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Estratégias analíticas para a avaliação química de solos e liquens da Antártica marítima
(Universidade Federal de São Carlos, 2011-08-12) Guerra, Marcelo Braga Bueno; Pereira Filho, Edenir Rodrigues; https://lattes.cnpq.br/3394181280355442; https://lattes.cnpq.br/7474474218219859
The aim of this PhD thesis is the ample study of soil and lichen samples from Antarctica, collected in regions under strong anthropogenic impact. Surface soil samples were collected around several scientific stations: Brazilian (Comandante Ferraz), Argentinian (Esperanza), Chilean (Frei Montalva and Escudero), Chinese (Great Wall), Russian (Bellingshausen) and Uruguaian (Artigas). Control soil samples were also collected, for representing areas with low anthropic influence (far away from the local stations). Lichen samples (Usnea antarctica and Usnea aurantiacoatra) were collected near the Chilean and Russian stations, as well as in a control point far 0.5 km from the nearest station. X-ray Fluorescence was used as an analytical tool for the preliminary evaluation on metal contamination in the soil samples. Several extraction solutions (aqua regia, sequential extraction procedure, DTPA and CaCl2 solutions) were used to assess the amounts of metals in the soil samples. For Cd, Cr, Cu, Mn, Ni, Pb and Zn determination in the soil extracts, some analytical strategies were employed, such as fast sequential determination by FAAS in the conventional mode, as well as by using STAT-FAAS and TS-FF-AAS for evaluating Cd and Pb determination in DTPA soil extracts. The chemometric tools: HCA, PCA and PARAFAC were used for soil data treatment. Enrichment factors were calculated in order to infer about the degree of soil contamination. Soil samples collected around the stations diesel tanks were enriched with Cr and Pb. Soil samples from Esperanza station are the most contaminated ones, reaching 46, 18993 and 4823 mg kg-1 for Cd, Pb and Zn, respectively, for the strongest contaminated sites. The use of Flame-AAS and STAT-FAAS in the fast sequential mode appears as a good way that combines higher analytical throughput and better sensitivity (STAT-FAAS). Besides that, minimization of toxic wastes generation and xv economy of reagents are analytical advantages of this approach. The employment of chemometric tools are also an important strategy allowing the visualization of sample groupings and the variables related to them. A fast and simple method for pseudototal determination of metals in soil samples was developed. In this method, the samples were extracted with lower amount of aqua regia and in a reduced time (when compared with the official method) by using inexpensive centrifuge tubes. LAICP- MS was evaluated for direct determination of lead in the lichen samples and to access the distribution profile of this element in the organism structures. Lichen samples from heavily anthropogenic sites (near the stations) have the highest Pb concentrations ([Pb] = 8.71 mg kg-1 for the most contaminated sample and [Pb] = 1.12 mg kg-1 for the control point). LA-ICP-MS emerges as an adequate analytical method for direct Pb determination in lichen samples, notably when using carbon (naturally present in the samples) as internal standard. The medulla region of the lichen thalli is the main Pb bioacumulating lichen region.
Influência da adição de um fundente sintético no mecanismo de coloração final de revestimentos cerâmicos
(Universidade Federal de São Carlos, 2011-08-12) Santos, Geocris Rodrigues dos; Morelli, Márcio Raymundo; https://lattes.cnpq.br/0172837599844991; https://lattes.cnpq.br/2466041074193362
The presence of iron oxide in ceramic tile mass contributes to the reddish color firing of the products leading to a lower aggregate value, not to be regarded as a "noble" ceramic. However, the use of raw materials with low levels of iron oxides (Fe2O3) is economically unfeasible in Brazil, since most of the deposits have iron compounds as mineral component. Thus, the objective of this work was that of studying the interaction of the iron element in the final color mechanism of the ceramic tile mass. For this purpose, we have employed several compositions of stoneware tile mass making use of natural raw materials, and a synthetic flow. This flow is constituted of a vitreous phase of the silicates family obtained by fusion/solidification of oxides and carbonates. Such flow influences the color ceramic mass during the process of sinterization modifying the red color firing into whiteness. That occurs when added in compositions containing clays with high levels of iron oxides. Beyond the physical properties obtained from the different employed compositions, we have also used other characterization techniques in order to study the phenomenon, such as: X-ray photoelectron spectroscopy (XPS), Mössbauer spectroscopy, Xray diffraction (XRD), quantitative analysis of phases by Rietveld method and scanning electron microscopy (SEM). The results have shown that the synthetic flow acts as a modifying agent for color when incorporated with values above 33%wt. in the compositions and temperature at 1,100°C . The color firing modification occurs because the chemical composition of the synthetic flow assists to form new iron compounds, thus making the final color firing light. By using this mechanism in the ceramic substrates, the stoneware tiles can be manufactured using low cost clays with high levels of iron oxides. This method proved to be an economical as well as commercial strategy for the ceramic tile industries.
Extração de polissacarídeos do caroço de açaí (Euterpe oleracea)
(Universidade Federal de São Carlos, 2011-08-12) Freitas, Danieli Melo de; Pessoa, José Dalton Cruz; https://lattes.cnpq.br/4212703554284544; https://lattes.cnpq.br/5713377915953397
The development of the productive chain of agribusiness açaí depends on the proper disposal of by-products generated. The fruit is used currently only the mesocarp for human consumption, creating an environmental problem, since the core represents approximately 75-81% of the total weight of the fruit. The stone of açaí literature reports the presence of inulin, polyphenols and other carbohydrates. Among these inulin stands out for its low calorie and therefore applied in food production light in fat or low fat, as a substitute for fat and sugar. Despite being distributed worldwide, is not produced in Brazil and its imports makes it a product of high cost. Thus the design goal was to develop a method for extraction of inulin on a laboratory scale, aiming its industrial production. In the first stage of the project was undertaken to adapt the methodology for aqueous extraction of açai and the core of analytical methods for quantification of compounds. In the second stage of the project was carried out an experimental design to evaluate the effect of variables in the process of extracting the content of polysaccharides: temperature, particle size of the lump, mass / volume ratio and stirring speed of the mixture. In the third step, through the hydrolysis and HPLC analysis, was not found the polysaccharide inulin. By NMR analysis and infrared is proposed that this polysaccharide is a galactomannan. The content of the core polysaccharide, soluble in water, ranged 2-7%. The insoluble fraction of the core, obtained by extracting basic, representing 15% of the total mass.
Adaptações e respostas da modulação autonômica cardíaca frente a reabilitação hospitalar após cirurgia de revascularização do miocárdio: influência da função ventricular
(Universidade Federal de São Carlos, 2011-08-12) Mendes, Renata Gonçalves; Silva, Audrey Borghi; https://lattes.cnpq.br/4855616925791895; https://lattes.cnpq.br/9634590922242052
A tese constou de 3 estudos descritos a seguir. O estudo I, intitulado: Programa fisioterapêutico hospitalar de curto periodo composto por exercícios físicos supervisionados melhora a função autonômica cardíaca após cirurgia de revascularização do miocárdio - Estudo randomizado e controlado teve como objetivo investigar se um programa fisioterapeutico hospitalar melhora a funcao autonomica cardiaca (FAC) apos a cirurgia de revascularizacao do miocardio (CRM). 47 pacientes pos- CRM, foram randomizados para: grupo de exercicios (GE,n=24) ou cuidados usuais de fisioterapia (GCU, n=23). A avaliacao da FAC incluiu medidas da variabilidade da frequencia cardiaca (VFC). Na alta hospitalar, GE apresentou maiores valores dos indices rMSSD, AF,SD1, STD RR, SD2, DFA α1, DFA α2, entropia aproximada e media RR, p<0,05. Contrariamente, maiores valores da media FC, BF e BF/AF (balanco simpato-vagal) foram encontrados em GCU. Concluimos que um programa fisioterapeutico de exercicios fisicos, realizado durante a internacao pos-CRM, melhora a FAC. Na sequencia, o estudo II, intitulado: Função ventricular esquerda e adaptações autonômicas cardíacas após RC hospitalar em curto período - Estudo clínico prospectivo. objetivou avaliar as adaptacoes autonomicas cardiacas em pacientes com diferenca na funcao do ventriculo esquerdo (FVE) submetidos a CRM e a reabilitacao cardiaca (RC). Em 44 pacientes divididos em grupo FVE normal (FVEN >55%, n=23) e FVE reduzida (FVER= 35-54%,n=21) a FAC foi avaliada antes e apos a RC. Foi encontrada interacao grupo (FVEN vs FVER) vs tempo (efeito da RC) para dimensao de correlacao (CD) e SD2, com melhora significativamente maior para FVER. Pacientes com FVER apresentaram melhor adaptacao autonomica cardiaca frente a RC. Finalmente, o estudo III, intitulado: Respostas autonômicas cardíacas induzidas pelo exercício durante a RC hospitalar em pacientes submetidos a cirurgia cardíaca e com funções ventriculares diferentes. avaliou se os exercicios fisicos realizados na RC hospitalar podem evocar respostas autonomicas diferenciadas em pacientes pos-CRM e FVE diferentes. Nos mesmos pacientes do estudo II foram avaliados os indices da VFC em repouso e durante os exercicios metabolicos e deambulacao no primeiro dia pos-operatorio (PO1) e na alta hospitalar, respectivamente. No PO1 foram observadas diferencas (media RR e media da FC) entre o repouso e exercicio em ambos os grupos. Durante a deambulacao foram encontrados menores valores da VFC (STDRR, TINN, SD2, entropia Shannon e dimensao de correlacao) para FVER, assim como, para a variacao entre repouso e deambulacao para os indices STDRR, RR tri, TINN, SD2, rMSSD e dimensao de correlacao, P<0,05. Concluimos que em pacientes pos-CRM e com FVE normal, o exercicio fisico hospitalar desencadeou resposta autonomica cardiaca mais atenuada comparado a FVEN.