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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.
41

Perfil de citocinas séricas e termografia em equinos quarto de milha submetidos à prova de laço em dupla /

Gerardi, Bianca. January 2016 (has links)
Orientador: Luiz Claudio Nogueira Mendes / Banca: Flávia de Almeida Lucas / Banca:Lina Maria Wehrle Gomide / Banca:Fernanda Bovino / Banca:João Pessoa Araújo Junior / Resumo: Os objetivos do presente estudo foram verificar se existe reação inflamatória no exercício de curta duração e alta intensidade e se a mesma pode ser classificada em Th1, Th2 ou Th17. Além disso, verificar se as temperaturas corpóreas e locais se alteram com exercício este e se treinamentos distintos podem influenciar nestas alterações. Utilizaram-se 12 animais, idade entre 3 e 6 anos e peso médio de 450 kg, participantes de laço em dupla, divididos em: treino regular (GTR) e treino esporádico (GTE). O sangue coletado em tubos de 10 ml sem anticoagulante. Coletas e aferições de temperatura foram realizadas 30 minutos antes, imediatamente depois, uma, duas, seis, e 24 horas após o exercício. Utilizou-se como método de detecção das citocinas a citometria de fluxo. A concentração de IL-10, após uma hora do exercício, foi significativamente maior em GTE do que GTR. Observou-se maior concentração sérica de TNF-, IL-6 e IL-10 entre os grupos, 24 horas após o exercício, mas sem alteração entre os momentos. A temperatura central se restabeleceu dentro de 24 horas. As temperaturas da região dos tendões em membros pélvicos e da garupa mantiveram-se elevadas. O exercício não causou nenhum tipo de resposta imune, animais condicionados, treinados esporadicamente, apresentaram resposta imune mista enquanto que animais condicionados, treinados regularmente, não apresentaram nenhum tipo de resposta imune. O mecanismo de termorregulação foi eficiente em ambos os grupos, o aumento de temperatu... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aims of this study were to verify if there is inflammation in the exercise of short duration and high intensity and whether it can be classified into Th1, Th2 or Th17. Moreover, check the body temperatures and locations change with exercise of short duration and high intensity and different training can influence these changes. 12 animals were used, 6 female and 6 males, mean age 3 to 6 years and weight ∼ 450 kg. Animals were divided in two groups: regular training (GLTR) and sporadic training (GLTE). 10 mL of Blood were collected in tube without anticoagulant. Blood collections and temperatures were made 30 minutes before, immediately after, and one, two, six and 24 hours after competition. The analyses were made by flow cytometric. The serum concentration of IL-10 was significantly higher in GTE than in GTR. The serum concentrations of TNF-, IL-6 and IL-10 were significantly higher in GTE than in GTR, 24 hours after exercise. The core temperature increased after exercise and returned to baseline after 24 hours. The temperature in the region of the hindlimbs raised immediately after exercise and did not return to baseline after 24 hours. The temperature of the croup (right side) increased immediately after exercise and remained so for more than 24 hours. The exercise did not cause any immune response, conditioned animals, trained sporadically showed mixed immune response while conditioned animals, trained regularly, did not show any immune response. The thermoregulatory... (Complete abstract click electronic access below) / Doutor
42

Modelling and monitoring nonlinear acoustic phenomena in high-intensity focused ultrasound therapy

Jackson, Edward James January 2015 (has links)
High intensity focused ultrasound (HIFU) provides a wide range of noninvasive therapies ranging from drug delivery to the destruction of kidney stones. In particular, thermal ablation by HIFU presents an effective noninvasive method for the treatment of deep seated solid tumours. HIFU’s further uptake is limited by a need for improved treatment planning and monitoring. Two nonlinear acoustic phenomena that play key roles in HIFU treatment: finite amplitude effects that lead to the generation of harmonics and steepening of wavefronts, and acoustic cavitation. The former must be taken into careful consideration for treatment planning purposes, while the latter has the potential to provide fast, real-time, cost effective treatment monitoring. The first half of this thesis provides new measurements for the nonlinear acoustic properties of tissue, assesses the validity of two common modelling techniques for simulating HIFU fields. The second half develops a new method for combining passive acoustic mapping- an ultrasound monitoring technique- with MR thermometry, to assess estimates of cavitation enhanced heating derived from passive acoustic maps. In the first results chapter B/A was measured in ex-vivo bovine liver, over a heating/ cooling cycle replicating temperatures reached during HIFU ablation, adapting a finite amplitude insertion technique (FAIS), which also allowed for measurement of sound-speed and attenuation. The method measures the nonlinear progression of a plane-wave through liver and B/A was chosen so that numerical simulations matched measured waveforms. Results showed that attenuation initially decreased with heating then increased after denaturation, sound-speed initially increased with temperature and then decreased, and B/A showed an increase with temperature but no significant post-heating change. These data disagree with other reports that show a significant change and suggest that any nonlinear enhancement in the received ultrasound signal post-treatment is likely due to acoustic cavitation rather than changes in tissue nonlinearity. In the second results chapter two common methods of modelling HIFU fields were compared with hydrophone measurements of nonlinear HIFU fields at a range of frequencies and pressures. The two methods usedwere the KZK equation and the commercial package PZFlex. The KZK equation has become the standard method for modelling focused fields, while the validity of PZFlex for modelling these types of transducers is unclear. The results show that the KZK equation is able to match hydrophone measurements, but that PZFlex underestimates the magnitude of the harmonics. Higher order harmonics in PZFlex are not the correct shape, and do not peak around the focus. PZFlex performs worse at higher pressures and frequencies, and should be used with caution. In the final two chapters a system for estimating cavitation-enhanced heating from acoustic maps is developed and benchmarked against magnetic resonance thermometry methods. The first chapter shows that the ultrasound and MR monitoring systems are compatible, and registers the two imaging systems. The HIFUfocus is clearly visible in passive maps acquired in the absence of cavitation and these coincide with the centre of heating in MR temperature images. When cavitation occurs, it coincides spatially and temporally with the appearance of a clear spike in temperature, especially when the passive maps are processed using the Robust Capon Beamformer algorithm. The final chapter shows how passive maps can be converted into thermal heating inputs, and used to estimate cavitation-enhanced temperature increases. These estimates have the potential to closely match maximum temperature rise, and estimated thermal dose after the estimated temperature rise is spatially averaged. However, themethod is not always successful. This is partly due to uncertainties in MR thermometry estimates, partly due to uncertainties in the acoustic properties of tissue.
43

Sistema de monitoramento de temperatura e umidade em silos graneleiros via rádio

Ferrasa, Marcelo [UNESP] 01 December 2008 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:31:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-12-01Bitstream added on 2014-06-13T19:20:45Z : No. of bitstreams: 1 ferrasa_m_dr_botfca.pdf: 4410782 bytes, checksum: b6c63787a174343b26f5a0ba21755f4b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O uso das Tecnologias da Informação e Comunicação tem crescido nas mais variadas atividades agrícolas. Como conseqüência, vem revolucionando a forma de pensar e agir do produtor que almeja se estabelecer em um mercado cada vez mais competitivo. Entretanto, o alto custo de aquisição e manutenção dessas tecnologias é um fator que pode inibir sua disseminação e aceitação, principalmente a um grande número de pequenos produtores de grãos. Diante desse cenário, há uma necessidade de soluções inovadoras adequadas a esse universo de produtores. Partindo-se dessa premissa, este trabalho apresenta o desenvolvimento de um protótipo de baixo custo para o monitoramento de temperatura e umidade de grãos armazenados em silos, utilizando uma tecnologia de comunicação sem fio por radiofreqüência. Para tanto, foram analisadas as implicações econômicas de custo/benefício do emprego inovador da transmissão sem fio no processo de termometria de grãos. O protótipo foi composto por duas unidades eletrônicas, uma de aquisição e outra de recepção de dados, além de um programa computacional que ofereceu ao produtor informações mais precisas para o controle da aeração. Por meio de testes realizados quanto à estabilidade, integridade e confiabilidade da transmissão de dados via rádio, utilizando componentes eletrônicos de baixo custo, pode-se considerar o sistema desenvolvido potencialmente viável. Este apresentou o diferencial da comunicação sem fio via rádio no processo de termometria de grãos, proporcionando mobilidade, minimizando custos com cabeamento, manutenção e oferecendo facilidades para sua expansão; também adequou-se ao monitoramento de temperatura eumidade de grãos em silos; e mostrou-se com viabilidade operacional, além do baixo custo de desenvolvimento quando comparado a produtos similares encontrados no mercado brasileiro. / The use of Information and Communication Technology has grown in most agricultural activities. As a consequence, it has changed the way of thinking and acting of the farmer who wants to establish in a more and more competitive market. However, the high costs of acquisition and maintenance of those technologies may be a factor which can inhibit its spread and acceptance, mainly to a large number of small grain Brazilian farmers. In this context, there is a need for innovative solution which are proper for this universe of farmers. Starting from this premise, this paper presents the development of a low cost prototype to the monitoring process of temperature and humidity values of grains stored in silos, using communication based on wireless technology by radio frequency. Therefore, the economic implications of cost/benefit ratio of innovative application of wireless transmission in the process of thermometry of grains were analysed. The prototype was made of two electronic units, one of acquisition and another one of data reception, as well as a computational software, which offered the farmer more precise information for the control of aeration. By means of stability, integrity and reliability tests of data transmission via radio, using low cost electronic components, the development system can be considered as potentially viable. It presented the difference regarding the wireless communication via radio in the process of grains thermometry, providing mobility, reducing cabling costs and maintenance, and also offering an easy system expansion; it was also appropriate to temperature and humidity monitoring in grain silos; and revealed operational viability, besides 4 the low cost development when compared to similar products available in the Brazilian market.
44

Geothermal Potential of Sub-Volcanic Intrusions in a Typical Caldera Setting / Geotermisk potential av magma-intrusioner i en calderavulkan

Gestsson, Einar Bessi January 2018 (has links)
Sub-volcanic intrusions can form an extensive network of sills, dikes and other intrusion types that make up a plumbing system beneath volcanoes. Such intrusions are the heat source for high-temperature geothermal systems in volcanic areas and therefore, it is of great importance to study them in relation to geothermal exploration and production. In this thesis a part of the plumbing system of Breiðuvík caldera, an eroded central volcano in northeastern Iceland, is studied. A set of magmatic intrusions showing a great range in size and shapes, is exposed in Leirfjall, a mountain composed of the eroded caldera infill of the Breiðuvík volcanic system. Data from these intrusions and their host rock is used as the foundation for numerical modeling using finite element method (FEM) constructed in this thesis. The numerical modeling assumes heat transfer in porous media including conduction and convection where fluid flow is governed by the Darcy‘s law. The aims of it is to compare the cooling times of different intrusions and the temperature distribution caused by intrusions of different sizes and shapes. To obtain input parameters for the numerical modeling, a thermometry study based on the mineral chemistry of the magmatic intrusions in Leirfjall is conducted and the thermal and physical properties of the sedimentary host rock are estimated, while literature values are used for basaltic lava and hyaloclastite host rocks for comparison. The results of the numerical modeling suggest that higher maximum values of increased temperature are reached above one thick intrusions compared to multiple thinner intrusions. When comparing dikes and sills, the dikes raise the maximum temperature of the host rock more than the sills, while the sills raise the average temperature above the intrusions more than dikes. Results of the estimated heat transfer from an arrangement of intrusions similar to what is observed in Leirfjall suggests that a significant increase in maximum increased temperature caused by the intrusions would be short-lived, while the average increase would still be constant over a longer time. Despite of the simplified structure of the numerical models it is the hope that they will provide inspiring data for further research and contribute to a better understanding of the relationship between the shallow magmatic intrusions and geothermal systems. / Vulkaner är en viktig energikälla i många länder runt om i världen. Geotermisk vätska och ånga av högtemperatur som finns i vulkanområden kan utnyttjas för bland annat elproduktion och fjärrvärme. Värmekällan till de geotermiska områdena är magma som ligger ytligt i jordskorpan. All magma når inte ytan i utbrott, utan stannar under vulkanen i form av magmaintrusioner. Intrusionerna av olika former och storlekar utgör ett nätverk som tillsammans utgör vulkanens magma transportsystem. I denna studie studeras en uppsättning av magmaintrusioner på nordöstra Island. Intrusionerna har en gång befunnit sig längre ner i jordskorpan under ett aktivt vulkanområde men exponeras nu vid ytan på grund av glacial erosion. Intrusionernas storlek och form varierar, men de flesta återfinns som gångar, både vertikala och horisontella. När en magmatintrusion bildas värms omkringliggande berggrund och grundvatten upp. Studiens fokus är att undersöka hur temperaturfördelningen i omgivningen skiljer sig vid en stor intrusion jämfört med flera mindre intrusioner med totalt samma volym. Även effekten från olika typer av berggrund runt intrusionerna studerades genom att jämföra temperaturfördelningen och kylningstiderna för intrusioner i tre vanliga bergarter. Numerisk modellering användades för att besvara dessa frågor. Bergarternas fysiska och termiska egenskaper krävdes som ingångsparametrar för den numeriska modelleringen. Parametrana uppskattades genom laboratorieexperiment och termometriberäkningar från fältprover. Värden från publicerat material användes också i modelleringen. Resultaten från den numeriska modelleringen antyder att högre maximivärden för temperaturen nås i berget över en stor, enskild intrusion jämfört med flera mindre intrusioner. När man jämför vertikala og horisontella gångar, ökar de vertikala gångarna berggrundens temperatur mer än de horisontella, medan medeltemperaturen ökar mer över horisontella gångar än i vertikala gångar. Trots den numeriska modellens förenklade struktur är förhoppningen att den nya datan kan inspirera vidare forskning, och bidra till en bättre förståelse om förhållandet mellan grunda magmaintrusioner och geotermiska system.
45

Uso da termometria de infravermelho na predição de tolerância ao calor em trigo em dois ambientes de cultivo / Use of infrared thermometry and the evaluation of agronomic traits in wheat cultivar heat tolerance prediction

Tobar, Laura Maritza Saavedra 03 December 2013 (has links)
Made available in DSpace on 2015-03-26T13:40:01Z (GMT). No. of bitstreams: 1 texto completo.pdf: 716927 bytes, checksum: 2d7eff1a3130da5b28fc4573144a70c4 (MD5) Previous issue date: 2013-12-03 / Even though wheat is originated from cold climates, the use of adapted cultivars allows its production in regions with tropical climates, but high temperatures during the crop cycle may become one of the main factors that cause abiotic stress, limiting the well development of the plant and, consequently, a drastic decline in the productivity potential. The wheat production in the central region of Brazil is observed to have been affected because of the increases in temperature which are presented during the different phenological stages, becoming alike to the main limiting factor to its full development. The knowledge of methodologies that are easy to access and are of practical use, which are efficient for plant selection in field conditions is indispensable for the recognition and obtainment of cultivars with tolerance to heat. The objective of this work was to Evaluate canopy temperature depression through the use of infrared thermometry and agronomic traits in wheat cultivars, sown in pots with soil in through conventional cultivation with the intent to compare cultivar reaction to each environment, aiming to confirm which of these present tolerance to heat stress.The experiment was conducted at the Experimental Station Professor Diogo Alves de Melo - of the Federal University of Viçosa (UFV), Viçosa-MG. A completely randomized design was utilized. Six cultivars are utilized for use in the central region of Brazil: Aliança, Anahuac, Embrapa 22, BRS 254, BRS 264 and BRS 207. The cultivars were sown towards the end of July with varying temperatures throughout the development of the plant. There were no significant differences between cultivars when comparing the decline in the temperature of the evaluated plant organs. Only local effects were existent, which was attributed to the fact that, during the general culture development the average air temperature didn't reach values that are considered stressful, being found between 18 and 21° which is considered an C, ideal temperature range for wheat culture. The occurrence of winds may have reduced the canopy temperature of the plants sown in pots, which made these present higher temperature decline values when compared to plants cultivated in the environment's soil. Most of the agronomic traits evaluated present significant differences between environments and between cultivars, being that the pots' environment had the highest average values except for the harvesting index and the weight of one thousand grains, which were bigger in the conventional cultivation. / Mesmo o trigo sendo originário de climas frios, o uso de cultivares adaptadas possibilita sua produção em regiões de climas tropicais, mas as altas temperaturas durante seu ciclo podem tornar um dos principais estresses abióticos, limitando seu bom desenvolvimento e, consequentemente, levando a diminuição drástica no potencial produtivo. A produção de trigo na região central do Brasil é afetada devido aos incrementos da temperatura que se apresentam durante os diferentes estados fenológicos da planta. Deste modo, o conhecimento de metodologias de acesso fácil e de uso prático, que sejam eficientes para a seleção de plantas em condições de campo é imprescindível para a identificação e a obtenção de cultivares com tolerância ao calor. O objetivo deste trabalho foi Avaliar a depressão da temperatura do dossel por meio do método da termometria infravermelha e caracteres agronômicos em cultivares de trigo, semeadas em vasos com solo e em cultivo convencional a fim de comparar o comportamento das cultivares nos dois ambientes, visando qual destas apresentam tolerância ao estresse de calor. O experimento foi conduzido na Estação Experimental Prof. Diogo Alves de Melo da Universidade Federal de Viçosa (UFV), Viçosa-MG. Utilizou-se o delineamento experimental inteiramente casualizado. As cultivares avaliadas foram: Aliança, Anahuac, Embrapa 22, BRS 254, BRS 264 e BRS 207, sendo semeadas no final do mês junho com temperaturas variáveis ao longo do desenvolvimento das plantas. A depressão da temperatura no dossel não apresentou diferenças entre as cultivares. O efeito apresentado foi de local, o que foi atribuído ao fato de que, durante o desenvolvimento das plantas o ambiente não apresentou estresse acentuado pelo calor, considerando que a temperatura média do ar encontrava-se numa faixa entre 18 a 21° considerada adequada para o desenvolvimento da cultura de C, trigo. A ocorrência de ventos possivelmente reduziu a temperatura no dossel das plantas cultivadas em vasos, fazendo com que estas apresentassem maiores valores de depressão de temperatura em comparação com as plantas cultivadas no solo. Para a maioria dos caracteres agronômicos avaliados houve diferença significativa entre ambientes e entre cultivares, apresentando-se o ambiente nos vasos com maiores valores de médias, exceto o índice de colheita e massa de mil grãos que foram maiores no cultivo convencional.
46

Perfil de citocinas séricas e termografia em equinos quarto de milha submetidos à prova de laço em dupla / Profile of serum cytokines and thermography in quarter horses subjected to team roping

Gerardi, Bianca [UNESP] 25 July 2016 (has links)
Submitted by Bianca Gerardi null (bi_gerardi@hotmail.com) on 2016-08-04T00:47:26Z No. of bitstreams: 1 Perfil de citocinas séricas e termografia em equinos quarto de milha submetidos à prova de laço em dupla - Bianca Gerardi.pdf: 1625786 bytes, checksum: 2e6e055878a273e0a82f20dbda6fefe2 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-08-09T13:38:34Z (GMT) No. of bitstreams: 1 gerardi_b_dr_araca.pdf: 1625786 bytes, checksum: 2e6e055878a273e0a82f20dbda6fefe2 (MD5) / Made available in DSpace on 2016-08-09T13:38:34Z (GMT). No. of bitstreams: 1 gerardi_b_dr_araca.pdf: 1625786 bytes, checksum: 2e6e055878a273e0a82f20dbda6fefe2 (MD5) Previous issue date: 2016-07-25 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os objetivos do presente estudo foram verificar se existe reação inflamatória no exercício de curta duração e alta intensidade e se a mesma pode ser classificada em Th1, Th2 ou Th17. Além disso, verificar se as temperaturas corpóreas e locais se alteram com exercício este e se treinamentos distintos podem influenciar nestas alterações. Utilizaram-se 12 animais, idade entre 3 e 6 anos e peso médio de 450 kg, participantes de laço em dupla, divididos em: treino regular (GTR) e treino esporádico (GTE). O sangue coletado em tubos de 10 ml sem anticoagulante. Coletas e aferições de temperatura foram realizadas 30 minutos antes, imediatamente depois, uma, duas, seis, e 24 horas após o exercício. Utilizou-se como método de detecção das citocinas a citometria de fluxo. A concentração de IL-10, após uma hora do exercício, foi significativamente maior em GTE do que GTR. Observou-se maior concentração sérica de TNF-, IL-6 e IL-10 entre os grupos, 24 horas após o exercício, mas sem alteração entre os momentos. A temperatura central se restabeleceu dentro de 24 horas. As temperaturas da região dos tendões em membros pélvicos e da garupa mantiveram-se elevadas. O exercício não causou nenhum tipo de resposta imune, animais condicionados, treinados esporadicamente, apresentaram resposta imune mista enquanto que animais condicionados, treinados regularmente, não apresentaram nenhum tipo de resposta imune. O mecanismo de termorregulação foi eficiente em ambos os grupos, o aumento de temperatura local após 24 horas pode ser infleuenciado pela temperatura ambiente ou ser sugestivo de inflamação subclínica. / The aims of this study were to verify if there is inflammation in the exercise of short duration and high intensity and whether it can be classified into Th1, Th2 or Th17. Moreover, check the body temperatures and locations change with exercise of short duration and high intensity and different training can influence these changes. 12 animals were used, 6 female and 6 males, mean age 3 to 6 years and weight ∼ 450 kg. Animals were divided in two groups: regular training (GLTR) and sporadic training (GLTE). 10 mL of Blood were collected in tube without anticoagulant. Blood collections and temperatures were made 30 minutes before, immediately after, and one, two, six and 24 hours after competition. The analyses were made by flow cytometric. The serum concentration of IL-10 was significantly higher in GTE than in GTR. The serum concentrations of TNF-, IL-6 and IL-10 were significantly higher in GTE than in GTR, 24 hours after exercise. The core temperature increased after exercise and returned to baseline after 24 hours. The temperature in the region of the hindlimbs raised immediately after exercise and did not return to baseline after 24 hours. The temperature of the croup (right side) increased immediately after exercise and remained so for more than 24 hours. The exercise did not cause any immune response, conditioned animals, trained sporadically showed mixed immune response while conditioned animals, trained regularly, did not show any immune response. The thermoregulatory mechanism was efficient in both groups, the local temperature increase after 24 hours due to room temperature or suggestive of subclinical inflammation. / FAPESP: 2014/09362-5
47

Cardiac MR thermometry for the monitoring of radiofrequency ablation / Thermométrie IRM pour le suivi des ablations radiofréquences sur le cœur

Toupin, Solenn 07 December 2016 (has links)
Le traitement des arythmies cardiaques par ablation radiofréquence est une procédure thérapeutique permettant de restaurer un rythme normal par destruction thermique des tissus arythmogènes. A l'heure actuelle, l'intervention est réalisée sans imagerie temps réel permettant de visualiser la lésion pendant l'ablation. La thermométrie IRM permet de mesurer la température du tissu en chaque pixel et d'estimer directement l'étendue de la lésion via le calcul de la dose thermique cumulée. Si cette technique est déjà établie pour guider l'ablation de tumeurs dans différents organes, elle reste difficile à mettre en œuvre sur le cœur, notamment à cause des mouvements de respiration et de contraction myocardique. Dans le cadre de cette thèse, une méthode de thermométrie cardiaque a été implémentée pour réaliser une cartographie temps réel de la température du myocarde en condition de respiration libre. Plusieurs séquences IRM rapides ont été développées pour permettre l'acquisition d'environ 5 coupes par battement cardiaque avec une taille de voxel de 1.6X1.6X3 mm3. Plusieurs solutions de réduction des mouvements hors plan de coupe ont été évaluées : positionnement des coupes dans le sens principal du déplacement, suivi dynamique de la position des coupes en fonction de l'état respiratoire (navigateur, mesure de la position du cathéter). Le mouvement résiduel et les artéfacts de susceptibilité associés sont corrigés par des algorithmes temps réels pour permettre une précision de la thermométrie IRM à ±2°C sur les ventricules. Ce protocole a été utilisé avec succès pour le suivi d'ablations radiofréquences chez la brebis (N=3), permettant une corrélation (R=0.87) entre la dose thermique et la taille réelle des lésions induites. Les résultats sont très prometteurs quant à la pertinence de cette mesure pour une estimation en ligne de l'étendue de la lésion pendant l'ablation. Ces méthodes permettent d'envisager une évaluation clinique à court terme. / Radiofrequency ablation is a therapeutic procedure for the treatment of cardiac arrhythmia by inducing a local necrosis of the arrhythmogenic tissue. This intervention is currently performed without online imaging of the lesion formation during radiofrequency delivery. MR thermometry provides a monitoring of temperature in the targeted tissue in each pixel and an immediate estimation of lesion via the calculation of the thermal dose. If this technique is well established for the guidance of tumor ablation in various organs, it remains challenging in the heart due to motion (breathing and myocardial contraction). In this work, a cardiac MR thermometry method was developed to perform a real-time temperature mapping of the heart under free-breathing conditions. Several MR pulse sequences were designed to ensure the acquisition of up to 5 slices per heartbeat with a voxel size of 1.6X1.6X3 mm3. Different solutions of minimization of out-of-plane motion were evaluated: alignment of the slices in the main direction of displacement, dynamic update of slice position depending on the respiratory state (echo-navigator, measure of the catheter position). Residual in-plane motion and associated susceptibility artifacts were corrected by real-time algorithms to allow a precision of MR thermometry of ±2°C in ventricles. This protocol was successfully used for the monitoring of radiofrequency ablation in sheep (N=3), allowing a correlation (R=87) between thermal dose maps and sizes of created lesions. These results are promising regarding the relevance of this measure for an inline estimation of the lesion extent during ablation.
48

New approaches for high spatial and temporal resolution nanothermometry : development of hot wire nano heater devices and investigation of thermosensitive materials with fluorescent and spin crossover properties / Nouvelles approches de la nanothermométrie à hautes résolutions spatiales et temporelles : développement de dispositifs de chauffage à l'échelle nanométrique et études de matériaux thermosensibles par la fluorescence et les propriétés de la transition de spin

Kraieva, Olena 26 October 2015 (has links)
L'objectif de cette thèse était de développer de nouvelles méthodes micro- et nano-thermométriques proposant de hautes résolutions spatiales et temporelles. Dans ce cadre nous nous sommes concentrés sur deux tâches : dans un premier temps, nous avons développé un dispositif de nano-chauffage qui peut aisément servir à la caractérisation thermo-physique de matériaux à l'échelle nanométrique. Dans un second temps, en utilisant cette plate-forme nous avons étudié des matériaux thermosensibles, incluant divers luminophores et des complexes à transition de spin ainsi que leurs mélanges. Les dispositifs de nano-chauffage, basés sur des nanofils chauffés par effet Joule, ont été fabriqués par lithographie électronique conventionnelle. Grâce à leur faible inertie thermique, les dispositifs basés sur des nanofils sont particulièrement intéressants en termes de temps de réponse et de confinement des changements de température induits. La caractérisation thermique de ces éléments de chauffage a été réalisée à l'aide de méthodes électriques et optiques ainsi que de simulations par éléments finis. Nous avons montré expérimentalement que nos chauffages prodiguent des perturbations en température (1 K < DeltaT < 80 K) rapides (< µs) et spatialement localisées (< µm) lorsque stimulées par des impulsions de courant électrique. Les simulations par éléments finis reproduisent ces résultats expérimentaux avec une bonne précision et prouvent ainsi leur intérêt pour le design de tels dispositifs. Les performances thermométriques de matériaux fluorescents, incluant des colorants organiques (Rhodamine B), des nanoparticules inorganiques (PbF2:Er3+/Yb3+, CdSe) et des nanoparticules hybrides organiques/inorganiques ([Fe(Htrz)2(trz)]BF4@SiO2-pyrene), ont ensuite été étudiées. D'une manière générale, leur intérêt pour l'imagerie thermique a été démontré, mais des problèmes de stabilité rendent les mesures quantitatives difficiles avec de tels matériaux. D'un autre côté, nous avons réussi à synthétiser des films de nanoparticules du complexe à transition de spin [Fe(Htrz)2(trz)]BF4 (non-dopé). Ces films qui nous ont permis de suivre les changements de température à l'aide de mesures de réflectivité optique plus robustes. La boucle d'hystérèse thermique dans ce matériau procure un effet de mémoire thermique à long terme dont nous avons usé avec succès pour imager les changements de température très rapides (< µs) et spatialement localisés (< µm) - même après que la chaleur se soit dissipée. Cette méthode originale nous procure une combinaison sans précédent de sensitivité spatio-temporelle dans le champ de la nano-thermométrie aux applications pratiques prometteuses. / The overall objective of this PhD thesis was to develop novel micro- and nano-thermometry methods providing high spatial and temporal resolution thermal imaging. To achieve this goal we have focused on two tasks: First, we developed a nano-heater device that can be easily employed for the thermo-physical characterization of materials at the nanoscale. In a second time, using this platform we investigated thermo-sensitive materials, including different luminophores and spin crossover complexes as well as their mixtures. The nano-heater device, based on Joule-heated metallic nanowires, was fabricated by standard electron beam lithography. Due to their small thermal mass, nanowire based devices are particularly interesting in terms of response times and also in terms of confinement of the induced temperature changes. The thermal characterization of these heating elements was carried out using electrical and optical methods as well as finite element simulations. We have shown experimentally that our heaters can provide fast (< µs) and spatially well localized (< µm) T-jump perturbations (1 K < DeltaT < 80 K) driven by an electrical current pulse. Finite element simulations reproduced these experimental results with good accuracy and proved to be a powerful tool of prediction for the device design. Fluorescent materials, including organic dyes (Rhodamine B), inorganic nanoparticles (PbF2:Er3+/Yb3+, CdSe) and hybrid organic/inorganic nanoparticles ([Fe(Htrz)2(trz)]BF4@SiO2-pyrene), were then investigated for their thermometry performance. Overall, they were found useful for thermal imaging, but stability problems make quantitative measurements challenging with these materials. On the other hand, we have succeeded in synthesizing nanoparticle films of the (undoped) [Fe(Htrz)2(trz)]BF4 spin crossover complex, which allowed us to infer temperature changes through more robust optical reflectivity measurements. The thermal hysteresis loop in this material provides a long-term thermal memory effect which we used successfully to image very fast (˜µs) transient temperature changes with high spatial resolution (sub-µm) - even when the heat is dissipated. This original method provides an unprecedented combination of spatio-temporal sensitivity within the field of nanothermometry with promising potential applications.
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Měření teploty brzdového kotouče za jízdy vozidla / Brake Disc Temperature Measurement on Moving Vehicle

Mužák, Jaroslav January 2008 (has links)
Subject of this diploma work is to complete preliminary report of possibilities and problems with brake disks monitoring on moving vehicle. A vital condition is to choose appropriate temperature sensor as well as assembling complete measuring set and it’s fastening to the vehicle. Temperature readings from driving tests, after specific brake maneuvers, will be evaluate and according to them a sensor will be determined as appropriate or inappropriate for this kind of tests.
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Avaliação objetiva de teste cutâneo de leitura imediata (skin prick test) através de métodos planimétricos por imagem, e termometria da reação

Almeida, Ana Laura Mendes January 2020 (has links)
Orientador: Rafael Plana Simões / Abstract: The skin prick test is used to diagnose patients' sensitization to antigens through a mediated IgE response. It is a practical and quick exam, but its diagnosis depends of instruments for measuring the allergic response and observer's interpretation. The conventional method for inferring about the allergic reaction is performed from the dimensions of the papules, which are measured using a ruler or a caliper. To make this diagnosis less dependent of human interpretation, the present study proposes two alternative methods to infer about the allergic reaction: computational analysis of the papule area and a study of the temperature variation of the patient's skin in the puncture region. For this purpose, the histamine prick test was performed on 13 patients random selected. The areas were determined by the conventional method using the dimensions of the papules measured with a digital caliper 30 minutes after the puncture. The papule areas were also determined by a Python algorithm using photos of the puncture region obtained by a smartphone. A variable named circularity deviation was also determined for each analyzed papule. The temperature variation was monitored using an infrared temperature sensor, which collected temperature data for 30 minutes. The results shown that the areas considered as real papule areas (computationally determined) differed significantly from the areas determined by the conventional method (p-value = 0.0005674), especially when the papules' contours ... (Complete abstract click electronic access below) / Resumo: O teste cutâneo de leitura imediata (skin prick test) é utilizado para avaliar a sensibilização de pacientes a antígenos à partir de uma resposta mediada por IgE. Tratase de um exame prático e rápido, porém o seu diagnóstico depende de instrumentos para a medição da resposta alérgica e de intepretação do observador. O método convencional para inferir sobre a reação alérgica é realizado a partir de dimensões das pápulas determinadas com régua ou paquímetro. Para tornar o diagnóstico menos dependente de interpretação humana, o presente estudo propõe dois métodos alternativos para inferir sobre a reação alérgica: análise computacional da área da pápula e um estudo da variação da temperatura da pele do paciente na região de puntura. Para isso foi realizado o prick test com histamina em 13 participantes selecionados aleatoriamente. A determinação da área pelo método convencional foi realizada a partir de dimensões das pápulas medidas com paquímetro digital 30 minutos após a puntura. A área também foi determinada utilizando um algoritmo computacional em linguagem Python a partir de fotografia da região de puntura obtida com o uso de um smartphone. Também foi determinada uma grandeza denominada desvio de circularidade para cada pápula analisada. Por final, a variação da temperatura da região de puntura foi monitorada utilizando um sensor infravermelho de temperatura, o qual coletou dados de temperatura durante 30 minutos. Os resultados mostram que as áreas consideradas como áreas re... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

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