On January 29-30, 2008 a squall line of thunderstorms moved through the Ohio Valley resulting in four deaths and one injury. Such events highlight the importance of accurate forecasting for public safety. Mesoscale Modeling plays an important role in any forecast of a potential squall line. The focus of this study was to examine the performance of several parameterization scheme combinations in the Weather Research and Forecasting Model version three (WRF) as they related to this event. These examinations included cloud microphysics (WRF Single-Moment 3-class, 6-class, and Goddard), cumulus parameterization (Kain-Fritsch and Bets-Miller-Janjic) and planetary boundary layer schemes (Yonsei-University and Mellor-Yamada-Janjic). A total of 12 WRF simulations were conducted for all potential scheme combinations. Data from the WRF simulations for several locations in south central Kentucky were analyzed and compared using Kentucky Mesonet observations for four locations: Bowling Green, Russellville, Murray and Liberty, KY. A fine model resolution of 1 km was used over these locations. Coarser resolutions of 3 km and 9 km were used on the outer two domains, which encompassed the Ohio and Tennessee Valleys. The model simulation performance was assessed using established statistical measures for the above four locations and by visually comparing the North American Regional Reanalysis dataset (NARR) along with modeled simulations. The most satisfactory scheme combination was the WRF Single-Moment 3-class Microphysics scheme, Kain-Fritsch cumulus parameterization scheme and Yonsei University scheme for the planetary boundary layer. The planetary boundary layer schemes were noted to have the greatest influence in determining the most satisfactory model simulations. There was limited influence from different selections of microphysics and cumulus parameterization schemes. The preferred physics parameters from these simulations were then used in six additional simulations to analyze the affect different initialization data sets have with regards to model output. Data sets used in these simulations were the Final Operational Analysis global data, North American Regional Reanalysis (3 and 6 hour) and the North American Mesoscale Model at 1, 3 and 6 hour timesteps, for a total of six simulations. More timesteps or an increase in model resolution did not materially improve the model performance.

Spatio-temporal control of the self-ordered structures by use of the time-dependent oscillatory fields of zero-time average, either deterministic (temporally regular) or noisy (temporally irregular) ones, has today become a fundamental field of multidisciplinary research in a wide variety of the highly nonlinear systems of the different physical origin. The self-ordered bistable fronts in the essentially dissipative systems of the reaction-diffusion type, that are formulated by parabolic partial differential equations, are investigated in the dissertation. The objective of the research is to investigate new possibilities of controlling the directed net motion of the self-ordered bistable fronts by the deterministic and stochastic zero-mean ac forces using computer modeling and analytic tools. In order to achieve the objective mathematical and numerical models were applied, computer software was created and new possibilities of controlling the directed net motion of bistable fronts by use of the zero-average periodic, quasi-periodic and bounded noise fields were investigated. / Savaime susidarančių lokalizuotų struktūrų valdymas deterministiškai (reguliariai) arba stochastiškai (atsitiktinai) osciliuojančiais laukais, kurių vidutinė vertė yra nulis, yra plačiai paplitęs įvairiose terpėse. Disertacijoje nagrinėjami savame susidarantys bistabilūs frontai disipatyviose sistemose, kurios aprašomos netiesinėmis parabolinėmis diferencialinėmis lygtimis su dalinėmis išvestinėmis. Disertacijos tikslas yra ištirti kryptingo bistabilių frontų dreifo valdymo nuliniais laukais galimybes, taikant kompiuterinį modeliavimą bei analitinius metodu. Tikslui pasiekti buvo sudaryti matematinis bei skaitinis modeliai, sukurta programinė įranga ir skaitiškai ištirtos savaiminių bistabilių frontų valdymo galimybės, naudojant periodinius, kvaziperiodinius ir stochastinius nulinius laukus.

Savaime susidarančių lokalizuotų struktūrų valdymas deterministiškai (reguliariai) arba stochastiškai (atsitiktinai) osciliuojančiais laukais, kurių vidutinė vertė yra nulis, yra plačiai paplitęs įvairiose terpėse. Disertacijoje nagrinėjami savame susidarantys bistabilūs frontai disipatyviose sistemose, kurios aprašomos netiesinėmis parabolinėmis diferencialinėmis lygtimis su dalinėmis išvestinėmis. Disertacijos tikslas yra ištirti kryptingo bistabilių frontų dreifo valdymo nuliniais laukais galimybes, taikant kompiuterinį modeliavimą bei analitinius metodu. Tikslui pasiekti buvo sudaryti matematinis bei skaitinis modeliai, sukurta programinė įranga ir skaitiškai ištirtos savaiminių bistabilių frontų valdymo galimybės, naudojant periodinius, kvaziperiodinius ir stochastinius nulinius laukus. / Spatio-temporal control of the self-ordered structures by use of the time-dependent oscillatory fields of zero-time average, either deterministic (temporally regular) or noisy (temporally irregular) ones, has today become a fundamental field of multidisciplinary research in a wide variety of the highly nonlinear systems of the different physical origin. The self-ordered bistable fronts in the essentially dissipative systems of the reaction-diffusion type, that are formulated by parabolic partial differential equations, are investigated in the dissertation. The objective of the research is to investigate new possibilities of controlling the directed net motion of the self-ordered bistable fronts by the deterministic and stochastic zero-mean ac forces using computer modeling and analytic tools. In order to achieve the objective mathematical and numerical models were applied, computer software was created and new possibilities of controlling the directed net motion of bistable fronts by use of the zero-average periodic, quasi-periodic and bounded noise fields were investigated.

The objective of this study was to: (1) model the course of the lingual nerve (LN) in the third molar region using digitized data and (2) investigate landmarks to aid in predicting the position of LN. A MicroScribe 3-DX digitizer and Autodesk® Maya® 8.5 were used to create 3-D in-situ models of LN for seven human cadaveric specimens. Regression analysis demonstrated that an anteriorly positioned lingula is directly proportional to the vertical distance of the LN relative to the alveolar crest (p < 0.05). A superiorly positioned mylohyoid ridge was also directly proportional to the vertical distance of the LN relative to the alveolar crest (p < 0.05). The LN is positioned closer to the alveolar crest in specimens where the mylohyoid ridge is positioned superiorly (p = 0.001). This study demonstrated a novel way of quantifying the relative position of the LN using 3-D computer modeling.

The objective of this study was to: (1) model the course of the lingual nerve (LN) in the third molar region using digitized data and (2) investigate landmarks to aid in predicting the position of LN. A MicroScribe 3-DX digitizer and Autodesk® Maya® 8.5 were used to create 3-D in-situ models of LN for seven human cadaveric specimens. Regression analysis demonstrated that an anteriorly positioned lingula is directly proportional to the vertical distance of the LN relative to the alveolar crest (p < 0.05). A superiorly positioned mylohyoid ridge was also directly proportional to the vertical distance of the LN relative to the alveolar crest (p < 0.05). The LN is positioned closer to the alveolar crest in specimens where the mylohyoid ridge is positioned superiorly (p = 0.001). This study demonstrated a novel way of quantifying the relative position of the LN using 3-D computer modeling.

L’objectif général de ma thèse est de développer une modélisation spatialisée à l’échelle d’un versant, afin de mieux rendre compte des principales voies de transfert des pesticides dans les terrains agricoles. Je cherche à adopter une approche simplifiée, mais qui permet néanmoins de représenter les discontinuités existantes (parcelles, fossés, talus … etc). En effet, on souhaite pouvoir quantifier les mécanismes du transfert des pesticides en prenant en compte l’influence des éléments du paysage (parcelles, fossés, bandes enherbées …etc) sur la partition des transferts d’eau et de pesticides en surface et en subsurface. On s’appuie pour ce développement sur les données acquises sur le bassin versant expérimental de la Morcille (69), qui servent à fournir des ordres de grandeur et un cadre pour tester la pertinence des développements effectués. Une synthèse bibliographique sur les processus en jeu et les modèles existants a conduit au choix de la plateforme de modélisation hydrologique CMF, développée à l’université de Giessen (Kraft, 2012). Cette dernière permet une modélisation orientée objet d’un système hydrologique (colonne de sol, versant, bassin versant ...etc) et propose une grande variété d’équations physiques pour la représentation des processus hydrologiques. Le travail est mené sur trois étapes, une première consiste à l’évaluation du comportement de la plateforme et la validation de sa réponse via la comparaison dans un premier temps via un modèle 1D suite à une comparaison avec Hydrus1D. Dans un second temps, nous avons mené des simulations en 2D en comparant avec le modèle Cathy en se basant sur les travaux de Sulis et al. (2010) et avec Hydrus2D (Simunek et al., 1999 & Simunek et al., 2001) sur un versant inspiré du versant expérimental de la Morcille. La deuxième étape consiste à la prise en compte des écoulements préférentiels dans certains types de sol structurés, nous paraît nécessaire pour une meilleure représentation des processus en jeu. La représentation du transfert préférentiel des produits phytosanitaires via les macropores vers la ressource en eau représente encore un défi pour la recherche. L’approche à double perméabilité (DP) choisie contient le développant d’une nouvelle fonction d’infiltration dans les macropores. Notre modèle DP contient également deux fonctions alternatives d’échange matrice-macropores ; la première est proportionnelle à la différence des teneurs en eau des deux compartiments du sol (Philip, 1968). La deuxième fonction d’échange est une onde diffusante basée sur l’approche présentée par van Genuchten (1993). La dernière partie de la thèse consiste en la modélisation des solutés suivant successivement les deux approches : simple porosité et double perméabilité, en considérant le transport des solutés par convection et une adsorption linéaire. La validation de notre approche de modélisation est menée en comparant avec les simulations d’Hydrus1D/2D. / The aim of my thesis is to develop a spatial scale modeling of a catchment, to better reflect the main pathways of pesticides in agricultural lands. We are looking to adopt a simplified approach, yet it allows to represent the existing discontinuities (plots, ditches, embankments ... etc). Indeed, we wish to quantify the mechanisms of transfer of pesticides taking into account the influence of landscape features (patches, ditches, grass strips ... etc) on the partition of water transfers and pesticides in surface and subsurface. It relies for this development on the acquired data on the experimental watershed Morcille (69), which serve to provide orders of magnitude and a framework to test the relevance of business developments. A literature review on the processes involved and the existing models led to the choice of hydrological modeling framework CMF, developed at the University of Giessen (Kraft, 2012). CMF allows for object oriented modeling of a hydrologic system (soil column, slope, watershed etc.) and offers a wide variety of physical equations for the representation of hydrological processes. The work is conducted in three steps, the first involves assessing the behavior of CMF and validating its response via the comparison initially via a 1D model following a comparison with Hydrus1D. Secondly, we conducted 2D simulations comparing with the Cathy model based on the work of Sulis et al. (2010) and Hydrus2D (Simunek et al., 1999 & Simunek et al., 2001) on a hillslope inspired from the experimental slope of Morcille. The second step is to take account of preferential flow in certain types of structured soil, seems necessary for better representation of the processes. The representation of the preferential transfer of pesticides through macropores to water resources is still a research challenge. The dual permeability approach (DP) contains selected developing the infiltration of a new function in the macropores. Our DP model also contains two alternative exchange functions matrix-macropores; the first one is proportional to the difference of the water contents of the two compartments of the soil (Philip, 1968). The second exchange function is a diffusing wave based on the approach outlined by van Genuchten (1993). The last part of the thesis consists in the modeling of solutes successively following two approaches: single dual porosity and permeability, considering the convective transport of solutes and a linear adsorption. The validation of our modeling approach is conducted by comparing with the Hydrus1D / 2D simulations.

Para melhorar a visualização das pequenas estruturas anatômicas importantes para o diagnóstico do câncer de mama e otimizar o processamento das mamografias pelos sistemas computadorizados de auxílio ao diagnóstico (CAD), foi desenvolvido um dispositivo, baseado na tecnologia slit, que melhora a aquisição dos mamogramas. Este dispositivo reduz a radiação espalhada e o tamanho do foco e foi projetado a partir de um modelo computacional. O modelo adotado permite quantificar o valor desses parâmetros para qualquer sistema radiológico, qualquer espessura de tecidos moles radiografada e qualquer tensão aplicada ao tubo de raios-X. O dispositivo foi implementado e testado, quantificando as melhorias obtidas. As imagens geradas foram comparadas com as fornecidas pelos sistemas mamográficos convencionais. O modelo serviu para estudar também a interferência do espalhamento sobre o desempenho dos algoritmos usados nos sistemas de diagnóstico auxiliado por computador (CAD). / In order to improve the visualization of the small and important anatomical structures for breast cancer diagnosis and to optimize the image processing of mammograms by the computer aided diagnosis systems (CAD), a device that comes from slit technology was developed to improve the acquisition of mammograms. This device reduces the amount of scattered radiation and the focus size and it can be projected from a computational model. This model allows quantifying the value of those parameters, scattered radiation and the focus size, for any radiological system, any X-rayed soft tissue thickness and any tension applied to the X-ray tube. The device was implemented and tested quantifying the obtained improvements. The generated images were compared to the supplied for conventional mammography systems. The model was also good for studying interference on the algorithms used in the computer aided diagnosis systems (CAD).

Orientador: Jose Raimundo de Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-04T08:07:39Z (GMT). No. of bitstreams: 1 AlvarezMamani_AnaBeatriz_M.pdf: 3814133 bytes, checksum: 31badc94a32b076eeceae360c121c7d5 (MD5) Previous issue date: 2004 / Resumo: Este trabalho aborda a aplicação de diversos esquemas que usam redes neurais para identificação de sistemas e controle de velocidade, objetivando tornar o controle do sistema mais robusto às variações paramétricas, aos distúrbios de medida, e principalmente compensar os efeitos não lineares do ganho dependente da faixa de operação inerentes aos sistemas de velocidade. Para os testes e simulações foi utilizado um automodelo com motor CC. Diferentes bibliotecas do Matlab/Simulink foram utilizadas nas estações de controle para auxiliar nas atividades de simulação. Os resultados mostram um bom desempenho das RNAs na identificação de elementos não lineares, e garantem uma significativa redução do erro do valor predito da velocidade de saída. Os resultados obtidos com o controlador neural por linearização feedback foram aceitáveis e suficientes para o nosso objetivo / Abstract: This work studies the application of projects that use neural networks for identification systems and control of speed, to make the system control more robust to the parametric and measure variations, and mainly to compensate the non-linear effect of the gain related to the inherent range of operation to the speed systems. For simulation and test an automodel with a DC motor was used. Several libraries of the Matlab/Simulink were used in the control stations to assist the activities of simulation. The results show an excellent performance of the RNA¿s in the identification of non-linear elements, and promise a significant reduction of the error of the predicted value of the speed. The results gotten with the neural controller for linearization feedback were acceptable and enough for our objective / Mestrado / Engenharia de Computação / Mestre em Engenharia Elétrica

Plasma membrane transport proteins play a crucial role in all cells by conferring to the cell surface a selective permeability to a wide range of ions and small molecules. The activity of these transporters is often regulated by controlling their amount at the plasma membrane, via intracellular trafficking. The recent boom in the numbers of crystallized transporters shows that many of them that belong to different functional families with little sequence similarity adopt the same structural fold implying a conserved transport mechanism. These proteins belong to the APC (Amino acid-Polyamine-organoCation) superfamily and their fold is typified by the bacterial leucine transporter LeuT. This LeuT fold is characterized by inverted structural repeats of 5 transmembrane domains that harbor the central substrate-binding site and a pseudo-symmetry axis parallel to the membrane. The yeast Saccharomyces cerevisiae possesses about 16 amino acid permeases (yAAPs) that belong to the APC superfamily and that display various substrate specificity ranges and affinities. Topological, mutational analysis and in silico data indicate that yAAPS adopt the LeuT fold.<p><p>In this work we combined computational modeling and yeast genetics to study substrate binding by yAAPs and the endocytosis of these transporters in response to substrate transport. In the first part of this work, we analyzed the selective recognition of arginine by the yeast specific arginine permease, Can1. We constructed three-dimensional models of Can1 using as a template the recently resolved structure of AdiC, the bacterial arginine:agmatine antiporter, which is also a member of the APC superfamily. By comparison of the binding pockets of Can1 and Lyp1, the yeast specific lysine permease, we identified key residues that are involved in the recognition of the main and side chains of arginine. We first showed that the network of interactions of arginine in Can1 is similar to that of AdiC, and that the selective recognition of arginine is mediated by two residues: Asn 176 and Thr 456. Substituting these residues by their corresponding residues in Lyp1 converted Can1 into a specific lysine permease. In the second part of this work, we studied the regulation of two permeases, Can1 and the yeast general amino acid permease, Gap1. In the presence of their substrates, Gap1 and Can1 undergo ubiquitin-dependent endocytosis and targeting to the vacuolar lumen for degradation. We showed that this downregulation is not due to intracellular accumulation of the transported amino acids but to transport catalysis itself. By permease structural modeling, mutagenesis, and kinetic parameter analysis, we showed that Gap1 and Can1 need to switch to an intermediary conformational state and persist a minimal time in this state after binding the substrate to trigger their endocytosis. This down-regulation depends on the Rsp5 ubiquitin ligase and involves the recruitment of arrestin-like adaptors, resulting in the ubiquitylation and endocytosis of the permease.<p><p>Our work shows the importance of the structural analysis of yAAPs to get further insight into the different aspects of their function and regulation. We validate the use of a bacterial APC transporter, AdiC, to construct three-dimensional models of yAAPs that can be used to guide experimental analyses and to provide a molecular framework for data interpretation. Our results contribute to a better understating of the recognition mode of amino acids by their permeases, and the regulation of this transport in response to substrate binding. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

<p>U prvom poglavlju je ukazano na potrebu ugradnje implantata u cilju ponovnog<br />uspostavljanja normalnog funkcionisanja lokomotornog sistema čoveka. Na osnovu<br />analize broja i strukture ugrađenih endoproteza zgloba kuka za 2014. i 2015. godinu na<br />IOHB &bdquo;Banjica&ldquo;, Beograd, i Kliničkom centru Vojvodine Novi Sad, Klinika za ortopediju<br />i traumatologiju, zaključuje se da ovi pokazatelji ukazuju na sličnost i uporedivost, sa<br />podacima iz SAD, u odnosu na broj stanovnika.<br />Drugo poglavlje, u uvodnom delu, sadrži sistematizaciju endoproteza zgloba kuka u skladu sa standardom ISO 7216. Nakon toga, dat je prikaz dosadašnjih rezultata primene tumorskih modularnih endoproteza. Pažnja je poklonjena opisu i varijantnosti konstrukcionih elemenata modularnih endoproteza zgloba kuka, kao i analizi izvedenih konstrukcionih rešenja. Prikaz dosadašnjih istraživanja je upotpunjen analizom patentnih rešenja modularnih endoproteza zgloba kuka. Na kraju, polazeći od prethodno sumiranih saznanja, i iskustva u razvoju protetičkih pomagala je definisan cilj istraživanja, osnovne hipoteze, materijal i metode.<br />Treće poglavnje sadrži kratak prikaz koštanih tumora i istorijat tumorske<br />endoproteze. Ukazuje se na komplikacije nakon ugradnje kao i na kriterijume za ugradnju<br />tumorske endoproteze. Primarni i sekundarni tumori, neuspela aloartroplastika,<br />prelomi preko ili ispod trohantera, patološki prelom, često prouzrukuju totalno<br />razaranje gornjeg dela butne kosti, i ovi uslovi predstavljaju indikaciju za zamenu<br />gornjeg dela butne kosti tumorskom endoprotezom. Cilj ugradnje tumorske endoproteze<br />zgloba kuka je da se spase ekstremitet, očuva estetika i obezbedi zadovoljavajuća<br />funkcionalnost i neutrališe prisustvo bola. Ne može se očekivati da endoprotetski<br />sistem ima neograničen vek. Za pojedine delove koji su izloženi intenzivnom habanju u<br />toku eksplatacije potrebno je obezbediti mogućnost jednostavne zamene uz minimalan<br />hirurški zahvat.</p><p>Sa biomehaničkog aspekta projektovanja, sistem fiksacije i konfiguracija tela<br />endoproteze mora biti takav da minimizira naponsko stanje ili obezbedi povoljniju<br />raspodelu napona.<br />Četvrto poglavlje je posvećeno definisanju strukture i dimenzija komponenti sistema<br />tumorske modularne endoproteze zgloba kuka. Ukazuje se na postupak i uticajne faktore<br />na proces projektovanja, kao i na pouzdanost projektovanog rešenja. Posebna pažnja je<br />posvećena dimenzionisanju donje komponente endoproteze sa stanovišta pojave<br />koncentracije napona, kao i elementima za vezu i stezanje komponenti u jedinstven<br />mehanički sistem. Dimenzije pojedinih komponenti su definisane na bazi statističkih<br />razultata do sada ugrađenih tumorskih monolitnih endoproteza na IOHB &bdquo;Banjica&ldquo;<br />Beograd.<br />U okviru petog poglavlja, prikazani su rezultati računarske analize statičkog<br />ponašanja tela monolitne, odnosno donje komponente tumorske modularne endoproteze<br />zgloba kuka. Prvo su prikazana preliminarna ipsitivanja pri statičkom opterećenju, i to<br />računarsko simuliranje eksperimentalnih ispitivanja i sama eksperimentalna<br />ispitivanja za obe vrste tumorskih endoproteza. Na bazi ovih rezultata izvršeno je<br />remodelovanje donje komponente i umesto radijusa prelaza između kragne i tela - mesto<br />maksimalnih napona u implantatu, definisan je optimalni bionički profil prelaza.<br />Nakon izrade donjih komponenti od različitih materijala i različitih profila prelaza<br />realizovana su završna ispitivanja komponenti tumorske modularne endoproteze pri<br />statičkom opterećenju. I kod završnog ispitivanja prvo je izvršeno računarsko<br />modelovanje a nakon toga i eksperimentalno ispitivanje. Pri eksperimentalnom<br />ispitivanju meren je napon u jedanaest mernih tačaka po profilu prelaza između kragne<br />i tela. Dobijeni rezultati su poređeni sa računarskim modeliranjem i konstatovano je<br />zadovoljavajuće poklapanje raspodele i maksimalnih napona po profilu prelaza između<br />kragne i tela endoproteze. Za slučaj delovanja dinamičkog opterećenja izvršena su<br />eksperimentalna laboratorijska ispitivanja. Pri ovom ispitivanju definisane su<br />sledeće promenljive: 1. vrsta endoproteze: monolitna i modularna, 2. materijal:<br />superlegure čelika 316LVM i titanijuma Ti6Al4V, 3. oblik prelaza: sa radijusom i<br />optimizirani prelaz. Cilj ovog ispitivanja ja da se utvrdi broj ciklusa koji će dovesti<br />do početka razlabavljenja tela endoproteze pri maksimalnim uslovima opterećenja, tj.<br />da li navedene promenljive daju statistički značajnu razliku u broju ciklusa do pojave<br />razlabavljenja, kasne mehaničke komplikacije koja prethodi lomu usled zamora<br />materijala, ili zahteva reviziju. Pri ovom ispitivanju fizički prototipovi<br />endoproteza su, izloženi jednosmerno promenljivoj sili, Fmax=2500N, amplitude 2000N i<br />frekvencije 15-20 Hz. Vršena je vizuelena kontrola pojave radiolucentne linije između<br />tela endoproteze i koštanog cementa, odnosno kosti, kao pouzdani znak početka<br />razlabavljenja, kao i Rtg snimaka od strane ortopedskih hirurga nakon svakih 500.000<br />ciklusa, za sve uzorke. Analiza rezultata nakon ispitivanja pri dinamičkom opterećenju<br />uzoraka izrađenih od superlegure čelika 316LVM i uzoraka izrađenih od superlegure<br />titanijuma Ti6Al4V ukazuje na visoku pouzdanost odnosno nizak nivo rizika da može doći<br />do razlabavljenja i do pojave loma usled zamora materijala. Profil prelaza sa velikog<br />na mali prečnik za slučaj radijusa i optimizirani bionički profil nisu pokazali<br />značajnu statističku razliku kod ispitivanja pri dinamičkom opterećenju. Na kraju je<br />pojava razlabavlja utvrđivana i inženjerskom metodom. Nakon ispitivanja dinamičkim<br />opterećenjem fizički prototipovi endoproteza su ponovo izloženi statičkom<br />opterećenju i konstatovano je da nema značajnijih promena u raspodeli i vrednostima<br />maksimalnih napona, što ukazuje da nije došlo da pojave razlabavljenja.<br />Kroz šesto poglavlje dat je kratak opis biokompatabilnih materijala, legura čelika<br />316LVM, kobalta CoCrMo, titanijuma Ti6A14V &bdquo;eli&ldquo;, poroznih i keramičkih materijala,<br />materijala od plastične mase, kompozita i bioreseptivih materijala. Nakon toga su<br />prikazani rezultati ispitivanja biokompatabilnosti materijala koji su primenjeni za<br />izradu elemenata modularnog sistema endoproteza. Rezultati ispitivanja su pokazali<br />da materijali i tehnološki proces proizvodnje zadovoljavaju sa stanovišta<br />biokompatabilnosti.<br />Sedmo poglavlje sadrži zaključke, na osnovu rezultata pojedinih poglavlja i<br />izvedenih istraživanja. Nakon toga dati su pravci budućih istraživanja.<br />Osmo poglavlje sadrži pregled korišćene literature, koju čini 68 literaturnih<br />naslova od kojih je najveći broj citiran u radu.</p> / <p>In the first chapter, the need of implant insertion was apostrophed, with the purpose to achieve<br />normal functioning of human locomotory system. On the base of analysis of the number and the<br />structure of implanted hip endoprosthesis during the years 2014. and 2015. at IOHB &ldquo;Banjica&rdquo;,<br />Belgrade, and at Clinical center of Vojvodina, Novi Sad, Clinic of orthopedy and traumatology, it<br />was concluded that the data, related to the number of citizens, show to be similar and<br />comparable with those from the USA.<br />In the second chapter, in the preface section, the systematization of hip endoprosthesis<br />according to the norm ISO 7216 was presented. After that, the results of historical application of<br />modular tumor endoprosthesis was presented. The attention was paid to the description and<br />structure element variants of modular hip endoprosthesis, and also to the analyses of existing<br />prosthesis constructions. The results of up to now conducted research were additionally enriched<br />with patented variants of modular hip endoprosthesis. At the end, based on previously summed<br />knowledge and experiences in the field of development of prosthetic aids, the goal of the<br />research was determined, so as basic hypothesis, materials and methods.<br />Third chapter comprises short description of bone tumors and historic development of tumor<br />endoprosthesis. The complications after implantation were discussed and also the criteria for the<br />implantation of tumor prosthesis. Primary and secondary tumors, failed arthroplasty, fractures<br />across or beneath trochanter and pathologic fractures are frequent causes of total destruction of<br />the upper portion of the femur and require the replacement of it with tumor prosthesis. The aim of<br />hip tumor prosthesis implantation is to save the limb, to preserve esthetic, to provide satisfactory<br />functionality and to neutralize the pain. It is not possible to expect that endoprosthetic system<br />achieves en infinitely long service life. For some of the components, which are during the service<br />exposed to intensive wear and tear, it is necessary to provide the possibility of simple<br />replacement, with the need for a minimal surgical intervention. From the aspect of biomechanical</p><p>design, the fixation system and body configuration of an endoprosthesis must be such, as to<br />minimize stress level and to provide for a convenient stress distribution.<br />The fourth chapter is dedicated to the definition of the structure and components&rsquo; dimensions<br />for a system of modular hip endoprosthesis. It was dealt with the procedure and with the<br />influencefull factors on a design process and also with the reliability of a designed solution.<br />Special care was devoted to the dimensioning of the upper portion of endoprosthesis from the<br />standpoint of stress concentration and to the elements for the connection and joining the<br />elements in a compact mechanical system. The measures of certain components were defined<br />on the base of statistic analysis of up to now implanted monolithic tumor endoprosthesis at IOHB<br />&ldquo;Banjica&rdquo;, Belgrade.<br />Within fifth chapter, the results of computer analysis of static behavior of the body of monolithic<br />component (lower section) of modular tumor hip endoprosthesis was presented. As the first, the<br />results of preliminary examinations with static load were presented, both the computer simulation<br />of experimental testing and the results of real experimental testing, for both types of tumor<br />endoprosthesis. On the base of these results, the remodeling of the lower component was<br />undertaken so that instead of the connection of a collar and the prosthesis body with the shape<br />of a constant radius (the spot with the maximum stress in the prosthesis), an optimal bionically<br />shaped connection was defined. After the production of lower prosthesis components from<br />different materials and with the different shapes, the final examinations of the components of<br />modular tumor hip endoprosthesis under static load were performed. For the final examinations,<br />in the first step also the computer modeling was performed, and consequently experimental<br />testing. When performing experimental testing, the stress level was determined at eleven<br />measuring spots, on the prosthesis section between the collar and the body. Acquired results<br />were compared to the results acquired through computer modeling and an adequate overlapping<br />of stress distribution and maximum stress in the region between the collar and the prosthesis<br />body was detected. For the case of dynamic load, the laboratory experimental examinations<br />were performed. For these examinations the following variables were determined: 1.<br />endoprosthesis type: monolithic and modular, 2. material: steel superalloy 316LVM and of<br />titanium Ti6Al4V, 3. shape of a connection between the collar and prosthesis body: with constant<br />radius and with the optimized shape. The aim of this examination was to determine the number<br />of cycles which would lead to the beginning of the loosening of the prosthesis body under the<br />conditions of maximum load or, with other words, it was to be determined if mentioned variables<br />provide for significant statistic difference in cycle numbers to the point of prosthesis loosening, to<br />the consequent mechanic complication predicting material fatigue failure or demanding surgical<br />revision. When conducting the examination, physical models of endoprosthesis were exposed to<br />the influence of unidirectionally changing force with the parameters of Fmax = 2500N, Fampl =<br />2000N, frequency 15-20 Hz. After every 500.000 load cycles, for all the samples, the appearance<br />of a radiolucent line between the prosthesis body and bone cement and the bone itself, as the<br />reliable sign of the loosening onset, was visually checked on Rtg shots by orthopedic surgeons.<br />The analysis of the results for behavior under dynamic load, for the samples from steel<br />superalloy 316LVM and from titanium Ti6Al4V shows that they posses high reliability and that<br />there is a low probability that the loosening and the fatigue failure will occur. When examined<br />under dynamic load, prosthesis section with the change from small diameter to large diameter,<br />for the case with constant radius and for the case with optimized bionic profile, have not shown<br />statistically significant difference. At the end, the loosening appearance was examined under the<br />application of engineering methods. After exposing the prosthesis to the dynamic load, physical<br />prototypes of prosthesis were anew exposed to static load and it was confirmed that there is no<br />significant change in the distribution and the level of maximum stress, what was the proof that no<br />loosening has occurred.<br />Within the sixth chapter, the short description of biocompatible materials was given, of steel<br />alloy 316LVM, cobalt CoCrMo, titanium Ti6Al4V &ldquo;eli&rdquo;, of porous and ceramic materials, plastic<br />materials, composites and bioreceptive materials. Subsequently, the results of biocompatibility<br />examination of materials which were applied for the production of the elements of modular<br />endoprosthesis system were presented. The acquired results have proved that the materials and<br />the production process are satisfactory from the standpoint of biocompatibility.<br />Seventh chapter comprises the conclusions, based on specific previous chapters and the<br />research results. After that, the suggestions for the future research were outlined.<br />Eight chapter comprises an overview of used literature, with 68 titles, most of which were cited<br />in this work.</p>