Dissertations / Theses on the topic 'PET'
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Abou-Kandil, Ahmed Ibrahim. "Development of microstructure in uniaxially drawn PET, PEN and 50% PET/PEN." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619759.
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Ryusuke, Nakamoto. "Comparison of PET/CT with sequential PET/MRI using an MR-compatible mobile PET system." Kyoto University, 2018. http://hdl.handle.net/2433/232099.
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Corazza, Martina. "Innovazione nella Diagnostica per Immagini: l’integrazione PET/RMN." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11618/.
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Nell'ambito della Diagnostica per Immagini, l'imaging ibrido sta assumendo un ruolo fondamentale in molte applicazioni cliniche, tra cui oncologia, neurologia e cardiologia. La possibilità di integrare informazioni complementari, funzionali e morfologiche, in un'unica immagine, permette di valutare con estrema accuratezza varie tipologie di malattie, diminuendo i tempi di acquisizione e i disagi per i pazienti. La risonanza magnetica, in sostituzione alla TAC nel sistema integrato PET/TC, introduce notevoli vantaggi quali l'acquisizione simultanea dei dati, l'ottimo contrasto dei tessuti molli, l'assenza di radiazioni ionizzanti e la correzione degli artefatti da movimento; ciò migliora l'accuratezza delle immagini e, di conseguenza, il processo diagnostico. Nonostante sia un interessante strumento di diagnostica e l'apice dello sviluppo tecnologico in imaging nucleare, vi sono alcune problematiche che ne impediscono la diffusa adozione, tra cui le interferenze reciproche tra le due modalità, i costi elevati e ancora una ridotta pubblicazione di articoli al riguardo.
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Rosa, Alessandro. "Caratteristiche dei radiofarmaci utilizzati per le indagini PET." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13260/.
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I radiofarmaci sono radionuclidi o composti chimici contenenti radionuclidi. Questi preparati radioattivi rispettano tutte le normative previste dalla farmacopea ufficiale (F.U.) per la somministrazione nell'uomo. Un rilevante numero di radiofarmaci sono da tempo utilizzati a scopo diagnostico e terapeutico nei reparti di medicina nucleare.L’avvento della tomografia ad emissione di positroni (PET), tecnica diagnostica per le immagini che fornisce informazioni di tipo funzionale-metabolica attraverso l’utilizzo di radionuclidi con breve emivita, ha incrementato la produzione di radionuclidi.Nel presente elaborato di tesi sono state analizzate le caratteristiche e il relativo campo di applicazione dei principali radiofarmaci utilizzati per le indagini PET. Per ognuno di essi è stato descritto il meccanismo d’azione e i principali utilizzi. I principali campi d’applicazione trattati sono quello Oncologico, Cardiologico e Neurologico. Oltre alle caratteristiche dei vari radiofarmaci sono state evidenziate anche le normative riguardanti le norme di buona preparazione dei radiofarmaci e i principali metodi di protezione dalle radiazioni.
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Martel, Bernuy Gianella Darlen, Niquen Dario Massa, Chávez Fiorella Francesca Olcese, and Vizarreta Alison Gloria Ramirez. "Safe Pet." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/655746.
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Este trabajo de investigación nace por el amor a nuestras mascotas, el querer darles una mejor calidad de vida y la necesidad que tenemos los dueños de mascotas de tener una atención inmediata y de calidad para nuestros amigos peludos cuando pase alguna emergencia. De esa necesidad es que nace el seguro para mascotas SAFE PET, que ofrece un paquete estándar que incluyan varios beneficios y coberturas para las mascotas afiliadas.
La principal fuente de ingreso de SAFE PET será la venta de nuestras pólizas, nuestra inversión inicial será de s/ 124,890 que la financiaremos el 60% los 4 socios de la empresa y 40% con un préstamo a una entidad financiera.
Por las investigaciones que realizamos mediante encuestas a dueños de mascotas, estos en su mayoría nos manifestaba el querer tener un seguro para su mascota, y luego gracias nuestra landing page pudimos observar que del 100% de visitas a nuestra landing el 54.6% dejó sus datos porque le interesa nuestro seguro, este porcentaje es mucho mayor al que esperábamos y eso nos alienta mucho más a ser uno de los primero en el país en dedicarnos exclusivamente en seguro integral de mascotas.
Finalmente, luego del estudio financiero realizado a nuestra empresa hemos considerado en el análisis de sensibilidad COK (89.71%) y un costo promedio ponderado de capital de WACC (74.53%), para terminar después de todo nuestro plan financiero podemos concluir que SAFE PET, es una empresa viable económicamente.This research was born for our love to pets and we want to give them a better life quality and the need that pet owners to have immediate and quality care for our furry friends when an emergency happens. From that need is born SAFE PET, that is a pet insurance, which offers a standard package that includes many benefits and coverages for affiliated pets. The main source of income for SAFE PET will be the sale of our policies, our initial investment will be S/ 124,890 which will be financed by 60% the 4 partners of the company and 40% with a loan to a financial institution. Due to the research we conducted through surveys of pet owners, most of them told us that they wanted to have insurance for their pet, and then thanks to our landing page we could observe that of 100% of visits to our landing, 54.6% left their data Because you are interested in our insurance, that percentage is much higher than we expected and that encourages us much more to be one of the first in the country to dedicate ourselves exclusively to comprehensive pet insurance. Finally, after the financial study carried out on our company, we have considered in the sensitivity analysis COK (89.71%) and a weighted average cost of capital of WACC (74.53%), to finish after all our financial plan we can conclude that SAFE PET, it is an economically viable company.
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Leon, Gómez Gabriela, Zegarra Speedy Jason Gomez, Arellano Kiara Yolanda Gutierrez, Grados Laura Viviana Olaya, and Huyhua Ricardo Augusto Toralba. "Pet Safe." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2019. http://hdl.handle.net/10757/653907.
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El presente trabajo plantea la puesta en marcha de un negocio innovador, para ello, se ha considerado los factores externos e internos que podrían repercutir en el desarrollo del mismo. Asimismo, se ha evaluado el contexto actual y se ha elaborado el respectivo estudio que sustenta la viabilidad del proyecto.
Hoy en día las personas se preocupan más por la seguridad de sus mascotas, existe una tendencia petfriendly que ha llevado a la sociedad a incrementar el consumo de alimentos balanceados, gastos en veterinarias y spas caninos.
Considerando que no existe en la actualidad un negocio similar al planteado, los alumnos autores del presente trabajo han considerado que la creación de un seguro para mascotas en el Perú sería altamente rentable.
Para sustentar la idea expuesta, se ha tomado en consideración todos los aspectos concernientes a la creación de la persona jurídica, los objetivos estratégicos, políticas internas y externas, análisis financieros y la rentabilidad del proyecto.
Después de analizar los aspectos antes mencionados, y de considerar todos los aspectos que puedan influir en su desarrollo, se llega a la conclusión de que el negocio es viable.This work proposes the start-up of an innovative business, for this, the external and internal factors that could have an impact on its development have been considered. Likewise, the current context has been evaluated and the respective study that supports the viability of the project has been prepared. Nowadays people care more about the safety of their pets, there is a petfriendly trend that has led society to increase consumption of feed, veterinary expenses and canine spas. Considering that there is currently no business similar to that proposed, the student authors of the present work have considered that the creation of pet insurance in Peru would be highly profitable. To support the idea presented, all aspects concerning the creation of the legal entity, strategic objectives, internal and external policies, financial analysis and the profitability of the project have been taken into consideration. After analyzing the aforementioned aspects, and considering all aspects that may influence its development, it is concluded that the business is viable.
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Cerrutti, Depaz Giannina Melitza, Huerta Nadya Fernández, Ortega Arturo Alejandro Salazar, and Cabrejos Mario Augusto Troya. "Pet Go." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2018. http://hdl.handle.net/10757/624821.
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Las mascotas tienen una influencia positiva en la salud y el bienestar de los seres humanos, por lo que hoy ocupan un lugar muy importante en los hogares de las familias, son considerados como un miembro más en la familia, independientemente del estrato cultural. Esta relación implica preocupación, temor entre otros riesgos que no solo causan tristeza en la familia, sino también en la misma mascota que sufre y pone en riesgo su salud que es necesario minimizar; aquí es donde nuestra idea contribuye a crear una identidad para las mascotas, a través de una placa con un código QR, que ofrece beneficios especialmente dirigidos a mejorar el cuidado de las mascotas y en caso de pérdida poder regresar a casa. Asimismo, contribuye a fortalecer la tenencia responsable de mascotas en los hogares de familia. Es necesario que el dueño conozca que en una era de constante crecimiento tecnológico puede llegar a tener un impacto positivo para la protección y beneficios a sus mascotas.Pets have a positive influence on the health and well-being of human beings, so today they occupy a very important place in the homes of families, they are considered as one more member in the family, regardless of the cultural stratum. This relationship implies concern, fear among other risks that not only cause sadness in the family, but also in the same pet that suffers and puts their health at risk that it is necessary to minimize; This is where our idea contributes to create an identity for pets, through a plate with a QR code, which offers benefits especially aimed at improving the care of pets and in case of loss to be able to return home. It also contributes to strengthening responsible pet ownership in family homes. It is necessary that the owner knows that in an era of constant technological growth can have a positive impact for the protection and benefits to their pets
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Chonde, Daniel B. "Improved PET Data Quantification in Simultaneous PET/MR Neuroimaging." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:17467219.
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Recently, systems that integrate positron emission tomography and magnetic resonance imaging (PET/MR) have become available for clinical use. This new technology, which combines the high spatial resolution and superior soft-tissue contrast of MR with the picomolar sensitivity, quantitative capabilities, and wide array of tracers of PET, has the potential to benefit patients and provide insights that were previously unattainable in standalone systems. Simultaneous measurement of PET and MR parameters provides complementary information, allowing for a more complete assessment of disease, as well as cross validation and calibration of MR and PET measurements and techniques.
To take full advantage of such a multi-modal system, accurate quantification of the PET data is necessary. Due to the low spatial resolution of PET – which can be further reduced by external factors like patient motion – and the inherent lack of anatomic detail, accurate quantification can be challenging. The simultaneously acquired MR information provides an opportunity to optimize PET quantification and analysis. In order to fully realize the benefits provided by the simultaneously acquired MR data, the MR data cannot be treated as discrete sequences, but as the continuous flow of information. This is due to differences in the time required for data collection to generate PET and MR images.
This work describes the development and optimization of a pipeline for the reconstruction and analysis of PET data in a brain-dedicated prototype PET/MR system, the BrainPET (Siemens Healthcare). First, the performance of the BrainPET system was optimized for neurological imaging. MR-hardware interference and characteristics of the PET camera were quantified and a method for multimodal alignment was developed. To simplify and streamline the reconstruction and quantification process, a platform was designed which utilizes the functionality of a number of specialized brain imaging analysis software packages in an automated fashion. Second, MR-based methods addressing specific challenges to PET quantification were addressed. Simultaneously acquired structural MR data was used to correct the PET data for attenuation and partial volume effects. The use of MR data for motion correction was addressed and a unified algorithm which derives motion estimates from the PET data when MR data is unavailable was presented. Finally, the value of the optimized PET processing for neurological studies was evaluated in three instances: first an upper limit on the physiologic noise introduced by MR imaging on cerebral metabolism was estimated using PET and found to be minimal; next the benefit of MR-based motion correction and partial volume effect correction were estimated in a patient study; and lastly, a method to derive the PET radiotracer input function from the PET data using multiple MR sequences was presented.Biophysics
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Sadrmomtaz, Alireza. "Modification of a medical PET scanner for PEPT studies." Thesis, University of Birmingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.668322.
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Welsh, Gabriel Elizabeth. "Development of structural order in PET/PEN random copolymers." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.625079.
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Di, Giuseppe Sara. "Nuove tecniche di diagnostica per immagini: La pet/ct." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8996/.
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L'obiettivo di questo studio è quello di mettere in luce i diversi fattori che, negli ultimi anni, hanno portato ad un impiego sempre più diffuso della PET in ambito clinico, in Italia e all'estero.
La recente integrazione delle informazioni funzionali della PET con le informazioni morfologiche di una TC, mediante tomografi ibridi PET/CT, ha radicalmente cambiato l’approccio alla stadiazione e al follow-up dei pazienti, rendendo questa tecnica una delle massime espressioni della moderna diagnostica per immagini, al giorno d'oggi utilizzata principalmente in campo oncologico.
Nei primi capitoli, dopo un breve richiamo alla struttura della materia, ai concetti di radiazione e decadimento radioattivo, si analizzano le apparecchiature e i principi di funzionamento della tecnica PET/TC.
Successivamente, nel capitolo 4 sono illustrati i diversi tipi di radiofarmaci e le loro applicazioni, con un’attenzione particolare al PSMA, impiegato principalmente nei tumori alla prostata, reni, tiroide e mammella.
Proprio alla cura e alla diagnosi del tumore alla prostata è dedicato il capitolo 5, con un breve confronto tra l’ormai accreditata PET/CT con 18F-Colina e l’innovativa Ga-PSMA PET/CT.
Nel capitolo 6 si prendono in considerazione le procedure e i protocolli da seguire durante un esame PET/TC, le misure di preparazione, prevenzione e le precauzioni che pazienti e personale sanitario devono osservare.
Nel capitolo 7, infine, un breve cenno alle ultime innovazioni tecnologiche: imaging ibrido PET/MRI e fotomoltiplicatori SiPM.
Le fonti bibliografiche citate constano principalmente di articoli in lingua inglese pubblicati sul portale PubMed. Parte della documentazione relativa alla progettazione dell'apparecchiatura PET/CT e al suo utilizzo è, invece, stata fornita da personale dell'arcispedale Santa Maria Nuova di Reggio Emilia.
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Sontikaew, Somchoke. "PET/organoclay nanocomposites." Thesis, Brunel University, 2008. http://bura.brunel.ac.uk/handle/2438/3280.
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This thesis looks at the study of nanocomposites of Poly(ethylene terephthalate) and organoclays. Two methods of materials blending are investigated for the production of the nanocomposites: solvent blending and melt blending. The main objectives were the investigation of the influence of organoclays and processing conditions on morphological, rheological, mechanical properties, crystal structure and isothermal crystallization kinetics of the nanocomposite and a comparison with unfilled PET. In solvent blending, the use of long sonication time and epoxy led to the formation of a two-dimensional network structure of long, thin particles in a solvent blended PET nanocomposite at low clay loading. The clay network structure seemed not to affect the tensile properties. The long, thin particles were able to be separated and dispersed further by high shear in a twin screw extruder, resulting in a high level of separation and dispersion. The crystallization of the solvent blended nanocomposite was not only influenced by the nanoclay but also by the residual solvent. The extent of clay dispersion did not affect the crystallization of the solvent blended sample. Both solvent blended and melt blended nanocomposites showed that increasing the amount of surfactant improved the degree of nanoclay dispersion in the PET that led to an enhancement in the tensile properties of the nanocomposite compared to the unfilled polymer. The degradation of the organoclay during melt blending did not limit the nanoclay dispersion in the PET. The low thermal stability of the organoclay reduced the strength of the crystalline nanocomposite but it did not affect the strength of the amorphous nanocomposite. In contrast to the solvent blended sample, the extent of clay dispersion influenced the crystallization of the melt blended sample. The poorly dispersed particles were more efficient in nucleating PET crystallization than the well dispersed particles. The crystallization rate of PET increased as the surfactant concentration decreased.
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McLennan, Andrew. "Dynamic PET reconstruction." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.543034.
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Cooper, Christopher Robert. "Novel PET sensors." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368518.
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Chan, Kit-sum, and 陳潔沁. "18F FDG PET." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://ndltd.ncl.edu.tw/handle/53448261961859138754.
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Alvarez, De Los Santos Mirella Alexandra, Navarro Nilson Aldinho Arispe, Bastidas Derlys Gustavo Palacios, Bernal Jonathan Torres, and Rengifo Pamela Andrea Zelada. "Pet Society App." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2021. http://hdl.handle.net/10757/657392.
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En este presente trabajo, los integrantes de este nuevo proyecto y también estudiantes de diferentes carreras en la Universidad Peruana de Ciencias Aplicadas, brindaremos una aplicación llamada Pet Society que queremos brindarle a cada persona en Lima la oportunidad de acceder a una plataforma única, sencilla y eficaz para que puedan obtener el mejor servicio asociado a los engreídos de la casa (sus perritos) en los mejores locales veterinarios en todo Lima Metropolitana, con el fin de hacer esta búsqueda más sencilla, veloz y personalizada con los mejores precios del sector y con el mejor servicio y atención garantizada. Asimismo estaremos en constantes innovaciones para mejorar la plataforma, los servicios y realzar los precios accesibles para el mercado veterinario.
Cabe recalcar que hemos realizado una profunda investigación, con el fin de recabar información valiosa, y de esta manera lograremos tener una eficiente y eficaz atención hacia los clientes de nuestro segmento asignado, y que con el tiempo lograremos extender. Además, se busca satisfacer las necesidades básicas de los dueños con respecto a sus mascotas, brindando un servicio diferenciado de alta calidad y fácil acceso. Nuestra plataforma tiene como objetivo conectar a las veterinarias con clientes potenciales que busquen satisfacer las necesidades de sus mascotas, generando un incremento de ventas a las empresas veterinarias y una cartera de opciones a los clientes para que puedan escoger el mejor servicio que estos consideren según sus necesidades. Por esta razón, en el proceso de investigación se tomarán en cuenta las entrevistas y métricas para obtener una retroalimentación acertada para el proyecto.In this present work, the members of this new project and also students of different careers at the Peruvian University of Applied Sciences, we will provide an application called Pet Society that we want to give each person in Lima the opportunity to access a unique, simple and effective so that they can obtain the best service associated with the cocky of the house (their dogs) in the best veterinary premises throughout Metropolitan Lima, in order to make this search easier, faster and more personalized with the best prices in the sector and with the best service and attention guaranteed. Likewise, we will be constantly innovating to improve the platform, services and enhance accessible prices for the veterinary market. It should be noted that we have carried out a thorough investigation, in order to gather valuable information, and in this way, we will achieve efficient and effective service to customers in our assigned segment, and that over time we will be able to extend. In addition, it seeks to satisfy the basic needs of the owners with respect to their pets, providing a differentiated service of high quality and easy access. Our platform aims to connect veterinarians with potential clients who seek to satisfy the needs of their pets, generating an increase in sales to veterinary companies and a portfolio of options for clients so that they can choose the best service that they consider according to their needs. For this reason, the research process will take into account the interviews and metrics to obtain accurate feedback for the project.
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Arroyo, Parado Jovanna Yessica, Anco Jussara Yamileth Contreras, Quispe Christian Raul Manrique, Sandoval Angie Judith Montalbán, and Queria Eduardo Pedro Padilla. "Pet & Care." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/654842.
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El objetivo del presente trabajo de investigación es desarrollar la propuesta de negocios, a través de una plataforma virtual, para la atención de mascotas domésticas, dirigido a los dueños de estas mascotas y centro veterinarios que en los últimos años han tenido un crecimiento del 76% a Nivel Nacional y un 91% solo en Lima Metropolitana.
Se ha identificado un mercado de dueños de mascotas (usuarios), en amplio crecimiento que busca cada día, centros veterinarios especializados que brinden un servicio de alta calidad, conectividad en línea, con información actualizada y al mismo tiempo a costos mínimos necesarios. Así mismos centros veterinarios (clientes) que buscan los conecten con su público objetivo a través de las redes sociales y todo medio informático que incremente su cartera de clientes y que permitan desarrollar la publicidad de sus servicios a bajos costos.
En la primera parte del trabajo se ha desarrollado tanto el planeamiento estratégico con el fin de recopilar información valiosa que ha permitido corroborar supuestos y determinar los puntos más valorados por los usuarios y clientes con respecto a la propuesta de valor y así poder utilizarlas en la fase posterior, es decir en nuestro plan de marketing.
En efecto, en dicho plan, se identificó claramente el público objetivo y se establecieron los medios mediante los cuales se realizará la publicidad y difusión de la propuesta además de todos los componentes del marketing mix. En las secciones posteriores se detalla en plan de operaciones, la estructura organizacional y de recursos humanos, y finalmente se ejecuta un análisis financiero, el cual ha permitido confirmar la factibilidad del proyecto.The objective of this research work is to develop the business proposal, through a virtual platform, for the care of domestic pets, aimed at the owners of these pets and veterinary centers that in recent years have had a growth of 76% at the National Level and 91% only in Metropolitan Lima. A growing market of pet owners (users) has been identified that is looking every day for specialized veterinary centers that provide a high quality service, online connectivity, with updated information and at the same time at the minimum necessary costs. Likewise, veterinary centers (clients) that seek to connect them with their target audience through social networks and all computer media that increase their client portfolio and that allow them to develop the advertising of their services at low costs. In the first part of the work, the strategic planning has been developed in order to collect valuable information that has allowed to corroborate assumptions and determine the points most valued by users and customers with respect to the value proposition and thus be able to use them in the phase later, that is, in our marketing plan. Indeed, in said plan, the target audience was clearly identified and the means by which the proposal will be publicized and disseminated, as well as all the components of the marketing mix, were established. In the subsequent sections, the operations plan, the organizational and human resources structure are detailed, and finally a financial analysis is carried out, which has confirmed the feasibility of the project.
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Ascanoa, Minaya Roxana Lhya, Urutia Oyola Ana Lucía García, Calderón Angélica Natividad Roca, Ueno Patricia Mami Sugimaru, and Carrasco Jose Carlos Vargas. "Service Pet 360." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/654954.
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El presente proyecto consiste en un modelo de negocio para la creación de una empresa llamada Service Pet 360 que unifica los servicios principales para atender a perros y gatos, los cuales abarcan servicios de salud, alimentación, entretenimiento, etc. que llegará al cliente mediante una página web donde se podrán encontrar diferentes empresas reconocidas que trabajan con calidad y compromiso para la total seguridad de nuestros clientes (perros y gatos), de esta forma le otorgamos a nuestros usuarios (dueños de mascotas) la posibilidad de escoger entre una cartera de opciones de atención, productos de la más alta calidad y que se encuentren cerca de su ubicación.
Como hemos visto en la actualidad este rubro del cuidado personalizado a las mascotas se ha incrementado de manera significativa y ha tenido buena acogida en el mercado, ya que muchas más personas dedican más que su tiempo una inversión en sus mascotas. Ante ello nace la oportunidad de que Service Pet 360 pueda satisfacer las diferentes necesidades de estas personas y que ayuden a que otros negocios que son nuestros socios estratégicos se den a conocer en el mercado.
Este proyecto de investigación tiene como objetivo demostrar la sostenibilidad y rentabilidad de Service Pet 360 con diferentes estudios de mercado que se realizarán a nuestro público objetivo y desarrollando diferentes estrategias de marketing que logre un mejor posicionamiento en el mercado y ofrecer servicios y productos diferenciados. La empresa conforma un grupo de trabajo óptimo y profesionales calificados para lograr los objetivos propuestos.The project consists of a business model for the creation of a company called Service Pet 360, which provides the main services towards dogs and cats. It includes: health services, food, entertainment, etc. that will reach the customer through the webpage where you can find different companies that work with quality and commitment for the total safety of our clients (their pets). In this way we give our users (dog or cat owners) the possibility of choosing among a range of care options and products of the highest quality, that are close to your location. As you can read on this work, this type of product (personalized pet care) has increased significantly and has been well received in the market, since more people spend more of their time investing in their pets. Thus, the opportunity arises for Service Pet 360 to satisfy the different needs of these people and help other businesses (our strategic partners) become known in the market. This research project aims to demonstrate the sustainability and profitability of Service Pet 360, with different market studies that will be carried out on our target audience, while developing different marketing strategies with the purpose of achieving a better positioning in the market and offer a variety of services and products. The company is formed of optimal teamwork and qualified professionals to achieve the proposed objective: Helping pet owners find the best quality products and services for their dogs or cats, throughout a modern, aesthetically pleasing, helpful and easy-to-use webpage.
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Córdova, López Dina Milagros, Whu Enrique Augusto Chong, Bustos Jorge Germán López, Mamani Rogelio Ramírez, and Padilla Eduardo Javier Vásquez. "The walking pet." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2017. http://hdl.handle.net/10757/622169.
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The Walking Pet, que conecta a través de una aplicación para dispositivos móviles y/o de una página responsive web (que se adapta a varios dispositivos y sistemas operativos), una base de datos de paseadores con una base de datos de clientes registrados para que se acuerden servicios de paseos de perros. El modelo de negocio es uno del tipo de economías colaborativas: los paseadores no son empleados del modelo, son los proveedores directos de la solución del problema. Los ingresos del modelo de negocio son las comisiones que The Walking Pet cobre a los paseadores, de acuerdo a la cantidad de perros que conformen el grupo de salida del paseo. La escala de comisiones es la siguiente por paseos de 30 minutos a una tarifa de S/15 por paseo por perro. A mayor número de perros por grupo de salida, mayores las comisiones porcentuales para el modelo, y a su vez a valores absolutos, mayores los ingresos percibidos por los paseadores (por grupo de salida). La propuesta de valor de nuestro modelo de negocio se fundamenta en cuatro características: Confianza, Seguridad, Oportunidad y paseos en pequeños grupos. Para la característica de seguridad, nos apoyamos en las tecnologías digitales de geo localización y de transmisión de imágenes y videos por internet. La oportunidad es aquella característica que permite al cliente seleccionar el horario o la agenda que mejor se acomode a su necesidad y para ello se ha de contar con la suficiente cantidad de paseadores registrados. Por último evitaremos los paseos en manadas, situación que de acuerdo a nuestra investigación de campo, mucho fastidia a los dueños de perros, por lo que nuestras salidas serán en pequeños grupos de máximo tres perros, estimando el promedio en dos perros por salida.Trabajo de investigación
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Oliveira, Ricardo Vinicius Bof de. "Blendas PET/PS." Florianópolis, SC, 2000. http://repositorio.ufsc.br/xmlui/handle/123456789/78406.
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Neste trabalho foram estudados os efeitos da adição de agente compatibilizante, poli[(estireno)-co-(anidirido maleico)] [SMA] e dos ciclos de reciclagem à blenda PET/PS. Inicialmente foi avaliada a miscibilidade da blenda de poli(tereftalatode etileno) [PET] com poliestireno [PS]. Sendo esta blenda imiscível em toda a faixa de composição, foi estudada a influência da adição de SMA nas propriedades térmicas e na morfologia da blenda PET/PS/SMA. O parâmetro de interação de Flory-Huggings (c12), cujo valor está relacionado com as interações específicas entre os componentes, foi calculado a partir das temperaturas de fusão de equilíbrio do componente semicristalino puro e na blenda, como igual a +0,024. O valor positivo sugere interações desfavoráveis entre os componentes, em concordância com os outros métodos. A viabilidade de reutilização do PET em mistura com outro polímero, foi analisada através de sucessivos processos de extusão, de maneira que as propriedades microscópicas dos componentes puros e das blendas foram estudadas. A pequena redução da massa molar média do PET, não deve prejudicar o reaproveitamento do PET pós-consumo. Para as blendas PET/PS/SMA, o aumento da adesão interfacial, de certo modo, minimiza o efeito causado pela redução de massa molar durante o processo de reciclagem.
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Weirich, Christoph Peter [Verfasser]. "Quantitative PET imaging with hybrid MR-PET scanners / Christoph Peter Weirich." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2014. http://d-nb.info/1052299563/34.
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Weirich, Christoph [Verfasser]. "Quantitative PET imaging with hybrid MR-PET scanners / Christoph Peter Weirich." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2014. http://nbn-resolving.de/urn:nbn:de:hbz:82-opus-50383.
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Zheng, Yiran. "CT-PET Image Fusion and PET Image Segmentation for Radiation Therapy." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1283542509.
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Torrent, Llongarriu Èlia. "Validació de radiofàrmacs pet per al seu ús en humans." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/285415.
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La tomografia per emissió de positrons (PET) és una tècnica d'imatge no invasiva que permet obtenir imatges quantitatives i tridimensionals dels processos biològics i farmacològics en l’organisme. Portar a terme un estudi PET implica l’administració intravenosa d’un radiofàrmac (RF) i l’obtenció de les imatges mitjançant un tomògraf PET. La PET està essent utilitzada en la pràctica clínica per al diagnòstic de diverses malalties com el càncer, la malaltia d’Alzheimer, el Parkinson i l'esquizofrènia, entre d’altres, i també en la investigació pre-clínica i clínica, tant per agilitzar els assaigs clínics amb noves molècules, com per a la recerca translacional.
Segons dades del National Institutes of Health només un 8,7% d’estudis PET realitzats en animals passen a realitzar-se en humans. Això es deu 1) a la pròpia limitació en el trasllat dels estudis d’animals a humans i 2) al cost i a les dificultats associades per aconseguir l’autorització d’ús dels radiofàrmacs PET.
Els RFs són considerats medicaments i com a tals han de ser fabricats conforme a les Normes de Correcta Fabricació i el seu ús ha de ser aprovat per les autoritats sanitàries competents. Això fa que la seva fabricació sigui costosa i tingui la dificultat associada de ser fabricats segons una normativa i guies poc adaptades a les característiques intrínseques dels RFs PET com és la seva curta semivida, de l’ordre de minuts.
L’objectiu d’aquesta tesi és establir unes pautes en el marc de la validació dels mètodes analítics dels RFs PET per tal de poder complir amb la normativa vigent i/o en el cas de mancança de normativa orientar i contribuir a agilitzar els tràmits d’autorització.
Per portar a terme aquesta tesi, es desenvolupa l’exemple de dos RFs marcats amb isòtops diferents: 11C-PIB, marcador de dipòsit de plaques amiloides en el diagnòstic de la malaltia d’Alzheimer, i 18F-FMISO, marcador d’hipòxia tissular en el tractament del càncer.
Al llarg del treball es defineixen les especificacions i es validen els mètodes analítics per cadascun dels RFs. Posteriorment aquests mètodes s’apliquen tant en la validació de procés com en la determinació de l’estabilitat de 11C-PIB i de 18F-FMISO. Com a resultat final s’aconsegueix disposar d’una part de la documentació necessària per tal de garantir que els RFs d’estudi satisfacin les garanties de qualitat. La metodologia aplicada en el treball es pot extrapolar als RFs PET d’administració parenteral, i per tant, la tesi doctoral contribueix a agilitzar els passos per a obtenir la conformitat de les autoritats sanitàries per tal que els RFs PET puguin ser utilitzats tant en el camp de la investigació com en la pràctica clínica.Positron Emission Tomography (PET) is a noninvasive imaging technique that produces three-dimensional quantitative images of biological and pharmacological processes occurring in the body. In order to perform a PET study, a radiotracer should be administrated intravenously, followed by a PET scan acquisition. Nowadays, PET technique is being used clinically to diagnose diseases such as Cancer, Alzheimer, Parkinson and Schizophrenia. PET is also being used in preclinical and clinical research to investigate new molecules with a strong translational component. Based on National Institutes of Health’s data, only the 8,7 % of PET studies in animals are being performed in humans. This can be attributed to 1) the limitation related to the translation of animal’s biodistribution data to humans and 2) the difficulties and costs associated with obtaining Health Authority approval for its human use. Radiotracers are considered a medicinal product so they have to be produced according to the Good Manufacturing Practices and its use has to be approved by the corresponding authorities. All of these procedures raise the cost of a study, besides the fact of adding difficulties because the available guidelines have not been adapted to the intrinsic characteristics of PET radiotracers, like for example, their short half-life (minutes). The objective of this doctoral thesis is to establish the guidelines and analytical procedures for the validation of PET radiotracers, in compliance with the quality and safety requirements. The thesis describes all the procedures for two PET radiotracers, labelled with different radioisotopes: 11C-PIB, which is an amyloid-β deposits imaging agent widely used in Alzheimer’s disease, and 18F-FMISO, which is a specific hypoxia imaging agent for Cancer treatment. Along the thesis, specifications as well as analytical procedures were specified and validated for both radiotracers. Process validation and Stability studies of 11C-PIB and 18F-FMISO were also included. As a result, the thesis defines the documentation needed in order to assure that the radiotracers are produced according to the required Quality Guidelines. The methodology used could be applied to other parenteral PET radiotracers. Thus, the doctoral thesis contributes describing exhaustively all the steps needed to get the Authorities approval for the use of PET radiotracers in both the clinical practice and research.
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Fu, Quan. "Solid state polymerization, processing and properties of PEN/PET blends /." See Full Text at OhioLINK ETD Center (Requires Adobe Acrobat Reader for viewing), 2005. http://www.ohiolink.edu/etd/view.cgi?toledo1122918876.
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Dissertation (Ph.D.)--University of Toledo, 2005.Typescript. "A dissertation [submitted] as partial fulfillment of the requirements of the Doctor of Philosophy degree in Engineering." Bibliography: leaves 272-285.
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FU, QUAN. "Solid State Polymerization, Processing and Properties of PEN/PET Blends." University of Toledo / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1122918876.
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Barros, Adriana de Fátima. "Preparação, caracterização físico-química e avaliação do comportamento térmico e mecânico de blendas de poli (tereftalato de etileno) (PET) e poli (éterimidia) (PEI), PET/PEI." Universidade Federal de São Carlos, 2004. https://repositorio.ufscar.br/handle/ufscar/6102.
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Previous issue date: 2004-11-19Universidade Federal de Sao Carlos
The blends preparation and composites have been one of the techniques more used to make possible properties and to increase the time of useful life of polymers. PET is a polymeric semicrystalline that has a Tg in 75°C and Tm in 245°C. The low value of Tg of PET and its easiness in crystallizing a lot of times points negative not desired can be considered in a certain project. PEI is a polymeric one amorphous with a value of Tg quite loud 215°C. In the mixture of PET (virgin or recycled) with PEI a displacement was verified in Tg of PET, as well as the one of PEI suggesting polymeric miscibility of the two in the melted state and confirmed later on by the negative value of the parameter of certain Flory to thermal treatments. Since the fusion entalpia is proportional to the crystalline fraction, its correlation with the conformer Reason Trans, RT, was found linear and independent of the content of PEI, turning possible to the determination of the degree of cristalinidade of independent PET of which it goes the composition of to blend PET/PEI. From the results of mechanical resistance of the samples submitted to the aging under radiation UV, it was verified that, independent of the type of PET employee, of the time of radiation of the condition dry or after immersion in water, for stabilized blends or not, so much the specific deformation in the rupture, elastic module, the deformation, and calculated elastic energy, they show a continuous tendency of growth with increase of the content of PEI in the mixture. The effective protection of PEI was verified on PET starting from 25% in PEI of up to 200h of exhibition under UV for the dry samples and up to 100h for samples after immersion in water. After thermal cycle it was verified that, depending on the temperature of the test the composition becomes an important factor. The thermal treatment above 90°C in the presence of the blends with larger concentration than 25% in PEI eliminate the tensions frozen during the processing, in other words, physical aging without there is the crystallization of PET, consequently, a significant improvement was observed in the mechanical answer in terms of elastic energy until tenth cycle. The thermal cycle at 120°C and 140°C is committed for the physical aging of PET and crystallization after the first cycle. The results obtained for the blend with content of 25% in PEI, in fact, when compared to the samples of pure PET they evidence the significant gain in the value of the elastic energy, these results suggest the potentiality for a possible application of this blend in the production of pieces whose interest is to guarantee a good resistance to the impact.
A preparação de blendas e compósitos tem sido umas das técnicas mais utilizadas para viabilizar propriedades e aumentar o tempo de vida útil de polímeros. O PET é um polímero semicristalino que possui Tg em 75°C e Tm em 245°C. O baixo valor da Tg do PET e sua facilidade em cristalizar muitas vezes podem ser considerados pontos negativos indesejados em um determinado projeto. A PEI é um polímero amorfo com um valor de Tg bastante alto 215°C. Na mistura de PET (virgem ou reciclado) com PEI foi verificado um deslocamento na Tg do PET, bem como a do PEI sugerindo miscibilidade do dois polímeros no estado fundido e confirmado pelo valor negativo do parâmetro de Flory determinado posteriormente a tratamentos térmicos. Desde que a entalpia de fusão é proporcional à fração cristalina, sua correlação com a Razão de conformação Trans, RT, foi encontrada linear e independente do conteúdo de PEI, tornando possível à determinação do grau de cristalinidade do PET independente de qual for a composição da blenda PET/PEI. A partir dos resultados de resistência mecânica das amostras submetidas ao envelhecimento sob radiação UV, verificou-se que, independente do tipo de PET empregado, do tempo de radiação da condição seco ou após imersão em água, para blendas estabilizadas ou não, tanto a deformação específica na ruptura, módulo elástico, a elongação, e energia elástica calculada, mostram uma tendência contínua de crescimento com aumento do conteúdo de PEI na mistura. Foi verificada a proteção efetiva da PEI sobre o PET a partir de 25% em PEI de até 200h de exposição sob UV para as amostras secas e até 100h para amostras após imersão em água.Após ciclagem térmica verificou-se que, dependendo da temperatura de ensaio de ciclo térmico a composição passa a ser um fator importante. O tratamento térmico acima de 90°C na presença das blendas com concentração maior que 25% em PEI elimina as tensões congeladas durante o processamento, ou seja, envelhecimento físico sem que haja a cristalização do PET, conseqüentemente observou-se uma melhoria significativa na resposta mecânica em termos de energia elástica até o décimo ciclo. A ciclagem térmica a 120°C e a 140°C são comprometidas pelo envelhecimento físico do PET e cristalização após o primeiro ciclo.Os resultados obtidos para a blenda com conteúdo de 25% em PEI, de fato, quando comparados às amostras de PET puro evidenciam o ganho significativo no valor da energia elástica, estes resultados sugerem a potencialidade para uma possível aplicação desta blenda na produção de peças cujo interesse é garantir uma boa resistência ao impacto.
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Kabelíková, Lucie. "Posouzení vhodnosti PET drtě firmy PETKA CZ, a.s. pro výrobu granulátu k potravinářským účelům." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-295712.
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This thesis deals with the recycling of polyethylene terephthalate and its subsequent processing into the form of a regranulate meeting the parameters required for food use. A brief description of recycling technology, PET flake quality rating and input material contamination is provided. Additionally, legislation regarding recycling for food purposes is discussed and regranulation technologies are described. The suitability of these technologies for processing specific flake samples has been confirmed. In the experimental part, differences in the regranulate samples are compared using DSC and FT-IR. It has been found that there are no major differences between food quality samples. Tests were carried out on 200 PET bottles (bottle, label), on which the input material was divided into 16 groups. Groups that are unsuitable for recycling with this technology was defined. In addition, contaminants of the final product were examined. Their approximate composition was determined and the relationship between the labels of the bottles at the inlet and the impurities at the outlet was found. Appropriate solutions have been proposed to reduce this contamination
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Swoboda, Benjamin. "Amélioration du comportement au feu de PET et d'alliages PET/PC recyclés." Montpellier 2, 2007. http://www.theses.fr/2007MON20150.
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Nordenberg, Marcus. "PET – Plate Evaluation Tool." Thesis, Mittuniversitetet, Avdelningen för data- och systemvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-30226.
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Denna rapport har för avsikt att att beskriva arbetet kring utvecklingen av verktyget PET – Plate Evaluation Tool, som är en applikation avsedd att skanna, presentera, spara samt utvärdera målade plåtar i målningslinjer på SSAB Special Steels i Oxelösund. Till hjälp används det öppna biblioteket OpenCV som är ett bibliotek för datorseende. Med hjälp av detta vävs en bild samman när plåtar passerar en eller två kameror. Släpljus från en ljusramp som genererar en homogen ljusbild används för att tydligare framhäva brister. Verktyget identifierar sedan bristerna på plåtens undersida i syfte att hjälpa operatören att se dessa. Resultaten presenteras sedan bl.a. i ett webb-verktyg som använder sig av Java EE-standarden samt PrimeFaces. Webb-verktyget skapar spårbarhet som förenklar mycket arbete kring eventuella reklamationer, eller andra kvalitetsförbättringar och vilket genomslag dessa får. För operatörernas del presenteras resultaten i en skräddarsydd bild skriven i Java där operatören kan analysera bilden i mer detalj. Vidare undersöks och jämförs sedan vilka filter och parametrar som är lämpligast, och hittar utvalda brister i plåtar på bästa sätt. Projektet undersöker också möjligheten att genom denna teknik kunna utläsa stämplar som är stansade i plåten. Applikationen har fått mycket bra bemötande från de som använder den mest, nämligen operatörerna på berörda målningslinjer. De två filter som skrevs har visat sig kunna identifiera de brister de skall på ett bra sätt och kvalitén på de bilder som vävs samman har visat sig vara så pass bra att stämplar kan utläsas.
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McNicholas, June. "Pet ownership and health." Thesis, University of Warwick, 1998. http://wrap.warwick.ac.uk/3031/.
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This thesis presents three classes of mechanism that may explain reported associations between pet ownership and health benefits. The first suggests any association is noncausal. Studies 1-3 examine candidate factors to explain both health advantages and likelihood of pet ownership. Type A behaviour was hypothesised to be associated with higher risk of illness and lower likelihood of pet ownership. Hardiness was hypothesised to be associated with better health and increased likelihood of pet ownership. Neither hypothesis was supported. The second class of explanation suggests that pets indirectly effect health by acting as social facilitators of human-human interactions. Enhanced social contact may lead to health advantages. Studies 4-6 examine the robustness of the catalysis effect of Pets and its impact on owners' social networks. Whilst the catalysis effect was found to be robust in generating social contacts, these were superficial and not regarded as providing relationship functions likely to enhance health. The third class of explanation suggests pets have direct effects on health through the nature of the relationship with the owner, or through physiological effects such as reduced cardiovascular arousal to stress. Study 7 indicates that pets serve valuable supportive functions for normal children. Study 8 found that young people with autism demonstrate positive behaviours within their relationships with pets which they do not with people. Study 9 found the relationships between people with physical disabilities and their service dogs serve many supportive, as well as instrumental, functions and that this is associated with better self-perceived health. Studies 10 and 11 found no evidence that pet presence moderates cardiovascular reactivity to a laboratory stress task. Little evidence was found of an association between pet ownership and health advantages, although it is clear that pets can be significant and valued relationships for their owners.
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Barrantes, Barba Luciana Antonella, Salazar Claudia Micaela Gallegos, Heredia Alessandra Nikitza Padilla, Ruiz Alessandra Camila Palacios, and Correa Rafaela Rivera. "Pet & Vet club." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2021. http://hdl.handle.net/10757/656836.
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En el presente trabajo de investigación, se desarrolla la validación de la idea de negocio de la creación del aplicativo Pet & Vet Club. Se trata de una plataforma de servicios integrados para mascotas: teleconsultas, entrenamiento y tienda online de productos. Este negocio está dirigido a los dueños de mascotas, tanto hombres como mujeres entre los 18 y 50 años, residentes de Lima Metropolitana y pertenecientes a los niveles socioeconómicos A y B.
Se estableció la tendencia de crecimiento de servicios relacionados a las mascotas como marco de referencia para determinar el potencial del modelo de negocio. Tras el análisis de fuentes primarias y secundarias, se pudo observar que tanto el mercado de teleconsultas como el de compras online para mascotas presentan un importante desarrollo que puede ser aprovechado por la presente aplicación, debido a que no existen competidores con la oferta exacta. La propuesta de valor del modelo de negocio demostró su viabilidad en el mercado limeño con el objetivo de resolver las necesidades de los nuevos consumidores.
Por último, se realizó el plan financiero del proyecto con la finalidad de evaluar la viabilidad del proyecto. Se identificó la inversión inicial necesaria, los costos operativos, los gastos administrativos y de ventas, así como también se realizó una estimación de las ventas en base al concierge y a fuentes secundarias. Finalmente, se concluyó que el proyecto es viable, dado que, se obtuvo un VAN positivo, una TIR mayor a la tasa de descuento y el PRD es de 2,72 años.In this research, the validation of the business idea for the creation of the Pet & Vet Club application is developed. It is a platform of integrated services for pets: teleconsultations, training and online products store. This business is aimed at pet owners, both men and women between 18 and 50 years old, who reside in Metropolitan Lima and belong to the A and B socioeconomic levels. The growth trend of pet-related services was established as a frame of reference to determine the potential of the business model. After the analysis of primary and secondary sources, it was observed that both the market for teleconsultations and the online shopping for pets present an important development that can be taken advantage of by this application, since there are no competitors with the exact offer. The value proposition demonstrated its viability in the Lima market in order to meet the needs of new consumers. Finally, the financial plan of the project was carried out in order to evaluate the feasibility of the project. The initial investment, operating costs, administrative and sales expenses were identified, as well as an estimate of sales based on the concierge and secondary sources. Finally, it was concluded that the project is viable given a positive NPV, an IRR greater than the discount rate and the DPP of 2.72 years.
Trabajo de investigación
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Olshen, Adam B. "Modeling PET blood curves /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/9530.
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Matos, Tassio Francisco Lofti. "Avaliação da viabilidade de reintegração de resíduos de PET pós-consumo ao meio produtivo." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-20012010-103411/.
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Entre os materiais presentes nos resíduos sólidos domiciliares, os resíduos poliméricos pósconsumo representam cerca de 27% do volume total da coleta convencional, segundo Matos (2006), com o agravante da degradação lenta, comprometendo a vida útil dos aterros sanitários e poluindo o meio urbano. Dos resíduos poliméricos, destaca-se o Poli (tereftalato de etileno) PET. O PET é utilizado em embalagens alimentícias e, preferencialmente, no envasamento de bebidas carbonatadas e água mineral com gás. O consumo das embalagens de PET tem sido crescente, o que gera uma presença maior deste resíduo no meio ambiente. A reintegração do PET pós-consumo ao meio produtivo pode ser considerada uma ação mitigatória dos impactos ambientais causados por este resíduo, além de otimizar o ciclo de vida da resina presente na garrafa. A reintegração do PET pós-consumo já é realizada por meio da obtenção de diversos produtos diferentes ao de sua origem (garrafa), com taxas de reciclagens crescentes a cada ano. Entretanto, muitos dos produtos reciclados têm breve vida útil, em decorrência das aplicações que lhes são destinadas. Uma alternativa de vida útil longa para o reciclado de PET seria uma aplicação na construção civil, onde os componentes têm uso de longo prazo, além de ser mais uma opção para suprir o consumo elevado de recursos naturais desta indústria. Neste trabalho foi realizada uma avaliação da viabilidade de reintegração dos resíduos de PET pós-consumo ao meio produtivo, visando os potenciais de disponibilidade da matéria-prima e de propriedades intrínsecas e de desempenho tecnológico do produto reciclado para a indústria da construção civil. A estratégia metodológica da pesquisa compreendeu duas vertentes de avaliação: a gestão dos resíduos e as propriedades e desempenho tecnológico do produto reciclado. O método de avaliação da gestão dos resíduos compreendeu os procedimentos de uma pesquisa exploratória e documental, visando identificar o modelo de recuperação associado às dimensões básicas da logística reversa, assim como o potencial das cadeias de suprimento direto e reverso das garrafas de PET. O método de avaliação tecnológica foi desenvolvido por meio de pesquisa experimental, onde o produto reciclado foi obtido por reciclagem mecânica, compreendendo os processos de revalorização e transformação por injeção, e submetido a diversos ensaios para caracterização das propriedades intrínsecas e o desempenho tecnológico. Destaca-se nos resultados, em relação à avaliação da gestão de resíduos, que a logística reversa das garrafas de PET tem no fator econômico a maior motivação, e, referente à avaliação tecnológica, que os produtos reciclados apresentam perda de desempenho a partir do quarto ciclo de reciclagem, decorrente da degradação das cadeias poliméricas em função das sucessivas reciclagens. A Análise dos resultados permite concluir que existe viabilidade para a reintegração dos resíduos de PET pós-consumo ao meio produtivo da construção civil, visando à aplicação como componente construtivo, considerando as condições de reciclagem adotadas na pesquisa e o potencial de disponibilidade e propriedades de desempenho tecnológico.Post-consumer polymer materials in household wastes (HW) represent approximately 27% of the total volume of conventional garbage collections, according to Matos (2006). The degradation of these wastes is extremely slow, thus compromising the useful life of sanitary landfills and polluting the urban environment. PET poly(ethylene terephthalate) stands out among these polymer wastes, since it is widely used in food packaging and especially for bottling carbonated drinks and mineral water with gas. The use of PET packaging has been increasing steadily, leading to its ever greater presence in the environment. The reintegration of post-consumer PET into production represents an alternative to mitigate the environmental impacts caused by this waste, as well as to optimize the life cycle of the resin contained in PET bottles. Post-consumer PET is already being recycled into a variety of products for purposes other than their original one (bottles) and recycling rates are increasing yearly. However, many recycled products have a very short service life due to the applications in which they are used. An alternative to lengthen the service life of recycled PET would be its application in civil construction, whose components have long-term uses. This would also represent an additional option to help meet this industrys high demand for natural resources. The present study evaluated the feasibility of reintegrating post-consumer PET into production, in view of the large potential availability of this raw material and the intrinsic properties and technological performance of the recycled product for the construction industry. The methodological strategy of this research comprised two lines of investigation: evaluation of waste management, and evaluation of the properties and technological performance of the recycled product. The evaluation of waste management comprised an exploratory and documental research to identify the product recovery model associated with the basic dimensions of reverse logistics, as well as the potential of the direct and reverse supply chains of PET bottles. The technological evaluation was based on experimental research, which involved the mechanical recycling, since the revaluation processes and transformation for injection of post-consumer PET, followed by several tests to characterize its intrinsic properties and technological performance. With regard to waste management, the results highlight the fact that the reverse logistics of PET bottles is driven mostly by economic factors. From the technological standpoint, the results indicate that recycled PET products show a loss in performance after the 4th cycle of recycling due to the degradation of their polymeric chains in response to successive recycling. An analysis of the results leads to the conclusion that it is feasible to reintegrate post-consumer PET into production, applying it as a component material for civil construction, based on the recycling conditions adopted in this research, the potential availability of post-consumer PET and its properties of technological performance.
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Prette, Lucas Del. "Caracterização físico-química de PET ramificado e de suas blendas com PET reciclado." Universidade Federal de São Carlos, 2004. https://repositorio.ufscar.br/handle/ufscar/803.
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Previous issue date: 2004-05-10Financiadora de Estudos e Projetos
The growing concern with the solid residues management, observed in the last decade, due to its huge amount and impact, has motivated the search for recycling processes, where these residues can be reprocessed to generate new products, enlarging the cycle of materials and energy which are present in them. Special attention is given to the recycling of PET from containers of carbonated drinks. During the recycling of PET, the action of degradative fenomena creates a recycled resin with inferior properties, when compared to the original one, which difficults the use in new cycles of processing. The use of processing additives can overcome this effect. The improvement on the processability and modifications in the final properties of products made with blends of branched and linear resins have been reported in the literature. The branched resin could act as a processing additive. Even though some studies have characterized branched PET resins, the mixture of branched PET with recycled PET has not been reported before. Therefore, this study has as objective the characterization of a branched PET resin for use as processing additive in recycled PET and the characterization of the properties of the blends made with these two resins. In a first step, the characterization of the branched and recycled PET has been performed, and their properties compared with a bottle grade PET resin. The resins have been reprocessed to study the effect of the reprocessing over their properties. Modifications on the viscoelastic properties have been observed; the melt viscosity diminished, due to the degradation suffered during the process; the branched resin showed higher viscosity and melt strength. Next, the branched and recycled PET were blended. Improvements on the rheological properties were observed. The blends showed potential for use in transformation processes where higher melt strength is required.
A crescente preocupação com a gestão de resíduos sólidos, observada na última década, em virtude de sua enorme quantidade e impacto ambiental, tem motivado a busca por processos de reciclagem, onde estes resíduos podem ser reprocessados de modo a gerarem novos produtos, ampliando o ciclo dos materiais e energia neles contidos. Especial atenção tem sido dada para a reciclagem do poli (tereftalato de etileno), PET, advindo de embalagens de bebidas carbonatadas. Durante a reciclagem do PET a ação de fenômenos degradativos produz uma resina reciclada com propriedades inferiores à original, dificultando novos ciclos de processamento. O uso de aditivos de processamento pode compensar esse efeito. A melhoria na processabilidade e modificações de propriedades finais de produtos feitos com misturas de resinas ramificadas e lineares foram reportadas na literatura. A resina ramificada atuaria como aditivo de processamento. Embora alguns estudos tenham realizado a caracterização de resinas de PET ramificado, a incorporação do PET ramificado em blendas com PET reciclado não foi reportada. Assim, este estudo tem como objetivos a caracterização de uma resina de PET ramificado para uso como aditivo de processamento em PET reciclado e das propriedades das blendas formadas pelas duas resinas. Em uma primeira etapa foi feita a caracterização do PET ramificado e do PET reciclado usados no trabalho, em comparação com uma resina de PET grau garrafa. As resinas foram reprocessadas para o estudo do efeito do reprocessamento sobre suas propriedades. Modificações das propriedades viscoelásticas foram observadas; a viscosidade do fundido apresentou queda significativa, em virtude da degradação sofrida durante o processo; a resina ramificada apresentou maior viscosidade e resistência do fundido. A seguir efetuou-se a mistura do PET ramificado com o reciclado. Melhorias nas propriedades reológicas foram observadas. As blendas apresentaram potencial para uso em processos de transformação para os quais maior resistência do fundido é requerida.
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Romão, Wanderson. "Metodologia para detectar a presença do PET reciclado em embalagens PET para alimentos." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248626.
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Orientador: Marco-Aurelio De PaoliDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: Atualmente, o Brasil apresenta um dos maiores índices mundiais de reciclagem mecânica do poli (tereftalato de etileno), PET. O sucesso desse termoplástico na indústria de reciclagem deve-se à sua ampla diversidade de aplicações. As embalagens recicladas grau alimentício podem ser misturadas com a resina virgem e reprocessadas. Três metodologias foram estudadas para detectar a presença do PET pós-consumo graugarrafa (PETpc-btg) em PET virgem grau-garrafa (PETv-btg): calorimetria exploratória diferencial (DSC), espectrometria de massas (MALDI-TOF MS) e Fluorescência de raios-X (XRF). Amostras de PETv-btg de três fabricantes foram analisadas: Braskem, Rhodia e Eastman. Amostras de PETpc-btg submetidas ao processo super-clean® também foram analisadas. Elas apresentam a mesma [h] do PETv-btg e foram fornecidas pela empresa Bahia PET. Amostras de PETv-btg Braskem e PETpc-btg foram misturadas e processadas em nosso laboratório em diversas proporções através de um misturador interno acoplado ao reômetro de torque. Os resultados de DSC mostram que a Tm, Tc, DCp e a cinética de cristalização são as principais propriedades térmicas que servem para diferenciar entre PETv-btg e PETpc-btg. Utilizando a técnica de MALDI-TOF MS aliado ao PCA (Análise Componentes Principais), foi possível distinguir as amostras em vários grupos. Esses grupos eram separados em função de alterações químicas como: variações na viscosidade intrínseca ([h] 0,80 e [h] = 0,65-60); submetidas e não submetidas a algum processo industrial; wt % de PETpc-btg em PETv-btg Braskem; e variação no processo de síntese do polímero (fabricante). A partir desses resultados foi possível construir um modelo de calibração, onde ele consegue distinguir entre uma amostra de PETv-btg e uma amostra de PETpc-btg. As medidas de XRF mostraram que alguns fabricantes utilizam mais de um catalisador para o processo de síntese do PETv-btg. A Braskem utiliza manganês e antimônio. Portanto, o modelo de previsão funciona para prever a wt % PETpc nas misturas que foram utilizadas na construção dele, como é o caso das resinas de PETv-btg Braskem e PETpc-btg. Observamos também, através das medidas de XRF, que o teor de Ferro presente no PET aumenta em função do processo de reciclagem. Esta variável poderá ser utilizada para a construção de um modelo quimiométrico abrangendo uma maior quantidade de variáveis
Abstract: Recently, Brazil recorded mechanical recycling of the poly (ethylene terepththalate), PET, the highest in the world, corresponding to about 53 wt %. This success in the recycling industry is due to the wide range of its applications, from textiles to packaging for the food industry. The recycled food-grade packaging could be mixed with virgin resin and reprocessing. Three methodologies were used to detect the presence of the bottle-grade post-consumption PET (PETpc-btg) in the bottle-grade virgin PET (PETv-btg): differential scanning calorimetry (DSC), x-ray fluorescence and matrix assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS). PETv-btg samples were supplied by the manufacturers (Braskem, Rhodia and Eastman). Samples from a superclean ® process (Bahia PET Reciclagem) were also analysed. All samples had the same intrinsic viscosity values, [h]. Braskem PETv-btg and PETpc-btg samples were blended and processed in different proportions in our laboratory using a HAAKE mixer system. DSC results show that cristallization kinetics, heat capacity (DCp), melting and crystallization temperature are the principal thermal properties that can be used to distinguish between PETv-btg and PETpc-btg. MALDI-TOF MS results together with PCA (principal component analysis) was used to classify the samples into several groups: intrinsic viscosity changes ([h] 0,80 e [h] = 0,65-60); processed and not submitted to some industrial process; wt % PETpc-btg in the PETv-btg Braskem; synthesis process change (manufacturer). From these results, it was possible to creat a calibration model, that differentiated between PETv-btg and PETpc-btg resins. However, we were not able to forecast the percentage of PETpc-btg in the PETv-btg. A model can be made from processed samples where its Mw could be corrected for solid state polymerization or the super-clean® process. XRF results show that some manufacturers use one or more catalysts for PETv-btg synthesis. The Braskem resin is made using manganese and antimony catalysts. Therefore, the prediction model is valid only when the origin of the studied mixture is known, such as PETv-btg/PETpc-btg processed blends. For other resins, the prediction model does not work. The Braskem resin had characteristics distintct from the others. We observed also that the Fe concentration in PET increase in as a function of the recycling process. Therefore, this variable could be used, in the future work, to create chemometric models incluing a higher number of variables
Mestrado
Físico-Química
Mestre em Química
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Forgione, Kasey-Lee. "PET/CT-guided percutaneous liver biopsies or ablations using 20-second PET acquisitions." Thesis, Boston University, 2012. https://hdl.handle.net/2144/12386.
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Thesis (M.A.)--Boston University
PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.Purpose: To determine the targeting accuracy of 20-second breath-hold PET scans versus up to 180-second summed, breath-hold PET scans during PET/CT- guided IR procedures for FOG-avid liver lesions. If feasible, single breath-hold PET scans may decrease scan times during PET/CT-guided procedures and improve PET/CT image co-registration for targets subject to respiratory motion. Materials and Methods: Ten patients with 13 liver lesions visible on FOG PET and unenhanced CT underwent PET/CT-guided liver biopsy or tumor ablation using respiratory-bellows-monitored, breath-hold PET and CT acquisitions. Nine 20-second, breath-hold PET scans and one breath-hold CT scan were obtained for each planning PET/CT scan. 20, 40, 60, and 180-second PET scans were reconstructed for each patient. Four interventional radiology readers reviewed 40 PET datasets followed by 10 CT datasets, both in random order, and marked the epicenter of the tumors using OsiriX PACS DICOM Viewer. 3-dimensional differences (distance errors) in target localization for each PET dataset compared to 180-second PET or CT, as gold standards, were analyzed with multiple regression models. Tumor sizes and FOG-avidities were correlated with magnitudes of targeting errors using Pearson correlation analysis. Statistical tests were two-sided; P < .05 was considered significant. Results: 20-second PET targeting errors compared to 180-second PET ranged from .7 - 153 mm (mean 19.2 mm) and were not significantly different than 40 or 60-second PET (P= .83 &.60). 20-second PET targeting errors compared to CT ranged from 1.4-468 mm (mean 37.3 mm) and were not statistically different than 40, 60, or 3 minute PET (P= .88 , .88, & .61 ). Overall, PET targeting errors were inversely correlated with tumor size (P< .001) and FOG avidity (P< .001 ). Conclusion: Targeting accuracy using 20-second breath-hold PET is comparable to longer PET acquisitions up to 180-seconds. PET targeting errors are larger for small tumors or tumors with low FOG avidity regardless of PET acquisition time. PET/CT scans for guiding percutaneous liver procedures are feasible in two breath-holds, one for CT and one for PET acquisitions, without compromising accuracy.
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Şensoy, Levent. "Geo-Pet : a novel generic Organ-Pet for small animal organs and tissues." Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/3186.
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Reconstructed tomographic image resolution of small animal PET imaging systems is improving with advances in radiation detector development. However the trend towards higher resolution systems has come with an increase in price and system complexity. Recent developments in the area of solid-state photomultiplication devices like silicon photomultiplier arrays (SPMA) are creating opportunities for new high performance tools for PET scanner design.
Imaging of excised small animal organs and tissues has been used as part of post-mortem studies in order to gain detailed, high-resolution anatomical information on sacrificed animals. However, this kind of ex-vivo specimen imaging has largely been limited to ultra-high resolution μCT. The inherent limitations to PET resolution have, to date, excluded PET imaging from these ex-vivo imaging studies.
In this work, we leverage the diminishing physical size of current generation SPMA designs to create a very small, simple, and high-resolution prototype detector system targeting ex-vivo tomographic imaging of small animal organs and tissues.
We investigate sensitivity, spatial resolution, and the reconstructed image quality of a prototype small animal PET scanner designed specifically for imaging of excised murine tissue and organs. We aim to demonstrate that a cost-effective silicon photomultiplier (SiPM) array based design with thin crystals (2 mm) to minimize depth of interaction errors might be able to achieve sub-millimeter resolution. We hypothesize that the substantial decrease in sensitivity associated with the thin crystals can be compensated for with increased solid angle detection, longer acquisitions, higher activity and wider acceptance energy windows (due to minimal scatter from excised organs).
The constructed system has a functional field of view (FoV) of 40 mm diameter, which is adequate for most small animal specimen studies. We perform both analytical (3D-FBP) and iterative (ML-EM) methods in order to reconstruct tomographic images. Results demonstrate good agreement between the simulation and the prototype. Our detector system with pixelated crystals is able to separate small objects as close as 1.25 mm apart, whereas spatial resolution converges to the theoretical limit of 1.6 mm (half the size of the smallest detecting element), which is to comparable to the spatial resolution of the existing commercial small animal PET systems. Better system spatial resolution is achievable with new generation SiPM detector boards with 1 mm x 1 mm cell dimensions.
We demonstrate through Monte Carlo simulations that it is possible to achieve sub-millimeter spatial image resolution (0.7 mm for our scanner) in complex objects using monolithic crystals and exploiting the light-sharing mechanism among the neighboring detector cells. Results also suggest that scanner (or object) rotation minimizes artifacts arising from poor angular sampling, which is even more significant in smaller PET designs as the gaps between the sensitive regions of the detector have a more exaggerated effect on the overall reconstructed image quality when the design is more compact. Sensitivity of the system, on the other hand, can be doubled by adding two additional detector heads resulting in a, fully closed, 4π geometry.
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Coker, Audra Lee. "PET/CT shielding design comparisons." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5836.
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The objective of this project was to compare two different methods of calculating
dose through lead-shielded walls in the PET/CT suite at Scott & White Hospital in
Temple, Texas. The ultimate goal was to see which of the two methods agreed with the
actual physical measurements. Minimizing shielding needed in future suite designs
would result in a possible reduction of structural as well as financial burden. Formulas
and attenuation coefficients following the basic January 2006 AAPM guidelines were
used to calculate unattenuated radiation through existing lead walls. The computer code
MCNPX was used to simulate the leaded walls of the PET/CT suite and provide another
set of results. These two sets of results were compared to doses gathered from OSL
badges placed around the suite for a period of two months. For this type of problem,
MCNPX proved to provide results that were inconsistent and unreliable. It was
concluded that the traditional computational methods are the most reliable for designing
shielding in a PET/CT suite.
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Romani, Rafael Fernandes. "Avaliação das características do transporte da membrana peritoneal por meio da comparação de três métodos (PET tradicional, mini-PET e PET modificado)." reponame:Repositório Institucional da UFPR, 2015. http://hdl.handle.net/1884/49048.
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Orientador : Prof. Dr. Marcelo Mazza do NascimentoDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências da Saúde, Programa de Pós-Graduação em Medicina Interna. Defesa : Curitiba, 09/06/2015
Inclui referências : f. 52-59
Resumo: INTRODUÇÃO: O teste de equilíbrio peritoneal (peritoneal equilibrium test) (PET) é o método mais difundido e utilizado para avaliação do transporte de solutos da membrana peritoneal (MP). Outros métodos têm sido descritos a fim de trazer mais informações sobre outros aspectos do transporte de solutos e de água da MP . OBJETIVO: O objetivo principal deste estudo foi de comparar três métodos de avaliação do perfil de transporte da MP: PET tradicional (PET-t, mini PET e PET modificado (PET-mod). MÉTODOS: uma amostra de conveniência de vinte e um pacientes não diabéticos, com idade superior a 18 anos (idade média 58±15 anos) há pelo menos 3 meses (média 18±14 meses) em programa de diálise peritoneal (DP) foram submetidos a realização do PET-t (2,5%-4h) , mini- PET (3,86%-1h) e PET-mod (3,86% - 4h) A concordância entre os três métodos (D/P creatinina, D/D0 glicose) foi verificada por meio da análise análise de variância (ANOVA), coeficiente de correlação de Pearson e análise de Bland-Altman. RESULTADOS: ao se analisar a relação D/P creatinina, entre os três métodos a análise de variância não mostrou diferença significativa entre o PET tradicional e o PET-mod (p=0,746). Por outro lado, isto não foi observado ao se comparar o PET-t e mini-PET (p<0,001) e entre PET- mod e Mini PET (p<0,001) Além disto, houve uma correlação positiva e significativa entre PET-t e PET-mod (r=0,387 ; p=0,009) não se observando tal associação em relação ao PET e mini-Pet (r=0,088 p=0,241). O teste de Bland Altman mostrou que o viés estimado entre PET e PETmod foi -0,029 (p=0,201) e entre o PET-t e miniPET de 0,206 (p<0,001). Ao se avaliar o D/D0 glicose, entre os três métodos, a análise de variância não mostrou diferença significativa entre PET-t e mini-PET (p=0,885) porém com diferença significativa entre PET-t e PET-mod (p=0,003) e entre PET-mod e mini-PET (p=0,002). Além disto, não se observou uma correlação significativa entre PET e PET-mod (r=-0,161 ; p=0,682) e entre PET e Mini Pet (r= 0,002; p=0,586). Pelo teste Bland-Altman o viés estimado entre PET e PET- mod foi 0,124 (p=0,005) e entre PET e mini-PET de -0,013 (p=0,738). CONCLUSÃO: Os resultados apontam uma boa associação entre PET-t e o PET-mod podendo este ser uma alternativa ao PET tradicional por oferecer informações mais acuradas em relação ao perfil de ultrafiltração na DP . Por outro lado, esta associação não se verificou em relação ao Mini-PET. . Palavras chave: diálise peritoneal; teste equilíbrio peritoneal; ultrafiltração; transporte de solutos; PET, MIniPET, PET modificado
Abstract: INTRODUCTION: Peritoneal Equlibration Test (PET) is widely used to evaluate peritoneal transport. New methods have been described to facilitate and improve this evaluation. Here we compared three methods to evaluate peritoneal transport: traditional PET (PET), mini-PET and modified PET (mod- PET). OBJECTIVE: The main objective of this study is to compare three methods to evaluate peritoneal transport: traditional PET, Mini PET and modified PET (mod-PET). METHODS: A convenience sample of twenty-one non-diabetics adults in peritoneal dialysis (PD) for at least 3 months were submitted to PET (2,5%- 4h) , mini-PET (3,86%-1h) and mod-PET (3,86% - 4h). D/P creatinine, D/D0 glucosis and D/P sodium were analised by analysis of variance (ANOVA), Pearson correlation and Bland-Altman test. RESULTS: D/P creatinine ratio was not significant different difference between PET and mod-PET (p=0,746). Besides, there was a significant difference between PET-t and mini-PET (p<0,001) and between mod-PET and mini- PET (p<0,001). There was also a positive and significant correlation between PET-t and mod-PET (r=0,387 ; p=0,009) but not between PET-t and mini Pet (r=0,088 p=0,241). Bland Altman test showed an estimated bias between PET and mod-PET of -0,029 (p=0,201)and between PET and mini- PET 0,206 (p<0,001). D/D0 glucoses had not significant different between PET and mini-PET (p=0,885), PET and PET-mod (p=0,003) and mod-PET and Mini-PET (p=0,002). Moreover, no significative correlation was found between PET and mod-PET (r=-0,161 ; p=0,682) or between PET and Mini- Pet (r= 0,002 (p=0,586). Bland Altman test also showed an estimated bias between PET and mod-PET of 0,124 (p=0,005). Between PET and mini-PET - 0,013 (p=0,738). CONCLUSION: The results shows a good association between PET and Mod-PET .However, this association could not be verified regarding to MiniPET. Key words: peritoneal dialysis; peritoneal equilibration test; solute transport.
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Petrich, Deirdre K. "Pet Bereavement and Families: A Qualitative View." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1217529970.
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STRINGHINI, GIANLUCA. "Development of an innovative PET module." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2019. http://hdl.handle.net/10281/241249.
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Lo scopo di questo progetto ́e lo sviluppo di un rivelatore PET innovativo in grado di raggiungere alte prestazioni per quanto riguarda risoluzione spaziale, energetica e temporale mantenendo la complessit ́a del sistema ragionevolmente bassa. Il modulo PET proposto si basa su una matrice di cristalli scintillanti e un rivelatore (MPPC). Se paragonato ad una configurazione a doppia lettura in cui la luce di scintillazione ́e raccolta da entrambe le estremit ́a del modulo, nella configurazione proposta, un rivelatore ́e sostituito da una guida di luce e un ma- teriale riflettente. La luce raccolta dal secondo rivelatore nella configurazione a doppia lettura ́e invece ricircolata e collezionata dai rivelatori vicini grazie alla guida di luce posizionata sul modulo. Sfruttando questo meccanismo di condivisione della luce, ́e possibile raggiungere le stesse prestazioni di una con-
figurazione a doppia lettura diminuendo il numero di canali richiesti. E ́ inoltre possibile adottare un accoppiamento tra cristalli e rivelatori maggiore di uno ri-
ducendo ulteriormente i canali di lettura. Studiando infatti la distribuzione della luce condivisa ́e possibile identificare il cristallo in cui ́e avvenuta l’interazione del raggio gamma. Numerose matrici sono state testate con differenti configu- razioni di accoppiamento tra cristalli e rivelatore (uno a uno, quattro a uno e nove a uno) e i risultati hanno confermato un ottima capacit ́a di identificazione del cristallo colpito e una risoluzione energetica di 12 % FWHM (configura- zione uno a uno e quattro a uno) e 16% FWHM (configurazione nove a uno). Per quanto riguarda macchine PET con piccolo campo di vista, ́e presente un peggioramento della risoluzione spaziale vicino agli estremi del campo di vista stesso dovuto all’errore di parallasse. Questo ́e mitigato dalla conoscenza della profondit ́a di interazione del raggio gamma (informazione DOI). La possibilit ́a di ottenere questa informazione nel modulo proposto ́e stata testata e una riso- luzione DOI di 3mm FWHM misurata per le configurazioni uno a uno e quattro a uno, mentre per la configurazione nove a uno la risoluzione DOI ́e risultata essere 4 mm FWHM. Al fine di ottenere l’informazione sulla profondit ́a di in- terazione ́e stato necessario introdurre un effetto di attenuazione di luce lungo l’asse del cristallo con l’effetto per ́o di peggiorare le prestazioni temporali del modulo. Un metodo per includere il DOI nella misura della risoluzione tem- porale ́e stato quindi sviluppato. Il modulo proposto presenta una risoluzione temporale di 353 ps FWHM. La seconda parte del progetto ́e lo sviluppo di un algoritmo di ricostruzione di immagini metaboliche capace di includere sia l’informazione temporale che il DOI. L’algoritmo ́e presentato e uno studio di simulazioni condotto al fine di confermare i vantaggi sia dell’informazione DOI che della risoluzione temporale nella qualit ́a delle immagini ricostruite. Per fini- re, uno studio completo sulla PET con informazioni del tempo di volo (TOF) ́e stato effettuato valutando il miglioramento del rapporto segnale-rumore e della risoluzione spaziale in funzione delle prestazioni temporali del sistema.Positron emission tomography (PET) is a technique based on the detection of two back to back 511 keV gamma rays originated by a positron-electron annihilation. The aim of this project is to develop an innovative PET detector module with high performances, in term of spatial, energy and timing resolution while maintaining the overall complexity reasonably low. The proposed module is based on a pixellated LYSO matrix and MPPC detector. Compared to double side readout configuration in which the scintillators are read on both sides by detectors, one detector is replaced by an optical light guide and a reflector. The light collected by the second detector in the double side readout approach is instead recirculated and collected by the nearby detectors thanks to the light guide on top of the module. Enabling this light sharing mechanism allows rea- ching the same performances of a double side readout configuration decreasing the number of detector channels needed. Furthermore, it is possible to adopt a more than one to one coupling between scintillators and detector in order to further decrease the number of channels needed and to improve the spatial re- solution of the system. Studying the shared light distribution allows identifying the crystal in which the gamma ray interaction took place. Several matrices are tested with different coupling between scintillators and detectors (one to one, four to one and nine to one) and the results show good crystals identification capabilities and an energy resolution in the order of 12% FWHM (one to one and four to one configurations) and 16% FWHM (nine o one configuration). For small animal and organ dedicated PET devices, there is a spatial resolution degradation close to the edges of the field of view (FOV) due to parallax error. This effect is mitigated by knowing the interaction position along the crystal main axis and this information is known as depth of interaction (DOI). The DOI capabilities of the proposed module are tested and a value of 3 mm FWHM DOI resolution is reached for the one to one and four to one coupling configuration. For the nine to one configuration a DOI resolution of 4 mm FWHM is obtained. In order to reach the DOI information, an attenuation behavior over the crystal length is introduced but, as drawback, it decreases the timing performances of the proposed module. A method to reduce this effect is presented by including the DOI information in the evaluation of the timing resolution. The module shows a coincidence time resolution of 353 ps FWHM. The second part of this project is focused on the development of an image reconstruction software able to include both the DOI and timing information. The reconstruction algorithm is described and presented and a simulation study is performed in order to confirm the benefits of the DOI and timing in the image quality. Furthermore, a complete time of flight (TOF) study is performed evaluating the improvement of the signal to noise (SNR) ratio and spatial resolution as a function of the timing performances.
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Werner, Peter, Michael Rullmann, Anke Bresch, Solveig Tiepolt, Donald Lobsien, Matthias Schröter, Osama Sabri, and Henryk Barthel. "Impact of attenuation correction on clinical [18F]FDG brain PET in combined PET/MRI." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-205215.
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Background: In PET/MRI, linear photon attenuation coefficients for attenuation correction (AC) cannot be directly derived, and cortical bone is, so far, usually not considered. This results in an underestimation of the average PET signal in PET/MRI. Recently introduced MR-AC methods predicting bone information from anatomic MRI or proton density weighted zero-time imaging may solve this problem in the future. However, there is an ongoing debate if the current error is acceptable for clinical use and/or research. Methods: We examined this feature for [18F] fluorodeoxyglucose (FDG) brain PET in 13 patients with clinical signs of dementia or movement disorders who subsequently underwent PET/CT and PET/MRI on the same day. Multiple MR-AC approaches including a CT-derived AC were applied. Results: The resulting PET data was compared to the CT-derived standard regarding the quantification error and its clinical impact. On a quantitative level, −11.9 to +2 % deviations from the CT-AC standard were found. These deviations, however, did not translate into a systematic diagnostic error. This, as overall patterns of hypometabolism (which are decisive for clinical diagnostics), remained largely unchanged. Conclusions: Despite a quantitative error by the omission of bone in MR-AC, clinical quality of brain [18F]FDG is not relevantly affected. Thus, brain [18F]FDG PET can already, even now with suboptimal MR-AC, be utilized for clinical routine purposes, even though the MR-AC warrants improvement.
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Noonan, Philip John. "An investigation into motion correction schemes for high resolution 3D PET And PET/CT." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/an-investigation-into-motion-correction-schemes-for-high-resolution-3d-pet-and-petct(b52783fa-a5cf-4f85-a050-e57f8f775f45).html.
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Although motion correction in medical imaging is well established and has attracted much interest and research funding, a gap still exists in that there is a lack of reliable, low-cost hardware to enable such techniques to be widely adopted in healthcare. Motion correction of brain Positron Emission Tomography (PET) data for instance is an important step in realising the potential offered by modern high resolution PET scanners. Since it is not likely that subjects can remain stationary throughout the PET scan, which can last 60 minutes or more, accurate and reliable motion tracking is needed to correct the PET data for any observed motion. A commercially available marker based motion tracking system was evaluated and found to produce unreliable data. This was due to the possibility of the tracking tool slipping from the subject. This thesis describes the investigations into alternative and novel tracking techniques for use in PET. These included a markerless tracking system using the Microsoft Kinect (a low cost depth sensor) as well as a multiple target marker tracking system. The performance characteristics of both systems (low cost, high spatial and temporal accuracy, and real-time operation) were evaluated using phantom and clinical experiments. Investigations into using these two tracking techniques in whole body PET, specifically measuring the respiratory rate during lung imaging, were developed and compared against current commercially available solutions.
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Siepe, Bettina Hilda Luise [Verfasser], and Werner [Akademischer Betreuer] Vach. "Die Qualität randomisierter Studien zur Nutzenbewertung von PET bzw. PET/CT : : eine systematische Übersichtsarbeit." Freiburg : Universität, 2014. http://d-nb.info/1123481512/34.
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Schütz, Friederike [Verfasser]. "Positronenemissionstomographie (PET und PET/CT) bei Schilddrüsenkarzinomen : eine systematische Übersicht und Metaanalyse / Friederike Schütz." Halle, 2017. http://d-nb.info/1141678292/34.
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Gonzalez-Espinoza, Cesar. "Synthesis of Gemcitabine Analogues with Silicon-Fluoride Acceptors for 18F Labeling." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3469.
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Gemcitabine (dFdC) is an effective chemotherapeutic nucleoside analogue for treatment of cancers and solid tumors. Gemcitabine’s chemotherapeutic effect is limited by its rapid intracellular deamination by cytidine deaminase into the inactive uracil derivative. Herein, I designed and synthesized two sets of gemcitabine analogues: i) a 4-N-alkyl gemcitabine analogue containing a β-keto sulfonate moiety, and ii) clickable analogues possessing silicon-fluoride acceptor building blocks. Both of these sets of analogues undergo efficient fluorination, including fluorination protocols compatible with 18F labeling.
The synthesis of the 4-N-alkyl gemcitabine analogue bearing β-keto sulfonate moiety began with reaction of 4-N-tosylgemcitabine with 1-amino-10-undecene, followed by a series of oxidation and sulfonation steps which yielded the β-keto sulfonate analogues.
The coupling of gemcitabine with carboxylic acids using peptide coupling conditions afforded 4-N-alkanoyl analogues with a terminal alkyne or azido moiety. Click reaction of these 4-N-alkanoyl analogues with dialkylsilyl building blocks gave 4-N-alkanoylsilanegemcitabine analogue. Reaction of 4-N-tosylgemcitabine with vii functionalized azidoalkyl amines provided 4-N-alkylgemcitabine with a terminal azido group. Coupling of the latter with dialkylsilyl building block provided 4-N-alkylsilanegemcitabine. Fluorination of 4-N-alkyl gemcitabine analogues with β-keto sulfonate moieties and of the trisubstituted silane derivatives with KF and 18-Crown-6 (CH3CN/75°C/0.5-1h), gave the corresponding fluorinated 4-N-alkyl and alkanoyl gemcitabine analogues under conditions that are compatible with protocols for positron emission tomography (PET) 18F labeling. The [18F] 4-N-alkyl and alkanoyl silane gemcitabine analogues were successfully synthesized on microscale and macroscale radiochemical protocols. The biodistribution of [18F] 4-N-alkyl gemcitabine analogue was analyzed via PET imaging. The cytotoxicity activity of the silane gemcitabine analogues were studied in cancer L1210 and HEK293 cell lines and their cellular uptake were investigated using HPLC analysis and fluorescence microscopy.
Reduction of ribono-1,4-lactones and gulono-1,4-lactone as well as ribono-1,5-lactone and glucono-1,5-lactones with LTBH (1.2 equiv.) in CH2Cl2 at 0 °C for 30 min provided the corresponding pentose or hexose hemiacetals in chemoselective fashion and in high yields. Commonly used in carbohydrate chemistry protecting groups such as trityl, benzyl, silyl, acetals and to some extent acyls are compatible with this reduction.
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Liu, Xiaoli. "Redefining Dynamic PET to Improve Clinical Feasibility." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1479832286719247.
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Geraci, Lorenzo. "Studio di contenitori in PET per riempimento a caldo nitro-hot-fill." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11209/.
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Lo scopo di questa attività è approfondire le conoscenze sul processo di riempimento a caldo noto come nitro-hot-fill (NHF) utilizzato per contenitori in PET. Il nostro obiettivo è quello di simulare su scala di laboratorio il processo industriale al fine di ottimizzarne i parametri e aumentare la stabilità dei contenitori anche attraverso l’utilizzo di materie prime con caratteristiche migliorate utilizzando formulazioni adatte ai trattamenti a caldo. Il processo consiste nel riempimento della bottiglia ad una temperatura tra gli 80°/85°C, successivo al quale vi è l’iniezione di azoto al fine di evitare l’implosione durante il raffreddamento fino a temperatura ambiente.
Questo settore del mercato è in forte crescita, molte bevande infatti hanno la necessità di un contenitore asettico; il processo di NHF ha il vantaggio di utilizzare il calore del prodotto stesso al fine di rendere la bottiglia sterile. Da qui nascono le criticità legate al processo, occorre prendere diversi accorgimenti al fine di rendere processabile in questo modo una bottiglia, infatti l’aumento di pressione interna dovuto all’iniezione di azoto si accompagna una temperatura vicina alla temperatura di transizione vetrosa. La nostra attività di ricerca ha focalizzato la propria attenzione sul design della bottiglia, sul processo di stiro-soffiaggio, sull’influenza dell’umidità assorbita nel PET, sul materiale utilizzato e su altri parametri di processo al fine di produrre contenitori in grado di resistere al riempimento NHF.
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McGinnity, Colm Joseph. "Quantitative imaging in epilepsy (PET)." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/40095.
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Introduction Epilepsy is a heterogeneous collection of neurological diseases characterised clinically by recurrent seizures. Pre-clinical models implicate derangements in ligand-gated receptor-mediated neurotransmission in seizure generation and termination. In this thesis, the author quantified activated N-methyl D-aspartate- and opioid peptide receptor availability in adults with focal epilepsy. Methods This thesis consists of three positron emission tomography (PET) studies of adults with focal epilepsy, using [18F]GE-179 (activated NMDA receptors) and [11C]diprenorphine (DPN; opioid receptors) radioligands. A novel resolution-recovery technique, Structural Functional Synergistic-Resolution Recovery (SFS-RR), was applied to pre-existing paired [11C]DPN PET datasets acquired from adults with temporal lobe epilepsy (TLE). Activated NMDA receptor availability was quantified in adults with frequent interictal epileptiform discharges (IEDs), by regional compartmental modelling and model-free voxelwise analyses. Statistical parametric mapping was used to identify significant differences in volumes-of-distribution (VT) between populations. Results [18F]GE-179 had good brain extraction with a relatively homogeneous distribution and moderately-paced kinetics in grey matter. The two brain compartments, four rate-constants model best described the radioligand's kinetics in grey matter. Global increases in [18F]GE-179 VT were seen for seven of 11 participants with frequent IEDs. Focal increases in [18F]GE-179 VT of up to nearly 24% were also identified for three of the 11 participants. A post-ictal increase in [11C]DPN VT was identified in the ipsilateral parahippocampal gyrus. Discussion This first-in-man evaluation of [18F]GE-179 evidenced several properties that are desirable in PET radioligands, but the specificity of binding requires further characterisation. The results suggest focal increases in activated NMDA receptor availability in participants with refractory focal epilepsy, and also post-ictal increases in opioid peptide availability in the parahippocampal gyrus in TLE. Both findings may have pathophysiological relevance, and illustrate the potential of quantitative ligand PET with advanced post-processing to investigate changes in inhibitory and excitatory receptor systems in the epilepsies in vivo.