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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Retained Placenta and Postpartum Haemorrhage

Belachew, Johanna January 2015 (has links)
The aim was to explore the possibility to diagnose retained placental tissue and other placental complications with 3D ultrasound and to investigate the impact of previous caesarean section on placentation in forthcoming pregnancies. 3D ultrasound was used to measure the volumes of the uterine body and cavity in 50 women with uncomplicated deliveries throughout the postpartum period. These volumes were then used as reference, to diagnose retained placental tissue in 25 women with secondary postpartum haemorrhage. All but three of the 25 women had retained placental tissue confirmed at histopathology. The volume of the uterine cavity in women with retained placental tissue was larger than the reference in most cases, but even cavities with no retained placental tissue were enlarged (Studies I and II). Women with their first and second birth, recorded in the Swedish medical birth register, were studied in order to find an association between previous caesarean section and retained placenta. The risk of retained placenta with heavy bleeding (>1,000 mL) and normal bleeding (≤1,000 mL) was estimated for 19,459 women with first caesarean section delivery, using 239,150 women with first vaginal delivery as controls. There was an increased risk of retained placenta with heavy bleeding in women with previous caesarean section (adjusted OR 1.61; 95% CI 1.44-1.79). There was no increased risk of retained placenta with normal bleeding (Study III). Placental location, myometrial thickness and Vascularisation Index were recorded on 400 women previously delivered by caesarean section. The outcome was retained placenta and postpartum haemorrhage (≥1,000 mL). There was a trend towards increased risk of postpartum haemorrhage for women with anterior placentae. Women with placenta praevia had an increased risk of retained placenta and postpartum haemorrhage. Vascularisation Index and myometrial thickness did not associate (Study IV). In conclusion: 3D ultrasound can be used to measure the volume of the uterine body and cavity postpartum, but does not increase the diagnostic accuracy of retained placental tissue. Previous caesarean section increases the risk of retained placenta in subsequent pregnancy, and placenta praevia in women with previous caesarean section increases the risk for retained placenta and postpartum haemorrhage.
2

Arte, tecnica e estetica / Art, technique and aesthetics research

Chaves Junior, Cassimiro Carvalho, 1982- 15 August 2018 (has links)
Orientador: Ernesto Giovanni Boccara / Acompanha 01 CD-ROM / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Artes / Made available in DSpace on 2018-08-15T02:05:54Z (GMT). No. of bitstreams: 1 ChavesJunior_CassimiroCarvalho_M.pdf: 3615358 bytes, checksum: 3fd2ba2a6fe86be9be825a017c488441 (MD5) Previous issue date: 2009 / Resumo: O projeto tem o intuito de realizar uma investigação sobre o domínio da Animação Cinematográfica. No capítulo 1, há uma investigação sobre a Animação Cinematográfica, traçando um parâmetro histórico de sua criação, evolução e suas referências estéticas, divididas sobre a nomenclatura "Escolas Estilísticas. Para fechar o capítulo, uma contextualização de dois filmes, que seguiam os padrões analisados. No capítulo 2, discute-se o processo evolutivo da Animação Cinematográfica, entendendo os paradigmas acerca das técnicas e tecnologias; Assim, numa combinação de técnicas, selecionei o filme "Horton e o Mundo dos Quem", por ter a estética bem elaborada, construindo dois mundos distintos que interagem de maneira singular. No capítulo 3, examina-se os processos preciosos na confecção de produções em Animação que utilizam a perspectiva tridimensional como fator estético e artístico. Há um primeiro recorte possível neste capítulo, ligado às técnicas de animações que utilizam a modelagem em "massinha", utilizando como fator analítico filme "A Noiva Cadáver". O segundo recorte possível, deste capítulo, são as possibilidades técnicas de animação digital, então selecionei o filme "A Casa Monstro", pois, trata-se de uma elaboração tecnológica sofisticada para constituir uma estória contundente e um enredo substancioso. No capítulo 4, chequei as conclusões possíveis acerca do passado, presente e futuro da Animação Cinematográfica, seja quanto aos aparatos técnicos de exibição ou a inserção de novas tecnologias na construção de estórias concisas. Para isso, articulei as tensões entre arte, técnica e estética como causa e reciprocidade entre elas para entender a formação e os pontos convergentes a identificação dos espectadores. / Abstract: The project aims to conduct research on the field of Animation Film. In Chapter 1, there is an investigation into the Animation Film, tracing a historical parameter of its creation, evolution and their aesthetic references, divided on the nomenclature "stylistic schools. To close the chapter, a background of two films that followed the patterns analyzed. Chapter 2 discusses the evolution of the Animation Film, understanding the paradigms of techniques and technologies; Thus, a combination of techniques, I selected the movie "Horton Hears a Who" for having a well-crafted aesthetic, building two different worlds that interact in unique ways. In chapter 3, examines the processes in the manufacture of precious productions animation using three-dimensional perspective as artistic and aesthetic factor. There is a possible angle in this first chapter, on the techniques of animation using the modeling "clay", using factor analytic film "Corpse Bride". The second possible angle, this chapter, the technical possibilities of digital animation, so I selected the movie "Monster House," because it is a sophisticated technological development to provide a compelling story and a substantial plot. In Chapter 4, I checked the possible conclusions about the past, present and future of Animation Film, is about the technical apparatus of view or the insertion of new technologies in the construction of concise stories. For this, articulated the tensions between art, technology and aesthetics as cause and reciprocity between tem to understand the formation and the similarities identification of spectators. / Mestrado / Mestre em Multimeios
3

Méthodes numériques adaptées à la résolution des équations de Navier-Stokes / Numerical methods suitable for solving the Navier-Stokes equations

Guevel, Yann 15 January 2016 (has links)
Le groupe de recherche Instabilités et Méthodes Numériques Spécifiques mène ses activités dans le développement d’outils numé- riques pour la résolution de problèmes non linéaires en utilisant, no- tamment, la Méthode Asymptotique Numérique (MAN). Basée sur le couplage d’une méthode de perturbation et de discrétisation spa- tiale, la MAN est efficace et permet de déterminer précisément les transitions telles que, par exemple, la perte d’unicité de la solution. L’objectif de ce travail de thèse est de proposer des méthodes numé- riques alternatives à la fois robustes, performantes pour la résolution des équations de Navier-Stokes. Nous nous intéressons à l’analyse de bifurcation stationnaire, mais aussi à la simulation d’écoulement dépendant du temps. Dans un premier temps, des techniques d’analyse de bifurcation nu- mérique pour des problèmes stationnaires à très grand nombre de degrés de liberté sont décrites. Nous implémentons ces techniques, basées sur la MAN, dans le logiciel open-source multi-physique ELMER . Nous détaillons l’implémentation des méthodes d’analyse de bifurcation stationnaire telles que la continuation de branches solutions, les techniques de détection des valeurs critiques du pa- ramètre de charge et les changements de branche en un point de bifurcation stationnaire. L’émergence d’une progression géométrique dans les termes de séries MAN à l’approche d’une singularité est dé- crite. Des discussions sont proposées pour le cas de bifurcations par brisure de symétrie. Les méthodes proposées dans ce travail sont validées en utilisant des cas référencés dans la littérature, tels que des écoulements dans des conduites à expansion/contraction sou- daine. Une étude paramétrique permet de présenter de nouveaux ré- sultats pour les écoulements tridimensionnels dans une expansion brusque. L’utilisation de librairies de calculs intensifs rend possible la réalisation d’analyse de bifurcation pour des modèles à très grand nombre de degrés de liberté, en des temps de calcul abordables. Dans un deuxième temps, des solveurs d’ordre élevé sont proposés pour la simulation d’écoulements instationnaires. Une technique d’homotopie à combinaison convexe et une technique de pertur- bation, sont couplées à un schéma d’intégration temporelle pour résoudre les équations instationnaires de Navier-Stokes. Le cas d’un écoulement bidimensionnel autour d’un cylindre fixe est étudié. Ce problème de référence nous permet de valider et discuter des amélio- rations proposées. De cette manière, nous confirmons, au cours des essais numériques, qu’il est possible de réduire les temps de cal- cul en évitant des assemblages d’opérateurs et des résolutions de systèmes linéaires qui n’apportent aucune information supplémen- taire pour la qualité des solutions. De plus, un nouvel éclairage est apporté sur l’utilisation des approximants de Padé par rapport aux travaux antérieurs. L’utilisation de ces solveurs non linéaires nous permet de réduire significativement le nombre de factorisations de matrice en les conservant valides pour un grand nombre de pas de temps, et parfois sur le domaine temporel complet. De nombreuses perspectives sont envisagées, notamment pour l’analyse des séries pour le cas d’un point limite, la bifurcation de Hopf, l’étude d’autre cas d’écoulements tridimensionnels, le couplage fluide-structure. De même, l’association des techniques MAN aux techniques de réductions de modèles et l’analyse de stabilité des orbites périodiques sont envisageables. / The research group "Instabilités et Méthodes Numériques Spéci-fiques" operates in the development of numerical tools for solving nonlinear problems by using, in particluar, the Asymptotic Numer- ical Method (ANM). Based on coupling a perturbation method and a spatial discretization, the ANM is effective and makes it possible to precisely determine the transitions such as, for example, loss of uniqueness of the solution. The objective of this thesis is to offer al- ternative numerical methods both robust and effective, for solving the Navier-Stokes equations. We are interested in steady bifurcation analysis, and in time dependent flow simulation .Initially, numerical bifurcation analysis techniques for steady flow problems in very large number of degrees of freedom are de- scribed. These techniques, based on the ANM, are implemented in the multiphysics ELMER open-source software. We detail the im- plementation of the steady bifurcation analysis methods such as continuation of solution branches, detection of load parameter critical values and branch switching at steady bifurcation point. The emer- gence of a geometric progression in ANM series terms in the vicinity of a singularity is described. Discussions are proposed for the case of symmetry breaking bifurcations. The methods described in this the- sis are validated using reference cases of the literature, such as flow in pipe with sudden expansion/contraction. New results for three- dimensional flow in a sudden expansion, are obtained according to a parametric study. The use of high performance computing libraries makes possible the bifurcation analysis for models with high number of degrees of freedom, in affordable computing times. Secondly, high-order solvers are proposed for the simulation of un- steady flows. Homotopy with convex combination and a perturba- tion technique, are coupled to a time integration scheme in order to solve the unsteady Navier-Stokes equations. The case of two- dimensional flow around a fixed cylinder is studied. This reference problem allows us to validate and discuss proposed improvements. In this way, we confirm, in the numerical tests, that it is possible to reduce the computation time by avoiding operators assembly and resolution of unuseful linear systems in respect to the solution quality. In addition, new lighting is provided on the use of Padé approximants over previous work. The use of these nonlinear solvers allows us to significantly reduce the number of matrix factorization retaining them valid for many time steps, and sometimes on the complete time do- main. Many opportunities are envisaged, in particular the analysis of ANM series for the case of limit point, the Hopf bifurcation, the study of other cases of three-dimensional flow, the fluid-structure interaction. Similarly, the combination of ANM models with reduction techniques f stable periodic orbits are possible.
4

Detecção e desvio de obstáculos para veículos aéreos não tripulados usando visão monocular / Obstacle avoidance for UAVs using monocular vision

Chiaramonte, Rodolfo Barros 21 November 2018 (has links)
Veículos autônomos são importantes para a execução de missões dos mais variados tipos, reduzindo riscos aos seres humanos e executando as missões de uma maneira mais eficiente. Neste contexto existem os veículos aéreos não tripulados que são cada vez mais utilizados em missões de vigilância, reconhecimento, resgate, entre outras. Uma das características destes veículos é realizar as missões de maneira autônoma, sem a intervenção de operadores humanos. Desta forma, é necessário que existam formas de detectar aproximações perigosas com outras aeronaves e objetos que possam causar risco de colisão e, consequentemente a perda de ativos de alto valor ou até mesmo vidas humanas e, posteriormente realizar o desvio necessário. Neste cenário foi proposto o MOSAIC, um sistema de detecção e desvio de obstáculos utilizando visão monocular para veículos aéreos de pequeno porte. Para isto, foi desenvolvido um método de estimativa da posição tridimensional dos obstáculos a partir de imagens monoculares e propostas melhorias em algoritmos de detecção. A validação do sistema foi obtida por meio de experimentos simulados e reais sobre cada módulo e os resultados obtidos foram promissores, apresentando um erro de apenas 9,75% em ambientes sem restrições e distâncias de até 20 metros. Com isto, os resultados se mostram melhores que os demais algoritmos encontrados no estado da arte em que o erro é menor que 10% apenas em ambientes controlados e distâncias de até 5 metros. / Autonomous vehicles can be used for different kinds of missions reducing risks to human life and being more efficient. In this context, unmanned aerial vehicles play an important role on surveillance, recognition and rescue missions, among others. Due to the mission nature, these vehicles need to perform actions without human intervention, which requires that dangerous approximations to others aerial vehicles or objects to be detected and properly avoided. This leads to the creation of MOSAIC, an obstacle avoidance system based on monocular vision designed to meet the requirements of miniature air vehicles. A novel approach to estimate obstacle three-dimensional position based on monocular vision was developed and some improvements in the detection algorithm were proposed. The system validation was obtained through simulated and real experiments in which each module could be validated. Promising results were obtained showing an error under 9.75% in unconstrained environments and distance up to 20 meters. This results were better than the algorithms and approaches described in the state of the art where errors are under 10% only on constrained environments and distance up to 5 meters.
5

Detecção e desvio de obstáculos para veículos aéreos não tripulados usando visão monocular / Obstacle avoidance for UAVs using monocular vision

Rodolfo Barros Chiaramonte 21 November 2018 (has links)
Veículos autônomos são importantes para a execução de missões dos mais variados tipos, reduzindo riscos aos seres humanos e executando as missões de uma maneira mais eficiente. Neste contexto existem os veículos aéreos não tripulados que são cada vez mais utilizados em missões de vigilância, reconhecimento, resgate, entre outras. Uma das características destes veículos é realizar as missões de maneira autônoma, sem a intervenção de operadores humanos. Desta forma, é necessário que existam formas de detectar aproximações perigosas com outras aeronaves e objetos que possam causar risco de colisão e, consequentemente a perda de ativos de alto valor ou até mesmo vidas humanas e, posteriormente realizar o desvio necessário. Neste cenário foi proposto o MOSAIC, um sistema de detecção e desvio de obstáculos utilizando visão monocular para veículos aéreos de pequeno porte. Para isto, foi desenvolvido um método de estimativa da posição tridimensional dos obstáculos a partir de imagens monoculares e propostas melhorias em algoritmos de detecção. A validação do sistema foi obtida por meio de experimentos simulados e reais sobre cada módulo e os resultados obtidos foram promissores, apresentando um erro de apenas 9,75% em ambientes sem restrições e distâncias de até 20 metros. Com isto, os resultados se mostram melhores que os demais algoritmos encontrados no estado da arte em que o erro é menor que 10% apenas em ambientes controlados e distâncias de até 5 metros. / Autonomous vehicles can be used for different kinds of missions reducing risks to human life and being more efficient. In this context, unmanned aerial vehicles play an important role on surveillance, recognition and rescue missions, among others. Due to the mission nature, these vehicles need to perform actions without human intervention, which requires that dangerous approximations to others aerial vehicles or objects to be detected and properly avoided. This leads to the creation of MOSAIC, an obstacle avoidance system based on monocular vision designed to meet the requirements of miniature air vehicles. A novel approach to estimate obstacle three-dimensional position based on monocular vision was developed and some improvements in the detection algorithm were proposed. The system validation was obtained through simulated and real experiments in which each module could be validated. Promising results were obtained showing an error under 9.75% in unconstrained environments and distance up to 20 meters. This results were better than the algorithms and approaches described in the state of the art where errors are under 10% only on constrained environments and distance up to 5 meters.
6

3D Visualized Indoor Positioning System

Xia, Ziqi, Mani Alvandian, Sohrab January 2018 (has links)
Three-dimensional visualization refers to the process by which graphical content is created using the Three-dimensional software. While working with Threedimensional visualization, different indoor positioning techniques can be used to detect and track the movement of objects. Combining these two technologies provide the ability to monitor a room and its objects in real time. Positioning is the process of recording the movement of objects or people. Positioning techniques can be used in many different areas such as emergent situations and tracking objects with potential risks as an aid. It is not self-evident how well this kind of a system would work in the given contexts. To address this, the method has consisted of a literature study focused on existing theories of positioning and different factors that affect the positioning outcome and a case study on positioning systems in a number of existing indoor positioning systems. The purpose of this project is to present and evaluate a prototype where an indoor positioning system will be combined with a specific platform which works with simple types of hardware signals to generate three-dimensional models. The goal is to present a system that will have the ability to be used without any infrastructure or external hardware. Different indoor positioning systems will be analyzed as well as their use in various scenarios. This thesis evaluates various technical choices, and provides an overview of some of the existing wireless indoor positioning solutions and the theory and methods used, before describing the case study, including the development process, problems faced, the result, and the experimental testing results. In conclusion, the thesis presents a prototype which is validated to fulfill the basic expectation of a three-dimensional visualized indoor positioning system. / Tredimensionell visualisering refererar till processen genom vilken grafisk innehåll skapas med hjälp av tredimensionell programvara. Under arbetet med tredimensionell visualisering kan olika inomhus positioneringstekniker användas för att upptäcka och spåra rörelser av object. Kombinationen av dessa två tekniker ger möjlighet att övervaka ett rum och dess föremål i realtid. Positionering är processen att spela in rörelser av objekt eller personer. Positionering kan användas i många olika områden såsom nödsituationer och spårning av föremål eller brandmän i enbyggnad som brinner eller detektering av polishundar som är utbildade för att hitta sprängämnen i en byggnad. Det är inte självklart hur bra ett sådant system skulle fungera i de givna sammanhangen. För att ta itu med detta, har metoden bestått av en litteraturstudie inriktat på befintliga teorier om positionering, olika faktorer som påverkar positionerings resultatet samt en fallstudie om positioneringssystem i ett antal befintliga inomhus positioneringssystem. Syftet med detta projekt är att presentera och utvärdera en prototyp där ett inomhuspositioneringssystem kombineras med en specifik plattform som arbetar med enkla typer av hårdvaru signaler för att generera tredimensionella modeller. Målet är att presentera ett system som kommer kunna användas utan någon infrastruktur eller extern hårdvara. Olika inomhus positioneringssystem kommer att analyserar såväl som deras användning i olika scenarier. Denna avhandling utvärderar olika tekniska val och ger en översikt över några av de befintliga trådlösa inomhuspositioneringlösningarna och ger teorin och metoderna, innan fallstudien beskrivs, inklusive: utvecklingsprocessen, problem, resultat och experimentella testresultat. Sammanfattningsvis presenterar avhandlingen en prototyp som valideras för att uppfylla de grundläggande förväntningarna för ett tredimensionellt visualiserat inomhus positioneringssystem.
7

Referências cefalométricas tridimensionais da simetria dentoesquelética / Three-dimensional cephalometric reference of dentoskeletal symmetry

Porto, Olavo Cesar Lyra 01 November 2012 (has links)
Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2014-10-14T12:59:09Z No. of bitstreams: 2 Dissertacao - Olavo Cesar Lyra Porto - Ciencias da Saude.pdf: 4368065 bytes, checksum: a20fe24dfaac1aa5700048dbfddaf49d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-10-17T21:35:10Z (GMT) No. of bitstreams: 2 Dissertacao - Olavo Cesar Lyra Porto - Ciencias da Saude.pdf: 4368065 bytes, checksum: a20fe24dfaac1aa5700048dbfddaf49d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-10-17T21:35:10Z (GMT). No. of bitstreams: 2 Dissertacao - Olavo Cesar Lyra Porto - Ciencias da Saude.pdf: 4368065 bytes, checksum: a20fe24dfaac1aa5700048dbfddaf49d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2012-11-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Objective: To evaluate dentoskeletal symmetry in cone beam computed tomography (CBCT) scans of Brazilian individuals with Angle class I malocclusion. Materials and methods: Forty seven patients (22 girls) aged 11 to 16 years (14 years) seen in a private radiology service (CIRO, Goiânia, GO, Brazil). All the CBCT images were acquired from January 2009 to December 2010. Cephalometric measurements were made by multiplanar reconstructions (axial, coronal and sagittal) using Vista Dent3DPro 2.0 (Dentsply GAC, New York, USA). The minimum, maximum, mean and standard deviation values were described in tables, and the Student t test was used to define statistical significance (p<0.05). Results: Data were homogeneous, and the differences between right and left sides were not significant. Conclusion: The cephalometric measures of Brazilian individuals with Angle class I malocclusion can be used to define facial symmetry and three-dimensional standard references, which might be useful for orthodontic and surgical planning. / Objetivo: verificar a simetria facial e dentoesquelética por meio de fotografia frontal e tomografia computadorizada de feixe cônico, respectivamente, em indivíduos brasileiros portadores de má oclusão Classe I de Angle. Material e Método: a amostra do estudo foi selecionada de um banco de imagens de 47 pacientes (22 mulheres e 25 homens) com idade entre 11 e 16 anos em um serviço privado de radiologia. Todas as imagens foram obtidas de pacientes com indicação de tratamento ortodôntico no período de janeiro de 2009 a dezembro de 2010. Medidas cefalométricas foram obtidas por meio de reconstruções multiplanares (axial, coronal e sagital) com auxilio do programa Vista Dent3DPro 2.0. O valor mínimo, o máximo, a média e o desvio-padrão das medidas foram determinados e a diferença estatística entre as medidas do lado esquerdo e direito foi analisada por meio do teste-t e Mann-Whitney. Foram considerados significativos valores de p < 0,05. Resultados: As medidas cefalométricas mostraram dados homogêneos. O lado direito e esquerdo exibiram variações nas análises cefalométricas tridimensionais. 61,70% dos pacientes foram considerados simétricos na avaliação fotográfica frontal. Conclusão: Indivíduos brasileiros com classe I de Angle apresentaram simetria facial na maioria dos pacientes, com variações entre o lado direito e esquerdo.
8

Developing an XML-based, exploitable linguistic database of the Hebrew text of Gen. 1:1-2:3

Kroeze, J.H. (Jan Hendrik) 28 July 2008 (has links)
The thesis discusses a series of related techniques that prepare and transform raw linguistic data for advanced processing in order to unveil hidden grammatical patterns. A threedimensional array is identified as a suitable data structure to build a data cube to capture multidimensional linguistic data in a computer's temporary storage facility. It also enables online analytical processing, like slicing, to be executed on this data cube in order to reveal various subsets and presentations of the data. XML is investigated as a suitable mark-up language to permanently store such an exploitable databank of Biblical Hebrew linguistic data. This concept is illustrated by tagging a phonetic transcription of Genesis 1:1-2:3 on various linguistic levels and manipulating this databank. Transferring the data set between an XML file and a threedimensional array creates a stable environment allowing editing and advanced processing of the data in order to confirm existing knowledge or to mine for new, yet undiscovered, linguistic features. Two experiments are executed to demonstrate possible text-mining procedures. Finally, visualisation is discussed as a technique that enhances interaction between the human researcher and the computerised technologies supporting the process of knowledge creation. Although the data set is very small there are exciting indications that the compilation and analysis of aggregate linguistic data may assist linguists to perform rigorous research, for example regarding the definitions of semantic functions and the mapping of these functions onto the syntactic module. / Thesis (PhD (Information Technology))--University of Pretoria, 2008. / Information Science / unrestricted
9

Devenir des cellules souches mésenchymateuses humaines dans un environnement tridimensionnel : application à l’ingénierie du tissu osseux / Become of human mesenchymal stem cells in a three dimensional environment : application to bone tissue engineering

Guerrero, Julien 13 November 2014 (has links)
L’ingénierie tissulaire osseuse a pour objectif de repousser les limitesexistantes de la régénération osseuse. Les stratégies proposées consistent àassocier à une matrice tridimensionnelle (3D) des cellules autologues, capables derégénérer en 3D un tissu fonctionnel. Le but de ce travail a été d’étudier l’importancede la communication cellulaire entre les cellules du compartiment stromal et lescellules endothéliales au sein d’une matrice tridimensionnelle poreuse constituée depolysaccharides naturels biodégradables. Nos résultats montrent que l’architecture etla nature de cette matrice permettent de guider la différenciation ostéoblastique descellules humaines mésenchymateuses issues de la moelle osseuse. L’organisationcellulaire en agrégats observée stimule les interactions cellulaires, et plusparticulièrement la formation de jonctions communicantes de type GAP et l’activitédes Connexines 43. Nous avons en également étudié la fonction des Pannexines 1et 3 dans la culture 3D. En conclusion, l’ensemble de nos travaux démontre que lesinteractions cellule-cellule constituent des événements majeurs dans cesmécanismes de régénération tissulaire. Les données cellulaires et expérimentalestémoignent de l’intérêt d’utiliser la totalité de la suspension de moelle osseuse pourfavoriser à la fois l’ostéoformation et la vascularisation du tissu. / Bone tissue engineering aims to resolve the existing limitations of boneregeneration methods. One of the proposed strategies consists on the association,within a three-dimensional (3D) matrix, with autologous cells able to regenerate afunctional 3D tissue. The purpose of this study was therefore to investigate theimpact of cellular communication, between cells of the stromal compartment andendothelial cells, within the three-dimensional porous matrix made of biodegradablenatural polysaccharides, focusing on bone repair. Our results show that thearchitecture and the nature of the 3D macroporous matrix promotes the guidance ofmesenchymal stems cells, derived from human bone marrow, towards theosteoblastic lineage. Also, that the organization in aggregates, promoted by the 3Dmatrices, stimulated cell communication, evidenced by the formation of GAPjunctions and activity of Connexins 43. We also focused on the function ofPannexines 1 and 3 for the 3D culture in these matrices of polysaccharides. Inconclusion, this work shows that cell-cell interactions play a major role in order toimprove bone tissue regeneration. Also, cellular and experimental data demonstratesthe advantage of using a total fraction of bone marrow cells to promote both boneformation and vascularization.
10

Avaliação da relação entre os índices vasculares placentários e a exposição individual à poluição atmosférica no primeiro trimestre / Evaluation of the placental vascular indices and individual exposure to air pollution in the first trimester

Karen Hettfleisch 17 February 2016 (has links)
OBJETIVO: Avaliar a influência dos efeitos da poluição atmosférica sobre o volume e a vascularização placentários no primeiro trimestre. MÉTODOS: O presente estudo é uma coorte prospectiva  realizada de outubro de 2011 a março de 2014, em São Paulo, Brasil. Os critérios de inclusão foram: feto único, idade gestacional entre 11 semanas e 13 semanas e 6 dias, ausência de doença materna, ausência de malformações e utilização correta do amostrador passivo individual de poluentes. Os critérios de exclusão foram: gestação gemelar, malformações e abortamento diagnosticados à ultrassonografia, mudança de endereço para fora da área de recrutamento, desistência da paciente, doença materna diagnosticada durante o acompanhamento. A exposição à poluição foi avaliada por 7 a 18 dias, antes da avaliação ultrassonográfica, utilizando-se amostrador passivo individual dos poluentes NO2 e de O3. Após uso do filtro, as gestantes eram avaliadas na Clínica Obstétrica do Hospital das Clínicas da Faculdade de Medicina de São Paulo (FMUSP). Nesse local, elas foram submetidas à ultrassonografia morfológica entre 11 semanas e 13 semanas e 6 dias e à avaliação placentária pela técnica tridimensional associada ao power Doppler. Por meio desse exame foram avaliados quantitativamente o volume da placenta e seus índices vasculares placentários (com o software VOCAL), os quais compreendem: índice de vascularização (IV), índice de fluxo (IF) e índice de vascularização e fluxo (IVF). A influência dos níveis de poluentes na vascularização e volume placentários log-transformada foi analisada utilizando modelos de regressão linear múltipla que controlavam a idade gestacional, índice de massa corpórea, tabagismo, localização da placenta e paridade. RESULTADOS: Foram avaliadas 229 gestantes no primeiro. O aumento dos níveis de NO2 no primeiro trimestre teve um efeito negativo significativo sobre o IV (p = 0,012 e beta = 0,160) e IVF (p = 0,015 e beta = -0,159). Não houve influência de NO2 e O3 no volume placentário ou IF. CONCLUSÃO: A exposição materna ao NO2 foi significativamente associada com diminuição do índice de vascularização e do índice de vascularização e fluxo no primeiro trimestre da gravidez, o que sugere que esse poluente e outros poluentes primários e secundários, os quais estão associados ao NO2, influenciam na placentação, reduzindo sua vascularização / OBJECTIVE: To evaluate the influence of air pollution on the volume and placental vascularization in the first trimester. METHODS: This study is a prospective cohort conducted from October 2011 to March 2014 in São Paulo, Brazil. The inclusion criteria were single fetus, gestational age between 11 weeks and 13 weeks and 6 days, the absence of maternal disease, fetal defects and correct use of passive personal monitors pollutants. The exclusion criteria were twin pregnancy, abortion and malformations diagnosed on ultrasound, change of address out of the area of recruitment, patient abandonment, and maternal disease diagnosed during follow-up. The pollution exposure was evaluated by 7 to 18 days, before the ultrasound evaluation, using passive personal monitors pollutants of NO2 and O3. After using the filter, the pregnant women were evaluated at Obstetrics Department from Hospital das Clinicas of Faculdade de Medicina de São Paulo (FMUSP). In this place, they were subjected to morphological ultrasound between 11 weeks and 13 weeks and 6 days and placental evaluation by the three dimensional ultrasound power Doppler. Through the ultrasound examination were quantitatively evaluated the volume of the placenta and their placental vascular indices (with VOCAL software), which comprise the vascularization index (VI), flow index (FI) and vascularization flow index (VFI). The influence of pollutant levels on logtransformed placental vascularization and volume was analyzed using multiple linear regression models that controlled for gestational age, body mass index, smoking status, placental location and parity. RESULTS: In the first trimester 229 pregnant women were evaluation. NO2 levels increased in the first trimester had a significant negative effect on the VI (p=0.012 and beta= -0.160) and the VFI (p = 0.015 and beta= -0.159). No effect of NO2 and O3 on the log of placental volume or FI was observed. CONCLUSION: NO2 exposure was significantly associated with a diminished Vascularization Index and Vascularization and Flow Index in the first trimester of pregnancy, which suggests that this pollutant and other primary and secondary pollutants that are associated with NO2 influence placentation and decrease vascularization

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