Proefschrift Maastricht. / Lit. opg. - Met samenvatting in het Nederlands.

Proefschrift Universiteit Maastricht. / Auteursnaam op omslag: Lico Hoekema. Met bibliogr., lit. opg. - Met samenvatting in het Nederlands.

Thesis (MA)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

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Made available in DSpace on 2018-08-01T22:29:31Z (GMT). No. of bitstreams: 1 tese_4549_Dissertação Paulo Maciel.pdf: 6344610 bytes, checksum: fd8f862339be640c5a3eeb2c82490c57 (MD5) Previous issue date: 2010-03-22 / Este estudo exploratório mostra resultados sobre a investigação da utilização do "V" Epistemológico de Gowin em uma disciplina de Física Experimental na graduação em Física da Universidade Federal do Espírito Santo. Para o desenvolvimento desse estudo foi estruturada a implantação do "V" de Gowin na disciplina Física Experimental I para as modalidades Educador/Licenciatura e Pesquisador/Bacharelado do Currículo Novo do Curso de Física da UFES. Foi utilizado um roteiro sobre o uso do "V"de Gowin em Física Experimental e os roteiros das experiências realizadas na disciplina. Os estudantes produziram um "V" de Gowin para cada experimento, com o objetivo de explicitar a estrutura do experimento, ou seja, quais são as Questões Básicas de Pesquisa referentes aos objetivos da experiência; em que consiste o Domínio Conceitual, ou seja, os Princípios & Leis, as Hipóteses e os Conceitos envolvidos na experiência; quais são os Eventos realizados para as promover observações e coletas de dados do experimento; qual é o Domínio Metodológico utilizado, isto é, quais são os Registros dos Eventos, as Transformações necessárias, os Resultados dessas Transformações e as Interpretações possíveis a partir desses Resultados; quais são as Respostas as Questões Básicas de Pesquisa proposta e; qual a relevância dessas Respostas e de todo o experimento estudado. Para analisar os "V"s de Gowin produzidos utilizaram-se critérios de avaliação baseados em par^ametros que valorizam a articulac~ao dos aspectos do "V". Com a conclus~ao do estudo, foi possvel analisar as habilidades e di-culdades apresentadas pelos estudantes com a implantac~ao do\V"de Gowin em Fsica Experimental. Tambem foi possvel indicar contribuic~oes para os roteiros entregues aos estudantes na disciplina Fsica Experimental. E -nalmente, foi realizada uma analise sobre os criterios de avaliac~ao utilizados nesse estudo.

Velocity-difference induced focusing (V-DIF) with a dynamic pH junction in capillary electrophoresis (CE) using a sample with a pH different from that of the background electrolyte (BGE) was developed in our group, but the mechanism was not well understood. In this work, the mechanism of this focusing technique was first studied using an appropriate dye to monitor the pH of the BGE and the sample during the focusing process. A mechanism was proposed based on the experimental results. This technique was then applied to serotonin to improve the detection limit when CE was used with a UV absorption detector. It was also applied to focus amino acids, peptides, and proteins to improve the concentration sensitivity. It is found that the pKa rather than the pI of the analytes is the key criterion for selecting the pH for the sample and for the BGE to obtain the optimum focusing for these molecules. Since UV detection only provides migration time information, more structure information is obtained by using a photodiode array (PDA) and mass spectrometer (MS) for peak identification. Comparisons were made between the PDA detection and MS detection for aromatic amino acids with V-DIF using a dynamic pH junction. This V-DIF technique was then applied to non-aromatic amino acids with MS detection. It was used at low pH with positive ESI-MS detection and at high pH with negative ESI-MS ionization. The results of the two methods were compared and discussed. Finally, the preparative operation of continuous flow counterbalanced CE (FCCE) was studied. The effects of larger sample volumes and multiple capillary systems on improving the purification yield were investigated. / Science, Faculty of / Chemistry, Department of / Graduate

This paper develops a stochastic model for the growth of two interacting populations: when one species preys upon the other. The spatial distribution of the populations is considered, that of the prey being assumed to be clustered and quasi-uniform. This latter distribution is discussed in some detail, and it is found that, although it has been suggested that clustering of the prey may be a protective device against predators, any differences in the stochastic models for clustered and unclustered populations lie only in the constant coefficients involved in the formulation of the model. The approach used in developing the proposed model is that of Chiang. The size of the prey and predator populations; are assumed to be random variables X(t) and Y(t) respectively, and certain assumptions are made concerning the birth-rate and death-rate In either population. These assumptions are based on the deterministic equations (formula omitted). These equations are modifications of equations published by Leslie in 1958. Differential equations are developed for the rate of change of the probability that X(t)=x and Y(t)=y, by giving transition probabilities in some small interval of time and letting the interval shrink to a point. Hence differential equations, for the rate of change of the joint probability generating function of X and Y, and for the rate of change of the joint factorial moments of X and Y are obtained. Because of the complicated nature of these equations, however, no attempt is made to solve them. / Science, Faculty of / Mathematics, Department of / Graduate

Boston University. University Professors Program Senior theses. / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-02

Master's Thesis "Restructuring of Technistone, a.s. company" is pursuits two main aims: to analyze Technistone's initial financial situation including identification of its causes and to propose the remedy solution. As a primary method for analyzing data are used standard methods of financial analysis. The remedy solution is based on the combination of the results of the financial analysis and used in practice concept of change management above crisis conditions -- "V Concept". Thesis conclusion lies in discovering of insolvency of Technistone, a.s. company. The proposed solution mainly consists in the debt reorganization.

O processo de biomineralização óssea é a deposição de cristais de fosfato de cálcio, na forma de hidroxiapatita formando o tecido ósseo. São mediados pelas vesículas da matriz (MVs) que são liberadas no local específico do início da biomineralização. As MVs contêm altas concentrações de íons Ca2+ e fosfato inorgânico (Pi), proporcionando um microambiente adequado para a formação inicial e propagação dos cristais de hidroxiapatita. Para que isso ocorra corretamente são necessárias diversas proteínas/enzimas, bem como microambientes com condições específicas. Neste trabalho uma atenção especial foi dada a duas proteínas presentes nas MVs: Anexina V (AnxA5) e a nucleotídeo pirofosfatase/fosfodiesterase-1 (NPP1). A Anexina V é responsável pela formação de um canal de cálcio por meio da associação desta proteína tanto com a face externa quanto interna da membrana das MVs. A NPP1 possui a função principal de hidrolisar adenosina trifosfato (ATP), formando adenosina monofosfato (AMP) e pirofosfato (PPi). Assim, experimentos de expressão de Anexina V e NPP1 foram realizados com o intuito de iniciar os estudos de interação entre as duas proteínas, por meio de reconstituição em lipossomos. A expressão de Anexina V foi realizada em células E. coli BL21(DE3) e induzida por isopropil -D-1-tiogalactopiranosídeo (IPTG); para purificação, três procedimentos foram necessários, utilizando coluna de níquel, coluna Desalting e coluna de troca iônica (Mono-Q). Experimentos de dicroísmo circular foram realizados com amostras de Anexina V após purificação e mostraram que todas as amostras apresentavam estruturas em -hélice. Pelo método da gota pendente foi estudada a interação de Anexina V com íons Ca2+ (10 mM) em monocamadas constituídas por dipalmitoil fosfatidilcolina (DPPC) e de uma mistura de composição lipídica 9:1 de DPPC e dipalmitoil fosfatidilserina (DPPS). Os dados obtidos mostraram alta afinidade de Anexina V por monocamadas constituídas de (9:1) DPPC:DPPS na presença de íons Ca2+. A expressão de NPP1 foi realizada com transfecção por meio de eletroporação do DNA recombinante em células COS-1, e seleção com antibiótico G418 após 24 horas de cultivo. Amostras de fração de membrana controle e NPP1 recombinante foram preparadas após 60 horas de cultivo celular e foi observada atividade catalítica na amostra de fração de membrana da NPP1. Todas as amostras de expressão, tanto de Anexina V e NPP1, foram analisadas por eletroforese em gel de poliacrilamida. A padronização da Anexina V foi obtida com sucesso, porém com relação à NPP1, experimentos ainda devem ser realizados a fim de padronizar a obtenção desta proteína recombinante em quantidade suficiente para continuar os estudos. / The bone biomineralization process is the deposition of calcium phosphate crystals in the form of hydroxyapatite forming the bone tissue. They are mediated by matrix vesicles (MVs) that are released at the specific site of the onset of biomineralization. MVs contain high concentrations of Ca2+ ions and inorganic phosphate (Pi), providing a suitable microenvironment for the initial formation and propagation of hydroxyapatite crystals. To occur properly, several proteins/enzymes are needed, as well as microenvironments with very particular conditions. In this work, special attention should be given to two proteins present in the MVs: Annexin V (AnxA5) and nucleotide pyrophosphatase/ phosphodiesterase (NPP1). Annexin V is responsible for the formation of a calcium channel through the association of this protein with both the outer and the inner face of the MVs membrane. NPP1 has the main function of hydrolyzing adenosine triphosphate (ATP), adenosine monophosphate (AMP) and pyrophosphate (PPi).Thus, experiments of expression of Annexin V and NPP1 were performed with the aim of initiating the interaction studies between the two proteins, through reconstitution in liposomes. Annexin V expression was performed in E.coli BL21 (DE3) and the cells were induced by isopropyl -D-1-thiogalactopyranoside (IPTG); for purification, three procedures were required using a nickel column, a Desalting column and an ion exchange column (Mono-Q). Circular dichroism experiments were performed with Annexin V samples after purification and showed that all samples contain -helix structures. Using the pendant drop method, the interaction of Annexin V with (10 mM) Ca2+ ions was studied in monolayers composed of dipalmitoyl-phosphatidyl-choline (DPPC) and a mixture of lipid composition 9:1 DPPC and dipalmitoyl-phosphatidyl-serine (DPPS). Data showed high affinity of Annexin V by monolayers constituted of (9: 1) DPPC:DPPS in the presence of Ca2+ ions. NPP1 expression was performed with transfection by electroporation of the recombinant DNA into COS-1 cells and selection with G418 antibiotic after 24 hours of culture. Samples of the control membrane fraction and recombinant NPP1 were prepared and the activity of the membrane fraction of NPP1 was observed in the samples. All expression samples, both AnxA5 and NPP1, were analyzed by polyacrylamide gel electrophoresis. The standardization of Annexin V has been obtained with success, but regarding NPP1, experiments have yet to be performed to standardize the production of this recombinant protein and to obtain enough quantity to continue the study.