Use of radiation-induced alkanes and alkenes to detect irradiated food containing lipids

To detect irradiated foodstuffs, we used the Nawar relation between lipid structure and radiolysis compounds, such as alkanes and alkenes. We first applied this method to sunflower, olive and peanut oils. Alkanes and alkenes were analyzed by gas chromatography with a head-space system for desorption and concentration of the volatile compounds. The detection limit, obtained both by estimation of the chromatogram area and by a blind trial, is better than 0.15 kGy. The continuity of detection with storage time was also studied. We have compared these results with those obtained by thermolysis: the same method can be used to detect ionized vegetable oils, even if they have been heated. In a second step, we studied three possible commercial situations—the irradiation of avocado-pears, fresh pilchards and poultry meat. Although we can use this lipid method to identify irradiated avocado-pears (for doses above 0.5 kGy) and poultry meat, it is impossible to apply it to fresh pilchards because numerous volatile compounds are already present before irradiation.     

Dietary proteins modulate the effects of fish oil on triglyceridemia in the rat

Sprague-Dawley rats were fed purified diets varying in both protein (20%) and lipid (11%) content for 28 d to verify the independent and interactive effects of dietary proteins and lipids on serum and hepatic lipids, and on tissue lipoprotein lipase (LPL) activity in both fasted and postprandial states. These diets consisted of either casein-menhaden oil, casein-coconut oil, soy protein-menhaden oil (SPMO), soy protein-coconut oil, cod protein-menhaden oil, or cod protein-coconut oil. A randomized 3×2 factorial design was used. A significant protein-lipid interaction was seen on serum triglyceride levels: menhaden oil, compared with coconut oil, induced a decrease in serum triglyceride levels when combined with soy protein but not when combined with cod protein and casein. The lower serum triglyceride concentrations observed in the SPMO-fed rats could be the result of decreased hepatic triglycerides when soy protein was compared with casein and when menhaden oil was compared with coconut oil. Total LPL activity in the heart was higher in menhaden oil-fed rats than in coconut oil-fed rats in the postprandial state. The higher LPL activity in the heart could, however, explain only 10% of the reduction of serum triglycerides, contributing slightly to the lowering effects of SPMO diet on serum triglycerides. Therefore, the present results indicate that dietary proteins can modulate the effects of fish oil on triglyceridemia in the rat, and that could be mainly related to specific alterations in hepatic lipid concentrations.     

Screening and Profiling of Hydrocarbon Components and Squalene in Developing Tunisian Cultivars and Wild Arachis hypogaea L. Species

Total hydrocarbon composition and content of whole peanuts from three Tunisian varieties of peanut (two cultivars: AraC (Virginia type), AraT (Valencia type) and a wild one: AraA) were investigated during maturation. The results show that 30 hydrocarbons were identified from the wild AraA species, while only 27 hydrocarbon were detected in the cultivar ones. The hydrocarbon fraction is essentially composed of squalene, n-alkenes especially nC₁₄₌, nC₁₆₌, nC₁₈₌, nC₂₀₌ and nC₂₂₌, n-alkanes such as nC₁₆, nC₁₇, nC₁₈, nC₂₅, nC₂₆ and nC₂₇, and branched saturated hydrocarbon noted (HC₁, HC₂ and HC₃). Among the hydrocarbon components, generally the wild variety AraA presents the highest content of phytochemical squalene during maturation, whereas a maximum was detected from cultivar AraT at 12 days after podding (815.45 mg/100 g of oil). At maturity, the maximum level is reached at about 346.74 mg/100 g of oil for AraA. During maturity, wild AraA is considered to be an excellent source of squalene like olive and pumpkin oil.     

Treatment of odorous sulphur compounds by chemical scrubbing with hydrogen peroxide--stabilisation of the scrubbing solution

To slow down the hydrogen peroxide decomposition in basic aqueous conditions, the addition of stabilizers and co-stabilizers in the scrubbing solution was investigated. Results found with sodium silicate (Na2SiO3) were quite promising but several problems still remained. Based on these observations, this study focused on the research of a better stabilizer. Several ways were investigated: the use of silicate solutions employed in pulp industries, the addition of co-stabilizers to sodium silicate, or the use of an another stabilizer (the poly-alpha-hydroxyacrylic acid). Experiments revealed that the poly-alpha-hydroxyacrylic acid is the best stabilizing compound.     

Phase separation in the polyurethane/poly(2‐hydroxyethyl methacrylate) semi‐interpenetrating polymer networks synthesized by different ways

The thermal, dynamic mechanical analysis, morphology and mechanical properties of semi‐interpenetrating polymer networks based on crosslinked polyurethane (PU) and poly(2‐hydroxyethyl methacrylate) (PHEMA) synthesized by photopolymerization and by thermopolymerization have been investigated. The thermal analysis has evidenced the two glass temperature transitions in the semi‐IPNs and this is confirmed by the thermodynamic miscibility investigation of the systems. The Dynamic Mechanical Analysis spectra have shown that the phase separation is more significant in the thermopolymerized semi‐IPNs: the tan δ peaks of constituent polymers are more distinct and the minimum between the two peaks is deeper. The calculated segregation degree values of semi‐IPN's components are significantly higher for thermopolymerized semi‐IPNs, thereby the process of phase separation in the thermopolymerized semi‐IPNs is more developed. The structures of two series of samples investigated by SEM are completely different. The mechanical properties reflect these changes in structure of semi‐IPNs with increasing amount of PHEMA and with the changing of the method of synthesis. The results suggest that the studied semi‐IPNs are two‐phase systems with incomplete phase separation. The semi‐IPN samples with early stage of phase separation demonstrate higher mechanical characteristics. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

The lactoperoxidase system increases efficacy of high-pressure inactivation of foodborne bacteria

The inactivation of eight different bacteria comprising Escherichia coli LMM1010 and MG1655, respectively a pressure-resistant strain and the corresponding wild-type, Salmonella Typhimurium, Pseudomonas fluorescens, Staphylococcus aureus, Enterococcus faecalis, Listeria innocua and Lactobacillus plantarum, by high hydrostatic pressure in skim milk supplemented with the lactoperoxidase-hydrogen peroxide-thiocyanate (LP) system at naturally occurring concentration was studied. In the absence of pressure treatment, the LP system had either no effect, i.e. on S. Typhimurium and E. coli LMM1010, a growth inhibiting effect, i.e. on E. coli MG1655, L. innocua, S. aureus, L. plantarum and E. faecalis, or a bactericidal effect, i.e. on P. fluorescens. The presence of the LP system affected inactivation by high pressure in a cell density-dependent manner. At low cell concentration (10(6) cfu/ml), the LP system strongly increased high-pressure inactivation as measured immediately after pressure treatment of all bacteria except the pressure-resistant E. coli. At high cell density (10(9) cfu/ml), only inactivation of L. innocua, E. faecalis and L. plantarum were enhanced. For both E. coli strains, the fate of the bacteria during 24 h following pressure treatment was also studied. It was found that in the presence of the LP system, considerable further inactivation occurred in the first hours after pressure treatment. The potential of the LP system to improve the bactericidal efficiency of high-pressure treatment for food preservation is discussed.     

Interface Molecular Engineering for Laminated Monolithic Perovskite/Silicon Tandem Solar Cells with 80.4% Fill Factor

A multipurpose interconnection layer based on poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS), and d ‐sorbitol for monolithic perovskite/silicon tandem solar cells is introduced. The interconnection of independently processed silicon and perovskite subcells is a simple add‐on lamination step, alleviating common fabrication complexities of tandem devices. It is demonstrated experimentally and theoretically that PEDOT:PSS is an ideal building block for manipulating the mechanical and electrical functionality of the charge recombination layer by controlling the microstructure on the nano‐ and mesoscale. It is elucidated that the optimal functionality of the recombination layer relies on a gradient in the d ‐sorbitol dopant distribution that modulates the orientation of PEDOT across the PEDOT:PSS film. Using this modified PEDOT:PSS composite, a monolithic two‐terminal perovskite/silicon tandem solar cell with a steady‐state efficiency of 21.0%, a fill factor of 80.4%, and negligible open circuit voltage losses compared to single‐junction devices is shown. The versatility of this approach is further validated by presenting a laminated two‐terminal monolithic perovskite/organic tandem solar cell with 11.7% power conversion efficiency. It is envisioned that this lamination concept can be applied for the pairing of multiple photovoltaic and other thin film technologies, creating a universal platform that facilitates mass production of tandem devices with high efficiency.     

Sizing and optimization of high throughput radio‐frequency data down link of earth observation satellites

This paper analyses the sizing of networks of radio‐frequency ground stations operating at Ka band or above for the reception of data acquired by low earth orbit observation satellites. In particular, the way to account for the use of adaptive transmission schemes, to cope with the high propagation impairments in the troposphere is detailed. A solution to size optimally the ground stations and satellite memory, relying on propagation channel simulations, is also proposed. The resulting performances are assessed in a latter stage using simulated propagation time series. Copyright © 2015 John Wiley & Sons, Ltd.     

Corpus d'extraits musicaux: indices relatifs à la familiarité, à l'age d'acquisition et aux évocations verbales.

Studied the degree of familiarity, the age of acquisition, and verbal associations with regard to 144 musical excerpts drawn from the repertory of tunes that is expected to be shared by all French-speaking Quebec university students. Human Ss: 60 normal male and female Canadian adults (aged 21–45 yrs) (university students) (Group 1). 60 normal male and female Canadian adults (aged 19–43 yrs) (university students) (Group 2). The excerpts were presented to all Ss in synthesized, monophonic recordings. Ss in Group 1 were asked to indicate their degree of familiarity with each excerpt and the age at which they learned the excerpt. Ss in Group 2 were asked to indicate whether the original tune was vocal or instrumental and to provide verbal associations for the excerpts. The degree of familiarity, developmental period of acquisition, frequency of verbal associations, and dominant verbal association were determined for each excerpt. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)