• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 152
  • 31
  • 5
  • 5
  • 5
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 228
  • 123
  • 47
  • 42
  • 42
  • 31
  • 29
  • 27
  • 25
  • 24
  • 24
  • 20
  • 20
  • 19
  • 19
  • 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.
171

Fontes de zinco e cobre de origem secundária: caracterização, solubilidade e disponibilidade à plantas de arroz / Sources of zinc and copper from secondary origin: characterization, solubility and availability to rice plants

Thiago Augusto de Moura 05 July 2010 (has links)
Pouco se conhece sobre a origem dos materiais utilizados na fabricação de micronutrientes. Muitos fertilizantes podem conter em sua matéria prima nutrientes em formas indisponíveis para as plantas. Este fato pode limitar a produção, pois, até 2007 a legislação não contemplava parâmetros de solubilidade mínima e concentração máxima de metais pesados tóxicos. Atualmente estes parâmetros presumem que a solubilidade mínima de 60% nos extratores, ácido cítrico e citrato neutro de amônio para zinco e cobre respectivamente e a extração de metais pesados tóxicos pelo método 3050B da Agência de Proteção Ambiental Americana (EPA) são suficientes em garantir fertilizantes eficientes e de baixo impacto ambiental.Fontes secundárias de origem industrial vêem sendo utilizadas para fabricação de fertilizantes no Brasil há muitos anos. Recentemente, o mistério da agricultura e órgãos ambientais tem questionado a origem destas matérias primas como possível fonte de contaminação por metais pesados tóxicos e também sua eficiência como fonte de micronutrientes. A indústria por outro lado declara que o uso destes materiais é uma questão favorável ao ambiente, pois permite uso de materiais que seriam descartados. Outra alegação são os altos preços das matérias primas autorizadas para uso, e há escassez de minerais disponíveis. Nesse sentido foram instalados experimentos com dois materiais secundários, A e B, de origem industrial com concentrações variadas de Zn e Cu. As fontes foram caracterizadas desde sua origem, avaliando-se processos, mineralogia por difração de raios X, concentrações de nutrientes e metais pesados tóxicos por fluorescência de raios X e determinação nos extratores HF, HCl concentrado, água-régia, 3050B, ácido cítrico 20g.L-1, citrato neutro de amônio (1:1). Após a caracterização conduziu-se experimento com a cultura do arroz, em casa de vegetação, para verificar os efeitos da aplicação destas fontes nas doses de (0;2,5;5;10;15 kg.ha-1 Zn) em um Latossolo Vermelho distroférrico. A análise dos difratogramas de raios X dos materiais secundários A e B mostraram diferenças quanto à cristalinidade, sendo este fenômeno melhor compreendido com os maiores teores de silício no material B obtidos na fluorescência de raios X. A cristalinidade das amostras traduziu-se em diferença entre os teores obtidos pelo diferentes extratores. Embora o material B ser agronomicamente ineficiente (IEA=49%), foi o único a ter as garantias mínimas de 60% de Cu e Zn atingidas e concentrações baixas de metais pesados tóxicos. Por outro lado, o material A apresentou desempenho agronômico satisfatório (IEA=94%) mas não atingiu solubilidade mínima em ácido cítrico 2% para Zn e cítrato neutro de amônio (1:1) para Cu, porem, apresentou maiores teores de metais pesados tóxicos, principalmente chumbo. Diante do exposto sugere-se que as matérias primas tenham sua origem caracterizada e rastreada nos fertilizantes, as extrações sejam realizadas em função da origem do material e que os níveis de metais pesados tóxicos sejam mais limitantes. / The origin of materials used in the manufacture of micronutrients is unexplored. Many fertilizers can contain nutrients in the raw material into unavailable forms to plants. This fact can limit the production because the legislation, until 2007, did not include parameters of minimum solubility and maximum concentration of toxic heavy metals. After that, these parameters assume that the minimum solubility of 60% in the extractors, citric acid, neutral ammonium citrate for zinc and copper respectively and the extraction of toxic heavy metals by the 3050B method of the U.S. Environmental Protection Agency (EPA) are enough to ensure efficient fertilizer and low environmental impact. Secondary materials from industrial have been used for the manufacture of fertilizers in Brazil for many years. Recently, the ministry of agriculture and environmental agencies have been questioned the origin of raw materials as possible source of contamination with toxic heavy metals and also its efficiency as a source of micronutrients. On the other hand, the industry, states that the use of these materials can be environmentally friendly because it allows using these materials that would be discarded. Moreover, the raw materials that are authorized for use are very expensive and there is scarcity of available minerals. Experiments in this direction have been realized with two secondary materials from industry, A and B, with several concentrations of Zn and Cu. The sources have been characterized since its origin, evaluating processes, mineralogy by x-ray diffraction, concentrations of nutrients and toxic heavy metals by x-ray fluorescence and analyzed by different extractants (HF, concentrated HCl, aqua regia, 3050B, 20 g L-1 citric acid, neutral ammonium citrate (1:1)) determined by flame spectrometry coupled plasma (ICP - MS). After characterization, greenhouse experiment was conducted with rice crop to check the effects of applying these sources at rates of (0, 2.5, 5, 10, Zn 15 kg ha-1) in an Oxisol. The analysis of X-ray diffraction patterns of secondary materials A and B showed differences in the crystallinity, this phenomenon was better understood with higher levels of silicon in material B, obtained by X-ray fluorescence analyzes. The crystallinity of the samples resulted in differences between the levels obtained by different extractants. Although material B be agronomically inefficient (AE=49%), was the only one with the minimum guarantees of 60% for Zn and Cu and low concentrations of toxic heavy metals. On the other hand, the material A had good agronomic performance (AE=94%) but did not reach minimum solubility in 2% citric acid for Zn and neutral ammonium citrate (1:1) for Cu. However, the levels of toxic heavy metals, mainly lead, were highest. To conclude, we suggest that the origins of raw materials needs to be characterized and traced in fertilizers, the extractions should be realized according to the origin of the material and the levels of toxic heavy metals should be more limitants.
172

Disponibilidade de energia e nutrientes nos domicílios: o contraste entre Regiões Norte e Sul do Brasil / Energy and nutrients disposal in residences: the contrast between North and South Regions of Brazil

Carla Cristina Enes 08 February 2006 (has links)
O consumo de alimentos é influenciado por inúmeros fatores, entre os quais podem ser destacados os culturais, nutricionais, socioeconômicos e demográficos. Reconhece-se que, na medida em que esses aspectos favorecem a adoção de novos padrões alimentares, também poderão causar repercussões distintas sobre os níveis de atendimento das demandas nutricionais da população. Neste trabalho foi utilizada como base de dados parcela das informações (referentes à população das Regiões Norte e Sul), obtidas por meio da Pesquisa de Orçamentos Familiares (POF 2002-2003), realizada pelo Instituto Brasileiro de Geografia e Estatística – IBGE. Dentre os objetivos da presente pesquisa destacam-se a análise da disponibilidade de energia e nutrientes, no âmbito dos domicílios. Visou-se também avaliar a participação dos grupos de alimentos e dos macronutrientes no Valor Energético Total - VET, bem como a variação dos mesmos segundo o rendimento mensal per capita e a localização do domicílio (rural e urbano). Para a elaboração das cálculos referentes ao conteúdo de energia e nutrientes, utilizou-se o software Virtual Nutri. Adotou-se como parâmetro para a avaliação da disponibilidade de vitaminas, minerais e fibras, os valores preconizados pelo Institute of Medicine (1997,1998, 2000, 2001, 2002). Quanto à avaliação do conteúdo de colesterol, adotou-se a recomendação da Organização Mundial da Saúde - OMS (2003). As análises estatísticas foram viabilizadas por meio do software SAS (1999). Para a avaliação da disponibilidade de energia e nutrientes conforme o rendimento mensal per capita, foi adotado o modelo de regressão múltipla. Dentre os resultados, destaca-se a reduzida disponibilidade (média) de energia para as famílias moradoras nas áreas urbanas de ambas as regiões e um incremento do conteúdo energético à medida que crescem os rendimentos. Quanto aos macronutrientes, verificou-se uma relação inversa entre a participação dos carboidratos no VET e os rendimentos familiares. A contribuição dos lipídios para o VET apresentou tendência de crescimento, de acordo com o aumento da renda. Com relação aos micronutrientes, os resultados revelaram reduzida disponibilidade, nos domicílios, das vitaminas C, B6, B12, D, E, folacina, ácido pantotênico e dos minerais cálcio, zinco, cobre, manganês e iodo para a totalidade das famílias integrantes da pesquisa. Salienta-se que o conteúdo dos minerais ferro, selênio e fósforo se aproximou do valor (médio) preconizado, apenas para as famílias das áreas rurais. A disponibilidade de fibras se revelou muito inferior ao valor mínimo recomendado para as famílias de ambas as regiões analisadas. A disponibilidade de colesterol revelou forte associação com os rendimentos familiares. Destaca-se a expressiva presença desse elemento, notadamente, nos domicílios das famílias da Região Sul. Quanto à participação dos distintos grupos de alimentos no VET, destaca-se a reduzida contribuição energética das frutas, verduras e legumes para praticamente a totalidade dos grupamentos familiares. Foi identificada a indesejável contribuição – considerada excessiva – dos doces, açúcares e refrigerantes para o VET disponível para as famílias. / Food consumption is influenced by countless factors, among which can be emphasized the cultural, nutritional, socioeconomic and demografic ones. One acknowledges that, as these aspects benefit the adoption of new nutritional patterns, it will also be possible to distinguish the level of fulfillment of nutritional demands of the population. Information obtained through the Family Budget Survey (POF 2002-2003), accomplished by Instituto Brasileiro de Geografia e Estatística – IBGE, concerning the population of the North and South Regions of Brazil was utilized as database in this work. An analysis of energy and nutrients disposal, at domiciliary extent, outstands among this researches’s main goals. It was also intended to assess the relative participation of groups of food and macronutrients in the Total Energetic Value – VET, as well as their variation according to the per capita monthly income and the situation of the place of residence (rural and urban). The Software Virtual Nutri was utilized for the elaboration of the analysis related to the energy and nutrients disposal. As a parameter for the assessment of vitamins, minerals and fibers disposal, it was adopted the recommendations prescribed by the Institute of Medicine (1997, 1998, 2000, 2001, 2002). Concerning the assessment of cholesterol content, the recommendation of the World Health Organization – (2003) was adopted. The statistical analysis were accomplished through the SAS (1999) Software. The multiple regression pattern was adopted in order to assess the energy and nutrients disposal, according to the per capita monthly income. Among the results, it outstands the low energy disposal for the families living in urban areas of both regions and an increase of energetic content while monthly income grows. Regarding macronutrients, it was verified a reversed relation between the participation of carbohydrates in VET and the family monthly income. The relative participation of fats presented a growth tendency proportional to an increase of income. In relation to micronutrients, the results showed a low disposal of vitamins C, B6. B12, D, E, folacin, pantotenic acid and mineral such as calcium, zinc, copper, manganese and iodin in residences for the families of North and South Regions in both geographic stratum. One emphasizes that the iron, selenium and phosphor contents approached the average forecast value only to the families of rural areas. The fiber disposal revealed to be much lower in relation to the minimum recommended value in both of the analyzed regions. The disposable content of cholesterol showed a strong association with the family incomes, with a notorious and expressive presence in residences of the South Region families. Regarding the participation of distinctive groups of food in VET, it outstands the reduced energetic contribution of fruits, vegetables and legumes for virtually all the familiary groupings. It was identified the undesirable contribution of sweets, sugars and soft drinks to the disposable VET for the families that participated in the research.
173

The anthropometric status and dietary intake of adults engaging in bodybuilding programme around Polowane Municipality in Limpopo Province

Masoga, Sylven January 2017 (has links)
Thesis (M. Sc. (Dietectics)) -- University of Limpopo, 2017 / Introduction: Bodybuilders around Polokwane municipality are adhering to different dietary practices some of which are not evidence based. These practices may predispose these athletes to negative health outcomes sooner or later in life. The aim of this study was to investigate the anthropometric status and dietary intake of bodybuilders around Polokwane Municipality. Methodology: This was a descriptive analytical study where purposive sampling method was used to obtain 51 out of 65 registered bodybuilders within the training gyms around Polokwane. Weight and Height were measured to determine BMI. Four skinfold sites (triceps, biceps, subscapular and suprailliac) were measured using caliper and non-stretchable tape to estimate total body fat percentage. Dietary information was collected using the 24 hour-recall collected for three different days which was validated by the Food Frequency Questionnaire. Results: of the 51 body builders, 94.1% were men and 5.8% women. Few athletes (15.7%) were using ergogenic agents such as powders (13.7%) and tablets (2%). Also, 64.7% of the athletes had normal body weight while 33.3% and 2.0% were overweight and obese respectively. Majority of the athletes (78.4%) had an acceptable body fat percentage. Dietary results showed that majority of the athletes consumed energy (98%) and carbohydrates (100%) below the ISSN bodybuilding recommendations. Conclusion: The dietary intake of the bodybuilding athletes around Polokwane municipality is below the ISSN (2010) bodybuilding recommendations; however, their anthropometric status and body composition is normal.
174

The Development of the Total Nutrient Index

Alexandra Elizabeth Cowan (7040936) 18 April 2022 (has links)
<p>Dietary supplement (DS) use is highly prevalent in the U.S. and can contribute substantial amounts of micronutrients to the one-half of U.S. adults and nearly one-third of U.S. children who use them. Despite their pervasive use, the best practices for assessing the prevalence of use of and measuring nutrient intakes from supplemental sources remain largely unknown, and currently no metric designed to assess total micronutrient exposures from foods, beverages, and DS exists. Comprehensive and robust methods for assessing the prevalence of use of and nutrient intakes from DS are critical for population-level research and surveillance. </p> <p>Therefore, the overarching aims of the research presented in this dissertation were to 1) identify the most comprehensive method for assessing the prevalence of use of and estimating nutrient intakes from DS, 2) characterize DS use and examine trends in overall and micronutrient-containing DS use among the U.S. population using multiple modes of DS assessment, 3) develop the first micronutrient-based diet quality index designed to capture usual intakes from all sources of under-consumed micronutrients among the U.S. population (i.e., the Total Nutrient Index (TNI)) and 4) to determine if the TNI is a useful measure for assessing total micronutrient exposures among the U.S. adult population.</p> <p>National Health and Nutrition Examination Survey (NHANES) 2011-2014 data among U.S. adults were employed to evaluate four combinations of methods constructed from two data collection instruments (i.e., the 24-hour dietary recall (24HR) and the NHANES in-home inventory with a frequency-based DS prescription medicine questionnaire (DSMQ)) for measuring the prevalence of use of and amounts of selected nutrients from DS. The results from the analysis indicated that a higher prevalence of DS use is reported when using frequency-based methods, like the DSMQ, but higher nutrient amounts are reported on the 24HR. Thus, combining the DSMQ with at least one 24HR (i.e., DSMQ or ≥1 24HR) provides the most comprehensive approach for measuring DS use and estimating nutrient intakes from supplemental sources among U.S. adults.</p> <p>Differences in the estimated prevalence of use of DS on the DSMQ or ≥1 24HR as compared with the DSMQ only were also noted among a nationally representative sample of the U.S. population from the 2007-2018 NHANES. When characterizing DS use and examining trends in overall and micronutrient-containing DS use among the U.S. population using multiple modes of DS assessment, increases in both overall and micronutrient-containing DS use were observed over time, but the prevalence of use was lower on the DSMQ than the DSMQ or ≥1 24HR among the total population and across all population subgroups. Therefore, the findings from this study were congruent with our previous analysis and contributed to a growing body of literature that utilizes multiple methods of DS assessment to improve the comprehensiveness of DS exposure assessment. </p> <p>The insights garnered from identifying the most comprehensive method for approximating micronutrient intakes from supplemental sources were implemented in the development and initial application of the first micronutrient-based diet quality index designed to capture usual intakes from all sources of under-consumed micronutrients among the U.S. population, named the TNI. The TNI assesses U.S. adults’ total nutrient intakes relative to the Recommended Dietary Allowance or Adequate Intake for eight under-consumed micronutrients identified by the Dietary Guidelines for Americans: calcium, magnesium, potassium, choline, and vitamins A, C, D, E. In the initial application of the TNI, based on dietary data from the 2011-2014 NHANES, the mean TNI score of U.S. adults was 75.4 out of 100, whereas the mean score when ignoring contributions from DS was only 69.0 (t-test; p<0.001). Therefore, the results from this analysis suggested that the TNI extends existing measures of diet quality by including nutrient intakes from all sources.</p> <p>However, another analysis designed to examine the construct and criterion validity of the TNI was completed using data from a nationally representative sample of U.S. adults who participated in the 2011-2014 NHANES, as well as exemplary menus reflective of high-quality diets. The results showed that the TNI yielded high scores on exemplary menus (84.8-93.3 out of 100), was moderately correlated with the Healthy Eating Index-2015 (r=0.48) and was able to differentiate between groups with known differences in nutrient intake for DS users vs. non-DS users, non-smokers vs. smokers, and those who were food-secure vs. food insecure (all <em>p</em><0.001). Moreover, correlations of TNI component scores with nutritional biomarkers for vitamins A, C, D, and E were significantly higher when compared with those obtained via the diet alone.</p> <p>Taken together, the research findings from the studies presented in this dissertation contribute evidence supporting the use of multiple modes of DS assessment to improve the comprehensiveness of DS exposure assessment, as well as the importance of capturing micronutrient exposures from all sources. These results also highlight the broad applicability of the TNI framework as a tool for comprehensively representing the totality of nutrient exposures, inclusive of DS. Our outcomes point towards a need for additional investigation into the random and systematic error that pervades DS assessment, the development of tools that can be used to describe micronutrient exposures more completely and how those relate to nutritional status, as well as further applications of the TNI. </p>
175

Macro- and micronutrient effects on stream biofilm and lake phytoplankton communities

Stoll, Jordyn Taylor 28 July 2023 (has links)
No description available.
176

Macro- and Micronutrient Intake in Children with Avoidant/Restrictive Food Intake Disorder

Schmidt, Ricarda, Hiemisch, Andreas, Kiess, Wieland, von Klitzing, Kai, Schlensog-Schuster, Franziska, Hilbert, Anja 05 May 2023 (has links)
Although case studies in avoidant/restrictive food intake disorder (ARFID) indicate severe nutritional deficiencies in those with a highly limited amount or variety of food intake, systematic analyses on food intake in treatment-seeking children and adolescents with ARFID are lacking. Within this study, n = 20 patients with an interview-based diagnosis of ARFID (0–17 years) were included and compared to n = 20 healthy controls individually matched for age and sex. Children or parents completed three-day food diaries and a food list. Macronutrient, vitamin, and mineral supply was determined based on the percentage of their recommended intake. The results showed a significantly lower total energy and protein intake in ARFID versus controls, with trends for lower fat and carbohydrate intake. ARFID subtypes of limited amount versus variety of food intake significantly differed in macro-, but not micronutrient intake. Those with ARFID met only 20–30% of the recommended intake for most vitamins and minerals, with significantly lower intake relative to controls for vitamin B1, B2, C, K, zinc, iron, and potassium. Variety of food intake was significantly reduced in ARFID versus controls in all food groups except carbohydrates. This study demonstrated that ARFID goes along with reduced everyday life macro- and micronutrient intake, which may increase the risk for developmental and health problems. Future studies additionally assessing serum nutrient levels in a larger sample may further explore differences in food intake across diverse ARFID presentations.
177

The impact of early nutrition on extremely preterm infants

Stoltz Sjöström, Elisabeth January 2014 (has links)
Background Modern neonatal care has improved the survival rate of extremely preterm infants. These infants are at high risk of malnutrition and growth failure during 3-4 months of hospital care. The objectives of this study was to investigate nutritional intakes during hospitalization and explore associations between nutritional intakes, postnatal growth and retinopathy of prematurity (ROP). Perioperative nutrition in infants undergoing surgery for patent ductus arteriosus (PDA) was also investigated. Methods This is a population-based study of Swedish extremely preterm infants (&lt;27 weeks) born during 2004-2007 (n=602). Detailed data on nutritional supply and anthropometric measurements during hospitalization were retrospectively retrieved from hospital records. Comprehensive data on cohort characteristics, neonatal morbidity and infant mortality were obtained from the Extremely Preterm Infants in Sweden Study (EXPRESS). Results During the first 70 days of life, intakes of energy, protein and several micronutrients, with the exception of iron and some vitamins, were less than estimated requirements, and infants showed severe postnatal growth failure. Energy and protein intake predicted growth in all anthropometric outcomes even when adjusting for severity of illness, and fat intake was positively associated with head growth. Low folate intake was positively correlated with poor weight and length gain while high iron intake, mainly explained by blood transfusions, was negatively associated with poor length gain. Furthermore, a low energy intake was associated with severe ROP (stage 3-5). An increased energy intake of 10 kcal/kg/d was associated with 24% decrease in severe ROP (p=0.01). During the first month, 99% of the infants were exclusively fed human milk. Infants who underwent surgery for PDA (n=140) were malnourished, with energy and macronutrient intakes below minimum estimated requirements before, during and after surgery. Conclusions The severe postnatal growth failure observed in Swedish extremely preterm infants may be prevented by improved intakes of energy, protein, fat and folate and a reduction of the number of blood transfusions. Human milk is the main enteral food source and analyses of human milk macronutrient contents facilitates individualized fortification. Provision of adequate energy intakes during the first four weeks of life may be an effective way to reduce the risk of severe ROP. Perioperative nutrition in infants undergoing PDA surgery needs to be improved. The study results have important implications for nutritional regimens, postnatal growth and health outcome in this new generation of survivors.
178

Uso de resíduos galvânicos como materiais secundários de interesse agronômico: avaliação das reações de solubilização e do risco ambiental / Use of galvanic wastes as secondary materials of agronomic interesting: evaluation of solubilization reactions and environmental risk

Mattos, Cleiton dos Santos 18 April 2017 (has links)
Este trabalho objetiva avaliar o uso de resíduos galvânicos de douração/prateação como fonte de micronutrientes (principalmente cobre e níquel) para as plantas, estudando as reações químicas que determinam os processos de solubilidade e adsorção na interface solo-solução-planta. Para isso, resíduos galvânicos foram caracterizados por ICP OES e FAAS, determinando os teores de Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, S e Zn após digestão ácida, detectando Cu entre 2 e 35% e Ni entre 0,007 e 9,7% (m/m), e baixas quantidades de Cd, Cr e Pb em relação aos anteriores. Aspectos físico-químicos caracterizam os resíduos como aglomerados quebradiços, com possível ordenação estrutural na forma de sulfatos, óxidos, hidróxidos ou carbonatos, sendo pouco higroscópicos e facilitando, assim, aplicação agronômica na forma pulverizada. Ensaios de solubilidade em meio aquoso por sistema em fluxo indicaram a dependência da solubilidade de cobre e níquel ao pH. Cobre já apresentaria melhor solubilidade em pHs inferiores a 5, o que não ocorreu, mas simulações em software de equilíbrio químico indicaram solubilidade de cobre no formato de brochantita [Cu4SO4(OH)6] em pHs abaixo de 3, e análises por DRX confirmaram sua presença. Dois dos resíduos utilizados apresentaram solubilidade de níquel em água, provavelmente como NiCl2 ou NiSO4, e todos apresentaram boa solubilização quando complexados com DTPA. Estudos de adsorção e difusão de Cu e Ni em solos por percolação de água em colunas de PVC, após adição de pastilhas de resíduos galvânicos ao meio, mostraram baixa mobilidade dos metais e influência da presença destes pela dissolução das pastilhas, intensificando as reações de adsorção e dessorção. Quando combinados com as isotermas de adsorção e extração sequencial, conclui-se que os solos apresentam elevada capacidade máxima de adsorção e que estes metais estão ligados na maior parte às frações menos disponíveis, mas apresentando aumento da disponibilidade após inserção dos resíduos. Ensaios de solubilidade na presença de plantas em sistema similar ao experimento de adsorção, porém, com os resíduos na forma pulverizada, mostraram a presença de Cu e Ni nas raízes por influência da inserção dos resíduos e na parte aérea somente para níquel, talvez por suficiência nutricional de cobre. As principais reações que ocorrem na interface solo-solução-planta, como de adsorção/dessorção, precipitação/dissolução, complexação e oxirredução, explicam os mecanismos da maior ou menor disponibilidade destes micronutrientes, favorecendo determinadas condições pelos conceitos de equilíbrio químico. Ácidos orgânicos exsudados na rizosfera podem acidificar o meio ou complexar os metais, aumentando sua solubilidade e favorecendo seu transporte para as plantas. Por isso, é recomendado que os resíduos sejam aplicados bem próximo às raízes. Ensaios microbiológicos mostraram que os resíduos apresentam baixa toxicidade, e, associado aos fatos da baixa mobilidade de Cu e Ni e da baixa influência dos contaminantes Cd, Cr e Pb no solo, estima-se que oferecem baixo risco ambiental. O conjunto de resultados confere aos resíduos galvânicos de douração/prateação viabilidade para serem utilizados como fertilizantes agrícolas para suprir deficiências de cobre e níquel, concordando com os objetivos da Política Nacional de Resíduos Sólidos, que estimulam a reciclagem de materiais perigosos, para que voltem à cadeia produtiva, evitando, assim, o desperdício de seu potencial por meio do descarte / This work aims evaluate the use of galvanic wastes of gold/silver-plating as micronutrients source (mainly copper and nickel) for plants, by studying the chemical reactions which determine the solubility and adsorption processes on the soil-solution-plant interface. For this purpose, galvanic wastes were characterized by ICP OES and FAAS, determining the levels of Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, S and Zn after acid digestion, detecting Cu in the range of 2 and 35% and Ni in the range of 0.007 and 9.7% (m/m), and low quantities of Cd, Cr and Pb compared to the previous ones. Physicochemical aspects characterize the wastes as brittle conglomerate, with possible structural ordination in the form of sulfates, oxides, hydroxides or carbonates, low hygroscopicity and facilitating, thus, agronomic application in the pulverized form. Solubility essays in aqueous media by flow system indicating the dependency of copper and nickel solubility with pH. Cupper would present better solubility in pH below 5, what did not happen, but simulations in chemical equilibrium software indicated copper solubility in the form of brochantite [Cu4SO4(OH)6] in pH below 3, and DRX analysis confirmed the their presence. Two of the wastes used presented nickel solubility in water, probably as NiCl2 or NiSO4, and all presented good solubilization when complexed with DTPA. Adsorption and diffusion studies of Cu and Ni in soils by water percolation in PVC column, after addiction of galvanic wastes tablets to the center, demonstrated low metals mobility and influence of their presence by the tablet dissolution, intensifying the adsorption and desorption reactions. When combined with the adsorption isotherms and sequential extraction, it concludes that the soils presented high maximum adsorption capacity and these metals are mostly bonded to less available fractions, but presenting an increasing availability after wastes addition. Solubility essays in the present of plants in a similar system to the adsorption experiment, however, with the wastes in the pulverized form, demonstrated the presence of Cu and Ni in the roots by the influence of the residues insertion and only nickel in the aerial parts, maybe by nutritional sufficiency of copper. The main reactions that occurred in the soil-solution-plant interface, as adsorption/desorption, precipitation/dissolution, complexation and redox, explain the mechanism of the higher or lower availability of these micronutrients, favoring determinate conditions by the chemical equilibrium concepts. Organic acids exuded in the rhizosphere can acidify the medium or complex the metals, increasing their solubility and favoring their transport to the plants. Therefore, it is recommended that the residues must be applied very close to the roots. Microbiological tests have shown that the wastes present low toxicity, and, associated with the low mobility of Cu and Ni and with the low influence of the Cd, Cr and Pb in the soil, it estimated to offer low environmental risk. The results set gives galvanic wastes of gold/silver-plating viability to be used as agricultural fertilizers to supply copper and nickel deficiencies, in line with the objectives of the National Solid Waste Policy, which encourages the recycling of hazardous materials, to get back to productive chain, thus avoiding the waste of its potential by means of the discard
179

Fatores dietéticos associados à  calcificação vascular em pacientes com doença renal crônica em tratamento conservador / Dietary factors associated with vascular calcification in non-dialysis chronic kidney disease patients

Machado, Alisson Diego 12 December 2017 (has links)
INTRODUÇÃO: A calcificação vascular (CV) é uma condição comum na doença renal crônica (DRC) e está associada a um maior risco de mortalidade, eventos cardiovasculares e outras comorbidades. A dieta pode ser importante na fisiopatologia da CV e um alvo em potencial para medidas terapêuticas, mas o seu papel ainda não é claro. Assim, o objetivo deste estudo foi avaliar a associação entre o consumo de energia, macro e micronutrientes e CV em pacientes com DRC em tratamento conservador. MÉTODOS: Foram analisados os dados da linha de base de 454 participantes do estudo PROGREDIR. O consumo alimentar foi avaliado por meio de um questionário de frequência alimentar e a ingestão de nutrientes foi ajustada pela energia pelo método dos resíduos. A calcificação arterial coronária (CAC) foi mensurada por tomografia computadorizada sem contraste e apresentada pelo escore de cálcio de Agatston. Após a exclusão dos participantes que utilizavam stent coronário, as análises foram realizadas em 373 pacientes. Inicialmente, considerando-se a distribuição assimétrica da CAC e a não independência entre a ingestão de nutrientes, a associação entre a CAC e o consumo alimentar foi avaliada modelos lineares generalizados mistos. Devido à colinearidade entre os nutrientes, em seguida foi utilizada a regressão de LASSO para identificar os nutrientes mais relacionados à variabilidade da CAC. RESULTADOS: A mediana da idade e da CAC foi de 68 (60, 76) anos e 165 (8, 785), respectivamente. O maior tercil de CAC se associou diretamente à ingestão de fósforo, cálcio e magnésio. Houve um maior consumo de vitamina A, ácido pantotênico e potássio no segundo tercil. Após ajustes para variáveis de confusão (idade, sexo, diabetes mellitus e tabagismo como efeitos fixos e o indivíduo como efeito aleatório), a ingestão de ácido pantotênico (? = 0,48; IC95% 0,22, 0,75; p < 0,001), fósforo (beta = 0,38; IC95% 0,10, 0,65; p = 0,01), cálcio (beta = 0,0008; IC95% 0,0001, 0,0017; p = 0,04) e potássio (beta = 0,0005; IC95% 0,0001, 0,009; p = 0,02) permaneceram associadas à CAC nos modelos lineares generalizados mistos. Devido à colinearidade entre esses nutrientes, foi utilizada a regressão de LASSO para avaliar os nutrientes mais associados à variabilidade da CAC. Nessa abordagem, os nutrientes que mais explicaram a variância da CAC foram o fósforo (beta = 0,25), o cálcio (beta = 0,09) e o potássio (beta = 0,06). CONCLUSÕES: Houve associação entre a CAC e o consumo de fósforo, cálcio e potássio em uma população com DRC. Estudos futuros são necessários para confirmar esses resultados e avaliar o papel de intervenções sobre a prevenção e progressão da CAC baseadas nesses micronutrientes / BACKGROUND: Vascular calcification (VC) is a widespread condition in chronic kidney disease (CKD) and is associated with a higher risk of mortality, cardiovascular events, and other comorbidities. Diet may play an important role in VC and is a potential target for therapeutic measures, but this role is not clear. Thus, the aim of this study was to evaluate the association between energy, macro-and micronutrient intakes and VC in non-dialysis CKD patients. METHODS: We analyzed the baseline data from 454 participants of PROGREDIR study. Dietary intake was evaluated by a validated food frequency questionnaire and nutrient intakes were adjusted for energy by residual method. Coronary artery calcification (CAC) was measured by non-contrast computed tomography and was presented by Agatston calcium score. After exclusion of participants with coronary stent, 373 people remained for the analyses. Initially, taking into account the asymmetrical distribution of CAC and the non-independence between nutrient intakes, we evaluated the association between CAC and dietary intake by generalized linear models and generalized linear mixed models. To address the collinearity between nutrients, we next evaluated the nutrients mostly related to CAC variability by LASSO regression. RESULTS: Median age and CAC were 68 (60, 76) years old and 165 (8, 785), respectively. The highest tertile of CAC was directly associated with the intake of phosphorus, calcium and magnesium. There was a higher intake of vitamin A, pantothenic acid and potassium in the second tertile. After adjustment for confounding variables (age, gender, diabetes mellitus and tobacco use as fixed effects and individual as random effect), the intake of pantothenic acid (? = 0.48; CI95% 0.22, 0.75; p < 0.001), phosphorus (beta = 0.38; CI95% 0.10, 0.65; p = 0.01), calcium (beta = 0.0008; CI95% 0.0001, 0.0017; p = 0.04) and potassium (beta = 0.0005; CI95% 0.0001, 0.009; p = 0.02) remained associated with CAC in the generalized linear mixed models. In order to handle the collinearity between these nutrients, we used the LASSO regression to evaluate the nutrients associated with CAC variability. In this approach, the nutrients that most explained the variance of CAC were phosphorus (beta = 0.25), calcium (beta = 0.09) and potassium (beta = 0.06). CONCLUSIONS: We found an association between CAC and the intake of phosphorus, calcium and potassium in a CKD population. Future studies are needed to confirm these findings and assess the role of interventions on these micronutrients on CAC prevention and progression
180

Der Einfluß von Mikronährstoffen auf die Therapie und die Reinfektion der durch Schistosoma haematobium hervorgerufenen Bilharziose bei tansanischen Kindern

Kaul, Eike Juliane 22 March 2006 (has links)
Praziquantel ist das Mittel der Wahl bei der Behandlung der Bilharziose. Für die Wirksamkeit des Medikaments spielt die Immunantwort des Wirts eine wichtige Rolle. Mikronährstoffe sind wichtig für die Funktion des Immunsystems. In Endemiegebieten der Bilharziose findet sich meist ein Mikronährstoffmangel. In dieser Studie wurde untersucht, ob ein Ausgleich des Mikronährstoffmangels das Behandlungsergebnis optimieren kann und Reinfektionen vermindert werden können. Für die randomisierte Interventionsstudie wurden 331 infizierte Kinder zwischen acht und 14 Jahren mit einer Eiausscheidung von über 30 Schistosoma haematobium Eiern pro 10 ml Urin ausgewählt. Die Kinder wurden zuvor in einer an zehn Grundschulen erhobenen Querschnittsstudie in einem blasenbilharzioseendemischen Gebiet in Tansania identifiziert. Die Interventionsgruppe erhielt vier Wochen lang ein Mikronährstoffpräparat und wurde danach mit Praziquantel behandelt, die Kontrollgruppe erhielt nur Praziquantel. Bei der Kontrolle des Therapierfolgs fanden sich keine signifikanten Unterschiede zwischen der Interventions- und der Kontrollgruppe hinsichtlich der Heilungsraten und der Infektionsstärke der Nichtgeheilten. Nach zehn Monaten wurden die Kinder nochmalig auf Eier im Urin untersucht, um Reinfektionen festzustellen. Fehlende bzw. spärliche Niederschläge machten jedoch Neuinfektionen fast unmöglich, da sich kaum Wasserstellen gebildet hatten, welche die Habitate von Bulinus nasutus - dem Zwischenwirt von S. haematobium im Untersuchungsgebiet - darstellen. Es waren nur 10 % der Kinder reinfiziert mit sehr geringen Infektionsstärken ohne signifikante Unterschiede zwischen den Studiengruppen. Es konnte nicht nachgewiesen werden, dass eine Mikronährstoffgabe den Therapieerfolg nach der Behandlung mit Praziquantel verbessern kann. Ob Reinfektionen verringert werden können, ließ sich aufgrund der anhaltenden Dürre in den Jahren 1999 und 2000 in dieser Studie nicht feststellen, sollte aber Gegenstand weiterer Studien sein. / Praziquantel is the drug of choice for schistosomiasis chemotherapy. The immune response of the host is an important factor in drug efficacy. Micronutrients are essential for an effective response of the immune system. In areas endemic for S. haematobium people often suffer from micronutrient deficiency. It was investigated whether a compensation of micronutrient deficiency can improve chemotherapy and reduce the rate and levels of reinfection. 331 children aged 8 to 14, highly infected with S. haematobium were selected for the randomised intervention-study. Children were identified in a cross-sectional study in 10 primary schools in Tanzania in an area endemic for S. haematobium. The intervention-group received a four weeks micronutrient supplementation followed by treatment with Praziquantel. The control-group was only treated with Praziquantel. The results showed no significant differences concerning cure rate and intensity of infection between the two study groups. The children were examined for reinfection ten months after treatment. Only ten percent of the children were reinfected with rather low levels of infection. There were no significant differences between the studied groups. Scarce rain during the rainy season inhibited the formation of the usual puddles, that form the essential habitat for Bulinus nasutus - the intermediate host of S. heamatobium. This substantially reduced the probability for new infections. It could not be confirmed whether micronutrient supplementation could improve the results after chemotherapy with Praziquantel. A decrease of reinfections due to micronutrient supplementations could not be confirmed due to the drought in 1999 and 2000, but should be a field for further investigations.

Page generated in 0.0795 seconds