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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.
91

Ninho, casa e corpo / Ninho, casa e corpo

Bortolin, Rosana Tagliari 07 March 2006 (has links)
Esta dissertação relata e traduz o percurso de estudos, reflexões, pesquisas e procedimentos, dedicados à elaboração de um conjunto de trabalhos realizados com a terra, com a cerâmica, sobre a temática dos ninhos e casulos a partir das vivências que meu corpo atual e consciente, tem com a natureza que me cerca. As reflexões desencadeadas por essas vivências fazem uma relação análoga dos ninhos e casulos com a casa e com o corpo enquanto ninho primordial. / This paper reports and translates the way studies, reflections, researches and procedures, dedicated to a work set elaboration that was done with earth, about the nestles thematic, started to the experiences that my conscious body has with that nature that surround me. The reflections unchained by those experiences do a nestles analog relation with the house and the body as a prime nestle.
92

Bounds on RF cooperative localization for video capsule endoscopy

Ye, Yunxing 29 April 2013 (has links)
Wireless video capsule endoscopy has been in use for over a decade and it uses radio frequency (RF) signals to transmit approximately fifty five thousands clear pictures of inside the GI tract to the body-mounted sensor array. However, physician has no clue on the exact location of the capsule inside the GI tract to associate it with the pictures showing abnormalities such as bleeding or tumors. It is desirable to use the same RF signal for localization of the VCE as it passes through the human GI tract. In this thesis, we address the accuracy limits of RF localization techniques for VCE localization applications. We present an assessment of the accuracy of cooperative localization of VCE using radio frequency (RF) signals with particular emphasis on localization inside the small intestine. We derive the Cramer-Rao Lower Bound (CRLB) for cooperative location estimators using the received signal strength(RSS) or the time of arrival (TOA) of the RF signal. Our derivations are based on a three-dimension human body model, an existing model for RSS propagation from implant organs to body surface and a TOA ranging error model for the effects of non-homogenity of the human body on TOA of the RF signals. Using models for RSS and TOA errors, we first calculate the 3D CRLB bounds for cooperative localization of the VCE in three major digestive organs in the path of GI tract: the stomach, the small intestine and the large intestine. Then we analyze the performance of localization techniques on a typical path inside the small intestine. Our analysis includes the effects of number of external sensors, the external sensor array topology, number of VCE in cooperation and the random variations in transmit power from the capsule.
93

A Testbed for Design and Performance Evaluation of Visual Localization Technique inside the Small Intestine

Mi, Liang 01 May 2014 (has links)
Wireless video capsule endoscopy (VCE) plays an increasingly important role in assisting clinical diagnoses of gastrointestinal (GI) diseases. It provides a non-invasive way to examine the entire small intestine, where other conventional endoscopic instruments can barely reach. Existing examination systems for the VCE cannot track the location of a endoscopic capsule, which prevents the physician from identifying the exact location of the diseases. During the eight hour examination time, the video capsule continuously keeps taking images at a frame rate up to six frame per sec, so it is possible to extract the motion information from the content of the image sequence. Many attempts have been made to develop computer vision algorithms to detect the motion of the capsule based on the small changes in the consecutive video frames and then trace the location of the capsule. However, validation of those algorithms has become a challenging topic because conducting experiments on the human body is extremely difficult due to individual differences and legal issues. In this thesis, two validation approaches for motion tracking of the VCE are presented in detail respectively. One approach is to build a physical testbed with a plastic pipe and an endoscopy camera; the other is to build a virtual testbed by creating a three-dimensional virtual small intestine model and simulating the motion of the capsule. Based on the virtual testbed, a physiological factor, intestinal contraction, has been studied in terms of its influence on visual based localization algorithm and a geometric model for measuring the amount of contraction is proposed and validated via the virtual testbed. Empirical results have made contributions in support of the performance evaluation of other research on the visual based localization algorithm of VCE.
94

Morfologia de folículos ovarianos de zebrafish após criopreservação utilizando uma cápsula de metal / Morphology of zebrafish ovarian follicles after cryopreservation using a metal capsule

Gomes, Itamar Cossina January 2016 (has links)
O apelo pela conservação ambiental e o significativo aumento no número de organismos cultivados de alto valor genético demandam tecnologias que permitam conservar sua genética, mesmo após a morte do animal. A criopreservação de gametas possibilita a preservação da genética de espécies ameaçadas e de interesse comercial, prolongando sua vida reprodutiva evitando assim a perda de material genético por doenças, catástrofes, transferência de animais ou perda do habitat natural. A criopreservação tem sido aplicada à conservação de ovários e tecido ovariano, no entanto, há muitas controvérsias acerca de qual seria o melhor protocolo a ser utilizado. Tendo isso em vista, o presente estudo teve como objetivo avaliar a morfologia do tecido ovariano de zebrafish criopreservado em cápsula de metal com o uso de diferentes soluções crioprotetoras. As soluções crioprotetoras utilizadas foram: 1,5 M metanol + 4,5 M propileno glicol (SC1); 1,5 M metanol + 5,5 M Me2SO (SC2); 1,5 M metanol + 4,5 M propileno glicol + 0,5 M sacarose (SC3); 1,5 M metanol + 5,5 M Me2SO + 0,5 M sacarose (SC4). Após o descongelamento a integridade de cinco estágios de desenvolvimento folicular foi avaliada em cada grupo. A morfologia celular foi observada através de análise histológica. A análise dos dados mostrou que os folículos em estágio I e II foram os melhores criopreservados em todos os grupos experimentais. Sendo que, os grupos SC4 e SC2 foram os que apresentaram os melhores resultados, respectivamente com 88,26% e 84,2% de folículos sem alterações morfológicas. Já os estágios foliculares mais avançados de desenvolvimento (estágios IV e V) apresentaram-se com alterações em todos os grupos. Portanto, apesar do sucesso na criopreservação dos estágios foliculares mais iniciais (I e II) foi possível identificar alterações morfológicas em todos os grupos avaliados. Dentre as principais alterações identificadas estão a aglutinação do citoplasma e enrugamento e ruptura da membrana do envelope celular. Ao avaliar os resultados pode-se concluir que apesar do uso da capsula de metal em associação com as soluções SC4 e SC2 apresentarem os melhores resultados, as soluções SC1 e SC3 também foram eficientes na manutenção da integridade morfológica de folículos imaturos, e portanto essa metodologia pode ser utilizada com sucesso na criopreservação de folículos imaturos. / The appeal for environmental conservation and the significant increase in the number of farmed organisms with high genetic value demand technologies to allow preserving their genetics, even after the death. Cryopreservation of gametes allows the preservation of genetics of the endangered and commercial species, prolonging their reproductive life. Furthermore, this technology prevents the loss of genetic material caused by diseases, disasters, transfer of animals or loss of natural habitat. Cryopreservation has been applied to the conservation of ovaries and ovarian tissue, however, there are many controversies regarding what would be the best protocol to use. Thus, the aim of this study was to evaluate the morphology of cryopreserved zebrafish ovarian tissue using a metal capsule with four different cryoprotectant solutions. The cryoprotectant solutions used were: 1.5M methanol + 4.5 M propylene glycol (CS1); 1.5M methanol + 5.5 M Me2SO (CS2); 1.5M methanol + 4.5 M propylene glycol + 0.5 M sucrose (CS3); Methanol + 1.5 M 5.5 M 0.5 M sucrose + Me2SO (CS4). After heating the integrity of the five stages of follicular development was assessed in each group. Cell morphology was observed by histological analysis. The thermal gradient inside the capsule and the sample was verified by a thermistor Pt500, model Keithley 2001A. The data analysis shows that the follicles at stage I and II were better cryopreserved among all experimental groups. The treatments CS4 and CS2 showed the best results, respectively with 88.26% and 84.2% of follicles without morphological changes in stage I. The most advanced follicular development stages (stages IV and V) showed changes in all treatments. Therefore, despite the successful cryopreservation of earlier follicular stages (I and II), it was possible to identify morphological changes in all the groups. Among the main changes identified, agglutination of cytoplasm and rupture of cell and wrinkling of the egg envelope could be observed. Despite the use of the metal capsule in association with the CS4 and CS2 solutions showed the best results, CS1 and CS3 solutions were also effective in maintaining the morphological integrity of immature follicles, therefore this method can be successfully used in the cryopreservation of immature follicles.
95

Padronização da técnica de imuno-histoquímica e investigação de componentes desencadeadores da contratura articular em ovinos

SANTOS, Jomel Francisco dos 03 June 2013 (has links)
Submitted by (lucia.rodrigues@ufrpe.br) on 2017-02-09T14:23:37Z No. of bitstreams: 1 Jomel Francisco dos Santos.pdf: 1033055 bytes, checksum: 0882131c9f37caac6cc396d21eb8c175 (MD5) / Made available in DSpace on 2017-02-09T14:23:37Z (GMT). No. of bitstreams: 1 Jomel Francisco dos Santos.pdf: 1033055 bytes, checksum: 0882131c9f37caac6cc396d21eb8c175 (MD5) Previous issue date: 2013-06-03 / Joint contractures are a severe complication of joint injuries that can permanently limit the extremity function. Current treatments for contractures in humans have little effect and there is an obvious need for clarification of the pathophysiology of this chronic and disabling dysfunction. Sheep joint is a promising model for the investigation of normal and pathologic states by the similarity with the biomechanics of certain human joints. The aim of this study was to investigate by the techniques of immunohistochemistry and cytochemistry the presence of key components for the development of joint contractures in sheep and to evaluate the potential of this species as an experimental model to study this disease. Therefore, we used 15 knee joint capsules of healthy Santa Inês ewes to identify myofibroblasts and mast cells. For investigation of myofibroblasts was performed immunohistochemical technique. Following histologic routine preparation, the antigen retrieval was performed by heating in citrate, followed by peroxidases blockage, blocking nonspecific protein and then primary antibody was incubated. After the secondary antibody was added to the cuts, and DAB chromogen was added. Slides were counterstained with Harris Hematoxylin and mounted. In cytochemical technique was applied the stain Toluidine Blue to disclosure mast cells. Analysis of the cuts was made under a light microscope. Positive controls of myofibroblasts (ovine cervix) and mast cells (umbilical cord) were stained satisfactorily by the standard techniques. In joint capsules, α-SMA protein was observed in the wall of arteries and rare myofibroblasts were observed in each section, as well as few mast cells were scored. Other studies about ovine joint capsule injuries must be conducted to confirm the presence of myofibroblasts and the development of joint contracture. / As contraturas articulares são complicações severas de doenças articulares que podem limitar permanentemente a função de extremidades. Os tratamentos atuais para contratura em seres humanos têm pouca eficácia e há uma evidente necessidade de esclarecimento sobre a patofisiologia dessa disfunção crônica e incapacitante. A articulação do ovino é um modelo promissor para a investigação dos estados normais e patológicos, pela semelhança com a biomecânica de determinadas articulações humanas. O objetivo deste trabalho foi investigar por meio das técnicas de imuno-histoquímica e citoquímica a presença de componentes-chave para o desenvolvimento da contratura articular na espécie ovina e avaliar a potencialidade desta espécie como modelo experimental para estudo desta patologia. Para tanto, foram utilizadas 15 cápsulas articulares de joelhos de ovelhas Santa Inês sadias para localização de miofibroblastos e mastócitos. Para investigação de miofibroblastos foi realizada a técnica de imuno-histoquímica. Após a preparação para rotina histológica, a recuperação antigênica foi realizada por aquecimento em citrato, seguida pelo bloqueio das peroxidades, bloqueio de proteínas inespecíficas e então, o anticorpo primário foi incubado. Após, o anticorpo secundário foi acrescentado aos cortes, e o cromógeno DAB foi adicionado. As lâminas foram contracoradas com Hematoxilina de Harris e montadas. Na técnica citoquímica, foi aplicada a coloração de Azul de Toluidina para evidenciação dos mastócitos. As análises dos cortes foram feitas em microscópio de luz. Os controles positivos da pesquisa de α-SMA (cérvix ovina) e de mastócitos (cordão umbilical) foram marcados ou corados satisfatoriamente pelas respectivas técnicas. Nas cápsulas articulares, a proteína foi observada na parede de artérias e raros miofibroblastos foram observados em cada corte, assim como poucos mastócitos foram corados. Outros estudos sobre lesões de cápsula articular de ovinos devem ser conduzidos para confirmar a presença de miofibroblastos e o desenvolvimento da contratura articular.
96

Thermal Assessment of a Latent-Heat Energy Storage Module During Melting and Freezing for Solar Energy Applications

Ramos Archibold, Antonio Miguel 06 November 2014 (has links)
Capital investment reduction, exergetic efficiency improvement and material compatibility issues have been identified as the primary techno-economic challenges associated, with the near-term development and deployment of thermal energy storage (TES) in commercial-scale concentrating solar power plants. Three TES techniques have gained attention in the solar energy research community as possible candidates to reduce the cost of solar-generated electricity, namely (1) sensible heat storage, (2) latent heat (tank filled with phase change materials (PCMs) or encapsulated PCMs packed in a vessel) and (3) thermochemical storage. Among these the PCM macro-encapsulation approach seems to be one of the most-promising methods because of its potential to develop more effective energy exchange, reduce the cost associated with the tank and increase the exergetic efficiency. However, the technological barriers to this approach arise from the encapsulation techniques used to create a durable capsule, as well as an assessment of the fundamental thermal energy transport mechanisms during the phase change. A comprehensive study of the energy exchange interactions and induced fluid flow during melting and solidification of a confined storage medium is reported in this investigation from a theoretical perspective. Emphasis has been placed on the thermal characterization of a single constituent storage module rather than an entire storage system, in order to, precisely capture the energy exchange contributions of all the fundamental heat transfer mechanisms during the phase change processes. Two-dimensional, axisymmetric, transient equations for mass, momentum and energy conservation have been solved numerically by the finite volume scheme. Initially, the interaction between conduction and natural convection energy transport modes, in the absence of thermal radiation, is investigated for solar power applications at temperatures (300 - 400°). Later, participating thermal radiation within the storage medium has been included in order to extend the conventional natural convection-dominated model and to analyze its influence on the melting and freezing dynamics at elevated temperatures (800 - 850°). A parametric analysis has been performed in order to ascertain the effects of the controlling parameters on the melting/freezing rates and the total and radiative heat transfer rates at the inner surface of the shell. The results show that the presence of thermal radiation enhances the melting and solidification processes. Finally, a simplified model of the packed bed heat exchanger with multiple spherical capsules filled with the storage medium and positioned in a vertical array inside a cylindrical container is analyzed and numerically solved. The influence of the inlet mass flow rate, inner shell surface emissivity and PCM attenuation coefficient on the melting dynamics of the PCM has been analyzed and quantified.
97

Enabling active locomotion and advanced features in capsule endoscopy

Alonso Casanovas, Oscar 27 April 2012 (has links)
The significant development in medical diagnostics and imaging has brought up a lot of new wireless capsule endoscopes coming to health care market. The capsule has been able to minimize patient discomfort and pain during digestive tract screening with less risk of infection and harmless to body organs. This kind of medical procedure is less invasive and gives a great impact compared to the traditional method. Although pill-shaped capsules have existed for over 11 years by now and are currently being used successfully in medical screening to study the GI tract, these systems are passive and are dependent to the peristaltic movement of the gastric wall to propel. The aim of this work is to provide the electronics needed to control an endoscopic capsule robot and the electronics needed to enable active locomotion and advanced vision functions (like autofocus). Enabling such functions the capsules will be able to perform screening, diagnosis and therapy. Such capsule robot has been designed in the framework of the “Versatile Endoscopic Capsule for Gastrointestinal Tumour Recognition and Therapy” (VECTOR) project. This project pursues the goal of realizing smart pill technologies and applications for gastrointestinal (GI) diagnosis and therapy. The overall medical goal of the project is to enable medical devices through advanced technology that can dramatically improve early detection and treatment of GI early cancers and cancer precursors. The main technological objective of the project is the take-up of microsystems and sub-components and their integration into robotic, mobile pill devices for useful and large impact applications in the medical field.
98

The Regulation of Salmonella Typhi Vi Capsular Antigen Expression in Intestinal Model Epithelia and the Bovine Ligated-Ileal Loop Model

Tran, Quynh Tien-Ngoc 2009 August 1900 (has links)
Salmonella enterica serovar Typhi, a major public health concern in developing countries, continues to be a priority for the World Health Organization. S. Typhi possesses a viaB locus responsible for the biosynthesis of the Vi-capsular antigen, a significant virulence factor at the focus of developing improved prophylaxis for typhoid fever. Tissue culture experiments have demonstrated that S. Typhi wild-type capsule-expressing strain elicits less chemokine secretion than a viaB mutant. Calf experiments using the viaB mutant resulted in an increase inflammatory response. Osmolarity is one of the control signals that affect the biosynthesis of the Vi antigen. Under high osmolarity growth conditions of 300 mM and greater, Vi production is suppressed and S. Typhi is highly invasive. Studies reveal that the viaB mutant displays increased invasion towards intestinal epithelial cells. Our first objective was to implement direct and indirect methods to localize and detect Vi expression within intestinal epithelial cells and bovine Peyer's patch. The second objective was to compare the invasiveness between a viaB mutant, an ompR mutant, and S. Typhi grown under hyperosmolarity. We also measured the effects of these strains in eliciting inflammation in the calf model. We report that tviB was significantly up regulated intracellularly within T84 polarized cells. In the calf experiments, tviB was expressed at levels significantly higher in calf tissue following invasion compared to inoculum grown under Vi-suppressing conditions. Together, these results support the idea that the Vi capsular antigen is expressed after invasion of intestinal epithelial cells in vivo. We found that S. Typhi grown under high osmolarity, the viaB mutant, and the ompR mutant had increased invasion in polarized T84 cells and bovine ileal tissue. Fluid accumulation among Vi-deficient and Vi-suppressed strains was similar. The histopathology of the inflammatory lesions of the small intestine produced by the Vi-deficient and suppressed strains was quite comparable. Our data supports the notion that Vi-suppressed and Vi mutants of S. Typhi exhibit similar levels of increased invasion and inflammation, perhaps mechanistically through the inactivation of the Vi antigen.
99

Experimental Investigation of Encapsulated Phase Change Materials for Thermal Energy Storage

Alam, Tanvir E 01 January 2015 (has links)
Thermal energy storage (TES) is one of the most attractive and cost effective solutions to the intermittent generation systems like solar, wind and other renewable sources, compared to alternatives. It creates a bridge between the power supply and demand during peak hours or at times of emergency to ensure the continuous supply of energy. Among all the TES systems, latent heat thermal energy storage (LHTES) draws lots of interests as it has high energy density and can store or retrieve energy isothermally. Two major technical challenges associated with the LHTES are low thermal conductivity of the phase change materials (PCMs), and corrosion tendency of the containment vessel with the PCMs. Macro-encapsulation of the PCM is one of the techniques to encounter the low thermal conductivity issue as it will maximize the heat transfer area for the given volume of the PCM and restrict the PCMs to get in contact with the containment vessel. However, finding a suitable encapsulation technique that can address the volumetric expansion problem and compatible shell material are significant barriers of this approach. In the present work, an innovative technique to encapsulate PCMs that melt in the 100-350 oC temperature range was developed for industrial and private applications. This technique did not require a sacrificial layer to accommodate the volumetric expansion of the PCMs on melting. The encapsulation consisted of coating a non-reactive polymer over the PCM pellet followed by deposition of a metal layer by a novel non-vacuum metal deposition technique. The fabricated spherical capsules were tested in different heat transfer fluid (HTF) environments like air, oil and molten salt (solar salt). Thermophysical properties of the PCMs were investigated by DSC/TGA, IR and weight change analysis before and after the thermal cycling. Also, the constrained melting and solidification of sodium nitrate PCM inside the spherical capsules of different sizes were compared to explore the charging and discharging time. To accomplish this, three thermocouples were installed vertically inside the capsule at three equidistant positions. Low-density graphene was dispersed in the PCM to increase its conductivity and compared with pure PCM capsules. A laboratory scale packed-bed LHTES system was designed and built to investigate the performance of the capsules. Sodium nitrate (m.p. 306oC) was used as the PCM and air was used as the heat transfer fluid (HTF). The storage system was operated between 286oC and 326oC and the volumetric flow rate of the HTF was varied from 110 m3/h to 151 m3/h. The temperature distribution along the bed (radially and axially) and inside the capsules was monitored continuously during charging and discharging of the system. The effect of the HTF mass flow rate on the charging and discharging time and on the pressure drop across the bed was evaluated. Also, the energy and exergy efficiencies were calculated for three different flow rates. Finally, a step-by-step trial manufacturing process was proposed to produce large number of spherical capsules.
100

Quantitative measurements of ablation-products transport in supersonic turbulent flows using planar laser-induced fluorescence

Combs, Christopher Stanley 17 September 2015 (has links)
A recently-developed experimental technique based on the sublimation of naphthalene, which enables imaging of the dispersion of a passive scalar using planar laser-induced fluorescence (PLIF), is applied to a Mach 5 turbulent boundary layer and a NASA Orion capsule flowfield. To enable the quantification of naphthalene PLIF images, quantitative fluorescence and quenching measurements were made in a temperature- and pressure-regulated test cell. The test cell measurements were of the naphthalene fluorescence lifetime and integrated fluorescence signal over the temperature range of 100 K to 525 K and pressure range of 1 kPa to 40 kPa in air. These data enabled the calculation of naphthalene fluorescence yield and absorption cross section over the range of temperatures and pressures tested, which were then fit to simple functional forms for use in the calibration of the PLIF images. Quantitative naphthalene PLIF images in the Mach 5 boundary layer revealed large-scale naphthalene vapor structures that were regularly ejected out to wall distances of approximately y/δ = 0.6 for a field of view that spanned 3δ to 5δ downstream of the trailing edge of the naphthalene insert. The magnitude of the calculated naphthalene mole fraction in these structures at y/δ = 0.2 ranged from approximately 1-6% of the saturation mole fraction at the wind tunnel recovery temperature and static pressure. An uncertainty analysis showed that the uncertainty in the inferred naphthalene mole fraction measurements was ± 20%. Mean mole fraction profiles collected at different streamwise locations were normalized by the mole fraction measured at the wall and a characteristic height of the scalar boundary layer, causing the profiles to collapse into one “universal” mole fraction profile. Two-dimensional fields of naphthalene mole fraction were also obtained simultaneously with velocity by using particle image velocimetry (PIV) and PLIF. The images show large-scale naphthalene vapor structures that coincide with regions of relatively low streamwise velocity. The covariance of naphthalene mole fraction with velocity indicates that an ejection mechanism is transporting low-momentum, high-scalar-concentration fluid away from the wall, resulting in the protrusions of naphthalene vapor evident in the instantaneous PLIF images. Lastly, naphthalene PLIF was used to visualize the dispersion of gas-phase ablation products on a scaled Orion capsule model at four different angles of attack at Mach 5. High concentrations of scalar were imaged in the capsule recirculation region. Additionally, intermittent turbulent structures were visualized on the heat shield surface, particularly for the 12° and 52° AoA cases.

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