Simulation of synthetic climate at local scale as a mean to assess the impact of climate change on infrastructures

A global modelling approach for estimating the climate influence on corrosion activity in reinforced concrete is developed. It combines: (a) the identification of statistical properties of climates in various temperate regions, and the development of a synthetic simulator able to reproduce its dominant patterns, (b) the identification of an empirical corrosion activity model, based on the analysis of experimental data, highlighting the respective influence of temperature and humidity. Synthetic simulations combining these two models are carried out. They show the complexity of the interactions, since the influence of temperature and humidity may be adverse, and the interest to describe both random fluctuations at daily scale and at seasonal scale. They confirm that monitoring of corrosion must account for this time variability and propose a way to estimate average corrosion even with measurements which would remain limited to a short period. Synthetic simulations are also used for estimating the influence of a global warming scenario on the corrosion activity. A global increase of about 38% of corrosion activity has been estimated in response to an average temperature elevation of 3°C.     

Use of semantic context by patients with Alzheimer's disease.

Used semantic-priming procedures to examine limitations in the use of semantic context by 18 patients (mean age 68.9 yrs) with Alzheimer's disease (AD) and to determine whether any such contextual effects were mediated solely through automatic processes or whether attentional processes were also involved. Three tasks were applied to examine the effect of semantic context on the performance of 18 normal elderly Ss (mean age 67.2 yrs), 18 normal young Ss (mean age 24.1 yrs), and the AD Ss. When normal and AD Ss were asked to decide whether a given item was a member of a certain category, their response times were equally affected by the item's dominance in the category. The time that AD Ss took to recognize a word was actually affected more by the semantic context provided by a priming sentence than was that of normal Ss. When asked to generate the final word of an incomplete sentence, AD Ss performed very poorly unless potential responses were highly constrained by sentence context. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

African sleeping sickness in Switzerland (trypanosomiasis rhodesiensis)

The fatal course of a case of African trypanosomiasis in Switzerland is reported. The feeling of sickness after an African trip is a diagnostic pointer. An infected fly bite and enlargement of lymphatic nodes or even symptoms of involvement of the central nervous system increase the suspicion. The diagnosis may be established simply by microscopic examination of a blood film. Because of the possibility of severe complications due to the sickness itself or due to toxicity of specific drugs, patients should be treated in hospital. Immediate contact with an Institute for tropical diseases seems to be advisable in every case.     

ST6GALNAC5 Expression Decreases the Interactions between Breast Cancer Cells and the Human Blood-Brain Barrier

The ST6GALNAC5 gene that encodes an α2,6-sialyltransferase involved in the biosynthesis of α-series gangliosides, was previously identified as one of the genes that mediate breast cancer metastasis to the brain. We have shown that the expression of ST6GALNAC5 in MDA-MB-231 breast cancer cells resulted in the expression of G_D1α ganglioside at the cell surface. By using a human blood-brain barrier in vitro model recently developed, consisting in CD34⁺ derived endothelial cells co-cultivated with pericytes, we show that ST6GALNAC5 expression decreased the interactions between the breast cancer cells and the human blood-brain barrier.     

Structural/textural properties and water reactivity of fluorinated activated carbons

Hydrophobic activated carbons are considered as interesting materials for air or water remediation due to their enhanced affinity for slightly water-soluble organic species. In this context, a commercial activated carbon, in an extruded form, was fluorinated under mild conditions (pure fluorine gas at room temperature) in order to decrease its hydrophilic character and to preserve its microporosity. For comparison, a hydrogenated activated carbon was also prepared by H₂ treatment. The resulting samples were characterised by various techniques in order to determine the evolution of the activated carbon materials in terms of composition (XPS, elemental analysis, TGA and NMR) and porosity (nitrogen physisorption (77 K), mercury intrusion and immersion calorimetry). For the fluorinated carbon, the nature of the CF_x groups and the strength of the C–F bonds were also investigated using ¹³C and ¹⁹F solid state NMR and TGA techniques. A labile character of the C–F bond, so far exclusively observed for fluorine intercalation compounds, is also shown for the first time for a fluorinated activated carbon by water adsorption/desorption isotherms at room temperature. Care should then be taken for its use in presence of water.     

Incongruence between the cps type 2 genotype and host-related phenotypes of an Enterococcus faecalis food isolate

Enterococcus faecalis is a nosocomial opportunistic pathogen, but is also found in fermented food products where it plays a fundamental role in the fermentation process. Previously, we have described the non-starter E. faecalis cheese isolate QA29b as harboring virulence genes and proven to be virulent in Galleria mellonella virulence model. In this study, we further characterized this food strain concerning traits relevant for the host-pathogen relationship. QA29b was found to belong to sequence type (ST) 72, a common ST among food isolates, and thus we consider it as a good representative of food E. faecalis strains. It demonstrated high ability to form biofilms, to adhere to epithelial cells and was readily eliminated by J774.A1 macrophage cells. Despite carrying the cps locus associated with the capsular polysaccharide CPS 2 type, cps genes were not expressed, likely due to an IS6770 inserted in the cpsC-cpsK promoter region. This work constitutes the first study of traits important for interaction, colonization and infection in the host performed on a good representative of E. faecalis food isolates. Reported results stress the need for a reliable serotyping assay of E. faecalis, as cps genotyping may not be reliable. Overall, QA29b characterization shows that despite its virulence potential in an insect model, this food strain is readily eliminated by mammalian macrophages. Thus, fine tuned approaches combining cellular and mammalian models are needed to address and elucidate the multifactorial aspect of virulence potential associated with food isolates.     

Thermal oxidation studies on reduced folate, L-5-methyltetrahydrofolic acid (L-5-MTHF) and strategies for stabilization using food matrices

The thermal stability of L-5-methyltetrafolic acid (L-5-MTHF) was investigated in model/buffer systems and food systems. L-5-MTHF degradation followed first-order reaction kinetics with relatively greater (P < 0.01) stability at pH 4 compared to pH 6.8 in the buffer systems. This was confirmed using cyclic voltammetry. The stability (for example, k-values) of L-5-MTHF in an oxygen controlled environment improved (P < 0.001) proportionally when in the presence of increasing molar ratios of sodium ascorbate (NaAsc). The addition of NaAsc to L-5-MTHF after heat treatment was also effective at returning thermally oxidized L-5-MTHF back to its original form. A scheme was developed to explain the degradation and regeneration of L-5-MTHF. The importance of antioxidant protection of L-5-MTHF from thermal oxidation was extended using 2 distinct food systems; namely skim milk and soy milk, both with known antioxidant capacities. We conclude that the antioxidant activity of food components can enhance the stability of L-5-MTHF.     

Synthesis,characterization and solubility of mixed zirconium-cerium molybdate precipitates

The reaction between fission products Mo(VI) and Zr(IV) in hot nitric acid solution during the spent fuel dissolution process leads to the formation of hydrated zirconium molybdate precipitate. This solid can include other metallic cations at the 4th oxidation state (+ IV) inside the crystal such as Pu(IV).

Precipitations in the inactive surrogate system of mixed zirconium-cerium molybdates Mo-Zr(IV)-Ce(IV) were performed all over the cerium molar percentage scale from 0 to 100%, Ce(IV) being used as a surrogate of Pu(IV). The crystal structures were identified from powder X-ray diffraction patterns and complementary investigations by SEM and elemental analyses were carried out. The solid composition pointed out two phases that are ZrMo₂O₇(OH)₂(H₂O)₂ and Ce₃Mo₆O₂₄(H₂O)₄. Each of these compounds was proved being a solid solution within which the Zr^IV and Ce^IV atoms can substitute each other.

Moreover, the influence of the cerium molar fraction on the precipitate solubility was investigated and showed a strong evolution of solubility not only with the nature of the precipitate and the Ce content, but also with the nitric acid concentration.     

40 years of Dogger aquifer management in Ile-de-France, Paris Basin, France

Geothermal energy has been supplying heat to district networks in the Paris Basin for more than 40 years. The most serious difficulties have been corrosion and scaling related problems that occurred in many geothermal loops in the mid-1980s. The main target of all exploration and exploitation projects has been the Dogger aquifer. Most of the operating facilities use the “doublet” technology which consists of a closed loop with one production well and one injection well. Injection of the cooled brines leads to the progressive exhaustion of the resource at the local doublet scale. Consequently, most of the research effort has been focused on quantifying the temporal evolution of the cooling, and to forecast the lifetimes of doublets and the occurrence of the “thermal breakthrough”. At the turn of the 21st century, there was a revival of geothermal energy development in France and new projects are presently being considered. The 40 years of experience in geothermal exploitation of the Paris basin constitutes a firm basis upon which to devise a sustainable regional management approach for the geothermal resource. Several governmental policies seek to promote further geothermal development of the Dogger aquifer with structures in place to facilitate technical studies.