Tato dizertační práce se zabývá modelováním mikrovlnných polovodičových struktur. Stále vyšší pracovní kmitočty komunikačních systémů zvyšují nároky na aktivní prvky a přenosová vedení, realizované zpravidla v monolitické integrované podobě. Přenosová vedení s rozprostřeným zesílením představují perspektivní řešení nejen jako zesilovací prvky, ale také jako aktivní napáječe mikrovlnných antén. V součastné době neexistuje vhodný softwarový nástroj pro jejich efektivní simulaci a návrh. První část této práce je zaměřena na implementaci termodynamické formulace modelu driftu a difuze pro numerickou simulaci transportních procesů polovodičových struktur v komerčním programu COMSOL Multiphysics. Další část je věnována implementaci Gunnova jevu v makroskopické aproximaci a vypracování simulační procedury pro analýzu struktur využívajících tento jev. Poslední část je věnována návrhu a analýze aktivních přenosových vedení a zlepšení jejich vlastností.

Mgr. Jiří Unger The utilization of 3D computer reconstruction visualizations in archaeology Abstract of dissertation thesis The visual presentation is in the field of archaeology one of the main communication media for conveying information and interpreting it. The recent introduction of digital technologies has brought a whole new dimension to archaeological visualisations. As a result of this development, they become three-dimensional, virtual, multifunctional and interactive. Technological development moreover has not only influenced the way how to retrieve and process the data, but greatly expanded as well the ability to simulate and visualize their different aspects in virtual environment. Since the beginning the virtual archaeology has been taken as direction that would bring new groundbreaking knowledge into the archaeology. However, the current situation is that 3D computer visualizations are just popular conference theme than a standard tool of archaeology as a science, and most works on virtual archaeology still needs to advocate the benefits of 3D visualizations. Therefore, the dissertation thesis try to deal with theoretical issues of preparation, organisation and analysis of input data in the process of creation of 3D reconstruction computer models, then with possible solutions of visualization...

This thesis discusses the process of modeling a 21,000 seat fan-shaped auditorium using methods of geometric acoustics. Two commercial geometric acoustics software packages were used in the research: CATT-Acoustic™ 8.0 and EASE™ 4.1. The process first included creating preliminary models of the hall using published absorption coefficients for its surfaces and approximate scattering coefficients based on current best-known techniques. A detailed analysis determined the minimum numbers of rays needed in both packages to produce reliable results with these coefficient values. It was found that 100,000 rays were needed for CATT™ and 500,000 rays were needed for EASE™. Analysis was also done to determine whether the model was sensitive to the scattering coefficients of the seating areas. It was found that most acoustic parameters were not significantly affected by scattering coefficient variation. The models were subsequently refined by including measured absorption coefficients of dominant surfaces in the hall: the seats, audience and suspended absorptive panels. Comparisons were made between measurements made in the hall and results from the computer models with impulse responses, acoustic parameters, and auralizations. The results have shown that the models have been successful at representing characteristics of the hall at some positions but less successful at representing them at other positions. Comparisons have shown that positions on the rostrum were especially difficult positions to model in this hall. Significant differences were not found between the preliminary models and the refined models. There was not significant evidence showing that either the EASE™ or the CATT™ model was more successful in accurately representing the acoustical conditions of the hall. The results from this research suggest that more work must be done to improve the modeling capabilities of these packages for this application.

No description available.

No description available.

Tesis por compendio / [ES] La ablación por radiofrecuencia (RF) se ha convertido en una técnica ablativa importante, ampliamente utilizada en el área de las terapias mínimamente invasivas de la medicina moderna. El avance en el campo de las tecnologías basadas en RF a lo largo de los años ha llevado a un número creciente de aplicaciones en diferentes áreas terapéuticas tales como arritmias cardíacas, epilepsia, oncología, resección asistida, apnea, dolor o cirugía estética. Sin embargo, existe una constante necesidad de desarrollar estudios computacionales y experimentales para mejorar el rendimiento de estas técnicas. El enfoque principal de esta tesis doctoral está centrado en examinar los efectos térmicos y eléctricos de ablación por radiofrecuencia de tejidos para mejorar la eficacia y la seguridad de las terapias y dispositivos basados en energía de radiofrecuencia. Las dos áreas principales de interés han sido el tratamiento del dolor y la cirugía hepática oncológica, que se han organizado en tres estudios independientes. La metodología de los estudios se ha basado en modelos computacionales y estudios experimentales sobre phantom de agar, modelos ex vivo e in vivo y ensayos clínicos. El estudio focalizado en el tratamiento del dolor ha incluido el análisis de los efectos eléctricos y térmicos del tratamiento con radiofrecuencia pulsada (PRF) y el riesgo relacionado con el daño térmico al tejido. Se han estudiado diferentes protocolos pulsados empleados en la práctica clínica utilizando modelos computacionales. La exactitud del modelo se ha validado mediante un modelo en phantom de agar. Se han propuesto también modelos computacionales adicionales para los protocolos pulsados alternativos en los cuales se reduciría el efecto térmico sin afectar al efecto eléctrico. En el estudio se ha discutido también el concepto de electroporación leve como el resultado de PRF. En el área de la cirugía hepática oncológica se han analizado dos técnicas diferentes. El primer estudio se ha centrado en examinar la hidratación del tejido durante la ablación por RF con un nuevo electrodo ICW. El nuevo diseño ha incluido dos agujas de perfusión expandibles integradas en el catéter. El objetivo principal ha sido mejorar la precisión del modelo computacional de ablación por RF de tumor utilizando una geometría realista de la distribución de solución salina en el tejido y evaluar el rendimiento del catéter de RF. Se han modelado diferentes casos de tumor infundido con solución salina y los resultados simulados se han comparado con los datos clínicos de un ensayo en 17 pacientes con cáncer hepático. Con el fin de obtener una distribución espacial realista de la solución salina infundida, se ha empleado un estudio in vivo sobre el modelo de hígado de cerdo. El segundo estudio se ha centrado en el desarrollo de una nueva técnica de sellado endoluminal basada en catéter, como una alternativa más efectiva para el manejo del remanente pancreático. El método ha consistido en una ablación por radiofrecuencia guiada por impedancia con la técnica de pullback. El ajuste del tipo de catéter de RF y del protocolo de ablación se ha realizado mediante modelos porcinos ex vivo. Posteriormente, la efectividad del sellado se ha evaluado sobre un modelo de cerdo in vivo. / [CA] L'ablació per radiofreqüència (RF) s'ha convertit en una tècnica ablativa important, àmpliament utilitzada en l'àrea de les teràpies mínimament invasives de la medicina moderna. L'avanç en el camp de les tecnologies basades en RF al llarg dels anys ha portat a un número creixent d'aplicacions en diferents àrees terapèutiques com ara arítmies cardíaques, epilèpsia, oncologia, resecció assistida, apnea, dolor o cirurgia estètica. No obstant això, hi ha una constant necessitat de desenvolupar estudis computacionals i experimentals per a millorar el rendiment d'aquestes tècniques. Aquesta tesi doctoral ha estat centrada en examinar els efectes tèrmics i elèctrics de l'ablació per radiofreqüència de teixits per tal de millorar l'eficàcia i la seguretat de les teràpies i dispositius basats en energia de radiofreqüència. Dos àrees principals són el tractament del dolor i la cirurgia hepàtica. Aquestos han sigut organitzats en tres estudis independents. La metodologia dels estudis ha estat basada en models computacionals i experimentals sobre phantom d'agar, models ex vivo i in vivo i assajos clínics. L'estudi enfocat en el tractament del dolor ha inclòs l'anàlisi dels efectes elèctrics i tèrmics del tractament amb radiofreqüència polsada (PRF) i el risc relacionat amb el dany tèrmic al teixit. S'han estudiat diferents protocols polsats emprats en la pràctica clínica utilitzant models computacionals. L'exactitud del model ha estat validada per mitjà d'un model de phantom d'agar. S'han proposat també models computacionals addicionals per a protocols polsats alternatius en els quals es reduiria l'efecte tèrmic sense afectar l'efecte elèctric. En aquest estudi s'ha discutit també el concepte d'electroporació lleu com el resultat de PRF. A l'àrea de la cirugía hepàtica han sigut analitzades dos tècniques diferents. El primer estudi s'ha centrat en la hidratació del teixit durant l'ablació per RF amb un nou elèctrode ICW. El nou disseny ha inclòs dos agulles de perfusió expandibles integrades en el catèter. L' objetiu principal ha sigut millorar la precisió del model computacional d' ablació de tumors per RF utilitzant una geometria realista per a la distribució de sèrum salií en el teixit i evaluar el rendiment del catèter de RF. S'han modelat diferents casos de tumor infundit amb sèrum salí i els resultats simulats han sigut comparats amb les dades clíniques d'un assaig dut a terme sobre 17 pacients amb càncer hepàtic. Amb l'objetiu d'obtenir una distribució espacial realista del sèrum salí injectat, s'ha du a terme un estudi in vivo basat en un model de fetge de porc. El segon estudi s'ha centrat en el desenvolupament d'una nova tècnica de tancament endoluminal bassat en catèter, com una alternativa més efectiva per a gestionar el romanent pancreàtic. El mètode ha consistit en una ablació per radiofreqüència guiada per impedància amb la tècnica de pullback. L'ajust del tipus de catèter de RF i del protocol d'ablació ha sigut realitzat per mitjà de models porcins ex vivo. Posteriorment, l'efectivitat del tancament ha sigut avaluada sobre un model de porc in vivo. / [EN] Radiofrequency (RF) ablation has become an important ablative technique widely used in the area of minimally invasive therapies of the modern medicine. The advancement in the field of RF-based technologies over the years has led to a growing number of applications in different therapeutic areas such as cardiac arrhythmias, epilepsy, oncology, assisted resection, apnea, pain or aesthetic surgery. There is, however, a constant need for the development of computer and experimental studies, which would enhance the performance and safety of these techniques. The main focus of this PhD Thesis was on examining the thermal and electrical phenomena behind tissue radiofrequency ablation in order to improve the efficacy and safety of the RF-based therapies and applicators. Two main areas of interest were pain management and oncology, which were organized into three independent studies. The research methodology was based on computer modeling and experimental studies on phantoms, ex vivo and in vivo models, and clinical trials. The research on pain management involved the analysis of electrical and thermal effects of the pulsed radiofrequency (PRF) treatment and the related risk of tissue thermal damage. Different pulse protocols used in clinical practice were studied using computer modeling and the study accuracy was validated by means of agar phantom model. Additional computer models for alternative pulse protocols were also proposed, in which thermal effect would be reduced but the electrical effect would remain unchanged. The study also discussed the concept of a mild electroporation from PRF. In the area of oncology, two different techniques were analyzed. First study focused on examining tissue hydration technique during RF ablation with a novel internally cooled wet (ICW) electrode. The new design involved two expandable perfusion needles built into the catheter. The main aim was to improve the accuracy of computer model of tumor RF ablation using a realistic geometry of saline distribution in tissue, and to assess the performance of the RF catheter. Different cases of saline-infused tumor were modeled and the simulated results were compared with the clinical data from a trial on 17 hepatic cancer patients. An in vivo study on pig liver model was used to obtain a realistic spatial distribution of the infused saline. The second study focused on the development of a new catheter-based endoluminal sealing technique as more effective alternative for management of the pancreatic stump. The method consisted of the impedance-guided radiofrequency ablation with pullback. Fine-tuning involving RF catheter type and ablation protocol was performed using ex vivo porcine models, and posteriorly, sealing effectiveness was assessed on an in vivo pig model. / The completion of this work would have not been possible without the financial support of the Spanish Ministerio de Economía, Industría y Competitividad that provided funding for the development of this research project, my Predoctoral scholarship, and also Travel Grant for the research stay in The Wellman Center for Photomedicine / Ewertowska, E. (2019). Computer modeling and experimentation in radiofrequiency-based minimally invasive therapies [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/134057 / Compendio

Le rôle des deux paires de bases universelles inverse Hoogsteen U : A ( RHUAs ) présentent chez les ARNt standards , une dans la boucle T et l'autre dans le noyau de la forme en L , a été étudiée. Pour chacun des RHUAs , un criblage génétique spécialisé in vivo chez les bactéries , le système suppresseur ambre ( pour l'étude de la RHUA dans la boucle T ) et le système d'ARNt de la sélénocystéine ( tRNASec ) ( pour l'étude de la RHUA dans le noyau ) , ont été utilisé pour générer des variants fonctionnels à partir de multiples librairies combinatoires . Ces variants ont ensuite été séquencé et soumis à une analyse systématique qui comprend la modélisation informatique et un type d'analyse phylogénétique. Les résultats du système suppresseur ambre ont montré un ensemble de variants fonctionnels qui ne nécessitent pas le motif RHUA dans la boucle T et qui ont remplacé la méthode standard de l'interaction entre les boucles D et T avec une double hélice interboucle , ILDH . D'autres études ont abouti à la détermination d'un modèle In silico de l'alternative à la norme standard de la boucle T, sous le nom de type III . Les résultats du système tRNASec ont révélé que pour cette ARNt exceptionnel, l'absence de RHUA ( dans le noyau ) assure une flexibilité accrue qui est spécifiquement nécessaire pour la fonction de tRNASec . Ainsi, les ARNt standards , à la différence de tRNASec , avec la présence universelle de RHUA dans le noyau , a été naturellement sélectionnée pour être rigide . Pris ensemble, la RHUA joue un rôle essentiel dans la stabilisation des interactions tertiaires. / The role of two universally present reverse Hoogsteen U:A base pairs (RHUAs) in the T-loop and in the core of the L-shape of standard tRNA was studied. To study each of the RHUAs, bacterial in vivo genetic screens were used including the amber suppressor system (for the study of the RHUA in the T-loop) and the selenocysteine tRNA(tRNASec) system (for the study of the RHUA in the core). These screens generated functional variants from multiple combinatorial libraries. These variants were subsequently sequenced and subjected to a systematic analysis which included computer modeling and a type of phylogenetic analysis. The results from the amber suppressor system showed a set of functional variants which did not require the RHUA motif in the T-loop, and had replaced the standard way of interaction between the D and T loops with an interloop double helix, ILDH. Further study culminated in the determination of an insilico model of the alternative to the standard T-loop known as type III. The results from the tRNASec system revealed that for this exceptional tRNA, the absence of RHUA (in the core) ensures an enhanced flexibility that is specifically required for tRNASec function. Thus standard tRNAs, unlike tRNASec, with the universal presence of RHUA in the core have been naturally selected to be rigid. Taken together, RHUA plays an essential role in the stabilization of tertiary interactions.

Para melhorar a visualização das pequenas estruturas anatômicas importantes para o diagnóstico do câncer de mama e otimizar o processamento das mamografias pelos sistemas computadorizados de auxílio ao diagnóstico (CAD), foi desenvolvido um dispositivo, baseado na tecnologia slit, que melhora a aquisição dos mamogramas. Este dispositivo reduz a radiação espalhada e o tamanho do foco e foi projetado a partir de um modelo computacional. O modelo adotado permite quantificar o valor desses parâmetros para qualquer sistema radiológico, qualquer espessura de tecidos moles radiografada e qualquer tensão aplicada ao tubo de raios-X. O dispositivo foi implementado e testado, quantificando as melhorias obtidas. As imagens geradas foram comparadas com as fornecidas pelos sistemas mamográficos convencionais. O modelo serviu para estudar também a interferência do espalhamento sobre o desempenho dos algoritmos usados nos sistemas de diagnóstico auxiliado por computador (CAD). / In order to improve the visualization of the small and important anatomical structures for breast cancer diagnosis and to optimize the image processing of mammograms by the computer aided diagnosis systems (CAD), a device that comes from slit technology was developed to improve the acquisition of mammograms. This device reduces the amount of scattered radiation and the focus size and it can be projected from a computational model. This model allows quantifying the value of those parameters, scattered radiation and the focus size, for any radiological system, any X-rayed soft tissue thickness and any tension applied to the X-ray tube. The device was implemented and tested quantifying the obtained improvements. The generated images were compared to the supplied for conventional mammography systems. The model was also good for studying interference on the algorithms used in the computer aided diagnosis systems (CAD).

<p>Neuropeptide Y (NPY) is known to influence a vast number of physiological and behavioral processes such as vasoconstriction, circadian rhythms, feeding, anxiety and memory. Peptides of the NPY family bind to five different cloned G-protein coupled receptor subtypes (Y1, 2, 4-6). The studies compiled in this thesis present inter-species comparisons of sequence similarities, binding properties and expression patterns among receptors of the NPY family.</p><p>Cloning of Y1 and Y2 receptor subtypes from guinea pigs revealed strong binding profile similarity to the corresponding human receptors. Previously demonstrated atypical binding profiles in the caval vein of guinea pigs were concluded to result from other receptors than the cloned Y1 and Y2 receptors, or possibly combinations of distinct receptor subtypes.</p><p>The guinea pig Y5 receptor was found to be expressed in regions of the brain that have been indicated as important for regulation of food intake. Expression in the hypothalamus, amygdala and brain stem was noticed, similar to studies in rats and humans. In other brain regions, such as the striatum and hippocampus, some species differences were observed.</p><p>Mutagenesis studies of the human Y1 receptor indicated sites important for binding both of endogenous agonists and synthetic antagonists. Putative new sites of interaction with the Y1 antagonists BIBP3226 and/or SR120819A were recognized. The data were used to construct a three-dimensional structure model, based on a high-resolution bovine rhodopsin model.</p><p>Cloning of the chicken (<i>Gallus gallus</i>) Y1, Y2 and Y5 receptors revealed high sequence similarities with mammalian receptors. Most endogenous ligands bound with similar affinities as to mammalian receptors. The strongest exception was the discovery of high-affinity binding to chicken Y2 of [Leu³¹, Pro³⁴]NPY, which was previously considered to bind non-Y2 receptors only. </p><p>The new human Y1 receptor model provides a basis for further investigations of ligand-receptor interactions which will be aided by information on NPY receptors from other taxa. Guinea pigs are concluded to be a good complement to rats and mice for studying NPY signaling. These results demonstrate the benefits of species comparisons for pharmacological studies.</p>

Neuropeptide Y (NPY) is known to influence a vast number of physiological and behavioral processes such as vasoconstriction, circadian rhythms, feeding, anxiety and memory. Peptides of the NPY family bind to five different cloned G-protein coupled receptor subtypes (Y1, 2, 4-6). The studies compiled in this thesis present inter-species comparisons of sequence similarities, binding properties and expression patterns among receptors of the NPY family. Cloning of Y1 and Y2 receptor subtypes from guinea pigs revealed strong binding profile similarity to the corresponding human receptors. Previously demonstrated atypical binding profiles in the caval vein of guinea pigs were concluded to result from other receptors than the cloned Y1 and Y2 receptors, or possibly combinations of distinct receptor subtypes. The guinea pig Y5 receptor was found to be expressed in regions of the brain that have been indicated as important for regulation of food intake. Expression in the hypothalamus, amygdala and brain stem was noticed, similar to studies in rats and humans. In other brain regions, such as the striatum and hippocampus, some species differences were observed. Mutagenesis studies of the human Y1 receptor indicated sites important for binding both of endogenous agonists and synthetic antagonists. Putative new sites of interaction with the Y1 antagonists BIBP3226 and/or SR120819A were recognized. The data were used to construct a three-dimensional structure model, based on a high-resolution bovine rhodopsin model. Cloning of the chicken (Gallus gallus) Y1, Y2 and Y5 receptors revealed high sequence similarities with mammalian receptors. Most endogenous ligands bound with similar affinities as to mammalian receptors. The strongest exception was the discovery of high-affinity binding to chicken Y2 of [Leu31, Pro34]NPY, which was previously considered to bind non-Y2 receptors only. The new human Y1 receptor model provides a basis for further investigations of ligand-receptor interactions which will be aided by information on NPY receptors from other taxa. Guinea pigs are concluded to be a good complement to rats and mice for studying NPY signaling. These results demonstrate the benefits of species comparisons for pharmacological studies.