Добірка наукової літератури з теми "Adhesive plaque"

Lors de l'assemblage de wafers par adhésion moléculaire, un mince film d'air est piégé entre les deux wafers, créant ainsi un système fluide/structure couplé. La qualité finale de l'assemblage dépend fortement de la dynamique de ce système. L'initiation et la propagation du collage ont été étudiées, en régime transitoire, en utilisant un modèle de plaques minces couplée avec l'équation de Reynolds. La résolution numérique de l'équation, ainsi que la mesure optique du déplacement vertical de la plaquette durant le collage, nous a permis de valider le modèle et de mieux comprendre la dynamique du collage. Dans la continuité de cette étude, nous avons proposé une expression analytique de la courbure finale de l'assemblage en fonction des forces en jeu pendant le collage, ceci en utilisant à nouveau la théorie des plaques minces et en considérant l'existence d'un saut de déformation transverse le long de l'interface collée. Ce modèle a été validé par une expérience, impliquant le collage de wafers d'épaisseur différentes et en prenant soin de contrôler l'ensemble des forces agissant sur ces wafers. Nous observons une influence importante du film d'air sur la forme finale des wafers. En complément, un modèle du travail d'adhésion a été développé prenant en compte, à la fois, la rugosité d'interface et la quantité d'eau adsorbée. La différence de répartition de l'eau à l'interface de collage, nous permet d'expliquer les résultats expérimentaux montrant des valeurs d'énergie de séparation supérieure à celle de l'adhésion. Enfin, nous proposons une nouvelle méthode de mesure du travail d'adhésion pour la géométrie entière des wafers, utilisant la mesure de la taille d'une bulle cylindrique intentionnellement créée, par un petit objet, à l'interface de collage.

Les oligodendrocytes sont les cellules myélinisantes du système nerveux central. La gaine de myéline ainsi que l’oligodendrocyte qui la synthétise, sont les cibles du processus pathologique dans la Sclérose En Plaques (SEP), une maladie neurologique autoimmune et démyélinisante du système nerveux central. Les progrès thérapeutiques des 10-15 dernières années ont permis une meilleure prise en charge de la composante autoimmune de la maladie. En revanche nous sommes toujours aussi démuni pour corriger la composante démyélinisante, qui pourtant est la cause du handicap sensori-moteur permanent. Dans le but de mettre en place des thérapies de réparation myélinique chez les patients atteints de SEP, des efforts sont développés pour identifier des cibles thérapeutiques qui permettraient de contrôler la production et la dispersion des cellules précurseurs d’oligodendrocytes (OPCs) dans la moelle épinière et le cerveau. Le développement embryonnaire et néonatal constitue une période privilégiée pour examiner ces phénomènes. Dans ce contexte, mon travail de thèse a porté sur l’identification de nouvelles molécules contrôlant la spécification régionale et la migration des OPCs ainsi que leur interaction avec les axones dans le système nerveux central en développement chez la souris. Une première contribution, portant sur l’étude de la molécule d’adhésion TAG-1, m’a permis de montrer que TAG-1 régule la structure de la myéline et des axones dans le nerf optique de souris. Dans un deuxième temps, j’ai exploré l’origine des oligodendrocytes dans le tronc cérébral de souris, et mon travail m’a permis de montrer que le facteur de transcription Hoxa2 réprime l’oligodendrogenèse.

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2007.<br>Committee Chair: Mulalo Doyoyo; Committee Co-Chair: Reginald Desroches; Committee Member: Laurence J. Jacobs.

Plaquetas e células tumorais interagem em uma reação cruzada com proteínas do plasma, via integrina &#945;IIb&#946;3 e &#945;v&#946;3, respectivamente. A integrina &#945;v&#946;3 também encontra-se presente na angiogênese tumoral. O objetivo desse trabalho foi avaliar a GST-INS, uma disintegrina recombinante do veneno de Bothrops insularis em eventos da progressão tumoral. Em condições estáticas, GST-INS foi capaz de inibir totalmente a adesão de células HUVECs e SK-MEL-28 às plaquetas em comparação ao controle e ao Aggrastat® (inibidor seletivo da integrina &#945;IIb&#946;3). Além de inibir a TCIPA (agregação plaquetária induzida por células tumorais) a GST-INS também inibiu a invasão de SK-MEL-28 em substrato de matrigel. Células t.End.1 ou SK-MEL-28 pré-incubadas com GST-INS não formaram túbulos no substrato de matrigel. Análise por microscopia confocal mostrou que GST-INS liga-se a integrina &#945;v presente nas células SK-MEL-28. Nossos resultados sugerem que essa disintegrina pode ser utilizada como potencial ferramenta no estudo e desenvolvimento de antiangiogênicos e antimetastáticos.<br>Platelets and tumor cells interact in a cross-react with plasma proteins via integrin &#945;IIb&#946;3 and &#945;v&#946;3 , respectively.The integrin &#945;v&#946;3 is also strongly stimulated in tumor angiogenesis. The aim of this study was to evaluate the ability of GST-INS, a recombinant disintegrin from Bothrops insularis venom on events of tumor progression. Under static conditions, GST-INS was able to completely inhibit the adhesion of endothelial cells (HUVECs) and melanoma cells (SK-MEL-28) to platelets compared to control and Aggrastat® (selective inhibitor of integrin &#945;IIb&#946;3). In addition, GST-INS inhibit TCIPA (platelet aggregation induced by tumor cells) GST-INS also inhibited SK-MEL-28 on matrigel invasion substrate. t.End.1 cells or SK-MEL-28 pre-incubated with GST-INS were not able to form tubules in matrigel substrate. Analysis by confocal microscopy showed that GST-INS binds to integrin &#945;v present in SK-MEL-28 cells. The results suggest that disintegrin can be used as a potential tool in the study and development of antiangiogenic and antimetastatic.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-04-07T17:05:57Z No. of bitstreams: 1 2015 - Gilmar Correia Silva.pdf: 1482826 bytes, checksum: 7a35ec4d7a85ca255722822c502c454d (MD5)<br>Made available in DSpace on 2017-04-07T17:05:57Z (GMT). No. of bitstreams: 1 2015 - Gilmar Correia Silva.pdf: 1482826 bytes, checksum: 7a35ec4d7a85ca255722822c502c454d (MD5) Previous issue date: 2015-05-22<br>CAPES<br>This study aimed to evaluate the quality of panels Pinus caribaea var caribaea produced from lignosulfonato based adhesive (LS), urea formaldehyde (UF) and mixtures thereof, variations in time and pressing temperature. For that, were determined the physical and chemical properties of wood and adhesives, the chemical composition of the LS and its chemical bonds by infrared spectroscopy (IR) and nuclear magnetic resonance (NMR), and pure in composition with different catalysts , the substitution effect of different percentages of UF by LS in the production of panels on the technological properties. They were also produced panels with modified LS acid. The predetermined nominal density of the panels was 0,70g/cm?. LS used in solid form was diluted to 45% in distilled water. The production of the panels was performed in three steps by varying the press temperature (140, 160 and 180?C). In the first step was applied at 140?C for composite panels 100% UF and thereafter was to be replaced by LS in the proportions of 20, 40, 60, 80 and 100%. In a second step, the first step three treatments with results from inferior mechanical properties were tested at temperatures of 160 to 180?C. In the third stage they were produced composite panels only with LS adhesive and acid in the previous three temperatures. The results of basic and apparent wood density were 0,54 and 0,60g/cm?, respectively. The extractive content of the wood was 1,80%, the macromolecular components present in the cell wall of the wood (cellulose, hemicellulose and lignin) followed the standard for the species, and pH and buffering capacity of the timber. NMR analysis showed the same pattern for lignin derivatives in their chemical bonds. Regarding the physical properties of the boards produced at 140?C, smaller percentages of thickness swelling and water absorption were checked in particleboards produced with 100% UF. For mechanical properties, no significant difference occurred between the panels made with 100% UF panels and modified with up to 40% LS. The panels produced with temperatures of 160 and 180?C generate similar results and in most higher in temperature at 180?C. Since the panels produced with LS and acid had generally improved in all properties, especially those with higher temperature<br>O presente trabalho teve como objetivo geral avaliar a qualidade de pain?is aglomerados de Pinus caribaea var. caribaea produzidos a partir de adesivo ? base de lignosulfonato (LS), ureia-formalde?do (UF) e suas misturas, sob varia??es de tempo e temperatura de prensagem. Para tanto, foram determinadas as propriedades f?sicas e qu?micas da madeira e dos adesivos, a composi??o qu?mica elementar do LS e suas liga??es qu?micas por meio da espectroscopia de infravermelho (IV) e resson?ncia magn?tica nuclear (RMN), puro e em composi??o com diferentes catalisadores, o efeito da substitui??o de diferentes porcentagens de UF por LS na produ??o dos pain?is sobre as propriedades tecnol?gicas. Tamb?m foram produzidos pain?is com LS modificados com ?cido. A densidade nominal preestabelecida dos pain?is foi de 0.70 g/cm?. O LS utilizado na forma s?lida foi dilu?do a 45% em ?gua destilada. A produ??o dos pain?is foi realizada em tr?s etapas variando a temperatura de prensagem (140, 160 e 180?C). Na primeira etapa foi aplicada a temperatura de 140?C para pain?is compostos com 100% de UF e a partir da? houve a sua substitui??o por LS nas propor??es de 20, 40, 60, 80 e 100%. Numa segunda etapa, tr?s tratamentos da primeira etapa com resultados de propriedades mec?nicas inferiores foram testados nas temperaturas de 160 e 180?C. Na terceira etapa foram produzidos pain?is compostos apenas com o adesivo LS e ?cido nas tr?s temperaturas anteriores. Os resultados da densidade b?sica e aparente da madeira foram de 0,54 e 0,60g/cm?, respectivamente. O teor de extrativos da madeira foi de 1,80%, os componentes macromoleculares presentes na parede celular da madeira (celulose, hemicelulose e lignina) seguiram o padr?o para a esp?cie, assim como o pH e a capacidade tamp?o da madeira. A an?lise de RMN mostrou o mesmo padr?o para derivados de lignina em suas liga??es qu?micas. Em rela??o ?s propriedades f?sicas dos pain?is produzidos a 140?C foram verificadas porcentagens menores de inchamento em espessura e absor??o de ?gua nos pain?is produzidos com 100% de UF. Para as propriedades mec?nicas, os tratamentos que tiveram composi??o modificada com at? 40% de LS, n?o apresentaram diferen?a significativa com o tratamento produzido com 100% de UF. Os pain?is produzidos com temperaturas de 160 e 180?C geraram resultados similares e na maioria superiores na temperatura de 180?C. J? os pain?is produzidos com LS e ?cido apresentaram em geral, melhoria em todas as propriedades, com destaque para aqueles com maior temperatura.

In this thesis, a number of mathematical models of haptotactic cell migration are developed. The modelling of haptotaxis is presented in two distinct parts - the first comprises an investigation of haptotaxis in pre-necrotic avascular tumours, while the second consists of the modelling of adhesion-mediated haptotactic cell migration within tissue, with particular attention paid to the biological appropriateness of the description of cell-extracellular matrix adhesion. A model is developed that describes the effects of passive and haptotactic migration on the cellular dynamics and growth of pre-necrotic avascular tumours. The model includes a description of the extracellular matrix and its effect on cell migration. Questions are posed as to which cell types act as a source of the extracellular matrix, and the model is used to simulate the possible effects of different matrix sources. Simulations in one-dimensional and spherically symmetric geometry are presented, displaying familiar results such as three-phase tumour growth and tumours comprising a rim of proliferating cells surrounding a non-proliferating region. Novel effects are also described such as cell population splitting and tumour shrinkage due to haptotaxis and appropriate extracellular matrix construction. The avascular tumour model is then extended to describe the internalisation of labelled cells and inert microspheres within multicell tumour spheroids. A novel model of adhesion-receptor mediated haptotactic cell migration is presented and specific applications of the model to tumour invasion processes are discussed. This model includes a more biologically realistic description of cell adhesion than has been considered in previous models of cell population haptotaxis. Through assumptions of fast kinetics, the model is simplified with the identification of relationships between the simplified model and previous models of haptotaxis. Further simpli.cations to the model are made and travelling wave solutions of the original model are then investigated. It is noted that the generic numerical solution routine NAG D03PCF is not always appropriate for the solution of the model, and can produce oscillatory and inaccurate solutions. For this reason, a control volume numerical solver with .ux limiting is developed to provide a better method of solving the cell migration models.

Since their accidental introduction into the Great Lakes in mid- to late-1980s, the freshwater zebra mussels, Dreissena polymorpha, have colonized most lakes and waterways across eastern North America. Their rapid spread is partly attributed to their ability to tenaciously attach to hard substrates via an adhesive apparatus called the byssus, resulting in serious environmental and economic impacts. A detailed ultrastructural study of the bysuss revealed a 10 nm adhesive layer at the attachment interface. Distributions of the main adhesive amino acid, 3,4-dihydroxyphenylalanine (DOPA), and its oxidizing (cross-linking) enzyme, catechol oxidase, were determined histochemically. It was found that, upon aging, DOPA levels remained high in the portion of the byssus closest to the interface, consistent with an adhesive role. In contrast, reduced levels of DOPA corresponded well with high levels of catechol oxidase in the load-bearing component of the byssus, presumably forming cross-links and increasing the cohesive strength.