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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Quantificação da perfusão sanguínea cerebral utilizando arterial spin labeling: aplicações em medidas de territórios vasculares e em imagens funcionais / Cerebral perfusion quantification using arterial spin labeling: applications in vascular territories measurement and functional imaging

Fernando Fernandes Paiva 06 June 2008 (has links)
Arterial spin labeling é uma técnica completamente não invasiva que permite o monitoramento quantitativo da perfusão cerebral e, juntamente com outras técnicas de ressonância magnética, tem se estabelecido como uma excelente ferramenta para estudos relacionados à hemodinâmica e problemas vasculares cerebrais. Dentre as possíveis implementações da técnica, a abordagem contínua, combinada a uma bobina de marcação dedicada, apresenta algumas vantagens com relação à relação sinal-ruído e à deposição de potência de RF. No presente trabalho, estas vantagens foram exploradas na implementação de uma metodologia que permite a obtenção de mapas quantitativos de fluxo sanguíneo cerebral, bem como dos territórios vasculares das principais artérias suprindo o cérebro. Os resultados obtidos em humanos e animais revelam a robustez e aplicabilidade da técnica em estudos da hemodinâmica cerebral. Aplicações em hipertensão comprovam que a técnica é capaz de fornecer informações que podem auxiliar na compreensão de diferentes patologias. A implementação da variante dinâmica da técnica ASL demonstra a versatilidade da metodologia fornecendo ferramentas para uma maior compreensão das características espaciais e temporais da hemodinâmica cerebral. Os resultados demonstram isto tanto em condições de fluxo sanguíneo basal como em hiperemia causada por estímulos funcionais. / Arterial spin labeling techniques allow to obtain quantitative maps of perfusion non-invasively. Along with other MRI techniques, it has proven useful for diagnosis of a variety of cerebrovascular diseases. Amongst the available basic implementations, the continuous approach employing a dedicated labeling RF coil has the advantages of presenting high signal-to-noise ratio and lower RF power deposition. In the present work, these advantages were explored in order to implement a methodology to obtain quantitative maps of cerebral blood flow and the vascular territories of the major cerebral feeding arteries. Human and animal results reveal the robustness and applicability of the technique in cerebral hemodynamic studies. Applications in hypertension show that the technique can provide complimentary information to improve the understanding of neurovascular diseases. The dynamic ASL technique shows the method versatility for studying the spatial and temporal characteristics of cerebral hemodynamics. The results unravel that both under basal and functional hyperemia conditions.
82

Avaliação da perfusão sanguínea cerebral em modelos animais de hipertensão utilizando Arterial Spin Labeling / Cerebral perfusion evaluation in animal models of hypertension using arterial spin labeling

Renata Ferranti Leoni 28 September 2011 (has links)
A hipertensão arterial é uma doença que aflinge mais de um quarto da população adulta mundial e mais da metade da população idosa. Ela é o principal fator de risco para doenças cerebrovasculares e o segundo fator de risco, após idade, para os acidentes vasculares cerebrais (AVC) hemorrágico e isquêmico. É também a principal causa de declínio cognitivo e demência, incluindo a doença de Alzheimer. A hipertensão causa remodelamento vascular e modifica os mecanismos de regulação do fluxo sangüíneo cerebral, incluindo a hiperemia funcional, a autoregulação cerebrovascular e a regulação endotelial. Portanto, pesquisas contínuas sobre os efeitos da hipertensão na função cerebrovascular são cruciais para o desenvolvimento de terapias preventivas que objetivam minimizar os riscos de desenvolvimento de doenças cerebrovasculares. No presente estudo, a perfusão cerebral de um importante modelo experimental de hipertensão, o rato SHR (do inglês spontaneously hypertensive rat), foi avaliada utilizando as técnicas de arterial spin labeling (ASL), que permitem a quantificação não-invasiva da perfusão. Utilizando o método de ASL contínua, o fluxo sangüíneo cerebral foi quantificado para todo o cérebro do rato sob condições de normocapnia e hipercapnia. Resistência cerebrovascular aumentada e reatividade vascular ao CO2 reduzida foram observadas em SHR adultos, confirmando que a hipertensão leva à redução progressiva da capacidade de dilatação da vasculatura cerebral. A técnica de ASL dinâmica permitiu medir o fluxo sangüíneo cerebral funcional evocado por estimulação somatosensorial. Além de apresentarem resposta hemodinâmica positiva à estimulação, os ratos hipertensos também apresentaram resposta hemodinâmica negativa em áreas circundantes àquelas ativadas positivamente. Foi mostrado que esse resultado está relacionado com um efeito puramente hemodinâmico causado pela pressão arterial elevada e pela reserva vascular alterada do SHR. Experimentos farmacológicos mostraram diferenças na modulação do acoplamento neurovascular de SHR quando comparado com rato normotenso. Além disso, SHR submetidos à oclusão temporária da artéria cerebral média apresentaram maior volume da lesão isquêmica e do edema cerebral, redução severa da massa corporal e déficits neurológicos piores do que ratos normotensos. Esses resultados estão relacionados à autoregulação cerebral alterada e ao desenvolvimento prejudicado da circulação colateral em SHR. Em suma, os achados do presente estudo mostraram que a hipertensão resulta em reserva vascular prejudicada, acoplamento neurovascular alterado e piores conseqüências a um AVC isquêmico. / Hypertension is a disease that afflicts more than a quarter of the general population and more than half of the elderly population. It is the most important modifiable risk factor for cerebrovascular diseases and the second most important risk factor, after age, for hemorrhagic and ischemic stroke. It is a leading cause of cognitive decline and dementia, including the Alzheimer\'s disease. Hypertension causes vascular remodeling and modifies the intricate mechanisms of cerebral blood flow (CBF) regulation, including functional hyperemia, cerebrovascular autoregulation, and endothelial regulation. For all of the above, continued research on the effects of hypertension on cerebrovascular function is a crucial step in the design of preventive therapies aimed at minimizing the risk of development of cerebrovascular disease. In the present work, cerebral perfusion of an important experimental model of hypertension, the spontaneously hypertensive rat (SHR), was evaluated using the arterial spin labeling (ASL) techniques, which allow non-invasive quantification of perfusion. Using continuous ASL, CBF was quantified for the whole rat brain under normocapnic and hypercapnic conditions. Increased cerebrovascular resistance and decreased vascular reactivity to CO2 were observed in adult SHR, confirming that hypertension leads to reduced compliance of the cerebral vasculature. The dynamic ASL technique allowed the measurement of functional CBF evoked by somatosensorial stimulation. Hypertensive rats not only showed positive hemodynamic response to stimulation, but also negative hemodynamic response in areas surrounding the positively activated areas. It was shown to be related to a purely hemodynamic effect caused by high blood pressure and impaired vascular reserve of the SHR. Pharmacological experiments showed differences on modulation of the neurovascular coupling in SHR when compared to normotensive rats. Moreover, hypertensive rats subjected to temporary middle cerebral artery occlusion had larger ischemic lesion volume and brain edema, severe decrease in body weight and worse neurological deficits, when compared to normotensive rats. These results are related to the altered cerebral autoregulation and impaired collateral circulation development in SHR. Taken together, the findings of the present work show that hypertension results in impaired vascular reserve, which is related to altered neurovascular coupling and worse stroke outcome.
83

The influence of nutrition labeling on food packaging : A qualitative marketing research on healthier purchasing decisions by Millennials influenced by front-of-pack nutrition labeling

van den Bosch, Rose Joline January 2020 (has links)
Background:                Diseases caused by nutrition-related factors are globally increasing. Consumers can use help making healthier food choices. Nutrition labeling, front-of-pack, in particular, is reviewed as an important policy tool to assist consumers in this matter. Research found that front-of-pack nutrition labeling is influencing consumer’s product choice but no study researched the influence on Millennials while they are the most interesting consumer group of these times due to their large size and increasing power.   Purpose:                  Explore how Front-Of-Package Nutrition Labeling (FOPNL) is influencing Millennials to make healthier food purchasing decisions.   Method:                       To attain the purpose, a qualitative study was conducted. A theoretical framework was created to evaluate excising factors related to FOPNL that are influencing consumer purchasing behaviour. To create in-depth insights on the influence of front-of-package nutrition labeling on Millennials, 18 semi-structured interviews have been conducted.   Conclusion:                 The results show that the influence of FOPNL on Millennials is dependant of the type of label. Currently, the main problem concerning all FOPNL types is the lack of believability of these claims, which makes them less influential on Millennial purchasing behavior. Even though, interpretive nutrient-specific claims are perceived as the most influential FOPNL type. Additionally, the influence varies depending on trial or repeat purchase.
84

Effects of antibody labeling chemistry on assays developed for the Gyrolab immunoassay platform

Dencker, Julia January 2021 (has links)
The aim of this project was to make a comparison of the effects of antibody labeling chemistries on assays developed for the Gyrolab immunoassay platform. One of the labeling techniques was a heterogenous labeling technique targeting amino groups on the antibody. The other labeling technique was a site-specific labeling technique targeting the conserved Fc-glycan at the aspargine 297 residue on the IgG molecule. The site-specific labeling was performed using a kit from Genovis called GlyCLICK. The two labeling techniques were compared on four different assays developed for the Gyrolab platform. The assays tested in this project were two anti-drug antibody assays, a pharmacokinetics assay, a polyclonal antibody assay, and a monoclonal antibody assay. The drug tolerance was tested for the anti-drug antibody assays, resulting in better drug tolerance for reagents labeled with amino conjugation for the Humira assay with incubation overnight. A confirmatory analysis, testing the inhibition of negative control with addition of unlabeled drug in the Master Mix, was performed. This resulted in small differences in the inhibition between the different reagents, except for Keytruda on Gyrolab Bioaffy 200, for which the GlyCLICK labeled reagents led to a lower inhibition of the negative control. For all the assays the effects on signal to background ratio and limit of detection was investigated. The greatest advantages of GlyCLICK on the signal to background was observed for anti-drug antibody Keytruda assay and polyclonal antibody assay. For the polyclonal antibody assay, the results indicated potentially reduced need for the polishing step and for two wash solutions after addition of the detect reagent.
85

Studying the Temporal Dynamics of the Gut Microbiota Using Metabolic Stable Isotope Labeling and Metaproteomics

Smyth, Patrick 29 June 2021 (has links)
The gut microbiome and its metabolic processes are dynamic systems. Surprisingly, our understanding of gut microbiome dynamics is limited. Here we report a metaproteomic workflow that involves protein stable isotope probing (protein-SIP) and identification/quantification of partially labeled peptides. We also developed a package, which we call MetaProfiler, that corrects for false identifications and performs phylogenetic and time series analysis for the study of microbiome dynamics. From the stool sample of five mice that were fed with 15-N hydrolysate from Ralstonia eutropha, we identified 15,297 non-redundant unlabeled peptides of which 10,839 of their heavy counterparts were quantified. These peptides revealed incorporation profiles over time that were different between and within taxa, as well as between and within clusters of orthologous groups (COGs). Our study helps unravel the complex dynamics of protein synthesis and bacterial dynamics in the mouse gut microbiome.
86

Preprodynorphin-Expressing Neurons Constitute a Large Subgroup of Somatostatin-Expressing GABAergic Interneurons in the Mouse Neocortex / マウス大脳新皮質ソマトスタチン陽性抑制性細胞の約半数は、プレプロダイノルフィンを発現する

Sohn, Jaerin 23 March 2016 (has links)
The version posted must include the following notice on the first page: This is the peer reviewed version of the following article: http://onlinelibrary.wiley.com/doi/10.1002/cne.23477/abstract, which has been published in final form at DOI: 10.1002/cne.23477. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. / 京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第19610号 / 医博第4117号 / 新制||医||1015(附属図書館) / 32646 / 京都大学大学院医学研究科医学専攻 / (主査)教授 渡邉 大, 教授 髙橋 良輔, 教授 宮本 享 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
87

The Effect of Menu Nutrition Labels on Consumers' Dietary Decision Making

Lowe, Diane M 01 January 2012 (has links) (PDF)
To help combat the growing obesity problem in the United States, the Menu Labeling Act was passed in 2010 as part of the Patient Protection and Affordable Care Act. However, little research has been conducted to determine the optimal format and content of the imminent label. A between-subjects experiment was conducted with a non-probability sample that was provided with three nutrition label treatments and surveyed to determine the labels’ effect on accuracy in dietary judgments and nutrition evaluations, level of certainty and confusion while completing those tasks, and perceived label comprehension and utility. The presence of a label had a positive relationship with all the dependent measures, while the addition of percent daily values to the label had a nonsignificant increase in accuracy but a negative effect on confusion and comprehension.
88

The Relationship Between the Availability of Non-Calorie Nutrition Information at the Point of Purchase and an Individual's Food Purchasing Behavior at Chain Restaurants in King County, Washington

Faehr, Aleesha M. 11 October 2013 (has links)
No description available.
89

PART 1. SYNTHESIS OF STABLE-ISOTOPE LABELED AMINO ACIDS PART 2. SYNTHESIS OF MECHANISTIC PROBES OF RETINOID ACTION

Barnett, Derek W. 20 December 2002 (has links)
No description available.
90

A qualitative analysis of calorie menu labeling: Point of sale conversations with cashiers at fast-casual retsaurants

Bechtel, Kimberly 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / The study was conducted to examine the communication between the customer and the cashier at the point of purchase in the process of determining the impact of the labeling laws. This study used an inductive qualitative design for data collection and data analysis. Data from this study suggest that calorie counts on menu labels are discussed frequently between the customer and the cashier at the point of sale at fast-casual restaurants. The data found gives us a framework and rationale as to why previous research on the effectiveness of the calorie labeling law in the Affordable Care Act have yet to make a significant impact in reducing consumer’s total daily caloric intake when eating food away from the home and found three specific reasons as to why the calorie labeling law may not be working the way the government intended it to. First, consumers at fast-casual restaurants rely on the cashiers as calorie guides because they are not aware or knowledgeable about the recommended daily caloric intake and often underestimate the total calories in their meals. Secondly, the study’s findings indicate that when restaurants offer lower calorie choices and downsizing options like a “small pita” at Pita Pit instead of a “regular pita”, many consumers buy the downsized item or smaller portion but food chains are not downsizing their signature items. Third, the study examined if the cashiers are trained in any way to discuss new regulations and calorie count/nutritional value and not one cashier was trained specifically about the calorie labeling law and why certain foods on the menu have more calories than others even though they are influencing decision making. Conversations at the point of sale have been routinely ignored in research about the calorie labeling law and this research helps to understand the choices consumers are making with the newly implemented calorie labeling regulation. The results from this study helps us further advance our understanding as to why consumers make the food choices they do while eating at restaurants.

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