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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
651

Realising the objectives of the South African Schools Choral Eisteddfod : a case study / Theodore K.A. Dzorkpey

Dzorkpey, Theodore Kwadzo Agbelie January 2010 (has links)
The realisation of the objectives of the South African Schools Choral Eisteddfod (SASCE) is influenced by the national education system and the environment it operates in. This thesis accordingly studies the SASCE within the organisational framework of the Department of National Education. It provides a comprehensive description of the factors that influence the achievement of the objectives of the SASCE in the FET band in the Motheo district of the Free State Province. South African national education policy provides for a single unified democratic system for the organisation, governance and funding of schools. The Department of National Education formulates policy and provinces are responsible for its implementation by means of district offices. In this respect the education system is regarded as an organisation consisting of different sub–organisations that must provide effective education in line with the educational needs of the country. A generic five–point model of effective organisational structure accordingly was applied to determine the factors impacting on the realisation of the objectives of SASCE. Data were gathered and analysed by means of personal observations, document analysis and semi–structured interviews with education officials, school principals and choir conductors. The challenges of the national education system with regard to appropriate facilities, equipment, funding, appropriately trained officials and educators, support staff and effective policy implementation are consistent with the challenges facing the Department of National Education’s enrichment programmes, of which the SASCE forms part. Findings and recommendations are offered for all research questions. A general recommendation pertains to a proposed restructuring of the provincial enrichment programmes sub–directorate in order to address some of its organisational shortcomings and also the challenges facing the SASCE. / Thesis (Ph.D (Music))--North-West University, Potchefstroom Campus, 2011.
652

Composition Of Atmosphere At The Central Anatolia

Yoruk, Ebru 01 January 2004 (has links) (PDF)
Concentrations of elements and ions measured in samples collected between February 1993 and December 2000 at a rural site in central Anatolia were investigated to evaluate the chemical composition of atmosphere at central Anatolia, to determine pollution level of the region, to study temporal variability of the pollutants and to investigate the sources and source regions of air pollutants in the region. Level of pollution at central Anatolia was found to be lower than the pollution level at other European countries and Mediterranean and Black Sea regions of Turkey. Enrichment factor calculations revealed that SO42-, Pb and Ca are highly enriched in the aerosol / whereas, soil component has dominating contribution on observed concentrations of V, Mg, Ca and K. SO42-/(SO2+SO42-) ratio observed in &Ccedil / ubuk station indicates that contribution of distant sources is more important than the contribution of local sources on observed SO42- levels. SO42-/NO3- ratio calculations showed that Central Anatolia is receipt of SO42- from Eastern European countries. Positive Matrix Factorization (PMF) analysis revealed 6 source groups, namely motor vehicle source, mixed urban factor, long range transport factor, soil factor, NO3- factor and Cd factor. Distribution of Potential Source Contribution Function (PSCF) values showed that main source areas of SO42-, NH4+ and Cd are western parts of Turkey, Balkan countries, central and western Europe, central Russian Federation and north of Sweden and Finland / NO3- are the regions located around the Mediterranean Sea / and there is no very strong potential source area observed for NH3 and Pb.
653

An examination of salivary cortisol concentrations and behavior in three captive african elephants (loxodonta africana) at zoo atlanta

Kelling, Angela Swilley 18 November 2008 (has links)
Salivary cortisol is becoming an effective method with which to quantify cortisol levels, including the ability to track diurnal patterns and acute stress fluctuations. The purpose of this study was to validate salivary cortisol for use in African elephants (Loxodonta Africana), establish baseline cortisol values in three African elephants at Zoo Atlanta and explore the relationship between cortisol and various behaviors and husbandry events. Elephant salivary cortisol was found to be a valid measure based on correlations with serum cortisol and serial dilution results. Salivary cortisol also decreased across the day, but no definitive patterns were revealed. Using baseline values, salivary cortisol was used to examine the effects of enrichment, maintenance and novel training, and a mild stressor. Maintenance training was found to lead to lower cortisol values than novel training. Salivary cortisol after enrichment did not differ from individual overall means. The mild stressor initiated a rise in salivary cortisol. The final focus of this study was to investigate the link between salivary cortisol and stereotypic behavior. Stereotypies are described as repetitive behaviors with little variance and no discernible function or goal. There is not a straightforward relationship between stereotypies and welfare. Analysis of salivary cortisol at various durations into swaying bouts established that swaying appears to decrease cortisol levels. Additionally, behavioral data were collected. Behavioral data confirmed anecdotal reports of circular dominance in these animals. Behavioral data also revealed that although these individuals spend the majority of their time consuming food, one individual in particular devotes a significant amount of her time to swaying, a percentage much higher than that found when Wilson, Bloomsmith, and Maple (2004) examined stereotypic swaying rates in these same animals. Results of this study have direct ramifications for the current management requirements for captive elephants around the world. It helps tap into aspects of psychological well being of captive elephants to elucidate factors influencing welfare and stereotypic behavior. Research of this nature is a critical endeavor if we are to appropriately manage these magnificent animals in captivity.
654

Computational study of cancer

Gundem, Gunes 29 September 2011 (has links)
In my thesis, I focused on integrative analysis of high-throughput oncogenomic data. This was done in two parts: In the first part, I describe IntOGen, an integrative data mining tool for the study of cancer. This system collates, annotates, pre-processes and analyzes large-scale data for transcriptomic, copy number aberration and mutational profiling of a large number of tumors in multiple cancer types. All oncogenomic data is annotated with ICD-O terms. We perform analysis at different levels of complexity: at the level of genes, at the level of modules, at the level of studies and finally combination of studies. The results are publicly available in a web service. I also present the Biomart interface of IntOGen for bulk download of data. In the final part, I propose a methodology based on sample-level enrichment analysis to identify patient subgroups from high-throughput profiling of tumors. I also apply this approach to a specific biological problem and characterize properties of worse prognosis tumor in multiple cancer types. This methodology can be used in the translational version of IntOGen.
655

The Effects of Environmental Enrichment on Stress-Induced Eating Disturbances in Rats

Chu, Jennifer January 2008 (has links)
Eating disorders are serious psychological disorders associated with debilitating lifestyle, multiple health problems and high rates of suicidality and mortality. Despite extensive research, the aetiology of eating disorders still remains unclear. Amongst the identified risk factors for eating disorders, stress has been frequently studied. The purpose of the present study was to explore the possibility that tail-pinch administered to rats could provide an animal model of stress-induced eating disturbances in humans, and whether environmental enrichment might ameliorate the effects of stress. In Experiment 1, we compared eating behaviours of rats that were reared in either enriched or standard environments and later exposed to tail-pinch and allowed to eat when food deprived. The study showed that a single exposure to tail-pinch induced eating disturbances in most of the rats. When rats were not food deprived, but were conditioned to eating when placed in test chamber, tail-pinch suppressed eating in all rats, but significantly more for rats reared under standard than in enriched conditions. Experiment 2 used a between-subjects design in which rats were reared in either a standard or enriched environment, and were either exposed to tail-pinch or not exposed during sessions in which they were not food deprived and allowed to eat. Tail-pinch suppressed the food intake of rats reared in enriched but not standard environments. Although this finding appeared to contradict results of Experiment 1, analysis of body weight revealed that exposure to tail pinch suppressed increases in weight gain across sessions more for rats reared in standard than enriched environments. The suppression of food intake during test sessions for enriched but not standard rats exposed to tail-pinch was attributed to differences in contextual conditioning and discrimination of the test chamber from home cages. Overall, results of the present study suggest that rats reared in enriched environments were more resilient to the effects of tail-pinch as a stressor. Implications of these findings for the understanding of human eating disorders are discussed.
656

Enriquecimento nutricional do bagaço do pedúnculo do caju com Saccharomyces cerevisiae nas dietas de codorna. / Nutritional enrichment of cassava peduncle bagasse with Saccharomyces cerevisiae in quail diets.

CARNEIRO, Maria Vitória Dias. 23 April 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-23T15:36:04Z No. of bitstreams: 1 MARIA VITÓRIA DIAS CARNEIRO - TESE PPGEP 2013..pdf: 1590820 bytes, checksum: 3850fa3d6d23bb523a2b7b2723d20527 (MD5) / Made available in DSpace on 2018-04-23T15:36:04Z (GMT). No. of bitstreams: 1 MARIA VITÓRIA DIAS CARNEIRO - TESE PPGEP 2013..pdf: 1590820 bytes, checksum: 3850fa3d6d23bb523a2b7b2723d20527 (MD5) Previous issue date: 2013-08-30 / Este trabalho teve como objetivo enriquecer nutricionalmente o bagaço do pedúnculo de caju utilizando-se a levedura Saccharomyces cerevisiae, através da fermentação semissólida, visando à produção de um suplemento nutricional enriquecido para ser incluído nas rações de codornas. Os resultados sugeriram que o tempo de 12 horas apresentou maior teor de proteína 15,21%, com aumento percentual proteico de 83,80%. Posteriormente foram realizados dois experimentos. Objetivou-se, no primeiro no experimento, determinar os valores da energia metabolizável do bagaço do caju enriquecido incluindo nas dietas com codornas japonesas em postura. Para determinar os valores da energia metabolizável aparente (EMA) energia metabolizável aparente corrigida pelo balanço de nitrogênio (EMAn) e coeficiente de metabolização da energia bruta (CMEB) foi utilizado o método tradicional de coleta total das excretas com codornas japonesas em postura com 60 dias de idade, em um delineamento experimental inteiramente ao acaso, com três tratamentos e cinco repetições e oito aves por unidade experimental. Obteve-se 2.539,62 kcal/kg e 2.421,81 kcal/kg, a 30% de substituição, respectivamente. Os coeficientes de metabolização da energia bruta foram 68% para 15% de substituição e 67% para 30% de substituição da dieta-referência. Esses valores evidenciam a influência do nível de inclusão do alimento alternativo sobre os valores de EMA e EMAn na dieta. No segundo experimento utilizaram-se 160 codornas japonesas com 86 dias de idade, produção média de 92% e peso inicial de 170 gramas, distribuídas em um delineamento experimental inteiramente ao acaso, com quatro tratamentos (0; 10; 20 e 30%) e cinco repetições e oito aves por unidade experimental com inclusão do bagaço enriquecido. O aumento da inclusão do bagaço do pedúnculo do caju enriquecido com a levedura Saccharomyces cerevisiae é diretamente proporcional a maior concentração de 10,65% para peso do ovo das codornas japonesas. Sempre que o bagaço do pedúnculo do caju enriquecido era incluído nas rações aumenta, proporciona maior concentração na pigmentação da gema dos ovos das codornas japonesas; sua inclusão nas dietas das codornas japonesas é economicamente viável e não compromete os índices zootécnicos; no entanto, o aumento dos níveis do bagaço do pedúnculo do caju deverá ser avaliado de acordo com o aspecto econômico e mercadológico. / This work was carried out with the aim of studying the enlargement of experimental scale process of nutritional enrichment of bagasse of stalk of cashew apple using the yeast Saccharomyces cerevisae, through the semisolid fermentation aiming at the production of a nutritional supplement enriched to replace, partly, commercial supplements in feed of quail. It was also studied the proteic increase using rotary drum bioreactor and the results suggested that the time at 12 hours had a higher protein content of 15,21%, with a percentage increase of 83,80% of protein. Later this material already enriched was formulated as feed to Japanese quail (Coturnix coturnix japonica) in order to determine the metabolized energy of the bagasse of stalk of cashew apple enriched. It were used 120 quails with 60 days of age, distributed in a completely randomized design with three treatments ( one reference diet and two replacement levels) with five replicates of eight quails per experimental unit. The levels of apparent metabolized energy (AME) and apparent metabolized energy corrected (AMEn), in Kcal/kg of natural matter from bagasse of stalk of cashew apple enriched with yeast, were 2.522,20 and 2465,93, in the level of 15% replacement and 2539,62 and 2421,81, with replacement of 30% of the diet reference, respectively. The values of dry matter, crude protein, crude fiber, calcium and phosphorus were 83,80%, 15,20%, 149,90g, 110g and 200g, respectively. From these results were verified the effects of bagasse of stalk of cashew apple in the diet of Japanese quails on performance, economic analysis and quality of eggs. It were used 160 quails from the species Coturnix coturnix japonica with 86 days of age, with an average production of 92%, then it was conducted an experiment in a completely randomized design, with four treatments (reference feed + 10, 20 and 30% of replacement) five replicates and eight quails per experiment unit, with four periods of 21 days. The bagasse of stalk of cashew apple enriched with 10,65% reached the highest egg weight, its replacement is economically feasible and does not compromise the zootecnic indexes, however, increased levels of bagasse of stalk of cashew apple should be evaluated according to the aspects of economics and market. For that the percentage of protein of bagasse of stalk of cashew apple remains unchanged, storage should be in a freezer after dry.
657

Uma formulação alternativa e enriquecida para elementos do tipo hermitiano 2-simplex / An alternative and enriched formulation for elements type hermitian 2-simplex

Dias, Nestor Juvenal Gianotti Terra 17 July 2014 (has links)
Made available in DSpace on 2016-12-12T20:25:11Z (GMT). No. of bitstreams: 1 Nestor Juvenal G Terra Dias.pdf: 2791426 bytes, checksum: ca6d2cf5b36479b660a86c2196aa3b25 (MD5) Previous issue date: 2014-07-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The main objective of this work was to obtain an alternative formulation for the so-called Hermitian 2-simplex type-(3) elements and enrich this formulation by adding functions with null value on all the nodes of the element, however with unitary partial derivatives one node. The conventional Hermitian element is an old element with degree p=3 and the degrees of freedom are the displacements and the partial derivatives in each node of the element. The element formulated in this work and their enriched versions have C0 continuity (C1 continuity is assured only at the element nodes). The formulation of the elements is based on the Principle of Minimum Potential Energy and because it is a displacement formulation, the prescribed Neumann (partial derivatives) or the Cauchy-Robin (mixed) boundary conditions are satisfied without any difficulty at the boundary nodes. Stresses and/or fluxes are obtained without any additional post-processing of finite element solution and with precision similar to the precision obtained for displacements. In this work these elements were applied to the solution of various problems of plane elasticity, axial-symmetric elasticity, free vibration of membranes and potential problems. The main emphasis in these analyzes was to study the rates of convergence obtained with homogeneous meshes and distorted meshes. Another aspect studied was the convergence for material locking problems (EPD) and special attention was given to the analysis of error in stress (or fluxes). After several comparisons made throughout this work it was concluded that the results obtained with this type of element is better than a large majority of triangular elements available in the literature. / Objetivo principal deste trabalho foi obter uma formulação alternativa para os chamados elementos Hermitianos 2-simplex do tipo (3) e enriquecer esta formulação adicionando funções com valor nulo em todos os nós do elemento, porém com derivadas parciais unitárias em apenas um destes nós. O elemento Hermitiano convencional é um elemento antigo na literatura, possui grau p=3 e os graus de liberdade do elemento são os deslocamentos e suas derivadas parciais em cada nó. O elemento formulado neste trabalho e sua versão enriquecida possuem continuidade C0 (a continuidade C1 só é assegurada nos nós do elemento). A formulação dos elementos é baseada no Princípio da Mínima Energia Potencial e por se tratar de uma formulação de deslocamento as condições de contorno de derivadas (Neumann) ou mistas (Cauchy-Robin) que são prescritas no contorno são satisfeitas sem nenhuma dificuldade. As tensões e/ou fluxos são obtidos sem nenhum pós-processamento adicional e com precisão semelhante à dos deslocamentos. Neste trabalho estes elementos foram aplicados para a solução de diversos problemas da elasticidade plana e axi-simétrica, problemas de vibração livre de membranas e problemas de potencial. A ênfase principal nestas análises foi o estudo das taxas de convergência com malhas homogêneas e com malhas distorcidas. Outro aspecto estudado foi a convergência para os problemas de locking de Poisson e especial atenção foi dada para as análises de erro em tensões (ou fluxos) pontuais que é o ponto forte deste tipo de elemento. Após diversas comparações realizadas ao longo deste trabalho concluiu-se que os resultados obtidos com este tipo de elemento são melhores do que a grande maioria de elementos triangulares disponíveis na literatura.
658

Exploiting isotopic enrichment for a solid-state NMR investigation of 'ADORable' zeolites and breathing metal-organic frameworks

Bignami, Giulia Paola Maria January 2018 (has links)
This thesis combines synthetic studies for isotopic enrichment with solid-state characterisation techniques to investigate two classes of microporous materials: zeolites and metal-organic frameworks (MOFs). These materials have a wide range of successful applications, from industrial catalysis to medicine, resulting in the increasing need for both a complete understanding of their unique structural features and synthetic methods to target new frameworks. Nuclear magnetic resonance (NMR) spectroscopy, thanks to its sensitivity to the local, atomic-scale, environment and its element specificity, is applied, in combination with powder X-ray diffraction (PXRD), electron microscopy, N2 adsorption and mass spectrometry, to the study of these materials. Oxygen atoms play a crucial role in the structure and chemistry of zeolites and MOFs, making 17O NMR an excellent tool for chemical and structural investigations. However, the low natural abundance of this isotope (0.037%) and the cost of 17O-enriched reactants require the development of atom-efficient synthetic processes for isotopic enrichment. In the first part of this work, the unconventional assembly-disassembly-organisation-reassembly (ADOR) method is applied to the Ge-doped UTL framework and optimised in reduced-volume conditions for economic enrichment to obtain 17O- and 29Si-enriched UTL-derived zeolites. In situ and ex situ solid-state characterisation studies show that isotopic enrichment not only enables a more detailed spectroscopic investigation, but also provides new insights into the mechanism of the ADOR process and its sensitivity to experimental conditions. In the second part of this work, dry gel conversion synthesis and a novel steaming procedure are studied as cost-effective 17O-enrichment pathways for Al, Ga and Sc mixed-metal terephthalate MOFs. 17O solid-state NMR spectroscopy, in combination with PXRD and electron microscopy, is employed to investigate cation disorder and 17O NMR spectra are shown to be sensitive to substitution of metal centers and conformational changes upon interaction with guest molecules.
659

Exercício físico e estimulação ambiental como estratégias terapêuticas após a hipoperfusão cerebral crônica em ratos Wistar : aspectos neurais, gliais e comportamentais

Cechetti, Fernanda January 2010 (has links)
O objetivo geral deste estudo foi verificar os efeitos terapêuticos do enriquecimento ambiental e do exercício físico forçado sobre as conseqüências funcionais e cognitivas da Hipoperfusão Encefálica Crônica (HEC) em ratos Wistar. Além disso, padronizamos protocolo alternativo de HEC, a fim de aumentar a taxa de sobrevivência característica deste modelo, juntamente com a análise comportamental e imunohistoquímica do sétimo ao sexto mês após a cirugia, analisando o comportamento de neurônios e astrócitos no hipocampo. Os resultados mostraram que o protocolo modificado, ou seja, com a oclusão das carótidas realizadas com uma semana de intervalo, apresentam resultados comportamentais e morfológicos similares aos do protocolo padrão; todavia, a taxa de sobrevida dos animais no protocolo modificado é significativamente maior quando comparados ao padrão. Além disso, em ambos os protocolos, os animais hipoperfundidos apresentam um déficit cognitivo no Teste Water Maze três meses após a cirurgia, mas os grupos isquêmicos não apresentaram diferenças morfológicas quando comparados ao seus controles em relação a volume total Hipocampal e área Estriatal. Ao analisar o tempo pós- lesão do déficit cognitivo, verificamos que a HEC causa danos comportamentais a longo prazo, chegando a seis meses após o evento isquêmico. Enquanto a cognição é afetada na fase crônica, as células neuronais e astrogliais são acometidas nas fases mais agudas deste modelo, começando a aparecer morte neuronal (através da quantificação de NeuN) e astrogliose reativa (através da quantificação do imunoconteúdo de GFAP) já nos primeiros dias, permanecendo até aproximadamente 3 meses após a lesão. Após o dano estabelecido, testamos estratégias terapêuticas com o objetivo de amenizar principalmente o dano cognitivo apresentado pelos animais a partir dos três meses após cirurgia. Inicialmente foi analisado o efeito pré e pós - isquemia do exercício físico forçado através de uma esteira para ratos na memória espacial e de trabalho, através do Water Maze e bioquimicamente no estado oxidativo cerebral. Posteriormente, os mesmos parâmetros foram testados, só que com a intervenção do enriquecimnto ambiental tanto pré quanto pós-isquemia também. O modelo de hipoperfusão cerebral crônica causa como citado anteriormente, um déficit bastante importante na memória e no apredizado. Somado a isso, em relação ao estresse oxidativo, a quantidade de radicais livres e o estado de lipoperoxidação celular encontra-se bastante aumentados no hipocampo de animais submetidos a isquemia, assim como as enzimas antioxidantes. O protocolo de atividade física regular forçada (3 vezes por semana, durante 20 minutos num período de 3 meses), sobretudo nos grupos pré e pré+pós-isquemia, preveniu os efeitos cognitivos e bioquímicos da HEC. Tal reversão também ocorreu com o uso do enriquecimento ambiental realizado 3 vezes por semana, 1 hora durante 3 meses em todos os grupos estimulados. / The aim of this study was to verify the experimental therapeutic effects of environmental enrichment and forced physical exercise on the consequences of cognitive and functional chronic cerebral hypoperfusion (CCH) in Wistar rats. To do that, a CCH alternative protocol was standardized, in order to increase the survival rate of this model, together with the behavioral and immunohistochemistry analysis done up to the sixth month after the surgery, analyzing hippocampus neurons and astrocytes. Results showed that the modified protocol, with occlusion of both carotid arteries performed with a one-week interval, presents morphological and behavioral results similar to the standard protocol; however, the rate of survival after the modified protocol was significantly greater when compared to the standard one. In addition, both protocols produced ischemic animals with cognitive deficits in the Water Maze Task, three months after the surgery, however with no gross morphological lesion, as assessed by hippocampal volume and estriatal area. The cognitive deficit in CCH rats is long lasting, reaching six months after the ischemic event. While the cognition is affected in the chronic phase of hypoperfusion, the neuronal and astrogliais cells are affected in acute phases of this model; neuronal death (through quantification of NeuN) and reactive astrogliosis (through quantification of imunocontent of GFAP) are already present in the first days and remain until approximately 3 months after the lesion. We tested therapeutic strategies with the aim of alleviating mainly the cognitive damage presented by animals, as from three months after surgery. Initially, the effects of preand post-ischemia forced physical exercise in spatial and working memory, through the Water Maze Tak and oxidative stress parameters were analyzed. Subsequently, we tested the effects of environmental enrichment, both pre- and post-ischemia. The model of chronic cerebral hypoperfusion as previously mentioned, causes an important deficit in spatial learning and memory; the free radicals content and cellullar lipid peroxidation is also substantially increased in the hippocampus of animals submitted to hypoperfusion, as well as the antioxidant enzymes. Forced regular physical activity protocol (20-min, 3 times per week during 12 weeks – moderate), especially in groups pre and pre+post-ischemia, warned cognitive and biochemical preventive effects in CCH rats; the same occurred with the use of enrichment environmental performed 1- hr, 3 times per week during 12 weeks in all groups stimulated.
660

Procedimentos e avaliação química de parâmetros de interesse nutricional de espinafre comercializado na Bahia.

Rocha, Silvia Regina Santos January 2009 (has links)
Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2013-04-23T13:47:47Z No. of bitstreams: 1 Silvia Rocha.pdf: 838054 bytes, checksum: 4b1ce47b2cf6d9f32b6b110adf7bcfd4 (MD5) / Made available in DSpace on 2013-04-23T13:47:47Z (GMT). No. of bitstreams: 1 Silvia Rocha.pdf: 838054 bytes, checksum: 4b1ce47b2cf6d9f32b6b110adf7bcfd4 (MD5) Previous issue date: 2009 / O espinafre produzido e mais consumido no Brasil, denominado como espinafre da Nova Zelândia (Tetragonia expansa), difere significativamente do espinafre verdadeiro (Spinacia oleracea) produzido em muitos países do hemisfério norte. As diferenças ocorrem não apenas na classificação botânica, mas em muitas das características químicas dos vegetais. No presente trabalho, foram avaliados os teores de alguns nutrientes e antinutrientes contidos no espinafre comercializado na Bahia, sendo avaliados quatro diferentes procedimentos de digestão das amostras de espinafre com ácido nítrico em sistema aberto. Os resultados obtidos a partir dos diversos procedimentos de pré-tratamento da amostra foram comparados para os vários analitos investigados (Al, Ca, Fe, Cu, Zn, Mn, Mg) e indicaram vantagens da inserção de uma etapa de pré-digestão. Adicionalmente, foram realizados testes de extração dos metais sob investigação em água e em soluções com diferentes níveis de acidez na presença e ausência de agente quelante (ácido etilenodiaminotetracético – EDTA) para avaliação do nível de interação dos metais com o vegetal e, por conseguinte, a disponibilidade destes minerais. Os resultados levaram a acreditar que as interações de Mg(II), Cu(II) e Mn(II) com o espinafre seco eram fracas, enquanto que as interações com Al(III), Ca(II) e Fe(III) eram mais intensas, devido a condições mais drásticas (acidez da solução ou presença de quelante) foram necessárias para maximizar a extração destes metais. Ao considerar informações previamente reportadas sobre os elevados teores de oxalato em espinafre e seus efeitos antinutricionais, foram investigados os teores de oxalato em amostras secas oriundas de amostras de espinafre verdadeiro e espinafre da Nova Zelândia cultivado na Bahia, empregando permanganometria. Para tanto foram realizados estudos sobre as melhores condições para extração de oxalato variando a acidez da solução extratora e os resultados obtidos foram comparados com os apresentados na literatura. Finalmente, foram realizados testes para avaliação da possibilidade de enriquecimento de espinafre com íons metálicos a partir de sucessivas etapas de extração (dessorção) e concentração (sorção) do íon no vegetal. Pôde ser constatado que os maiores níveis de sorção (18 ± 3 mg g-1) e repetitividade foram obtidas para íons cálcio, possivelmente devido ao oxalato existente nos espinafres. / Salvador

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