Effects of selenium addition on minimally processed leafy vegetables grown in a floating system

BACKGROUND: In recent years the consumption ofminimally processed leafy vegetables has been increasing. At the same time food quality and its effects on human health have become crucial issues. Since selenium (Se) is an important microelement due to its ability to defend human organisms against free radicals, we investigated the effects of Se on chicory and lettuce production, and assessed the feasibility of a floating system as a method of producing Se-enriched vegetables. RESULTS: The addition of 0.5 and 1.0mg Se L−1 to the nutrient solution resulted in an increase in the selenium concentration in the leaves, which had a positive effect on the plant yield. Selenium was generally effective in decreasing the production of ethylene and phenylalanine ammonia lyase (PAL) activity, even though a seasonal effect seemed to be present, consequently improving the quality of leafy vegetables and the shelf life in both species. The amount of Se accumulated in plants grown in the nutrient solution containing 0.5 mgSe kg−1 could provide the rational Se intake for human nutrition in accordance with the recommended dietary allowance (RDA) guidelines. CONCLUSIONS: The addition of Se in a nutrient solution can be a useful system for providing enriched leafy vegetables. The floating system can be used to modulate the availability of Se in nutrient solutions and to grow vegetables with the optimal Se content for human healt

Specific ion effects on the electrokinetic properties of iron oxide nanoparticles: Experiments and simulations

We report experimental and simulation studies on ion specificity in aqueous colloidal suspensions of positively charged, bare magnetite nanoparticles. Magnetite has the largest saturation magnetization among iron oxides and relatively low toxicity, which explain why it has been used in multiple biomedical applications. Bare magnetite is hydrophilic and the sign of the surface charge can be changed by adjusting the pH, its isoelectric point being in the vicinity of pH = 7. Electrophoretic mobility of our nanoparticles in the presence of increasing concentrations of different anions showed that anions regarded as kosmotropic are more efficient in decreasing, and even reversing, the mobility of the particles. If the anions were ordered according to the extent to which they reduced the particle mobility, a classical Hofmeister series was obtained with the exception of thiocyanate, whose position was altered. Monte Carlo simulations were used to predict the diffuse potential of magnetite in the presence of the same anions. The simulations took into account the ion volume, and the electrostatic and dispersion forces among the ions and between the ions and the solid surface. Even though no fitting parameters were introduced and all input data were estimated using Lifshitz theory of van der Waals forces or obtained from the literature, the predicted diffusion potentials of different anions followed the same order as the mobility curves. The results suggest that ionic polarizabilities and ion sizes are to a great extent responsible for the specific ion effects on the electrokinetic potential of iron oxide particles.The authors thank the financial support from the following institutions: (i) ‘Ministerio de Economía y Competitividad, Plan Nacional de Investigación, Desarrollo e Innovación Tecnológica (I + D + i)’, Projects MAT2013-44429-R, MAT2012-36270-C04-04 and -02. (ii) ‘Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía’, Projects P09-FQM-4698, P10-FQM-5977, and P11-FQM-7074. (iii) European Regional Development Fund (ERDF)

Phosphorus characterization in feces from broiler chicks fed low-phytate barley diets

The inclusion of low phytate grains in poultry diets can reduce the phosphorus (P) content of poultry feces, but their influence on fecal P composition is not well established. To assess this, 100 male broiler chicks (21 days old) were fed dietary treatments based on either a wild-type barley or one of three low phytate mutant barleys with 59, 62 and 99% reductions in phytate P, compared with the normal barley diet. The birds were housed in raised-floor battery cages with mesh grate floors above fecal collection trays with five birds per pen and five pens per treatment. The birds were fed for 9 days and feces were collected twice a day during the last 2 days of the experiment. Total P concentrations were 14-24% lower in feces from birds fed low phytate barley diets compared with those fed the normal barley diet. Phosphorus digestibility increased (P < 0.05) as phytate in the barley diet decreased. Phosphate was the major P fraction in the feces (69-75% extracted P) regardless of the type of barley fed. Phytate constituted only 3-12% of the P in the feces, indicating its hydrolysis in the bird. Overall, these results suggest that feeding low-phytate barley diets can reduce P concentrations in poultry feces without causing significant changes in P composition

Historical changes in sediments of Pyramid Lake, Nevada, USA: consequences of changes in the water balance of a terminal desert lake

Sediment cores from the shallow and deep basins of Pyramid Lake, Nevada, revealed variations in composition with depth reflecting changes in lake level, river inflow, and lake productivity. Recent sediments from the period of historical record indicate: (1) CaCO 3 and organic content of sediment in the shallow basin decrease at lower lake level, (2) CaCO 3 content of deep basin sediments increases when lake level decreases rapidly, and (3) the inorganic P content of sediments increases with decreasing lake volume. Variations in sediment composition also indicate several periods for which productivity in Pyramid Lake may have been elevated over the past 1000 years. Our data provide strong evidence for increased productivity during the first half of the 20th Century, although the typical pattern for cultural eutrophication was not observed. The organic content of sediments also suggests periods of increased productivity in the lake prior to the discovery and development of the region by white settlers. Indeed, a broad peak in organic fractions during the 1800's originates as an increase starting around 1600. However, periods of changing organic content of sediments also correspond to periods when inflow to the lake was probably at extremes (e.g. drought or flood) indicating that fluctuations in river inflow may be an important factor affecting sediment composition in Pyramid Lake.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43069/1/10933_2004_Article_BF00678089.pd

Evaluation of nurse assessment of a patient's weight status at the time of hospital admission

Includes bibliographical references