Les emballages alimentaires et pharmaceutiques doivent de nos jours répondre à de nombreux critères : ils doivent non seulement préserver le produit emballé, mais également être inoffensifs, économes en énergie et jetables. Les polymères barrières ont permis de répondre à ces besoins, en offrant des alternatives à des matériaux plus demandeurs en énergie et plus lourds tels que le verre ou les métaux, tout en conservant une faible perméabilité à l’eau et/ou à l’oxygène. Parmi la grande variété de polymères barrières existants, les copolymères du poly(chlorure de vinylidène) (PVDC) offrent une protection plus complète aux contaminants extérieurs, grâce à leurs faibles perméabilités à l’eau et à l’oxygène. Cependant, les films de PVDC sont sujets à des processus de dégradation ayant lieu lors du thermoformage ou sous exposition aux rayonnements UV. Ces effets sont encore plus prononcés dans le cas de films obtenus à partir de latex, dû à des quantités plus importantes d’additifs qui accentueraient les phénomènes de dégradation du polymère. Par conséquent, la synthèse de latex à base de PVDC pour des applications en tant que films barrières aux stabilités thermique et UV améliorées revêt un grand intérêt. Des latex composites à base de PVDC ont tout d’abord été synthétisés en présence de latex semences à fonctionnalité époxy en vue d’améliorer la stabilité thermique du polymère. En effet, les groupements époxy jouent le rôle de stabilisants thermiques en piégeant le chlorure d’hydrogène, dégagé lors du thermoformage et présentant un effet catalytique indirect sur le processus de dégradation du polymère. Dans une première étape, des latex semences à fonctionnalité époxy ont été synthétisés par copolymérisation en émulsion du methacrylate de glycidyle (GMA) et du methacrylate de butyle (BMA). Lors d’une seconde étape, la copolymérisation en émulsion ensemencée du chlorure de vinylidene et de l’acrylate de méthyle a été effectuée en présence des semences de poly(GMA-co-BMA). Des analyses thermogravimétriques effectuées sur les échantillons composites ont mis en évidence le rôle de stabilisant thermique joué par les fonctions époxy. La seconde partie du projet concerne la synthèse de latex hybrides à base d’oxyde de cérium (CeO2) afin d’améliorer la résistance du PVDC aux rayonnements UV. Les nanoparticules d’oxyde de cérium sont en effet attrayantes en tant que stabilisants UV en raison de leur haute absorption des rayonnements UV et d'une faible activité photocatalytique. Cependant, étant donné l’incompatibilité intrinsèque entre les phases inorganique et organique, la synthèse de latex hybrides requiert souvent une étape préliminaire de modification de surface des particules minérales. Le greffage d’alcoxysilanes a d’abord été entrepris sur des particules d’oxyde de cérium afin d’encourager la réaction de polymérisation à leur surface. Des observations par cryo-Microscopie Electronique à Transmission (cryo-MET) effectuées sur les latex hybrides obtenus par cette stratégie ont montré que le greffage d’alcoxysilanes ne permettait pas d’améliorer efficacement la compatibilité entre les phases inorganique et polymère. Enfin, des macro-agents RAFT amphiphatiques ont été employés comme agents comptabilisant réactifs afin de promouvoir la réaction de polymérisation à la surface de l’oxyde de cérium. Des oligomères RAFT ont été obtenus par des réactions de co- ou terpolymérisation en présence d’un agent de contrôle RAFT. Après caractérisation de l’adsorption des macro-agents RAFT à la surface de l’oxyde de cérium, les particules modifiées ont été utilisées dans des réactions de polymérisation en émulsion. Les observations des latex hybrides par cryo-MET ont confirmé l’efficacité de la méthode pour l’obtention de structures hybrides. Cette stratégie semble ainsi la plus prometteuse pour la synthèse de latex hybrides CeO2/PVDC pour des applications en tant que films barrières présentant une stabilité UV améliorée. / Food and pharmaceutical packages should nowadays fulfill a wide range of requirements : not only should they preserve the packed products from external polluting agents, but they must also be innocuous, more energy-efficient and disposable. Barrier polymers have enabled to meet these criteria, by offering alternatives to more energy-consuming and heavier materials like glass or metals, while maintaining a low permeability to water and/or oxygen. Among the large variety of barrier polymers, poly(vinylidene chloride) (PVDC) copolymers provide a more complete protection to external contaminants, due to their extremely low permeabilities towards water and oxygen. Nonetheless, PVDC films still suffer from limitations as far as their thermal and UV stabilities are concerned. This effect is even more pronounced in the case of films obtained from latexes, due to the presence of higher amounts of additives that could take part in the polymer degradation. Therefore, the synthesis of PVDC-based latexes for use as waterborne barrier films with improved thermal and UV stabilities are of great importance. PVDC-based composite latexes were first synthesized from epoxy-functionalized seed latexes in order to enhance the polymer thermal stability. Given that hydrogen chloride displays an indirect catalytic effect on the polymer degradation, epoxy groups were indeed expected to act as thermal stabilizers by scavenging the HCl released by the polymer under thermal stress. In a first step, epoxy-functionalized seed latexes were synthesized via the emulsion copolymerization of glycidyl methacrylate (GMA) and butyl methacrylate (BMA). In a second step, the seeded emulsion copolymerization of vinylidene chloride and methyl acrylate was carried out in the presence of poly(GMA-co-BMA) seed latexes. Thermogravimetric analyses carried out on the resulting composite samples evidenced the thermal stabilization provided by epoxy groups. The second part of the project focused on the synthesis of cerium oxide-based hybrid latexes so as to improve the stability of PVDC to UV radiation. Cerium oxide (CeO2) nanoparticles are indeed very attractive as UV-stabilizers due to their high absorption of radiation in the UV range and a low photocatalytic activity. However, due to the intrinsic incompatibility between inorganic and polymer phases, the synthesis of inorganic-organic hybrid latexes often requires a preliminary step of modification of the mineral particles surface. The grafting of alkoxysilanes onto nanoceria was first attempted in order to promote the polymerization reaction at the surface of the inorganic particles. Cryo-Transmission Electron Microscopy (cryo-TEM) observations of hybrid latexes obtained via this route showed that this strategy was unsuccessful at improving the compatibility between the inorganic and polymer phases. Amphiphatic macro-RAFT agents were finally considered as reactive compatibilizing agents to direct the polymerization towards the cerium oxide surface. RAFT oligomers were first obtained by co- or terpolymerization reactions in the presence of a RAFT controlling agent. After characterizing the adsorption of amphiphatic macro-RAFT agents at the surface of nanoceria, surface-modified cerium oxide particles were then engaged in reactions of emulsion polymerization reactions. In most cases, cryo-TEM observations carried out on the resulting latexes confirmed the efficiency of the amphiphatic macro-RAFT agent route for the synthesis of hybrid structures. Therefore this route appeared so far to be the most promising for the synthesis of CeO2/PVDC hybrid latexes for use as waterborne barrier films with improved UV-stability.

Les objectifs du travail présenté ici sont de comprendre les procédés de formulation des gouttelettes et des particules afin de faire des hybrides polymère-polymère de qualité en dispersions aqueuses et d’utiliser notre compréhension fondamentale de ces procédés pour : 1. Augmenter le taux de conversion de(s) monomère(s) autant que possible. 2. Comprendre l’impact de ces procédés sur les propriétés des films hybrides. Des cas particuliers ont été étudiés dans des conditions commercialement viables (taux de solide de 50% en masse) basés sur deux systèmes appelés alkyde-acryliques et polyuréthane-acrylique. La préparation des miniémulsions, la polymérisation en miniémulsion et la caractérisation des latex hybrides, l’incorporation chimique d’alkyde et de polyuréthane dans les monomères acryliques ont été étudiés en détails. Nous sommes parvenus à synthétiser et caractériser des latex hybrides avec de haut taux de solides (50% en masse) composés de particules de 100nm de diamètre utilisables dans des applications de revêtement et d’adhésifs / The objectives of work presented in this thesis are to understand droplet and particle formulation processes in order to make useful polymer-polymer hybrids in aqueous dispersions and use our fundamental understanding of these processes to: 1. Improve monomer conversion as much as possible. 2. Understand impact of these processes on hybrid film properties. Specific case studies of interest under commercially feasible conditions (i.e. solids content of 50wt %) were done based on two systems namely alkyd-acrylic and polyurethane-acrylic. Miniemulsification, miniemulsion polymerisation and characterisation of hybrid latex, chemical incorporation of alkyd and polyurethane to acrylic monomers were studied in detail. We have been able to successfully synthesise and characterise hybrid latex of about 100nm in particle diameter and high solids content (50wt %) to be used in coating and adhesive applications

Made available in DSpace on 2015-07-22T20:50:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-30 / Introdução: A alergia ao látex é responsável por inúmeras reações alérgicas em indivíduos sensibilizados. Objetivos: Avaliar a prevalência de sensibilização e alergia ao látex e a alimentos em crianças e adolescentes com mielomeningocele e identificar os possíveis fatores de risco a eles associados. Métodos: Participaram do estudo 55 crianças e adolescentes com diagnóstico prévio de mielomeningocele atendidos no ambulatório de Neurocirurgia do Hospital São Paulo, UNIFESP-EPM. Os pacientes foram avaliados através de questionário padrão, testes cutâneos de hipersensibilidade imediata para aeroalérgenos, látex total e alimentos e determinação de IgE sérica total e específica ao látex total e suas frações recombinates. Resultados: Encontramos taxas de 45% e 20% para sensibilização e alergia ao látex respectivamente, com 14,5% de sensibilização a alimentos, sem casos de alergia alimentar. Vinte e quatro (43,6%) eram atópicos e a média de idade do primeiro episódio de reação ao látex foi 44,5 meses, sendo reação cutânea a mais freqüente relatada (72,7%). A sensibilização alimentar ocorreu para os seguintes alimentos: batata, mamão, mandioca, jaca, manga, abacaxi, pêra, tomate, castanha portuguesa e abacate. Níveis séricos de IgE total superiores a 200 KU/l foram mais freqüentes no grupo de pacientes alérgicos e no de sensibilizados. A concordância pelo teste de kappa entre teste cutâneo para látex e IgE sérica específica para látex total foi forte e entre teste cutâneo para látex ou IgE sérica específica para látex total e as frações rHev b1, 3, 5, 6.01 e 6.02 foram moderada ou boa. As frações IgE séricas específica para látex detectada em mais de 50% dos pacientes alérgicos ao látex foram rHev b1, 3, 5, 6.01 e 6.02. Estatisticamente houve diferença entre o grupo de alérgicos e sensibilizados quando comparado ao de não sensibilizados para as seguintes variáveis: atopia, rinite atual, angioedema, número médio de cirurgias, pacientes com quatro ou mais cirurgias, uso de DVP, presença de pelo menos um teste cutâneo positivo para aeroalérgeno, presença de pelo menos um teste cutâneo para alimentos e IgE total maior que 200 KU/l. A análise multivariada revelou como significante: asma atual, angioedema, atopia e número de cirurgias submetidas. Conclusões: Nosso estudo documentou serem elevadas as prevalências de sensibilização e alergia ao látex. Apesar de freqüente a presença de anticorpos IgE específicos a alimentos, não se confirmou a presença da síndrome látex-fruta. O teste cutâneo com extrato de látex total padronizado se mostrou seguro e confiável para o diagnóstico de alergia ao látex. A análise comparativa entre os testes cutâneos de hipersensibilidade imediata e a determinação de IgE sérica específica ao látex total revelou concordância total entre eles. IgE sérica específica às frações rHev b1, 3, 5, 6.01 e 6.02 foram detectadas em mais de 50% das crianças e adolescentes com mielomeningocele alérgicos ao látex. O número de cirugias a que os pacientes foram submetidos determinou níveis mais elevados de IgE sérica específica, sobretudo de rHev b5 e 6.01. A história de asma atual, angioedema prévio, atopia e ter sido submetido a quatro ou mais cirurgias foram fatores independentes identificados para alergia ao látex. / Background: Latex allergy is responsible for numerous allergic reactions in sensitized individuals. Objectives: To evaluate the prevalence of sensitization and latex allergy and food in children and adolescents with myelomeningocele and to identify possible risk factors associated with them. Methods: The study included 55 children and adolescents previously diagnosed with myelomeningocele treated in the neurosurgery clinic of the Hospital São Paulo, UNIFESP-EPM. Patients were assessed using standard questionnaire, skin prick tests for aeroallergens, total latex, and food and determination of serum total and specific IgE to total latex and its recombinant fractions. Results: We found rates of 45% and 20% for sensitization and latex allergy, respectively, with 14.5% of sensitization to food, with no cases of food allergy. Twenty-four (43.6%) were atopic and the average age of first episode of reaction to latex was 44.5 months, with skin reaction the most frequent reported (72.7%). The food sensitization occurred for the following foods: potatoes, papaya, manioc, jackfruit, mango, pineapple, pear, tomato, avocado and chestnut. Serum total IgE greater than 200 KU/l were more frequent in patients allergic and sensitized. The agreement using the kappa test between latex skin test and specific IgE to total latex was strong and between skin test to latex or total latex specific IgE and fractions rHev b1, 3, 5, 6:01 and 6:02 were moderate or good. The fraction of specific IgE to latex detected in more than 50% of patients were rHev b1 (16/25 - 64%) followed by rHev b6.02 (14/25 - 56%). Statistically significant difference was found between the group of allergic and sensitive when compared to non-sensitized to the following variables: atopy, current rhinitis, angioedema, average number of surgeries, patients with four or more surgeries, use of valvule, presence of at least one test positive aeroallergen skin, presence of at least one skin test for food and total IgE greater than 200 KU/l. Multivariate analysis showed as significant: current asthma, angioedema, atopy and number of surgeries undergone. Conclusions: Our study documented high leves of sensitization and latex allergy. Despite the frequent presence of specific IgE antibodies to food, the presence of latex-fruit syndrome was not confirmed. The skin test with a standardized latex extract was safe and reliable for the diagnosis of latex allergy. The comparative analysis between the skin prick tests and determination of specific IgE to total latex showed total agreement between them. Specific IgE to fractions rHev b1, 3, 5, 6:01 and 6:02 were detected in more than 50% of children and adolescents with myelomeningocele allergic to latex. The number of surgeries for which patients underwent determined higher levels of specific IgE, especially rHev b5 and 6.01. The history of current asthma, prior angioedema, atopy and having undergone four or more surgeries were independent factors identified for latex allergy. / TEDE / BV UNIFESP: Teses e dissertações

Submitted by Maike Costa (maiksebas@gmail.com) on 2017-06-29T13:16:35Z No. of bitstreams: 1 arquivototal.pdf: 5298255 bytes, checksum: 86813ce5eab1b4b77b7cc4359031e69c (MD5) / Made available in DSpace on 2017-06-29T13:16:35Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 5298255 bytes, checksum: 86813ce5eab1b4b77b7cc4359031e69c (MD5) Previous issue date: 2017-03-24 / The subject of this work is the use of a lightweight markup language (Markdown) to write dissertations and theses according to the ABNT rules. This document shows the devel- opment of Limarka, a tool that makes possible to write dissertations and theses with a lightweight markup language, and a experiment involving ten students writing a proposal of dissertations or theses. The methodology used was unstructured interviews with qual- itative analysis. The objectives of this research are: implement a tool to make possible write dissertations and theses according to the ABNT rules and evaluate its usage. The main outcomes of this research comes from two sources: 1) knowledge acquired from the de- velopment of the application. They are: a dissertation or a thesis cannot be produced from a tool that uses the DocBook format as a intermediary format. The abnTeX communite makes available templates according to the ABNT rules. The use of a Latex templates based from abnTeX text. And the generation of Latex Code from Markdown texts. 2) knowledge acquired from the analysis of experiments. They are: For the configuration of the template, the use of PDF form instead of making YAML code. There are evidences that Markdown and Latex are equivalent, in capabilities, and users will find the usage of a lightweight markup language easier to learn and use than Latex. The main conclusion of this work is that it is possible to write a dissertation or a thesis using a lightweight markup and produce documents according to the ABNT rules. / O tema deste trabalho é a utilização de uma linguagem de marcação leve (Markdown) para elaboração de trabalhos de conclusão de curso em conformidade com as Normas da ABNT. Nele relata-se o desenvolvimento da ferramenta Limarka, que possibilitá a es- crita de TCC através de uma linguagem de marcação leve, e um experimental, com dez alunos elaborando propostas de TCCs nela. A metodologia empregada foi experimento com entrevistas semi-estruturadas e análise qualitativa. Os objetivos da pesquisa são: im- plementar uma ferramenta que possibilite a escrita de TCCs em conformidade com as Normas da ABNT e avaliar sua utilização. Os principais resultados da pesquisa tiveram duas fontes: 1) Conhecimentos resultantes do desenvolvimento da aplicação. São eles: um TCC não deve ser produzido por ferramentas que utilizem o formato DocBook como in- termediário; a comunidade abnTeX oferta uma ótima alternativa em Latex para produzir TCCs nacionais em conformidade com as Normas da ABNT; a utilização de um template baseado no modelo de TCC do abnTeX e a geração de códigos Latex a partir de Mark- down possibilita a geração de trabalhos em conformidade com as Normas da ABNT; 2) Conhecimentos provenientes da análise do experimento. São eles: para a configuração do template, a utilização de um formulário PDF, em vez de código YAML, torna o processo de configuração mais fácil; A solução com escrita em Markdown apresentam equivalência de expressividade ao Latex, pois permite a inserção de seus códigos; existem indícios de que os usuários acharão mais fácil aprender e utilizar Markdown do que Latex. A princi- pal conclusão do trabalho indica que é possível utilizar uma linguagem de marcação leve (Markdown) para escrita de TCCs nacionais em conformidade com as Normas da ABNT. E sua utilização deve ser incentivada pois é expressivamente equivalente a Latex, porém mais simples e fácil de ser utilizado.

Orientador: Neri Alves / Banca: Aldo Eloiza Job / Banca: Mariselma Ferreira / Banca: Angela Mitie Otta Kinoshita / Banca: Antonio José Felix de Carvalho / O Programa de Pós-Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi da Unesp / Resumo: Filmes auto-sustentáveis de polifluoreto de vinilideno (PVDF) e de polifluoreto de vinilideno com trifluoretileno (P(VDF-TrFE)) contendo amido de milho e/ou látex da borracha natural foram produzidos visando à obtenção de blendas biocompátiveis. Estas blendas foram produzidas pela técnica de prensagem a quente a qual não necessita fazer uso de solventes orgânicos para dissolver os polímeros sintéticos (PVDF e P(TrFE)). Tal processamento, além de não utilizar solventes tóxicos, possibilita a fabricação de filmes auto-sustentáveis com propriedades físicas e químicas apropriadas para aplicações como um material biocompatível. Os filmes de PVDF ou P(VDF-TrFE) com os polímeros naturais (amido e/ou látex de borracha natural) foram caracterizados através das técnicas de espectroscopia vibracional (absorção no infravermelho com transformada de Fourier (FTIR) e espalhamento Raman), análise termogravimétrico (TG), calorimetria exploratória diferencial (DSC), análise dinâmico-mecânica (DMA), microscopia ótica (MO), microscopia ótica (MO), microscopia eletrônica de varredura (MEV), difração de raios-X, densidade, índice de fluidez (MFI), dureza e condutividade térmica. Os resultados que os polímeros naturais estão bem dispersos na matriz de PVDF ou P(VDF-TrFE) em nível micrométrico e não interagem quimicamente com os polímeros sintéticos. As blendas apresentaram elevada estabilidade térmica, cujo módulo de elasticidade está na mesma ordem de grandeza do osso humano. Entretanto, observou-se que a adesão dos polímeros naturais é melhor para as blendas com P(VDF-TrFe). Adicionalmente, as estruturas cristalinas do PVDF-α e do P(VDF-TrFE) ferroelétrico são mantidos em todas as blendas. A densidade, a dureza, o índice de fluidez e os valores de condutividade térmica das blendas seguiram o que deve se esperar de misturas físicas... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Films of poly(vinylidene fluoride), PVDF, and poly(vinylidene fluoride - trifluoroethylene), P(VDF-TrFE), containing corn starch and latex of natural rubber were produced visioning to obtain biocompatible blends. These blends were produced by compressing/annealing, which discards the necessity of using organic solvents to dissolve the synthetic polymers (PVDF and P(VDF-TrFE)). This process, besides discarding the use of toxic solvents, allows obtaining self-standing films with suitable physical and chemical properties considering their application as biocompatible materials. The PVDF or P(VDF-TrFe) films with different percentage of the natural polymers (starch and/or latex of natural rubber) were characterized using thermogravimetry (TG), differential scanning calorimetry (DSC), and dynamicalmechanical analysis (DMA). Fourier transform infrared spectroscopy (FTIR) and Raman scattering, optic microscopy, scanning electric microscopy, scanning electric microscopy (SEM), X-ray diffraction, density, melt flow index, hardness, and thermal conductivity. The results showed that the natural polymers are well dispersed within the matrix of PVDF or P(VDF-TrFE) at micrometer level and do not interact chemically with the synthetic polymers. The blends present high thermal stability with elasticity modulus at the same order of magnitude of the bone. However, it was observed that the adhesion of the natural polymers is better for the blends of P(VDF-TrFE). Besides, the crystalline structures of the α-PVDF and ferroelectric P(VDF-TrFE) are kept in the blends. The density, hardness, melt flow index and thermal conductivity values of the blends followed what shoud be expected from physical mixtures. The tests of biocompatibility for these materials were carried out implanting the films at the subcutaneous region of rats the results showed histological characteristics favorable to the compatibility in vivo...(Complete abstract click electronic access below) / Doutor

Orientador: José Luiz Pinheiro Melges / Resumo: O bambu é uma planta renovável, perene, tropical e que apresenta uma série de vantagens, tais como: crescimento rápido, elevada resistência mecânica, grande versatilidade, beleza, e não necessita do replantio de colmos. Certamente, fica evidente que o bambu é um material de grande potencial, para diversos setores, sobretudo da construção civil, em que o mesmo vem sendo utilizado desde os tempos mais remotos. Nas estruturas de concreto, o bambu tem sido estudado como um elemento passível de resistir aos esforços de tração. Entretanto, como desvantagens, o bambu é um material orgânico e higroscópico. Após a concretagem, durante a cura do concreto, o bambu absorve água e, consequentemente, tem suas dimensões aumentadas. Com o concreto endurecido, o bambu começa a perder a água absorvida e se retrai, sofrendo uma redução de seu volume, o que diminui a eficiência da aderência entre os materiais. Outra desvantagem do bambu é a região do nó, cuja resistência à tração é muito inferior à da região internodal. O presente trabalho tem como principal objetivo avaliar o comportamento estrutural de vigas de concreto armado, sem e com reforço adicional de taliscas de bambu, por meio de ensaios de flexão. As taliscas de bambu utilizadas como reforço adicional à armadura são de dois tipos: com e sem reforços nas regiões nodais. Com o intuito de analisar a condição de aderência entre a talisca de bambu e o concreto, foram realizados ensaios de arrancamento. As taliscas foram elaboradas a parti... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Le latex de Carica papaya est un milieu riche en cystéine protéinases. Celles-ci ont été régulièrement utilisées en cosmétique ou pour l’attendrissement de la viande. Mais ces protéines ont aussi un intérêt pharmaceutique. En effet, le latex est bien connu pour posséder une activité antifongique mais aussi une activité anthelminthique. Ces effets sont régulièrement attribués aux cystéine protéinases qui se trouvent en concentration importante dans le latex. Malgré ces concentrations importantes en protéinases, d’autres protéines restent actives dans ce milieu. C’est le cas de la glutamine cyclase, qui a été extraite intacte de ce milieu et cristallisée. Sa structure nous a révélé une architecture particulière en ‘’&61538;-propeller‘’ à cinq pales avec double fermeture. Cette structure lui confère sa très grande stabilité. <p>Les industries pharmaceutiques sont aussi à la recherche de protéines très stables et résistantes aux protéinases endogènes. Nous avons donc entrepris l’étude du protéome de Carica papaya afin de mettre en évidence d’autres protéines minoritaires relativement stables pouvant conférer au latex son activité anthelminthique. Cette analyse a permis la mise en évidence de différentes protéines appartenant à diverses familles des « pathogenesis related protéins » (PR-proteins): une &61538;-1,3 glucosidase, une analogue à la barwin, une thaumatine et deux chitinases.<p>Nous nous sommes particulièrement intéressés à ces deux dernières au cours de cette thèse. Une caractérisation de ces deux protéines a permis de montrer que celles-ci étaient bien deux protéines distinctes, identifiées comme chitinases majeure et mineure selon leur abondance dans le latex. Elles sont relativement stables et résistantes à la protéolyse. Une analyse de la séquence de la chitinase majeure a montré que celle-ci était homologue à la chitinase issue de l’orge et une analyse de sa structure révèle la présence d’une grande concentration en prolines localisées principalement dans les neuf boucles de sa structure. Cela pourrait expliquer sa grande résistance vis à vis des cystéine protéinases.<p>La cristallisation de cette même chitinase en présence de N-acétyl-glucosamine comme additif, a conduit à une structure contenant trois molécules de GlcNac, deux dans le centre actif de notre protéine et une participant au réseau cristallin. Aucune structure de chitinase n’avait encore pu être obtenue en co-cristallisation avec un substrat. A partir des deux GlcNac observés dans le centre actif, nous avons reconstruit un complexe chitinase/(GlcNac)4. L’analyse de ce complexe a permis de mettre en évidence de nouvelles interactions entre (GlcNac)4 et les acides aminés du centre actif ainsi que de confirmer le mécanisme de la famille GH 19.<p> Des tests préliminaires sur nématodes ont finalement confirmé l’activité anthelminthique du latex et montré que la chitinase pouvait aussi être un bon nématocide<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

L'objectif de cette étude était le développement de particules colloïdales magnétiques possédants un cœur magnétisable et une écorce polymère, capables d'éliminer les métaux lourds, les colorants cationiques et les perturbateurs endocriniens. Ces adsorbants pourraient être séparés magnétiquement permettant ainsi de remplacer les techniques lourdes comme la centrifugation, la sédimentation, et la filtration. Les résultats des analyses, en termes de taille, de morphologie, de composition chimique, de propriétés magnétiques et de potentiel Zeta, confirme bien l'encapsulation de cœur magnétique par une écorce en polymère, et la fonctionnalisation de la surface de ces particules. Nous avons pris comme exemple l'élimination les métaux lourds (Cu2+, Pb2+, Zn2+ et HCrO4-), le bleu de méthylène ainsi le Bisphenol A, en solutions aqueuse. La fixation de divers polluants considérés se fait via l'adsorption à la surface des particules. Divers paramètres physico-chimiques influent le phénomène d'adsorption; l'effet de la quantité d'adsorbant magnétique élaboré, l'effet pH initial du milieu, l'effet du temps de contact, ainsi l'effet de la concentration initiale des polluants sont considérés. Cette étude a montré que l'adsorption est rapide et l'équilibre est atteint au bout de 30 min. Le processus d'adsorption est fortement dépendant du pH initial du milieu. La capacité d'adsorption de Latex des particules magnétiques élaborées vis-à-vis des éléments étudiés s'avère très satisfaisante comparé aux différents adsorbants magnétiques étudiés dans la littérature. La cinétique d'adsorption pour tous les systèmes étudiés pourrait être considérée comme pseudo-deuxième ordre et le processus d'adsorption de ces éléments par les particules magnétiques suit le modèle monocouche de Langmuir. Nous nous sommes intéressé à décontaminer les effluents industriels chargés en métaux lourds, issus des bains de traitement de l'Entreprise SOPAL. Les résultats obtenus nous ont permis de déduire que les particules magnétiques sont efficaces pour la décontamination. Les latex magnétiques pourraient être recommandés comme des adsorbants rapides, efficaces, et réutilisables pour l'élimination et la récupération des métaux lourds des eaux usées / The aim of this study was to prepare magnetic latex particles being magnetic core-polymer shell, able to remove heavy metals, cationic dyes and endocrine disrupting chemicals, by batch adsorption. These adsorbents were magnetically separated allows replacement of the heavy techniques such as centrifugation, sedimentation, and filtration by applying magnetic field.The results analysis in terms of colloidal and surface properties, transmission electron microscopy, hydrodynamic particle size, thermogravimetric analysis, and zeta-potential measurements, confirms the encapsulation of the magnetic core and the polymer shell, the surface functionalization of these particles, and the good colloidal stability. Heavy metals (Cu2+, Pb2+, Zn2+ and HCrO4-), methylene blue and Bisphenol A were taken as model of contaminants. Various physicochemical parameters influencing the adsorption phenomenon, which we have studied; the effect of adsorbents amount, the initial pH medium, the contact time, and the effect of the initial concentration of the pollutants. This study showed that the adsorption is fast and equilibrium is achieved within 30 min. The adsorption process is highly dependent on the initial pH. Adsorption capacities of the elaborated magnetic latex particles are very satisfactory when compared with different magnetic adsorbents reported in the literature. The adsorption kinetics for all the studied systems could be considered pseudo-second order model and the adsorption process of these elements by magnetic latex particles follows the Langmuir monolayer model. SOPAL wastewater sample load in heavy metals was analyzed by the prepared magnetic adsorbent. The results have enabled us to deduce that magnetic latex particles are effective for decontamination of real waste water. The prepared magnetic latex particles in this research can be recommended as fast, effective, and reusable for removal and recovery of metal ions from wastewater effluents

This diploma thesis has its purpose in creating such an editor of LATEX language, which would succeed in the competition of existing solutions. To offer users a basis typical for this type of editors and add functions that will make him a unique project. The progress went in a direction of transparent environment and completely trivial operating. Most of the functions are available through 1 click only. Predefined templates are displayed immediately including previews and it is possible to download them with all source codes. Some kinds of actions redraw the whole content of the page. In other cases, we used update panels for partially redraw the content or client javascript. Due to available archivation of .zip files we can even process more files at the same time. Program is designed in a way to be able to further continue developing it and even broaden his features.

Thesis (MScAgric)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Guayule (Parthenium argentatum Gray) is a semi-desert plant with the potential to become an established crop on arid land in South Africa. The plant produces latex, which can be processed into rubber that is useful in application where disease transmission needs to be limited, such as for surgical gloves and condoms. The poor germination and natural dormancy characteristics of the embryo and the seed coats of guayule seed, motivated germination experiments. Germination of seed treated with solutions of gibberellic acid, smoke water and smoke watergibberellic acid was determined. Furthermore, combinations of gibberellic acid, smoke water and sodium hypochlorite treatment solutions were applied to seed to determine the germination responses. Vegetative propagation of guayule by means of cuttings was also investigated to determine the rooting responses of cuttings with treatment solutions of indole butyric acid, naphthalene acetamide and naphthalene acetic acid. Rooting percentage, root length and root weight was determined for each treatment. Dryland field trial plantings were established at different areas in South Africa to determine the growth potential and biomass production of guayule cultivars under different environmental conditions. Stand count, height, canopy diameter and stem diameter was determined for the different cultivars and areas. Lastly, latex production of guayule cultivars established in trial plots at Elsenburg, Oudtshoorn and Graaff- Reinet was determined after one year of growth. Treatment solutions of an aqueous smoke extract (commonly referred to as smoke water) and gibberellic acid were evaluated to determine their effectiveness in stimulating germination of four guayule seed lines (AZlOl, AZ-3, N565 and 11591). The split-plot analyses of variance showed no significant interaction between cultivar and treatment factors (P = 0.71), but when the day factor was included interaction was highly significant (P < 0.0001). The applied treatment thus had an effect on the time required for the germination response. Investigations into optimum germination responses indicated that smoke water-gibberellic acid required the shortest number of days (6.3 days) for optimum germination to occur with cultivar AZ-3. Furthermore, gibberellic acid treatment resulted in the greatest germination with the four cultivars 11591, AZ- 3, AZI0l and N565, at 93.78%, 93.35%, 94.41% and 99.42% respectively. These results show that guayule seed can be stimulated to germinate by treatment with gibberellic acid and smoke water solutions. Specific concentrations of treatment solutions of gibberellic acid, smoke water and sodium hypochlorite, and combinations thereof were used to evaluate the germination response of guayule seed cultivar AZ-2. Combinations of treatment solutions did not result in significantly increased seed germination responses. Single treatment solutions of gibberellic acid and smoke water did not significantly enhance germination, but sodium hypochlorite however, significantly (p <0.0001) suppressed germination at the 1% Cl and 2% Cl concentrations with about 5% and 10% respectively when compared to the control. Therefore, the applied seed treatments did not effectively increase the germination of guayule cultivar AZ-2 seed. Specific concentrations of indole butyric acid, naphthalene acetamide and naphthalene acetic acid treatment solutions were applied to guayule cuttings of cultivar AZ-3 and rooting response was determined for rooting percentage, root length and root weight. Naphthalene acetic acid treatment rooted the highest percentage of cuttings (52.38%) at a concentration of 60 mgll. Indole butyric acid treatment produced the longest roots (147.83 mm) at a concentration of 120 mg/l. Naphthalene acetamide obtained the heaviest roots (1.8 g) at a concentration of 120 mgll. Treatment solutions of indole butyric acid, naphthalene acetamide and naphthalene acetic acid indicated specific concentrations for optimum effect to improve root formation (by 30%), root length (by 50 mm) and root weight (by 1.5 g) when compared to the controls. Guayule trial plots of IOx10 m, rows 1 m apart and 30 cm between plants, and each cultivar (10 plants per unit) placed at random and replicated 6 times, were established in different areas under different environmental conditions in South Africa. Plantings were evaluated as a dryland practice, though irrigation was supplied only for establishment. Growth (stand count, height, canopy diameter, stem diameter) and biomass (wet and dry weight) were recorded for (1) oneyear old plantings established in April 2001 at Elsenburg, Graaff-Reinet and Oudtshoorn, and (2) six-month old plantings established in October 2001 at Bethulie, Glen and Upington. Analysis of variance was done to determine mean growth and biomass for the different areas and cultivars. (1) There were significant interactions between the factors area and cultivar for stand count and height, while canopy diameter and stem diameter differences were significant only within factors. The greatest growth potential was produced by cultivars AZ-2 and AZ-3, and Oudtshoorn was the best area for growth potential and biomass production. (2) Interaction between area and cultivar was significant for plant height, but were not significant for stand count, canopy diameter and stem diameter. Cultivars produced similar results for biomass production, but were significantly different in the different areas of Bethulie, Glen and Upington. Growth potential and biomass production of guayule was influenced by the availability of water during the growth of the plant. Latex production of guayule cultivars (AZ-2, AZ-3, N565, 11591) established in trial plots at different areas (Elsenburg, Oudtshoorn, Graaff-Reinet) in South Africa was investigated. Branch samples of one-year old plantings were harvested in April 2002, dipped in 1% ascorbate, sealed in plastic bags and chilled during airfreight to the United States Department of Agriculture (USDA) - Agricultural Research Service (ARS) in Albany CA. Latex extraction and quantification was done and mean latex production and comparisons of latex production for the cultivars in each area were determined. The evaluation of latex production show generally similar results in the different areas. Cultivars generally do not differ significantly from each other in the amount of latex produced in each area. Environmental stress factors on latex production occur in especially Oudtshoorn and Graaff-Reinet where the temperatures are above 25°C and below 1DoC. Since guayule is a slow growing shrub, latex accumulation is also slow and takes 4-6 years to reach economic harvesting potential. Production results are therefore preliminary and require further evaluation after each year of growth to present a complete view of guayule latex production over time. Propagation investigations were successful in identifying techniques to germinate guayule seed and promote rooting of cuttings with specialized treatment solutions. Field establishment of guayule under South African environmental conditions has identified suitable areas and indicated cultivar performances in these areas. Evaluation of the latex production of field plantings has demonstrated the potential of guayule in these areas. Currently the path to guayule development is paved with a network of research activities that is strengthened through cooperation between research institutions and private sector companies that bridge the gap between academic research and market exhibition. / AFRIKAANSE OPSOMMING: geen opsomming