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The Global ETD Search service is a free service for researchers
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Ressonância paramagnética eletrônica e espectroscopia de infravermelho aplicada no estudo de amidos irradiados / Electronic paramagnetic resonance and infrared spectroscopy applied in the study of irradiated starchesSilva, Gilberto Dias da 13 September 2017 (has links)
O amido é o mais abundante dos polissacarídeos de armazenamento de energia de plantas, usualmente depositado na forma de grânulos no citoplasma das células. Também é a principal fonte de energia para o homem, compondo 80-90% dos polissacarídeos da dieta humana, e é o principal responsável pelas propriedades tecnológicas que caracterizam grande parte dos produtos processados. O presente trabalho teve como objetivo a aplicação da ressonância paramagnética eletrônica (RPE) e espectroscopia de Infravermelho por transformada de Fourier (FTIR) ao estudo de amidos irradiados. Amostras em pó de dois amidos naturais, batata (bulbo) e milho (cereal) e farinha de mandioca fermentada ou polvilho azedo (raiz) foram submetidos à ação da radiação ionizante de fonte de 60Co Gammacell 220 com doses de 10, 20 e 30 kGy, taxa de dose de 1kGy h-1. Foram registrados e comparados os espectros de RPE dos três tipos de amidos irradiados e não irradiados. Os amidos apresentaram espectros de RPE semelhantes variando apenas na intensidade do sinal de radicais livres que acompanhou o incremento da dose. Foram estabelecidas as curvas de decaimento para cada um dos amidos ensaiados. No caso de amido de batata o decaimento do sinal apresentou excepcionalmente um comportamento linear quando a dose utilizada foi de 20 kGy. Foi obtido de maneira experimental o valor do fator g, que variou de 2,06062 a 1,94661, sendo o valor teórico g = 2,0023. Foram também estabelecidas as modificações radioinduzidas na estrutura molecular das amostras através da análise dos espectros de absorção no infravermelho por FTIR. / Starch is the most abundant plant energy storage polysaccharide, usually deposited in the form of granules in the cytoplasm of cells. It is also the main source of energy for man, making up 80-90% of polysaccharides in the human diet, and is mainly responsible for the technological properties that characterize most processed products. The present work aimed to the application of electronic paramagnetic resonance and Fourier Transform Infrared Spectroscopy to the study of irradiated starches. Powdered samples of two natural starches, potato (bulb) and corn (cereal) and fermented cassava flour or sour cassava (root) were subjected to the action of ionizing radiation from a 60Co Gammacell 220 at doses of 10, 20 and 30 kGy, dose rate of 1kGy h-1. The electronic paramagnetic resonance spectra of the three types of irradiated and non-irradiated starches were recorded and compared. The starches showed similar electronic paramagnetic resonance spectra varying only in the intensity of the free radical signal that accompanied the dose increase. The decay curves were established for each of the tested starches. In the case of potato starch, signal decay showed an exceptionally linear behavior when the dose used was 20 kGy. The value of factor g was obtained experimentally, ranging from 2.06062 to 1.94661, with the theoretical value g = 2.0023. The radioinduced modifications in the molecular structure of the samples were also established by the analysis of the infrared absorption spectra by Fourier Transform Infrared Spectroscopy.
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Ressonância paramagnética eletrônica e espectroscopia de infravermelho aplicada no estudo de amidos irradiados / Electronic paramagnetic resonance and infrared spectroscopy applied in the study of irradiated starchesGilberto Dias da Silva 13 September 2017 (has links)
O amido é o mais abundante dos polissacarídeos de armazenamento de energia de plantas, usualmente depositado na forma de grânulos no citoplasma das células. Também é a principal fonte de energia para o homem, compondo 80-90% dos polissacarídeos da dieta humana, e é o principal responsável pelas propriedades tecnológicas que caracterizam grande parte dos produtos processados. O presente trabalho teve como objetivo a aplicação da ressonância paramagnética eletrônica (RPE) e espectroscopia de Infravermelho por transformada de Fourier (FTIR) ao estudo de amidos irradiados. Amostras em pó de dois amidos naturais, batata (bulbo) e milho (cereal) e farinha de mandioca fermentada ou polvilho azedo (raiz) foram submetidos à ação da radiação ionizante de fonte de 60Co Gammacell 220 com doses de 10, 20 e 30 kGy, taxa de dose de 1kGy h-1. Foram registrados e comparados os espectros de RPE dos três tipos de amidos irradiados e não irradiados. Os amidos apresentaram espectros de RPE semelhantes variando apenas na intensidade do sinal de radicais livres que acompanhou o incremento da dose. Foram estabelecidas as curvas de decaimento para cada um dos amidos ensaiados. No caso de amido de batata o decaimento do sinal apresentou excepcionalmente um comportamento linear quando a dose utilizada foi de 20 kGy. Foi obtido de maneira experimental o valor do fator g, que variou de 2,06062 a 1,94661, sendo o valor teórico g = 2,0023. Foram também estabelecidas as modificações radioinduzidas na estrutura molecular das amostras através da análise dos espectros de absorção no infravermelho por FTIR. / Starch is the most abundant plant energy storage polysaccharide, usually deposited in the form of granules in the cytoplasm of cells. It is also the main source of energy for man, making up 80-90% of polysaccharides in the human diet, and is mainly responsible for the technological properties that characterize most processed products. The present work aimed to the application of electronic paramagnetic resonance and Fourier Transform Infrared Spectroscopy to the study of irradiated starches. Powdered samples of two natural starches, potato (bulb) and corn (cereal) and fermented cassava flour or sour cassava (root) were subjected to the action of ionizing radiation from a 60Co Gammacell 220 at doses of 10, 20 and 30 kGy, dose rate of 1kGy h-1. The electronic paramagnetic resonance spectra of the three types of irradiated and non-irradiated starches were recorded and compared. The starches showed similar electronic paramagnetic resonance spectra varying only in the intensity of the free radical signal that accompanied the dose increase. The decay curves were established for each of the tested starches. In the case of potato starch, signal decay showed an exceptionally linear behavior when the dose used was 20 kGy. The value of factor g was obtained experimentally, ranging from 2.06062 to 1.94661, with the theoretical value g = 2.0023. The radioinduced modifications in the molecular structure of the samples were also established by the analysis of the infrared absorption spectra by Fourier Transform Infrared Spectroscopy.
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Monitoring géochimique de la géosphère et l'atmosphère : application au stockage géologique du CO2 / Geochemical monitoring of Geosphere and Atmosphere : Application to geological storage of CO2Taquet, Noémie 21 December 2012 (has links)
Cette thèse touche à la problématique des échanges de gaz aux interfaces entre la géosphère, la biosphère, l'hydrosphère et l'atmosphère par l'intermédiaire du monitoring géochimique des gaz appliqué aux sites de stockage géologiques du CO2. Au niveau de l'axe « Métrologie », nous avons développé une plate-forme de monitoring géochimique continu, in situ et déportée par spectrométrie FTIR/Raman pour la mesure des gaz du sol (CO2, CH4, N2, O2, H2O). Des protocoles de quantification ont été développés pour la mesure par télédétection infrarouge terrestre en mode passif du CO2, CH4, SO2, H2S dans l'atmosphère. Au niveau des axes « Monitoring » et « Modélisation », les mesures de gaz du sol à proximité du puits d'injection de Rousse (Pilote CO2 Total, Lacq/Rousse, France) sur plus de sept cycles saisonniers ont montré une anti-corrélation entre la teneur en CO2 et les variations du niveau piézométrique de la nappe. Cette relation a permis de modéliser l'enveloppe de variabilité « naturelle » de la teneur en CO2 dans le sol, qui constitue un élément clé pour la surveillance des sites de stockage. Les variations majeures de teneur en CO2 sont attribuées à des processus de dissolution/libération de CO2 par la nappe, jouant un rôle de pompe à CO2. La concentration en CO2 en surface (+1m) serait gouvernée par les variations de teneur en CO2 du sol. Les mesures par télédétection FTIR des gaz dans l'atmosphère ont permis d'établir pour la première fois une simulation expérimentale 3D des enveloppes de CO2 à l'aplomb du site d'injection. Ces résultats constituent un premier pas vers la mise en place d'un outil de surveillance des panaches gazeux dans l'atmosphère / This study is based on the problematic of gas exchanges at the interface between the geosphere, biosphere, hydrosphere and atmosphere through the geochemical monitoring of gas applied to CO2 geological storage sites. Concerning the "Metrological" aspect, we developed and implemented an in situ continuous geochemical monitoring station, based on coupling FTIR/ Raman spectrometry for measuring soil gas (O2, N2, CO2, CH4 and H2O) close to the injection wells of Rousse 1 (CCS Total pilot, Lacq-Rousse, France). We also developed protocols to identify and quantify CO2, CH4, SO2, H2S in the atmosphere (plume) by passive remote sensing FTIR. On the "Monitoring" and "Modelling" aspects, the continuous recording of soil CO2 concentration during more than 7 seasonal cycles indicate that CO2 concentration in the soil was anti-correlated with changes in piezometric level of the groundwater. This correlation was used to model the limits of natural variability of CO2 content in the soil, which is a key to CCS sites monitoring. The main fluctuations in soil CO2 content was assigned to a dissolution/release process of CO2 by the perched water table, acting as a CO2 pump. The CO2 concentration at the near surface (+ 1 m) would be governed by changes of the soil CO2 content. FITR remote sensing measurement of atmospheric gases allowed for the first time to perform an experimental 3D simulation of CO2 layers on the injection site. This type of experimental simulation is a first step for the monitoring of gases in the atmosphere
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Multidisniplinary study of Alzheimer's disease-related peptides : from amyloid precursor protein (APP) to amyloid β-oligomers and γ-secretase modulators / Étude pluridisciplinaire de peptides liés à la maladie d'Alzheimer : de la protéine précurseur de l'amyloïde (APP) aux oligomères de bêta-amyloïde et aux inhibiteurs de gamma-sécrétaseItkin, Anna 14 May 2012 (has links)
Une des caractéristiques histopathologiques de la maladie d'Alzheimer (AD) est la présence de plaques amyloïdes formées par les peptides amyloïdes β (Aβ) de 40 et 42 résidus, qui sont les produits de clivage par des protéases de l'APP. Afin de comprendre le rôle des variations structurelles du TM dans le traitement de l'APP, les peptides APP_TM4K ont été étudiés dans la bicouche lipidique en utilisant l’ATR-FTIR et ssNMR. Tandis que la structure secondaire globale du peptide APP_TM4K est hélicoidale, hétérogénéité de conformation et d'orientation a été observée pour le site de clivage γ et , que peuvent avoir des implications dans le mécanisme de clivage et donc dans la production d’Aβ. Les peptides Aβ s'agrègent pour produire des fibrilles et aussi de manière transitoire d'oligomères neurotoxiques. Nous avons constaté qu'en présence de Ca2+, l’Aβ (1-40) forme de préférence des oligomères, tandis qu'en absence de Ca2+ l'Aβ (1-40) s’agrège sous forme de fibrilles. Dans les échantillons sans Ca2+, l’ATR-FTIR révèle la conversion des oligomères en feuillets β antiparallèles en la conformation caractéristique des fibrilles en feuillets β parallèles. Ces résultats nous ont amené à conclure que les Ca2+ stimulent la formation d'oligomères d'Aβ (1-40), qui sont impliqués dans l’AD. Les positions et une orientation précise de deux nouveaux médicaments puissants modulateurs de la γ-sécrétase - le benzyl-carprofen et le sulfonyl-carprofen dans la bicouche lipidique, ont été obtenus à partir des expériences des ssNMR. Ces résultats indiquent que le mécanisme probable de modulation du clivage par la y-sécrétase est une interaction directe avec le domaine TM de l’APP. / A histopathological characteristic of Alzheimer’s disease (AD) is the presence of amyloid plaques formed by amyloid β(A) peptides of 40 and 42 residues-long, which are the cleavage products of APP by proteases. To understand the role of structural changes in the TM domain of APP, APP_TM4K peptides were studied in the lipid bilayer using ATR-FTIR and ssNMR. While the overall secondary structure of the APP_TM4K peptide is helical, conformational and orientational heterogeneity was observed for the y- and for the -cleavage sites, which may have implications for the cleavage mechanism and therefore the production of Aβ. Starting from its monomeric form, Aβ peptides aggregate into fibrils and / or oligomers, the latter being the most neurotoxic. We found that in the presence of Ca2 +, Aβ (1-40) preferably forms oligomers, whereas in the absence of a2 + Aβ (1-40) aggregates into fibrils. In samples without Ca2 +, ATR-FTIR shows conversion from antiparallel β sheet conformation of oligomers into parallel β sheets, characteristic of fibrils. These results led us to conclude that Ca2 +stimulates the formation of oligomers of Aβ (1-40), that have been implicated in the pathogenesis of AD. Position and precise orientation of two new drugs powerful modulators of γ-secretase benzyl-carprofen and carprofen sulfonyl in the lipid bilayer were obtained from neutron scattering and ssNMR experiments. These results indicate that carprofen-derivatives can directly interact with APP. Such interaction would interfere with proper APP-dimer formation, which is necessary for the sequential cleavage by β -secretase, diminishing or greatly reducing Aβ42 production.
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Challenges and potentials of channeling local philanthropy towards development and aocial justice and the role of waqf (Islamic and Arab-civic endowments) in building community foundationsDaly, Marwa El 16 May 2012 (has links)
Diese Arbeit bietet eine solide theoretische Grundlage zu Philanthropie und religiös motivierten Spendenaktivitäten und deren Einfluss auf Wohltätigkeitstrends, Entwicklungszusammenarbeit und einer auf dem Gedanken der sozialen Gerechtigkeit beruhenden Philanthropie. Untersucht werden dafür die Strukturen religiös motivierte Spenden, für die in der islamischen Tradition die Begriffe „zakat“, „Waqf“ oder im Plural auch „awqaf-“ oder „Sadaqa“ verwendet werden, der christliche Begriff dafür lautet „tithes“ oder „ushour“. Aufbauend auf diesem theoretischen Rahmenwerk analysiert die qualitative und quantitative Feldstudie auf nationaler Ebene, wie die ägyptische Öffentlichkeit Philanthropie, soziale Gerechtigkeit, Menschenrechte, Spenden, Freiwilligenarbeit und andere Konzepte des zivilgesellschaftlichen Engagements wahrnimmt. Um eine umfassende und repräsentative Datengrundlage zu erhalten, wurden 2000 Haushalte, 200 zivilgesellschaftliche Organisationen erfasst, sowie Spender, Empfänger, religiöse Wohltäter und andere Akteure interviewt. Die so gewonnen Erkenntnisse lassen aussagekräftige Aufschlüsse über philanthropische Trends zu. Erstmals wird so auch eine finanzielle Einschätzung und Bewertung der Aktivitäten im lokalen Wohltätigkeitsbereich möglich, die sich auf mehr als eine Billion US-Dollar beziffern lassen. Die Erhebung weist nach, dass gemessen an den Pro-Kopf-Aufwendungen die privaten Spendenaktivitäten weitaus wichtiger sind als auswärtige wirtschaftliche Hilfe für Ägypten. Das wiederum lässt Rückschlüsse zu, welche Bedeutung lokale Wohltätigkeit erlangen kann, wenn sie richtig gesteuert wird und nicht wie bislang oft im Teufelskreis von ad-hoc-Spenden oder Hilfen von Privatperson an Privatperson gefangen ist. Die Studie stellt außerdem eine Verbindung her zwischen lokalen Wohltätigkeits-Mechanismen, die meist auf religiösen und kulturellen Werten beruhen, und modernen Strukturen, wie etwa Gemeinde-Stiftungen oder Gemeinde-„waqf“, innerhalb derer die Spenden eine nachhaltige Veränderung bewirken können. Daher bietet diese Arbeit also eine umfassende wissenschaftliche Grundlage, die nicht nur ein besseres Verständnis, sondern auch den nachhaltiger Aus- und Aufbau lokaler Wohltätigkeitsstrukturen in Ägypten ermöglicht. Zentral ist dabei vor allem die Rolle lokaler, individueller Spenden, die beispielsweise für Stiftungen auf der Gemeindeebene eingesetzt, wesentlich zu einer nachhaltigen Entwicklung beitragen könnten – und das nicht nur in Ägypten, sondern in der gesamten arabischen Region. Als konkretes Ergebnis dieser Arbeit, wurde ein innovatives Modell entwickelt, dass neben den wissenschaftlichen Daten das Konzept der „waqf“ berücksichtigt. Der Wissenschaftlerin und einem engagierten Vorstand ist es auf dieser Grundlage gelungen, die Waqfeyat al Maadi Community Foundation (WMCF) zu gründen, die nicht nur ein Modell für eine Bürgerstiftung ist, sondern auch das tradierte Konzept der „waqf“ als praktikable und verbürgte Wohlstätigkeitsstruktur sinnvoll weiterentwickelt. / This work provides a solid theoretical base on philanthropy, religious giving (Islamic zakat, ‘ushour, Waqf -plural: awqaf-, Sadaqa and Christian tithes or ‘ushour), and their implications on giving trends, development work, social justice philanthropy. The field study (quantitative and qualitative) that supports the theoretical framework reflects at a national level the Egyptian public’s perceptions on philanthropy, social justice, human rights, giving and volunteering and other concepts that determine the peoples’ civic engagement. The statistics cover 2000 households, 200 Civil Society Organizations distributed all over Egypt and interviews donors, recipients, religious people and other stakeholders. The numbers reflect philanthropic trends and for the first time provide a monetary estimate of local philanthropy of over USD 1 Billion annually. The survey proves that the per capita share of philanthropy outweighs the per capita share of foreign economic assistance to Egypt, which implies the significance of local giving if properly channeled, and not as it is actually consumed in the vicious circle of ad-hoc, person to person charity. In addition, the study relates local giving mechanisms derived from religion and culture to modern actual structures, like community foundations or community waqf that could bring about sustainable change in the communities. In sum, the work provides a comprehensive scientific base to help understand- and build on local philanthropy in Egypt. It explores the role that local individual giving could play in achieving sustainable development and building a new wave of community foundations not only in Egypt but in the Arab region at large. As a tangible result of this thesis, an innovative model that revives the concept of waqf and builds on the study’s results was created by the researcher and a dedicated board of trustees who succeeded in establishing Waqfeyat al Maadi Community Foundation (WMCF) that not only introduces the community foundation model to Egypt, but revives and modernizes the waqf as a practical authentic philanthropic structure.
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