1,721,048 research outputs found
ZnSe/GaAs(001) heterostructures with defected interfaces: structural, thermodynamic and electronic properties
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Composition and strain dependence of band offsets at metamorphic In(x)Ga(1-x)As/In(y)Al(1-y)As heterostructures
No full textRevisiting Mn-doped Ge using the Heyd-Scuseria-Ernzerhof hybrid functional RID E-7702-2010
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Structural, electronic and ferroelectric properties of croconic acid crystal: A DFT study
No full textThe recent discovery of high polarization at room temperature in croconic acid crystals as large as 21 mu C cm(-2) [Horiuchi et al., Nature, 2010, 463, 789] has lead to renewed interest in organic ferroelectrics, a promising class of materials for future electronic devices. We present here an extended ab initio study of this molecular crystal, using different approximations for the exchange-correlation functionals, ranging from local and semi-local types to more sophisticated hybrid functionals and van der Waals corrected functionals. Furthermore, by using distortion mode analysis, we focus on the different contributions to the polarization and on their microscopic origins
Chemometric differentiation of PDO and non-PDO Italian and foreign hard cheeses using 1H NMR spectroscopy
No full textThe gargantuan sizes of food markets represents a constant challenge to control agencies. With the Protected Designation of Origin (PDO) in force, and with the ever-increasing diversity of food products, such as dairy products (in particular, cheese) robust and reliable analytical methods are required.
Of many analytical techniques used for this purpose, Nuclear Magnetic Resonance (NMR) spectroscopy, specifically that utilizing 1H nuclei has been long been used for analysis, identification and authentication of various food products, such as wine, juice, coffee, edible oils and others.
We have studied a selection of Grana Padano, Parmigiana Reggiano and foreign competitor cheeses by applying 1H NMR spectroscopic analysis to aqueous extracts and also additionally 13C NMR to lipid extracts. After the advanced data post-processing such as dynamic alignment and optimized bucketing, different multivariate statistics approaches such as PCA and PLS-DA were utilized.
We addressed such group features as cheese variety, geographical origin, maturation time and year of production, as well as drawbacks and advantages of each of the approache
1H NMR profiling and chemometric analysis for ripening and production characterization of Grana Padano cheese
Full text linkGrana Padano (GP) cheese is a renowned PDO Italian cheese whose nutritional characteristics and market price are influenced by the ripening stage. In this work, it was demonstrated that the combined use of untargeted 1H NMR profiling and chemometric analysis can be used as a powerful tool to quantitatively characterize GP ripening and production, focusing on both aqueous and lipid fractions. An initial exploratory analysis revealed substantial variations in the aqueous fraction attributable to aging time, year and season of production. Multivariate analysis was adopted to show these differences, mainly attributable to amino acids. In contrast, the lipid fraction analysis highlighted the impact of production season on fatty acid unsaturation, influenced by feed variations. As regards the production process, this study focuses on the variations induced by bactofugation. In this respect, the aqueous fraction was found to be extensively influenced by this centrifugation step, affecting compounds crucial to organoleptic characteristic
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