Microwave-assisted catalysis by iron oxide nanoparticles on MCM-41: Effect of the support morphology

Catalytically active heterogeneous catalysts have been prepared via microwave deposition of iron oxide nanoparticles (0.5–1.2 wt%) on MCM-41 type silica materials with different morphologies (particles, helical and spheres). This methodology leads to iron oxide nanoparticles composed by a mixture of FeO and Fe2O3 species, being the Fe(II)/Fe(III) peak ratio near to 1.11 by XPS. DRUV spectroscopy indicates the presence of tetrahedral coordinated Fe3+ in the silica framework of the three catalysts as well as some extraframework iron species in the catalysts with particle and sphere-like morphologies. The loading of the nanoparticles does neither affect the mesopore arrangement nor the textural properties of the silica supports, as indicated by SAXS and nitrogen adsorption/desorption isotherms. A detailed investigation of the morphology of the supports in various microwave-assisted catalyzed processes shows that helical mesostructures provide optimum catalytic activities and improved reusabilities in the microwave-assisted redox (selective oxidation of benzyl alcohol) catalyzed process probably due to a combination of lower particle size and higher acidity in comparison with the supports with particle and sphere morphology.

Effect of commercial amino acids on iron nutrition of tomato plants grown under lime-induced iron deficiency

The objective of this work was to study the effect of root and foliar application of two commercial products containing amino acids from plant and animal origin on iron (Fe) nutrition of tomato seedlings cultivated in two nutrient media: lime and normal nutrient solutions. In the foliar-application experiment, each product was sprayed with 0.5 and 0.7 mL L–1 2, 7, 12, and 17 d after transplanting. In the root application experiment, 0.1 and 0.2 mL L–1 of amino acids products were added to the nutrient solutions. In both experiments, untreated control plants were included as well. Foliar and root application of the product containing amino acids from animal origin caused severe plant-growth depression and nonpositive effects on Fe nutrition were found. In contrast, the application of the product from plant origin stimulated plant growth. Furthermore, significantly enhanced root and leaf FeIII-chelate reductase activity, chlorophyll concentration, leaf Fe concentration, and FeII : Fe ratio were found in tomato seedlings treated with the product from plant origin, especially when the amino acids were directly applied to the roots. These effects were more evident in plants developed under lime-induced Fe deficiency. The positive results on Fe uptake may be related to the action of glutamic acid, the most abundant amino acid in the formulation of the product from plant origin.

The effect of smoking on visceral fat accumulation in Czech men and women

Many studies indicate that smoking is one of risk factors influencing the accumulation of visceral fat (VFA). The mechanism by which smoking contributes to the accumulation of visceral fat is not yet fully understood, but it is assumed that smoking increases the level of plasma cortisol, causes imbalance between male and female sex hormones in women, and decreases testosterone levels in men (Chiolero et al., 2008). The objection of this study was to evaluate the effect of smoking on the accumulation of VFA in the population of the Czech Republic. The research included 1,412 individuals of both genders divided into categories of smokers vs nonsmokers and physically active vs. physically inactive. VFA was measured by the device InBody 720 and information about physical activity and smoking was collected via a questionnaire. We supposed that smokers would have a higher percentage of VFA than non-smokers. The results showed that smokers had a higher amount of VFA, but the difference was not statistically significant. In contrast, statistically significant differences were found in the waist-to-hip ratio (WHR) and total % body fat. Physically active individuals had a much more favourable results than physically inactive individuals. Remarkably, the amount of VFA, WHR and % body fat tended to be smaller in smoking men than in non-smoking men, but higher in smoking women than in non-smoking women.

Heavy metal release due to aging effect during zero valent iron nanoparticles remediation

Zero valent iron nanoparticles (nZVI) represent a promising agent for environmental remediation. Nevertheless, their application presents some limitations regarding their rapid oxidation and aggregation in the media. The aim of this study was to determine the effect that nZVI aging has in heavy metal remediation in water. Contaminants studied were Zn, Cd, Ni, Cu and Cr, which are typical elements found in ground and wastewater. Results show a high contaminant removal capacity by the nZVI in the first 2 h of reaction. Nevertheless, for longer reaction times, some of the metal ions that had already been adsorbed in the nZVI were delivered to the water. Cd and Ni show the maximum delivery percentages (65 and 27% respectively after 21 days of contact time). The starting delivery time was shortened when applying lower nZVI amounts. No re-dissolution of Cr was observed in any circumstance because it was the only element incorporated into the nanoparticles core, as TEM images showed. Contaminant release from nZVI is probably due to nanoparticles oxidation caused by aging, which produced a pH decrease and nZVI surface crystallization.