Le dépôt par électrophorèse, technique éclectique et prometteuse, est bien connue pour permettre la production de films déposés de haute qualité et d'épaisseur contrôlée. Au vu de ces possibilités, la technique EPD a été appliquée avec succès lors de ce présent travail de thèse de doctorat pour produire des couches à base de zircone yttriée orientées vers des applications comme électrolyte solide dans les piles à combustibles. Nous avons testé deux techniques simples, facilement transférables à la production industrielle : La sérigraphie et le dépôt par électrophorèse. Les caractéristiques microstructurales de ces couches se reflètent sur leur comportement électrique. Notamment, les couches électrophorétiques possèdent des valeurs de conductivité plus élevées et proches des valeurs théoriques. Ces valeurs couplées au fait de pouvoir développer des couches d'épaisseur faible contrôlée (de l'ordre de la dizaine de µm), démontrent combien le dépôt par électrophorèse est une réponse valide aux demandes d'amélioration des caractéristiques des couches d'électrolytique.

Dissertation (Ph.D.)--University of South Florida, 2009. / Title from PDF of title page. Document formatted into pages; contains 86 pages. Includes vita. Includes bibliographical references.

Dissertation (Ph.D.)--University of South Florida, 2009. / Includes vita. Includes bibliographical references. Also available online.

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The yeast species, Saccharomyces cerevisiae and S. bayanus are well known for the key role they play during alcoholic fermentation in both wine and beer industries. These yeasts are available in pure active dried form and can be used to produce different wine styles and to manage quality. There are more than 200 commercial wine yeast strains on the market and include naturally isolated strains and hybrids. With all these commercial yeasts available, strain authenticity is very important to the manufacturer of active dried wine yeasts (ADWY) because it can prevent commercial losses and maintain market credibility. It is as important to the winemaker as it may impact wine quality. Various traditional and molecular techniques have been successfully applied to perform quality control of wine yeast strains. The aims of this study were to evaluate electrophoretic karyotyping (CHEF) and PCRbased methods to distinguish between Saccharomyces wine yeast strains and to establish a database containing molecular profiles of commercial strains. CHEF karyotyping was chosen because it is generally used in the wine industry to distinguish between wine yeast strains, but can be time-consuming. Alternatively, PCR-based methods are considered to be reliable and fast. These PCR methods included the evaluation of interdelta regions, multiplex-PCR of miniand microsatellites, MET2 gene RFLP analysis and the use of several species-specific primers. In this study, 62 commercial wine yeast strains, were randomly selected from various manufacturers of ADWY, and two reference strains, S. bayanus CBS 380 and S. cerevisiae CBS 1171, were evaluated. CHEF karyotyping could successfully differentiate between all 64 yeast strains. The two primer sets used for interdelta amplifications, delta1-2 and delta12-21, yielded 59 and 62 profiles, respectively. Yeast strains considered to be similar or identical according to interdelta amplification results, were resolved with CHEF karyotyping. CHEF karyotyping was proven to be more accurate than interdelta amplifications in distinguishing between commercial wine yeast strains. However, the results of interdelta amplifications were very useful and less time-consuming. The multiplex-PCR of mini- and microsatellite primers only succeeded in identifying a specific band within 55 of the 64 yeast strains including the S. cerevisiae reference strain, a possible indication of species specificity. However, oenological designation using MET2 gene RFLP analysis and species-specific primers indicated that all the commercial strains in this study had a S. cerevisiae ancestry. Restriction analysis of the MET2 gene with EcoRI also successfully identified AWRI Fusion and Zymaflore X5 as hybrid yeast strains. A wine yeast database was created and contains three libraries, i.e. CHEF karyotypes, delta1-2 and delta12-21 electrophoretic profiles. The database was proven to be functional and showed great accuracy in grouping and identifying test strains. The database has many possible applications, but there is still some optimisation and refinement needed. / AFRIKAANSE OPSOMMING: Die Saccharomyces sensu stricto kompleks, is bekend vir die belangrike rol wat hierdie giste speel tydens alkoholiese fermentasie in biede wyn en bier industrieë. Dit is om hierdie rede dat kelders rein aktief gedroogte wyngis gebruik vir die produksie van spesifieke wynstyle, asook kwaliteit. Daar is meer as 200 kommersiële wyngiste op die mark beskikbaar en dit sluit natuurlike isolate en hibriede in. Daarom is gisras verifikasie baie belangrik vir die vervaardiger van aktief gedroogde wyngiste asook die wynmaker om finansiële verliese te voorkom en mark vertrouenswaardigheid te handhaaf. Verskeie tradisionele en molekulêre metodes word suksesvol toegepas vir gehalte beheer van die gisrasse. Die doel van hierdie studie was om elektroforetiese kariotipering (CHEF) en PKR gebaseerde tegnieke se vermoë om tussen Saccharomyces wyngiste te onderskei, te ondersoek. Ook deel van die doelwitte was om ‘n databasis te skep wat die verskillende elektroforetiese profiele van die kommersiële gisrasse bevat. Tydens hierdie studie is 62 kommersiële gisrasse van verskeie vervaardigers ewekansig geselekteer. Saccharomyces bayanus CBS 380 en S. cerevisiae CBS 1171 is as verwysingsrasse gebruik. Elektroforetiese kariotipering (CHEF) is gekies omdat dit een van die mees algemeenste tegnieke is wat gebruik word om tussen wyngiste te onderskei, maar dit word as tydrowend en arbeidsintensief beskou. As ‘n alternatief is daar na PKR gebaseerde tegnieke gekyk. Hierdie tegnieke word as betroubaar en vinnig beskou. Verskeie PKR gebaseerde tegnieke is ondersoek, naamlik PKR van interdelta areas, multipleks-PKR van mini- en mikrosatelliete, MET2 geen RFLP analise en die gebruik van spesie-spesifieke inleiers. Interdelta amplifikasies en mini- en makrosatelliet inleiers is geselekteer as gevolg van hul vermoë om Saccharomyces wyngiste tot op spesie en ras vlak te onderskei. Die MET2 geen en spesie-spesifieke inleiers is geselekteer om die kommersiele wyngis as S. cerevisiae, S. bayanus of as hibriede te klassifiseer. CHEF kariotipering kon tussen al 64 giste onderskeid tref. Die twee stelle inleiers wat vir interdelta amplifikasie gebruik was, delta1-2 en delta12-21, het onderskeidelik 59 en 62 profiele gelewer. Gis rasse wat identiese profiele met die delta inleiers gelewer het, kon egter met CHEF kariotipering onderskei word. Die resultate het getoon dat CHEF kariotipering beter tussen die kommersiële wyngiste kon onderskei as die interdelta amplifikasies, maar dat die interdelta amplifikasies nogsteeds goeie onderskeiding toon en dat dit minder tydrowend is. Die multipleks-PKR van mini- en mikrosatelliete kon slegs ‘n enkele band in 55 van die 64 giste uit lig. ‘n Moontlike aanduiding van spesie spesifiekheid. Die oenologiese groepering volgens MET2 geen analise en spesies-spesifieke inleiers dui aan dat al die kommersiele wyngiste wat in hierdie studie gebruik is, moontlik van S. cerevisiae afkomstig is. Restriksie analise van die MET2 geen met EcoRI het ook AWRI Fusion en Zymaflore X5 as hibriede geïdentifiseer. Die CHEF kariotipes en interdelta elektroforetiese profiele is gebruik om ‘n databasis van die kommersiële Saccharomyces wyngiste op te stel. Die databasis is funksioneel en het die toets rasse akkuraat geïdentifiseer en korrek gegroepeer. Die databasis moet egter nog verdere optimisering en verfyning ondergaan.

Orientadores: Maria Isabel Nogueira Cano, Carlos Henrique Inacio Ramos / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-08T19:46:21Z (GMT). No. of bitstreams: 1 Lira_CristinaBragadeBrito_D.pdf: 9068778 bytes, checksum: 7561201fa37b1109dc7803fb6173aad0 (MD5) Previous issue date: 2007 / Resumo: A leishmaniose é uma doença parasitária que foi considerada pela Organização Mundial de Saúde como uma doença de Categoria 1, pois para a mesma não existem formas de controle, diagnóstico ou terapia eficientes. Os parasitas do gênero Leishmania (família Trypanosomatidae) são agentes etiológicos da leishmaniose e possuem cromossomos lineares com extremidades teloméricas. Os telômeros são complexos nucleoproteicos essenciais para manuntenção da estabilidade do genoma e viabilidade celular. Devido à importância das proteínas teloméricas na manutenção dessas estruturas, elas têm sido considerados bons alvos para a terapia anticâncer e antiparasitária. Sendo assim, o objetivo deste trabalho foi identificar proteínas que se associam aos telômeros de Leishmania amazonensis. Três metodologias diferentes foram utilizadas para antigir este objetivo: (i) purificação de proteínas teloméricas a partir de extratos de L. amazonensis, (ii) busca no banco de dados de Leishmania por proteínas homólogas que apresentassem domínios de ligação ao DNA do tipo Myb, e (iii) seleção genética em levedura (sistema mono-híbrido). A purificação de proteínas teloméricas a partir de extratos nucleares de L. amazonensis resultou no isolamento da proteína LaRbp38. Ensaios in vitro de interação proteína-DNA e ensaios in vivo (imunoprecipitação de cromatina) comprovaram a interação de LaRbp38 com DNA telomérico, DNA rico em GT e DNA do cinetoplasto. LaRbp38 pode ser considerada um bom alvo para a terapia antiparasitária pois é uma proteína exclusiva de tripanosomatídeos e seu homólogo em T. brucei é essencial para a sobrevivência do parasita. Para dar início a experimentos de caracterização da estrutura dessa proteína, LaRbp38 foi expressa em bactérias. Como a proteína permaneceu na fração insolúvel, experimentos preliminares de renovelamento foram feitos mostrando que a proteína necessita da presença de DNA, ou de moléculas análogas, para se renovelar in vitro. As buscas no banco de dados de L. major resultaram no descobrimento de uma lista de proteínas que apresentam domínio de ligação ao DNA do tipo Myb. Uma proteína foi escolhida e sua homóloga em L. amazonensis foi denominada LaTBP1. O domínio Myb de LaTBP1 se localiza na porção central da proteína e apresenta alta similaridade de seqüência com domínios Myb encontrados em fatores de transcrição to tipo TFIIIB, proto-oncogene c-MYB e membros da família de proteínas teloméricas Rap1p. Ensaios de interação proteína-DNA e de imunoprecipitação de cromatina confirmaram que LaTBP1 interage tanto com o DNA telomérico quanto com DNAs ricos em GT. Prefências por estes dois tipos de DNAs são apresentadas pelas proteínas teloméricas Rap1, Taz1 e TEBP1, descritas em leveduras e eucariotos superiores. A utilização do sistema mono-híbrido para identificação de proteínas teloméricas de Leishmania resultou em uma lista de proteínas candidatas. A possível função telomérica das mesmas foi inferida com base na homologia de seqüência com proteínas já descritas e em testes de interação proteína-DNA in vitro utilizando-se extratos das leveduras recombinantes. Apesar desses resultados serem promissores, análises mais detalhadas são necessárias para confirmar estas interações. Concluindo, as três metodologias se mostraram eficazes para a identificação de proteínas teloméricas e a utilização das mesmas resultou na identificação de diversas proteínas teloméricas, algumas delas ainda hipotéticas / Abstract: Leishmaniasis is a parasitic disease that was classified by World Health Organization as a Category 1 disease because there are no effective control programs or therapeutics to this disease. Parasites from the Leishmania genus are the ethiologic agents of leishmaniasis and they possess linear chromosomes with telomeric ends. Telomeres are nucleoprotein specialized nucleoprotein complexes essential for maintaining chromosomal stability and cell viability. Since telomeric proteins are essential for the maintenance of telomeres, they could be considered good targets for anticancer and antiparasitic drugs. Therefore, the goal of this work was to identify Leishmania amazonensis proteins that interact with the telomeric DNA. Three methodologies were used the achive this goal: (i) purification of telomeric proteins from nuclear extracts of L. amazonensis, (ii) Leishmania genome database mining for protein containing a Myb-like domain, and (iii) use of One-hybrid system (Clontech). The search for telomeric proteins in nuclear extracts of L. amazonensis resulted in the identification of LaRbp38. EMSA and immunoprecipitation assays were used to attest LaRbp38 binding to telomeric, GT-rich and kinetoplast DNAs, both in vitro and in vivo. LaRbp38 could be considered a good drug target for antiparasitic therapy since it is exclusive of trypanosomatids and itshomologue in T. brucei is essential for parasite survival. In order to characterize structurally this protein, LaRbp38 was expressed in bacteria. The protein was present in the insoluble fraction of the bacterial lysate. Therefore, preliminary experiments of refolding were done. LaRbp38 seems to need DNA, or analog molecules, in order to correctly refold in vitro. Data-mining in the L. major genome resulted on a list of proteins bearing a Myb-like domain. One protein was chosen and its L. amazonensis homologue was termed LaTBP1. LaTBP1 Myb-like domain is centrally localized and shares sequence similarities with Myb-like domains found on transcription factors TFIIIB and c-MYB, and with the RAP1 telomeric proteins. Competition and chromatin immunoprecipitation assays confirmed the specificity of LaTBP1 for telomeric and GT-rich DNAs. This binding specifities are also found on the telomeric proteins Rap1, Taz1 and TEBP1, described in yeast and higher eukaryotes. A list of proteins with a putative telomeric function was generated after the use of the Onehybrid system. Sequence analysis (search for homologues in other organisms) and EMSA, done with protein extract of recombinant yeast, were used to infer a telomeric function for the proteins found by this methodology. Although the results are encouraging, detailed analysis are necessary to validate the interactions. In conclusion, the three methodologies were usefull for the identification of telomeric proteins. This work resulted in the identification of several telomeric candidate proteins / Doutorado / Genetica de Microorganismos / Doutor em Genetica e Biologia Molecular

L’enregistrement et la stimulation in vivo de l’activité neuronale peuvent aussi bien servir pour la recherche médicale que pour les interfaces cerveau-machine. Les dispositifs à base d’électronique organique sont de prometteurs candidats pour ce faire, grâce à leur flexibilité et leur biocompatibilité. Le contrôle local de l’activité neuronale est la clé de nombreuses stratégies thérapeutiques visant à traiter les troubles neurologiques. Une solution idéale serait donc de fabriquer un dispositif capable de détecter l’activité neuronale et, en réponse, d’injecter des molécules endogènes. L’un des objectifs de cette thèse est de s’attaquer à cette problématique à l’aide d’un dispositif permettant à la fois de stimuler les cellules, et de mesurer l’activité neuronale, au même endroit, à l’échelle cellulaire. Nous présentons un dispositif organique capable de délivrer précisément des neurotransmetteurs in vitro et in vivo. En convertissant un signal électrique en la délivrance de neurotransmetteurs, le dispositif mime le fonctionnement d’une synapse. Le neurotransmetteur inhibiteur, l’acide γ- aminobutyrique (GABA), est relargué au niveau des électrodes d’enregistrement par l’activation d’une pompe ionique électronique. L’injection du GABA engendre l’arrêt de l’activité épileptique qui a été enregistré au niveau des électrodes. Des dispositifs multifonctionnels ouvrent de nombreuses possibilités, incluant des dispositifs thérapeutiques avec des boucles de retour, avec lesquels l’enregistrement local de signaux régule la délivrance d’agents thérapeutiques. De plus, nous avons également réalisé pendant cette thèse l’intégration de transistors organiques sur un film organique ultra fin, pour mesurer les signaux électrophysiologiques in vivo à la surface d’un cerveau de rat. Le dispositif, implanté de façon épidurale, montre des résultats surpassant certains dispositifs subduraux de taille similaire, permettant ainsi une approche moins invasive et efficace pour mesurer l’activité neuronale. / Recordings and stimulation of in vivo neural activity are necessary for diagnostic purposes and for brain-machine interfaces. Organic electronic devices constitute a promising candidate due to their mechanical flexibility and biocompatibility. Local control of neuronal activity is central to many therapeutic strategies aiming to treat neurological disorders. Arguably, the best solution would make use of endogenous highly localized and specialized regulatory mechanisms of neuronal activity, and an ideal therapeutic technology should sense activity and deliver endogenous molecules simultaneously to achieve the most efficient feedback regulation. Thus, there is a need for novel devices to specifically interface nerve cells. Here, we demonstrate an organic electronic device capable of precisely delivering neurotransmit- ters in vitro and in vivo. In converting electronic addressing into delivery of neurotransmit- ters, the device mimics the nerve synapse. The inhibitory neurotransmitter, -aminobutyric acid (GABA), was actively delivered and stopped epileptiform activity, recorded simultaneously and colocally. These multifunctional devices create a range of opportunities, including implantable therapeutic devices with automated feedback, where locally recorded signals regulate local release of specific therapeutic agents. In addition, we demonstrate the engineering of an organic electrochemical transistor embedded in an ultrathin organic film designed to record electrophysiological signals on the surface of the brain. The device was applied in vivo and epidurally implanted could reach capabilities beyond similar sized electrodes allowing minimally invasive monitoring of brain activity.

No description available.

This diploma thesis deals with the preparation and characterization of negatively charged catanionic vesicular systems and their combination with selected polycations. The catanionic vesicular system was prepared by mixing of two oppositely charged surfactants SDS and CTAB. The negative charge as well as the stability of the vesicular system was provided by the incorporation of phosphatidic acid. Polycations, DEAE and TMC, have been selected for use in a pharmaceutical applications. Characterization of the prepared systems was performed by measuring DLS and ELS. The results indicate that we were able to prepare stable negatively charged vesicles that were eligible to non-covalently interact with selected polycations.

Ces travaux de thèse portent sur la synthèse de particules hybrides à partir de pigments inorganiques pour la formulation d’encres électrophorétiques colorées. Les pigments doivent répondre à un cahier des charges spécifique à ce type d’application. Ils doivent avoir une taille sub-micronique, une faible densité et un haut indice de réfraction afin d’exalter les phénomènes de diffusion. Les pigments bleus et cyan de structure spinelle CoAl2O4 et NiAl2O4 ont été synthétisés par voie Pechini. Dans les deux cas, des phénomènes de démixtion influençant la couleur ont été observés. Cependant, de par la différence de rayon ionique entre le Co2+ et le Ni2+ (rCo2+ < rNi2+), les origines en sont différentes. Dans le premier cas il a fallu éliminer les ions Co3+ stabilisés en site [6] pour obtenir une phase pure où la majorité des ions cobalt occupent les sites [4]. Dans le second cas l’ajout d’ions Al3+ a été nécessaire pour stabiliser une phase spinelle pure en présence de lacunes cationiques et d’ions Ni2+ occupant partiellement les sites [4] et [6]. Ensuite, nous avons développé des pigments magenta et jaunes de structure olivine explorant la solution solide LiCoxNi1-xPO4. Dans ces composés, l’étude des transitions électroniques corrélées à la structure et à l’environnement des ions chromophores Ni2+ et Co2+ en site [6] a permis de montrer des champs cristallins proches et un effet néphélauxétique presque identique. Finalement l’analyse de l’état de valence du chrome dans les structures de type rutile SnxCr1-xO2 a permis de synthétiser des pigments violets. Dans un second temps, la surface des pigments a été modifiée avec des chaines silanes de type n-trimethoxysilane afin de favoriser la dispersion des pigments dans un milieu apolaire. Puis les pigments modifiés ont été polymérisés dans l’Isopar G par polymérisation radicalaire contrôlée par les nitroxydes avec du méthacrylate de méthyle afin de diminuer la densité globale des particules hybrides et ainsi obtenir des encres stables. L’étude de l’influence des conditions expérimentales a été effectuée sur chaque pigment afin de formuler des encres colorées et chargées sans ajout de contrôleur de charge. La réalisation d’un dispositif électrophorétique à deux couleurs bleu et blanc a finalement pu être développé. / This work deals with the hybrid particles synthesis, using inorganic pigment for the coloured electrophoretic inks formulation. To comply with this type of application, pigments must have a sub-micrometer size, a low density and a high refractive index in order to exalt the diffusion phenomena. Blue and cyan spinel structure pigments CoAl2O4 and NiAl2O4 have been synthesized by Pechini process. In both these oxides, steric and electronic effects allowed stabilizing pure phases with enhanced colouring effects. In the case of CoAl2O4, we have to avoid the occurrence of Co3+ (LS) whereas for NiAl2O4, excess of Al3+ is necessary to get pure phases with nanosized crystallites. Then, magenta and yellow olivine structure pigments have been developed with the exploration of the solid solution LiCoxNi1-xPO4. In these compounds, the study of the electronic transitions combined with Ni2+ and Co2+ chromophores ions structure and environment in [6] site leads to comparable crystal field and so an almost similar nephelauxetic effect for both ions. Finally, the investigation of the valence state and the environment of chromium in rutile type structure Sn1-xCrxO2 allowed the synthesis of purple pigments. In a second part, the pigment surface has been modified with n-trimethoxysilane chains to improve the pigment dispersion in apolar media. Then, modified pigments have been polymerised in Isopar-G by nitroxyde mediated radical polymerisation with methyl methacrylate to decrease the hybrids density and to obtain stable inks. The impact of the experimental conditions has been studied on each pigments in order to formulate coloured and charged inks without any charge control agent. A two-colour electrophoretic device (blue/white) has been finally tested.

An electrophoretic deposition (EPD) process of micro-quartz (MQ) powder is applied to carbon fibers (CFs) with the aim to enhance their interfacial bond to cementitious matrices and to investigate its influence on the microstructural and mechanical properties of the CFs itself. The electrophoretic mobility of the MQ particles with negative charge in aqueous media was confirmed by potential sweep experiments and zeta-potential measurements. High amounts of MQ were successfully deposited onto the fiber surface, as proven by scanning electron microscopy. Single-fiber tension tests and thermogravimetric analysis showed that EPD treatment had little impact on the tensile properties and thermal stability of the modified fibers. However, storing the CFs in cement pore solution impaired temperature stability of untreated and modified fibers. X-ray diffraction and Raman spectroscopy reveal specific changes of CF's microstructure upon EPD treatment and immersion in pore solution. Single-fiber pullout tests showed that the pullout resistance of MQ-modified CFs was enhanced, relative to untreated CFs. This augmentation can be explained by an enhanced interlocking mechanisms between CF and matrix due to the deposited quartz particles on the CF surface.