Made available in DSpace on 2014-10-09T12:35:12Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:12Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A tomografia por emissão de pósitrons associada à tomografia computadorizada (PET/CT) é um dispositivo que combina as características de medicina nuclear (PET) e de radiologia (CT) obtendo imagens metabólicas (PET) e anatômicas sobrepostas (CT). Combinando as duas tecnologias de exames, o exame PET / CT permite aos médicos diagnosticar com maior precisão e identificar o câncer, doenças cardíacas e distúrbios cerebrais. O radiofármaco 18FFAc (fluoroacetato) é promissor para a detecção de tumores primários de próstata e de mama, utilizando a técnica de PET/CT. Estudos recentes mostram a eficácia do 18F-FAc na detecção de tumores que têm baixa captação de 18F-FDG (fluordesoxiglicose). O fluoroacetato é um substrato para a acetil-CoA sintase, enzima que metaboliza ácido fluorocitrato que não é mais metabolizado, levando à inibição da aconitase e do ácido tricarboxílico. O objetivo deste trabalho foi desenvolver um radiofármaco emissor de pósitron, 18F-FAc no IPEN-CNEN/SP em um acordo com o Hospital AC-Camargo / São Paulo. O íon fluoreto (18F-) foi produzido, usando os cíclotrons Cyclone 30 e 18 da IBA localizados no IPEN-CNEN/SP, através da irradiação de água enriquecida em 18O com prótons e dose integrada de 30μAh. A marcação do 18F-FAc foi realizada em um módulo de síntese TRACERlab MXFDG (GE), utilizando kits adquiridos da ABX. O controle de qualidade radioquímico de 18F-FAc foi realizado por cromatografia em camada fina TLC-SG 25 folhas de alumínio em tiras (1,5 x 12 cm ) usando como solvente clorofórmio:metanol (1:1). Para o controle de qualidade radionuclídico, amostras de 18F-FAc e 18F-Fluoreto foram analisadas por espectroscopia de raios-gama. A avaliação dos solventes residuais foi realizada por cromatografia em fase gasosa e a análise de kryptofix foi realizada por TLC utilizando tiras de TLC-SG, metanol:clorofórmio (9:1) como solvente e padrões de kryptofix 2.2.2. Os estudos de biodistribuição foram realizados com 18FFAc injetado em camundongos swiss sadios. Um procedimento reprodutível foi desenvolvido para o preparo do 18F-FAc com um rendimento de marcação de 37% (não corrigido) e 52% (corrigido para o decaimento) e estabilidade de 19 horas. A análise de controle de qualidade mostrou que o produto tinha as exigências adequadas para utilização, com pureza radioquímica superior a 99,9%. Os estudos de biodistribuição em animais sadios mostraram a esperada captação em todos os órgãos medidos com eliminação renal e intestinal. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP / FAPESP:11/03138-8

Made available in DSpace on 2014-10-09T12:53:14Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:05Z (GMT). No. of bitstreams: 0 / A pesquisa teve como objetivo a utilização da radiação gama do Cobalto-60 como tratamento quarentenário de plantas medicinais, aromáticas e condimentares desidratadas infestadas por Lasioderma serricorne e Plodia interpunctella determinando as doses desinfestantes atendendo o critério de não emergência de adultos das espécies em estudo e analisando através da Cromatografia de Camada Delgada os efeitos da radiação gama do Cobalto-60 sobre o princípio ativo dos substratos desidratados de Chamomilla recutita, Pimpinella anisum, Origanum vulgare, Cymbopogon citratus, Ocimum basilicum e Thymus vulgaris. O trabalho foi desenvolvido no Laboratório de Inseticidas do Instituto Biológico em São Paulo no período de agosto de 2005 a junho de 2007. A fonte de radiação gama utilizada foi um irradiador experimental de Cobalto-60, modelo Gamacell 220, localizado no Instituto de Pesquisas Energéticas e Nucleares ? IPEN, localizado em São Paulo. No período de 30 dias após a irradiação das amostras avaliou-se o número de adultos emergidos de Lasioderma serricorne e Plodia interpunctella, utilizando os dados de mortalidade para a análise de Probit. Obteve-se 100% de não emergência de adultos de Lasioderma serricorne com a dose de 2,00 kGy e 100% de não emergência de adultos de Plodia interpunctella com a dose de 2,25 kGy. A Análise Cromatográfica de Camada Delgada efetuada não revelou diferença na composição química dos substratos analisados. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Dans cette thèse, les mécanismes de rayures en contact glissant sur des empilements de couches minces de faible adhésion ont été étudiés grâce à un tribomètre bille/plan à vision in-situ. Dans le cadre de ce travail, des expériences ont été menées sur un empilement modèle : verre/ZnO/Ag/ZnO/Si3N4 et l'impact de plusieurs paramètres a été étudié : force, taille de la bille, épaisseur de la surcouche, adhésion et coefficient de frottement.Nous avons montré que la rayure se déroule en trois phases successives : initiation, développement et régime stationnaire. L'initiation débute par une fissuration transverse de l’empilement suivi par un délaminage due à la bifurcation de la fissure à l’interface au-dessus de l’argent. Seule la taille caractéristique de ces phénomènes dépend de paramètres comme l'épaisseur des couches ou l'adhésion. Après l'initiation, un phénomène de plissage en milieu confiné se produit et permet de débuter la construction d'un tas de débris à l’avant du frotteur par accumulation. Finalement, en régime stationnaire, on constate que la rayure est uniquement pilotée par l’interaction entre le tas de débris et la couche. On a montré que la complexité de cette interaction rend toute mesure d’adhésion à partir des caractéristiques post-mortem de la rayure quasi-impossible.Finalement, il a été montré qu'il est possible d'améliorer la résistance à la rayure d’un empilement en texturant à l'échelle nanométrique sa couche d'argent. L’origine de cette amélioration vient d’une augmentation de l'adhésion par un effet de piégeage qui a été étudié à l'aide d'expériences de clivage. / In this PhD thesis, the scratch mechanisms during sliding contact on thin layers with low adhesion have been investigated with a ball on plane tribometer that allows in-situ microscopic observations. In this work, experiments were carried out on glass/ZnO/Ag/ZnO/Si3N4 model stacks and the impact of several parameters was studied: force, size of the ball, thickness of the overcoat, adhesion and friction coefficient.We have shown that the scratch process has three successive phases: initiation, development and steady state. Initiation begins with transverse cracks in the stack followed by delamination due to crack bifurcation at the interface above the silver layer. Only the characteristic size of these phenomena depends on parameters such as the thickness of the layer or its adhesion. After initiation, a phenomenon of pleating occurs even if confined under the contact and leads to the building of a pile of debris at the front of the contact zone by accumulation. Finally, in steady state, the scratch is only driven by the interaction between the pile of debris and the layers. It has been shown that the complexity of this interaction makes quasi-impossible any measure of adhesion based on the post mortem characteristics of the scratch.Finally, it has been shown that it is possible to improve the scratch resistance of a stack by patterning its silver layer at nanoscale. The origin of this improvement derives from an increase of adhesion due to pinning effect which has been demonstrated by using cleavage experiments.

Aujourd’hui, le principal facteur limitant le photovoltaïque est le prix élevé du kWh produit par les modules PV. Pour faire face à cette difficulté, les recherches actuelles se concentrent autour de plusieurs leviers et solutions alternatives : la réduction du coût énergétique avec notamment la réduction du coût de la matière première, qui consiste en la diminution de l’épaisseur des wafers de silicium, ou encore l’élaboration de cellules en couches minces de silicium. Ce dernier procédé a pour but de s’affranchir de l’étape de sciage des blocs de silicium, nécessaire pour la réalisation de plaquette photovoltaïque de faible épaisseur. C’est cette dernière approche qui nous a conduits à proposer un procédé d’élaboration de couches minces à l’aide d’un plasma et du chauffage du substrat. Par ailleurs, quel que soit le procédé choisi pour atteindre la cristallinité et la pureté exigées pour le grade solaire, il est nécessaire de disposer de technique analytique multiélémentaire pour contrôler l’évolution de la pureté en fonction des paramètres. La LIBS que nous avons développée au laboratoire offre l’opportunité de répondre à ces attentes : très basses limites de détection tout en permettant un suivi en ligne du silicium à l’état solide ou en fusion. / Today, the main limiting factor of PV is the high price of electricity production by the PV modules. To cope with this difficulty, current researches focus on several ways and alternatives solutions: reducing energy costs including reducing the cost of the raw material, which consists in reducing the thickness of silicon wafers or in the development of cells in thin silicon layers. The latter process is intended to overcome the sawing step of silicon ingots which is necessary for the realization of photovoltaic wafer. It is this very approach that led us to develop a method to prepare thin films by using plasma and heating the substrate. Moreover, whatever the method chosen to achieve the required crystallinity and purity for solar grade, it is necessary to have a multi-elements analytical technique to control the evolution of purity. In our laboratory, we have developed LIBS which can meet these expectations, i-e very low detection limits while allowing online tracking of silicon in solid or liquid state.

This diploma thesis deals with changing properties of the thin layered titanium dioxide dispersion depending on the time of ball-milling. Titanium dioxide is immobilized on glass or conductive glass using the spin-coating method and the prepared thin layers are then characterized by various analytical methods. All of used analytical methods are described in theoretical and experimental sections, these methods include scanning electron microscopy, profilometry, dynamic light scattering, integrating sphere, ellipsometry, BET isotherm, voltammetry and chronoamperometry. At the summary of this diploma thesis is described how the properties of titanium dioxide thin layers change during ball-milling process.

Keywords: ambient ionization techniques; mass spectrometry; desorption electrospray ionization; desorption atmospheric pressure photoionization; thin layer chromatography; lipids, mass spectrometry imaging Ambient ionization technique in mass spectrometry is an ionization, which carries out in open space outside the machine and which does not require any, or only a minimal sample pretreatment. DESI (desorption electrospray ionization) and DAPPI (desorption atmospheric pressure photoionization) equipped with software control of the spray emitter position for analysis of low molecular organic compounds were investigated in this thesis. These methods use a spray of solvents for desorption and ionization molecules from solid substrate. Conditions for the successful analysis of phospholipids, wax esters and some other compounds were developed. Ambient ionization techniques were quantitatively compared. The application was HPTLC/DESI-MS of lipid's mixture and HPTLC/DAPPI-MS of vernix caseosa. DAPPI-MS was applied for the analysis of termites of Prorhinotermes genus (Isoptera, Rhinotermitidae). Pilot experiments of two dimensional analysis and mass spectrometry imaging were realized.

ectroscopic reflectometry is measurement technique that enables the study of the thickness and refractive index of thin layers. This thesis deals with its use for the study of lubrication films within EHD contact and verifies a new approach suggested in recent publications. It is focused on the development of an optical arrangement and mathematical model for the lubrication film thickness measurement within the entire EHD contact. This technique brings the possibility to study the pressure distribution within the contact area through the evaluation of changes in lubricant refractive index.

Please read the abstract in the section 00front of this document. / Dissertation (MSc (Pharmacology))--University of Pretoria, 2003. / Pharmacology / unrestricted

A process, called carbon nanotube templated microfabrication (CNT-M) makes high aspect ratio microstructures out of a wide variety of materials by growing patterned vertically aligned carbon nanotubes (VACNTs) as a framework and then infiltrating various materials into the frameworks by chemical vapor deposition (CVD). By using the CNT-M procedure, a partial Si infiltration of carbon nanotube frameworks results in porous three dimensional microscale shapes consisting of silicon-carbon nanotube composites. The addition of thin silicon shells to the vertically aligned CNTs (VACNTs) enables the fabrication of robust silicon nanostructures with edibility to design a wide range of geometries. Nanoscale dimensions are determined by the diameter and spacing of the resulting silicon/carbon nanotubes while microscale dimensions are controlled by the lithographic patterning of CNT growth catalyst. The characterization and application of the new silicon nanomaterial, silicon-carbon core-shell nanotube (Si/CNT) composite, is investigated thoroughly in the dissertation.The Si/CNT composite is used as thin layer chromatography (TLC) separations media with precise microscale channels for fluid flow control and nanoscale porosity for high analyte capacity. Chemical separations done on the CNT-M structured media outperform commercial high performance TLC media resulting from separation efficiency and retention factor. The Si/CNT composite is also used as an anode material for lithium ion batteries. The composite is assembled into cells and tested by cycling against a lithium counter electrode. This CNT-M structured composite provides an effective test bed for studying the effects of geometry (e.g. electrode thickness, porosity, and surface area) on capacity and cycling performance. A combination of high gravimetric, volumetric, and areal capacity makes the composite an enabling materials system for high performance Li-ion batteries.Last, a thermal annealing to the Si/CNT composite results in the formation of silicon carbide nanowires (SiCNWs). This combination of annealing and Si/CNTs yields a unique fabrication approach resulting in porous three dimensional silicon carbide structures with precise control over shape and porosity.

No description available.