La fonte lipidique du foie gras à la cuisson

La connaissance des facteurs biologiques, zootechniques et technologiques ainsi que des mécanismes qui contrôlent le taux de fonte des foies gras à la cuisson est primordiale pour la maîtrise du rendement technologique des foies gras. En effet, le taux de fonte à la cuisson a des répercussions sur les qualités organoleptiques des foies gras et sur les performances des unités de production

Implementation of ‘chaotic’ advection for viscous fluids in heat exchanger/reactors

When viscous fluids are involved, laminar hydraulic conditions and heat and mass transfer intensification are conflicting phenomena. A channel geometry based on Split-And-Recombine (SAR) patterns is experimentally investigated. The principle implements the Baker’s transformation and ‘chaotic’ structures are generated to promote heat and mass transfer. This work assesses the energy efficiency of different heat exchanger/reactors integrating these SAR patterns. The heat transfer capacity is assessed and compared with the energy consumption of each mock-up. It is sensitive to the cooling mode and to the number of SAR patterns per length unit as well. The continuous oxidation of sodium thiosulfate with hydrogen peroxide has been implemented. Conversions up to 99% are reached according to the utility fluid temperature and the residence time. Finally, the whole performances of the SAR geometries are compared to a plate-type heat exchanger/reactor with a corrugated pattern. The more viscous the fluid, the more the energy efficiency of the SAR design increases compared to the corrugated design because of the balance between advection and diffusion mechanisms. The interest in terms of energy efficiency in working with SAR heat exchanger/reactor appears from Reynolds numbers below 50

pH-Responsive Bridged Silsesquioxane

International audienceABSTRACT: A pH-responsive bridged silsesquioxane was obtained via the sol gel process from a bis-silylated triazine derivative bearing a triple DAD (donor- acceptor- donor) moiety which was strongly hydrogen-bonded to the three ADA (acceptor- donor- acceptor) sites of cyanuric acid. The latter template molecule was easily removed from the resulting hybrid material upon acidic treatment, which yielded the template-free bridged silsesquioxane with preserved morphology and unaltered particle size as demonstrated by SEM. As expected, the surface area of the acid-treated hybrid was significantly higher than that of the untreated material, as demonstrated by nitrogen adsorption measurements. The absence of cyanuric acid in this material was confirmed by solid state NMR and by IR. It was shown that amild acidic medium (pH = 5.5) is sufficient to release the cyanuric acid template, thus providing a novel route to new hybrid materials with potential applications as efficient carriers for pH-responsive delivery systems

Effects of oil exposure and dispersant use upon environmental adaptation performance and fitness in the European sea bass, Dicentrarchus labrax.

International audienceThe worldwide increasing recourse to chemical dispersants to deal with oil spills in marine coastal ecosystems is a controversial issue. Yet, there exists no adequate methodology that can provide reliable predictions of how oil and dispersant-treated oil can affect relevant organism or population-level performance. The primary objective of the present study was to examine and compare the effects of exposure to untreated oil (weathered Arabian light crude oil), chemically dispersed oil (Finasol, TOTAL-Fluides) or dispersant alone, upon the ability of fish for environmental adaptation. To reach that goal, we implemented high-throughput, non-lethal challenge tests to estimate individual hypoxia and heat tolerance as surrogate measures of their capacity to face natural contingencies. Experimental populations were then transferred into semi-natural tidal ponds and correlates of individuals' fitness (growth and survival) were monitored over a period of 6 months. In accordance with our stated objectives, the contamination conditions tested corresponded to those observed under an oil slick drifting in shallow waters. Our results revealed that the response of control fish to both challenges was variable among individuals and temporally stable (repeatable) over a 2-month period. Exposure to chemical dispersant did not affect the repeatability of fish performance. However, exposure to oil or to a mixture of oil plus dispersant affected the repeatability of individuals' responses to the experimental challenge tests. At population level, no difference between contamination treatments was observed in the distribution of individual responses to the hypoxia and temperature challenge tests. Moreover, no correlation between hypoxia tolerance and heat tolerance was noticed. During the field experiment, hypoxia tolerance and heat tolerance were found to be determinants of survivorship. Moreover, experimental groups exposed to oil or to dispersant-treated oil displayed significantly lower survival than control or dispersant-exposed groups. Finally, from the four experimental populations tested, the one exposed to chemically dispersed oil presented the lowest growth rate

Putative Protein Biomarkers of Escherichia coli Antibiotic Multiresistance Identified by MALDI Mass Spectrometry

International audienceThe commensal bacteria Escherichia coli causes several intestinal and extra-intestinal diseases, since it has virulence factors that interfere in important cellular processes. These bacteria also have a great capacity to spread the resistance genes, sometimes to phylogenetically distant bacteria, which poses an additional threat to public health worldwide. Here, we aimed to use the analytical potential of MALDI-TOF mass spectrometry (MS) to characterize E. coli isolates and identify proteins associated closely with antibiotic resistance. Thirty strains of extended-spectrum beta-lactamase producing E. coli were sampled from various animals. The phenotypes of antibiotic resistance were determined according to Clinical and Laboratory Standards Institute (CLSI) methods, and they showed that all bacterial isolates were multi-resistant to trimethoprim-sulfamethoxazole, tetracycline, and ampicillin. To identify peptides characteristic of resistance to particular antibiotics, each strain was grown in the presence or absence of the different antibiotics, and then proteins were extracted from the cells. The protein fingerprints of the samples were determined by MALDI-TOF MS in linear mode over a mass range of 2 to 20 kDa. The spectra obtained were compared by using the ClinProTools bioinformatics software, using three machine learning classification algorithms. A putative species biomarker was also detected at a peak m/z of 4528.00

Venous gas emboli are involved in post-dive macro, but not microvascular dysfunction

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A Designed 5-Fluorouracil-Based Bridged Silsesquioxane as an AutonomousnAcid-Triggered Drug-Delivery System

9 pagesInternational audienceTwo new prodrugs, bearing two and three 5-fluorouracil (5-FU) units, respectively, have been synthesized and were shown to efficiently treat human breast cancer cells. In addition to 5-FU, they were intended to form complexes through H-bonds to an organo-bridged silane prior to hydrolysis-condensation through sol-gel processes to construct acid-responsive bridged silsesquioxanes (BS). Whereas 5-FU itself and the prodrug bearing two 5-FU units completely leached out from the corresponding materials, the prodrug bearing three 5-FU units was successfully maintained in the resulting BS. Solid-state NMR (29Si and 13C) spectroscopy show that the organic fragments of the organo-bridged silane are retained in the hybrid through covalent bonding and the 1H NMR spectroscopic analysis provides evidence for the hydrogen-bonding interactions between the prodrug bearing three 5-FU units and the triazine-based hybrid matrix. The complex in the BS is not affected under neutral medium and operatesnunder acidic conditions even under pH as high as 5 to deliver the drug as demonstrated by HPLC analysis and confirmed by FTIR and 13C NMR spectroscopic studies. Such functional BS are promising materials as carriers to avoid the side effects of the anticancer drug 5-FU thanks to a controlled and targeted drug delivery