Trabalhos anteriores sobre a síntese de imagens de difusão por ressonância magnética se limitaram a estudos sobre estruturas microscópicas, menores que as dimensões típicas de um voxel (e.g., [BF08] [BF13] [LFS + 10] e [BA94]). Isto decorre em parte devido às metodologias utilizadas, que têm como ponto em comum serem simulações de tipo Monte Carlo, nas quais os elementos mínimos da simulação são as partículas de água. Portanto o custo computacional destas simulações é proporcional ao número de partículas a simular, e isto limita os volumes que podem ser simulados a tamanhos microscópicos. Propomos uma metodologia alternativa, que utiliza a imagem T 2 de uma amostra para sintetizar imagens de difusão por ressonância magnética. Os elementos mínimos desta nova metodologia são os pontos da imagem T 2 , e portanto seu custo computacional é proporcional à resolução da imagem T 2 utilizada, o que permite a síntese a partir de amostras de qualquer tamanho físico. Estas sínteses são realizadas por meio da integração numérica da equação do artigo seminal de Stejskal e Tanner [ST65] que relaciona a atenuação do sinal de ressonância magnética devida à difusão com os parâmetros da sequência de pulsos PGSE. Usamos os parâmetros típicos dessa sequência (b, gamma, tau\', g 0, g, delta e Delta), que podem ser configurados explicitamente em máquinas de ressonância magnética, para calcular valores do coeficiente de difusão aparente D em direções arbitrárias. Desenvolvemos software, disponibilizado [Bor] por licença GPL [Fou07], para realizar estas simulações, e para especificar uma máscara de direções, útil para modelar a difusão de uma amostra. Estas ferramentas permitem o estudo sistemático das variações dos parâmetros na síntese de imagens de difusão por ressonância magnética. Apresentamos um estudo de um fantoma de capilares imersos em água, exemplificando como utilizar as ferramentas para investigar a influência destes parâmetros na difusão da água da amostra. / Previous work on the synthesis of diffusion-weighted magnetic resonance imaging are limited to microscopic structures, smaller than the typical dimensions of a single voxel (e.g., [BF08] [BF13] [LFS + 10] and [BA94]). This is consequence, in part, of the methodologies used, that have in common the adoption of Monte Carlo simulation strategies, in which the minimal elements of simulation are the water particles. Therefore the computational cost of these simulations is proportional to the number of particles to simulate, and this limits the volume to be simulated to microscopic sizes. We propose a novel methodology, that uses the T 2 image from a sample to synthesize diffusion-weighted magnetic resonance images. The mininal elements of this novel methodology are the points of the T 2 image, and therefore its computational cost is proportional to the resolution of the T 2 image to be used, which allows the synthesis from samples of any physical size. These syntheses are made through numerical integration of the equation from the seminal article by Stejskal and Tanner [ST65] that relates the attenuation of the magnetic resonance signal due to diffusion to the parameters of the PGSE pulse sequence. We use the typical parameters of this sequence (b, gamma, tau\', g 0, g, delta and Delta), that can be explicitly configured in magnetic resonance machines, to calculate apparent diffusion coefficients D in arbitrary directions. We developed software, available [Bor] through GPL license [Fou07], to run these simulations, and to specify a mask of directions useful to model diffusion. These tools allow the systematic study of parameter variation in the synthesis of diffusion-weighted magnetic resonance images. We present a case study of a phantom made of capillary tubes immersed in water, to exemplify the use of these tools and how to investigate the influence of parameter variation on diffusion in the sample.

This diploma thesis deals with a basic description of dynamic and condenser microphone, its performance regarding polar patterns and a type of mechanical construction. It also describes a principle of operation of a triode. The thesis deals with selecting of a suitable type of microprocessor to control microphone preamplifier functions. Last part contains a power supply and microphone preamplifier circuits design using a semiconductor and vacuum tube technology.

This master’s thesis deals with user influence on miniature antennas in mobile application. Electrically small antennas including fundamental performance properties and limitations are introduced in the theoretical section of this thesis. This section also deals with microstrip antennas and their common types. The accent is on PIFA antennas, their typical constructions and methods of miniaturization. In the practical section, dual-band PIFA antenna for operation at frequencies of systems GSM900 and GSM1800 is designed with the assistance of electromagnetic field simulator CST Microwave Studio. On this type of antenna, the user influence on impedance matching and radiation pattern in data mode (the user is typing message or browsing with the phone) is investigated. For this purpose the hand phantom, corresponding to author’s right hand, was made from agar based material. For typical position of human hand is designed matching network, which eliminate the user influence and ensure correct function of antenna.

This thesis deals with optimization of MRI measuring of phantoms containing the chicken embryo. The theoretical part of thesis is dedicated to the MRI fundamentals and description of pulse sequences. In the next part the options of keeping and monitoring the temperature are being discussed. The thesis also deals with design and realization of phantoms which are used for measuring. A browser of images captured by MRI was programmed in Matlab environment. The program allows users to look through the images with different settings of pulses sequences or kind of phantom. The final part of thesis describes the anatomical structures of chicken embryo and discussion of collected results.

[ES] La cápsula inalámbrica de endoscopia (WCE) es una tecnología notable y atractiva adoptada en el sector biomédico hace varios años. WCE proporciona una tecnología de imagen inalámbrica no invasiva que permite a los especialistas reconocer y diagnosticar enfermedades que afectan todo el tracto gastrointestinal. Aunque los médicos pueden recibir imágenes claras de anomalías en el tracto gastrointestinal, no tienen información sobre sus exacta ubicación. La localización precisa de los trastornos detectados es crucial para el posterior procedimiento de extracción mediante cirugía. Actualmente, la banda de frecuencia asignada para aplicaciones de cápsula endoscópica es la banda MICS (402-405 MHz) que ofrece una velocidad de datos de hasta 500 kbps, insuciente para transmitir imágenes de alta calidad. Recientemente, la tecnología de banda ultra ancha (UWB) ha estado atrayendo atención como posible candidato para la próxima generación de cápsula endoscópica. Las ventajas de UWB incluyen arquitecturas de transceptor simples que permiten bajo consumo de potencia, baja interferencia a otros sistemas y amplio ancho de banda que resulta en comunicaciones a una velocidad de datos más alta. En esta disertación, el rendimiento de las técnicas de localización de WCE basadas en radiofrecuencia (RF) se investiga a través de simulaciones software, medidas experimentales de laboratorio que involucran fantomas homogéneos y heterogéneos y a través de experimentos in vivo que constituyen el escenario de prueba más realista. La tecnología UWB (3.1-10.6 GHz) se considera como interfaz de comunicación para aplicaciones de cápsula endoscópica. En tal escenario, el transmisor inalámbrico está ubicado en el tracto gastrointestinal, mientras que uno o más receptores inalámbricos están ubicados sobre la supercie del cuerpo. El enfoque basado en la potencia recibida (RSS) se investiga principalmente debido a su simplicidad de implementación y menos sensibilidad a las limitaciones de ancho de banda. Se analiza el impacto de la posición y del número de receptores seleccionados en la precisión de la localización. Finalmente, se desarrolla una interfaz gráfica de usuario (GUI) para visualizar los resultados de la localización en tres dimensiones (3D) obtenidos mediante las medidas in vivo. / [CAT] La càpsula sense fil d'endoscòpia (WCE) és una tecnologia notable i atractiva adoptada en el sector biomèdic fa diversos anys. La WCE proporciona una tecnologia d'imatge sense fil no invasiva que permet als especialistes reconéixer i diagnosticar malalties que afecten tot el tracte gastrointestinal. Encara que els metges poden rebre imatges clares d'anomalies en el tracte gastrointestinal, no tenen informació sobre les seues exacta ubicació. La localització precisa dels trastorns detectats és crucial per al posterior procediment d'extracció mitjançant cirurgia. Actualment, la banda de freqüència assignada per a aplicacions de càpsula endoscòpica és la banda MICS (402-405 MHz) que ofereix una velocitat de dades de fins a 500 kbps, insucient per a transmetre imatges d'alta qualitat. Recentment, la tecnologia de banda ultra ampla (UWB) ha estat atraient atenció com a possible candidata per a la pròxima generació de càpsula endoscòpica. Els avantatges d' UWB inclouen arquitectures de transceptor simples que permeten un baix consum de potència, baixa interferència amb altres sistemes i una gran amplada de banda que resulta en comunicacions a una velocitat de dades més alta. En aquesta dissertació, el rendiment de les tècniques de localització de WCE basades en radiofrequència (RF) s'investiga a través de simulacions amb programari, mesures experimentals de laboratori que involucren fantomes homogenis i heterogenis i a través d'experiments in vivo que constitueixen l'escenari de prova més realista. La tecnologia UWB (3.1-10.6 GHz) es considera com a interfície de comunicació per a aplicacions de càpsula endoscòpica. En tal escenari, el transmissor sense fil està situat en el tracte gastrointestinal, mentre que un o més receptors sense fils estan situats sobre la superfície del cos. L'enfocament basat en la potència rebuda (RSS) s'investiga principalment a causa de la seua simplicitat d'implementació i menys sensibilitat a les limitacions d'amplada de banda. S'analitza l'impacte de la posició i del numere de receptors seleccionats en la precisió de la localització. Finalment, es desenvolupa una interfície gràca d'usuari (GUI) per a visualitzar els resultats de la localització en tres dimensions (3D) obtinguts mitjançant les mesures in vivo. / [EN] Wireless Capsule Endoscopy (WCE) is a remarkable and attractive technology adopted in the biomedical sector several years ago. It provides a non-invasive wireless imaging technology for the entire gastrointestinal (GI) tract. WCE allows specialists to recognize and diagnose diseases affecting the whole GI tract. Although physicians can receive clear pictures of abnormalities in the GI tract, they have no information about their exact location. Precise localization of the detected disorders is crucial for the subsequent removal procedure by surgery. Currently, the frequency band allocated for capsule endoscopy applications is the MICS band (402-405 MHz). This band offers data rate up to 500 kbps, which is insufficient to transmit high quality images. Recently, Ultrawideband (UWB) technology has been attracting attention as potential candidate for next-generation WCE systems. The advantages of UWB include simple transceiver architectures enabling low power consumption, low interference to other systems and wide bandwidth resulting in communications at higher data rate. In this dissertation, performance of WCE localization techniques based on Radio Frequency (RF) information are investigated through software simulations, experimental laboratory measurements involving homogeneous and heterogeneous phantom models and in vivo experiments which constitute the most realistic testing scenario. Ultra-Wideband technology (3.1-10.6 GHz) is considered as communication interface in Wireless Capsule Endoscopy. In such scenario, the wireless transmitter is located in the gastrointestinal track while one or more wireless receivers are located over the surface of the body. Received Signal Strength (RSS)-based approach is mainly explored due to its implementation simplicity and less sensitivity to bandwidth limitations. Impact of the position and the number of selected receivers on the localization accuracy is analyzed. Finally, a graphical user interface (GUI) is developed to visualize the three-dimensional (3D) localization results obtained through in vivo measurements. / Barbi, M. (2019). Location and Tracking for Ultra-WideBand In-Body Communications in Medical Applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/132874 / TESIS

The dissertation introduces the art performance by Miroslav Hornicek. It reflects the collage creation which Miroslav Hornicek devoted more than twenty years. The author introduced the gift of improvisation and humor into his collage. Many of them look like graphic, some of them remind the theater scene. He often repeats the same motive such as eye, sisters, theatrical costumes, sculptures, senses and body organs. It is interesting that despite his work he did not consider himself like the artist. He created many collage, he found inspiration in the creation of Max Ernst, Toyen, Jindrich Styrsky and Jiri Kolar. In relating with Jiri Kolar it is possible to search a certain similarity. From the poet became the artist, collage maker. Miroslav Hornicek was primarily the actor who has also found a way of life in creating collages. Miroslav Hornicek wrote to some of his collages names and interpretations. This material is very important for trying to understand his theater scenes and a tangle of something "incomprehensible", because of collages effect on the viewer. Finally, the dissertation aims to look at his art creation as a whole, highlight the exhibition activity and introduce Miroslav Hornicek not only as the actor, writer, dramatist, director and also the artist with an incredible imagination...

[pt] O presente trabalho teve como objetivo introduzir o pensamento de Nicolas Abraham e Maria Torok a partir de três eixos principais de sua conceitualização: o símbolo, a cripta e o fantasma. Através da abordagem desses conceitos, pretendeu-se investigar a compreensão dos autores sobre as ressonâncias do trauma na vida do sujeito e através das sucessivas gerações. / [en] The present study aimed to introduce the work of Nicolas Abraham and Maria Torok through three main ideas of their conceptualization: the symbol, the crypt and the phantom. By presenting these concepts, this paper tried to investigate the way those authors understood the effects of traumatic experiences on the individual s life and through generations.

The objective of this preliminary study was to determine the potential of diffuse correlation spectroscopy (DCS) for assessment of coagulation depth. Coagulation of tissue can occur due to a number of different reasons such as thermal or electrical burns or radiofrequency ablation. DCS is a non-invasive optical technique which can be used to determine the optical and dynamic properties of tissue by fitting a theoretical model of photon propagation in multiply scattering tissue to experimental data obtained from measurements. The DCS measurements were performed on two-layered phantom models that represent healthy tissue with high flow properties with a layer of coagulated tissue with low flow properties on top. Three different phantom models were prepared using gelatin-Intralipid gels, PDMS, and nylon as an upper layer, and an Intralipid solution was used for the bottom layer for all three phantoms. DCS measurements were performed on all three phantom models with varying thicknesses of the upper layers, and varying source-detector separations. The acquired data from the DCS measurement were analyzed in MATLAB in order to obtain the electric field temporal autocorrelation function. A theoretical model describing photon propagation in a two-layered medium was fitted to the obtained data in order to extract the desired parameters. The results showed that the thickness of the gelatin-Intralipid gels could be extracted within a 0.5 mm certainty and the thickness of the PDMS phantoms could also be extracted within approximately 0.7 mm. For the nylon phantoms, the results obtained were not good because the fitting was not successful and the thickness was not extracted appropriately. There is potential in DCS for assessment of burn wound depth but further research and development has to be done in the field in order to obtain more accurate and reliable results.

Cardiovascular diseases (CVD) remain one of the leading causes of deaths worldwide. The formation and presence of aneurysm is a very important question in the study of this CVDs. An aneurysm is a balloon-like bulge on a blood vessel which forms over time. An aneurysm is usually considered to be a result of weakening of the blood vessel walls, this definition has stood over many years without being conclusively proven. Eventually, the aneurysm could clot or burst due to degradation of the aneurysm wall and accumulation of blood. The latter would lead to internal bleeding and result in a stroke. Local hemodynamics have been found to be very important in the study of the evolution of an aneurysm. In this study, a steady flow experimental investigation was conducted using planar Particle Image Velocimetery (PIV) on a rigid flow phantom of an idealised geometry consisting of a curve parent artery and a spherical aneurysm located on the outer convex side of the curvature. The flow phantom was fabricated directly using a commercially available desktop Stereolithography (STL) 3D printer instead of the more conventional investment casting method using a core. Although 3D printing technologies have been around for many years, the fabrication of flow phantoms by direct printing is still largely under-explored. This thesis details the results of investigation into the optimal printing and post-printing procedures required to produce a flow phantom of suitable clarity and transparency. Other important areas of concern such as the geometric accuracy, surface topography and refractive index of the final model are also investigated. A planar PIV is conducted to study the impact of flow rates on the local flow field in and around the aneurysm and their impact on the wall shear stress. It was found that direct 3D printing is appropriate for the fabrication of flow phantoms suitable for PIV or other flow visualisation techniques. It reduces the complexities and time needed compared to the conventional investment casting methods. It was observed that the optical properties of the printed material such as the high refractive index (RI) and the transmittivity of light could cause a problem in large models. From the PIV measurements it was found that flow rates affect the flow field in both the parent artery and the aneurysm. First, high velocities were observed on the outer curvature of the parent artery. Secondly the centre of rotation in the aneurysm is not at the geometric centre but is displaced slightly in the direction of the flow. Finally, the flow rate affects the angle in which flow enters the aneurysm from the parent vessel. This change in the flow angle affects the flow within the aneurysm. A higher flow rate in the parent artery increases the incident angle which brings the centre of rotation closer to the geometric centre of the aneurysm, this changes the location and magnitude of high velocities and hence the local wall shear stress (WSS) on the wall of the aneurysm. This may have implications in the evolution of aneurysms. / Mechanical and Industrial Engineering

Le travail présenté dans ce manuscrit concerne la fabrication de fantômes d'aorte patient spécifiques utilisant une technique de fabrication additive par impression 3D. Ces répliques sont fabriquées en matériaux synthétiques dont les caractéristiques morphologiques et les propriétés mécaniques doivent être proches de celles déterminées sur un patient. Elles permettent d'optimiser ou de développer les techniques d'imagerie médicale, de comprendre les relations entre le comportement mécanique de la paroi aortique et les caractéristiques hémodynamiques du flux sanguin mais aussi de réaliser des entrainements préopératoires aux interventions chirurgicales, telles que le traitement endovasculaire. Dans cette étude, le comportement mécanique hyper-viscoélastique de la paroi aortique est modélisé par un modèle de Maxwell solide généralisé, dont les paramètres ont permis la sélection et le développement de matériaux élastomères de type silicone aux comportements mécaniques contrôlés. Ces matériaux ont été élaborés à partir de mélanges de formulations existantes et des lois de mélange ont été comparées pour guider la définition de la composition idéale permettant d'imiter le comportement mécanique désiré. Nous avons mis au point une méthode basée sur l'imagerie médicale par ultrason, capable d'identifier les paramètres hyper-viscoélastiques d'une paroi vasculaire. Cette méthode a été validée sur des tubes réalisés avec ces formulations de silicone, dont les propriétés mécaniques ont été mesurées avec des méthodes de référence. Puis, ces silicones ont été utilisés dans un processus de fabrication additive utilisant l'impression 3D par voie indirecte. Un travail de conception assistée par ordinateur a été réalisé pour produire un fantôme d'aorte patient-spécifique présentant un anévrisme fusiforme et non-thrombosé dans la région thoracique / The present work deals with the producing of patient-specific aortic phantoms using an additive manufacturing technique by 3D printing. Phantoms are manufactured from synthetic materials with morphological and mechanical characteristics which should be close to these identified on a patient. They can be used to develop techniques of medical imaging, to understand the relationship between aortic mechanical behavior and hemodynamic properties of blood flow, as well as to perform a preoperative training of interventions, such as endovascular treatment. In this study, the hyper-viscoelastic aortic mechanical behavior was described using a generalized solid Maxwell model. Silicone materials were developed based on the model’s mechanical parameters to mimic various aortic mechanical behaviors. These materials were formulated from commercials silicones, and then mixing rules were compared to define the ideal mixture which can mimic the specific mechanical behavior. A nondestructive method based on medical imaging by ultrasound was developed to identify the parameters of a blood vessel hyper-viscoelastic model. Silicone tubes made of our formulations with known reference mechanical parameters, were used to validate this method. Then, these silicone materials were used in an additive manufacturing process using indirect 3D printing. A work of computer aided design was done to produce a patient-specific aortic phantom with a thoracic fusiform aneurysm without thrombosis