954 resultados para N-terminal Modifications


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O presente relatório de estágio está inserido no âmbito do Trabalho Final de Mestrado do perfil de Edificações, relativo ao curso de Engenharia Civil do Instituto de Engenharia de Lisboa. Foi realizado um estágio com o período de dezasseis semanas na Somague Engenharia, integrado na obra pública do Projecto de Expansão do Terminal de GNL de Sines. O documento compreende o estudo e o acompanhamento da construção dos elementos principais do terminal, nomeadamente, o novo sistema de água do mar e o tanque de armazenagem de GNL. O Capítulo 2 descreve o funcionamento e apresenta os principais sistemas constituintes do terminal. O objectivo primordial deste trabalho tem como base o estudo dos recursos e da metodologia construtiva envolvida no sistema de adução de água do mar, no tanque de armazenagem e no sistema de rejeição de água do mar, apresentando os Capítulos 3,4 e 5, respectivamente. Os Capítulos 6 e 7 desenvolvem, respectivamente, a evolução construtiva verificada durante o período de estágio e os trabalhos realizados enquanto estagiário. Os Capítulos 3 e 5 são complementados pelos Anexos I e II, assim como pelos Apêndices I e II, respectivamente. Os anexos são utilizados como referência para as peças desenhadas, enquanto os apêndices são utilizados para um complemento ao desenvolvimento pormenorizado de algumas soluções.

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OBJETIVO: Analisó el costo-efectividad en intervenciones para pacientes con insuficiencia renal crónica terminal (IRCT) en términos de los costos económicos de cada intervención, los años de vida ganados y la calidad de vida que generan tres alternativas comparables y mutuamente excluyentes: diálisis peritoneal contínua ambulatoria (DPCA), la hemodiálisis (HD) y el trasplante renal (TR). MÉTODO: El diseño del estudio fue de tipo longitudinal. Los costos de cada intervención se determinaron mediante la técnica de manejo de caso promedio. Las medidas para evaluar los criterios de efectividad elegidos fueron la probabilidad de sobrevida y el Año de Vida Ajustado por Calidad (QALY, Quality Adjusted Life Year) medido por el Indice de Rosser. RSULTADOS: Los costos de manejo anual de caso fueron: diálisis peritoneal $5,643.07, hemodiálisis $9,631.60 y trasplante $3,021.63. En cuanto a la efectividad, la sobrevida del injerto de trasplante renal resultó de 89,9% y 79,6% a uno y tres años respectivamente, mientras que los pacientes sometidos a DPCA tienen una sobrevida de 86,2% y 66,9% a un año y a tres años respectivamente. En cuanto a los QALY's, los resultados para cada intervención fueron: DPCA 0,879; HD 0,864; y para el TR 0,978. CONCLUSIÓN: La intervención más costo-efectiva resultó el trasplante renal con un coeficiente de 3,088.69, seguido de la DPCA y la hemodiálisis, cuyos coeficientes fueron de 6,416.95 y 11,147.68 respectivamente. Por lo tanto se recomienda promover y utilizar el trasplante renal como la intervención más costo-efectiva para pacientes con IRCT.

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A two terminal optically addressed image processing device based on two stacked sensing/switching p-i-n a-SiC:H diodes is presented. The charge packets are injected optically into the p-i-n sensing photodiode and confined at the illuminated regions changing locally the electrical field profile across the p-i-n switching diode. A red scanner is used for charge readout. The various design parameters and addressing architecture trade-offs are discussed. The influence on the transfer functions of an a-SiC:H sensing absorber optimized for red transmittance and blue collection or of a floating anode in between is analysed. Results show that the thin a-SiC:H sensing absorber confines the readout to the switching diode and filters the light allowing full colour detection at two appropriated voltages. When the floating anode is used the spectral response broadens, allowing B&W image recognition with improved light-to-dark sensitivity. A physical model supports the image and colour recognition process.

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Imidazolidin-4-ones are commonly employed as skeletal modifications in bioactive oligopeptides, either as proline surrogates or for protection of the N-terminal amino acid against aminopeptidase-catalysed hydrolysis . We have been working on the synthesis of imidazolidin-4-ones of the antimalarial primaquine , through acylation of primaquine with an α-amino acid and subsequent reaction of the resulting α-aminoamide with a ketone or aldehyde. Thus, when using racemic primaquine, an optically pure chiral α-amino acid and an aldehyde as starting materials, four imidazolidin-4-one diastereomers are to be expected (Scheme 1). However, we have recently observed that imidazolidin-4-one synthesis was stereoselective when 2-carboxybenzaldehyde (2CBA)* was used, as only two diastereomers were produced2. Computational studies have shown that the imine formed prior to ring closure had, for structures derived from 2CBA, a quasi-cyclic rigid structure2. This rigid conformation is stabilized by an intramolecular hydrogen bond involving the C=O oxygen atom of the 2-carboxyl substituent in 2CBA and the N-H group of the α-amino amide moiety2. These findings led us to postulate that the 2-carbonyl substituent in the benzaldehyde moiety was the key for the stereoselective synthesis of the imidazolidin-4-ones2.

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Native agars from Gracilaria vermiculophylla produced in sustainable aquaculture systems (IMTA) were extracted under conventional (TWE) and microwave (MAE) heating. The optimal extracts from both processes were compared in terms of their properties. The agars’ structure was further investigated through Fourier transform infrared and NMR spectroscopy. Both samples showed a regular structure with an identical backbone, β-D-galactose (G) and 3,6-anhydro-α-L-galactose (LA) units; a considerable degree of methylation was found at C6 of the G units and, to a lesser extent, at C2 of the LA residues. The methylation degree in the G units was lower for MAEopt agar; the sulfate content was also reduced. MAE led to higher agar recoveries with drastic extraction time and solvent volume reductions. Two times lower values of [η] and Mv obtained for the MAEopt sample indicate substantial depolymerization of the polysaccharide backbone; this was reflected in its gelling properties; yet it was clearly appropriate for commercial application in soft-texture food products.

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The deep-sea environment is difficult to sample, and often only small quantities of samples can be obtained when using less destructive methods than dredging. When working with marine animals that are difficult to sample and with limited quantities of tissue to extract lipids, it is essential to ensure that the used method extracts the maximum possible quantity of lipids. This study evaluates the efficiency of introducing modifications to the method originally described by Bligh & Dyer (1959). This lipid extraction method is broadly used with modifications, although these usually lack proper description and evaluation of increment in lipids. In this study we consider the improvement in terms of amount of lipids extracted by changing the method. Lipid content was determined by gravimetric measurements in eight invertebrates from the deep-sea, including deep-sea hydrothermal vents animals, using three different approaches. Results show increases of 14% to 30% in lipid contents obtained from hydrothermal vent invertebrate tissues and whole animals by placing the samples in methanol for 24 hours before applying the Bligh & Dyer mixture. Efficiency of the extractions using frozen and freeze-dried samples was also compared. For large sponges, the use of lyophilized materials resulted in increases of 3 to 7 times more lipids extracted when compared with extractions using frozen samples.

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Realization that hard coastal infrastructures support lower biodiversity than natural habitats has prompted a wealth of research seeking to identify design enhancements offering ecological benefits. Some studies showed that artificial structures could be modified to increase levels of diversity. Most studies, however, only considered the short-term ecological effects of such modifications, even though reliance on results from short-term studies may lead to serious misjudgements in conservation. In this study, a sevenyear experiment examined how the addition of small pits to otherwise featureless seawalls may enhance the stocks of a highly-exploited limpet. Modified areas of the seawall supported enhanced stocks of limpets seven years after the addition of pits. Modified areas of the seawall also supported a community that differed in the abundance of littorinids, barnacles andmacroalgae compared to the controls. Responses to different treatments (numbers and size of pits) were speciesspecific and, while some species responded directly to differences among treatments, others might have responded indirectly via changes in the distribution of competing species. This type of habitat enhancement can have positive long-lasting effects on the ecology of urban seascapes.Understanding of species interactions could be used to develop a rule-based approach to enhance biodiversity.

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Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica - Ramo Manutenção e Produção

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Relatório de Estágio para obtenção do grau de Mestre em Engenharia Civil

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A synthetic essay about portuguese Late Cretaceous (Upper Campanian-Maastrichtian) and Paleogene is presented. This does include most of the so far known data, a critical approach to the problems of such formations, and to previous works on them. Our viewpoints (party original) are exposed in a shorter text in French where most of the discussion was suppressed (see reference in Resumo).

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The synthetic study of the uppermost Cretaceous of the Beira Litoral (fauna, flora) confirms its upper Campanian-Maastrichtian age. It shows the presence of a tropical to subtropical climate in an area constituted by a low coastal plain only occasionally linked to the sea, saturated with fresh water and possessing accordingly, a predominantely freshwater fauna (Viso, Aveiro); this plain changed towards the interior into a drier more forested zone with a more abundant terrestrial fauna which includes mammals (Taveiro). A thorough study of the chelonian Rosasia, abundant on the coastal plain, was made possible thanks to the discovery of a skull: it demonstrates that the genus belongs to the family Bothremydidae, revalided here. The composition of this family is presented, its phylogenetic and paleobiogeographic relation with the other pleurodires are analyzed, and its diagnosis established. The family is constituted of three groups; Rosasia belongs to one of these, the Bothremys group.

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The reef levels of the gulf of Skoura belong to the reef formation of the Upper Miocene of the South-Rifan straits. A detailed analysis of the vertical distribution of various forms of colonies has led to the establishment of precise coral morphologies zonation. This palaeoecological approach leads us to distinguish between two environments in the Skoura gulf, probably corresponding to two reef episodes. The palaeogeographical implications (relationships between the Atlantic ocean and the Mediterranean sea) will be pointed out.

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Desilication and a combination of alkaline followed by acid treatment were applied to MCM-22 zeolite using two different base concentrations. The samples were characterised by powder X-ray diffraction, Al-27 and Si-29 MAS-NMR spectroscopy, SEM, TEM and low temperature N-2 adsorption. The acidity of the samples was study through pyridine adsorption followed by FTIR spectroscopy and by the analyses of the hydroxyl region. The catalytic behaviour, anticipated by the effect of post-synthesis treatments on the acidity and space available inside the two internal pore systems was evaluated by using the model reaction of m-xylene transformation. The generation of mesoporosity was achieved upon alkaline treatment with 0.05 M NaOH solution and practically no additional gain was obtained when the more concentrate solution, 0.1 M, was used. Instead, Al extraction takes place along with Si, as shown by Si-29 and Al-27 MAS-NMR data, followed by Al deposition as extraframework species. Samples submitted to alkaline plus acid treatments present distinct behaviour. When the lowest NaOH solution was used no relevant effect was observed on the textural characteristics. Additionally, when the acid treatment was performed on an already fragilized MCM-22 structure, due to previous desilication with 0.1 M NaOH solution, the extraction of Al from both internal pore systems promotes their interconnection, evolving from a 2-D to a 3-D porous structure. This transformation has a marked effect in the catalytic behaviour, allowing an increase of m-xylene conversion as a consequence of an easier and faster molecular traffic in the 3-D structure. On the other hand, the continuous deposition of extraframework Al species inside the pores leads to a shape selective effect that privileges the formation of the more valuable isomer p-xylene.

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia do Ambiente, perfil Gestão e Sistemas Ambientais

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Trabalho Final de Mestrado para obtenção do grau de Mestrado em Engenharia Electrónica e Telecomunicações