Contamination of packaged food by substances migrating from a direct-contact plastic layer: Assessment using a generic quantitative household scale methodology

The contamination risk in 12 packaged foods by substances released from the plastic contact layer has been evaluated using a novel modeling technique, which predicts the migration that accounts for (i) possible variations in the time of contact between foodstuffs and packaging and (ii) uncertainty in physico-chemical parameters used to predict migration. Contamination data, which are subject to variability and uncertainty, are derived through a stochastic resolution of transport equations, which control the migration into food. Distributions of contact times between packaging materials and foodstuffs were reconstructed from the volumes and frequencies of purchases of a given panel of 6422 households, making assumptions about household storage behaviour. The risk of contamination of the packaged foods was estimated for styrene (a monomer found in polystyrene yogurt pots) and 2,6-di-tert-butyl-4-hydroxytoluene (a representative of the widely used phenolic antioxidants). The results are analysed and discussed regarding sensitivity of the model to the set parameters and chosen assumptions.     

Over-expression of the Anti-apoptotic Protein Bcl-2 Affects Membrane Lipid Composition in HL-60 Cells

We studied modifications induced at the membrane lipid level by over-expression of the anti-apoptotic protein Bcl-2. When total cell phospholipids were analyzed, the transformation led to a moderate decrease in poly-unsaturated fatty acids, compensated by an increase in mono-unsaturated species. At the mitochondrial membrane level, the changes were more important and occurred in saturated and dimethyl acetal fatty acids, which became more abundant, while unsaturated fatty acid content diminished. This indicates a decline in oxidation-sensitive fatty acids (unsaturated species) together with a gain in oxidation-insensitive saturated fatty acids and in plasmalogen (as detected by dimethyl acetal fatty acids) considered as oxygen species scavengers. Theses changes, combined with the protective role of Bcl-2 against oxidation due to its effect on the redox potential, should protect cells from apoptosis starting in mitochondria. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Ultrastructural Interactions and Genotoxicity Assay of Cerium Dioxide Nanoparticles on Mouse Oocytes

Cerium dioxide nanoparticles (C_eO₂ ENPs) are on the priority list of nanomaterials requiring evaluation. We performed in vitro assays on mature mouse oocytes incubated with C_eO₂ ENPs to study (1) physicochemical biotransformation of ENPs in culture medium; (2) ultrastructural interactions with follicular cells and oocytes using Transmission Electron Microscopy (TEM); (3) genotoxicity of C_eO₂ ENPs on follicular cells and oocytes using a comet assay. DNA damage was quantified as Olive Tail Moment. We show that ENPs aggregated, but their crystal structure remained stable in culture medium. TEM showed endocytosis of C_eO₂ ENP aggregates in follicular cells. In oocytes, C_eO₂ ENP aggregates were only observed around the zona pellucida (ZP). The comet assay revealed significant DNA damage in follicular cells. In oocytes, the comet assay showed a dose-related increase in DNA damage and a significant increase only at the highest concentrations. DNA damage decreased significantly both in follicular cells and in oocytes when an anti-oxidant agent was added in the culture medium. We hypothesise that at low concentrations of C_eO₂ ENPs oocytes could be protected against indirect oxidative stress due to a double defence system composed of follicular cells and ZP.     

Nanostructured current-confined single quantum dot light-emitting diode at 1300 nm

A novel light-emitting-diode structure is demonstrated, which relies on nanoscale current injection through an oxide aperture to achieve selective excitation of single InAs/GaAs quantum dots. Low-temperature electroluminescence spectra evidence discrete narrow lines around 1300 nm (line width approximately 75 microeV) at ultralow currents, which are assigned to the emission from single excitons and multiexcitons. This approach, which enables the fabrication of efficient nanoscale active devices at 1300 nm, can provide single-photon-emitting diodes for fiber-based quantum cryptography.     

The impact of driver age on lost life years for other road users in France: A population based study of crash-involved road users

BACKGROUND: One of the concerns in road safety is the threat older drivers may pose to other road users. Using the rate of lost life years, the present study provides a public health approach to quantify this potential threat. METHODS: A total of 1570686 motorised vehicle drivers or motorcycle riders and 652246 non-drivers, i.e. vehicle passengers, pedestrians and cyclists involved in injury crashes in France between 1996 and 2004, were included in a population based cross-sectional study. Fatality rates and rate of lost life years for each crash-involved driver age class were calculated for the drivers themselves and for other road users. RESULTS: The study has shown a significant reduction in the rate of lost life years for crash-involved other road users (whether passengers, pedestrians, cyclists or opposing drivers) as driver age increases. Other road users lost half as many years of life when involved in crashes with drivers aged over 85 than with drivers under 65 (1.26 and 2.32 per 100 expected remaining life years, respectively). CONCLUSION: Our findings suggest that among road users involved in injury crashes, older drivers are less dangerous for the other road users. By attributing other road users' lost life years to each driver age, this study represents a new contribution to the debate about ageing and road safety.     

The Xanthophyll Carotenoid Lutein Reduces the Invasive Potential of Pseudomonas aeruginosa and Increases Its Susceptibility to Tobramycin

Recently, the xanthophyll carotenoid lutein has been qualified as a potential quorum sensing (QS) and biofilm inhibitor against Pseudomonas aeruginosa. To address the potential of this xanthophyll compound as a relevant antivirulence agent, we investigated in depth its impact on the invasion capabilities and aggressiveness of P. aeruginosa PAO1, which rely on the bacterial ability to build and maintain protective barriers, use different types of motilities and release myriad virulence factors, leading to host cell and tissue damages. Our data, obtained on the PAO1 strain, indicate that all-trans lutein (Lut; 22 µM) disrupts biofilm formation and disorganizes established biofilm structure without affecting bacterial viability, while improving the bactericidal activity of tobramycin against biofilm-encapsulated PAO1 cells. Furthermore, this xanthophyll affects PAO1 twitching and swarming motilities while reducing the production of the extracellular virulence factors pyocyanin, elastase and rhamnolipids as well as the expression of the QS-regulated lasB and rhlA genes without inhibiting the QS-independent aceA gene. Interestingly, the expression of the QS regulators rhlR/I and lasR/I is significantly reduced as well as that of the global virulence factor regulator vfr, which is suggested to be a major target of Lut. Finally, an oxidative metabolite of Lut, 3′-dehydrolutein, induces a similar inhibition phenotype. Taken together, lutein-type compounds represent potential agents to control the invasive ability and antibiotic resistance of P. aeruginosa.     

Micromorphological description of vernacular cob process and comparison with rammed earth

Past builders have developed very low-embodied energy construction techniques optimizing the use of local building materials. These techniques are a source of inspiration for modern sustainable building. Unfortunately, this know-how was orally transmitted and was lost as earth construction fell into disuse during the 20th century in European countries. The absence of written documents makes necessary to use an archaeological approach in order to rediscover these construction strategies. Micromorphological analysis of thin sections collected in earth building walls was used for the first time to describe cob construction technique and highlighted several typical pedofeatures allowing to clearly identifying this process. Finally, a first comparison of the cob and rammed earth micromorphological features permitted to identify two key factors to distinguish these two techniques, the manufacturing state (solid or plastic) and the organization of the material in the wall.     

Water chemical potential: A key parameter to determine the thermodynamic stability of some hydrated cement phases in concrete?

The CaO-Al₂O₃-SO₃-H₂O system at 25 °C under 1 bar of pressure has been investigated with phase diagrams software (Zen + k) based on chemical potentials (or activities). The reported invariant points are similar to those obtained previously using equilibrium calculations. However Zen + k enables us to calculate systems at different relative humidities, and in conditions where water is not in excess, calcium monosulfoaluminate could be a stable phase and thus, as observed experimentally, remain for long times in an ordinary Portland cement paste.     

The role of expertise in tool use: Skill differences in functional action adaptations to task constraints.

Tool use can be considered a particularly useful model to understand the nature of functional actions. In 3 experiments, tool-use actions typified by stone knapping were investigated. Participants had to detach stone flakes from a flint core through a conchoidal fracture. Successful flake detachment requires controlling various functional parameters simultaneously. Accordingly, our goals were twofold: (a) to examine the regulation of kinetic energy by varying the properties of the hammers and the goal, and (b) to characterize the difference in action regulation across skill levels. All groups were able to modify their actions according to changes in task goals, but only experts displayed fine-tuning to functional parameters (i.e., regulate actions according to changes in hammer weight in a manner that left kinetic energy unchanged). Expertise is considered to depend on the identification of the interactions between functional parameters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)