Differentiation among dairy products by combination of fast field cycling NMR relaxometry data and chemometrics

A set of commercial milk and Sicilian cheeses was analysed by a combination of fast field cycling (FFC) nuclear magnetic resonance (NMR) relaxometry and chemometrics. The NMR dispersion (NMRD) curves were successfully analysed with a mathematical model applied on Parmigiano–Reggiano (PR) cheese. Regression parameters were led back to the molecular components of cheeses (water trapped in casein micelles, proteins and fats) and milk samples (water belonging to hydration shells around dispersed colloidal particles of different sizes and bulk water). The application of chemometric analysis on relaxometric data enabled differentiating milk from cheeses and revealing differences within the two sample groups of either cheeses or milk samples. Marked differences among cheeses were evidenced by statistical analysis of the sole quadrupolar peaks parameters, suggesting that these contain information on the nature of the milk used during cheese production. Hence, combination of FFC NMR and chemometrics represents a powerful tool to investigate alterations in dairy products.     

Kan Extensions are Partial Colimits

Applied Categorical Structures - One way of interpreting a left Kan extension is as taking a kind of “partial colimit”, whereby one replaces parts of a diagram by their colimits. We...     

HPLC and NMR analysis of the phenyl-ethanoid glycosides pattern of Verbascum thapsus L. cultivated in the Etnean area

In this work the HPLC and NMR analysis of the phenyl-ethanoid glycosides (PhGs) pattern of a cultivated exemplar of Verbascum thapsus L. (Scrophulariaceae) from the Etnean area (Sicily, Italy) was performed in order to verify their possible presence. Wild V. thapsus is well-known in ethnopharmacology due to the several beneficial effects that it is able to exert and which are primarily due to these compounds. So, it’s extremely important that also cultivated exemplars of this species biosynthesize them in order to maintain their pharmacological properties. This study revealed the presence of seven PhGs in an unusual novel pattern. Thus, this exemplar is a very good potential source of this class of natural products and may be employed for several beneficial ethnopharmacological purposes.     

Evaluation of different light-curing lamps

The aim of this study has been to evaluate light-curing composites polymerization quality carried out by halogen and new-diode lamps through the thermal analysis (TG?CDTA). Samples have been polymerized at 3?C20?C40?C60?s by halogen lamp and 1?C3?C6?C9?s by new-diode lamp. The TG/DTA analysis shows that different light-curing times affect the degree of conversion of the composite, since by increasing the curing time the quantity of the monomer that has not reacted (residual) decreases. The new-diode lamp, according to the manufacturer, can cure composite restorations in few seconds; but at the conditions used in this study, the samples cured by the halogen lamp at the standard times of exposure, compared to the samples cured in few seconds by the new-diode lamp, show a lower mass loss.     

An unified formulation of strong non-local elasticity with fractional order calculus

Meccanica - The research of a formulation to model non-local interactions in the mechanical behavior of matter is currently an open problem. In this context, a strong non-local formulation based on...     

Oligopeptide Helical Conformations Control Gold Nanoparticle Cross-Linking

Peptide sequences functionalized with primary amines at the N- and C-terminus are able to induce the aggregation of gold nanoparticles in ethanol as a consequence of their folding into a helical conformation. Random coil peptides are unable to induce such an aggregation process. Aggregation can be monitored spectrophotometrically by following the shift of the surface plasmon resonance (SPR) band of the nanoparticles and is confirmed by transmission electron microscopy and dynamic light scattering analyses. Partial denaturation of the peptides results in diminished cross-linking ability. The helicity parameter θ₂₂₂/θ₂₀₈ correlates fairly well with the shift of the SPR band to longer wavelengths, supporting the relationship between the amount of helical content of a peptide sequence and its ability to induce aggregation.     

A Supramolecular Palladium Catalyst Displaying Substrate Selectivity by Remote Control

Inspired by enzymes such as cytochrome P-450, the study of the reactivity of metalloporphyrins continues to attract major interest in the field of homogeneous catalysis. However, little is known about benefitting from the substrate-recognition properties of porphyrins containing additional, catalytically relevant active sites. Herein, such an approach is introduced by using supramolecular ligands derived from metalloporphyrins customized with rigid, palladium-coordinating nitrile groups. According to different studies (NMR and UV/Vis spectroscopy, XRD, control experiments), the supramolecular ligands are able to accommodate pyridine derivatives as substrates inside the porphyrin pocket while the reactivity occurs at the peripheral side. By simply tuning a remote metal center, different binding events result in different catalyst reactivity, and this enzyme-like feature leads to high degrees of substrate selectivity in representative palladium-catalyzed Suzuki–Miyaura reactions.