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Avaliação do emprego de técnicas de RMN e IV aliadas a métodos quimiométricos na investigação de autenticidade da droga vegetal comercial quebra-pedra
(Universidade Federal de São Carlos, 2009-02-06) Santos, Maiara da Silva; Ferreira, Antonio Gilberto; https://lattes.cnpq.br/3676462220401452; https://lattes.cnpq.br/3652794370160799
The importance of medicinal plants and their use in industrial purposes is increasing. Among the herbal drugs being commercialized there are "quebra-pedras". According to the the Brazilian Pharmacopoeia, the recognized officially species as medicinal plants having the attributed pharmacological properties to "quebra-pedras" are: Phyllanthus niruri and Phyllanthus tenellus. Other species of this genus, such as P. urinaria, P. amarus and P. caroliniensis, are also known. Usually, due to their morphoanatomyc similarities, the different species end up consumed without any discretion. In this context, this study evaluated the use of spectroscopic techniques, such as IR, 1H HR-MAS NMR and aqueous and ethanolic 1H NMR extracts, combined with chemometrics analyses, for inquiry commercial samples of "quebra-pedras". Through PCA and HCA analyses obtained from the data of these techniques, the taxonomic distinction among the studied Phyllanthus species (P. niruri, P. tenellus, P. amarus, P. urinary and P. caroliniensis) was successfully reached. Among the techniques evaluated, the 1H NMR extracts was the most appropriate for presenting greater reproducibility and have enabled, through analysis of their spectra, their additional experiments and comparisons with literature data, the identification of some primary metabolites (Lvaline, L-alanine, L-threonine, acid-4-aminebutanoic, D-sucrose, α- and β-Dglucose) in aqueous extracts and the compound phyllantin in the ethanolic extract. All seventeen built models using the KNN, SIMCA and PLS-DA methods had a good reliability. Working with a limited number of pattern samples (five, one of each specie) the classifications were different in some cases, but most of them showed that probably many of the commercial samples were not belonging to any of the studied Phyllanthus species, or to mixtures of them. However, the study of aqueous 1H NMR extracts, recorded to a higher number of patter plants, showed a great and a large variability data set, such as seasonal and regional factors, which are fundamental to building the models. The importance of the aromatic range in the aqueous extracts analyses was also examined. The signs in this range, although minority, are derived from secondary metabolites, and these are essential in the plants differentiation. In this context, considering the most representative classifications obtained from the aromatic range for the aqueous 1H NMR extracts, it is possible to concluded that 75% of analyzed commercial samples are P. tenellus, although in their labels were described as P. niruri. Also it was concluded that the evaluated spectroscopic techniques have a great potential in the investigation of complex matrices such as herbal drugs studied and the aqueous 1H NMR extracts has been the best results of them. It is important to mention that a representative data set is essential to the success of the employment of classification methods.
Dialogismo e tradição nas histórias em quadrinhos contemporâneas
(Universidade Federal de São Carlos, 2009-02-06) Figueira, Diego Aparecido Alves Gomes; Miotello, Valdemir; https://lattes.cnpq.br/9131819326282708; https://lattes.cnpq.br/8388127952061321
This study aims to examine some aesthetic trends from super-heroes comic books relate to the activity of collect them. The narratives of these magazines have long and continuous stories, without an end in perspective, interconnected with others magazines of the same publisher. The collector-reader appears crucial to examine the comic book production, since its plots usually are based on evidence and information about the characters mostly recovered of other older stories. We also consider relevant the presence of a media segment specialized in comics, also responsible for a form of criticism of comics that results in the idea of a canon and an aesthetic tradition to the genre. That specialized media became the space where rises and circulates a discourse about comics and a fan knowledge that dialogue with the discourse of the narratives. Based on Mikhail Bakhtin´s linguistics studies, we try to comprehend how that dialogue results in some sophisticated works, where the discourse about comics appears as metalanguage. One of that works is the Darwyn Cooke and Dave Stevens s graphic novel DC: The New Frontier, our principal object of analysis in this study.
Complexos de Cromo(III)-salen como catalisadores em reações de oxidação de sulfetos
(Universidade Federal de São Carlos, 2009-02-06) Aranha, Pedro Esteves; Dockal, Edward Ralph; https://lattes.cnpq.br/6461328124491559; https://lattes.cnpq.br/4014788760889813
Transition metal complexes participate in many chemical processes. The study of these complexes is very interesting because of the diversified chemistry and great utility. Transition metal complexes act as catalysts in various homogenous and heterogeneous systems. The catalytic activity of these complexes is due to the presence of only one active metallic site for the catalytic reaction. Thus this type of reaction can be advantageous due to the elevated selectivity of the metal center. The new catalysts were characterized by melting point, elemental microanalyses, infrared and visible-ultraviolet spectra, molar conductance, magnetic susceptibility and mass spectra. The catalytic reaction of phenyl methyl sulfide to phenyl methyl sulfoxide and/or phenyl methyl sulfone was carried out in flasks, under agitation and temperature control, the progress of the reaction was monitored by gas chromatography. The catalytic results for reactions of oxidation of sulfide presented yields above 48% with PhIO as oxidant. Twelve catalysts were tested where four of them oxidizes successfully phenyl methyl sulfide into phenyl methyl sulfoxide. Specially the complex [Cr(3,5-Isalen)(H2O)2]Cl that yields 98.2% in this reaction. Another complexes tested had good results in the first hours of reaction but led to formation of sulfone after some time of reaction. It was observed that complexes containing only electron donor substituents groups para to hydroxyl of phenolic ring and complexes with esteric substituents groups ortho and para to hydroxyl of phenolic ring presented more selectivity as catalyst for the reaction of oxidation of sulfide.