778 resultados para potassium nutrition


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O objetivo deste trabalho foi avaliar o efeito da aplicação superficial de lodos de esgoto, lama cal, escória de aciaria e calcário sobre o estado nutricional e a produtividade da soja, em sistema plantio direto. O delineamento foi o de blocos ao acaso em arranjo fatorial 4x4+1, constituído por quatro tratamentos - resíduos de lodo de esgoto centrifugado (LC) e de biodigestor (LB), escória de aciaria (E) e lama cal (Lcal) - nas doses 0, 2, 4 e 8 Mg ha-1, mais o controle com 2 Mg ha-1 de calcário. As plantas de soja apresentaram maior concentração de nitrogênio, fósforo e cálcio, em 2003, 2004 e 2005, e de potássio, em 2003 e 2004, em razão dos tratamentos LC, LB, E, Lcal e calagem. A produtividade da soja foi favorecida pela aplicação dos tratamentos no sistema plantio direto, em 2003, 2004 e 2005. O fósforo, e o cálcio contribuíram para o aumento da produtividade da soja em 2003 e 2004.

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This study aimed to evaluate the effect of substituting chemical nitrogen (N) fertilization for equivalent N levels from sewage sludge of Wastewater Treatment Plant (WTP) on sunflower plant development. Nutrient levels in physiologically mature leaves and seeds, besides nutrient exportation during a 130-day assay, were also assessed. The experiment was carried out in 100 m(2) permanent plots at Sao Manuel Farm, which belongs to School of Agronomical Sciences, São Paulo State University-UNESP, Botncatu, São Paulo State, Brazil. The farm is located in the municipality of Sao Manuel, São Paulo State. Experimental design was in randomized blocks including 5 treatments and 5 replicates. Treatments were: T1 - chemical N fertilization according to the recommendation for the culture; T2 - 50% N from sewage sludge and 50% N from chemical fertilization; T3 - 100% N from sewage sludge; T4 - 150% N from sewage sludge; T5 - 200% N from sewage sludge. For all treatments, equal amounts of P and K fertilization were applied. Treatments differed for plant height from 21 to 64 days, stern diameter from 28 to 57 days, and leaf number from 21 to 38 days. Seed nutrient levels slightly varied; however, the quantities of exported N, P, Mg, Fe and Zn varied as sewage sludge levels increased.

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O presente trabalho objetivou avaliar o estado nutricional da bananeira-'Prata-anã' durante cinco ciclos de cultivo com adubação orgânica, no município de Botucatu-SP. As plantas foram adubadas com composto orgânico produzido a partir de serragem de madeira e esterco bovino, em que os tratamentos foram constituídos de doses desse composto (0; 98,5; 197,0; 290,5 e 394,0 g de K2O/planta). Empregou-se delineamento experimental em blocos casualizados, com cinco tratamentos e cinco repetições. No florescimento das plantas em cada ciclo, foram retiradas amostras foliares de duas plantas por parcela para serem analisados os teores de nitrogênio, fósforo, potássio, cálcio, magnésio, enxofre, boro, cobre, ferro, manganês e zinco. A maior parte dos macronutrientes presentes nas folhas não foi influenciada pelo incremento de doses de composto orgânico. No decorrer dos ciclos avaliados, os teores foliares de nitrogênio, fósforo, potássio, enxofre, boro, ferro e manganês diminuíram, enquanto o cálcio e o magnésio se acumularam nas plantas. Os teores de potássio estavam abaixo dos padrões para a cultura no Estado de São Paulo, em todos os anos avaliados, mesmo assim as plantas não apresentaram sintomas de deficiência ou queda de produção, inferindo-se que a faixa considerada como adequada para a cultivar pode ser inferior aos padrões atualmente adotados.

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To investigate the nutrition-related habits (NRH) of Brazilian adolescents and evaluate the associations with risk factors.Cross-sectional school-based was carried out among high school adolescents aged 14-18 years (n = 1,759) from public and private schools from two cities. The NRH were investigated by the weekly consumption of vegetables, fruit, sweet food and fried food. Risk factors investigated were: city, sex, age, socioeconomic status and nutritional status. In statistics, Poisson regression was used with robust variance adjustment.Data indicated low consumption of fruits and vegetables, 70.0 and 71.0%, respectively, and high consumption of sweets and fried food, 66.7 and 63%, respectively. Boys showed risk of inadequate intake of vegetables [prevalence ratios (PR) 1.10, 95% CI 1.01-1.16] and fruit (PR 1.09, 95% CI 1.01-1.16). Furthermore, adolescents who live in Maringa had greater likelihood of consuming vegetables and fruit (20 and 25%, respectively). However, they presented risk of inadequate consumption of sweets (PR 1.19, 95% CI 1.11-1.28) for adolescents who live in Presidente Prudente.We concluded that inadequate NRH show high prevalence among adolescents and indicate the need to employ educational strategies that promote the adoption of more healthy habits and behaviors.

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Hollandite-type manganese oxides are nanofibrous crystals with sub-nanometer open tunnels that provide a unique property for sensing applications. Sensor based on hollandite-type manganese oxide was investigated for amperometric detection of potassium. With an operating potential of +0.63 V versus SCE, potassium ions produce oxidation currents at the sensor, which can be exploited for quantitative determinations. The amperometric signals are linearly proportional to potassium ions concentration in the range 2.7 x 10(-4) to 9.1 x 10(-4) Mol l(-1) with a correlation coefficient of 0.9990. The construction and renewal are simple and inexpensive.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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In the work described by this paper, we studied the development of a selective potassium ion sensor constituted of a carbon paste electrode modified (CPEM) with a novel KSr(2)Nb(2)O(15). The material KSr(2)Nb(2)O(15) is an oxide with the tetragonal tungsten bronze structure (TTB) type are in forefront both in the area of research as well as in industrial applications. The sensor response to potassium ions was linear in the concentration range 1.26 x 10(-5) at 1.62 x 10(-3) mol L(-1) (E (mV) = 32.7 + 51.1 log [K(+)]). The sensor based KSr(2)Nb(2)O(15), of the TTB-type presented very good potentiometric response, with a slope of 51.1 mV/dec (at 25 degrees C) and detection limit for the potassium ions of 7.27 x 10(-5) mol.L(-1)

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Fencamfamine (FCF) is an indirect dopamine agent with effects similar to amphetamine and cocaine. In the present study, we investigate changes in Na,K-ATPase, cyclic AMP-dependent protein kinase (PKA) and nitric oxide synthase (NOS) activity and cyclic GMP levels in the nucleus accumbens (NAc) and striatum (ST) of animals acutely or repeatedly treated with FCF (3.5 mg/kg). Na,K-ATPase had a similar activity in control and repeatedly treated animals, but was reduced in the NAc of the acute group. This enzyme was reduced in the ST in acute and repeatedly treated animals, compared to the control group. Expression of the alpha(1,2,3)-Na,K-ATPase isoforms in the NAc and the ST was not altered in all groups studied. Acute FCF induced a significant increase in PKA activity in both the ST and the NAc. Repeatedly treated animals showed a higher increase in PKA activity in the NAc, but not in the ST, when compared to the acute group. There was also an increase in both NOS activity and cyclic GMP levels only in the NAc of FCF repeatedly treated animals compared to the acute and control groups. We suggest that chronic FCF treatment is linked to a modification in Na,K-ATPase activity through the PKA and NO-cyclic GMP pathway. (C) 2003 Elsevier Ltd. All rights reserved.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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O losartano potássico é um agente anti-hipertensivo não peptídico, que exerce sua ação por bloqueio específico dos receptores da angiotensina II. Este trabalho propôs a validação e aplicação de métodos analíticos orientados ao controle de qualidade de losartano potássico 50 mg na forma farmacêutica cápsula, utilizando a espectrofotometria direta e derivada de primeira ordem na região do UV. Baseado nas características espectrofotométricas de losartano potássico, um sinal a 205 nm do espectro de ordem zero e um sinal a 234 nm do espectro de primeira derivada foram adequados para a quantificação. Os resultados foram usados para comparar essas duas técnicas instrumentais. O coeficiente de correlação entre as respostas e as concentrações de losartano potássico na faixa de 3,0-7,0 mg L-1 e 6,0-14,0 mg L-1 para espectrofotometria direta e derivada de primeira ordem em solução aquosa, respectivamente, foi de (r) of 0,9999 para ambos os casos. Os métodos foram aplicados para quantificação de losartano potássico em cápsulas obtidas de farmácias de manipulação locais e demonstraram ser eficientes, fáceis de aplicar e de baixo custo. Além disso, não necessitam de reagentes poluentes e requerem equipamentos economicamente viáveis.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The circumventricular structures and the lateral hypothalamus (LH) have been shown to be important for the central action of angiotensin II (ANGII) on water and electrolyte regulation. Several anatomical findings have demonstrated neural connection between circumventricular structures and the LH, the present experiments were conducted to investigate the role of the alpha-adrenergic antagonists and agonistic injected into the LH on the water intake, sodium and potassium excretion elicited by injections of ANGII into the lateral ventricle (LV), the water intake was measured every 30 min over a period of 120 min. The sodium, potassium and urinary volume were measured over a period of 120 min in water-loaded rats. The injection of ANGII into the LV increased the water intake, which was reduced by previous injection of clonidine (an alpha-2-adrenergic agonist) into the LH. The injection of yohimbine (an alpha-2-adrenergic antagonist) and prazosin (an alpha-l-adrenergic antagonist) into the LH, which was done before injecting ANGII into the LV, also reduced the water intake induced by ANGII. The injection of ANGII into the LV reduced the sodium, potassium and urinary volume. Previous treatment with clonidine attenuated the action of ANGII in reducing the sodium, potassium and urinary volume, whereas previous treatment with yohimbine attenuated the effects of ANGII but with less intensity than that caused by clonidine. Previous treatment with prazosin increased the inhibitory effects of ANGII in those parameters. The injection of yohimbine and prazosin, which was done before the injection of clonidine, attenuated the effect of clonidine on the ANGII mechanism. The results of this study led us to postulate that when alpha-2-adrenergic receptors are blocked, the clonidine may act on the imidazoline receptors to produce its effects on the ANGII mechanism. We may also conclude that the LH is involved with circumventricular structures, which present excitatory and inhibitory mechanisms. Such mechanisms are responsible for regulating the renal excretion of sodium, potassium and water, (C) 2000 Elsevier B.V.

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Com o objetivo de avaliar o efeito da enxertia e do enriquecimento da água de irrigação com dióxido de carbono sobre o teor de N, P, K, Ca, Mg, S, Mn e Zn na parte aérea de plantas de pepino tipo japonês cultivados em ambiente protegido, foram conduzidos experimentos em duas épocas do ano. O delineamento experimental foi em blocos ao acaso com quatro tratamentos e quatro repetições. Os tratamentos foram plantas de pepino enxertadas e não enxertadas, irrigadas com água comum ou enriquecida com CO2, em uma concentração de 1 no primeiro semestre e 0,25 no segundo semestre. No final do ciclo da cultura, o CO2, influenciou unicamente no primeiro semestre os teores de K, Ca, Mg, S e Zn; enquanto o teor de N só alterou no segundo semestre. Não houve padrão de resposta consistente da enxertia sobre os teores de N, P, Mg e Zn; porém, plantas enxertadas apresentam maior teor de K e menor teor de Mg, S e Ca na sua parte aérea, ao final do ciclo da cultura, podendo estar relacionado com os sintomas de deficiências nutricionais observados em plantas de pepino enxertadas.

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Background: The AIN-93 diet was proposed by the American Institute of Nutrition with the objective of standardising studies in experimental nutrition. Our objective was to analyze the effects of AIN-93 diet after myocardial infarction in rats.Methods: Post weaning, the animals were divided into two groups: control (C, n=62), fed the standard diet of our laboratory (Labina); AIN-93 Group (n=70), fed the AIN-93 diet. Achieving 250 g, the animals were subjected to myocardial infarction.Results: Early mortality was increased in AIN-93 animals, associated with lower serum levels of calcium, magnesium, potassium, sodium, and phosphorus. on the other hand, after 90 days, AIN-93 showed smaller normalized left ventricular dimensions. The caloric and carbohydrate intake was smaller, but the fat intake was higher in AIN-93 rats. AIN-93 group also showed increased levels of beta-hydroxyacylcoenzyme A dehydrogenase and citrate synthase. In addition, serum levels of insulin and cardiac levels of malondialdehyde, metalloproteinases-2 and -9, and TNF-alpha and IFN-gamma were decreased in the AIN-93 group.Conclusion: AIN-93 diet increased early mortality, while attenuated the chronic remodeling process after experimental coronary occlusion. Therefore, this diet has biological effects and should be use with attention in this model. (C) 2010 Elsevier B.V. All rights reserved.