58 resultados para trace mineral requirements

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)


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This study reports the effects of dietary iron (Fe) deficiency and recovery on bone mineral composition and strength in anemic rats submitted to a hemoglobin (Hb) repletion assay. Weanling male Wistar rats were fed a low-Fe diet (12 mg/kg) for 15 days followed by 2 weeks of Fe repletion with diets providing 35 mg Fe/kg as either ferrous sulfate (n = 8) or ferric pyrophosphate (FP; n = 12). At final day of each period (depletion and repletion), Fe-adequate animals were also euthanized. Iron status (blood Hb, Hb Fe pool, Hb regeneration efficiency), tibia mineral concentrations (Ca, Mg, Fe, Cu, and Zn) and biomechanical properties were evaluated. Iron-deficient rats had lower tibia Fe and Mg levels and bone strength when compared to controls. Yield load and resilience were positively related to tibia Mg levels (r = 0.47, P = 0.02 and r = 0.56, P = 0.004, respectively). Iron repletion did not recover tibia Mg concentrations impaired by Fe deficiency. Moreover, bone elastic properties were negatively affected by FP consumption. In conclusion, bone mineral composition and strength were affected by Fe deficiency, whereas dietary Fe source influenced tibia Mg and resistance in the period during which rats were recovering from anemia.

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An integrated whole-rock petrographic and geochemical study has been carried out on kamafugites and kimberlites of the Late Cretaceous Alto Paranaiba igneous province, in Brazil, and their main minerals, olivine, clinopyroxene, perovskite, phlogopite, spinels and ilmenite. Perovskite is by far the dominant repository for light lanthanides, Nb, Ta, Th and U, and occasionally other elements, reaching concentrations up to 3.4 x 10(4) chondrite values for light lanthanides and 105 chondrite for Th. A very strong fractionation between light and heavy lanthanides (chondrite-normalized La/Yb from similar to 175 to similar to 2000) is also observed. This is likely the first comprehensive dataset on natural perovskite. Clinopyroxene has variable trace-element contents. likely due to the different position of this phase in the crystallization sequence; Sc reaches values as high as 200 ppm whereas the lanthanides show very variable enrichment in light over heavy REE, and commonly show a negative Eu anomaly. The olivine, phlogopite (and tetra-ferriphlogopite), Cr-Ti oxide and ilmenite are substantially barren minerals for lanthanides and most other trace elements, with the exception of Ba, Cs and Rb in mica, and V, Nb and Ta in ilmenite. Estimated mineral/whole-rock partition coefficients for lanthanides in perovskite are similar to previous determinations, though much higher than those calculated in experiments with synthetic compositions, testifying once more to the complex behavior of these elements in a natural environment. The enormous potential for exploitation of lanthanides, Th, U and high-field-strength elements in the Brazilian kamafugites, kimberlites and related rocks is clearly shown.

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Zircon recrystallization is a common process during high-grade metamorphism and promotes partial or complete resetting of the original isotopic and chemical characteristics of the mineral and thus complicates U-Pb geochronological interpretation. In Central Brazil, this complexity may be illustrated by three composite mafic-ultramafic intrusions metamorphosed under amphibolite-to-granulite conditions. Their ages of emplacement and metamorphic ages have been a matter of controversy for the last thirty years. The Serra da Malacacheta and Barro Alto complexes make up the southernmost of these layered bodies and four samples from distinct rock types were investigated in order to verify the consequences of metamorphic alteration of zircon for U-Pb dating. Cathodoluminescent imaging reveals internal features which are typical of concomitant dissolution-reprecipitation processes, such as convolute zoning and inward-moving recrystallization fronts, even in samples in which partially preserved igneous textures are observed. Due to this extensive alteration, LA-ICPMS U-Pb isotopic analysis yielded inconclusive data. However, in situ Hf isotopic and trace-element analyses help to clarify the real meaning of the geochronological data. Low Lu/Hf (<0.004) and homogeneous (176)Hf/(177)Hf(t) values imply that the zircon populations within individual samples have crystallized in a single episode, despite the observed variations in age values. Trace element signatures of zircon grains from garnet-bearing samples reveal that they were unreactive to the development of the peak metamorphism mineral assemblage and, thus, the main chemical feature in such grains is attributed to a coupled dissolution-reprecipitation process. However, in the Cafelandia amphibolite an additional alteration process is identified, probably related to the influx of late-stage fluids. Combined isotopic and geochemical investigation on zircon grains allowed the distinction of two magmatic events. The first corresponds to the crystallization of the Serra da Malacacheta Complex and characterizes a juvenile magmatism at similar to 1.3 Ga. The younger episode, recognized in the Barro Alto Complex, is dated at ca. 800 Ma and is represented by mafic and ultramafic rocks showing intense contamination with continental crust, implying that the emplacement took place, most likely, in a continental back-arc setting. Altered zircon domains as well as titanite grains date the metamorphic event at ca. 760-750 Ma. (C) 2011 Elsevier B.V. All rights reserved.

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The sustainability of intensive swine production demands alternative destinations for the generated residues. Ashes from swine rice husk-based deep bedding were tested as a mineral addition for cement mortars. The ashes were obtained at 400 to 600ºC, ground and sieved through a 325 mesh sieve (# 0.045 mm). The characterization of the ashes included the determination of the index of pozzolanic activity with lime. The ashes were also tested as partial substitutes of Portland cement. The mortars were prepared using a cement:sand proportion of 1:1.5, and with water/cement ratio of 0.4. Three percentages of mass substitution of the cement were tested: 10, 20 and 30%. Mortar performances were assessed at 7 and 28 days determining their compressive strength. The chosen condition for calcinations at the laboratory scale was related to the maximum temperature of 600ºC since the resulting ashes contained vitreous materials and presented satisfactory values for the pozzolanic index under analysis. The pozzolanic activity indicated promising results for ashes produced at 600ºC as a replacement of up to 30% in cement masses.

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Objetivou-se avaliar os efeitos da ingestão diária de quatro níveis de fósforo (8, 12, 15 e 18 g) sobre o metabolismo de macrominerais (P, Ca, Mg, Na, K e S), incluindo a ingestão, a concentração no rúmen, a taxa de passagem do líquido ruminal, a excreção nas fezes e a disponibilidade aparente. Utilizaram-se quatro bubalinos adultos com fístulas ruminais em delineamento quadrado latino (4 × 4) com dieta total constituída de cana-de-açúcar como volumoso (85%) e concentrado formulado com um dos níveis de fósforo. Os níveis de fósforo não ocasionaram diferença significativa na concentração mineral no rúmen de nenhum mineral estudado. A concentração média de fósforo no conteúdo ruminal foi de 0,98% na matéria seca, enquanto o teor de fósforo nas rações variou de 0,12 a 0,34%, comprovando alta reciclagem de fósforo pela saliva. Níveis crescentes de fósforo na dieta, variando de 8 a 18 g/animal/dia, não influenciam as disponibilidades de cálcio e magnésio. Com o nível de fósforo de 15 g/dia, houve melhor utilização do fósforo da dieta. A ingestão de níveis crescentes de fósforo em g/kg0,75 (X) promoveu aumento linear na excreção fecal desse mineral em g/kg0,75 (Y) e baixos valores de disponibilidade do fósforo, que pode ser estimado pela equação Y = 0,03 + 0,610X, o que indica deficiência desse elemento mineral na dieta para o metabolismo animal.

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In order to evaluate the effect of environmental temperature on ruminal fermentation and on mineral levels of growing ruminants, it was used 12 male calves (initial average weight 82.9 ± 7.7 kg, 100 days of age), were employed in a randomized block design (by weight) experiment, with repeated weight measurement and two environmental temperatures: thermoneutral (24ºC) and heat-stressed (33ºC), during 38 days. The animals exposed to 33ºC presented lower dry matter ingestion, lower T3 (triiodothyronine) serum level, higher ammoniacal nitrogen (NH3-N) level in the rumen liquid, and higher rectal and body temperatures during all the experimental period when compared to the animals kept in thermoneutral environment (24ºC). The animals kept under heat stress environment (33ºC) presented higher calcium serum level, which was the highest on 31st day and the lowest on the 38th day of the experiment; phosphorus level was the lowest during all the experimental period; sodium level was lower on the 17th, 31st and 38th experimental days. Potassium and zinc levels were lower after 24 days; copper level was lower until the 24th day; magnesium level was higher until the 17th day, if compared to the ones from the animals kept in thermoneutral environment (24ºC). The heat-stressed animals presented higher levels of ammoniacal nitrogen in the ruminal liquid and a decrease in the phosphorus, sodium, potassium and zinc serum levels. These results show the necessity of changes on feed management to ruminants in temperatures over the thermal comfort limits so that performance loss is decreased.

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Avaliou-se o efeito da suplementação protéica (40% PB) com amiréia ou uréia sobre o consumo de suplemento, desempenho e características econômicas de novilhos terminados em pastagens. Foram utilizados 120 novilhos com 19 meses de idade e 358kg, sendo 60 Nelore e 60 F1 Brangus x Nelore, divididos em três tratamentos com 20 animais, alojados em piquetes de Brachiaria brizantha cv. Marandu de 10 hectares cada, totalizando 120 hectares, sendo dois piquetes por grupo genético e tratamento, pastejados alternadamente a cada pesagem (42 dias). Os tratamentos consistiram em mistura mineral com amiréia-150S (AM), mistura mineral com uréia+milho+enxofre (UR) e mistura mineral (MM). As médias de consumo de suplemento dos animais F1 foram de 206,1; 145,9 e 73,1g/dia, e as dos animais Nelore, 236,0; 205,1 e 94,3g/dia para os tratamentos AM, UR e MM, respectivamente. Para os novilhos Nelore, houve efeito (P<0,05) do suplemento sobre o peso de abate (PA), sendo a média do tratamento UR, 518,85kg, mais alta que a dos demais, 491,89 e 485,20kg, respectivamente, para AM e MM. Para os novilhos F1, foi significativo o efeito da suplementação protéica (P<0,05), com médias de 515,90 e 520,15kg, respectivamente, para os tratamentos UR e AM. A suplementação protéica proporcionou bom desempenho em animais F1 durante períodos de abundância de forragem. O uso de uréia apresentou melhor viabilidade econômica.

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This study aimed to develop a diet quality index (DQI-a) adjusted for energy requirement. Dietary intake of adults was assessed using 24-hour food recall. The DQI was developed for scores evenly distributed across ten items characterizing different aspects of diet: food groups, nutrients, and variety. The components categorized under the food groups from the Dietary Guide for Brazilians were adjusted according to the estimated energy requirements of the population studied. Index consistency and correlation with nutrients of the diet was analyzed by Cronbach's alpha. A total of 737 individuals were assessed and energy requirements ranged from 1,800 to 2,500kcal among women and 2,500 to 3,400kcal in men. The food group with greatest variation in total portions was cereals and tubers. Cronbach's alpha of the DQI-a was 0.643 and the index correlated with most of the nutrients. The DQI-a can be considered a valuable instrument for assessing diet quality of the Brazilian population.

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The purpose of this study was to assess the concentration of vitamins and minerals in meat protein hydrolysates. Calcium, phosphorus and iron were analyzed by inductively coupled-plasma atomic emission spectrophotometry; vitamin C was analyzed by the reduction of cupric ions and vitamins B1 and B2 by fluorescence. Regarding minerals, the beef hydrolysate (BH) had more iron than the turkey hydrolysate (TH) and the chicken hydrolysate (CH); TH had a little more phosphorus. BH had the largest amount of vitamin C, and similar amounts of vitamins B1 and B2. The amount of these nutrients found in the hydrolysates suggests that it is possible to use them to enrich special dietary formulations.

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O estudo teve como objetivo avaliar os casos de urolitíase canina em que a composição mineral dos urólitos foi analisada quantitativamente. Foi avaliada quantitativamente a composição mineral de 156 urólitos obtidos de cães (nefrólitos, ureterólitos, urocistólitos e uretrólitos). Desse total, 79,5% (n=124) eram simples, 18% (n=28) eram compostos e apenas 2,5% (n=4) eram mistos. A estruvita foi o tipo mineral mais frequente nos urólitos simples (47,6%; n=59), em todos os mistos (100%; n=4) e nas camadas núcleo e pedra de urólitos compostos (32,1 e 75%, respectivamente). O oxalato de cálcio foi o segundo mineral mais frequente dos urólitos simples (37,9%, n=47). Ao contrário do que é preconizado para os urólitos simples, as recomendações para o tratamento de urólitos compostos são mais complexas, tais como protocolos de tratamento de dissolução diferentes (se composto por minerais distintos e passíveis de dissolução como urato e estruvita). Além disso, a dissolução pode não ser viável, caso ocorra presença de material insolúvel envolvendo o urólito ou se este representar mais de 20% da camada. Vinte e dois urólitos compostos (78,7%) apresentaram uma camada externa não passível de dissolução (oxalato de cálcio ou fosfato de cálcio); dois (7,1%) apresentaram camadas externas passíveis de dissolução (estruvita ou urato), porém camadas mais internas não solúveis, o que permitiria apenas a dissolução parcial do urólito. Assim, o conhecimento da composição de todas as camadas que compõem o urólito é essencial para o entendimento da formação do cálculo e consequentemente para a indicação do tratamento adequado, assim como para prevenção de recidivas.

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Objetivou-se avaliar os efeitos da inclusão de gordura de origem animal ou vegetal e de óleo mineral sobre a aceitabilidade, a digestibilidade dos nutrientes e as concentrações plasmáticas de triglicérides e colesterol em equinos. Utilizaram-se quatro potros de 13 a 16 meses de idade recebendo dieta contendo feno de gramínea e concentrado, em delineamento quadrado latino, analisado por contrastes ortogonais. A aceitabilidade não foi influenciada pela quantidade nem pelo tipo de óleo adicionado às dietas. Os menores valores de digestibilidade de matéria seca (MS), matéria orgânica (MO) e extrato etéreo (EE) foram observados para as dietas acrescidas de óleo mineral (58,90; 60,29 e 32,02%) em comparação à dieta controle, cujos valores foram de 62,58; 64,41 e 77,72%. O coeficiente de digestibilidade do EE obtido com a dieta com óleo mineral foi menor (32,02%) que o obtido para as dietas com gordura animal (90,26%) e gordura vegetal (86,47%). A dieta com óleo mineral reduziu a concentração de HDL-C (68,75 mg/dL) em relação à dieta controle (76,00 mg/dL). A adição de fontes lipídicas e óleo mineral não influencia na aceitabilidade da dieta por equinos. O óleo vegetal não se diferencia da gordura animal quanto à digestibilidade dos nutrientes, no entanto, essas fontes de lipídios afetam a digestibilidade do extrato etéreo. A adição de óleo mineral reduz os níveis plasmáticos de HDL-C, ao passo que a adição de gordura animal e gordura vegetal não altera as concentrações plasmáticas de colesterol.

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OBJETIVO: Avaliar a densidade mineral óssea (DMO) e relacioná-la com a ingestão alimentar e composição corporal de adolescentes modelos de passarela. MÉTODOS: Estudo transversal avaliando 33 modelos e 33 não modelos de 15 a 18 anos pareadas por idade e índice de massa corporal (IMC). A densidade mineral óssea da coluna (L1-L4) foi avaliada por meio da técnica da absorciometria de feixe duplo de energia (Lunar® DPX Alpha), e a composição corporal, pela técnica de pletismografia. A ingestão alimentar foi avaliada por meio do registro alimentar de 3 dias. RESULTADOS: A média de idade das adolescentes foi de 16,75±1,04 anos, sendo que 24 por cento apresentaram IMC abaixo dos valores ideais para a idade. Não houve diferença de DMO entre modelos (1,108±0,080 g/cm2) e não modelos (1,096±0,102 g/cm2) (p > 0,05), sendo identificada uma porcentagem de 6 por cento de baixa DMO para a idade. Observou-se que a média de ingestão de energia foi menor entre as modelos em comparação às adolescentesnão modelos (1.480,93±582,95 versus 1.973,00±557,63 kcal) (p > 0,05) e que a maioria das adolescentes de ambos os grupos apresentou consumo inadequado de micronutrientes, ressaltando-se a baixa ingestão de cálcio. Verificou-se correlação significativa da DMO apenas com a massa magra (kg) (modelos r = 0,362 e não modelos r = 0,618; p < 0,05). CONCLUSÃO: Apesar de não ter sido encontrada associação entre a DMO, o IMC e a ingestão de nutrientes importantes no processo de mineralização óssea, as inadequações na ingestão alimentar podem influenciar negativamente a aquisição de massa óssea, que se encontra potencializada neste estágio de vida

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The effects of temperature on the life table, and of seston quality on the individual growth and reproduction of cladocerans from a tropical lake were tested in the laboratory. Life-table experiments were carried out at 17 degrees C, 23 degrees C, and 27 degrees C. Growth bioassays tested the influence of natural seston fractions, separated by net filtration, on cladocerans. The treatments were: (1) total seston plus Scenedesmus spinosus (1 mg C.L(-1)), (2) seston <= 36 mu m, and (3) seston >36 mu m. Phytoplankton composition, density, and biomass were evaluated during growth experiments, together with sestonic carbon, nitrogen, and phosphorus concentrations. The intrinsic rates of natural increase were higher for Moina micrura and Daphnia ambigua at 27 degrees C compared to 17 degrees C. The age at first reproduction of both species was delayed at 17 degrees C. Growth rates and fecundity of M. micrura were higher in the seston fraction <= 36 mu m than in the fraction > 36 mu m. Higher growth rates and fecundity of Moina minuta were observed in the seston enriched with the green alga in comparison to the seston <= 36 mu m and > 36 mu m. Bosmina longirostris was unable to reproduce at 17 degrees C and to grow in the seston > 36 mu m in one experiment. High densities and/or biomass of large colonial and filamentous algae present in the larger seston fraction could have contributed to reduce growth and reproduction. Episodes of food-quantity limitation may occur, but there was no evidence of mineral limitation, although seston C:P and C:N ratios were always above the limiting values assumed for temperate water bodies. The C:P and C:N ratios arc highly influenced by carbon that originates primarily from resuspended detritus from the lake.

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Purpose: The purpose of this work was to evaluate the potential of substituting autogenous bone (AB) by bone marrow aspirate concentrate (BMAC). Both AB and BMAC were tested in combination with a bovine bone mineral (BBM) for their ability of new bone formation (NBF) in a multicentric, randomized, controlled, clinical and histological noninferiority trial. Materials and Methods: Forty-five severely atrophied maxillary sinus from 26 patients were evaluated in a partial cross-over design. As test arm, 34 sinus of 25 patients were augmented with BBM and BMAC containing mesenchymal stem cells. Eleven control sinus from 11 patients were augmented with a mixture of 70% BBM and 30% AB. Biopsies were obtained after a 3-4-month healing period at time of implant placement and histomorphometrically analyzed for NBF. Results: NBF was 14.3%+/- 1.8% for the control and nonsignificantly lower (12.6%+/- 1.7%) for the test (90% confidence interval: -4.6 to 1.2). Values for BBM (31.3%+/- 2.7%) were significantly higher for the test compared with control (19.3%+/- 2.5%) (p < 0.0001). Nonmineralized tissue was lower by 3.3% in the test compared with control (57.6%; p = 0.137). Conclusions: NBF after 3-4 months is equivalent in sinus, augmented with BMAC and BBM or a mixture of AB and BBM. This technique could be an alternative for using autografts to stimulate bone formation.

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We solve the operator ordering problem for the quantum continuous integrable su(1,1) Landau-Lifshitz model, and give a prescription to obtain the quantum trace identities, and the spectrum for the higher-order local charges. We also show that this method, based on operator regularization and renormalization, which guarantees quantum integrability, as well as the construction of self-adjoint extensions, can be used as an alternative to the discretization procedure, and unlike the latter, is based only on integrable representations. (C) 2010 American Institute of Physics. [doi:10.1063/1.3509374]