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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.
541

The Northern IRA and the early years of partition 1920-22

Lynch, Robert John January 2003 (has links)
The years i 920-22 constituted a period of unprecedented conflct and political change in Ireland. It began with the onset of the most brutal phase of the War ofIndependence and culminated in the effective miltary defeat of the Republican IRA in the Civil War. Occurring alongside these dramatic changes in the south and west of Ireland was a far more fundamental conflict in the north-east; a period of brutal sectarian violence which marked the early years of partition and the establishment of Northern Ireland. Almost uniquely the IRA in the six counties were involved in every one of these conflcts and yet it can be argued was on the fringes of all of them. The period i 920-22 saw the evolution of the organisation from a peripheral curiosity during the War of independence to an idealistic symbol for those wishing to resolve the fundamental divisions within the Sinn Fein movement which developed in the first six months of i 922. The story of the Northern IRA's collapse in the autumn of that year demonstrated dramatically the true nature of the organisation and how it was their relationship to the various protagonists in these conflcts, rather than their unceasing but fruitless war against partition, that defined its contribution to the Irish revolution.
542

Fluorine and chlorine fractionation in the sub-arc mantle : an experimental investigation / Fractionemment du fluor et du chlore dans le manteau sub-arc : une approche expérimentale

Dalou, Célia 21 January 2011 (has links)
Les éléments volatils libérés de la plaque plongeante lors de la subduction jouent un rôle fondamental durant la formation des magmas d'arc dans le coin mantellique. Depuis quelques années, les développements des techniques d'analyse par sonde ionique ont permis l'analyse de ces éléments, en particulier F et Cl, dans les magmas d'arc, et notamment dans les magmas d'arc primaires grâce aux avancées des études sur les inclusions magmatiques. Une récente étude des inclusions magmatiques du Mont Shasta (E. U.) (Le Voyer et al., 2010) a montré que le fractionnement du F et du Cl apportait des informations sur la genèse des magmas d'arc. Afin de caractériser la source de ces magmas, j'ai étudié les coefficients de partage du fluor et du chlore. Dans cette étude, je présente les premiers coefficients de partage du F et du Cl, entre des liquides de fusions silicatés anhydres et hydratés et des minéraux mantelliques tels que olivine, orthopyroxène, clinopyroxène, plagioclase, grenat ainsi que pargasite et phlogopite. Les valeurs sont issues de 300 mesures dans 24 expériences de fusion, réalisées entre 8 et 25 kbars et, 1180 et 1430˚C. Les faibles concentrations en F et Cl dans les minéraux ont été analysées par la sonde ionique Cameca IMF 1280 de WHOI en utilisant le mode d'ions secondaires négatifs. Les résultats montrent que DOpx/meltF varient de 0.123 à 0.021 et DCpx/meltF de 0.153 à 0.083, tandis que DOpx/meltCl varient de 0.002 à 0.069 et DCpx/meltCl de 0.008 à 0.015. De plus, DOl/meltF de 0.116 à 0.005 et DOl/meltCl de 0.001 à 0.004 ; DGrt/meltF de 0.012 à 0.166 et DGrt/meltCl de 0.003 à 0.087 avec l'augmentation de la teneur en eau et la diminution de la température dans les expériences. Je montre aussi que le F est compatible dans la phlogopite (DPhl/meltF >1.2) alors qu'il est incompatible dans la pargasite (DAmp/meltF de 0.36 à 0.63). A l'inverse, Cl est plus incompatible dans la phlogopite (DPhl/meltCl en moyenne 0.09±0.02), que dans la pargasite (DAmp/meltCl de 0.12 à 0.38). Cette étude démontre que F et Cl sont substitués dans des sites spécifiques de l'oxygène, ce qui les rend plus sensibles que les éléments traces aux variations de chimie des cristaux et de la quantité d'eau, et donc aux conditions de fusion. En utilisant ces nouveaux coefficients de partage, j'ai modélisé la fusion de lithologies potentielles du manteau sub-arc permettant de 1) déterminer la quantité de fluide aqueux impliqué dans la fusion, 2) distinguer la fusion induite par apport de fluides de la fusion d'une source à minéraux hydratés et 3) la fusion d'une lithologie à pargasite de celle à phlogopite, et montre que la source de certains magmas primaires d'arc, par exemple d'Italie, contient de la pargasite et de la phlogopite, tandis d'autres magmas primaires d'arc résultent d'une fusion par apport de fluides. / Volatile elements released from the subducting slab play a fundamental role during the formation of arc magmas in the mantle wedge. Advances of melt inclusion studies enlarged the data on volatile abundance in arc magmas, and it is now possible to characterize some volatile contents in arc primary magmas, in particular F and Cl. A recent study of Mt Shasta melt inclusions (LeVoyer et al., 2010) shows that fractionation of F and Cl potentially contains information about arc magma genesis. In order to trace the source of arc magmas, fluorine and chlorine partitioning was investigated. Here, I present new experimental determinations of Cl and F partition coefficients between dry and hydrous silicate melts and mantle minerals: olivine, orthopyroxene, clinopyroxene, plagioclase, garnet and also pargasite and phlogopite. The values were compiled from more than 300 measurements in 24 melting experiments, conducted between 8 and 25 kbars and between 1180 and 1430˚C. The low abundance F, Cl measurements in minerals were done by Cameca IMF 1280 at WHOI using the negative secondary ion mode. The results show that DOpx/meltF ranges from 0.123 to 0.021 and DCpx/meltF ranges from 0.153 to 0.083, while Cl partition coefficient varies from DOpx/meltCl from 0.002 to 0.069 and DCpx/meltCfrom 0.008 to 0.015, as well. Furthermore, DOl/meltF ranges from 0.116 to 0.005 and DOl/meltCl from 0.001 to 0.004; DGrt/meltF ranges from 0.012 to 0.166 and DGrt/meltCl from 0.003 to 0.087 with the increasing water amount and decreasing temperature. I also show that F is compatible in phlogopite DPhl/meltF > 1.2) while DAmp/meltF is incompatible in pargasite DAmp/meltF from 0.36 to 0.63). On the contrary, Cl is more incompatible in phlogopite (DPhl/meltCl > 1.2 on average 0.09 ± 0.02), than in pargasite (DPhl/meltCl from 0.12 to 0.38). This study demonstrates that F and Cl are substituted in specific oxygen site in minerals that lead then to be more sensitive than trace elements to crystal chemistry and water amount variations thus melting conditions. Using those new partition coefficients, I modelled melting of potential sub-arc lithologies with variable quantity aqueous-fluid. This model is able to decipher 1) amount of aqueous-fluid involved in melting, 2) melting induced by fluid or melting of an hydrous mineral-bearing source and 3) melting of either pargasite-bearing lithology or phlogopite-bearing lithology and shows that sources of some primitive melts, for instance from Italy, bear pargasite and phlogopite, while some primitve melts seem to be the results of fluid-induced melts.
543

Jordan, Palestine and the British world system, 1945-57 : Glubb Pasha and the Arab Legion

Jevon, Graham January 2014 (has links)
This thesis offers a microcosmic insight into Britain's transition toward a world system without an Empire by exploring the life of the Anglo-Jordan Treaty (1946-57) via the prism of the British financed Jordanian Army, also known as the Arab Legion, and its British commander, Glubb Pasha. In so doing it puts the state of the relationship down to a system of mutual dependence. Britain's withdrawal from Jordan has primarily been linked either to the success of Arab nationalism or the loss of British will. By examining the Treaty relationship from construction to termination this thesis posits that it is imprudent to push any single factor too deeply, but identifies a shift in the balance of mutual dependence, caused by the changing geopolitical climate, as the driving force. A subsidiary aspect of this thesis concerns the partition of Palestine. The Arab Legion was the most important Arab army during the 1948 War. Based on unprecedented access to Glubb's private papers 'the most significant new documents to emerge since the opening of the official western archives in the late 1970s' this thesis provides the most accurate portrayal of the Arab Legion's conduct yet achievable. In so doing it reconciles inconsistencies within the controversial 'collusion' debate. It negates the revisionist argument that a firm Hashemite-Zionist agreement existed, but corroborates the notion that Britain approved the Arab Legion's use to implement an alternative form of partition to that proposed by the UN. It thus supports the revisionist argument that pre-war negotiations helped shape the 1948 War, but explains the Arab Legion's adherence to this secret scheme by emphasising Glubb's (limited) autonomy. Moreover, it reveals further details concerning the divisions within the Arab coalition, which further debunks the traditional David (Israel) versus Goliath (Arab coalition) portrayal of the conflict.
544

Contribution à la caractérisation des précurseurs d’arôme glycosylés du bois de chêne / Contribution to the characterization of oak wood glycosylated aroma precursors

Slaghenaufi, Davide 13 December 2012 (has links)
La présence d’un métabolisme actif des bactéries lactiques dans le vin logé en fûts de chêne induit une augmentation de la concentration des composés volatils du bois. Ce phénomène a récemment été attribué à l'activité glycosidique des bactéries. Le glucoside précurseur d'un composé majeur de l’arôme boisé (whiskylactone) a déjà été identifié et quantifié dans le bois de chêne. Mais aucune donnée n'était disponible jusqu’à présent concernant l’identification formelle des précurseurs pour d’autres arômes du bois de chêne.Un premier travail a permis de montrer que les précurseurs monoglycosides n'existaient pas dans le bois de chêne, dans les spiritueux et dans le vin. L'étude a été réalisée à l’aide de la technique UPLC-FT/MS, en utilisant la vanilline-β-D-glucopyranoside, la vanilline-β-D-xylopyranoside, et la coniféraldéhyde-β-D-glucopyranoside, synthétisées par réaction par transfert de phase. Dans un deuxième temps, une purification des précurseurs glycosidiques complexes a été réalisée à l’aide de la Chromatographie de Partage Centrifuge (CPC) à partir d’un extrait de bois de chêne. Le choix du système de solvants a été basé sur une égale répartition dans les deux phases de la libération d’arômes par hydrolyse enzymatique. Cela a conduit à la détermination du nouveau concept de coefficient de partage d’activité Kca. Après purification et fractionnement, la vanilline galloylglucoside, le triméthoxyphénol-galloyl-glucoside et le macarangioside E ont été isolés du bois et identifiés par HPLC-ESI-MS et RMN. Ces précurseurs ont été quantifiés dans différentes espèces de chêne par HPLC-QqQ-MS. Ces trois composés sont les précurseurs respectivement de la vanilline, du 3,4,5-triméthoxyphénol et du 3-oxo-α-ionol. Par dégradation thermique, le macarangioside E peut conduire à la mégastigmatriénone et à la 4-oxo-isophorone, dont les notes aromatiques sont le tabac et l’encens. Ces composés complètent la connaissance que nous avons de l’arôme boisé du vin et contribuent ainsi à une meilleure compréhension de la genèse du bouquet tertiaire. / The presence of lactic acid bacteria (LAB) in oak barrels induces an increase in wood volatile compounds concentration. This phenomenon could be due to the glycosidic activity of LAB. The glucosidic precursor of a major woody aroma compound (oak lactone) was identified and quantified in oak wood but no data was available concerning the presence of other flavor precursors in oak wood. This study showed that monoglycosidic precursors did not exist in oak, in spirits and in wines. The study was performed by UPLC-FT/MS, using vanillin-β-D-glucopyranoside, vanillin-β-D-xylopyranoside, and coniferaldehyde-β-D-glucopyranoside as standards. These molecules were synthesized by phase transfer reaction. Purification of a vanillin glycoside precursor was done by centrifugal partition chromatography (CPC). The choice of the solvent system was based on an equal distribution in both phases of the aromas released by enzymatic hydrolysis. This led to the determination of the new concept, the activity partition coefficient Kca. After purification and fractionation, vanillin galloylglucoside, trimethoxyphenol-galloylglucoside and macarangioside E were isolated from wood and identified by HPLC-ESI-MS and NMR analysis. These precursors were quantified in different oak species by HPLC-QqQ-MS. These three compounds are precursors of vanillin, 3,4,5-trimethoxyphenol and 3-oxo-α-ionol respectively. The macarangioside E can lead by thermal degradation, to megastigmatrienone and 4-oxo-isophorone which have aromatic notes of tobacco and incense. These compounds are involved in the woody aroma of the wine and the genesis of the bouquet.
545

Aspectos metabólicos, nutricionais e produtivos de cultivares de Brachiaria e Panicum visando eficiência no uso do nitrogênio / Metabolic, nutritional and production aspects of Brachiaria and Panicum cultivars aiming nitrogen use efficiency

Garcez, Tiago Barreto 01 October 2013 (has links)
O melhor entendimento sobre os aspectos metabólicos, nutricionais e produtivos das gramíneas forrageiras quanto ao uso do nitrogênio é necessário para aumentar a eficiência de uso do nutriente e para a sustentabilidade da produção pecuária. Com isso, objetivou-se analisar alguns cultivares de gramíneas forrageiras utilizados em pastagens no Brasil, quanto a: I) modificações morfológicas e produtivas da parte aérea e das raízes; II) formas de partição do nitrogênio absorvido para melhorar a eficiência de uso do nitrogênio e III) forma de assimilação do nitrogênio absorvido, sendo avaliados pelas variáveis: produção de massa seca, números de folhas e perfilhos, área foliar, concentração e conteúdos de nitrogênio total, nitrato e amônio, eficiência de uso do nitrogênio, atividades das enzimas nitrato redutase e glutamina sintetase e concentração de aminoácidos livres totais na parte aérea e nas raízes dessas gramíneas, quando submetidas a alta e baixa dose de nitrogênio. Na baixa dose de nitrogênio os cultivares Marandu, Xaraés, Piatã, Basilisk e Mombaça mantiveram o número de perfilhos constante e diminuíram o número de folhas e a área foliar, enquanto o cultivar Tanzânia manteve o número de perfilhos e área foliar constantes e reduziu o número de folhas e os cultivares Aruana e Massai aumentaram o número de perfilhos e de folhas e reduziram a área foliar. A baixa dose de nitrogênio resultou em proporções da massa seca da parte aérea e das raízes distintas entre os cultivares quando comparada à alta dose de nitrogênio, favorecendo o crescimento das raízes. Os cultivares estudados modificaram a partição de nitrogênio, nitrato e amônio da parte aérea e raízes, quando em alto e baixo suprimento de nitrogênio. Essas diferenças refletiram na mais alta eficiência de uso do nitrogênio pelos cultivares Mombaça e Tanzânia. A assimilação do nitrato ocorreu principalmente na parte aérea desses capins. Os cultivares Mombaça e Aruana apresentaram elevadas atividades da enzima nitrato redutase nas folhas diagnósticas. A atividade da enzima glutamina sintetase nas folhas diagnósticas foi mais elevada nos cultivares de Panicum. A concentração de amônio nas raízes foi mais alta nos cultivares Piatã e Xaraés, na baixa dose de nitrogênio, e nos capins Aruana e Mombaça, na dose alta de nitrogênio. A concentração de aminoácidos totais nas folhas diagnósticas foi mais elevada nos cultivares de Panicum, quando submetidos à alta dose de nitrogênio, enquanto nas raízes foi maior nos cultivares de Brachiaria, nas duas doses de nitrogênio. / A better understanding of the metabolic, nutritional and production aspects of nitrogen use by grasses are needed to increase nutrient use efficiency and livestock production sustainability. Thus, this study aimed to analyze some forage grasses cultivars used in Brazilian pastures, for: i) morphological and production changes in shoots and roots; II) absorbed nitrogen partition to improve nitrogen use efficiency and III) nitrogen assimilation, evaluated by the variables: dry matter production, number of leaves and tillers, leaf area, concentration and content of total nitrogen, nitrate and ammonium, nitrogen use efficiency, nitrate reductase and glutamine synthetase activities and free amino acids concentration in shoots and roots of these grasses, when supplied with high and low nitrogen rates. At low nitrogen rate, Marandu, Xaraés, Piatã, Basilisk and Mombaça cultivars kept the number of tillers constant and decreased the number of leaves and leaf area, while Tanzânia cultivar kept the number of tillers and leaf area constant and reduced the number of leaves, and Aruana and Massai cultivars increased the number of tillers and leaves and reduced leaf area. The low nitrogen rate resulted in different shoots to roots proportions among cultivars when compared to the higher nitrogen rate, which favored roots growth. The cultivars changed the partition of nitrogen, nitrate and ammonium between roots and shoots, in both nitrogen rates. These differences reflect the higher nitrogen use efficiency by Mombaça and Tanzânia cultivars. The nitrate assimilation occurred mainly in the shoots of these grasses. Mombaça and Aruana cultivars showed high nitrate reductase activity in diagnostic leaves. The glutamine synthetase activity in diagnostic leaves was higher in Panicum cultivars. Ammonium concentration in the roots was high in Piatã and Xaraés, at low nitrogen rate, and Aruana and Mombaça grasses, at high nitrogen rate. The total amino acids concentration in diagnostic leaves was higher in Panicum cultivars than in Brachiaria cultivars, when high nitrogen rate was supplied, whereas Brachiaria cultivars had this concentration high in the roots, at the two nitrogen rates.
546

Estudo de sistema micelares em misturas de água/acetonitrila / Studies micellar systems in mixtures of water/acetonitrile

Yihwa, Chang 18 August 2000 (has links)
Neste trabalho, estudou-se o efeito da adição de acetonitrila nas propriedades de micelas do detergente aniônico, dodecil sulfato de sódio (SDS), e do detergente catiônico, cloreto de hexadeciltrimetilamônio (CTACl). Medidas de condutividade foram utilizadas para determinar a concentração micelar crítica, cmc, e o grau de dissociação, α, das micelas em função da fração molar de acetonitrila, XAc. Medidas de supressão de fluorescência, resolvida no tempo, com pireno como sonda, foram utilizadas para determinar a influência de acetonitrila no número de agregação das micelas, N, e na dinâmica de migração de solutos entre as fases aquosa e micelar. Em baixas frações molares XAc < 0,2), a acetonitrila insere-se nas cavidades da água, quebrando parcialmente as pontes de hidrogênio da água com a formação de novas pontes de hidrogênio entre as moléculas de acetonitrila e as moléculas de água. Nesta faixa de concentração, ocorre um aumento da cmc e do α, acompanhada de uma diminuição de N. Observa-se também alterações na dinâmica da interação de contra-íons e co-íons supressores na micela. Assim, as micelas de SDS e CTACl formadas em misturas acetonitrila-água são menores, mais dissociadas e apresentam maior fluidez interna. Ao redor de XAc = 0,2, as misturas de água-acetonitrila tornam-se microheterogêneos com o aparecimento de microdomínios ricos em acetonitrila e microdomínios ricos em água. A proporção das regiões ricas em acetonitrila aumenta com o aumento da fração molar de acetonitrila, com apenas pequenas modificações das propriedades dos dois tipos de microdomínios. Em XAc > 0,2 a variação de cmc e de α com a XAc passa a ser menos acentuada, sugerindo que o detergente forma agregados preferencialmente nas regiões mais aquosas; a sonda fluorescente pireno começa sair das micelas durante o tempo de vida do estado excitado; e há claras mudanças na dinâmica de incorporação de íons nos agregados. / This work presents a study of the effect of added acetonitrile on the properties of the micelles of the anionic detergent sodium dodecylsulfate (SDS) and the cationic detergent hexadecyltrimethylammonium chloride (CTACl). Conductimetric measurements were employed to determine the critical micelle concentration, cmc, and the degree of counterion dissociation, α, of the micelles as a function of the mole fraction of added acetonitrile, XAc. Time resolved fluorescence quenching measurements with pyrene as probe were employed to determine the effect of acetonitrile on the micellar aggregation number, N, and the dynamics of solute migration between the micellar and aqueous phases. At low mole fractions (XAc < 0.2), acetonitrile inserts into the cavities present in liquid water, partially disrupting the hydrogen bonding of water, with formation of new hydrogen bonds between water and acetonitrile. In this range, both the cmc and α increase, while N decreases. The dynamics of incorporation of counterionic and coionic quenchers into the micelles is also altered. Thus, the SDS and CTACl micelles formed in these acetonitrile-water mixtures are smaller, more highly dissociated and internally more fluid than those in aqueous solution. Above XAc of ca. 0,2, acetonitrile-water mixtures become microheterogeneous, the solution containing microdomains rich in acetonitrile and microdomains rich in water. The proportion of acetonitrile-rich microdomians increases with increasing XAc, with only small changes in the properties of the two types of microdomains. Correspondingly, at XAc > > ca. 0.2: the variation of the cmc and α with XAc is much less pronounced, suggesting that the detergent forms aggregates preferentially in the aqueous-rich domains; the fluorescence probe pyrene begins to exit the micelles during its excited state lifetime; and there are distinct changes in the rate constants for the incorporation of ions into the micelles.
547

Construção dos números reais via cortes de Dedekind / Construction of the real numbers via Dedekind cuts

Pimentel, Thiago Trindade 03 September 2018 (has links)
O objetivo desta dissertação é apresentar a construção dos números reais a partir de cortes de Dedekind. Para isso, vamos estudar os números naturais, os números inteiros, os números racionais e as propriedades envolvidas. Então, a partir dos números racionais, iremos construir o corpo dos números reais e estabelecer suas propriedades. Um corte de Dedekind, assim nomeado em homenagem ao matemático alemão Richard Dedekind, é uma partição dos números racionais em dois conjuntos não vazios A e B em que cada elemento de A é menor do que todos os elementos de B e A não contém um elemento máximo. Se B contiver um elemento mínimo, então o corte representará este elemento mínimo, que é um número racional. Se B não contiver um elemento mínimo, então o corte definirá um único número irracional, que preenche o espaço entre A e B. Desta forma, pode-se construir o conjunto dos números reais a partir dos racionais e estabelecer suas propriedades. Esta dissertação proporcionará aos estudantes do Ensino Médio, interessados em Matemática, uma formação sólida em um de seus pilares, que é o conjunto dos números reais e suas operações algébricas e propriedades. Isso será muito importante para a formação destes alunos e sua atuação educacional. / The purpose of this dissertation is to present the construction of the real numbers from Dedekind cuts. For this, we study the natural numbers, the integers, the rational numbers and some properties involved. Then, based on the rational numbers, we construct the field of the real numbers and establish their properties. A Dedekind cut, named after the German mathematician Richard Dedekind, is a partition of the rational numbers into two non-empty sets A and B, such that each element of A is smaller than all elements of B and A does not contain a maximum element. If B contains a minimum element, then the cut represents this minimum element, which is a rational number. If B does not contain a minimal element, then the cut defines a single irrational number, which \"fills the gap\" between A and B. In this way, one can construct the set of real numbers from the rationals and establish their properties. This dissertation provides students who like Mathematics a solid basis in one of the pillars of Mathematics, which is the set of real numbers and their algebraic operations and properties. This text will be very important for your educational background and performance.
548

A Robinson Wiggler for the Metrology Light Source

Tydecks, Tobias 22 November 2016 (has links)
Im Jahre 1958, schlug Kenneth W. Robinson die Nutzung eines Korrektormagneten vor um den entdämpften radialen Betatronoszillationen im Cambridge electron accelerator entgegen zu wirken. Dieser Korrektormagnet sollte aus kurzen, alternierenden Dipolen mit einem starken Gradienten bestehen, sodass die Verluste durch Synchrotronstrahlung mit zunehmendem Trajektorienradius abnehmen. Diese Transversal-Gradienten-Wiggler werden auch "Robinson Wiggler" (RW) genannt. Die Metrology Light Source (MLS), welche Eigentum der Physikalisch-Technischen Bundesanstalt (PTB) ist und vom Helmholtz-Zentrum Berlin (HZB) entworfen und betrieben wird, ist ein Elektronen-Synchrotron, optimiert für die Produktion von Synchrotronstrahlung im Spektralbereich zwischen THz und EUV. Da die MLS eine gerampte Maschine ist, nimmt der gespeicherte Elektronenstrom mit der Zeit ab und die Strahllebensdauer ist von Bedeutung für die Nutzer der Synchrotronstrahlung. Es wird vorgeschlagen einen RW bei der MLS zu installieren um die Strahllebensdauer zu erhöhen. Mit RW wäre es möglich, Dämpfung aus der longitudinalen in die horizontale Ebene zu verschieben sodass sich die Energiebreite um einen Faktor 3 erhöht und die Emittanz sich um ungefähr einen Faktor 2 reduziert. Die Länge der Elektronenpakete wird dadurch stärker verlängert als die mittlere horizontale Paketbreite reduziert wird. So nimmt die Elektronendichte im Paket ab und die Verlustrate sinkt. Dies hat zu Folge dass sich die Lebensdauer verbessert und die Aktivierung von Komponenten reduziert wird. Mit erhöhter Energiebreite und verringerter Emittanz, wird der Beitrag der Dispersion zur horizontalen Quellgröße stärker. Durch geeignete Wahl der Magnetoptik kann die Brillianz am Quellpunkt erhöht werden bei gleichzeitiger Verbesserung der Lebensdauer. Simulationen zeigen dass die Lebensdauer an der MLS durch die Installation eines solchen RW um einen Faktor 2.3 ansteigt, was einem Zugewinn an integriertem Photonenfluss von 30 % entspricht. / In 1958, Kenneth W. Robinson proposed the usage of a magnetic correction device to reduce the antidamping of radial betatron oscillations in the Cambridge electron accelerator. The essence of this correction device are short, alternating dipoles with a strong gradient, such that the radiation loss decreases with increasing radius of trajectory. These transverse gradient wigglers are also called "Robinson Wigglers" (RW). The Metrology Light Source (MLS), owned by the Physikalisch-Technische Bundesanstalt (PTB) and designed and operated by Helmholtz-Zentrum Berlin (HZB), is an electron synchrotron, optimized for the production of synchrotron radiation in the THz to the EUV spectral region. Being a ramped machine, Top-Up operation is not possible. With a decaying beam current, the lifetime of the stored beam is of importance for the user community, for reasons of temporal stability and integrated photon flux. It is proposed to install a RW at the MLS in order to improve the beam lifetime. With a RW, it is possible to transfer damping from the longitundinal to the horizontal plane in a way, that the energy spread increases by a factor of 3 and the emittance reduces by a factor of 2. Doing so, the bunch length is increased by a larger fraction than the average bunch width is decreased. Thereby the electron density is reduced which results in a lower loss rate of electrons. This improves the beam lifetime and reduces induced radioactivity of accelerator components and shielding. With an increased energy spread and a reduced emittance, the contribution of the dispersion to source size becomes more important. By carefully choosing the magnet optics, the brilliance at the source point can be improved simultaneously to increasing the lifetime. Simulations indicate that a RW is able to increase the lifetime in the standard user operation mode at the MLS by a factor of 2.3, corresponding to an increase in photon flux for one standard user run of approximately 30 %.
549

Relação quantitativa entre a estrutura química e o bloqueio da transmissão neuromuscular para série de brometos de [2-(4-benzamido)etil] benzildimetilamônio para-substituídos / Quantitative relationship between chemical structure and neuromuscular transmission blockade for series of [2- (4-benzamido) ethyl] benzyldimethylammonium bromide for para-substituted

Siqueira, Leonardo José Amaral de 07 December 2001 (has links)
Neste trabalho foi preparada uma série de onze brometo de 2-[(4-X-benzamido) etil]benzildimetilamônio, compostos I.1-I.11, série I, estruturalmente análogos à procainamida, não descritos na literatura. Os valores do coeficiente de partição, log Papp7.40, destes compostos foram determinados pelo método shake-flask e foram utilizados como parâmetro lipofílico experimental. Os valores de deslocamento químico do grupamento carbonila, δ 13 C=O, foram determinados e foram determinados cm um espectrómetro de ressonância magnética nuclear a 75 MHz. Adicionalmente, outros parâmetros físico-químicos foram retirados da literatura: π, σp, Τ, R e MR4 ou obtidos por cálculo: log Pcalc e πexp. Os valores da concentração inibitória média (IC50) capaz de reduzir a contração máxima a 50% no período de 15 minutos, foram determinados em preparações nervo frênico-músculo diafragma de camundongos. Para verificar a natureza e a contribuição relativa dos parâmetros físico-químicos frente ao bloqueio da transmissão neuromuscular foi feito uma análise de QSAR, obtendo-se equações, usando análise de regressão linear. As análises de QSAR sugerem uma dependência positiva da lipofilicidade para o bloqueio da transmissão neuromuscular expresso por pIC50, segundo o modelo proposto expresso pela equação: (Ver arquivo PDF). / In this work, a set of eleven 2-[(4-X-benzamido)ethyl]benzyl dimethylammonium bromide structurally related to procainamide was synthesized. The apparent partition coefficient values were determined by means of \"shake-flask method and were taken as lipophilic parameters. The carbonyl chemical shifts values were determined in methanol-d4 and taken as electronic parameters. Additionally, physicochemical parameters were either taken from literature: π, σp, Τ, R e MR4 or calculated: log Pcalc and πexp. The median inhibitory concentration values (IC50) able to reduce maximal contraction to 50% at 15 minutes was determined in phrenic nerve-diafragm muscle preparation of mices. In order to verify the nature and relative contribution of the physicochemical parameters to neuromuscular blockage, QSAR equations were derived using regression analysis. The obtained QSAR model, expressed by the equation below, suggest that lipophilicity term plays an important role to neuromuscular blockage. (See files PDF).
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Estudo comparativo de parâmetros hipidrofóbicos e, relacionados à ionização, de série de derivados da procaína com atividade bloqueadora neuromuscular / Comparative study of the hydrophobic and ionization parameters of a series of procaine derivatives with neuromuscular blocking activity

Malvezzi, Alberto 13 March 2003 (has links)
O estudo das Relações Quantitativas entre Estrutura química e Atividade biológica (QSAR/QSAR-3D) utilizando diferentes estratégias metodológicas complementares, aplicadas iterativamente, se estende a diferentes áreas de aplicação. Dentre elas destaca-se o planejamento racional de novos fármacos e o estudo de seus mecanismos de ação. Moléculas candidatas a fármacos, geradas em estudos de QSAR-3D, freqüentemente, não se tomam fármacos por apresentarem inadequadas propriedades farmacocinéticas, ou seja, ADME (absorção, distribuição, metabolismo e excreção). Nota-se assim que o conhecimento das propriedades farmacocinéticas de ligantes deve ser uma preocupação presente, em qualquer nível de desenvolvimento de um novo fármaco e ressalta-se a importância do QSAR como uma ferramenta de grande valor, principalmente na compreensão da contribuição das propriedades físico-químicas, identificadas como sendo responsáveis pela atividade. A aplicação do QSAR permite elucidar a natureza e a grandeza das propriedades físico-químicas e estruturais nas interações entre o composto e o seu alvo biológico nos processos farmacocinéticos de ADME (TESTA, 2001; MALVEZZI et al.,, 2001; GAVIRAGHI et al., 2001). Recentemente, em trabalhos realizados em nosso laboratório (SIQUEIRA, 2001), envolvendo a análise de QSAR aplicada aos valores do bloqueio da transmissão neuromuscular determinados para uma série de onze brometos de [2-(4-X-benzamido)etil]benzildimetilamônio substituídos, demonstrou-se tanto a importância da presença de um grupo catiônico terminal como da lipofilicidade para o bloqueio da transmissão neuromuscular. No presente trabalho, visando descrever as interações hidrofóbicas determinantes da potencial atividade bloqueadora neuromuscular, para uma série de dez derivados da procaína, sendo eles: cloretos de 3-(dimetilamino)propiofenona (composto 1); de 3-(dietilamino)propiofenona (composto 2); de 3-(1-pirrolidino)propiofenona (composto 3); de 3-(1-piperidino)propiofenona (composto 4); de 3-(1-morfolino)propiofenona (composto 5); de 3-[1-(4-metilpiperazino)] propiofenona (composto 6); de 3-(c-hexilamino)propiofenona (composto 7); de N-[(N,N-dimetilamino)etil]benzamida (composto 8); de N-[(N,N-dimetilamino )metil]benzamida (composto 9) e, de N-[(N,N-dimetilamino)etil]benzoato (composto 10), por nós sintetizados, determinaram-se os respectivos parâmetros hidrofóbicos e relacionados à ionização (logPappSF; logPnSF; logPiSF; (pKaaq)SF; (pKaoct)SF; logPappHPLC; IogPnPot; IogPiPot; (pKaaq)Pot; logPcalc) obtidos por três métodos experimentais (por Shake-flask; por HPLC e potenciométrico) e por cálculo (programa CLOGP), como modelos de partição. Através da análise comparativa dos valores dos parâmetros hidrofóbicos e relacionados à ionização para a série de dez derivados da procaína (compostos 1-10) sintetizados neste trabalho foi possível constatar que: (i) os valores de IogPcalc modelam, apenas, parcialmente as interações hidrofóbicas refletidas nos valores de logPappSF e de logPappHPLC em valores de pH 3,0 e 10,0, enquanto que as interações hidrofóbicas refletidas nos valores de logPnPot são idealmente modeladas pelos valores de logPcalc; (ii) nas mesmas condições experimentais, os métodos Shake-flask, HPLC e potenciométrico revelam interações hidrofóbicas proporcionais, entretanto, correlações não ideais foram observadas quanto comparados entre si; (iii) os valores de pKaSF , determinados indiretamente por Shake-flask, foram validados pela determinação direta de pKaPot, por potenciometria. Embora o sistema de avaliação da bloqueadora da transmissão neuromuscular tenha sido adequado, a série de compostos estudada não gerou valores válidos para a construção das correspondentes curvas dose-resposta. Os valores obtidos de lC50 para os compostos 3, 4 e 8 da série estudada foram insuficientes, em número, para serem utilizados em uma análise de QSAR. Estudos futuros podem ser realizados com o objetivo de verificar a atividade anestésica local para os compostos da série estudada, avaliando-se a perda da sensibilidade à estimulação sensorial, em cobaias, ou em estudos mais sofisticados de eletrofisiologia (patch clamp). Poder-se-á, assim, fornecer subsídios para elucidar as contribuições relativas da forma catiônica e da forma neutra, respectivamente de compostos ionizáveis com atividade anestésica local. / The scope of Quantitative Structure and Biological Activity Relationships (QSAR/QSAR-3D) studies, using distinct complementary methods, spreads over multiple areas of applicability. Among those, striking are the rational design of new drugs and the enlightenment of their mechanism of action. Candidate molecules, shaped by QSAR-3D analysis, frequently fail to become drugs, and hit the market, due to insufficient pharmacokinetic properties (i.e. absorption, distribution, metabolism and excretion; ADME). Hence, the awareness of pharmacokinetic properties of molecules should be a concern at any leveI of development of new drug candidates. Noteworthy is the use of QSAR as a tool of great value, specially, in the comprehension of the contribution of the physical-chemical properties, responsible for the biological activity. (TESTA, 2001; MALVEZZl et ai., 2001; GAVlRAGHl et ai., 2001). ln this work, aiming to describe the hydrophobic interactions determining the neuromuscular blocking activity of a series of ten procaine derivatives: the hydrochlorides of 3-(dimethylamine)propiophenone (compound 1); of 3-(diethylamine)propiophenone (compound 2); of 3-(1-pirrolidine)propiophenone (compound 3); of 3-(1-piperidine)propiophenone (compound 4); of 3-(1-morfoline)propiophenone (compound 5); of 3-[1-(4-methylpiperazine)]propiophenone (compound 6); de 3-(c-hexilamine)propiophenone (compound 7); de N-[(N,N-dimethylamine)ethyl]benzamide (compound 8); de N-[(N,N-dimethylamine)methyl]benzamide (compound 9) and, of N-[(N,N-dimethylamine)ethyl]benzoate (compound 10), prepared by us, the corresponding hydrophobic parameters (logPappSF; logPnSF; logPiSF; (pKaaq)SF; (pKaoct)SF; logPappHPLC; IogPnPot; IogPiPot; (pKaaq)Pot; logPcalc) were obtained by three experimental methods (Shake-flask; HPLC and potenciometric) and by calculus (CLOGP) as models of partition and distribution. Following the comparative analysis of the values of the hydrophobic parameters determined for the ten compounds of the series of procaine analogs, it was possible to conclude that: (i) the values of IogPcalc reflect only partially, the hydrophobic interactions encoded in the values of logPappSF and logPappHPLC determined in pH values of 3,0 and 10,0; (ii) the values of logPcalc reflect the hydrophobic interactions encoded in the values of logPnPot; (iii) in the same experimental conditions, the methods Shake-flask, HPLC and potenciometric, reflect proportional hydrophobic interactions, although the observed correlations were not ideal when the methods were compared between each other; (iv) the values of pKaSF, determined indirectly by Shake-flask, were validated by the direct measurement of pKaPot, by potentiometry. Even though the system used to measure the neuromuscular blocking actions was adequate, the series of procaine derivatives failed to provide sufficient values to prepare dose-effect curves and proceed with the quantitative structure activity relationships.

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