published_or_final_version / Anatomy / Master / Master of Philosophy

Retinal detachment (RD) is a leading cause of blindness and although final surgical reattachment rate has greatly improved, visual outcome in many macula-off detachments is disappointing, mainly because of photoreceptor cell death. We previously showed that both lutein and Lycium barbarum polysaccharides (LBP) are neuroprotective in a rodent model of ischemia/reperfusion injury. The objective of this study is to investigate lutein and LBP as possible pharmacological adjuncts to surgery. Lutein: Subretinal injections of 1.4% sodium hyaluronate were used to induce RD in Sprague-Dawley rats until their retinae were approximately 70% detached. Daily injections of corn oil (control group) or 0.5mg/kg lutein in corn oil (treatment group) were given intraperitoneally starting 4 hours after RD induction. Animals were euthanized 3 days and 30 days after RD and their retinae were analyzed for photoreceptor apoptosis and cell survival at the outer nuclear layer (ONL) using TUNEL staining and cell counting on retinal sections. Glial fibrillary acidic protein (GFAP) and rhodopsin (RHO) expression were evaluated with immunohistochemistry. Western blotting was done with antibodies against cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9 to delineate lutein’s mechanism of action in the apoptotic cascade. To seek a possible therapeutic time window, the same set of experiment was repeated with treatment commencing 36 hours after RD. When lutein was given 4 hours after RD, there was significantly fewer TUNELpositive cells in ONL 3 days after RD when compared with the vehicle group. Cell counting showed that there were significantly more nuclei in ONL in lutein-treated retinae by day 30. Treatment groups also showed significantly reduced GFAP immunoreactivity and preserved RHO expression. At day 3 after RD, Western blotting showed reduced expression of cleaved caspase-3 and cleaved caspase-8 in the treatment group. No difference was found for cleaved caspase-9. When lutein was given 36 hours after RD similar results were observed. Our results suggest that lutein is a potent neuroprotective agent that can salvage photoreceptors in rats with RD, with a therapeutic window of at least 36 hours. The use of lutein in patients with RD may serve as an adjunct to surgery to improve visual outcomes. LBP: The same RD model was used for the LBP experiment. Phosphate buffered solution (PBS) or LBP in PBS was given orally through a gavage at 1mg/kg and 10mg/kg concentrations. For this experiment, animals were sacrificed 7 days after RD, and only cell counting of the ONL and TUNEL staining were performed. Both sets of results did not produce statistically significant changes with the use of LBP. Our preliminary data for the effect of LBP on retinal detachment shows no significant beneficial effect. / published_or_final_version / Medicine / Master / Master of Research in Medicine

The numerical simulation and modeling of plasma detachment from a magnetic nozzle is presented. The detachment problem is of key importance to the plasma-based propulsion concepts that employ a guiding magnetic field to control plasma flow and motivated by the needs of the VASIMR (Variable Specific Impulse Magnetoplasma Rocket) project. The detachment of the plasma exhaust is required to produce directed thrust. In the present scenario plasma can stretch the magnetic field lines to infinity, similar to the solar wind. In order to extend the magnetic nozzle model beyond the limitations of analytic theory, a numerical code is developed to simulate steady-state kinetic plasma flows and to evaluate nozzle efficiency. The direct solution of a steady-state problem, as opposed to an initial value problem, eliminates the need to deal with transient phenomena that are of secondary importance for continuously operated plasma thrusters. The new simulation code is verified against the analytic results and then used to model the plasma behaviour for the conditions of the Detachment Demonstration Experiment (DDEX) at the NASA Marshall Propulsion Research Center, Huntsville, Alabama. / text

Reconstructing the structural evolution of metamorphic core complexes is critical to understanding how large-magnitude extension is accommodated in the middle to upper crust. This dissertation focuses on the Miocene geometric and kinematic evolution of the Buckskin-Rawhide metamorphic core complex in west-central Arizona, addressing controversial topics including the geometric development of mid-crustal shear zones, the formation of detachment fault corrugations, and the transition from detachment faulting to more distributed deformation. Detailed microstructural data from mylonites in the lower plate of the Buckskin-Rawhide detachment fault indicate that early Miocene mylonitization was characterized by consistent top-NE-directed shear and ~450-500°C deformation temperatures that varied by [less-than or equal to]50°C across a distance of ~35 km in the extension direction. The relatively uniform deformation conditions and strain recorded in mylonitized ~22-21 Ma granitoids are incompatible with models in which the lower plate shear zone represents the down-dip continuation of a detachment fault. Instead, lower plate mylonites initiated as a subhorizontal shear zone that was captured and rapidly exhumed by a moderately to gently dipping detachment fault system. Structural data and geologic mapping demonstrate that the prominent NE-trending Buckskin-Rawhide detachment fault corrugations are folds produced by extension-perpendicular (NW-SE) shortening during core complex extension. Dominant NE-directed slip on the detachment fault was progressively overprinted by NW- and SE-directed slip associated with corrugation folding. Orientation patterns of upper plate bedding across the corrugations are compatible with folding about a NE-trending axis. Extension-perpendicular shortening in the lower plate is recorded by synmylonitic constriction and folding. Upright m-scale and km-scale lower plate folds parallel the detachment fault corrugations and developed primarily by postmylonitic flexural slip that was coeval with detachment faulting. The total amount of NW-SE shortening across the lower plate is ~10%, but the amount of NW-SE shortening recorded by the younger detachment fault is only ~1%. The relatively late-stage development of corrugations in the Buckskin-Rawhide metamorphic core complex suggests that extension-perpendicular shortening was primarily driven by a reduction of vertical stresses through crustal thinning and tectonic denudation. Brittle fault data document the transition from large-magnitude, NE-directed extension to distributed E-W extension and right-lateral faulting. Following exhumation to brittle conditions, lower plate mylonites were extended up to ~20-30% by NE-dipping, syndetachment normal faults. Towards the end of detachment faulting, the extension direction rotated clockwise, and some portions of the Buckskin detachment fault record a transition from dominant top-NE slip to ENE- and E-directed slip. After detachment faulting ceased, E-W extension was accommodated primarily by steeply NE-dipping, right-lateral and oblique right-lateral-normal faults. The cumulative amount of right-lateral shear across the core complex is probably 7-9 km, which is the amount needed to restore the topographic trend of lower plate corrugations into alignment with the dominant extension direction. Postdetachment right-lateral/transtensional faulting across the Buckskin-Rawhide metamorphic core complex reflects the increasing influence of the Pacific-North American transform plate boundary towards the end of the middle Miocene. / text

The attachment and detachment of circulating tumor cells in a functionalized microchannel under hydrodynamic loading have been studied. For the cell attachment experiments, EpCAM antibodies are immobilized on the microchannel surface to capture either PC3N prostate or MDA-MB-231 breast cancer cells from homogeneous cell suspensions. Using the same protocol, N-Cadherin antibodies are immoblilzed and used to study the detachment of target cancer cells captured in the microchannels.A critical flow rate Qc has been identified to characterize the kinetics of cell capture in a functionalized microchannel. Approaching one limit, when the receptor-ligand interaction dominates, more than 90% of moving cells can be captured and a sharp peak is observed in the spatial distribution of the captured cells. Approaching another limit, when hydrodynamic loading dominates, almost all cells cannot be captured in the channel. Between these two limits, there is a transition region in which both capture efficiency and cell distribution are sensitive to the flow parameters. Proper characteristic time and length scales have been identified to describe the cell spatial distribution using a log-normal statistical model. The kinetic details of cell capture are determined by the competition between the flow rate and the ligand-receptor association/dissociation rates.Additionally, the attachment dynamics of circulating tumor cells in a bio-functionalized microchannel under hydrodynamic loading has been explored. The target cells initially role along the microchannel with fluctuating velocity prior to firm adhesion. When a successful bond is established, the cancer cells require a certain length to come to a complete stop; this stopping length is found to depend linearly on the applied hydrodynamic flow rate. The force balance in the vertical cross stream direction is dominated by the gravitational force; as a result, all cells loaded into a microchannel intimately contact the functionalized channel bottom surface within a short time. The streamwise horizontal motion of the cells on the surface is dominated by the balance between the shear flow hydrodynamic loading and the receptor-ligand binding interaction. A linear spring element is incorporated in the physical model to represent the dynamics of a cancer cell captured by immobilized antibodies. Featuring a mobility matrix, a proposed theoretical model is utilized to estimate the binding and hydrodynamic forces acting on the cell in a microchannel. Inserting certain fitting parameters, the time evolution of a stopping cell is successfully predicted by a simplified exponential function.The mechanical response of a captured cancer cell to a hydrodynamic flow field is investigated and, in particular, the effect of flow acceleration is examined. The observed cell deformation is dramatic under low acceleration, but is negligible under high acceleration. Consequently, the detachment of captured cells depends on both flow rate and flow acceleration. The flow rate required for cell detachment is a random variable that can be described by a log-normal distribution. Two flow acceleration limits have been identified for proper scaling of the flow rate required to detach captured cells. A time constant on the order of 1min for the mechanical response of a captured cell has been identified for scaling the flow acceleration. Based on these acceleration limits and the time constant, an exponential-like empirical model is proposed to predict the flow rate required for cell detachment as a function of flow acceleration.

Thesis (M.A.)--Northern Kentucky University, 2008. / Made available through ProQuest. Publication number: AAT 1450346. ProQuest document ID: 1490080981. Includes bibliographical references (p. 36-40)

The Heart Mountain Detachment (HMD) in Wyoming constitutes one of the largest known rock slides (3400 km2) on Earth. This detachment took place along the stratigraphic boundary between the Bighorn Dolomite at the hanging-wall and the Snowy Range Formation at the footwall. The slide resulted in the formation of an up to 3 m-thick carbonate ultracataclasite (CUC) at the base of the slide. The origin of the CUC and the nature of the triggering mechanism responsible for the initiation of the catastrophic movement have long been controversial. The most widely accepted theory is a mid-Eocene eruption in the Absaroka volcanic province that triggered rupture and subsequent detachment of Paleozoic rocks. Rapid sliding was facilitated by basal fluidization generated by thermo-mechanical decomposition of carbonate rocks. Here I present a proof of concept study addressing the question of the consistent magnetic fabrics observed in the CUC, as well as new observations indicating the discovery of mineral grains of volcanic origin within the CUC. Additionally, some constraints are placed on the thermo-chemical conditions operating at the base of this catastrophic landslide. Overall, the CUC displays an average magnetic susceptibility one order of magnitude higher (1803 . -6 [SI]) than the overlying Bighorn Dolomite (148 . -6 [SI]) and underlying Snowy Range Fm (636 . -6 [SI]). Anisotropy of magnetic susceptibility (AMS) data, field observations and microstructural analysis suggest that ferromagnetic (s.l) minerals in the CUC originate from the Bighorn Dolomite, the Tertiary volcanics and synkinematic thermal decomposition of pyrite into pyrrhotite and magnetite. Thermomagnetic investigations revealed a Curie temperature of 525 °C which suggests that magnetite is the dominant magnetic carrier mineral in the CUC. Energy Dispersive Spectroscopy analyses confirm that this magnetite has a relatively low ulvöspinel content. Magnetic hysteresis properties point to an average pseudo-single domain magnetic grain size or, alternatively, a mixture of single domain and multi-domain grains. The origin of AMS is magnetostatic, elucidated by a high degree of consistency between AMS directions and 3–D SPO directions. The anisotropy of magnetic susceptibility (AMS) directional data displays two dominant fabric orientations suggesting possible strain partitioning in the CUC. The consistency of magnetic fabrics suggests that the CUC followed a dominantly transpressive regime. The deformation mechanism causing the consistent AMS is a homogeneous passive rotation of magnetite grains. Microstructural analysis of iron bearing minerals suggests that a high oxygen fugacity was present in the CUC at the onset of the slide. Evidence for elevated temperatures in the CUC is shown by broken twins in calcite which form as result of dynamic recrystallization. High pore fluid in the CUC is indicated by CUC dikes intruding the hanging wall and by accretionary grains (lapilli). Finally, the presence of unserpentinized and a few weakly serpentinized olivine clasts in the CUC brings the "hot water" weakening mechanism proposed by Ahranov and Anders (2006) into question.

La dépersonnalisation, un trouble au coeur de l'être. Le sujet atteint par cette pathologie a la sensation que la vie est unrêve ou une illusion tout en ayant conscience d'un temps où il lui semblait qu'il était plus ancré dans la réalité. Son rapport au corps est extrêmement modifié et celui à l'environnement aussi (déréalisation). Cette perte de sens peut conduire à la dépression et à une apathie générale. Le sujet ne se sentant plus arrimé à la réalité a tendance à se replier sur lui-même. A l'heure actuelle il n'y a pas d'accord sur la symptomatologie de la dépersonnalisation et elle contient assez de tableaux différents, selon les auteurs, pour permettre l'élaboration des théories les plus diverses. Symptôme, syndrome ou mécanisme de défense, nous retrouvons la dépersonnalisation à l'occasion de multiples pathologies et elle est observable dans toutes les structures. Consécutive à la forclusion du Nom-du-Père ou encore conséquence d'un traumatisme, son caractère transnosographique laisse à penser qu'elle est étroitement liée à la structure même du sujet. De l'Unheimlich de Freud à l'Extime de Lacan, la dépersonnalisation vient souligner la question de l'identité et pointe sa nature structurale. / Depersonalization is a disorder within the self. Subjects suffering from this disorder feel that life is a dream or an illusion, whilst being aware of a time when they felt they were more grounded in reality. Their bodily sensations and perception of the outside world are severely altered (derealization). This loss of sense can cause depression and general apathy. As the subject no longer feels grounded in reality, they tend to become withdrawn. There is currently no agreement as to the symptoms of depersonalization, for which different authors have quite different tables, allowing extremely diverse theories to be put forward. Depersonalization is variously described as a symptom, a syndrome, or a defence mechanism in a large number of disorders, and it can be observed in all structures. Following foreclosure of the Name-of-the-Father or as a result of trauma, its transnosographic dimension suggests that it is closely linked to the structure of the subject itself. From the “uncanny” (unheimlich) described by Freud to Lacan’s “extimacy”, depersonalization emphasises the issue of identity and highlights its structural nature.

Partindo da conexão entre comunicação e cultura, este estudo tem como objetivo contribuir para um melhor entendimento acerca das intervenções culturais contrahegemônicas, que tem na Companhia do Latão uma importante referência atual. Com essa proposta, faz-se uso de algumas das proposições metodológicas indicadas por Karl Marx, segundo as quais a apreensão do mundo real não se dá a partir de um método determinado a priori, mas sim que este deve ser deduzido do próprio objeto de estudo. Portanto, o passo inicial e determinante para todo o trajeto é a análise imanente, isto é, o exame crítico do objeto de pesquisa como fonte primeira e da qual deve retirar-se o máximo possível de determinações, bem como os caminhos para pesquisá-lo. Estipulou-se para início da pesquisa a década de 1960, momento que deixou marcas profundas na vida cultural, política, social e econômica de nosso país, podendo ser lido como um ponto chave para a compreensão da história nacional, bem como das diversas tentativas feitas pelos agentes culturais no sentido de buscar um novo tipo de relacionamento com o público receptor. É também nesta década que aparecem, em sua melhor forma, os grupos de teatro de pesquisa, tradição da qual a Companhia do Latão faz parte. Interessa-nos entender quais foram as verdadeiras mudanças, em termos de experiência cultural e política, causadas pelo Golpe de 1964 e o que foi fomentado mesmo sob a repressão do AI-5, bem como as suas consequências nas décadas que o seguiram, principalmente, na arte engajada e de intervenção política. / Based on the connection between communication and culture this study aims to contribute for a better understanding of counter-hegemonic cultural interventions, which has in Companhia do Latão an important reference nowadays. With this proposal, we use some methodological approaches indicated by Karl Marx, which claims that the seizure of the real world is not derived from a method determined in advance, but this goal must be deducted from the object of study itself. Therefore, the initial and determining step for the entire trajectory analysis is immanent, that is, the critical examination of the research object as primary source and of which we should withdraw, as much as possible, the determinations, as well as the ways to research it. The 1960s was stipulated as the starting point of this research, moment that left a deep mark on the cultural, political and economic structure of our country, and can be read as a key point to understand the national history, as well as several attempts made by cultural agents in order to seek a new kind of relationship with the receiver public. Also, in this decade, appears, in its better form, the theater groups of research, a tradition in which Companhia do Latão shares. We want to understand what were the real changes in terms of cultural and political experience caused by the Coup of 1964, and what was promoted even under the AI-5 repression, as well as its consequences in the following decades, mainly in the activist and political intervention art.

Orientadores: Rodrigo Pessoa Cavalcanti Lira, Carlos Eduardo Leite Arieta / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-20T06:50:41Z (GMT). No. of bitstreams: 1 Takasaka_Iuuki_M.pdf: 2254339 bytes, checksum: 4a21730e60893b2777df71653d5f38c2 (MD5) Previous issue date: 2012 / Resumo: Introdução: O descolamento de retina regmatogênico (DRR), uma das causas de cegueira, tem uma incidência anual de cerca de 6,3 - 17,9/100.000 habitantes na população mundial, e se não tratado pode levar a cegueira devido a degeneração das camadas retinianas. O uso de introflexão em conjunto com as adesões coriorretinianas em torno da rotura retiniana forma a base do tratamento para muitos DRR simples. A crioterapia realizada para retinopexia intra-operatoria tem sido implicada no desenvolvimento de pucker macular e vitreorretinopatia proliferativa. Eliminar a crioterapia da cirurgia convencional de introflexão poderia não afetar o resultado do sucesso anatômico e melhorar a recuperação visual. Objetivo: O objetivo primário deste ensaio clínico randomizado foi comparar a taxa de reaplicação retiniana e secundariamente os resultados da acuidade visual em pacientes com DRR que se submeteram a cirurgia de introflexão escleral e retinopexia com a crioterapia intra-operatória versus fotocoagulação a laser pós-operatório (um mês após a cirurgia). Método: É um ensaio clínico aleatorizado, mascarado, realizado em um único centro, composto por 86 pacientes submetidos à cirurgia de introflexão escleral. Os pacientes foram aleatorizados para serem submetidos à cirurgia de introflexão escleral e retinopexia com crioterapia intraoperatória (criopexia) ou retinopexia com fotocoagulação a laser pós operatória de 30 dias (laserpexia) após o procedimento. O desfecho primário foi avaliar a taxa de reaplicação retiniana no seguimento pós-operatório em 1 semana. Os desfechos secundários foram avaliar as taxas de reaplicação retiniana, as taxas de reoperação, as taxas de complicações pós-operatórias e recuperação da acuidade visual, em 1 mês e 6 meses de seguimento pós-operatório. Resultados: Foram incluídos 86 olhos de 86 pacientes a serem submetidos introflexão escleral. A amostra foi constituída de 43 pacientes pertencentes ao grupo laserpexia e 43 pacientes atribuídos ao grupo criopexia. Os dados demográficos foram semelhantes nos dois grupos. A taxa de sucesso anatômico em 1 semana, 1 mês e 6 meses foram semelhantes nos dois grupos, respectivamente, 93% (40 pacientes), 100% e 100% no grupo criopexia e 95,3% (41 pacientes), 100% e 100% no grupo da laserpexia (P, respectivamente, 0,5; 1,0 e 1,0). Três pacientes do grupo criopexia e 2 do laserpexia foram submetidos a uma cirurgia adicional (vitrectomia via pars plana) após a falha primária em 1 semana de seguimento. As complicações pós-operatórias foram semelhantes nos dois grupos, com exceção do edema de pálpebras. A recuperação visual foi mais lenta no grupo da crioterapia. A diferença na AV após 6 meses não foi significativa. Conclusão: Em pacientes com descolamento de retina regmatogênico sem complicações, ambas as técnicas de retinopexia mostraram resultados anatômico e funcional satisfatórios. A opção por laserpexia oferece recuperação visual mais rápida com menos complicações, porém requer uma segunda intervenção e maior custo em relação a criopexia / Abstract: Introduction: Rhegmatogenous retinal detachment (RRD), one of causes of blindness, has an annual incidence of about 6.3 to 17.9/100.000 people in the world population, and if untreated can lead to blindness due to degeneration of the retinal layers. The use of scleral buckles combined with chorioretinal adhesions around the retinal tear forms the basis of treatment for many simple RRD. Cryotherapy for retinopexy performed intraoperatively has been implicated in the development of macular pucker and proliferative vitreoretinopathy. Eliminating cryotherapy of conventional surgery might not affect the outcome of anatomic success and improve visual recovery. Objective: The aim of this randomized clinical trial was to compare the rate of retinal reapplication and secondly the results of visual acuity in patients with rhegmatogenuos retinal detachment who underwent surgery with scleral buckle retinopexy and intraoperative cryotherapy versus laser photocoagulation postoperatively (one month after surgery). Method: A randomized, masked, performed in a single center, comprising 86 patients undergoing scleral buckle surgery. Patients were randomized to undergo surgery, scleral buckle retinopexy with cryotherapy and intraoperative (criopexy) or postoperative retinopexy with photocoagulation 30 days (laserpexy) after the procedure. The primary endpoint was to evaluate the rate of replication in retinal postoperative follow-up within 1 week. Secondary endpoints were to evaluate retinal reapplication rates, reoperation rates, rates of postoperative complications and recovery of visual acuity at 1 month and 6 months postoperative follow-up. Results: We included 86 eyes of 86 patients undergoing scleral buckle. The sample consisted of 43 patients belonging to the group laserpexy and 43 patients assigned to the group criopexy. Demographic data were similar in both groups. The anatomic success rate in 1 week, 1 month and 6 months were similar in both groups, respectively, 93% (40 patients), 100% and 100% in criopexy and 95.3% (41 patients), and 100% 100% in group laserpexy (P, respectively, 0.5, 1.0 and 1.0). Three patients of group criopexy and 2 of laserpexy underwent additional surgery (pars plana vitrectomy) after the primary failure at 1-week follow-up. The postoperative complications were similar in both groups, except for edema of the eyelids. The visual recovery was slower in the cryotherapy group. The difference in VA after 6 months was not significant. Conclusion: In patients with uncomplicated rhegmatogenuos retinal detachment, both techniques of retinopexy showed satisfactory anatomical and functional results. The choice of laserpexy offers faster visual recovery with fewer complications, but requires a second intervention and higher cost compared to criopexy / Mestrado / Oftalmologia / Mestre em Ciências Médicas