Thin films and coatings of oxides are used in various fields of science and technology, such as semiconductor and optoelectronic devices, gas sensors, protective and wear resistant coatings etc. Of late, there has been a tremendous interest in pure and doped vanadium dioxide as thermoelectric switch material. VO2 has been doped with hetero-atoms such as W, Mo, Nb, Ti etc. and effects of doping have been correlated with feasibility of being used as a smart window material. The oxide Al2O3 has been studied as an alternative gate dielectric. Ga2O3 is also a contender for replacing SiO2 as a dielectric material. Atomic layer deposition (ALD) is a technique for the deposition of thin films of various materials and is found to be of considerable scientific and technological importance. In particular, using β-diketonate complexes as precursors is very useful in preparing thin films of oxides, as these precursors already contain a metal-oxygen bond. In this thesis, β-diketonate complexes have been used as precursors for deposition of thin films. The thesis has been divided into two parts: First part deals with deposition and characterization of thin films of VO2 on glass and fused quartz. The second part deals with synthesis and chemical and thermal characterization of bimetallic Al-Ga acetylacetonates along with thin film deposition using the same. Chapter 1 presents a brief introduction to application of thin films of oxides in various fields of science and technology. A brief introduction to the ALD reactor used for the current work is also presented. The importance of thermal analysis of precursors for CVD is briefly reviewed. Chapter 2 deals with the instruments and methods used for the work done for this thesis. In Chapters 3 and 4 of the thesis, a detailed study of deposition of VO2 films on glass and fused quartz has been presented. The films deposited have been analyzed using a host of techniques, for their texture, microstructure and electrical properties. In spite of chemical similarities, considerable differences in structure and properties have been observed between the films deposited on the two substrates. These differences have been explained on the basis of the small chemical differences between the two substrates. Chapters 5, 6 and 7 deal with synthesis, thermal characterization and use of bimetallic Al-Ga precursors, respectively. The bimetallic acetylacetonates have been synthesized using ‘homogenization in solution’ approach. Chemical characterization of the precursors revealed that nominal percentages of Al and Ga are retained in the solid precursors. Single crystal structure confirmed the observation. Thermal analysis of the precursors showed that the precursors, which are solid solutions of Al and Ga acetylacetonates, show negative deviation from the Raoult’s Law. Films were deposited using these precursors and were found to near completely retain the composition of the precursors. Chapter 8 of the thesis presents the conclusions of the current work and proposes future directions.

The thesis presented here is focused on the synthesis of iron-bismuth alkoxides and siloxides as precursors for multiferroic BiFeO₃ systems. Spectrum of novel cyclopentadienyl substituted iron-bismuth complexes of the general type [{Cp^y(CO)₂Fe}BiX₂], as potential precursors for cyclopentadienyl iron-bismuth alkoxides or siloxides [{Cp^y(CO)₂Fe}Bi(OR)₂] (R-O^tBu, OSiMe₂^tBu), were obtained and characterised. The use of wide range of cyclopentadienyl rings in the iron carbonyl compounds allowed for a comprehensive analysis of its influence on structure, reactivity as well as solubility of the studied complexes, which are crucial features of potential precursors. The results fill the gap in the chemistry of cyclopentadienyl iron-bismuth complexes. In this work a new method of preparation of novel alkoxides or siloxides iron-bismuth complexes has been developed. In the reaction of Fe₂(CO)₉ with Bi(O^tBu)₃ or Bi(OSiMe₂^tBu)₃ molecular precursors for preparation of heterobimetallic oxides were obtained. Moreover, characterised compounds allowed to extend the knowledge about existence of iron-bismuth clusters and open new ways for the further investigations on the carbonyl iron-bismuth siloxides and alkoxides. The resulting compounds are good single source precursors for the BiFeO₃ materials. The presented synthetic route can be generalized and other heterobimetallic compounds can be obtained. This work should also be helpful in the designing new precursors for synthesis of metal oxides.

Résumé La Ribonucléase P (RNase P) est une enzyme principalement reconnue pour sa participation à la maturation en 5’des ARN de transfert (ARNt). Cependant, d’autres substrats sont reconnus par l’enzyme. En général, la RNase P est composée d’une sous-unité ARN (le P-ARN, codé par le gène rnpB) qui porte le centre actif de l’enzyme et d’une ou de plusieurs sous-unités protéiques (la P-protéine). Les P-ARN chez toutes les bactéries, la majorité des archéobactéries et dans le génome nucléaire de la plupart des eucaryotes, possèdent généralement une structure secondaire très conservée qui inclut le noyau (P1-P4); l’hélice P4 constitue le site catalytique de l’enzyme et l’hélice P1 apparie les extrémités du P-ARN en stabilisant sa structure globale. Les P-ARN mitochondriaux sont souvent moins conservés et difficiles à découvrir. Dans certains cas, les seules régions de structure primaire qui restent conservées sont celles qui définissent le P4 et le P1. Pour la détection des gènes rnpB, un outil de recherche bioinformatique, basé sur la séquence et le profil de structure secondaire, a été développé dans le laboratoire. Cet outil permet le dépistage de toutes les séquences eucaryotes (nucléaires et mitochondriales) du gène avec une très grande confiance (basée sur une valeur statistique, E-value). Chez les champignons, plusieurs ascomycètes encodent un gène rnpB dans leur génome mitochondrial y compris tous les membres du genre d’Aspergillus. Cependant, chez les espèces voisines, Neurospora crassa, Podospora anserina et Sordaria macrospora, une version mitochondriale de ce gène n’existe pas. Au lieu de cela, elles contiennent deux copies nucléaires du gène, légèrement différentes en taille et en contenu nucléotidique. Mon projet a été établi dans le but d’éclaircir l’évolution de la RNase P mitochondriale (mtRNase P) chez ces trois espèces voisines d’Aspergillus. En ce qui concerne les résultats, des modèles de structures secondaires pour les transcrits de ces gènes ont été construits en se basant sur la structure consensus universelle de la sous-unité ARN de la RNase P. Pour les trois espèces, par la comparaison de ces modèles, nous avons établi que les deux copies nucléaires du gène rnpB sont assez distinctes en séquence et en structure pour pouvoir y penser à une spécialisation de fonction de la RNase P. Chez N. crassa, les deux P-ARN sont modifiés probablement par une coiffe et les extrémités 5’, 3’ sont conformes à nos modèles, ayant un P1 allongé. Encore chez N. crassa, nous avons constaté que les deux copies sont transcrites au même niveau dans le cytoplasme et que la plus petite et la plus stable d’entre elles (Nc1) se retrouve dans l’extrait matriciel mitochondrial. Lors du suivi du P-ARN dans diverses sous-fractions provenant de la matrice mitochondriale soluble, Nc1 est associée avec l’activité de la RNase P. La caractérisation du complexe protéique, isolé à partir de la fraction active sur un gel non dénaturant, révèle qu’il contient au moins 87 protéines, 73 d’entre elles ayant déjà une localisation mitochondriale connue. Comme chez la levure, les protéines de ce complexe sont impliquées dans plusieurs fonctions cellulaires comme le processing de l’ADN/ARN, le métabolisme, dans la traduction et d’autres (par exemple : la protéolyse et le repliement des protéines, ainsi que la maintenance du génome mitochondrial). Pour trois protéines, leur fonction est non déterminée. / Abstract Ribonuclease P (RNase P) is an endonuclease that cleaves 5’- leader sequences from tRNA precursors and a few other small RNAs. In most cases, the enzyme is a ribonucleo-protein complex (ribozyme), containing an RNA subunit (P-RNA; encoded by the rnpB gene) that carries the active centre of the enzyme, plus one or more protein subunits. P-RNAs in Bacteria, Eukarya and Archaea have a highly conserved secondary structure including the core P1 and P4 helices. P4 forms the catalytic site of the ribozyme, and P1 pairs the RNA termini, stabilizing overall structure and protecting from nuclease degradation. For processing of mitochondrial (mt) tRNAs, certain eukaryotic species (e.g., Saccharomyces cerevisiae, Aspergillus nidulans) have separate mtDNA-encoded P-RNAs (of bacterial origin). Mt P-RNAs are often less conserved, and difficult to discover. To identify rnpB genes, we have developed a search tool based on sequence plus secondary structure profiles. It predicts all known eukaryotic (nuclear and organellar) rnpB genes with high confidence (based on E-values). In fungi, many ascomycetes encode a mitochondrial rnpB gene, including all members of Aspergillus. Yet, the closely related Neurospora crassa, Podospora anserina and Sordaria macrospora lack an mtDNA-encoded gene version. Instead, they contain two nuclear gene copies with slightly different sequences. My project aims to elucidate the evolution of mitochondrial RNase P in these three closely related species. We have established secondary structure models based on comparisons with the universal minimum consensus secondary structure for all nuclear gene mtP-RNAs copies in all three species. By comparison of these secondary structure models, we have established that the two nuclear copies of rnpB gene are quite distinct in sequence and structure, suggesting a specialization of function. In N. crassa, both P-RNAs are modified most likely by capping, and 5’- 3’ termini perfectly conform to P-RNA structure models that have an elongated P1 helical pairing. Furthermore, we find that the two nuclear copies of rnpB gene are present at about the same level in the cytoplasm, and that the shorter form of P-RNA (Nc1) translocates into the (soluble) mitochondrial matrix. When tracing P-RNA in different mitochondrial sub-fractions of a native gel, the presence of Nc1 and mitochondrial RNase P activity are associated. A proteomics characterization of a P-RNA complex isolated by native gel electrophoresis reveals that it contains at least 87 proteins, 73 of which are of known mitochondrial localization. Like in yeast, the complex contains proteins potentially involved in other DNA/RNA processing activities, but also in translation, in metabolism, and in protein folding. Only three proteins are of unknown function.

Diss. (sammanfattning) Umeå : Univ., 2008. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Missouri--Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves: 215-225). Also available on the Internet.

Thesis (Ph.D.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 87 pages. Includes Vita. Includes bibliographical references.

Made available in DSpace on 2014-12-17T14:07:09Z (GMT). No. of bitstreams: 1 Maria JSL_DISSERT.pdf: 2126864 bytes, checksum: 5f05e8062e1e0a0ae6a41666703f3c86 (MD5) Previous issue date: 2013-06-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The research and development of nanostructured materials have been growing significantly in the last years. These materials have properties that were significantly modified as compared to conventional materials due to the extremely small dimensions of the crystallites. The tantalum carbide (TaC) is an extremely hard material that has high hardness, high melting point, high chemical stability, good resistance to chemical attack and thermal shock and excellent resistance to oxidation and corrosion. The Compounds of Tantalum impregnated with copper also have excellent dielectric and magnetic properties. Therefore, this study aimed to obtain TaC and mixed tantalum oxide and nanostructured copper from the precursor of tris (oxalate) hydrate ammonium oxitantalato, through gas-solid reaction and solid-solid respectively at low temperature (1000 ? C) and short reaction time. The materials obtained were characterized by X-ray diffraction (XRD), Rietveld refinement, Scanning Electron Microscopy (SEM), Spectroscopy X-Ray Fluorescence (XRF), infrared spectroscopy (IR), thermogravimetric (TG), thermal analysis (DTA) and BET. Through the XRD analyses and the Reitiveld refinement of the TaC with S = 1.1584, we observed the formation of pure tantalum carbide and cubic structure with average crystallite size on the order of 12.5 nanometers. From the synthesis made of mixed oxide of tantalum and copper were formed two distinct phases: CuTa10O26 and Ta2O5, although the latter has been formed in lesser amounts / A pesquisa e o desenvolvimento de materiais nanoestruturados v?m crescendo significativamente nos ?ltimos anos. Estes materiais apresentam propriedades significativamente modificadas em compara??o ?s dos materiais convencionais, devido ?s dimens?es extremamente reduzidas dos cristalitos. O carbeto de t?ntalo (TaC) ? um material extremamente duro, apresentando elevada dureza, elevado ponto de fus?o, elevada estabilidade qu?mica, boa resist?ncia ao ataque qu?mico e choque t?rmico e excelente resist?ncia ? oxida??o e corros?o. Os compostos de T?ntalo impregnados com Cobre tamb?m possuem excelentes propriedades diel?tricas e magn?ticas. Desta forma este trabalho teve como objetivo a obten??o de TaC e do ?xido misto de t?ntalo e cobre nanoestruturado a partir do precursor tris(oxalato)oxitantalato de am?nio hidratado, atrav?s de rea??o g?s-s?lido e s?lido-s?lido, respectivamente,a baixa temperatura (1000?C) e curto tempo de rea??o. Os materiais obtidos foram caracterizados atrav?s de Difra??o de Raios-X (DRX), Refinamento Rietveld, Microscopia Eletr?nica de Varredura (MEV), Espectroscopia por Fluoresc?ncia de Raios-X (FRX), Espectroscopia de Infravermelho (IV), Termogravim?trica (TG), Analise Termodiferencial (DTA) e BET. Atrav?s das analises de DRX e do refinamento Reitiveld para o TaC com S= 1,1584 observou-se a forma??o do carbeto de t?ntalo puro com estrutura c?bica e tamanho m?dio de cristalitos na ordem de 12,5 nan?metros. Para a s?ntese realizada do ?xido misto de t?ntalo e cobre houve a forma??o de duas fases distintas: CuTa10O26 e Ta2O5, embora esta ?ltima tenha sido formada em menor quantidade

Many children diagnosed with autism spectrum disorder (ASD) engage in problem behaviors (e.g., aggression and self-injurious behavior) that present safety concerns for both the children themselves and others around them. Previous research has shown that treating precursor behaviors that precede problem behavior may prove to be an alternative, safer method for preventing and treating problem behavior. The present study used a multiple baseline design across subjects (n = 4) to assess the efficacy of relaxation interventions on reducing precursor behavior and preventing problem behavior in children with ASD. Researchers first identified precursor behaviors for all participants through observation. During the intervention phase, all four children were taught deep breathing relaxation exercises. After participants received relaxation training, researchers cued relaxation exercises when precursors occurred, and the frequency of precursor, problem, and on-task behavior was observed. Results showed that problem behavior decreased in all participants following the relaxation intervention. Additionally, for the majority of participants, precursor behavior decreased and on-task behavior increased post-intervention. Implications for practice and future research on interventions that target precursor behaviors are discussed.

Made available in DSpace on 2014-12-17T14:58:06Z (GMT). No. of bitstreams: 1 EverlaniaMS_DISSERT.pdf: 3651916 bytes, checksum: 47bd28b5197e92c8cda3dddf63274b6d (MD5) Previous issue date: 2011-02-08 / Considering the constant evolution of technology in growth and the need for production techniques in the ceramics area to move forward together, we sought in this study, the research and development of polymeric precursor method to obtain inorganic ceramic pigments. Method that provides quality to obtain the precursor powders of oxides and pigments at the same time, offers time and cost advantages, such as reproducibility, purity and low temperature heat treatment, control of stoichiometry. This work used chromium nitrate and iron nitrate as precursors. The synthesis is based on the dissolution of citric acid as a complexing agent, addition of metal oxides, such as ion chromophores; polymerization with ethylene glycol and doping with titanium oxide. Passing through precalcination, breakdown, thermal treatments at different temperatures of calcination (700 to 1100 oC), resulting in pigments: green for chromium oxide deposited on TiO2 (CrTiO3) and orange for iron oxide deposited on TiO2 ( FeTiO3). Noticing an increase of opacity with increasing temperature. Were performed thermal analysis (TG and ATD) in order to evaluate its thermodecomposition. The powders were also characterized by techniques such as XRD, revealing the formation of crystalline phases such as iron titanate (FeTiO3) and chrome titanate (CrTiO3), SEM, demonstrating formation of rounded particles for both oxides and Spectroscopy in the UV-Visible Region, verifying the potential variation and chromaticity os pigments. Thus, the synthesized oxides were within the requirements to be applied as pigments and shown to be possible to propose its use in ceramic materials / Considerando a evolu??o tecnol?gica em constante crescimento e a necessidade de t?cnicas de produ??o na ?rea de cer?mica que avancem em conjunto, buscou-se neste estudo, a pesquisa e desenvolvimento do m?todo dos precursores polim?ricos para obten??o de pigmentos cer?micos inorg?nicos. M?todo que proporciona qualidade a obten??o dos p?s precursores dos ?xidos pigmentantes e ao mesmo tempo, oferece vantagens de tempo e custo, como: reprodutibilidade, pureza, baixas temperaturas de tratamento t?rmico e controle de estequiometria. Neste trabalho foram utilizados nitrato de cromo e nitrato de ferro, como precursores. A s?ntese foi baseada na dissolu??o do ?cido c?trico, como agente complexante; adi??o dos ?xidos met?licos, como ?ons crom?foros; polimeriza??o com etileno glicol e dopagem com ?xido de tit?nio. Passando por pr?-calcina??o, desagrega??o, tratamentos t?rmicos em diferentes temperaturas de calcina??o (700 a 1100 oC), resultando em pigmentos: verde para o ?oxido de cromo depositado sobre TiO2 (CrTiO3) e laranja para o ? Oxido de Ferro depositado sobre TiO2 (FeTiO3). Percebendo-se aumento de sua opacidade com o aumento da temperatura. Foram feitas an?lises t?rmicas (TG e ATD), a fim de avaliar sua termo de composi??o. Os p?s foram caracterizados tamb?m por t?cnicas como DRX, revelando-se a forma??o de fases cristalinas como Titanato de Ferro (FeTiO3) e Titanato de Cromo (CrTiO3); MEV, evidenciando-se forma??o de aglomerados de part?culas ligeiramente hexagonais para ambos os ?oxidos e Espectroscopia na Regi?o do UV-Vis?vel, verificando a varia??o e o potencial de cromaticidade dos pigmentos. Desta forma, os ?xidos sintetizados apresentaram-se dentro dos requisitos necess?rios para serem aplicados como pigmentos e mostra-se poss?vel propor sua utiliza??o em materiais cer?micos

Fundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SE / Aedes aegypti is the main vector of the dengue virus, urban yellow fever and emerging arboviruses in Brazil as zika and chikungunya. The use of chemical pesticides is still the main control mechanism vector, their overuse has led to the emergence of resistant insects besides mammalian toxicity and the environment. Essential oils such as essential oil Sizygum aromaticum (OESA) is an alternative in control of Ae. aegypti.In this context , the aim of this study was to develop and characterize nanostructured systems from the use of PPG -5 CETETH -20 ( cetyl alcohol propoxylated 5 OP ethoxylate 20 EO) , water, sodium alginate and essential oil Sizygum aromaticum ( OESA ) with potential application in larvicide control of Ae. aegypti. The systems were obtained by phase diagram composed of water, oleic acid, PPG-5 CETETH-20 (OA)in the ratio 2: 1 and OESA, and characterized by techniques polarized light microscopy (MLP), Smallangle Xray scattering(SAXS) and rheological analysis.In this diagram, we chose a liquid crystalline phase precursor to polymer incorporation of sodium alginate, to increase the physical stability of the system. Were also made in water increases precursor and then characterized by such techniques. The larvicidal activity was evaluated from the determination of the median lethal concentration (LC50) against Ae. aegypti. According to the results the main constituent of OESA was eugenol (76.75 %), oil yield was 3.66% (w / v) and density of 1,04g / ml. We observed four distinct regions of the diagram, liquid crystal (LC) emulsion (ME), microemulsion (ME) and phase separation. Through the images of MLP was observed isotropic systems as (MEs) and anisotropic systems as lamellar CLs.The SAXS measurements confirmed the structures visualized by MLP, showing broad peaks of low intensity for MEs, phase transition and the ratio between CL lamellar peaks of 1: 2: 3. The study showed that the rheological properties of the systems and MEs phase transition are Newtonians and LCs are non-Newtonian. With the aqueous phase the increased phase precursor showed a greater degree of structuring, becoming lamellar liquid crystalline systems. Confirmed through the MLP techniques to display "Maltese crosses '' SAXS with ratios of 1: 2: 3 and rheological analysis with an increase in storage modulus. After incorporating polymer, systems are presented anisotropic with lamellar system characteristics and hexagonal system having more than one set of lamellae observed in the MLP and confirmed by SAXS measurements, which showed ratios of 1: 2: 3 to lamellar CL and 1: 1.73: 2: 2.64 hexagonal CL. In rheological analysis showed an increase in independent storage modulus of the characteristic frequency of structured systems.For the larvicidal activity, A2 and F8 samples showed LC50 8.14 and 3.37 ppm, respectively, indicating the presence of the polymer contributed to a better larvicidal activity. Thereby, it can be concluded that there were obtained phase precusores with a potential use against Ae. aegypti larvae. / Aedes aegypti é o principal vetor dos vírus da dengue, febre amarela urbana e arboviroses emergentes no Brasil, como chikungunya e zika. O uso de inseticidas químicos ainda é o principal mecanismo de controle do vetor, seu uso indiscriminado tem provocado o surgimento de insetos resistentes além da toxicidade aos mamíferos e ao meio ambiente. Os óleos essenciais tais como o óleo essencial de Sizygum aromaticum (OESA) surge como alternativa no controle do Ae. aegypti. Neste contexto, o objetivo deste trabalho foi desenvolver e caracterizar sistemas nanoestruturados a partir da utilização de PPG-5 CETETH-20 (Álcool cetílico propoxilado 5 OP etoxilado 20 OE), água, alginato de sódio e óleo essencial de Sizygum aromaticum (OESA) com potencial aplicação no controle larvicida do Ae. aegypti. Primeiramente, foi feita a extração e a caracterização do OESA. Os sistemas foram obtidos através da construção do diagrama de fases composto por água, PPG-5 CETETH-20: ácido oléico (AO) na proporção 2:1 e OESA, e caracterizados através das técnicas de microscopia de luz polarizada (MLP), espalhamento de raios X a baixo ângulo (SAXS) e análise reológica. Neste diagrama optou-se por um precursor de fase líquido cristalina para incorporação do polímero alginato de sódio, a fim de aumentar a resistência do sistema ao intumescimento. Também foram feitos acréscimos de água no precursor e em seguida caracterizados pelas técnicas citadas. A atividade larvicida foi avaliada a partir da determinação da concentração letal média (CL50) contra as larvas do Ae. aegypti. De acordo com os resultados obtidos o principal constituinte do OESA foi o eugenol (76,75%), o rendimento do óleo foi de 3,66% (p /v) e densidade de 1,04 g/mL. Foram observadas quatro regiões distintas no diagrama, cristal líquido (CL), emulsão (EM), microemulsão (ME) e separação de fases. Através das imagens de MLP foi possível observar sistemas isotrópicos como MEs e sistemas anisotrópicos como CLs lamelares. As medidas de SAXS confirmaram as estruturas visualizadas por MLP, exibindo picos largos e de baixa intensidade para MEs, transição de fase e razão entre os picos de CL lamelar de 1: 2: 3. O estudo das propriedades reológicas demonstrou que os sistemas MEs e transição de fase são newtonianos e os CLs são não-newtonianos. Com o aumento de fase aquosa o precursor de fase apresentou um maior grau de estruturação, transformando-se em sistemas líquidos cristalinos lamelares. Confirmado através das técnicas de MLP com a visualização de “cruzes de malta‟‟, SAXS com razões de 1: 2: 3 e análise reológica apresentando um aumento no módulo de armazenamento. Após a incorporação do polímero, os sistemas apresentaram-se anisotrópicos com mistura de fases, possuindo características de sistema Lamelar e sistema hexagonal, observados na MLP e confirmados pelas medidas de SAXS, onde apresentaram razões de 1: 2: 3 e 1: 1,73: 2: 2,64 característicos de CL lamelares e hexagonais. Através da análise reológica foi possível observar um aumento no módulo de armazenamento independente da freqüência, característico de sistemas estruturados. Para a atividade larvicida, as amostras A2 e F8 demonstraram CL50 de 8,14 e 3,37 ppm, respectivamente, indicando que a presença do polímero contribuiu para uma maior atividade larvicida. Desse modo,pode-se concluir que foram obtidos precursores de fase com potencial uso contra as larvas de Ae. aegypti.