Evaluation of Modern Approaches for the Assessment of Dietary Carotenoids as Markers for Fruit and Vegetable Consumption.

The assessment of dietary carotenoids via blood measurements has been widely used as a marker for fruit and vegetable consumption. In the present study, modern, non-invasive approaches to assess dietary carotenoids, such as skin measurements and an app-based short dietary record (ASDR), were compared with conventional methods such as plasma status and handwritten 3-day dietary records. In an 8-week observational study, 21 healthy participants aged 50-65 years recorded their daily consumption of carotenoid-rich fruits and vegetables via a specially developed ASDR.

Vibrational relaxation of carbon dioxide in water.

The dynamics of vibrational relaxation of carbon dioxide in water has been studied using femtosecond mid-infrared pump-probe spectroscopy with excitation of the anti-symmetric stretching (ν) fundamental state of the solute. The relaxation dynamics were recorded at a constant pressure of 500 bars and in the temperature range between 300 and 600 K, thereby covering the liquid-to-near-critical region of the solvent. The excited state of the ν-mode is deactivated in two competing pathways: (i) direct relaxation to the ground state with resonant transfer of the excess vibrational energy into the bending-librational continuum of the water solvent and (ii) relaxation to the bending fundamental state with transfer into the intramolecular bending mode of HO.

Femtosecond 2DIR spectroscopy of the nitrile stretching vibration of thiocyanate anions in liquid-to-supercritical heavy water. Spectral diffusion and libration-induced hydrogen-bond dynamics.

Femtosecond two-dimensional infrared (2DIR) spectroscopy was carried out to study the dynamics of vibrational spectral diffusion of the nitrile stretching vibration of thiocyanate anions (S-C≡N(-)) dissolved in liquid-to-supercritical heavy water (D2O). The 2DIR line shapes were used to extract through a nodal slope analysis quantitative information about the correlation function for temporal fluctuations of the CN-stretching frequency. The inverse nodal slope could be fitted phenomenologically by a simple double-exponential decay whose predominant component had a time constant ranging between 300 fs and 1 ps depending on the temperature.

Vibrational Energy Relaxation of Thiocyanate Ions in Liquid-to-Supercritical Light and Heavy Water. A Fermi's Golden Rule Analysis.

The vibrational relaxation dynamics following an ultrafast nitrile stretching (ν3) excitation of thiocyanate anions dissolved in light and heavy water have been studied over a wide temperature and density range corresponding to the aqueous liquid up to the supercritical phase. In both solvents, the relaxation of the ν3 = 1 state of the anion leads to a direct recovery of the vibrational ground state and involves the resonant transfer of the excess vibrational energy onto the solvent. In light water, the energy-accepting states are provided by the bending-librational combination band (νb + νL), while in heavy water, the relaxation is thermally assisted by virtual acceptor states derived from the stretching-librational/restricted translational hot band (νS - νL,T).