Implementation of Time Temperature Indicators to Improve Temperature Monitoring and Support Dynamic Shelf Life in Meat Supply Chains.

Based on the well-investigated OnVu™ TTI kinetics, models were developed to adjust the label to different food products and predict the discolouration process under dynamic temperature conditions. After the successful validation under laboratory conditions, the applicability of the time temperature indicator (TTI) as shelf life indicator was tested in a national poultry chain. The TTI accurately reflected the temperature fluctuations occurring under real chain conditions.

Measuring Cumulative Exposure to Oxygen with a Diphenylphosphine-Alkyl Naphthaleneimide Luminescence Turn-On Dyad.

2-(2-Diphenylphosphanylethyl)benzo[de]isoquinoline-1,3-dione is a poorly luminescent, photoinduced-electron-transfer (PET) dyad, NI-(Ph)2 P:, in which the luminescence of its naphthaleneimide (NI) part is quenched by the lone-pair electrons of the phosphorus atom of the (Ph)2 P: group. Photoinduced oxidation of (Ph)2 P: to (Ph)2 P=O by molecular oxygen regenerates the luminescence of the NI group, because the oxidized form (Ph)2 P=O does not serve as a quencher to the NI system. The oxidation of (Ph)2 P: is thermally inaccessible.

Spectral measurements of the emission from highly scattering gain media.

The spectral properties of the emission of a colloidal suspension of titanium dioxide particles in Rhodamine 640 perchlorate were studied systematically. The particle density rho, the dye concentration c, and the energy of the pump pulse were varied over several orders of magnitude; the dependence of the spectra on these three parameters is discussed. We discovered a strong correlation between the particle density and the dye concentration.

Zinc-tetrabenzoporphyrine-doped poly(methyl methacrylate): a new photochromic recording medium.

A photochromic reaction in Zn-tetrabenzoporphyrine-doped poly(methyl methacrylate) was investigated at room temperature. A one-quantum thermoreversible photoreaction could be initiated in the sample with 633-nm He-Ne laser irradiation. The photoreaction quantum yield depended strongly on the concentration of an additional electron acceptor.

Doped rare gas solids as model systems for chromophore-matrix interactions.

Molecular electronic states are extremely sensitive to changes in their environment. Therefore, by inserting probe molecules into a host material and monitoring the ensuing changes in the widths and spectral positions of the electronic absorption bands, interactions of probe and host molecules can be studied. A statistical mechanical model used to analyze these data can also be employed to extract from pressure-induced changes of the band shape information about the local environment of the probe molecule.

Electro-optic Pockels and Kerr effects for the determination of χ((2))and χ((3)): thin films of side-chain polymers containing dimethylaminonitrostilbene and of the polydiacetylene poly-(butoxycarbonylmethyleneurethane).

A simple reflection method that is based on ellipsometry and the electro-optic Pockels and Kerr effects is adapted for the determination of the electro-optic susceptibilities χ((2))(-ω; 0,ω) and χ((3))(-χ; 0, 0, ω). Measurements were made on materials that consist of centrosymmetric molecules like the polydiacetylene poly-(butoxycarbonylmethyleneurethane) (poly-4BCMU) and on a noncentrosymmetric poled sidechain polymer that contains dimethylaminonitrostilbene (ANS). The results are compared with those acquired by other methods (e.