Submitted by Onia Arantes Albuquerque (onia.ufg@gmail.com) on 2018-10-30T13:45:30Z No. of bitstreams: 2 Dissertação - Lorena Damasio Cardoso - 2018.pdf: 3279572 bytes, checksum: 019cc5a3b996db0774fcbab0c3c38770 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-10-30T15:16:02Z (GMT) No. of bitstreams: 2 Dissertação - Lorena Damasio Cardoso - 2018.pdf: 3279572 bytes, checksum: 019cc5a3b996db0774fcbab0c3c38770 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-10-30T15:16:02Z (GMT). No. of bitstreams: 2 Dissertação - Lorena Damasio Cardoso - 2018.pdf: 3279572 bytes, checksum: 019cc5a3b996db0774fcbab0c3c38770 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-10-01 / The loss of tissue because of congenital defects, pathological processes or traumas stimulated the development of tissue engineering, with the aim of repairing or replacing damaged tissues or organs. Due to its elastic properties, cartilaginous tissue has been widely used in reconstructive procedures. The use of this tissue as biomaterial mainly aims at maintaining the three-dimensional properties of the matrix, prioritizing structural, mechanical and biological support for the cells and allowing adequate remodeling. The ideal is to obtain a biomaterial with characteristics of biocompatibility, biofunctionality and mechanical resistance. In this sense, treatments were developed in order to minimize possible inflammatory processes and rejection of the biomembrane at the receptor. The aim of this study was to compare the histological changes in elastic cartilages of the external ear of bovines, submitted to different treatments of conservation with chemical treatment by alkaline solution. The samples were cleaned, standardized and divided into control group and treatment groups. The conservation methods were evaluated with supersaturated salt solution, supersaturated sugar solution, glycerine, formalin and alkaline solution. The samples were maintained in storage media for 60 days and in alkaline solution for 72 hours. After, they underwent preparation, analysis and interpretation on histological slides. In each treatment were evaluated microstructureal parameters, as the maintenance of elastic fibers, fundamental amorphous substance and decellularization. When comparing to the other groups, we verified that the cartilages treated in alkaline solution had better decellularization rate, fundamental amorphous substance removal and mantainance of elastic fibers tridimensional structure. For this reason, this group was considered the most effective method in this study. / A perda de tecidos devido a defeitos congênitos, processos patológicos ou traumas estimulou o desenvolvimento da engenharia tecidual com objetivo de reparo ou substituição de tecidos ou órgãos danificados. Devido às suas propriedades elásticas, o tecido cartilaginoso tem sido bastante utilizado em procedimentos reconstrutivos. A utilização deste tecido como biomaterial se dá principalmente pela manutenção das propriedades tridimensionais da matriz, priorizando sustentação estrutural, mecânica e biológica para as células e permitindo remodelamento adequado. O ideal é que se obtenha um biomaterial com características de biocompatibilidade, biofuncionalidade e resistência mecânica. Neste sentido, foram desenvolvidos tratamentos a fim de minimizar possíveis processos inflamatórios e rejeição da biomembrana no receptor. Objetivou-se comparar as alterações histológicas em cartilagens elásticas de orelha externa de bovinos submetidas a diferentes métodos de conservação com tratamento químico por solução alcalina. As amostras passaram por um processo de dissecação e higienização, sendo posteriormente divididas em grupo controle e grupos de tratamentos. Foram avaliados os métodos de conservação com solução supersaturada de sal, solução supersaturada de açúcar, glicerina, formalina e solução alcalina. As amostras foram mantidas em meios de conservação durante 60 dias e em solução alcalina durante 72 horas. Posteriormente passaram por preparação, análise e interpretação em lâminas histológicas. Em cada tratamento foram avaliados parâmetros microestruturais tais como a manutenção de fibras elásticas, substância fundamental amorfa e descelularização. Em comparação aos demais grupos, foi observado que o grupo do tratamento alcalino apresentou maior descelularização, remoção da substância fundamental amorfa e manutenção da estrutura tridimensional das fibras elásticas. Por isso, este grupo foi considerado o método mais efetivo neste estudo.

Automatická segmentace biologických struktur v mikro-CT datech je stále výzvou, protože často objekt zájmu (v našem případě obličejová chrupavka) není charakterizovaný unikátním jasem či ostrými hranicemi. V posledních letech se konvoluční neuronové sítě (CNNs) staly mimořádně populárními v mnoha oblastech počítačového vidění. Konkrétně pro segmentaci biomedicínských obrazů je široce používaná architektura U-Net. Nicméně v případě mikro-CT dat vyvstává otázka, zda by nebylo výhodnější použít 3D CNN. Diplomová práce navrhla CNN architekturu založenou na síti V-Net včetně metodologie pro předzpracování a postprocessing dat. Základní architektura byla dále optimalizována pomocí pokročilých architektonických modifikací jako jsou pyramidální modul dilatovaných konvolucí (ASPP modul), škálovatelná exponenciálně-lineární jednotka (SELU aktivační funkce), víceúrovňová kontrola učení (multi-output supervision) či bloky s hustými propojeními (Dense blocks). Pro učení sítě byly použity moderní přístupy jako zahřívání kroku učení (learning rate warmup) či AdamW optimalizátor. I přes to, že 3D CNN v úloze segmentace obličejové chrupavky nepřekonala U-Net, optimalizace zvýšila medián Dice koeficientu z 69,74 % na 80,01 %. Používání těchto pokročilých architektonických modifikací v dalším výzkumu je proto vřele doporučováno, jelikož můžou být přidány do libovolné architektury typu U-Net a zároveň výrazně zlepšit výsledky.

Les maladies ostéoarticulaires représentent environ 10% de l’ensemble des pathologies identifiées en France chaque année. Ces maladies inflammatoires et dégénératives des articulations sont pour la plupart consécutives au vieillissement ou à un traumatisme et évoluent vers l’usure des cartilages, d’où un handicap sévère. Comme aucun traitement ne permet la réparation totale du tissu cartilagineux, la recherche médicale développe des techniques d’ingénierie tissulaire. Ces techniques utilisent des substrats polymériques et des cellules souches qui sont « contraints » de se développer pour former du tissu cartilagineux. Cependant, ces techniques ne peuvent pas encore être utilisées à l’échelle d’une articulation complète car il n’est pas possible de reproduire ex vivo à grande échelle la structure et les propriétés mécaniques et physicochimiques du cartilage articulaire. Dans ce contexte, les travaux de cette thèse ont permis de développer des matériaux polymères capables d’être implantés à l’échelle macroscopique dans les articulations pathologiques afin de combler l’usure des cartilages. Pour se faire, de nouveaux biomatériaux - hydrogels p(HEMA) - ont été obtenus en contrôlant le caractère hydrophile des hydrogels p(HEMA) au cours de leur synthèse chimique en présence de différents co-monomères (acide acrylique, acrylamide, acrylate d'éthylène et acrylate de butyle). Partant de là, les propriétés physicochimiques, mécaniques et tribologiques de ces nouveaux hydrogels ont été optimisées afin d’obtenir des propriétés similaires à celles du cartilage articulaire sain. Ensuite, la libération contrôlée de médicaments par ces hydrogels a été étudiée afin de minimiser les risques inflammatoires lors de leur utilisation en ingénierie tissulaire du cartilage articulaire. / Osteoarticular diseases re present approximately 10% of all diseases identified in France each year. These inflammatory and degenerative joint disease are mostly consecutive with age or injuries and the wear progress of cartilage, resulting in severe disability. Because no treatment will total repair the cartilage tissue, medical research is developing techniques based on tissue engineering. These techniques use polymer substrates and stem cells that are "forced" to develop into cartilage tissue. However, these techniques cannot be used across a run articulation because Il is not possible-to replicate ex vivo a large-scale structure and the physicochemical and mechanical properties of articular cartilage. In this context, the purpose of this thesis is to develop polymer materials that can be implanted at the macroscopic level in the joints disease that will fill the wear of the cartilage. To do so, new biomaterials - hydrogels p (HEMA)- were obtained by controlling the hydrophilic nature of hydrogels p (HEMA) during their chemical synthesis in the presence of various co-monomers (acrylic acid, acrylamide, acrylate ethylene and butyl acrylate). From there, physicochemical, mechanical and tribological properties of these novel hydrogels have been optimized to obtain similar properties to those of healthy articular cartilage. Then, the controlled release of drugs from these hydrogels was studied to minimize inflammatory when used in tissue engineering of articular cartilage.