Lectins, multivalent carbohydrate-binding proteins of non-immune origin, have the unique ability to decode the information contained in complex carbohydrate structures of glycoproteins and glycolipids by stereo-specifically recognizing and binding to carbohydrates and carbohydrate linkages. The ubiquitous distribution of lectins in all forms of life and viruses along with their involvement in various biological processes such as cell-cell communication, host-pathogen interaction, cancer metastasis, embryogenesis, tissue development and mitogenic stimulation further emphasizes the importance of lectins in biological systems. Although not much is known about the endogenous roles of plant lectins, they constitute the most thoroughly studied class of lectins. On the basis of their subunit folds plant lectins have been divided in six major classes. They include jelly roll fold lectins (or legume lectins), hevein domain lectins (or cereal lectins), β-trefoil fold lectins, β-prism II fold lectins (or bulb lectins), β-prism I fold lectins and the most recently discovered lectin homologous to cyanovirin-N (http://www.cermav.cnrs.fr/lectines). Interestingly, of these, lectin subunits harbor an approximate three-fold symmetry in three cases and each subunit is believed to have evolved through successive gene duplication, fusion and divergent evolution. One of the major research activities in this laboratory involves structural studies on plant lectins. Decades of extensive studies in the laboratory have shed light on various structural and functional aspects of lectins such as variability in quaternary association, lectin-carbohydrate interactions, strategies for generating ligand specificity and multivalency. Furthermore, the β-prism I fold was first identified as a lectin fold in this laboratory through the X-ray analysis of the methyl-α-galactose complex of jacalin, one of the two lectins from the seeds of Artocarpus integrifolia. Subsequently, many other lectins with the same fold have been structurally characterized here and else where (http://www.cermav.cnrs.fr/lectines). They include mannose specific tetrameric artocarpin and dimeric banana lectin studied in this laboratory. Also investigated here is the structure of first dimeric β-prism II fold lectin, namely, garlic lectin. The subsequent work, carried out by the author, on the structure and dynamics of three-fold symmetric lectins form the subject matter of this thesis. Different web-servers available at NCBI and EXPASY web sites were used for sequence annotation studies. MRBAYES and MEGA were used for phylogenetic analysis. Molecular dynamics (MD) simulations were carried out using the simulation package GROMACS v.3.3.1. OPLS-AA/L and GLYCAM-06 force fields were used for proteins and carbohydrates respectively. Simulations were performed in explicit water system with TIP4P water model under NPT conditions with unit dielectric constant. The hanging drop method was used for crystallizing banana lectin and its complexes. Intensity data were collected on a MAR 345 image plate mounted on a Rigaku RU200 rotating-anode X-ray generator. The Oxford cryosystem was used when collecting data at low temperature. The data were processed using DENZO and SCALEPACK of HKL suite of programs. The structure factors from the processed data were calculated using TRUNCATE of CCP4 suite of programs. The molecular replacement program MOLREP was used for structure solution. Structure refinements were carried out using the CNS software package and REFMAC of CCP4. Model building was done using the molecular graphics program COOT. INSIGHT II, ALIGN, CONTACT, MUSTANG and SC of CCP4 were used for analysis of structural features. PROCHECK and web-server MOLPROBITY were used for the validation of the refined structures. The β-prism II fold lectins of known structure, all from monocots, invariably have three carbohydrate-binding sites in each subunit / domain. Until recently, β-prism I fold lectins of known structure were all from dicots and they exhibited one carbohydrate-binding site per subunit / domain. However, the recently determined structure of the β-prism I fold lectin from banana, a monocot, has two very similar carbohydrate-binding sites. This prompted a detailed analysis of all the sequences appropriate for the two lectin folds and which carry one or more relevant carbohydrate-binding motifs. The recent observation of a β-prism I fold lectin, griffithsin, with three binding sites in each domain further confirmed the need for such an analysis. The detailed sequence and phylogenetic analysis of all the β-prism I fold lectin or lectin-like sequences, available then, with particular attention to their carbohydrate-binding sites in them, in conjunction with the analysis of available three-dimensional structures demonstrate substantial diversity in the number of binding sites, unrelated to the taxonomical position of the plant source. However, the number of binding sites and the symmetry within the sequence exhibit reasonable correlation. The distribution of the two families of β-prism fold lectins among plants and the number of binding sites in them, appear to suggest that both of them arose through successive gene duplication, fusion and divergent evolution of the same primitive carbohydrate-binding motif involving a Greek key. Analysis with sequences in individual Greek keys as independent units lends further support to this conclusion. It would seem that the prepondence of three carbohydrate-binding sites per domain in monocot lectins, particularly those with the β-prism II fold, is related to the role of plant lectins in defence. Jacalin is the most thoroughly studied β-prism I fold lectin. A wealth of structural and thermodynamic data, mostly from this laboratory, led to a thorough characterization of carbohydrate-recognition in the case of jacalin. One aspect of jacalin that has not been investigated so far was its dynamics. The issue was addressed through reasonably long MD simulations, in explicit solvent system using all atom force field, of all the jacalin-carbohydrate complexes of known structure, models of unliganded molecules derived from the complexes and also models of relevant complexes where X-ray structures are not available. Results of the simulations and the available crystal structures involving jacalin permit delineation of the relatively rigid and flexible regions of the molecule and the dynamical variability of the hydrogen bonds involved in stabilizing the structure. Local flexibility appears to be related to solvent accessibility. Hydrogen bonds involving side chains and water bridges involving buried water molecules appear to be important in the stabilization of loop structures. The lectin-carbohydrate interactions observed in crystal structures, the average parameters pertaining to them derived from simulations, energetic contribution of the stacking residue estimated from quantum mechanical calculations and the scatter of the locations of carbohydrate and carbohydrate-binding residues, are consistent with the known thermodynamic parameters of jacalin-carbohydrate interactions. The simulations, along with X-ray results, provide a fuller picture of carbohydrate binding by jacalin than provided by crystallographic analysis alone. The simulations confirm that in the unliganded structures water molecules tend to occupy the positions occupied by carbohydrate oxygens in the lectin-carbohydrate complexes. Population distributions in simulations of the free lectin, the ligands and the complexes indicate a combination of conformational selection and induced fit. Mannose-specific β-prism I fold lectins, like lectins belonging to other plant families, exhibit interesting variability in their quaternary association. Mannose specific artocarpin and MornigaM are tetrameric, heltuba is octameric in the crystal structure and banana lectin and calsepa are dimeric. The modes of the dimerization in the last two are however, entirely different. This variability was explored through modelling and molecular dynamics simulations based on the known three-dimensional structures. This study, which combines computational approaches and results of X-ray analyses, provides valuable insights into the origin of the variability in quaternary association. MD simulations on individual subunits and the oligomers provide insights into the changes in the structure brought about in the protomers on oligomerization, including swapping of the N-terminal stretch in one instance. The regions which undergo changes also tend to exhibit dynamic flexibility during MD simulations. The internal symmetries of individual oligomers are substantially retained during the calculations. Simulations were also carried out on models using all possible oligomers employing the four different protomers. The unique dimerization pattern observed in calsepa could be traced to unique substitutions in a peptide stretch involved in dimerization. The impossibility of a specific mode of oligomerization involving a particular protomer is often expressed in terms of unacceptable steric contacts or dissociation of the oligomer during simulations. The calculations also lead to a rationale for the observation of a heltuba tetramer in solution although the lectin exists as an octamer in the crystal, in addition to providing insights into relations among evolution, oligomerization and ligand binding. The known crystal structures of banana lectin in its native and ligand bound forms revealed interesting features including the presence of two functional carbohydrate-binding sites per subunit. However, some confusion remained on the role of glycosidic linkage in carbohydrate-binding. The three crystal structures reported in this thesis provide information on details of the interactions of mannose and mannosylα-1,3-mannose with banana lectin and evidence for the binding of glucosyl-α-1,2glucose to the lectin. The known structures involving the lectin include a complex with glucosyl-β-1,3-glucose. Modelling studies on the three disaccharide complexes with the reducing end and the non-reducing end at the primary binding site are also presented here. The results of the X-ray and modelling studies show that the disaccharides with an α-1,3 linkage prefers to have the non-reducing end at the primary binding site while the reducing end is preferred at the site when the linkage is β-1,3 in mannose/glucose specific β-prism I fold lectins. In the corresponding galactose-specific lectins, however, α-1,3 linked disaccharides cannot bind the lectin with the non-reducing end at the primary binding site on account of steric clashes with an aromatic residue which occurs only when the lectin is galactose-specific. MD simulations based on the known structures involving banana lectin enrich the information on lectin-carbohydrate interactions obtained from crystal structures. They demonstrate that conformational selection as well as induced fit operate when carbohydrates bind to banana lectin. Snake gourd seed lectin (SGSL) isolated from Trichosanthes anguina is a glycosylated, galactose-specific, non-toxic lectin similar to type II ribosome inactivating proteins (RIPs) with a molecular weight of ~53kDa. It was established through preliminary X-ray studies that chain A with molecular weight of ~23kDa adopts the same fold as that of type I RIPs and the toxic chain of type II RIPs. Chain B with molecular weight ~32kDa has two β-trefoil fold domains and is responsible for the lectin activity of the protein. The two chains are connected with a disulphide bond. The sequence of the protein could not be determined using conventional methods despite extensive effort. It was derived from X-ray data at 2.4 Å resolution, which was used for structure analysis. The non-toxicity of SGSL appears to result from a combination of changes in the catalytic site in chain A and sugar-binding site in chain B. Detailed analysis of the sequences of type II RIPs of known structure and their homologues with unknown structure, provide valuable insights into the evolution of this class of proteins. It also indicates some variability in carbohydrate-binding sites, which appears to contribute to different levels of toxicity exhibited by lectins from various sources. In addition to the work on plant lectins, the author was also involved in studies on the crystal structures of the adipic acid complexes of L- and DL-Lysine. This investigation is presented in an appendix. A part of the work presented in the thesis has been reported in the following publications. Sharma, A., Thamotharan, S., Roy, S., & Vijayan, M. (2006). X-ray studies of crystalline complexes involving amino acids and peptides. XLIII. Adipic acid complexes of L- and DL-lysine. Acta Cryst, C62, o148-o152. Sharma, A., Chandran, D., Singh, D.D., & Vijayan, M. (2007). Multiplicity of carbohydrate-binding sites in beta-prism fold lectins: occurrence and possible evolutionary implications. J Biosci, 32, 1089-1110. Sharma, A., Sekar, K., & Vijayan, M. (2009). Structure, dynamics, and interactions of jacalin. Insights from molecular dynamics simulations examined in conjunction with results of X-ray studies. Proteins, 77, 760-777.

Materiais naturais são aplicados com restrições na joalheria por serem facilmente degradados e alterarem suas características estéticas em função das condições do ambiente. O porongo é um fruto que possui forte ligação simbólica com a cultura gaúcha por ser utilizado como recipiente (cuia) para tomar o chimarrão. Na fabricação de cuias são utilizados cerca de 50% do fruto gerando um grande volume de resíduos no processo, passível de ser aplicado em produtos. Desse modo, a presente pesquisa objetiva estudar e aplicar métodos de tratamento para o porongo, a fim de viabilizar a utilização desse material natural no design de joias, visando manter sua integridade física e química. Nesse sentido, primeiramente, foi realizada a caracterização do porongo por meio de técnicas como microscopia eletrônica de varredura, microscopia estereoscópica, análise termogravimétrica e microtomografia computadorizada (Micro-CT). Além disso, foram estudadas técnicas de tratamento que visam à durabilidade, além de melhorar as propriedades físicas e mecânicas de outros materiais naturais como, por exemplo, a madeira. A partir da hipótese de que técnicas semelhantes poderiam obter sucesso se aplicadas ao porongo, devido às similaridades na composição e estrutura de ambos os materiais, foram selecionados e adaptados métodos de tratamento para o porongo. Os resultados de Micro-CT indicam que o porongo possui 54% de volume poroso, sendo que a grande maioria dos poros são conectados,configurando permeabilidade. Com isso, optou-se por impregnação polimérica como método de tratamento e foram ensaiadas três concentrações de soluções contendo: metilmetacrilato (MMA), metanol (MeOH) e peróxido de benzoíla (PBO), em três condições de impregnação: 30 min de vácuo + 30min de imersão, 30 min de vácuo + 24h de imersão e imersão simples. Os melhores resultados foram obtidos com 30 min de vácuo + 24h de imersão. Estatisticamente, as diferentes proporções de MMA/MeOH não influenciam nos níveis de impregnação. As amostras foram submetidas a ensaios de absorção de água para avaliar a impregnação, indicando que aquelas que continham mais material polimerizado, por consequência, absorveram menos água. Por fim, o porongo foi novamente analisado por microtomografia e teve sua porosidade reduzida de 54% para aproximadamente 39% indicando um método potencialmente eficiente para o tratamento do porongo, visando a aplicação no design de biojoias. / Natural materials are restrictivly applied on jewelry because they are easily degraded and change their aesthetic characteristics due to ambient conditions. The gourd is a fruit that has a symbolic link with the “gaúcho” culture because it is widely used as a container (“cuia”) to drink the “chimarrão”. In the manufacture process of “cuias” it is utilized about 50% of the fruit, generating a large volume of wastes, which can be applied in products of higher earned value. Thus, this research aims to study and implement methods for the gourd improvement to enable the use of this natural material in jewelry design, through improvements of its physical and chemical integrity, in order to valorize artifacts and customs of the “gaúcho” culture. Accordingly, first the gourd characterization is performed through techniques such as scanning electron microscopy, stereoscopic microscopy, thermal analysis and computed microtomography. Moreover, in the present research will be studied treatment techniques that seeks to prolong durability and improve the physical-mechanical properties of other natural materials, such as polymer impregnation of wood. Probably, this technique can be successfully applied to gourd due to similarities in the composition and structure of both materials. Based on the theoretical approach developed, improvement methods to the gourd will be selected and adapted. Furthermore, it will be presented some preliminary results of impregnation. The present research also foresees the design biojewels collection using gourd treated. From the hypothesis that similar techniques could be applied to succeed gourd, due to similarities in the composition and structure of both materials, methods of improvement to the gourd were selected and adapted. The Micro-CT results indicate that the gourd has 54% of porous volume, whereas the great majority of the pores are connected by configuring permeability. Thus, it was decided by impregnation polymer as a method of improvement and were tested three concentrations of solutions containing: methyl methacrylate (MMA), methanol (MeOH) and benzoyl peroxide (PBO) in three conditions impregnation: 30 min vacuum + 30min immersion, 30min vacuum + 30 min 24h of immersion and immersion simple. The best results were obtained at 30 minutes + vacuum 24h of immersion. Statistically, different proportions of MMA/MeOH do not influence the levels of impregnation. The samples were tested for water absorption to evaluate the impregnation, indicating that those containing more polymerized material, therefore, absorbed less water. Finally, the gourd was again analyzed by microtomography and its porosity was reduced from 54% to approximately 39% indicating a method for improvement of potentially efficient gourd.

Mr Clarke used molecular genetic techniques to determine the origins of the sweet potato (kumara) and the bottle gourd in Oceania. Both are thought to have been introduced into Oceania by Polynesian voyagers who collected them from South America about 1,000 years ago (the word kumara is used by indigenous South Americans). Using new and improved DNA techniques, Mr Clarke analysed several hundred varieties of sweet potato and about 40 varieties of bottle gourd. The results are consistent with a pre-European introduction of these crops into Polynesia from South America, and have revealed something about their dispersal patterns within Polynesia, including New Zealand.

Mr Clarke used molecular genetic techniques to determine the origins of the sweet potato (kumara) and the bottle gourd in Oceania. Both are thought to have been introduced into Oceania by Polynesian voyagers who collected them from South America about 1,000 years ago (the word kumara is used by indigenous South Americans). Using new and improved DNA techniques, Mr Clarke analysed several hundred varieties of sweet potato and about 40 varieties of bottle gourd. The results are consistent with a pre-European introduction of these crops into Polynesia from South America, and have revealed something about their dispersal patterns within Polynesia, including New Zealand.

Mr Clarke used molecular genetic techniques to determine the origins of the sweet potato (kumara) and the bottle gourd in Oceania. Both are thought to have been introduced into Oceania by Polynesian voyagers who collected them from South America about 1,000 years ago (the word kumara is used by indigenous South Americans). Using new and improved DNA techniques, Mr Clarke analysed several hundred varieties of sweet potato and about 40 varieties of bottle gourd. The results are consistent with a pre-European introduction of these crops into Polynesia from South America, and have revealed something about their dispersal patterns within Polynesia, including New Zealand.

Made available in DSpace on 2015-04-11T13:55:46Z (GMT). No. of bitstreams: 1 Wanderleia Goncalves Ribeiro.pdf: 2671517 bytes, checksum: 05eb8fe34a413f7c6e4ed8a366450e51 (MD5) Previous issue date: 2012-07-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Studies on genetic diversity are an important tool for the use and conservation of plant genetic resources. One of the main reasons for the limited use of new germplasm is the lack of adequate documentation, characterization and evaluation of the material. Using this argument the objective of this study was to characterize morphological subsamples of snake gourd (Trichosanthes cucumerina L.), as well as develop a list of descriptors for the species and determine the genetic divergence among subsamples. The subsamples were collected in seven cities of Amazonas state Parintins (PIN I), Urucará (URU), Apuí (APU), Urucurituba (UTB), Itacoatiara (ITA), Manaus (MAO) and Iranduba (Ilha da Marchantaria - IMI), and one city of Pará state Terra Santa (TSA). Parintins was the only subsample that provided two subsamples (PIN II). The establishment of morphological characteristics that define the descriptors and the proposed methodology was made using lists for others cucurbits and adapted for the characteristics of snake gourd. Genetic variability was verified by multivariate analysis techniques expressing the multiples information in measures of similarity, thus the subsamples were grouped by the hierarchical method of average distances called UPGMA and graphic dispersion made by the method of principal coordinates analysis (PCO). The characterization of subsamples allowed establishing a list of 39 descriptors for Trichosanthes cucumerina referring to the flower, fruit and seed. The list was divided into characteristics (descriptors), classes, ranges and codes. The descriptors that exhibited the greatest variation were immature fruit color and shape of the ripe fruit, and the descriptors that not varied were number of flowers per raceme and shape of the seed. Analyze of genetic variability selected 14 descriptors that showed greater variation. The subsamples were more divergent APU and URU, and more similar were UTB and PIN I. The information from UPGMA and PCO showed the same results indicating no relationship between geographic distance and phenotypic similarity of snake gourd subsamples. The characterization and analysis of genetic variability indicated the existence of variability among the accessions evaluated of Trichosanthes cucumerina. / Os estudos sobre diversidade genética são uma importante ferramenta para o uso e conservação dos recursos genéticos vegetais. Uma das principais razões para a pouca utilização de novos germoplasmas é a falta de adequada documentação, caracterização e avaliação do material. Apoiado neste argumento, o objetivo deste estudo foi caracterizar morfologicamente subamostras de quiabo-de-metro (Trichosantes cucumerina L.), assim como elaborar uma lista de descritores morfológicos para a espécie e verificar a divergência genética entre as subamostras. As subamostras foram adquiridas nos municípios amazonenses de Parintins (PIN I), Urucará (URU), Apuí (APU), Urucurituba (UTB), Itacoatiara (ITA), Manaus (MAO) e Iranduba (Ilha da Marchantaria - IMI), e no município paraense de Terra Santa (TSA), sendo que apenas Parintins forneceu duas subamostras (PIN II). O estabelecimento das características morfológicas que definiram os descritores e da metodologia proposta foi feito a partir da consulta em listas para espécies pertencentes às cucurbitáceas e adaptadas de acordo com as características da planta de quiabo-de-metro. A variabilidade genética foi verificada através de técnicas de análises multivariadas, onde as informações múltiplas foram expressas em medidas de similaridade, a partir das quais as subamostras foram agrupados pelo método hierárquico das médias das distâncias, conhecido como UPGMA, e a dispersão gráfica feita pelo método da análise de coordenadas principais (PCO). Após a caracterização das subamostras, foi aperfeiçoada e estabelecida uma lista com 39 descritores para a espécie Trichosanthes cucumerina referentes à flor, fruto e semente. A lista foi dividida em características (descritores), classes, intervalos e códigos. Dos 39 descritores avaliados, os que apresentaram maior variação foram cor do fruto imaturo e formato do fruto maduro. Entre os descritores que não variaram ficaram número de flores por racimo e formato da semente. Para análise da variabilidade genética foram selecionados os 14 descritores que mais variaram. As subamostras mais divergentes foram APU e URU, e as mais similares foram UTB e PIN I. As informações geradas pelo UPGMA e PCO apresentaram os mesmos resultados, indicando que não há relação entre distância geográfica e similaridade fenotípica dos subamostras de quiabo-de-metro. A caracterização e a análise da variabilidade genética indicaram a existência de variabilidade entre as subamostras avaliadas de Trichosanthes cucumerina.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In recent years the research on new materials for application in construction had intensified in order to rationalize the manpower in the sector. Thereat, many studies are being conducted with the goal of developing composites for use in construction. The use of composites as wall panels is sustainable when the materials used are biodegradable. The objective of this research is produce and characterize polymeric composites using a castor oil polyurethane matrix reinforced with ramie, sisal and sponge gourd fibers. The composites were reinforced with unidirectional and randomly distributed fibers, with volume of 25%, 35%, 45% and 55%. The composites were produced compressed at room temperature, interleaving fiber and resin to secure the void reduction and adhesion of the fiber to the matrix. Through the tensile test the tensile strength, Young s modulus and maximum deformation were determined. The best results were obtained in composites reinforced with 45% unidirectional continuous sisal fibers. The composites reinforced with ramie fiber also showed excellent Young s modulus (23 GPa). Therefore, the study showed that fiber sisal, rami and sponge gourd reinforced castor oil polyurethane composites presented good properties for many uses in civil construction. / Nos últimos anos intensificou-se a busca por novos materiais para aplicação na construção civil, a fim de racionalizar a mão de obra no setor. Uma alternativa viável é a utilização da construção seca, que utiliza painéis de vedação montáveis com função de compartimentação dos ambientes. Com isso inúmeras pesquisas estão sendo realizadas para caracterização de compósitos para a construção civil. A aplicação de compósitos como painéis de vedação torna-se ainda mais sustentável quando os materiais utilizados são biodegradáveis. Assim, o objetivo deste trabalho é produzir e caracterizar compósitos poliméricos utilizando como matriz a resina poliuretana à base de óleo de mamona, reforçada com teores e distribuições variáveis de fibras de rami, sisal e bucha vegetal. Os compósitos foram reforçados com as fibras distribuídas unidirecionalmente e aleatoriamente, com teor de fibra de 25%, 35%, 45% e 55%, em volume. Os compósitos foram produzidos por compressão à temperatura ambiente, intercalando as camadas de fibras com a resina para redução dos vazios e garantir a adesão das fibras a matriz. A partir do ensaio de tração determinou-se a resistência à tração, módulo de elasticidade e a deformação máxima. As melhores propriedades apresentaram-se nos compósitos com 45% de reforço de fibra de sisal contínuo unidirecional. Os compósitos reforçados com fibra de rami também apresentaram módulo de elasticidade elevado (23 GPa). Portanto, pode-se concluir que os compósitos com resina poliuretana com reforço de sisal, rami e bucha vegetal apresentaram propriedades adequadas para usos diversos na construção civil. / Mestre em Engenharia Civil

Made available in DSpace on 2014-06-11T19:22:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-24Bitstream added on 2014-06-13T18:08:21Z : No. of bitstreams: 1 bastos_mab_me_ia.pdf: 4764593 bytes, checksum: 6b31254d53f07f52a1ccfe3293462dde (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esta dissertação trata da coleção de mates burilados, que constitui parte do acervo do Memorial da América Latina, no Pavilhão da Criatividade, em São Paulo, que estiveram expostos ao público, entre os anos de 2005 e 2009. Os estudos desenvolvidos sobre os mates burilados são para valorizar a cabaça como jóia ou livro circular, considerada patrimônio cultural peruano por representar a mais antiga tradição artística nesse suporte natural. O estudo do fruto cabaça, cuia ou mate, considera toda a sua potencialidade material e como suporte artístico tradicional e contemporâneo, nas mais diversas expressões de arte latinoamericanas. São abordados os fenômenos materiais e naturais deste fruto, buscando compreender a diversidade de suas espécies, as conexões com as civilizações e os desdobramentos de sua representação simbólica. A poética será o elo e elemento de fruição, nas relações entre as sociedades e suas tradições culturais. Desvelará e aproximará as mais variadas expressões artísticas, em diferentes períodos, revelando parte da história e meios de expressão de sociedades latinoamericanas. O estudo envolve a análise de três exposições de arte editadas na Argentina, Brasil e Peru, cujo foco é o fruto. Os artistas destacados são Mestre Didi, Walter Smetak, Catin Nardi, Gina Celeghini, Miguel Chikaoka, Marepe, Saint Clair Cemim, Os Gemeos e Victor Delfin. O mate é aqui apresentado como patrimônio cultural dos países do Cone Sul e Peru, por ser um fruto original, tradicional, popular, mestiço e, portanto, sua cultura é elemento de inclusão e integração dos povos latinoamericanos / The study is about “mate burilado” - the engraved or etched gourd collection from Peru, which is part of the patrimony of the Latin American Memorial exhibited in the Creativity Pavilion in São Paulo, from 2005 to 2009. The study about this art form serve to value the gourds as jewels or circular books as they are considered Peruvian cultural patrimony by representing the oldest artistic tradition using this natural support of art. The studies about gourds and mates, consider all the material potentiality of the fruit, as well as their use in various Latin American traditional and contemporary art expressions. In this study material and natural phenomena will be considered to comprehend the diversity of species, connections with the civilizations and the unfolding of their symbolic representation. The poetics of the gourds is the link and element for fruition in the relationship between the societies and their many cultural traditions. The piece of art is the tool used to unveil and approach the various art expressions throughout different periods of history and means of living of Brazilian and Latin American societies. Thus this essay involves the analysis of three art exhibitions in Argentine, Brazil and Peru, where the fruit is the main element. Some contemporary artists are made salient, namely Mestre Didi, Walter Smetak, Catin Nardi, Gina Celeghini, Miguel Chikaoka, Marepe, Saint Clair Cemim, Os Gemeos and Victor Delfin. The mate will be presented as part of the cultural patrimony of countries forming the south of Latin America and of Peru, because it is primitive, traditional, popular, “mestizo” and its culture is one of the elements, for inclusion and integration, of the Latin American people and their art / Este trabajo es el estudio de la colección de mates burilados, que constituye parte del acervo del Memorial de la América Latina, en el Pabellón de la Creatividad, en Sao Paulo, que fueron exhibidos al público entre los años de 2005 al 2009. Los estudios desarrollados sobre los mates burilados son para la valoración de la calabaza como una joya o un libro circular, considerada patrimonio cultural peruano por representar la más antigua tradición artística en ese soporte natural. El estudio del fruto seco calabaza o mate, considera toda su potencialidad material y como soporte artístico tradicional y contemporáneo en las más diversas expresiones de arte latinoamericanas. Son abordados los fenómenos materiales y naturales de ese fruto, buscando comprender la diversidad de sus especies, las conexiones con las civilizaciones y los desdoblamientos de su representación simbólica. La poética del fruto es el hilo de unión y elemento de fruición en las relaciones entre la sociedad y las diversas tradiciones culturales. Descubrirá y aproximará las más variadas expresiones artísticas en distintos periodos, revelando parte de la historia y medios de vida de las sociedades latinoamericanas. El estudio envuelve el análisis de tres exhibiciones de arte editadas en Argentina, Brasil y Perú, cuyo mote central es el fruto. Los artistas contemporáneos destacados son Mestre Didi, Walter Smetak, Catin Nardi, Gina Celeghini, Miguel Chikaoka, Marepe, Saint Clair Cemim, Os Gemeos e Victor Delfin. El mate es presentado como patrimonio cultural de los países del Cono Sur y del Perú, por ser un fruto original, tradicional, popular, mestizo y, por lo tanto su cultura es elemento de inclusión e integración de los pueblos latinoamericanos

nÃo hà / à crescente o interesse mundial pelo desenvolvimento de tecnologias chamadas âverdesâ que possibilitem o uso de produtos com menor impacto ao meio ambiente, assim como tambÃm se fortalecem as polÃticas de incentivo ao aproveitamento mÃximo e sustentÃvel dos recursos naturais. O principal objetivo desse estudo foi desenvolver nanobiocompÃsitos superparamagnÃticos para aplicaÃÃo como antenas ressoadoras dielÃtricas. Para tal, um plÃstico termorrÃgido biobaseado foi preparado utilizando o cardanol em alternativa aos fenÃis petroquÃmicos. Esse plÃstico termorrÃgido foi utilizado como matriz para o preparo de biocompÃsitos, utilizando 15% em massa de fibra de bucha bruta e tambÃm modificada por tratamento quÃmico (NaOH 5, 10 e 15% e NaClO 1%) como fase dispersa. Para o preparo dos nanobiocompÃsitos, alÃm da fibra de bucha, nanopartÃculas de magnetita, sintetizadas pelo mÃtodo da coprecipitaÃÃo, foram impregnadas no plÃstico termorrÃgido em diferentes teores de 1, 5 e 10% em massa. TÃcnicas de Termogravimetria (TG), Calorimetria exploratÃria diferencial (DSC), AnÃlise dinÃmico-mecÃnica (DMA), Microscopia eletrÃnica de varredura (MEV), Microscopia Ãptica, Microscopia eletrÃnica de transmissÃo (MET), DifraÃÃo de raios X (DRX), Espectroscopia no infravermelho com transformada de Fourier (FTIR), Espectroscopia MÃssbauer, Ensaios de resistÃncia à traÃÃo, Medidas dielÃtricas, Magnetometria de amostra vibrante (VSM) e BiodegradaÃÃo em solo simulado foram utilizadas para caracterizaÃÃo. Os resultados mostraram que o tratamento alcalino melhorou a estabilidade tÃrmica e o Ãndice de cristalinidade da fibra de bucha. O agente reticulador utilizado (DETA) mostrou-se eficiente, possibilitando a cura completa dos materiais. Os biocompÃsitos com fibra tratada apresentaram maior estabilidade tÃrmica, resistÃncia à traÃÃo superior e melhor Ãndice de biodegradaÃÃo em relaÃÃo ao biocompÃsito com fibra natural. A magnetita sintetizada exibiu tamanho nanomÃtrico, alÃm de alta pureza, alta cristalinidade e carÃter superparamagnÃtico. Todos os nanobiocompÃsitos exibiram superparamagnetismo e mostraram excelente estabilidade tÃrmica, boas taxas de biodegradaÃÃo e melhor resistÃncia mecÃnica para o material com 10% de magnetita. Todas as antenas ressoadoras dielÃtricas preparadas apresentaram perda de retorno satisfatÃria e, portanto, adequaÃÃo para fins comerciais e tecnolÃgicos, com maior potencial para atuaÃÃo em banda larga. / There is a growing global interest for the development of green technologies that allow the use of products with less damage to environment, as well as for maximum and sustainable use of natural resources. The main aim of this study was to develop superparamagnetic nanobiocomposites for application as dielectric resonator antennas. For this purpose, a biobased thermoset plastic was prepared by using cardanol as an alternative to petrochemical phenol. This thermoset plastic was used as a polymer matrix and biocomposites were prepared by using 15 wt% of untreated and modified sponge gourd fibers by chemical treatment (NaOH 5, 10, and 15 wt% and NaClO 1 wt%) as dispersed phase. For the nanobiocomposites preparation, besides the sponge gourd fibers insertion, the thermoset plastic were also impregnated with magnetite nanoparticles in different contents (1, 5, and 10 wt%). Techniques of Thermogravimetry (TG), Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), Optical Microscopy, Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), MÃssbauer Spectroscopy, Tensile testing, Dielectric measurements, Vibrating Sample Magnetometry (VSM) and Biodegradation in simulated soil were performed for characterization. The results showed that alkaline treatment improved the thermal stability and the crystallinity index of the sponge gourd fiber. The crosslinking agent used (Diethylenetriamine) was efficient and enabled complete cure for all materials. The biocomposites reinforced by treated fiber showed better thermal stability, superior performance in Tensile testing and greater biodegradation rates, when compared to the biocomposite reinforced by raw fiber. The magnetite particles exhibited nanometric size, high purity and crystallinity, and superparamagnetic character. All nanobiocomposites showed superparamagnetic behavior, excellent thermal stability, good biodegradation rates, and better mechanical strength for the material with magnetite 10 wt%. All dielectric resonators antennas exhibited satisfactory return loss and suitability for commercial and technological applications, especially for performance in broadband.

SILVA, André Leandro. Nanobiocompósitos superparamagnéticos para aplicação como antenas ressoadoras dielétricas. 2014. 126 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Departamento de Quimica Orgânica e Inorgânica, Programa de Pós-Graduação e Biotecnologia, Renorbio - Rede Nordeste de Biotecnologia, Fortaleza-CE, 2014. / Submitted by demia Maia (demiamlm@gmail.com) on 2016-05-20T13:09:52Z No. of bitstreams: 1 2014_tese_alsilva.pdf: 6480806 bytes, checksum: 946e32810e24c5137dfbba52bfd30bb8 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-05-20T13:10:43Z (GMT) No. of bitstreams: 1 2014_tese_alsilva.pdf: 6480806 bytes, checksum: 946e32810e24c5137dfbba52bfd30bb8 (MD5) / Made available in DSpace on 2016-05-20T13:10:43Z (GMT). No. of bitstreams: 1 2014_tese_alsilva.pdf: 6480806 bytes, checksum: 946e32810e24c5137dfbba52bfd30bb8 (MD5) Previous issue date: 2014 / There is a growing global interest for the development of green technologies that allow the use of products with less damage to environment, as well as for maximum and sustainable use of natural resources. The main aim of this study was to develop superparamagnetic nanobiocomposites for application as dielectric resonator antennas. For this purpose, a biobased thermoset plastic was prepared by using cardanol as an alternative to petrochemical phenol. This thermoset plastic was used as a polymer matrix and biocomposites were prepared by using 15 wt% of untreated and modified sponge gourd fibers by chemical treatment (NaOH 5, 10, and 15 wt% and NaClO 1 wt%) as dispersed phase. For the nanobiocomposites preparation, besides the sponge gourd fibers insertion, the thermoset plastic were also impregnated with magnetite nanoparticles in different contents (1, 5, and 10 wt%). Techniques of Thermogravimetry (TG), Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), Optical Microscopy, Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Mössbauer Spectroscopy, Tensile testing, Dielectric measurements, Vibrating Sample Magnetometry (VSM) and Biodegradation in simulated soil were performed for characterization. The results showed that alkaline treatment improved the thermal stability and the crystallinity index of the sponge gourd fiber. The crosslinking agent used (Diethylenetriamine) was efficient and enabled complete cure for all materials. The biocomposites reinforced by treated fiber showed better thermal stability, superior performance in Tensile testing and greater biodegradation rates, when compared to the biocomposite reinforced by raw fiber. The magnetite particles exhibited nanometric size, high purity and crystallinity, and superparamagnetic character. All nanobiocomposites showed superparamagnetic behavior, excellent thermal stability, good biodegradation rates, and better mechanical strength for the material with magnetite 10 wt%. All dielectric resonators antennas exhibited satisfactory return loss and suitability for commercial and technological applications, especially for performance in broadband. / É crescente o interesse mundial pelo desenvolvimento de tecnologias chamadas “verdes” que possibilitem o uso de produtos com menor impacto ao meio ambiente, assim como também se fortalecem as políticas de incentivo ao aproveitamento máximo e sustentável dos recursos naturais. O principal objetivo desse estudo foi desenvolver nanobiocompósitos superparamagnéticos para aplicação como antenas ressoadoras dielétricas. Para tal, um plástico termorrígido biobaseado foi preparado utilizando o cardanol em alternativa aos fenóis petroquímicos. Esse plástico termorrígido foi utilizado como matriz para o preparo de biocompósitos, utilizando 15% em massa de fibra de bucha bruta e também modificada por tratamento químico (NaOH 5, 10 e 15% e NaClO 1%) como fase dispersa. Para o preparo dos nanobiocompósitos, além da fibra de bucha, nanopartículas de magnetita, sintetizadas pelo método da coprecipitação, foram impregnadas no plástico termorrígido em diferentes teores de 1, 5 e 10% em massa. Técnicas de Termogravimetria (TG), Calorimetria exploratória diferencial (DSC), Análise dinâmico-mecânica (DMA), Microscopia eletrônica de varredura (MEV), Microscopia óptica, Microscopia eletrônica de transmissão (MET), Difração de raios X (DRX), Espectroscopia no infravermelho com transformada de Fourier (FTIR), Espectroscopia Mössbauer, Ensaios de resistência à tração, Medidas dielétricas, Magnetometria de amostra vibrante (VSM) e Biodegradação em solo simulado foram utilizadas para caracterização. Os resultados mostraram que o tratamento alcalino melhorou a estabilidade térmica e o índice de cristalinidade da fibra de bucha. O agente reticulador utilizado (DETA) mostrou-se eficiente, possibilitando a cura completa dos materiais. Os biocompósitos com fibra tratada apresentaram maior estabilidade térmica, resistência à tração superior e melhor índice de biodegradação em relação ao biocompósito com fibra natural. A magnetita sintetizada exibiu tamanho nanométrico, além de alta pureza, alta cristalinidade e caráter superparamagnético. Todos os nanobiocompósitos exibiram superparamagnetismo e mostraram excelente estabilidade térmica, boas taxas de biodegradação e melhor resistência mecânica para o material com 10% de magnetita. Todas as antenas ressoadoras dielétricas preparadas apresentaram perda de retorno satisfatória e, portanto, adequação para fins comerciais e tecnológicos, com maior potencial para atuação em banda larga.