34 resultados para Cavity ring-up spectroscopy
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Dissertation to obtain the academic degree of Master in materials engineering submitted to the Faculty of science and engineering of Universidade Nova de Lisboa
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The initial goal of this work was the development of a supported liquid membrane (SLM) bioreactor for the remediation of vaccine production effluents contaminated with a highly toxic organomercurial – thiomersal. Therefore, two main aspects were focused on: 1) the development of a stable supported liquid membrane – using room temperature ionic liquids (RTILs) – for the selective transport of thiomersal from the wastewater to a biological compartment, 2) study of the biodegradation kinetics of thiomersal to metallic mercury by a Pseudomonas putida strain. The first part of the work focused on the evaluation of the physicochemical properties of ionic liquids and on the SLMs’ operational stability. The results obtained showed that, although it is possible to obtain a SLM with a high stability, water possesses nonnegligible solubility in the RTILs studied. The formation of water clusters inside the hydrophobic ionic liquid was identified and found to regulate the transport of water and small ions. In practical terms, this meant that, although it was possible to transport thiomersal from the vaccine effluent to the biological compartment, complete isolation of the microbial culture could not be guaranteed and the membrane might ultimately be permeable to other species present in the aqueous vaccine wastewater. It was therefore decided not to operate the initially targeted integrated system but, instead, the biological system by itself. Additionally, attention was given to the development of a thorough understanding of the transport mechanisms involved in the solubilisation and transport of water through supported liquid membranes with RTILs as well as to the evaluation of the effect of water uptake by the SLM in the transport mechanisms of water-soluble solutes and its effect on SLM performance. The results obtained highlighted the determinant role played by water – solubilised inside the ionic liquids – on the transport mechanism. It became clear that the transport mechanism of water and water-soluble solutes through SLMs with [CnMIM][PF6] RTILs was regulated by the dynamics of water clusters inside the RTIL, rather than by molecular diffusion through the bulk of the ionic liquid. Although the stability tests vi performed showed that there were no significant losses of organic phase from the membrane pores, the formation of water clusters inside the ionic liquid, which constitute new, non-selective environments for solute transport, leads to a clear deterioration of SLM performance and selectivity. Nevertheless, electrical impedance spectroscopy characterisation of the SLMs showed that the formation of water clusters did not seem to have a detrimental effect on the SLMs’ electrical characteristics and highlighted the potential of using this type of membranes in electrochemical applications with low resistance requirements. The second part of the work studied the kinetics of thiomersal degradation by a pure culture of P. putida spi3 strain, in batch culture and using a synthe tic wastewater. A continuous ly stirred tank reactor fed with the synthetic wastewater was also operated and the bioreactor’s performance and robustness, when exposed to thiomersal shock loads, were evaluated. Finally, a bioreactor for the biological treatment of a real va ccine production effluent was set up and operated at different dilution rates. Thus it was possible to treat a real thiomersal-contaminated effluent, lowering the outlet mercury concentration to values below the European limit for mercury effluent discharges.
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Dalton Trans., 2003, 3328-3338
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Dissertação apresentada para obtenção do Grau de Doutor em Engenharia Química, especialidade de Operações Unitárias e Fenómenos de Transferência, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia
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Masters Thesis – Academic Year 2007/2008 - European Master’s Degree in Human Rights and Democratization (E.MA) - European Inter-university Centre for Human Rights and Democratization (EIUC) -Faculdade de Direito, Universidade Nova de Lisboa (UNL)
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Dissertation presented to the Faculty of Sciences and Technology of New University of Lisbon in fulfilment of the requirements for the Master’s degree in Conservation and Restoration Specialization in easel painting
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Dissertation for the degree of Doctor of Philosophy in Physics
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A thesis submitted for the degree of Ph. D. in Physics
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RESUMO: A permeabilidade nasal (nasal patency) é um conceito importante na avaliação da função nasal. Pode ser explicado como uma medida do quanto a cavidade nasal está “aberta” e é determinada por fatores dependentes da sua estrutura anatómica que se relacionam com o fluxo e a resistência nasais e a existência de um fenómeno denominado ciclo nasal. Tradicionalmente, a avaliação da permeabilidade nasal baseia-se em indicadores subjetivos, nomeadamente Escalas Visuais Analógicas ou Scores de Sintomas, embora a sensação subjetiva de obstrução nasal seja difícil de quantificar e frequentemente não se correlacione com métodos mais objetivos de avaliação. A Rinometria Acústica (RA) tem adquirido um papel cada vez mais relevante na avaliação das alterações da permeabilidade nasal, pelo seu carácter não-invasivo, rápido, de fácil execução e por ser bem tolerada pelos pacientes. Contudo, não foram ainda publicados valores de referência para a população normal. Com o presente trabalho pretendeu-se determinar áreas transversais (AT) e volumes (Vol) da cavidade nasal em adultos saudáveis através de RA, em condições basais e após a administração de um fármaco descongestionante tópico nasal, relacionando estes parâmetros com variáveis demográficas e antropométricas. MATERIAL E MÉTODOS: O estudo foi realizado em 32 adultos jovens, de ambos os sexos (18 mulheres e 14 homens), com idade igual ou superior a 18 anos, não fumadores, sem patologias crónicas ou infeção recente das vias aéreas superiores. Para a execução do exame de RA foi utilizado o equipamento SRE2000 com Software RhinoScan Interacoustics, Dinamarca). O rinograma foi analisado em condições basais e após descongestionamento até aos 5 cm de distância da narina, obtendo-se os valores médios entre cavidade nasal direita e esquerda das áreas transversais (AT) dos entalhes registados (AT1 e AT2), a sua localização e volumes nasais a diferentes distâncias (Vol.0-2; Vol.2-5 e Vol.0-5). RESULTADOS: Os indivíduos do género masculino apresentaram valores significativamente superiores aos do género feminino em todos os parâmetros estudados. A administração do fármaco descongestionante tópico nasal provocou um aumento generalizado das AT e volumes nasais, traduzindo uma diminuição da congestão da mucosa nasal, mais acentuada posteriormente ao nível dos cornetos. A comparação entre fossas nasais (direita versus esquerda) após descongestionamento, eliminando o efeito do ciclo nasal, revelou simetria significativa. De uma forma geral, os parâmetros rinométricos estudados revelaram correlação positiva significativa com a altura. CONCLUSÃO: O estudo foi pioneiro para a população portuguesa e representa uma contribuição para a obtenção de valores de referência em adultos jovens. Estudos futuros em amostras de maior dimensão e representatividade são necessários para a obtenção de valores de referência com utilidade clínica e em investigação.--------------ABSTRACT: Nasal patency is an important concept in the evaluation of nasal function. It may be explained as a measure of how open the nasal cavity is, and it depends of anatomical aspects, that relate to nasal airflow, resistance and nasal cycle. Nasal patency evaluation is based in subjective indicators like visual analogical scales or symptom scores, but subjective sensation of nasal obstruction is difficult to quantify and usually doesn’t correlate with more objective methods of evaluation. Acoustic rhinometry has gained an increasingly relevant role in assessing changes in nasal patency, because it is noninvasive, fast and easy to perform and well tolerated by patients However, reference values for the normal population have not yet been published. The aim of the present study was to determine nasal cross-sectional areas and volumes in healthy adults by acoustic rhinometry, before and after administration of a topical nasal decongestant drug, correlating these parameters with demographic and anthropometric variables. MATERIAL E METHODS: The study was performed in 32 young adults (18 females and 14 males), aged 18 years old or more, non-smokers, without chronic diseases or recent airway infection. Acoustic rhinometry evaluation was performed using SRE2000 with RhinoScan software (Interacoustics, Denmark). Nasal cavities were assessed up to 5 cm distance from the nostril, before and after administration of the topical nasal decongestant drug, and mean cross-sectional areas of the notches, their location and mean volumes at different distances from nostril were measured. RESULTS: Males presented significant higher values than females for all rhinometric parameters studied. The decongestant drug, significantly increased all the rhinometric parameters evaluated, in particular those corresponding to the more posterior regions. Comparison between nasal cavities after nasal decongestion showed no significant asymmetry. Globally,a positive correlation was found between rhinometric parameters and height . CONCLUSION: This study was pioneer in the Portuguese population and represents a contribution to acoustic rhinometry reference values in young adults . Further studies, on larger and representative samples, are necessary in order to obtain reference values, useful both to clinical and research applications of this technique.
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Ligand K-edge XAS of an [Fe3S4]0 model complex is reported. The pre-edge can be resolved into contributions from the í2Ssulfide, í3Ssulfide, and Sthiolate ligands. The average ligand-metal bond covalencies obtained from these pre-edges are further distributed between Fe3+ and Fe2.5+ components using DFT calculations. The bridging ligand covalency in the [Fe2S2]+ subsite of the [Fe3S4]0 cluster is found to be significantly lower than its value in a reduced [Fe2S2] cluster (38% vs 61%, respectively). This lowered bridging ligand covalency reduces the superexchange coupling parameter J relative to its value in a reduced [Fe2S2]+ site (-146 cm-1 vs -360 cm-1, respectively). This decrease in J, along with estimates of the double exchange parameter B and vibronic coupling parameter ì2/k-, leads to an S ) 2 delocalized ground state in the [Fe3S4]0 cluster. The S K-edge XAS of the protein ferredoxin II (Fd II) from the D. gigas active site shows a decrease in covalency compared to the model complex, in the same oxidation state, which correlates with the number of H-bonding interactions to specific sulfur ligands present in the active site. The changes in ligand-metal bond covalencies upon redox compared with DFT calculations indicate that the redox reaction involves a two-electron change (one-electron ionization plus a spin change of a second electron) with significant electronic relaxation. The presence of the redox inactive Fe3+ center is found to decrease the barrier of the redox process in the [Fe3S4] cluster due to its strong antiferromagnetic coupling with the redox active Fe2S2 subsite.
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Dissertation presented to obtain the Ph.D degree in Molecular Medicine
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Dissertação Apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Ciências da Conservação, especialização em Pintura
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics