Effect of dietary vitamin E supplementation on lipid and colour stability of chicken thigh meat

Lipid and myoglobin oxidation are major causes of meat quality deterioration during storage of fresh chicken meat. Our objective is to determine the effects of dietary -tocopherol supplementation on lipid and colour stability of fresh chicken thigh meat exposed in a supermarket shopwindow or stored in a refrigerator. Chickens were fed with diets containing 25 (control), 100, 200 or 300 mg vitamin E/kg of food for 20 days before slaughtering. Peroxide value (PV) and oxidation products specific extinctions (K232 and K270), chosen as markers for oxidative deterioration of lipids, were lower in chicken meat from animals supplemented with 200 or 300 mg vitamin E than that of the control meat upon storage during 5 days in a shopwindow (p < 0.01) or 9 days in a refrigerator (p < 0.01). Vitamin E dietary supplementation (200 mg vitamin E/kg of food) reduced oxidation products formation in fresh thighs meat but had no significant impact on colour analysed by value redness (a*) measurements

Temperature-Dependent Polarized Raman Spectra of CaFe2O4

The Raman spectra of CaFe2O4 were measured with several exact scattering configurations between 20 and 520K and the symmetry of all observed Raman lines was determined. The Ag and B2g lines were assigned to definite phonon modes by comparison to the results of lattice dynamical calculations. No anomaly of phonon parameters was observed near the magnetic ordering temperature TN = 160K.Comment: 4 pages, 1 table, 4 figure

Pyrene bisiminopyridine ligand and its zinc complex

The synthesis of a pyrene bisiminopyridine ligand L was successfully accomplished by condensation between 1-aminopyrene and 2,6-pyridinecarboxaldehyde. The complexation of L with zinc triflate afforded a neutral metal complex formulated as [Zn(H2O)LCF3SO3)2].2Et2O. In the complex, the ligand is coordinated to zinc(II) through its three nitrogen atoms which form a distorted octahedral environment together with three oxygen atoms, two from the triflate anions and one from aqua ligand. Both compounds have been characterized using NMR, elemental analysis, mass spectrometry, electronic absorption (UV-Vis) and infrared. Luminescence properties of these compounds show an emission maxima at 412 nm, indicating a pyrene monomer emission

Modulation des propriétés ONL de ligands azobenzéniques par coordination de cations métalliques

National audienc

Evaluation by MALDI-TOF MS and PCA of the diversity of biosurfactants and their producing bacteria, as adaption to weathered oil components

Indigenous Qatari bacterial strains were isolated from highly weathered oil-contaminated sites, identified, and differentiated based on their protein profiles using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Their diversity was demonstrated by the principal component analysis (PCA) analysis and establishment of a proteodendogram. Both were based on the protein profile of each strain. Interestingly, this approach also showed diversity within the same subspecies. This high diversity is reflected in the emulsification and solubilization activities of their extracellular biosurfactants. The highest emulsification activity (42.1 ± 2.11 AU/mL) was obtained with a strain of Lysinibacillus fusiformis (SA4) after one week of growth in the minimum salt medium in which diesel (5%) is the sole carbon source, while the highest solubilization activity (9.47% ± 0.47%) was produced by the strain Bacillus subtilis (SA6). The functional diversity of the biosurfactants was demonstrated by PCA analysis which allowed their further clustering based on the Fourier-transform infrared spectroscopy (FTIR) analysis. These findings clearly showed that two types of adaptations occur with hydrocarbons degrading bacteria in the weathered-oily soils, one related to the bacterial cell composition maintaining the biosurfactants composition and one to the biosurfactants, which are the primary tool employed by the cell to interact with the weathered oil. This finding would shed light on the potential and strategies of applications for the bioremediation of highly weathered oil-contaminated soils.Scopu

Specific heat and magnetocaloric effect in Pr1-xAgxMnO3 manganites

The magnetocaloric effect in alternating magnetic fields has been investigated in Pr1-xAgxMnO3 manganites with x=0.05-0.25. The stepwise reversal of the sign of the magnetocaloric effect has been revealed in a weakly doped sample (x=0.05) at low temperatures (~80 K). This reversal is attributed to the coexistence of the ferromagnetic and canted antiferromagnetic phases with different critical temperatures.Comment: 4 pages, 4 figure

Clustering dynamics of Lagrangian tracers in free-surface flows

We study the formation of clusters of passive Lagrangian tracers in a non-smooth turbulent flow in a flat free-slip surface as a model for particle dynamics on free surfaces. Single particle and pair dispersion show different behavior for short and large times: on short times particles cluster exponentially rapidly until patches of the size of the divergence correlation length are depleted; on larger times the pair dispersion is dominated by almost ballistic hopping between clusters. We also find that the distribution of particle density is close to algebraic and can trace this back to the exponential distribution of the divergence field of the surface flow.Comment: 5 pages, 5 Postscript figure