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Inclusion complexes of cyclodextrins with nonpolar drugs are a topic of current interest in pharmaceutical science, because they increase the aqueous solubility, chemical stability and bioavailability of poorly water-soluble drugs. By means of elastic incoherent neutron scattering (EINS) technique on the backscattering spectrometer IN13, we measured, in the 150−340 K temperature range, the mean square displacements (MSD) of hydrogen atoms derived from elastic spectra of inclusion complex of β-cyclodextrin (β-CyD) with genistein (Gen), a phytoestrogen of great interest for its antioxidant, anticarcinogenic and antiosteoporotic activities. The mobility of the complex has been compared with the single components and the physical mixture. The elastic intensity has been interpreted in terms of the double-well model in the whole temperature range. In the case of Gen, a mainly vibrational dynamics is revealed, while for the other samples, the elastic intensity becomes non-Gaussian above a temperature Td≅ 220−230 K. This dynamical activation, which is represented by an Arrhenius trend, seems to be promoted by the crystallization water molecules. The dynamics of the Gen/β-CyD inclusion complex is restricted with respect to the physical mixture, due to the action of specific “host−guest” interactions upon complexation. Finally, the dynamical response of our systems to temperature is put in relationship with their thermal stability. [ABSTRACT FROM AUTHOR]

By pulsed field gradient nuclear magnetic resonance measurements, we investigated the translational diffusion of water confined in the 200 Å diameter pores of a sol−gel silica glass. The experiments, performed as a function of the hydration level, showed an enhancement of the self-diffusion coefficient when the water content corresponds to one or fewer monolayers. An explanation for this occurrence has been given in terms of a two-phase process involving a fast molecular exchange between the liquid and the vapor phase. Moreover, in partially filled pores, the surface water diffusion coefficient was measured, and was 4 times lower than the diffusion of liquid confined water in saturated spaces. [ABSTRACT FROM AUTHOR]

The vibrational dynamics of water molecules encapsulated in synthetic Na-A and Mg-exchanged A zeolites were studied versus temperature by inelastic neutron scattering (INS) measurements (30−1200 cm-1) as a function of the induced ion-exchange percentage by using the indirect geometry tof spectrometer TOSCA at the ISIS pulse neutron facility (RAL, UK). The experimental INS spectra were compared with those of ice Ih to characterize the structural changes induced by confinement on the H2O hydrogen-bonded network. We observed, after increasing the Mg2+ content, a tendency of water molecules to restore the bulklike arrangements together with more hindered dynamics. These results are confirmed by the analysis of the evaluated one-phonon amplitude-weighted proton vibrational density of states aimed, in particular, to follow the evolution of the water molecules librational mode region. [ABSTRACT FROM AUTHOR]

In the present study we carried out an extensive non-destructive and micro-destructive surface investigation on ancient decorated Sicilian samples of cultural interest, using a combination of different spectroscopic methods. In particular, the elemental composition, obtained by a handheld XRF analyser, acted as a valuable guideline for subsequent targeted sampling actions, thus minimizing the sampling damage. Hence, some questions not answered by XRF measurements (identification of some pigments, preparation layers, etc.) were subsequently resolved using Scanning Electron Microscopy coupled with Energy-Dispersive Spectrometry (SEM-EDS) and Fourier Transform Infrared absorbance spectroscopy (FT-IR). This multi-technique approach allowed us to provide useful information to establish the pigments and the production technique used by the craftsmen. [ABSTRACT FROM AUTHOR]

A non-invasive time-of-flight neutron diffraction (TOF-ND) analysis has been performed on archaeological pottery fragments from the excavation sites in the “Strait of Messina” area (Sicily, Southern Italy). The revealed quantitative information on the mineralogical composition have been compared, in the case of two samples representative of coarse and fine grained pottery, with the weight fractions of the crystalline phases as obtained from X-ray diffraction on powders (XRPD), for different amounts of extracted powder. From the results, the consistency of these micro-destructive and non-invasive approaches has been checked. This research may contribute to better define the most efficient sampling and analytical method for the determination of mineralogical composition on ceramics different in structure and composition. [ABSTRACT FROM AUTHOR]