The research in this dissertation examines the chemistry and applications of dendrimers in homogeneous catalysis. We examined interactions between dendrimers and charged probe molecules, prepared dendrimer-encapsulated metal nanoparticles in organic solvents, studied size-selectivity of dendrimer-encapsulted catalysts, and designed molecular rulers as in-situ probes to measure the location of dendrimer-encapsulted metal nanoparticles. The intrinsic proton binding constant and a constant that characterizes the strength of electrostatic interactions among occupied binding sites in poly(amidoamine) (PAMAM) dendrimers have been obtained by studying the effect of solution pH on the protonation of the dendrimers. The significant finding is that these two factors are greatly modulated by the unique and hydrophobic microenvironment in the dendrimer interior. Hydrophilic poly(propylene imine) (PPI) dendrimers were modified with various hydrophobic alkyl chains through an amide linkage and were then used as templates for preparing intradendrimer copper nanoclusters. The main driving force for encapsulating metal-ions was found to be the differences in metal-ion solubility between the solvent and the interior of the dendrimer. Nanometer-sized metal particles are synthesized and encapsulated into the interior of dendrimers by first mixing together the dendrimer and metal ion solution and then reducing the composite chemically, and the resulting dendrimer-encapsulated metal nanoparticles can then be used as catalysts. By controlling the packing density on the dendrimer periphery using either different dendrimer generations or dendrimer surface functionalities, it is possible to control access of substrates to the encapsulated catalytic nanoparticle. Molecular rulers consisting of a large molecular "stopper", a reactive probe and a linker were designed as in-situ probes for determining the average distance between the surface of dendrimer-encapsulated palladium nanoparticles and the periphery of their fourth-generation, hydroxyl-terminated PAMAM dendrimer hosts. By doing so, we avoid having to make assumptions about the nanoparticle size and shape. The results suggest that the surface of the encapsulated nanoparticle is situated 0.7 ± 0.2 nm from the surface of the dendrimer.

Cuando escuchamos un sonido intenso e inesperado podemos tener una reacción de sobresalto (RS) que es común a la mayoría de mamíferos. La respuesta, que se puede dividir en varios componentes, consiste típicamente en extensión, seguida de flexión rápida de una serie de músculos. La RS no está generalmente bajo control voluntario, y se puede modificar por muchas intervenciones. Por ejemplo, tanto los humanos como las ratas tienen RS más grande cuando están asustados (Grillon et al. 1991). Este aumento se puede reducir por las medicaciones que reducen la ansiedad (Graham et al. 2005). Si se presentan estímulos en el umbral de percepción (baja intensidad) poco antes de emitir un estímulo acústico, éste produce una reducción en la reacción de sobresalto. Este efecto, conocido como inhibición por prepulso (PPI) es anormal en algunos pacientes psiquiátricos (Takahashi et al. 2008) y nos indica la existencia de circuitos subcorticales usados en el control de la RS. Por estos y otros motivos, los cambios en el tamaño de la RS son ampliamente utilizados para estudiar las sensaciones como el miedo o la ansiedad, y los efectos de información sensorial relevante.La hipótesis principal de este proyecto es que los circuitos que vehiculan la reacción de sobresalto participan en la ejecución de movimientos voluntarios balísticos en el ser humano. La ejecución rápida de un movimiento comporta una preparación motora que implica principalmente un aumento de excitabilidad en las estructuras que van a ser activadas a lo largo de la vía motora. Debido a dicho aumento de excitabilidad, impulsos que activen estructuras subcorticales con suficiente representación en el programa motor preparado pueden desencadenar la ejecución del movimiento sin necesidad de la participación de áreas motoras superiores. Esta hipótesis general se subdivide en varias hipótesis parciales, que se especifican a continuación:a) El circuito de la RS participa en la ejecución de movimientos voluntarios. Por lo tanto, la hipótesis de trabajo es que la excitabilidad del RS debería experimentar cambios temporales similares a los descritos para la excitabilidad de la vía córtico-espinal en el inicio del movimiento. b) El circuito de la RS contribuye a la preparación motora para la ejecución de movimientos balísticos. Por lo tanto, la hipótesis de trabajo es que su excitabilidad debería cambiar de acuerdo a la instrucción y al tipo de reacción. c) El efecto StartReact se debe a la participación de la vía del RS en la ejecución de movimientos balísticos y no a la adición simple de los comandos del movimiento voluntario a la RS. Por lo tanto, la hipótesis de trabajo es que el acortamiento del tiempo de reacción podría estar presente incluso cuando la RS está inhibida por la presencia de un estímulo de prepulso.d) El movimiento realizado en la condición StartReact es igual de preciso que el movimiento balístico realizado voluntariamente. Por lo tanto, la hipótesis de trabajo es que la aceleración de movimientos sacádicos mediante el fenómeno StartReact no debería suponer ningún cambio significativo en el tiempo de reacción a un estímulo imperativo presentado en la diana visual. e) El fenómeno StartReact refleja el grado de preparación motora subcortical. Por lo tanto, la hipótesis de trabajo es que el porcentaje de acortamiento en el tiempo de reacción debería disminuir en condiciones en las que se limita el grado de dicha preparación, tal como ocurre cuando el sistema motor está ocupado en la realización de un movimiento continúo.Por tanto, los objetivos de la tesis son los que se detallan a continuación:1. Estudiar el perfil temporal de los cambios de excitabilidad que ocurren en el circuito de la RS antes de la ejecución de una tarea motora. 2. Analizar si el cambio de excitabilidad pre-movimiento en el circuito de sobresalto se modifica en relación con el tipo de tarea motora en preparación. 3. Examinar si la inhibición por prepulso de la RS causa también inhibición del efecto StartReact en el contexto de una tarea simple de tiempo de reacción.4. Determinar si el efecto StartReact se observa en los movimientos sacádicos horizontales del ojo y si dicho efecto implica un movimiento de fijación de la mirada con la misma exactitud que el movimiento voluntario en sí mismo. 5. Evaluar si el retraso en el tiempo de reacción unilateral que ocurre cuando se realiza un movimiento rítmico oscilatorio con el brazo contralateral (efecto de la tarea-doble) se relaciona con una disminución en la excitabilidad del circuito de sobresalto.

The two-hit hypothesis of schizophrenia proposes that the development of the illness involves an early neurodevelopmental stress component which increases vulnerability to later stressful life events, in combination leading to overt disease. This thesis describes a two-hit animal model, comprising of an early first hit in the form of 24 hours maternal deprivation on postnatal day 9, and a late second hit simulated by 2 weeks of corticosterone administration from 8 to 10 weeks of age in rats. The project included behavioural studies on prepulse inhibition (PPI) regulation, locomotor activity, and learning and memory, and neurochemical and molecular studies on dopaminergic parameters, brain-derived neurotrophic factor (BDNF) and glucocorticoid receptor (GR) expression. / In the two-hit animals, there was little effect on baseline PPI or locomotor activity. However, the effect of acute treatment with the dopaminergic stimulants, apomorphine, amphetamine and quinpirole, was markedly diminished. There were differential effects of either maternal deprivation or corticosterone administration on the action of these drugs. However, there was no change in any of the groups in the effect of the serotonin-1A receptor agonist, 8-OH-DPAT, on PPI, or the effect of amphetamine and phencyclidine on locomotor activity. (For complete abstract open document)

Submitted by Maria Creuza Silva (mariakreuza@yahoo.com.br) on 2013-09-03T19:32:50Z No. of bitstreams: 1 Do CENDES-OPAS à programação da saúde no SUS - dissertação de Estevão - Cópia.pdf: 864439 bytes, checksum: fefeabc96347525b4a4ac3f23acf21fc (MD5) / Approved for entry into archive by Maria Creuza Silva(mariakreuza@yahoo.com.br) on 2013-09-03T19:36:47Z (GMT) No. of bitstreams: 1 Do CENDES-OPAS à programação da saúde no SUS - dissertação de Estevão - Cópia.pdf: 864439 bytes, checksum: fefeabc96347525b4a4ac3f23acf21fc (MD5) / Made available in DSpace on 2013-09-03T19:36:47Z (GMT). No. of bitstreams: 1 Do CENDES-OPAS à programação da saúde no SUS - dissertação de Estevão - Cópia.pdf: 864439 bytes, checksum: fefeabc96347525b4a4ac3f23acf21fc (MD5) Previous issue date: 2012 / Trata-se de uma dissertação de mestrado de caráter teórico sobre a programação da saúde no Sistema Único de Saúde (SUS) que objetiva sistematizar uma crítica à Programação Pactuada e Integrada (PPI) da Assistência à Saúde. O estudo toma como referência as bases teórico-metodológicas da programação em saúde na América Latina e é trabalhado por meio de análise documental e revisão bibliográfica. Divide-se em quatro partes: i) uma sistematização de elementos teóricos e metodológicos da programação da saúde na América Latina, com ênfase no chamado método CENDES-OPAS; ii) uma apresentação da Programação Pactuada e Integrada (PPI) da Assistência à Saúde, seus princípios, diretrizes e principais questões, a partir de seus documentos oficiais; iii) uma análise da PPI da Assistência à luz de questões sobre a programação em saúde surgidas originalmente como críticas ao CENDES-OPAS e iv) uma sistematização teórica sobre aspectos da programação da assistência à saúde no SUS. Dentre as conclusões do estudo podem ser apresentadas: uma importante correlação teórica entre o CENDES-OPAS e a PPI; a existência de indefinições, insuficiências e contradições conceituais e metodológicas nos documentos oficiais da PPI; a escassez da correspondência entre discurso, teoria e método no âmbito da programação da assistência à saúde no SUS; a manutenção da necessidade de teorias, métodos e instrumentos que estimulem e auxiliem a prática da programação da saúde no SUS, em sintonia com o processo do planejamento, e a concomitante fragilidade da produção teórica recente sobre o assunto. / Salvador

Nesta dissertação, foram estudados os métodos de síntese de filmes poliméricos como matrizes hospedeiras da enzima tirosinase vislumbrando o desenvolvimento de biossensores mais seletivos e duradouros na detecção de compostos fenólicos. Os polímeros utilizados e preparados por cronoamperometria em acetonitrila foram: polipirrol (PPI), polimetiltiofeno (PMET) e copolímero PPI-PMET. Os filmes PPI-PMET apresentaram características intermediárias às dos filmes PPI e PMET, conforme se verificaram em espectros na região do infravermelho (FTIR), voltametria cíclica e microscopia de força atômica (AFM), evidenciando, assim, a formação de uma nova matriz polimérica. O processo de superoxidação do filme PPI-PMET foi estudado visando a uma imobilização mais eficiente da enzima, quando se obteve uma condição na qual a superoxidação ocorre somente nas cadeias de PPI. Biossensores amperométricos foram preparados a partir do uso da tirosinase extraída do abacate como fonte enzimática por imobilização física e realizada de maneiras diferentes em filmes não superoxidados e superoxidados. Foi feita a otimização das respostas dos filmes variando-se o pH, potencial de trabalho, concentração da enzima e tempo de imobilização da enzima para a detecção de catecol. Os resultados indicaram que a superoxidação do PPI nos filmes PPI-PMET favoreceu a imobilização da enzima, embora não fosse tão eficiente quando se comparou aos filmes com o PPI não superoxidado. Contudo, os biossensores, em geral, apresentaram grande sensibilidade ao catecol, com um limite de detecção baixo, da ordem de 0,12 µmol/L. / The synthesis methods of polymer films as host matrices of the enzyme tyrosinase were studied in this dissertation. It was expected the development of selective and everlasting biosensors for the detection of phenolic compounds. The used polymers were prepared by chronoamperometry in acetonitrile as followed: polypyrrole (PPI), polymethylthiophene (PMET) and copolymer PPI-PMET. The PPI-PMET films showed intermediate characteristics as the PPI and PMET films, as observed in the infrared spectra (FTIR), cyclic voltammetry and atomic force microscopy (AFM), thus indicating the formation of a new polymeric matrix . The process of overoxidized of PPI-PMET film was studied in order to achieve a more efficient immobilization of the enzyme, whilst it was achieved a condition in which overoxidized occurs only in the PPI chain. Amperometric biosensors were prepared from the use of tyrosinase extracted from avocado as an enzyme source by physical immobilization and performed in different ways in both overoxidized and non-overoxidized films. It was performed the optimization of the responses of the films by varying pH, operacuonial potential, enzyme concentration and time in the enzyme immobilization for the detection of catechol. The results showed that the overoxidized PPI in the films PPI-PMET favored the immobilization of the enzyme, although not as efficient when compared to the films with nom overoxidized PPI. Neverthless, the catechol biosensors showed a high sensitivity with a low detection limit in the order of 0.12 µmol/L.

Nesta dissertação, a polifenol oxidase (PFO) como extrato bruto de abacate (Persea americana) foi imobilizada em filmes de polipirrol (PPI) sintetizados eletroquimicamente utilizando o glutaraldeído (GA) como um agente de ligação entrecruzada. Os filmes PPI e PPI/PFO-GA foram caracterizados por eletroquímica, principalmente voltametria cíclica, sendo avaliadas a eletroatividade e a reversibilidade eletroquímica. A detecção de compostos fenólicos em soluções padrão foi feita por cronoamperometria, tendo um controle sobre a concentração dos compostos. O processo de transferência de massa foi monitorado com uma microbalança de cristal de quartzo eletroquímica. Os resultados indicaram uma boa reprodutibilidade das medidas na detecção dos compostos fenólicos. A estabilidade do biossensor em uma solução tampão manteve-se durante 27 dias, um resultado aceitável já que é encontrado na literatura um tempo de vida estável para sistemas semelhantes em tomo de 30 dias / In this dissertation, polyphenol oxidase (PPO) as crude extract of avocado (Persea americana) was immobilized on electrochemical1y synthesized polypyrrole (PPY) films using glutaraldehyde (GA) as a crosslinking agent. PPY and PPY/PPO-GA films were electrochemical1y characterized, mainly by cyclic voltametry, where electroactivity and electrochemical reversibility were evaluated. The detection of phenolic compounds in standard samples was made by chronoamperometry with a control over the compound concentration. The process of mass transfer was monitored with an electrochemical quartz crystal microbalance (EQCM). Our results indicated a good repeatability of the measurements for the detection of phenolic compounds. The stability of biosensor in a buffer solution has remained for 27 days, a result acceptable since it is found in the literature a time of life stable for similar systems around 30 days

Neste trabalho, foram fabricados biossensores amperométricos a partir do uso da polifenol oxidase (PFO), obtida do abacate como fonte enzimática, imobilizada em filmes de polipirrol (PPI) e que foram eletrossintetizados em meio de três diferentes eletrólitos de suporte (NaCl e NaClO4 e NaDDS). O método de imobilização enzimática foi o da adsorção, sendo a solução de enzima adicionada à solução com o pirrol e o eletrólito durante o processo de eletropolimerização. Os filmes de PPI/PFO foram caracterizados por técnicas eletroquímicas, principalmente por voltametria cíclica. A detecção de compostos fenólicos (catecol e pirogalol) foi realizada pela técnica de cronoamperometria após se variar a concentração do analito. A morfologia dos filmes foi estudada por microscopia de força atômica (AFM), sendo observado que a presença da enzima no filme polimérico assim como o uso de diferentes eletrólitos de suporte levou a diferenças na superfície dos filmes. Além disto, verificou-se que o biossensor construído a partir do uso do NaCl, apresentava uma resposta mais eficiente, ou seja, ele foi capaz de detectar catecol e pirogalol em um menor limite de detecção. / In this study amperometric biosensors were manufactured from the use of polyphenol oxidase (PPO) obtained from avocado as a source of enzyme immobilized in polypyrrole (PPY) films that were electrosynthesized with three different support electrolytes (NaCl, NaClO4 and NaDDS). The method of enzyme immobilization was the adsorption. The PPO was added in the solution containing pyrrole and electrolyte during electropolymerization. The PPY/PPO films were characterized by electrochemical techniques mainly by cyclic voltammetry. Detection of phenolic compounds (catechol and pyrogallol) was performed by the technique of chronoamperometry after varying the concentration of the analyte. The morphology of the films was studied by the atomic force microscopy (AFM) and observed that the presence of the enzyme in the polymer film and the use of different electrolytes support led to differences in the surface of films. However it was found that the biosensor constructed from the use of NaCl showed more efficient response and it was able to detect catechol and pyrogallol in a lower limit of detection.

Protein-protein interactions build large networks which are essential in understanding complex diseases. Due to limitations of experimental methodology there are problems with large amounts of false negative and positive interactions; and a large gap in the amount of known interactions and structurally determined interactions. By using computational methods these problems can be alleviated. In this thesis the quality of a newly developed pipeline (InterPred) were investigated for its ability to generate coarse interaction models and score them. This ability was investigated by performing docking experiments in Rosetta on models generated in InterPred. The results suggest that InterPred is highly successful in generating good starting points for docking proteins in silico and to distinguish the quality of models.

No description available.

Due to the high dimensionality of most biological data, it is a difficult task to directly analyze, model and visualize the data to gain biological insight. Thus, dimensionality reduction becomes an imperative pre-processing step in analyzing and visualizing high-dimensional biological data. Two major approaches to dimensionality reduction in genomic analysis and biomarker identification studies are: Feature extraction, creating new features by combining existing ones based on a mapping technique; and feature selection, choosing an optimal subset of all features based on an objective function. In this dissertation, we show how our innovative reduction schemes effectively reduce the dimensionality of DNA gene expression data to extract biologically interpretable and relevant features which result in enhancing the biomarker identification process. To construct biologically interpretable features and facilitate Muscular Dystrophy (MD) subtypes classification, we extract molecular features from MD microarray data by constructing sub-networks using a novel integrative scheme which utilizes protein-protein interaction (PPI) network, functional gene sets information and mRNA profiling data. The workflow includes three major steps: First, by combining PPI network structure and gene-gene co-expression relationship into a new distance metric, we apply affinity propagation clustering (APC) to build gene sub-networks; secondly, we further incorporate functional gene sets knowledge to complement the physical interaction information; finally, based on the constructed sub-network and gene set features, we apply multi-class support vector machine (MSVM) for MD sub-type classification and highlight the biomarkers contributing to the sub-type prediction. The experimental results show that our scheme could construct sub-networks that are more relevant to MD than those constructed by the conventional approach. Furthermore, our integrative strategy substantially improved the prediction accuracy, especially for those ‘hard-to-classify' sub-types. Conventionally, pathway-based analysis assumes that genes in a pathway equally contribute to a biological function, thus assigning uniform weight to genes. However, this assumption has been proven incorrect and applying uniform weight in the pathway analysis may not be an adequate approach for tasks like molecular classification of diseases, as genes in a functional group may have different differential power. Hence, we propose to use different weights for the pathway analysis which resulted in the development of four weighting schemes. We applied them in two existing pathway analysis methods using both real and simulated gene expression data for pathways. Weighting changes pathway scoring and brings up some new significant pathways, leading to the detection of disease-related genes that are missed under uniform weight. To help us understand our MD expression data better and derive scientific insight from it, we have explored a suite of visualization tools. Particularly, for selected top performing MD sub-networks, we displayed the network view using Cytoscape; functional annotations using IPA and DAVID functional analysis tools; expression pattern using heat-map and parallel coordinates plot; and MD associated pathways using KEGG pathway diagrams. We also performed weighted MD pathway analysis, and identified overlapping sub-networks across different weight schemes and different MD subtypes using Venn Diagrams, which resulted in the identification of a new sub-network significantly associated with MD. All those graphically displayed data and information helped us understand our MD data and the MD subtypes better, resulting in the identification of several potentially MD associated biomarker pathways and genes. / Ph. D.