The addition of water is used to past by internal post-curing of hardening cement. Hydration and curing of cementitious are widely identified by non-destructive H nuclear magnetic resonance (NMR) measurements of transverse relaxation time and self-diffusion. However, those non-destructive analytical methodologies do not give a truly chemical characterization of the cement matrix during the hydration and curing process.
View Article and Find Full Text PDFIn this review, some results of the experimental activity carried out by the authors on advanced composite materials for space applications are reported. Composites are widely employed in the aerospace industry thanks to their lightweight and advanced thermo-mechanical and electrical properties. A critical issue to tackle using engineered materials for space activities is providing two or more specific functionalities by means of single items/components.
View Article and Find Full Text PDFSeveral nutraceutical preparations containing proteins, amino acids and other small molecules are nowadays present on the market. In this work we propose NMR spectroscopy such as (1)H NMR, (1)H-(1)H TOCSY and DOSY for their constituents characterization, identification and profiling, comparing these results with those obtained by electrophoretic technique such as SDS-PAGE. The (1)H NMR spectroscopy was applied for measurements of the amino acids and other small compounds added from the manufacturer.
View Article and Find Full Text PDFRaman spectroscopy was used to study the NaCl aqueous solutions around the solid-liquid phase transition. Special attention was devoted to the modification induced by the salt on the OH stretching band of water. Investigations were carried out in the temperature range between -21 and 10 degrees C, for concentrations from 0 to 200 g/L.
View Article and Find Full Text PDFWe propose a new optical sensor to characterize the solid-liquid phase transition in salted solutions. The probe mainly consists of a Raman spectrometer that extracts the vibrational properties from the light scattered by the salty medium. The spectrum of the O-H stretching band was shown to be strongly affected by the introduction of NaCl and the temperature change as well.
View Article and Find Full Text PDFDietary selenium, vitamin B6 and fatty acids modulate both tissue acyl composition by regulating polyunsaturated fatty acid metabolism and antioxidant defences by influencing glutathione peroxidase activity. Alteration in the intake of one of them could therefore lead to different results depending on the intake of the others. To clarify this complex relationship, in the present study we have evaluated the modifications occurring in fatty acid composition and glutathione peroxidase activity in total liver and liver microsomes of rats fed diets containing the same amount of selenium, but different vitamin B6 content and fatty acid composition.
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