This thesis deals with stress analysis strain proximal end of tibia with total joint replacements. The analysis is done on the basis of deformation characteristics of voltage, through the finite element method (FEM). We have developed two-dimensional models of the proximal end of tibia with tibial components total endoprosthesis (TEP), without loss and bone loss. Geometry model is created based on data obtained from computerized tomography, which were further processed in the program, Rhinoceros 3.0 and SolidWorks 2009th Computational solution was carried out by finite element method in Ansys Workbench 12.0. The model without loss of bone tissue was tested the hypothesis that the deformation is very small and there is no violation of the shank prosthesis. Due to loss of bone tissue is lost support to the tibial pulse in the proximal tibia and by a progressive increase in stress, which can lead to a breach of the shank total joint replacement. The analysis results show that, if the loss of bone tissue, so that the tibial part of the TEP will lose support, there is a crack stem total hip replacement due to stress.

The presented Master’s Thesis aims at determining stress and strain distribution in proximal femur with applied PCCP and DHS systems. The DHS system has been widely and successfully used for treating intertrochanteric fractures of proximal femur; in some cases, however, complications concerning implant cut-out and excessive fracture collapse occur. To minimize the risk of stabilization failure, the PCCP system was designed. In the Thesis, the process of creating the numerical model is described and the results obtained by employing Finite Element Method are presented. The 3D models of implants’ geometry were created based on the real objects. The model of proximal femur geometry was built by utilizing a series of CT scans and divided into two bodies with respect to the AO classification afterwards. The loading was obtained by solving the static equilibrium equations for the loose lower extremity. The computation was run in Ansys Workbench v13 software. In the hip screws of the PCCP system, lower values of equivalent stress can be found when compared to the DHS system. However, the equivalent strain generated in the proximal fragment is 3-times higher when the PCCP system is employed than in case of DHS system which may be due to the self-cutting design of PCCP screws. By employing PCCP system, the risk of implant failure is decreased. On the other hand, the bone tissue of the proximal fragment in close vicinity of the implant screws seems to be overloaded and prone to collapse.

This thesis deals with audio inpainting problem. Firstly, basic concepts are summarized. Then, sparse representation of signals is introduced along with several algorithms. In the main part dedicated to the audio inpainting, the problem is defined and actual methods are presented and compared. The newest approach using the harmonic strucure of sound signals is then introduced, followed by several experiments and evaluation. Lastly, an algorithm ensuring the maximal computational efficiency is derived.

The JPEG codec is currently the most widely used image format. This work deals with the design and implementation of an alternative JPEG codec using proximal algorithms in combination with the fixation of points from the original image to suppression of artifacts created in common JPEG coding. To solve the problem, the prox_TV and then the Douglas-Rachford algorithm were used, for which special functions using l_1-norm for image reconstruction were derived. The results of the proposed solution are very good because they can effectively suppress the artefacts created and the result corresponds to the image with a higher set qualitative factor. The proposed method achieves very good results for both simple images and photos, but in the case of large images (1024 × 1024 px) and larger, a large amount of computing time is required, so the method is more suitable for smaller images.

Depuis quelques années les détecteurs à pixels hybrides ont ouvert la voie au développement de la tomographie à rayon X spectrale ou tomodensitométrie (TDM) spectrale. La TDM spectrale permet d’extraire plus d’information concernant la structure interne de l’objet par rapport à la TDM d’absorption classique. Un de ses objectifs dans l’imagerie médicale est d’identifier et quantifier des composants d’intérêt dans un objet, tels que des marqueurs biologique appelés agents de contraste (iode, baryum, etc.). La majeure partie de l’état de l’art procède en deux étapes : - la "pré-reconstruction" qui consiste à séparer les composants dans l’espace des projections puis reconstruire, - la "post-reconstruction", qui reconstruit l’objet puis sépare les composants.On s’intéresse dans ce travail de thèse à une approche qui consiste à séparer et reconstruire simultanément les composants de l’objet. L’état de l’art des méthodes de reconstruction et séparation simultanées de données de TDM spectrale reste à ce jour peu fourni et les approches de reconstruction existantes sont limitées dans leurs performances et ne tiennent souvent pas compte de la complexité du modèle d’acquisition.L’objectif principal de ce travail de thèse est de proposer des approches de reconstruction et séparation tenant compte de la complexité du modèle afin d’améliorer la qualité des images reconstruites. Le problème à résoudre est un problème inverse, mal-posé, non-convexe et de très grande dimension. Pour le résoudre, nous proposons un algorithme proximal à métrique variable. Des résultats prometteurs sont obtenus sur des données réelles et montrent des avantages en terme de qualité de reconstruction. / In recent years, hybrid pixel detectors have paved the way for the development of spectral X ray tomography or spectral tomography (CT). Spectral CT provides more information about the internal structure of the object compared to conventional absorption CT. One of its objectives in medical imaging is to obtain images of components of interest in an object, such as biological markers called contrast agents (iodine, barium, etc.).The state of the art of simultaneous reconstruction and separation of spectral CT data methods remains to this day limited. Existing reconstruction approaches are limited in their performance and often do not take into account the complexity of the acquisition model.The main objective of this thesis work is to propose better quality reconstruction approaches that take into account the complexity of the model in order to improve the quality of the reconstructed images. Our contribution considers the non-linear polychromatic model of the X-ray beam and combines it with an earlier model on the components of the object to be reconstructed. The problem thus obtained is an inverse, non-convex and misplaced problem of very large dimensions.To solve it, we propose a proximal algorithmwith variable metrics. Promising results are shown on real data. They show that the proposed approach allows good separation and reconstruction despite the presence of noise (Gaussian or Poisson). Compared to existing approaches, the proposed approach has advantages over the speed of convergence.

Background: To ensure adequate function after orthopedic tumor reconstruction, it is important to reattach the remaining soft tissue to the implant. This study aimed at obtaining mechanical properties of textile muscle-implant and muscle-bone connections in a preliminary test. Methods: Two groups of soft-tissue attachment were mechanically tested and compared: Native bone-muscle samples obtained from human femora and muscles attached to a prosthetic implant by means of Trevira® attachment tubes. Additionally, muscle samples were tested with muscle fibers aligned parallel and perpendicular to the tension load. A uniaxial load was exerted upon all samples. Results: Failure loads of 26.7 ± 8.8 N were observed for the native bone-muscle group and of 18.1 ± 9.9 N for the Trevira® group. Elongations of 94.8 ± 36.2 % were observed for the native bone-muscle group and 79.3 ± 51.8 % for the Trevira® group. The location of failure was mainly observed in the central area of the muscle fibers. Muscle fibers with parallel fiber orientation (47.6 ± 11.5 N) yielded higher tensile strength than those with perpendicular fiber orientation (14.8 ± 4.1 N). Conclusions: Our experiments showed that higher forces were transmitted in the origin and insertion areas than in areas of flat soft tissue reconstruction using attachment tubes. The data indicate that the tested material allows reattaching muscles, but without reinforcing the insertion site. Therefore, attachment tubes with region-dependent and potentially anisotropic material behavior might be advantageous to optimize muscle-bone load transmission after surgery, which may allow lower complication rates and shorter physical recovery.

Background: Complex proximal humerus fractures with metaphyseal comminution remain challenging regarding reduction and stability. In most fracture patterns the hard bone of the bicipital groove remains intact. In this case series, we describe a novel technique of hybrid double plate osteosynthesis of complex proximal humerus fractures with metaphyseal comminution. Methods: In randomly chosen shoulder specimens and synthetic bones, pilot studies for evaluation of the feasibility of the technique were performed. Between 4/2010 and 1/2012 10 patients underwent hybrid double plate osteosynthesis. Seven patients (4 male, 3 female, mean age was 50 years (range 27–73)) were available for retrospective analysis. Based on plain radiographs (anterior-posterior and axial view), the fractures were classified according to the Orthopaedic Trauma Association classification (OTA) and by descriptive means (head-split variant (HS), diaphyseal extension or comminution (DE)). Results: Follow-up radiographs demonstrated complete fracture healing in six patients and one incomplete avascular necrosis. None of the patients sustained loss of reduction. Three patients where reoperated. The medium, not adapted, Constant score was 80 Points (58–94). Patients subjective satisfaction was graded mean 3 (range: 0–6) in the visual analog scoring system (VAS). Conclusion: The technique of hybrid double plate osteosynthesis using the bicipital groove as anatomic landmark may re-establish shoulder function after complex proximal humerus fractures in two dimensions. Firstly the anatomy is restored due to a proper reduction based on intraoperative landmarks. Secondly additional support by the second plate may provide a higher stability in complex fractures with metaphyseal comminution.

Im Rahmen einer Kaufuntersuchung beim Pferd ist es von besonderem Interesse leistungsmindernde Faktoren aufzudecken. Dem Tierarzt stehen zu diesem Zwecke sowohl standardisierte Protokolle für die Durchführung der klinischen Untersuchung als auch der „Leitfaden für die röntgenologische Beurteilung bei der Kaufuntersuchung“ (Röntgenleitfaden 2007)zur Verfügung. Bezüglich der Anzahl der im Rahmen einer Kaufuntersuchung angefertigten Röntgenaufnahmen gibt es fortwährende Diskussionen. Besonders deutlich wird diese Problematik im internationalen Vergleich. Jedes Land, zum Teil auch die verschiedenen Zuchtverbände, verlangen unterschiedliche Standardaufnahmen. Ziel der Arbeit war die Überprüfung der Darstellbarkeit röntgenologischer Befunde im Bereich des Fesselgelenks, der Gleichbeine und des Fesselbeins, durch die im Röntgenleitfaden 2007 angegebene Standardaufnahme „Zehe 90°“ und die daraus resultierende Einteilung in Röntgenklassen. Es sollte geprüft werden wie sich die Einteilung der Röntgenklasse nach einer computertomographischen Darstellung und Befundung ändert. Von besonderem Interesse waren zusätzlich solche Befunde, die röntgenologisch nicht darstellbar waren, aber in der CT-Untersuchung gefunden werden konnten. Zur Untersuchung wurden 200 distale Gliedmaßen von 51 niedersächsischen Schlachtpferden röntgenologisch, computertomographisch und makroskopisch im Frisch- und Knochenpräparat herangezogen. Die Pferde wurden anhand der röntgenologischen Übersichtsaufnahme „Zehe 90°“ nach dem Schema des Röntgenleitfadens 2007 in Klassen eingeteilt. Anschließend erfolgte eine computertomographische Untersuchung. Ausgewertet wurden diese Bilder an einer Workstation, welche die Möglichkeit verschiedenster Rekonstruktionen bietet. Nachfolgend wurden die Pferde aufgrund der in der CT gefundenen Veränderungen in ihren Röntgenklassen korrigiert. Befunde, die nicht im Röntgenleitfaden aufgeführt sind, wurden gesondert betrachtet und im Rahmen einer Modellrechnung ausgewertet. Diese Modellrechnung betrachtet computertomographische Befunde, deren Detektion auch in einer röntgenologischen 0°Aufnahme der distalen Gliedmaße theoretisch zu erwarten gewesen wären. Diese Befunde wurden dann in die Klassifizierung der einzelnen Pferde einbezogen, um den Nutzen einer solchen zusätzlich zu der Standardaufnahme (Zehe 90°) angefertigten Röntgenaufnahme zu beurteilen. Im Anschluss wurden alle röntgenologischen und computertomographischen Befunde im Frisch bzw. Knochenpräparat aufgesucht und photographisch festgehalten. Fokus aller Untersuchungen war stets die Fesselgelenkregion sowie das distale Fesselbein. Die Einteilung der Pferde in eine bestimmte Röntgenklasse anhand ihrer Befunde im Fesselgelenkbereich änderte sich bei 84,31 % (n=51) der Pferde nicht, oder nur bis zu einer halben Röntgenklasse. Die meisten Pferde (43,14 %, n=51) der untersuchten Population ließen sich aufgrund ihrer Befunde im Fesselgelenk in Anlehnung an den Röntgenleitfaden 2007 in die Zwischenklasse II-III einordnen. Auch im Bereich der gesamten distalen Gliedmaße war es möglich 82,36 % (n=51), der Pferde röntgenologisch in eine Röntgenklasse einzuteilen, so dass sich auch nach der computertomographischen Untersuchung keine Veränderung, oder nur eine Änderung um eine halbe Klasse ergaben. Die als Goldstandard verwendete Computertomographie, erlaubte in dieser Arbeit die Annahme einer hypothetisch angefertigten 0° Aufnahme der Fesselgelenkregion. Diese Aufnahme ermöglicht vor allem die Detektion zystoider Defekte im Bereich der distalen Gliedmaße und führt zu einer Erhöhung der Anzahl der Pferde, die sich nicht in ihrer Röntgenklasse verändern, von 66,70 % auf 78,43 %.

This thesis is concerned with the removal of artefacts typical for JPEG im- age compression. First, we describe the mathematical formulation of the JPEG format and the problem of artefact removal. We then formulate the problem as an optimization problem, where the minimized functional is obtained via Bayes' theorem and complex wavelets. We describe proximal operators and algorithms and apply them to the minimization of the given functional. The final algorithm is implemented in MATLAB and tested on several test problems. 1

Divorce is a potentially destructive reality in society. According to the bio-ecological model of Bronfenbrenner, the development of the child takes place within two micro family systems when a family is reconstituted following divorce: the primary micro family system, where the child resides permanently with his/her biological parent who has parental rights and responsibilities, as well as the secondary micro family system of the other biological parent who also has parental rights and responsibilities, where the child visits periodically. Challenges that the child faces in the context of the reconstituted family thus include shared membership of the two micro family systems and the complexity of the mesosystem. Resilience can be defined as a process of the inborn ability to achieve positive outcomes and to adjust successfully despite challenges and adverse living conditions. The purpose of the study was twofold: firstly, to achieve understanding of the way in which middle-adolescents of divorced parents, in moving between the two micro family systems of their reconstituted families, utilise their resilience to develop optimally in spite of a probably dysfunctional relationship between their biological parents at the mesosystemic level and secondly, to contribute to the fields of knowledge on resilience and bio-ecological theory in order to enhance educational psychology praxis with regard to the adaptation of adolescents of divorced parents in reconstituted families. The study was qualitative, and conducted in the interpretive paradigm. A multiple case study with a purposeful sampling of four participants was used. Unstructured narrative conversations were conducted, which included a resilience-based therapeutic intervention to facilitate sensitisation regarding personal strengths and assets in accordance with the assetbased approach. The format of the data description and analysis was defined by the narrative way of working. The participants’ utilisation of resilience qualities was evaluated in accordance with a definition of resilience which had been newly constructed by means of a synthesis of the bio-ecological model, positive psychology and the focuses of the first three waves of resilience research. The findings of the study indicated that the way in which middle-adolescents utilise their resilience depends on a therapeutic process (a personal, controlled process) as well as the nature of the mesosystem in their developmental context (a factor that can only be controlled by the divorced biological parents). In respect of a therapeutic process, the utilisation of the middle-adolescents’ resilience depends on their emotional security to make conscious choices to mobilise their resilience and consequently change their behaviour in order to cope effectively with difficult family circumstances in both their micro-family systems. In respect of the nature of the mesosystem, the utilisation of the middle-adolescents’ resilience depends on the effectiveness of the relationship between their divorced biological parents at the mesosystemic level. The utilisation of resilience per se is apparently dependent on some consistent systemic foundation in the developmental context of the child, which is, in the case of divorce, the mesosystem. / Thesis (PhD)--University of Pretoria, 2011. / Educational Psychology / unrestricted