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.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-20T11:38:47Z No. of bitstreams: 2 Dissertação - Ariadne Canedo Eduardo - 2015.pdf: 1635500 bytes, checksum: 5c68f75920a8fc69b6de996110938818 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-20T11:40:09Z (GMT) No. of bitstreams: 2 Dissertação - Ariadne Canedo Eduardo - 2015.pdf: 1635500 bytes, checksum: 5c68f75920a8fc69b6de996110938818 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-10-20T11:40:09Z (GMT). No. of bitstreams: 2 Dissertação - Ariadne Canedo Eduardo - 2015.pdf: 1635500 bytes, checksum: 5c68f75920a8fc69b6de996110938818 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-02-26 / In recent years, research in the nanocomposites area of core-shell type increased significantly. The core-shell type nanoparticles with photoluminescence properties (PL) attract much attention from the scientific community. Are also of great interest nanoparticles that exhibit the upconversion energy, i.e. they absorbing low energy photons and emission high-energy photons. The present work has as objective nanocomposites synthesis of core-shell type, with CaTiO3 matrix (CT) and doped with rare earth ions Er3+ and Yb3+ in a variety composition and variations, to analysis the photoluminescent properties. The nanoparticles of the core and shell were obtained by the Method of Polymeric Precursors. The samples were characterized by X-ray diffraction (XRD) for structural characterization, and it was found that All samples presented the perovskite structure of the orthorhombic type. The characterization by Transmission Electron Microscopy (TEM) failed to demonstrate the formation of core-shell, requiring analysis by Energy Dispersive X-ray (EDX), which showed the presence of rare earth Er3+ and Yb3+ in the different layers. The UV-Vis gap allowed the calculation of the shell and core samples. The PL emission results were used to relate the thickness of the shell and the intensity of the emission. On the other hand, to study the upconversion energy, core materials showed a higher intensity than in the core-shell; the best intensity in the core-shell was found with doping the core with Yb3+ and Yb3+ with shell and Er3+ suggesting the transfer of energy between the layers. / Nos últimos anos, pesquisas na área de nanocompósitos do tipo core-shell cresceram significativamente. Atualmente nanopartículas do tipo core-shell com propriedades fotoluminescente (FL) atraem muita atenção da comunidade científica. Também são de grande interesse nanopartículas que apresentam a conversão ascendente de energia, ou seja, absorção de fótons de baixa energia e emissão de fótons de alta energia. O presente trabalho teve como objetivo a síntese de nanocompósitos do tipo core-shell, com a matriz CaTiO3 (CT) e dopagem com os íons terras raras Er3+ e Yb3+ nas mais variadas composições, para análise da propriedade fotoluminescente. As nanopartículas do core e do shell foram obtidas pelo Métodos dos Precursores Poliméricos. As amostras foram caracterizadas por Difração de Raios X (DRX) para caracterização estrutural, e foi constatada que todas as amostras apresentaram a estrutura perovsquita do tipo ortorrômbica. A caracterização por Microscopia Eletrônica de Transmissão (MET) não foi conclusiva quanto a formação do core-shell, sendo necessária a análise por Energia Dispersiva de Raios X (EDX), na qual verificou-se a presença das terras raras Er3+ e Yb3+ nas diferentes camadas. A espectroscopia de UV-Vis permitiu o cálculo do gap para as amostras core e shell. Os resultados de emissão FL foram utilizados para relacionar a espessura do shell e a intensidade da emissão. Por outro lado, ao estudar a conversão ascendente de energia, os materiais core apresentaram maior intensidade do que no core-shell; a melhor intensidade no core-shell foi verificada com a dopagem do core com Yb3+ e do shell com Yb3+ e Er3+, sugerindo a transferência de energia entre as camadas.

La déficience intellectuelle (DI) et les troubles du spectre autistique (ASD) sont deux troubles neurodéveloppementaux (NDD) présentant de nombreux chevauchements génétiques et phénotypiques ainsi qu’un biais de sexe important, avec plus de garçons atteints (1,4x plus pour la DI et 4x plus pour l'ASD). Au sein de notre laboratoire, le taux de diagnostic des patients souffrant de DI et/ou d’ASD est significativement plus élevé chez les filles que chez les garçons. De façon surprenante, nous n’avons pas observé de différence significative entre filles et garçons au niveau de la proportion de mutations pathogènes sur le chromosome X (5,3% versus 7,6%), confirmant ainsi que les mutations causales totalement pénétrantes sur ce chromosome ne peuvent pas expliquer la totalité de l’excès de garçons atteints de DI ou d'ASD. Nous avons donc choisi d’étudier une autre des hypothèses, plus environnementale, qui pourrait rendre le cerveau masculin plus susceptible au développement de NDD : le rôle des androgènes au cours du développement du cerveau. J'ai étudié l’effet de ces hormones masculines dans des précurseurs neuronaux humains (hNSCs) et observé que les androgènes augmentent la prolifération des hNSCs et les protègent contre la mort cellulaire en conditions stressantes. J'ai également mis en évidence que les androgènes, via leur récepteur (le récepteur aux androgènes), régulent une centaine de gènes dans les hNSCs avec, parmi eux, un enrichissement en gènes connus pour être différentiellement exprimés chez les individus avec ASD (dont NRCAM et FAM107A). La régulation de ces gènes par les androgènes pendant le développement du cerveau pourrait ainsi participer à la sensibilité accrue du cerveau masculin, exposé à d'autres facteurs génétiques et environnementaux, à développer une NDD. / Intellectual disability (ID) and autism spectrum disorders (ASD) are two common neurodevelopmental disorders (NDD) with many genetic and phenotypic overlaps. Another common feature is the existence of a gender bias, very strong for ASD (4 males for 1 female) and notable for ID (1.4:1). In our team, the diagnostic yield of patients affected by ID with or wihout ASD is significantly higher in girls than in boys. Surprisingly, we did not observe a significant difference between girls and boys in the proportion of pathogenic mutations on the X chromosome (5.3% versus 7.6%), confirming that rare and fully penetrant mutations on this chromosome can not explain the totality this male bias observed in ID and ASD. We have therefore chosen to study another hypothesis, more environmental, which could make the male brain more susceptible to develop NDD: the role of androgens during brain development. I studied the effect of these male hormones in human neuronal precursors (hNSCs) and observed that androgens increase the proliferation of hNSCs and protect them against cell death under stressful conditions. I also showed that androgens, via their receptor (the androgen receptor), regulate a hundred genes in hNSCs with, among them, an enrichment of genes known to be differentially expressed in individuals with ASD (e.g NRCAM and FAM107A). The regulation of these genes by androgens during brain development could thus contribute to the increased sensitivity of the male brain, exposed to other genetic and environmental factors, to develop an NDD.

La production de polyéthylène par la polymérisation de l'éthylène est un procédé industriel de grande importance. L'éthylène, issue de la pétrochimie contient des impuretés d'acétylène (1%), ce qui empoisonne le catalyseur de polymérisation, et donc le besoin d'un catalyseur qui soit sélectif pour hydrogéner l'acétylène en éthylène. Le composé intermétallique Al13Fe4 a été développé par Armbuster et al. en 2012 comme un catalyseur actif et sélectif pour la semi-hydrogénation de l'acétylène pour la production de polyéthylène. Il présente une structure cristalline avec des distances interatomiques Fe-Fe élevées et un faible nombre de coordination des atomes de fer, qui tombe sous le concept de "site isolation principle". Ce composé est également intéressant en raison de son faible coût (sans métaux nobles par rapport à Pd /Al2O3 catalyseurs industriels) et une faible toxicité. Cependant, il a été produit sous la forme de poudre non supportée par la méthode Czochralski ce qui limite son utilisation dans le domaine du génie catalytique. Dans ce contexte, supporter le catalyseur présente de nombreux avantages comme la facilité de séparation du catalyseur hétérogène à partir du mélange réactionnel obtenue par une variété de procédés telle que la filtration par exemple. Un autre avantage des catalyseurs supportés est la plus grande surface exposée du catalyseur ou dispersion. Etant donné que la catalyse est une réaction de surface, maximiser la surface d'un catalyseur, en le dispersant sur le support améliorera / optimisera l'activité catalytique. Les procédés de "chimie douce" dénommés Metal Organic Chemical Vapor Deposition (MOCVD) et Metal Organic Deposition (MOD) sont réputés pour être efficaces et économiquement compétitifs pour déposer des nanoparticules ou des films minces, à partir de précurseurs moléculaires appropriés. Notre travail vise donc à développer Al13Fe4 sous forme de films ou de nanoparticules supportées par MOCVD. La première étape pour atteindre cet objectif est le développement des précurseurs moléculaires d'aluminium métallique et de fer, dans des conditions compatibles suivies par codépôt ou dépôt séquentiel des deux précurseurs de Fe et Al pour former le composé intermétallique dans la bonne stœchiométrie. Parmi les nombreux précurseurs d'Al, le diméthyl ethylaminealane (DMEAA, [AlH3(NMe2Et)]) est utilisé en raison de sa pression de vapeur importante et des températures de dépôt faibles. En outre, l'absence de liaisons Al-O et Al-C conduit à la production de films sans impuretés carbone et oxygène. Cependant, des précurseurs moléculaires de fer pour le dépôt pour MOCVD de films de fer purs sont rares et moins développés. En dehors du pentacarbonyle de fer qui produit des films de fer pur, amidinates et guanidinates sont utilisés comme précurseurs de fer. Cependant, l'oxygène et des carbures sont présents dans des pourcentages élevés. Ainsi, l'objectif principal de ce travail de thèse est de concevoir et de synthétiser de nouveaux complexes moléculaires de fer qui servent de précurseurs pour la MOCVD. Dans ce travail, des nanoparticules de composé intermétallique Al13Fe4 sont préparées par réduction en solution et des films par dépôt séquentiel MOCVD en utilisant DMEAA et Fe(CO)5 en tant que précurseurs moléculaires. Les propriétés catalytiques ont été étudiées et ont montré d'une activité très peu active dans la réaction d'hydrogénation de l'acétylène: moins de 1% avant de se désactiver rapidement. La régénération sous hydrogène ou sous oxygène n'a qu'une faible restauration de l'activité. Les tests catalytiques ont été encore étendus à Al13Fe4 poudre préparée par réduction en solution ainsi que Al13Fe4 en poudre commerciale et a constaté que Al13Fe4 était non catalytiquement actif sous toutes ses formes (dans nos conditions de réaction) / Polyethylene production from the polymerization of ethylene is an industrial process of great importance. Ethylene stream for the polymerization of polyethylene is produced by the steam cracking of a wide range of hydrocarbon feedstock and usually contains acetylene impurities (1%) which poison the polymerization catalyst. The ethylene steam has to be purified by the selective semi-hydrogenation of acetylene which requires a catalyst with high selectivity to hydrogenate acetylene to ethylene. The intermetallic compound Al13Fe4 was introduced in 2012 by Armbuster et al. as an active and selective catalyst for the semi-hydrogenation of acetylene for polyethylene production. It has a crystal structure with high average inter-atomic distances Fe-Fe and a low coordination number of iron atoms, which falls under the concept of "site isolation principle". This compound is also attractive because of its low cost (without any noble metals compared to Pd/Al2O3 industrial catalysts) and low toxicity. However, it has been produced in the form of unsupported powder by the Czochralski method which limits its use in catalytic engineering. In this context, supporting the catalyst presents many advantages as the ease of separation of the heterogeneous catalyst from the reaction mixture. In contrast to homogeneous catalysts in which separation is often costly and difficult, separating the supported heterogeneous catalyst can be achieved by a variety of methods such as filtration for example. Another advantage of supported catalysts is the higher surface area of the catalyst. Since catalysis is a surface reaction, consequently, maximizing the surface area of a catalyst by distributing it over the support will enhance/optimize the catalytic activity.Chemical synthetic routes such as Metal Organic Chemical Vapor Deposition (MOCVD) and Metal Organic Deposition (MOD) referred as “Chimie douce” process are reputed to be flexible and economically competitive methods to prepare nanoparticles or thin films. Our work is thus aimed at developing Al13Fe4 as supported films or nanoparticles by MOCVD and/or MOD. The first step to meet our objective is the development of compatible molecular precursors of metallic aluminum and iron followed by MOCVD or MOD of those precursors to form the intermetallic compound in the good stoichiometry. Among the numerous aluminum MOCVD precursors used in the literature, dimethyl ethylamine alane (DMEAA, [AlH3(NMe2Et)]) is used due to its properties such as high vapor pressure and low deposition temperatures. Moreover, the absence of Al-O and Al-C bonds leads to the production of carbon and oxygen free films. However, iron molecular precursors for the MOCVD of pure iron films are scarce and less developed. Apart from iron pentacarbonyl that produces pure iron films, amidinates and guanidinates are used as iron precursors. However, oxygen and carbides impurities are present in high percentages. Thus the main objective of this Ph-D work is to design and synthesize novel and original iron molecular complexes that serve as precursors for the low temperature MOCVD of iron films. In this Ph-D work, nanoparticles of the intermetallic complex were prepared via solution reduction of novel Fe triazenide precursors and Al metal. Supported films were also prepared via sequential MOCVD by using DMEAA and Fe(CO)5 as molecular precursors. Its catalytic properties have been explored and showed that it is very little active in the hydrogenation reaction of acetylene. Regeneration under hydrogen or oxygen was not very successful and only some activity restored. The catalytic tests have been further extended to Al13Fe4 powder prepared by solution reduction as well as to commercial Al13Fe4 and found that Al13Fe4 was inactive catalytically in all forms (in our conditions of reactions)

In the present era where MEMS (Micro Electro-Mechanical Systems) technology is in¬evitable from the perspective of applications in non-silicon based micro-devices (such as biosensors, microfluidics, microvalves etc.), it is imperative to develop different micro¬fabrication technologies which are simple in operation, have low operational cost and high versatility in terms of incorporating different materials. The microfabrication tech¬nologies (e.g: bulk micromachining, surface micromachining, X-ray LIGA (lithoqraphie galvanoformung abformung) etc.), which exist commercially are mostly limited to sili¬con based technologies. They are either constrained in fabricating complex geometry in micro dimension or have high operational cost. Microstereolithography (MSL) is one such rapid prototyping technique, which can satisfy the above requirements to a larger extent. MSL h8B evolved in the l8Bt decade from conventional stereolithographic (SLA) technique, which involves the free-form microfabrication of a UV sensitive liquid resin layer by layer photo-polymerization process, when it is exposed to UV irradiation accord¬ing to the predefined CAD (Computer Aided Design). However, this technique is not limited to polymer microfabrication and it h8B an immense potential to fabricate com¬plex 3D structures of ceramics in micro dimension. In this thesis, the primary focus is on developing an in house built scanning b8Bed MSL system indigenously and to explore the possibility of micro fabrication of different materials (from polymer to ceramics involving different routes. In addition, polymer micro cantilever h8B been fabricated using this technique and its application to surface stress me8Burement h8B been demonstrated. The thesis comprises of eight chapters. The following section describes the summary of the individual chapters. Chapter 1 describes the introduction and background literature of this technol¬ogy. A brief review on MSL technology developed by various research groups and their achievements h8B been listed. Since photopolymerizable resin is the primary material to fabricate micro dimensional structures, the rate of photopolymerization is an impor¬tant phenomena which requires an attention before choosing the photopolymerizable resin. Further, this chapter also describes the photoinitiation principles and the type of photo initiators (PI) which help to photopolymerize the resin in order to fabricate micro dimensional polymer structures. In addition, this chapter also gives a glimpse of applications of this technology in fabrication of micro cantilever b8Bed sensors. The later part of the chapter focused on the microfabrication of ceramic from colloidal and met¬alorganic routes in brief. In Chapter 2, the design of the in house built MSL system and its working princi¬ples including various optical issues have been addressed. Several research groups have attempted to optimize photopolymerization parameters to incre8Be the throughput of the scanning b8Bed MSL systems through modified beam scanning techniques. Efforts in reducing the curing line width in order to get low feature size have been implemented through high numerical aperture (NA) optical setups. However, the intensity contour symmetry and the depth of field of focus have led to grossly non-vertical and non-uniform curing profiles. The focus of the work h8B been to exploit the rich potential of photoreactor scanning system in achieving desired fabrication modalities (minimum curing width, uniform depth profile, and vertical curing profile) even with a reduced NA optical setup and a single movable stage. The present study tries to manipulate to its advantage the effect of optimized lower photoinitiator (PI) concentration ([c]) in reduc¬ing the minimum curing width to 10-15 jJm, even with the higher spot size (21.4 jJm) rv through a judiciously chosen gmonomer UPIi' system. In this chapter, two different cl8BS of multifunctional acrylates (1,6 Hexane diol diacrylate (HDDA) and Trimethylol propanetriacrylate (TMPTA)) and one monofunctional methacrylate (methyl mathacry¬late (MMA)) have been chosen to explore their fabricability in micro dimensions using this MSL technology, by varying the various operational parameters including the type and the concentration of the PI. Chapter 3 deals with the application of this technology in micro cantilever based sensors. Microcantilever based sensors have been explored for several decades for their application in bio-molecular or explosive detection, chemical sensing etc. Due to the adsorption of molecular species on the cantilever surface, differential surface stress gen¬erates between the top and bottom surface of the cantilever. Depending on the type of stress (tensile or compressive) generated, the cantilever bends accordingly. The, novel diffraction based deflection method has been proposed in order to measure the deflection profile accurately for low dimensional structures. To prove this method, a dual mi¬crocantilever structure with sufficiently low gap (100 f.lm) has been fabricated using the developed MSL set up, such that diffraction occurs during transillumination by spherical wavefronts. Among the two micro cantilevers one was fabricated bent with a specific di¬mension with respect to the other. The cantilever material was chosen as poly HDDA for its low elastic modulus in order to achieve high sensitivity. From the obtained diffraction pattern, the bent profile of the each cross section of one cantilever corresponding to the other has been measured. This proposition will enable to measure surface stress at each cross section of the cantilever depending on the adsorbed analyte molecule adsorption. In Chapter 4, an effort has been made to improve the thermal, thermo mechanical and mechanical properties of the cantilever material (poly HDDA). The sensitivity of a micro cantilever depends precisely on fabrication and material aspects. The former de¬pends on the aspect ratio of the structure and can be controlled by fabrication parameters whereas the latter is inherently limited by the choice of the material. The properties of the material which impact the applicability are elastic modulus, Poisson's ratio, thermal expansion and thermal stability. Hence, these properties are studied for poly HDDA. However, the properties are not completely satisfactory for only poly HDDA (PHDDA) since, PHDDA will fail for high surface stress measurement (>275 mN/m). Hence, it h8B been copolymerized with MMA with an intention to improve the above mentioned properties and to determine the best composition for the micro cantilever application. It is observed by Finite Element Analysis (FEM) that Phpm5050 (HDDA:MMA(50:50)) composition shows optimum sensitivity when reliability is concerned for me8Buring high surface stress (275 mN/m). Chapter 5 bridges Chapter 2 and Chapter 6. Chapter 2 highlights the polymer mi¬crofabrication where8B, Chapter 6 deals with the microfabrication of ceramics. In order to fabricate ceramic micro objects by MSL, ceramic particles need to be blended with a photopolymerizable monomer followed by l8Ber induced photopolymerization . Under l8Ber irradiation, the monomer gets cured and traps the ceramic particles. Thus near net shape of green ceramic structures are 0 btained. After achieving the near net shape, it is important to remove the polymer, which acts 8B the binder for the green ceramic body. This debinding should be diffusion controlled so 8B to achieve defect free micro ceramics. Here two multifunctional monomers (HDDA and TMPTA) have been chosen 8B a b8Be monomer for fabricating ceramics. Therefore it is essential to understand the debinding mechanism of these polymers. However, (HDDA) h8B high shrinkage upon polymeriza¬tion with low rate of polymerization kinetics and low viscosity where8B the properties of (TMPTA) are exactly opposite. Hence, in order to optimize these properties, copoly¬merization of HDDA and TMPTA h8B been carried out for different compositions and their thermal properties have been investigated to understand the degradation mech¬anism. This chapter deals with the mechanism of thermal degradation by model free kinetic methods with an intention to determine the optimum composition of HDDA and TMPTA copolymer, to used 8B the b8Be monomer material for ceramic microfabrication. Besides, the debinding strategy is also discussed b8Bed on the degradation profile of the optimum composition. TH20S0(TMPTA: HDDA(20:S0)) is found to be the ideal com¬position to fabricate ceramic micro-component by MSL since its degradation is diffusion controlled in N 2 atmosphere. Chapter 6 describes the methodology of microfabrication of ceramics by the de-veloped MSL technique. A colloidal approach has been adopted to fabricate ceramics in micro-dimensions. Two different ceramics have been chosen, which have potential applications in structural (alumina) and functional (Lead Iron Niobate (PFN))aspects. Before fabricating ceramic micro-objects, ceramic particles need to be blended in the monomer suspension in the presence of dispersant at an optimum solids loading. Opti¬mization of solids loading is important in view of low dimensional shrinkage after sin¬tering. However, lower loading leads to higher shrinkage whereas higher loading would increase the viscosity of the suspension and make the suspension inconvenient to deal with. Hence, rheological studies have been carried out to optimize the solids loading and dispersant concentration. 40 vol% alumina and 35 vol% PFN are found to be the highest achievable solids loading for the chosen monomer (TH2080) composition. This chapter also describes the limitation involved in ceramic microfabrication depending on their scattering factors during laser irradiation. The chapter demonstrates the fabrica¬tion methodology of several complex ceramic(alumina and PFN) micro-objects by the in house built MSL instrument. Chapter 7 investigates the possibility of microfabrication of ceramics from metalor¬ganic precursor. In this route, titanium metal-organic (Ti-n butoxide) precursor has been chosen which is stabilized by the addition of chelating monomer (2-( methacryloyloxy) ethyl acetoacetate). Following this, the crosslinker and photoinitiators have been added to form Ti photoresist which is coated on top of the bare silicon substrate by spin coating to achieve specific thickness. The coated silicon wafer by the above photoresist has been patterned by selectively exposure in the MSL setup. The cured patterns are washed and heat treated at high temperature in order to 0 btain the net shape of the Ti02 pattern of polycrystalline rutile phase. It is observed this route is advantageous in terms of reduc¬ing curing dimension (curing width 14 f.lm) than the colloidal route (curing width more than 80 f.lm ) of fabrication of ceramics where the scattering factor greatly influences the dimensions of the feature size. The key findings and future aspects are summarized in the Chapter 8. The work reported in this thesis has been carried out by the candidate as part of the Ph.D. programme. He hopes that this would constitute a worthwhile contribution towards developing an MSL technique and its aspects in micro fabrication of polymer and ceramic structures of any complex shape and its possible applications in microdevices.

La dynamique du déclenchement des avalanches dans un milieu granulaire lentement incliné passe par trois phases; (1) des petits réarrangements locaux et indépendants de grains (2) suivis de mouvements collectifs, successifs et quasi-périodiques, appelés 'précurseurs' (3) finissant par une avalanche. Cette dynamique peut dépendre de nombreux paramètres. Dans cette thèse, nous avons étudié, par des mesures optiques et acoustiques, la réponse du milieu granulaire soumis à une inclinaison lente de son container. Nous avons déterminé l'importance du choix de la puissance du signal acoustique sur nos mesures. Nous avons observé l'effet de l'état de surface des grains sur l'apparition des précurseurs et sur l'occurrence de l'avalanche. Nous avons réalisé des cycles d'inclinaison allant de -θ à +θ se terminant par une avalanche . Nous avons mis en évidence l'influence de l'angle du cycle θ sur les précurseurs et l'angle d'avalanche final. Nous avons aussi étudié des milieux granulaires soumis à des taux d'humidité comprises entre 40 et 96, par des mesures optiques surfaciques et latérales. Nous avons montré que les angles d'avalanche et l'apparition des premiers précurseurs dépendent de la taille des grains mais aussi de l'humidité. Cette dépendance est liée aux forces de cohésion qui sont relativement plus élevées à forte humidité et qui compensent la force de gravité pour des petits grains. Enfin, nous avons montré l'importance d'une diffusion homogène de l'humidité dans le milieu sur son comportement. L'impact de la mouillabilité des grains a été aussi abordé. / The dynamics of avalanche triggering in a slowly inclined granular medium passes through three phases; (1) small local and independent rearrangements of grains (2) followed by collective, successive and quasi-periodic movements, called 'precursors' (3) ending in an avalanche. This dynamic can depend on many parameters. In this thesis, we have studied, by optical and acoustic measurements, the response of the granular medium subjected to a slow inclination of its container. We determined the importance of choosing the power of the acoustic signal on our measurements. We observed the effect of the grain surface condition on the occurrence of precursors and the occurrence of the avalanche. We performed tilted cycles ranging from -θ to +θ ending in an avalanche. We have demonstrated the influence of the θ cycle angle on the precursors and the final avalanche angle. We have also studied granular media with moisture contents between 40 and 96%, by surface and lateral optical measurements. We have shown that the avalanche angles and the appearance of the first precursors depend on the grain size but also the humidity. This dependence is related to cohesive forces that are relatively higher at high humidity and that compensate for the force of gravity for small grains. Finally, we have shown the importance of a homogeneous diffusion of moisture in the environment on its behavior. The impact of grain wettability was also discussed.

Chlorine has effectively reduced the prevalence of waterborne diseases, however there are secondary consequences to this public health advancement. Disinfection byproducts (DBPs) are chemicals formed when chlorine reacts with natural organic matter (NOM) in water. A new class of DBPs, halobenzoquinones (HBQs), has recently been identified and data suggests it could be potentially carcinogenic and up to 1000 times more toxic than some regulated DBPs. So far, in vitro studies have assessed HBQ toxicity without taking into account its transformation in cell media into potentially less toxic compounds. This study evaluated the toxic effects of one HBQ, 2,6-DCBQ, and its transformed derivatives on colon epithelial and liver hepatoma cell lines by measuring intracellular reactive oxygen species production and cell viability post-DCBQ exposure. In addition, to better quantify the trade-off between exposure to waterborne pathogens and 2,6-DCBQ, the inactivation of a virus indicator (MS2), and formation of DCBQ were determined in chlorinated surface waters. Dose-dependent toxic effects were observed in both cell lines and transformed DCBQs were observed to be less toxic than their parent compound. MS2 inactivation occurred immediately post-chlorination, but DCBQ was detected simultaneously. Such findings indicate that this compound is toxic to human cells, including colon epithelial cells, which may be pertinent due to the possible association between chlorinated waters and colon cancer. Findings also suggest this DBP may be relevant in developing countries because HBQs may form in point-of-use chlorinated drinking waters. Furthermore, observed reduction in toxicity of media-transformed DCBQs calls current literature on HBQ toxicity into question.

[pt] O Ácido Húmico (AH) é uma fração orgânica obtida em solos, corpos hídricos bem como em matrizes carbonáceas. Nos últimos anos o interesse associado a esta substância vem crescendo progressivamente à medida que novas aplicações são descobertas, tais como: fertilizantes, recuperação de áreas degradadas e tratamento de efluentes contaminados com metais. As principais características dos AH são dependentes do método de extração e da matriz escolhida, posto que se pode extraí-lo de uma ampla gama de matérias primas, assim como por meio de diferentes métodos. Dentro deste contexto, o objetivo principal do presente trabalho pretende avaliar o potencial de extração de ácido húmico a partir de diferentes precursores carbonáceos. Foram utilizadas três matrizes carbonáceas distintas: rejeito de carvão mineral (RCM), coque mineral (CM) e coque verde de petróleo (CVP). Além deste estudo experimental foram apresentados alguns resultados de estudo semelhante disponível na literatura. O método de extração utilizado foi adaptado de Trompowski et al (2005), e a caracterização foi feita utilizando-se técnicas de ICP-OES, CNHS, MEV/EDS, FTIR e Difração de Raio-X. A eficiência da extração, em termos de recuperação em massa, variou, significativamente, em função do método adotado, sendo os melhores resultados associados ao rejeito de carvão mineral (17,0 porcento), ao passo que a menor eficiência está relacionada ao coque verde de petróleo, após destilação (0,2 porcento). A extração a partir do coque verde de petróleo, como recebido, é inviável em função da sua imiscibilidade com a solução de ácido nítrico. Os resultados obtidos a partir do FTIR foram satisfatórios para todos os AH analisados, apresentando bandas características de AH e compatíveis com o indicado na literatura. Os resultados da análise de ICP-OES apresentaram baixa presença de metais e elementos traços para o AH oriundo do coque mineral. No que diz respeito ao ácido húmico extraído do rejeito de carvão mineral, que apresentou a maior concentração inicial de metais, principalmente ferro, foi implementado, com sucesso, uma purificação utilizando ácido nítrico. Com base nos resultados obtidos é possível afirmar que a utilização de diferente precursores carbonosos permitiu a extração de AH com características semelhantes aqueles citados na literatura e extraídos de outras fontes. / [en] The humic acid (HA) is an organic fraction that can be found in soil and watercourses as well as in carbonaceous matrices. In recent years the interest associated with this substance has been growing steadily as new applications are discovered, such as fertilizers, remediation of degraded areas and treatment of wastewater contaminated with metals. The main features of HA are dependent on the method of extraction and the chosen matrix, since it can be extract from a wide range of raw materials, as well as by different methods. Within this context, the main objective of this work is related to an assessment of the potential of extracting humic acid from different carbonaceous precursors. three different carbonaceous matrices were used: coal tailings (RCM), coke (CM) and green petroleum coke (CVP). Besides this experimental study some results of a similar study available in the literature were presented. The extraction method used was adapted from Trompowski et al, and the characterization was done using ICP- OES techniques, CNHS, MEV / EDS and FTIR. The extraction efficiency, in terms of mass recovery, significantly varied depending on the method used, the best results being associated with coal tailings (17.0 percent), while lower efficiency relates to the calcinated petrocoke after distillation (0.2 percent). The extraction from green petroleum coke, as received, is unfeasible due to its immiscibility with the nitric acid solution. The results obtained from FTIR were satisfactory for all the HA analyzed, displaying bands consistent with those from HA and compatible with bands shown in the literature. The results of the analysis of ICP-OES showed a low presence of metals and trace elements coming from the HA for coke. With respect to the extracted humic acid from coal tailings, which showed the highest initial concentration of metals, particularly iron, was successfully implemented, a purification with nitric acid. Based on the results obtained it can be stated that the use of different carbonaceous precursors allowed the extraction of humic acid with similar characteristics as cited in the literature and those obtained from other sources.

Advances in neonatology have led to increased numbers of high-risk neonates surviving and intensified interest in the developmental outcomes of this population. In the South African context prematurity and low birth weight are the most common causes of death in the perinatal period and the same risk factors that contribute to infant mortality also contribute to the surviving infants’ increased risk for developmental delays. As a result of the interacting biological and environmental risk factors of prematurity, low birth weight, poverty and HIV and AIDS in the South African context Kangaroo Mother Care (KMC) has been developed as best practice to promote infant survival and to facilitate mother-infant attachment. Mother-infant attachment may lead to synchronous interaction patterns between the mother and infant which forms the basis of early communication development. Early communication intervention (ECI) services are recommended as early as possible as high-risk infants are especially at risk for feeding difficulties and communication developmental delays. It is, however, not clear what the content of an ECI programme should be and how it should be implemented according to the changing communication and feeding developmental needs of the infant while receiving KMC. There appears to be a dearth of research on the earliest stages of communication development in high-risk neonates, which should form the foundation of such a programme. A descriptive survey was conducted to describe the development of 25 high-risk infants and their mothers’ changing needs from admission to discharge from a KMC unit. Each participant and mother dyad was followed up over an average of 11 days of data collection with three to four data collection sessions. Data was collected by means of direct observation during routine care-giving activities. The different developmental subsystems of the participants’ feeding, communication, neuro-behavioural organization and mother-neonate interaction were described. The results demonstrated that subtle, but definite changes could be observed in the participants’ development. Development in all the different areas occurred over time as the participants progressed through the three developmental states of the in-turned state, coming-out state and reciprocity state. As the participants progressed during the 11 days of data collection and were increasingly able to attend to their environment, they also developed the ability to regulate and organize their own behaviour in order to develop more complex communication, feeding and interaction skills with their mothers. The functioning of the participants’ sensory systems developed in a specific order namely tactile, auditory and then visual. Although the participants developed consistently throughout their stay in the KMC unit, mother-neonate interaction never reached optimal levels. The importance of an individualized training programme for each mother is reflected in the finding that the neonate’s developmental level and progress needs to be considered when implementing the ECI programme. The need for speech-language therapy involvement in KMC is emphasized in the light of a shortage of practicing speech-language therapists in South Africa. It is therefore imperative that the prevention of communication delays and feeding difficulties in high-risk neonates as well as parent training assume priority. / Dissertation (MCommunication Pathology)--University of Pretoria, 2008. / Speech-Language Pathology and Audiology / unrestricted

This study evaluated the combination of ozone and granular activated carbon (GAC) treatment for the removal of sulfide and disinfection byproduct (DBP) precursors in drinking water at the pilot-scale. The research conducted was performed at the Auxiliary (Aux) and Main Water Treatment Plants (WTPs) in Sanford, Florida. Both WTPs rely upon groundwater sources that contain total sulfide ranging from 0.02 to 2.35 mg/L and total organic carbon (TOC) ranging from 0.61 to 2.20 mg/L. The Aux WTP’s raw water contains, on average, 88% more sulfide and 24% more TOC than the Main WTP. Haloacetic acids (HAA5) and total trihalomethanes (TTHMs) comprise the regulated forms of DBPs. HAA5 are consistently below the maximum contaminant level (MCL) of 60 μg/L, while TTHM ranges from 70 to 110 μg/L, at times exceeding the MCL of 80 μg/L in the distribution system. Ozone alone removed total sulfide and reduced UV-254 by about 60% at the Aux Plant and 35% at the Main Plant. Producing an ozone residual of 0.50 mg/L prevented the formation of bromate while removing approximately 35 to 60% concentration of DBP precursors as measured by UV-254. Operating the GAC unit at an empty bed contact time (EBCT) of 10 minutes for the Aux Plant and 5.5 minutes for the Main Plant resulted in 75% and 53% of UV-254 reduction, respectively. The average 120 hour TTHM formation potential for the Aux and Main Plants were 66 μg/L and 52 μg/L, respectively, after treatment by ozone and GAC. GAC exhaustion was deemed to have occurred after seven weeks for the Aux Plant and eleven weeks for the Main Plant. The GAC columns operated in three phases: an adsorption phase, a transitional phase, and a biologically activated carbon (BAC) phase. The GAC adsorption phase was found to produce the lowest TTHMs; however, TTHMs remained less than 80 μg/L during the BAC stage at each plant. BAC exhaustion did not occur iv during the course of this study. Ozone-GAC reduced chlorine demand by 73% for the Aux Plant and 10% for the Main Plant.