationen mit den Punktwertungen.
Die im Labor verwendeten Messaufbauten zur biomechanischen Charakterisierung von Gelenkknorpel können am Patienten nicht angewandt werden. Daher können Ärzte die Festigkeit von Knorpel bisher nur mittels manueller Palpation abschätzen. Diese Arbeit entwickelt eine Methode der Ultraschall-Palpation (USP), die es erlaubt, die während der manuellen Palpation erzeugte Kraft und Deformation, basierend auf Ultraschallechos, aufzunehmen. Es wurde einen Prototyp entwickelt womit gezeigt werden konnte, dass USP eine ausreichende Genauigkeit und Reproduzierbarkeit aufweist. Wiederholte Messungen können zusätzlich zeitabhängige biomechanische Parameter von Knorpel ableiten.
Zusammenfassend zeigt diese Arbeit verbesserte und neue Möglichkeiten zur strukturellen und biomechanischen Charakterisierung von hyalinem Gelenkknorpel bzw. den Ergebnissen von Knorpelreparatur basierend auf Ultraschalldaten. Diese Methoden haben das Potenzial die Diagnostik von Gelenkknorpel und die Quantifizierung von Knorpelreparatur zu verbessern.In the diagnostics and repair of hyaline articular cartilage, new methods to quantify structure and mechanical capacity are required to improve the treatment of cartilage defects for millions of patients worldwide. This thesis uses high frequency focused ultrasound to derive surface parameters for reflectivity and roughness from articular cartilage. It is shown how to control the inclination dependency to gain more reliable results. Furthermore, the results provided a better understanding of the composition of ultrasonic signals from reflected and scattered components. 3D ultrasound scans of cartilage repair tissue were performed to quantify defect sites after cartilage repair volumetrically. The samples were also graded according to established scoring systems based on macroscopic evaluation, MRI scans and histology. The ultrasound-based volumetric parameters showed good correlation with these scores. Complex biomechanical measurement setups used in laboratories cannot be applied to the patient. Therefore, currently physicians have to estimate the stiffness of cartilage by means of manual palpation. In the last part of this thesis, a method denoted as ultrasound palpation is developed, which allows for measuring the applied force and strain during manual palpation in real time, solely based on the evaluation of the time of flight of ultrasound pulses. A prototype was developed and its measurement accuracy and reproducibility were characterized. It could be shown that ultrasound palpation has sufficient accuracy and reproducibility. Additionally, by repeated measurements it was possible to derive time-dependent biomechanical parameters of cartilage. In summary, this work shows improved and new possibilities for structural and biomechanical characterization of hyaline articular cartilage and the outcomes of cartilage repair based on ultrasound data. The methods have the potential to improve the diagnostics of articular cartilage and quantification of its repair.
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Stewart, Kevin Matthew. "MECHANICAL SIMULATION OF ARTICULAR CARTILAGE BASED ON EXPERIMENTAL RESULTS." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/93.
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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.
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Kuchařová, Lenka. "Biomechanika reflexní lokomoce." Master's thesis, 2008. http://www.nusl.cz/ntk/nusl-291449.
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Biomechanics of reflex locomotion - electromyographic analysis author: Lenka Kuchařová summary: Vojta method is not yet in the professional world fully accepted, especially for the lack of conclusive studies that corroborate the veracity of theoretical postulates. Work on the basis of the analysis of the recording electromyographic (SEMG) in time and frequency Domain confirmed the muscle activity in the therapy of reflex locomotion. He pointed to the importance of the initial position of reflective patterns. The work outlined further directions of research, which should lead to the elucidation of the neurophysiological mechanisms of action of this method. Keywords: reflex locomotion, trigger zones, surface electromyography, frequency analysis Powered by TCPDF (www.tcpdf.org)
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Stošek, Zdeněk. "Biomechanika cév a cévních náhrad." Master's thesis, 2006. http://www.nusl.cz/ntk/nusl-271860.
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Mechanical properties of vessel walls influence many physiological functions of organisms and its health status. Biomechanical changes in mechanical properties of vessels accompany process of aging. Consequently, biomechanical characteristics may be marker of aging. Aim of this work was identification of biomechanical characteristics of pig aorta walls on the basis of measurement of impulse and transient mechanical responses of deformation on stress. Work also analyzed linearity of parameters. Measurements were performed by instruments developed on department of biophysics and physical chemistry.
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Svatoš, Václav. "Biomechanika šlapání jako předpoklad výkonu v cyklistické části triatlonu." Master's thesis, 2012. http://www.nusl.cz/ntk/nusl-308018.
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Tittle: Biomechanics of pedaling as a determinant for the performance in the cycling part in the triathlon Objective: Prove that mastering pedaling technique, means higher performance in triathlon. Method: For the analysis of measured data use software SPSS, in which we use the test for two independent (paired) files. Due to the characteristics of the file, we used the Mann- Whitney test, we set the significance level at 0.05. Then we set standards for the selected test using T-points. Results: On the basis of the hypotheses, we conclude that there satisticky significant difference between groups (selection, other) the test results in the men's category (sig. 0.019). The opposite results were observed in the women's category (sig. 0.683). Performance comparison groups of men and women were different and statistically highly significant (sig. 0.000). Another result of this work is to establish standards by T - points for members of the youth sports center (YSC) in the triathlon for the assessment test at maximum cadence bicycle ergometer test in Cyclus 2. Keywords: pedaling cadence, YSC, diagnostics, maximum pedaling cadence test, Mann- Whitney test
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ČIHÁKOVÁ, Veronika. "Chování a biomechanika kriticky ohroženého hnědáska chrastavcového \kur{(Euphydryas aurinia)}." Master's thesis, 2006. http://www.nusl.cz/ntk/nusl-45197.
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Vaňková, Jana. "Biomechanika whiplash poranění a jeho vliv na struktury krční páteře." Master's thesis, 2006. http://www.nusl.cz/ntk/nusl-270832.
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Title Biomechanics of whiplash injury and its influence on cervical spine structures Objectives: Objective of the work is charting of studies examining mechanism and course whiplash event, its influence on osseous and arthral textures, intervertebral discus, ligaments, neural textures, cerebro-spinal fluid and vertebral artery. In summary form mention possibilities of prevention in terms ofconstruction car. Method: Diploma work is processed in the form of commented literary background research. Results: Confrontation of individua! works brought definite results, respecting kinematics cervical spine at rear impact. Most ofin vivo and in vitro studies confirmed clear two-phase answer. Immediately after stroke (50 - 110 msec) cervical spine is forming S-form deformation with flection UCS and extension LCS, whereas it is extension with abnormal JAR. Whole spine is loaded by compression at this time. The second period is C-form deformation with extension whole cervical spine. Risk of structures injury is the highest in S- stage. The most often it is localized in LCS, and it is in intervertebral joints including capsular ligaments, intervertebral discus and anterior longitudinale ligament. There are threatened also neural textures, both influence oftension force applied to UCS, and pressurized gradient...
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Velebil, Matěj. "Rozvoj tenisové techniky." Master's thesis, 2021. http://www.nusl.cz/ntk/nusl-446999.
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Title: Development of tennis technique Objectives: The main object of this thesis is to analyse the fundamental factors that affect the development of tennis technique. Furthermore, this thesis presents the most common deviations from the optimal tennis technique, including their possible causes, and consequently suggests possible corrections that would help optimise the technique. Methods: Based on the analysis of documents, are present the fundamental factors that influence tennis technique. Specific selected deviations are develop from the optimal tennis technique on the parts of the basic strokes, in which the specific deviations, its description and the causes are stated. Furthermore, methods of correction to eliminate the mentioned technical deviations are proposed. This methods are based on the analysis of documents and observations from our own past experience. Results: The result is a detailed analysis of factors that affect the development of tennis technique. Furthermore, a list of deviations from the optimal technique with possible causes and proposed methods of their possible correction. The theoretical basis of the work deals with tennis technique as a fundamental factor influencing sports performance in tennis. Keywords: Biomechanics, exercises, correction, deviation, stroke
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Hrachovcová, Monika. "Kinematická analýza bežecké lokomoce dětí ve věku 6-8 let." Master's thesis, 2020. http://www.nusl.cz/ntk/nusl-435680.
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This diploma thesis deals with the biomechanics of running and the kinematic analysis of running in children aged 6 - 8 years. The paper consists of two parts. The first part deals with the biomechanics of running and its development, running injuries and describes the kinematic analysis of running. The PubMed, the ScienceDirect Database and sources of the National Medical Library and of the Charles University were searched for creating this theoretical part. The second part describes the experiment - methods and its results. 70 children were recorded during overground running at spontaneous speed. The obtained video recording was measured using the Kinovea 0.8.12. program. The video was scrolled through frames and three moments of the stance phase (initial contact, midstance and moment toe-off) were detected. At these moments selected angles in the sagittal plane were analyzed. These angles were described in the terms of descriptive statistics. Certain characteristics subdivided the cohort into two groups. These were compared in kinematic parameters to determine statistically significant differences. The obtained values from the experiment are discussed and compared with the the values from the recent literature dealing with kinematics of running. At last the suggestions for further research are...
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Sacherová, Jana. "Axiální systém člověka: možnosti identifikace změn pojivových tkání." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-324846.
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Title: Human axial system: identification of connective tissues changes Objectives: The main objective of this thesis was to compile a review of techniques and methods currently used in identification of connective tissues changes. Methods: The method used in this thesis is a critical literature review - a study of research papers from available information sources accompanied by author's comments. Foreign sources are represented mostly by research papers accessible via electronic archives such as ScienceDirect, Pubmed, Springer, Wiley. Also other foreign publications were used. The theoretical part is focused on basic anatomy and physiology of the spine and states main methods of identification of connective tissues changes involved in this area. The main part describes particulars of researches dedicated to identification of functional and morphological characteristics of different spinal components. Results: In addition to classic methods of spinal research, the thesis introduces also new developing techniques and methods. Procedures used in current research are described; their advantages and limits are explained. Key words: spine, biomechanics, loading, intervertebral disc, method
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Málková, Monika. "Experimentální analýza pohybového projevu osob." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-330042.
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Title: Experimental motion analysis of human locomotion Objectives: The aim of this work is verification of the hypothesis that it is possible to identify humans using measurement of parameters of their gait taken from surveillance camera's records. Methods: In our thesis we used the method of comparison. The aim of the experiment is comparison of parameters measured in different trials of each subject under different conditions (different walking speeds, with or without clothes on, and using either 2D or 3D record), as well as comparison across different subjects. Results: We found that using a 3D record of human gait, it is possible to improve our capability of identifying them. We also found that it is necessary to compare either dressed subjects strictly among themselves or stripped subjects strictly among themselves, because otherwise the comparison is not meaningful. Furthermore, we found that using our geometrical methods, it is possible to deduce gait parameters from a 2D camera record when it comes to height of the subject, but not so for length of their step. Keywords: gait, identification, kinematic analysis, forensic biomechanics
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Gono, Filip. "Návrh databáze evidence selhání stromů." Master's thesis, 2010. http://www.nusl.cz/ntk/nusl-426117.
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Musil, Daniel. "Výskyt prvků reflexní lokomoce při přeběhu překážky." Master's thesis, 2015. http://www.nusl.cz/ntk/nusl-348608.
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Title: The Appearance of the reflex locomotion elements in the hurdle clearance stride Thesis Objective: The main objective of this thesis is to state the frequency of the presence of reciprocal inhibition (RI) and cross extensor reflex (CI - contralateral inhibition) during hurdle overrun. Methods: The subjects were tested during running over three hurdles with modified distances similar to the 110m hurdles. The height of the hurdles was set to 0,99 m. The muscle activity was monitored by surface electromyography and video was recorded simultaneously. The hurdle clearance was divided into particular phases which altogether formed one cycle. Collected data was analyzed by the software Megawin (rectification, smoothing, and synchronization with camera) and subsequently converted into software MATLAB. Nine cycles of each subject were averaged. Such modified cycle was evaluated consequently. Results: Reflex locomotion (RI and CI) was presented more often in the group with less experience with the hurdles. Co-activation of antagonist muscles was typical for the group consisting of more experienced individuals, rather than RI and CI. Key Words: hurdles, biomechanics, sEMG, reciprocal inhibition, contralateral inhibition
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Hrušková, Natália. "Experimentální vyšetření parametrů chůze člověka." Master's thesis, 2014. http://www.nusl.cz/ntk/nusl-341498.
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Title: Experimental investigation of human gait analysis parameters Objective: The main objective of diploma thesis was an experiment, that examined kinematic and dimensional parameters of human gait which was captured by several cameras and acquired data was recorded in 2D and 3D measurement. Secondary objective was to compare and statistically evaluate data acquired from measurement. The objective of analysis was to discover and describe possible regularities, patterns of human gait and other connections in investigated subjects. Methods: Comparative method was used in the thesis. The purpose of the experiment was to compare parameters measured during attempts of every subject that were conducted under different conditions (different velocity, dressed, undressed, in the environment of 2D and 3D recording) and also to compare different subjects with each other. Results: In the experiment we observed that it is possible to prove the relation between the length of a step and the velocity of gait and also the relation between the change in the body height and the velocity of human gait by three dimensional recording of gait and its analysis. This contention was confirmed in the comparison dressed and undressed subjects. The result of the experiment was, that with increasing velocity of gait is...
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Maleček, Jan. "Vztah mezi svaly kyčelního kloubu a dynamikou přímého kopu při použití balistické vesty a batohu." Master's thesis, 2018. http://www.nusl.cz/ntk/nusl-388025.
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Title: Relationship between hip muscles and dynamics front kick while using ballistic vest and backpack. Objective: Determine the rate of the relationship among isokinetic strength of hip muscles during flexion and extension movement, external and internal rotation and the dynamics of the front kick while using the military personal protective equipment. The method: The master thesis corresponds with an empirically based study of observational type. The measured research sample consisted of students (n = 15) of Military Department attending full-time and combined form of study at the Faculty of Physical Education and Sport of Charles University in Prague. Dynamics of front kick were measured by dynamometric Kistler plates and evaluated through computer software BioWare. Isokinetic strength of hip muscles during flexion and extension movement, external and internal rotation was tested and rated by isokinetic dynamometer Humac Norm. The flexibility of selected muscles group was measured by a specialist in physiotherapist area. The Spearman rank correlation coefficient of the order (rs) was chosen for the final evaluation of the rate of relationship. The results: The strongest correlation relationship was between the external hip rotation muscles (at speed 90 řs-1 ) and the impact force on the...
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Čajka, Vladimír. "Srovnání posturální stabilizace u atletů a trailových běžců pomocí posturální somatooscilografie." Master's thesis, 2015. http://www.nusl.cz/ntk/nusl-348570.
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Title: Comparison of postural stabilization of athletes and trail runners with postural somatoosilography. Objectives: The main aim of this study is comparison of postural stability of athletes (track runners) and trail runners. We want to determine, if run in the field can affect positive postural stabilization. Methods: In our thesis we used a method of analysis and a method of comparison. Analysis is performed with postural somatooscilography (PSOG). This method contains postural provocation test on Posturomed. Oscilation of this platform is shooted in program Microswing 5.0. Then these dates are evaluated in program Posturomed Commander. We compared these dates with statistical methods and box plots in program Statistica 10 and Microsoft Excel 2007. Results: We found out when we compared 17 trail runners and 11 track runners that trail runners reached better postural stability. Trail runners had better postural stability in the first measurement and also had better results in comparison of three measurements. Track runners achieved the best results in the third measurement and trail runners had the best results of postural stabilization in the second measurement. Keywords: postural stabilization, biomechanics of running, Posturomed, postural somatooscilography