This project revolves around the measurement of T1 and T2 relaxation times in the ratbrain, in a multi-center way. That is to say, elaborate an efficient protocol to calculate highresolution 3D map of the brain. This protocol should be applied in different centers andreturn similar results. Finally, procedures should be defined to ease the collaborationbetween the different centers. The first step consisted in in vitro experiments, in whichdifferent sequences were tested. It resulted that the MDEFT sequence with inversionpreparation (MPRAGE) gives the best results in the shortest time for T1. For T2, theMSME sequence was chosen. The next step moved on in vivo experiments on three rats inorder to get used to manipulating living animals and make new adjustments. As thephysiology is not the same on in vitro and in vivo experiments, some parameters had to beslightly adapted. Once the final 2h-protocol was established, it was tested on a populationof ten rats. Experiments were made at the GIN and CRMBM. Different fitting pipelineswere tried (GIN, CRMBM, MIRCEN). The brain was segmented into different regions. Itresulted that the GIN and CRMBM pipelines return the same T1 values using the differentdatasets. The MIRCEN pipeline under-estimates by 200 ms. The three pipelines return similar T2 values. The GIN and CRMBM datasets provide comparable T1 values, but theGIN center presents slightly higher T2 values. Regarding the multi-center collaboration,the different pipelines were ported to the VIP platform so that the scientific community caneasily reuse them.

Background Knee osteoarthritis is a degenerative joint disease characterized by damaged cartilage, tendons, ligaments, synovium, and bone. Knee osteoarthritis causes joint pain, reduced joint function, and decreased quality of life and is the leading cause of chronic disability in older adults. Two of the major risk factors for knee osteoarthritis are increasing age and obesity. To decrease the occurrence of knee osteoarthritis in our aging population, it is important that we identify exercises that are safe for people with or at risk of knee osteoarthritis. Purpose The main purpose of this thesis was to compare the acute response of knee cartilage composition to two common aerobic activities, running and bicycling, of equal total load. To address the primary purpose, we first sought to determine the reliability and validity of measuring loading repetition during running (steps) and bicycling (pedal-revolutions) using accelerometry. Methods 1) Twenty-two healthy adults completed running and bicycling activity bouts (five-minutes) while wearing six accelerometers: two at each the waist, thigh and shank. Accelerometer and video data were collected during each activity. 2) Fifteen healthy men completed running and bicycling activities of equal cumulative load that were preceded and followed by a series of magnetic resonance images. Results 1) Excellent reliability (ICC≥.99; SEM≤1.0) and validity (Pearson≥.99) were found for step and pedal revolution measurements taken by an accelerometer placed at the shank. 2) Bicycling did not cause significant changes in cartilage composition (p=0.274); however, running did cause a change in cartilage composition (p=0.002). Conclusion Findings from this thesis suggest that to acquire reliable and valid step and pedal revolution measurement, accelerometers should be placed on the shank. Furthermore, bicycling causes no statistical changes in knee cartilage, while running does. Bicycling may therefore be used to combat obesity and maintain cardiovascular health in individuals with compromised joint health. / Thesis / Master of Science (MSc) / Knee osteoarthritis is a degenerative joint disease that affects all knee tissues, particularly articular cartilage. This “wear and tear” condition reduces mobility and creates pain, collectively decreasing quality of life. Two important risk factors for knee osteoarthritis are age and obesity. While we cannot stop aging, exercise can have a positive impact on weight, particularly among adults with knee osteoarthritis. This thesis provides foundational information on how running and bicycling affects knee cartilage. First, we identified a useful method of measuring steps during running and pedal revolutions during bicycling. Second, we compared the effect of running and bicycling of equal cumulative load on knee cartilage, using MRI. The running activity was 1/3 the length of the bicycling activity but despite shorter exposure, running caused changes in cartilage shape and composition, while bicycling did not. These findings suggest that bicycling is a suitable aerobic activity that reduces loading at the knee.

No description available.

No description available.

No description available.

[EN] The Statistical Process Control (SPC) is a method used to control the quality characteristics of a product during the production process, determine whether the manufacturing process is or not stable and improve its capacity through the reduction of variability. One of the main tools used in the SPC is the control chart. Often the quality of a product is measured through various quality characteristics generally correlated. Multivariate Control charts are a response to the need for quality control in such situations. If the quality characteristics are qualitative, sometimes it happens that the product quality is defined by linguistic variables and product units are also classified by linguistic forms into several categories, depending on the degree of fulfillment of expectations, creating a situation of fuzzy classifications. The control charts proposed in the literature to deal with such situations are mostly based on simulation and using approximation techniques which hinder the practical application thereof. This thesis addresses this issue proposing a multivariate control chart for quality characteristics of multi-type attributes correlated based on the T2 control chart of Hotelling, using a fuzzy approach. The results of the proposed control charts before are improved by establishing a more formal way of measuring and evaluating quality in these diffuse situations. A method is also proposed to assess the performance of control chart proposed, by deter mining the average run length (ARL), in both in-control state and the out-of-control state. For this, algorithms which use Monte Carlo simulation are developed and implemented in R. Additionally, the sensitivity of the control chart faced with the choice of the membership functions of linguistic variables is analyzed. / [ES] El Control Estadístico de Procesos (CEP) es un método que se utiliza para controlar las características de calidad de un producto durante el proceso de producción, determinar si los procesos de manufactura son o no estables y mejorar su capacidad a través de la reducción de la variabilidad. Una de las principales herramientas utilizadas en el Control Estadístico de Procesos es el gráfico de control. Con frecuencia, la calidad de un producto se mide a través de varias características de calidad, generalmente correlacionadas. Los gráficos de control multivariantes son una respuesta a la necesidad de controlar la calidad en tales situaciones. Si las características de calidad son de carácter cualitativo, ocurre en ocasiones que la calidad del producto se define mediante variables lingüísticas y las unidades de producto se clasifican también de for ma lingüística en varias categorías, dependiendo del grado de cumplimiento de las expectativas, creando una situación de clasificaciones difusas. Los gráficos propuestos en la literatura para tratar con tales situaciones están, en su mayoría, basados en simulación y el uso de técnicas de aproximación que dificultan la aplicación práctica de los mismos. Esta tesis trata esta cuestión proponiendo un Gráfico de Control multivariante para características de calidad de tipo multi-atributos correlacionados basado en el gráfico T2 de Hotelling, utilizando un enfoque difuso. Se mejora los resultados de los gráficos de control propuestos anterior mente estableciendo una manera más formal de medición y evaluación de la calidad en estas situaciones difusas. Se propone además un procedimiento para evaluar el rendimiento del gráfico de control propuesto mediante la determinación de la longitud de racha promedio (ARL), tanto para un estado bajo-control como para el estado fuera-de-control. Para ello se desarrollaron algoritmos que utilizan simulación de Monte Carlo y han sido implementados en R. Adicionalmente, se analiza la sensibilidad del gráfico de control frente a la elección de las funciones de pertenencia de las variables lingüísticas. / [CA] El Control Estadístic de Processos (CEP) és un mètode que s'utilitza per controlar les característiques de qualitat d'un producte durant el procés de producció, deter minar si els processos de manufactura són o no estables i millorar la seva capacitat a través de la reducció de la variabilitat. Una de les principals eines utilitzades en el Control Estadístic de Processos és el gràfic de control. Sovint, la qualitat d'un producte es mesura a través de diverses característiques de qualitat, generalment correlacionades. Els gràfics de control multivariants són una resposta a la necessitat de controlar la qualitat en aquestes situacions. Si les característiques de qualitat són de caràcter qualitatiu, de vegades passa que la qualitat del producte es defineix mitjançant variables lingüístiques i les unitats de producte es classifiquen també de for ma lingüística en diverses categories, depenent del grau de compliment de les expectatives, creant una situació de classificacions difuses. Els gràfics proposats en la literatura per abordar aquestes situacions són, majoritàriament, basats en simulació i l'ús de tècniques d'aproximació que en dificulten l'aplicació pràctica. Aquesta tesi tracta de resoldre aquesta qüestió amb la proposta d'un Gràfic de Control multivariant per característiques de qualitat de tipus multi-atributs correlacionats basat en el gràfic T2 de Hotelling, mijançant un enfocament difús. S'hi milloren els resultats de les gràfics de control proposats anterior ment per mitjà d'un mètode més for mal de mesurament i avaluació de la qualitat en aquestes situacions difuses. S'hi proposa a més un procediment per avaluar el rendiment del gràfic de control proposat mitjançant la deter minació de la longitud de ràfega mitjana (ARL), tant per a un estat en-control com per a l'estat fora-de-control. Amb aquesta finalitat es van desenvolupar algoritmes que utilitzen simulació de Monte Carlo i han estat implementats en R. Addicionalment, s'hi analitza la sensibilitat del gràfic de control davant l'elecció de les funcions de pertinença de les variables lingüístiques. / Pastuizaca Fernández, MN. (2016). Diseño y mejora de gráficos de control multivariantes para atributos. Un enfoque basado en teoría difusa [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/65073

Esta tese tem por objetivo o desenvolvimento de metodologias eficientes e de baixo custo para ajustar as propriedades elétricas de OFETs de canal p e de canal n, a fim de possibilitar a fabricação do circuito complementar orgânico, semelhante a uma estrutura CMOS. O desempenho do circuito complementar fabricado foi otimizado, e também foi confeccionado por impressão um OFETs de canal operando em baixas tensões. Para a fabricação do CMOS orgânico foi proposto um método baseado na seleção adequada do solvente da camada dielétrica para ajustar o desempenho elétrico dos OFETs de canal p e de canal n. Os solventes, MEK, nBA e DMSO foram selecionados para a dissolução do PMMA por apresentarem diferenças nos valores de momento de dipolo, de ponto de ebulição e de graus de ortogonalidade em relação as camadas semicondutoras de P3HT e de P(NDI2OD-T2) dos OFETs. A análise dos resultados dos OFETs de canal p e de canal n demonstrou que a metodologia proposta é adequada tanto para o ajuste das propriedades elétricas destes dispositivos quanto para a otimização do desempenho dos mesmos. Os melhores desempenhos elétricos para os OFETs de canal p e de canal n foram obtidos quando utilizados o DMSO e o MEK como solventes do PMMA, respectivamente, devido à perfeita ortogonalidade destes solventes em relação às camadas semicondutoras. Os OFETs de canal p que utilizaram o DMSO e os OFETs de canal n que utilizaram o nBA foram os que apresentaram desempenhos elétricos semelhantes, sendo portanto aplicados na fabricação do CMOS. Valores de ganho entre 6,8 e 7,8 e de margem de ruído entre 28,3 V e 34,5 V foram obtidos para inversores complementares fabricados nesta etapa do trabalho. OFETs de canal p utilizando uma blenda de PTAA: diF TES ADT como camada semicondutora, o PEDOT:PSS como eletrodos dreno/fonte e o P(VDF-TrFE-CFE) como camada dielétrica também foram fabricados neste trabalho. A técnica de blade-coating foi utilizada para a deposição dos eletrodos dreno/fonte e da camada semicondutora, ao passo que a técnica de spray-coating foi utilizada para a deposição da camada dielétrica. Da análise dos resultados foi possível inferir que a utilização de um dielétrico com elevada constante dielétrica (K), como o P(VDF-TrFE-CFE), possibilita o funcionamento dos transistores a baixas tensões (≤ 8 V), porém com valores de mobilidade reduzidos devido à elevada desordem dipolar na interface provocada por este dielétrico. Para minimizar esses efeitos, uma fina camada de um polímero fluorado foi depositada entre a camada semicondutora e a dielétrica pela técnica de blade-coating, constituindo assim uma bicamada dielétrica nos OFETs. Dos resultados das medidas elétricas dos OFETs constituídos pela bicamada dielétrica foi observada permanência do funcionamento destes dispositivos a tensões inferiores a 8 V com desempenho elétricos superiores a resultados já publicados na literatura. Por fim, inversores lógicos unipolares com transistores de carga foram fabricados com os OFETs que utilizaram a bicamada dielétrica, sendo obtidos valores de ganho entre 1,2 e 1,6 e de margem de ruído entre 56% e 68,5% de ½ VDD. / This thesis aimed to develop an efficient and low cost method to adjust the electrical properties of p- and n-channel OFETs to allow us to build an organic CMOS and the optimization of printed p-channel OFETs to work at low voltages. We proposed a method to fabricate the organic CMOS, based on the careful selection of dielectric solvent, which was adjusted to obtain the best performance of p- and n-channel OFETs. The dielectric solvents as MEK, nBA and DMSO were selected to dissolve the PMMA dielectric polymer due their different physical properties as dipole moment and boiling point and because they showed slightly different degrees of orthogonality to the P3HT and P(NDI2OD-T2) semiconductor layers of the OFETs. The results showed that the careful selection of the dielectric solvent not only allows to tune the electrical characteristics of the p- and n-channel OFETs, but also to improve the performance of these devices. The best performances were achieved when DMSO and MEK were used as dielectric solvents of the p and n-channel OFETs, respectively, as result of the perfectly orthogonality of these solvents to the semiconductor layers. P-channel OFETs using DMSO and n-channel OFETs using nBA showed similar electrical characteristics and thus, they were used to construct the organic CMOS. The organic complementary inverters showed high gain and noise margin values in the range of 6,8 to 7,8 and 28,3 V to 34,5 V, respectively. Printed p-channel OFETs were also fabricated, in which the blend PTAA:diF TES ADT was used as semiconductor channel, PEDOT:PSS as the drain/source electrodes and P(VDF-TrFE-CFE) as the dielectric layer. The blade-coating technique was used to deposit the source/drain electrodes and the semiconductor layer, while the spray-coating technique was used to deposit the dielectric layer. It was observed that using high-k dielectric as P(VDF-TrFE-CFE) enable to reduce the operating voltage of the OFETs (≤8 V), however, this high-k dielectric also reduced the field effect mobility due the dipolar disorder at the semiconductor/dielectric interface. To minimize the dipolar issue at the interface, we inserted a thin fluoropolymer dielectric layer by blade-coating between the semiconductor and the high-k dielectric layers, thus constituting a dielectric bilayer on the OFETs. From the electrical measurements of the OFETs with the dielectric bilayer, it was observed that the devices were still working at 8 V and they also showed better performance in comparison to results already published. Finally, organic unipolar inverters with load transistors were fabricated using the p-channel OFETs with the dielectric bilayer and they showed reasonable performance, with gain and noise margin in the range of 1,2 to 1,6 and 56% e 68,5% of ½ VDD, respectively.

L'imagerie par résonance magnétique (IRM) est un outil remarquable pour le diagnostic clinique, aussi bien pour l'imagerie cérébrale que pour l'imagerie cardiaque et abdominale. En IRM cardiaque, deux problèmes sont récurrents : la non reproductibilité des cycles cardiaques et le mouvement respiratoire. L'IRM cardiaque morphologique est généralement faite avec une séquence composée d'une préparation longue, visant à annuler le signal du sang pour accentuer le contraste au niveau du myocarde, et de l?acquisition à proprement parler. Ces acquisitions sont généralement faites en mésodiastole (phase de relaxation passive du coeur) ce qui permet de satisfaire les contraintes liées à l'annulation du sang et d'éviter les problèmes liés aux non reproductibilités des cycles cardiaques car la mésodiastole est longue. Il est donc difficile de satisfaire les contraintes liées à l?annulation du sang pour faire les acquisitions en télésystole (phase où le coeur est contracté) à cause des non reproductibilités cardiaques car la télésystole est courte. Afin de passer outre ces limitations et de pouvoir acquérir ces mêmes images morphologiques en télésystole, nous proposons une nouvelle méthode adaptative qui permet à la fois de placer la fenêtre d'acquisition de manière optimale et de satisfaire les contraintes liées à l'annulation du sang. Une application de cette méthode a également été mise en place pour estimer et comparer les temps de relaxation transversale (T2) entre télésystole et mésodiastole. Pour la gestion prospective du mouvement respiratoire, le point crucial est d'estimer les mouvements en temps réel en perturbant au minimum les signaux de résonance magnétique. Pour ce faire nous proposons une méthode basée sur l'estimation paramétrique des mouvements en temps réel à partir des signaux physiologiques disponibles (ceintures respiratoires et ECG). Cette méthode a été testée et les résultats montrent son intérêt et sa fiabilité par rapport aux erreurs faites au niveau du mouvement. Une méthode de reconstruction incluant les mouvements a également été utilisée pendant ces travaux afin de faire de l'imagerie en télésystole en respiration libre et d'utiliser d'autres types de capteurs respiratoires comme certains signaux de résonance magnétique. Ainsi pendant ces travaux, des méthodes adaptatives ont été mises en place afin de mieux gérer le mouvement et de prendre en compte les spécificités de chaque patient. Ces travaux ouvrent la voie de l'imagerie par résonance magnétique adaptative pleinement fonctionnelle dans un contexte clinique / Magnetic resonance imaging (MRI) is a valuable tool for the clinical diagnosis for brain imaging as well as cardiac and abdominal imaging. In cardiac MRI, there are two challenging issues: the non reproducibility of cardiac cycles and respiratory motion. Morphological cardiac MRI is generally performed with a pulse sequence composed of a long preparation, to cancel the blood signal and thus enhance the contrast of the myocardium, and the acquisition itself. These acquisitions are performed during the mid-diastolic rest (relaxation period of the heart) to satisfy constraints to cancel the blood signal and to avoid problems linked to the cardiac non reproducibility because the mid-diastolic rest is long. Consequently, to acquire images in end-systolic rest (when the heart is fully contracted) while taking into account constraints to cancel the blood signal is not straight forward due to cardiac non reproducibility because the end-systolic rest is short. To overcome these limitations and to acquire images in end-systolic rest, a new adaptive method is introduced that allows to optimally placing acquisition windows while taking constraint for the cancellation of the blood signal into account. This method was applied to measure and compare transverse relaxation time (T2) between end-systolic and mid-diastolic rests. For prospective respiratory motion correction, the crucial point is to estimate motion in real-time without perturbing MR signal used for imaging. In order to solve this issue, a new method is introduced aiming at estimating motion parameters in real-time based on physiological signals such as respiratory bellows and ECG. This method is evaluated and results show its interest and its reliability regarding motion estimation errors. A reconstructions algorithm is also used in order to perform cardiac imaging during the end-systolic rest in free breathing and to use different kind of respiratory motion sensors such as MR signals. Hence, during this research work, several adaptive method were developed to get a better management of motion and to take into account specificity of each patient. These works open the way of fully functional adaptive magnetic resonance imaging in a clinical situation

L'imagerie par Résonance Magnétique (IRM) cardiaque est un domaine qui nécessite d'adapter la séquence au rythme du coeur, afin d'éviter le flou causé par un temps d'acquisition long devant les constantes de temps du mouvement. Ainsi, les temps séparant les impulsions radio-fréquence (RF) de la séquence sont aussi variables que les durées des cycles cardiaques sur lesquels on synchronise l'acquisition. Cela est cause d'imprécision sur l'image résultante, en particulier dans son caractère quantitatif. L'aimantation des spins n'est effectivement pas dans un état d'équilibre sur toute l'acquisition. La thèse présente deux axes principaux de recherche explorés ; le premier est une étude de l'impact de la variation du rythme cardiaque (présentée en outre dans le manuscrit) sur la mesure quantitative du temps de relaxation transversal T2. L'étude a été menée sur des objets fantômes et sur des volontaires sains. Deux méthodes de correction de la variation du rythme sont proposées, l'une basée sur la correction du signal au centre de l'espace de Fourier, l'autre basée sur une approche de reconstruction généralisée. Les résultats préliminaires sont encourageants, et des travaux ultérieurs seraient à entreprendre pour confirmer l'efficacité de ces méthodes. Ensuite, les variations temporelles du cycle cardiaque sont traitées à l'échelle d'un cycle, et nous proposons une méthode de mise en coïncidence des différents segments de l'électrocardiogramme (ECG) basée sur la déformation de l'ECG dans l'IRM probablement par effet magnétohydrodynamique. Cette méthode est mise au service de l'imagerie dans le cadre d'une séquence cinétique CINE dans laquelle une meilleure mise en correspondance des segments de cycles cardiaques successifs devrait permettre de gagner en qualité d'image, à condition d'avoir des résolutions spatiale et temporelle suffisamment fines. Les résultats apportés au cours de cette thèse sont préliminaires à de futures recherches nécessaires dans le domaine temporel de la séquence, beaucoup moins traité que le mouvement des organes / Cardiac Magnetic Resonance Imaging (MRI) requires to adapt the sequence to heart rate, so as to avoid the blur caused by the acquisition time longer than motion time constants. Thus, times between sequence radiofrequency pulses are as much variable as synchronization cardiac cycles durations. It causes imprecision on the resulting image, particularly for quantification. In fact, spins magnetization is not in a steady state during the acquisition. Two main research axis are presented in this thesis; the first one is a study of the impact of heart rate variation (described in the manuscript) on the transversal relaxation time T2 quantitative measurement. The study was lead on both phantom objects and on healthy volunteers. Two correction methods for heart rate variation are proposed, one based on the correction of the signal of the central line of the k-space, the other one based on a generalized reconstruction approach. First results are encouraging, and further works should be lead to confirm the methods efficacity. Then, heart rate variations are treated inside the cardiac cycle, and we propose a method to match the different segments of the electrocardiogram (ECG), based on the ECG deformation in the MR scanner probably due to by magnetohydrodynamic effect. This method is applied on imaging with a CINE kinetic sequence in which a better successive cardiac cycles segments matching should enable to improve image quality, at the condition to have sharp enough spatial and temporal resolutions. Results brought in this thesis are preliminary to necessary future researches in the sequence time domain, largely less addressed than organ motion

O disco intervertebral é uma estrutura cuja função é receber, amortecer e distribuir o impacto das cargas impostas sobre a coluna vertebral. O aumento da idade e a postura adotada pelo indivíduo podem levar à degeneração do disco intervertebral. Atualmente, a Ressonância Magnética (RM) é considerada o melhor e mais sensível método não invasivo de avaliação por imagem do disco intervertebral. Neste trabalho foram desenvolvidos métodos quantitativos computadorizados para auxílio ao diagnóstico da degeneração do disco intervertebral em imagens de ressonância magnética ponderadas em T2 da coluna lombar, de acordo com a escala de Pfirrmann, uma escala semi-quantitativa, com cinco graus de degeneração. Os algoritmos computacionais foram testados em um conjunto de dados que consiste de imagens de 300 discos, obtidos de 102 indivíduos, com diferentes graus de degeneração. Máscaras binárias de discos segmentados manualmente foram utilizadas para calcular seus centroides, visando criar um ponto de referência para possibilitar a extração de atributos. Uma análise de textura foi realizada utilizando a abordagem proposta por Haralick. Para caracterização de forma, também foram calculados os momentos invariantes definidos por Hu e os momentos centrais para cada disco. A classificação do grau de degeneração foi realizada utilizando uma rede neural artificial e o conjunto de atributos extraídos de cada disco. Uma taxa média de acerto na classificação de 87%, com erro padrão de 6,59% e uma área média sob a curva ROC (Receiver Operating Characteristic) de 0,92 indicam o potencial de aplicação dos algoritmos desenvolvidos como ferramenta de apoio ao diagnóstico da degeneração do disco intervertebral. / The intervertebral disc is a structure whose function is to receive, absorb and transmit the impact loads imposed on the spine. Increasing age and the posture adopted by the individual can lead to degeneration of the intervertebral disc. Currently, Magnetic Resonance Imaging (MRI) is considered the best and most sensitive noninvasive method to imaging evaluation of the intervertebral disc. In this work were developed methods for quantitative computer-aided diagnosis of the intervertebral disc degeneration in MRI T2 weighted images of the lumbar column according to Pfirrmann scale, a semi-quantitative scale with five degrees of degeneration. The algorithms were tested on a dataset of 300 images obtained from 102 subjects with varying degrees of degeneration. Binary masks manually segmented of the discs were used to calculate their centroids, to create a reference point to enable extraction of attributes. A texture analysis was performed using the approach proposed by Haralick. For the shape characterization, invariant moments defined by Hu and central moments were also calculated for each disc. The rating of the degree of degeneration was performed using an artificial neural network and the set of extracted attributes of each disk. An average rate of correct classification of 87%, with standard error 6.59% and an average area under the ROC curve (Receiver Operating Characteristic) of 0.92 indicates the potential application of the algorithms developed as a diagnostic support tool to the degeneration of the intervertebral disc.