El gallo de Léon

Electron energy-loss spectroscopy (EELS) in combination with scanning transmission electron microscopy ( STEM) reveals that the La enrichment at the surface of cerium-lanthanum solid solutions is an averaged effect and that segregation occurs in a mixed oxide phase. This separation occurs within a crystalline particle, where the dopant-rich phase is located at the surface of the dopant-deficient phase. The limiting structure appears to be a solid solution with a La fraction of x = 0.6 in the bulk and x = 0.75 at the surface. Up to a La fraction of 0.6, this phase will coexist with a lanthanum-type structure in different proportions depending on the dopant amount. STEM-EELS appears to be a powerful technique to clarify the existence of a multiphase system, and it shows that XRF, XPS, and XRD measure averaged results and do not show the phase complexity of the solids

Sometimes Sperm Whales (Physeter macrocephalus) Cannot Find Their Way Back to the High Seas: A Multidisciplinary Study on a Mass Stranding

BACKGROUND: Mass strandings of sperm whales (Physeter macrocephalus) remain peculiar and rather unexplained events, which rarely occur in the Mediterranean Sea. Solar cycles and related changes in the geomagnetic field, variations in water temperature and weather conditions, coast geographical features and human activities have been proposed as possible causes. In December 2009, a pod of seven male sperm whales stranded along the Adriatic coast of Southern Italy. This is the sixth instance from 1555 in this basin. METHODOLOGY/PRINCIPAL FINDINGS: Complete necropsies were performed on three whales whose bodies were in good condition, carrying out on sampled tissues histopathology, virology, bacteriology, parasitology, and screening of veins looking for gas emboli. Furthermore, samples for age determination, genetic studies, gastric content evaluation, stable isotopes and toxicology were taken from all the seven specimens. The animals were part of the same group and determined by genetic and photo-identification to be part of the Mediterranean population. Causes of death did not include biological agents, or the "gas and fat embolic syndrome", associated with direct sonar exposure. Environmental pollutant tissue concentrations were relatively high, in particular organochlorinated xenobiotics. Gastric content and morphologic tissue examinations showed a prolonged starvation, which likely caused, at its turn, the mobilization of lipophilic contaminants from the adipose tissue. Chemical compounds subsequently entered the blood circulation and may have impaired immune and nervous functions. CONCLUSIONS/SIGNIFICANCE: A multi-factorial cause underlying this sperm whales' mass stranding is proposed herein based upon the results of postmortem investigations as well as of the detailed analyses of the geographical and historical background. The seven sperm whales took the same "wrong way" into the Adriatic Sea, a potentially dangerous trap for Mediterranean sperm whales. Seismic surveys should be also regarded as potential co-factors, even if no evidence of direct impact has been detected

Valorisation du glycérol en acroléine

nationa

Effective heat transfers in packed bed: Experimental and model investigation

International audienc

Thermodynamic and experimental studies of catalytic reforming of exhaust gas recirculation in gasoline engines

International audienc

Oxidative dehydrogenation of ethyl lactate to ethyl pyruvate over vanadium and iron antimonates catalysts

International audienceThe oxidative dehydrogenation of ethyl lactate to ethyl pyruvate, corresponding to the first step of a new process in the industrial production of methionine, has been investigated. Iron and vanadium antimonates were developed as catalysts, and were optimized to reach 87% conversion of ethyl lactate, with 88% selectivity to ethyl pyruvate, at only 275 °C. The catalysts were characterized before and after catalytic testing, and in situ using various techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and XANES spectroscopy. The results show that neither the Sb 3+ /Sb 5+ nor the Fe 2+ /Fe 3+ redox couple were involved in the dehydrogenation of ethyl lactate, or in the catalysts re-oxidation. The active and selective catalytic sites correspond to surface V 5+ species. These species should not be considered as part of the bulk oxide, but as supra-surface species whose surface content is monitored with the bulk composition

Diagnosis of Cetacean morbillivirus A sensitive one step real time RT fast-PCR method based on SYBR® Green

Cetacean morbillivirus (CeMV) (family Paramyxoviridae, genus Morbillivirus) is considered the most pathogenic virus of cetaceans. It was first implicated in the bottlenose dolphin (Tursiops truncatus) mass stranding episode along the Northwestern Atlantic coast in the late 1980s, and in several more recent worldwide epizootics in different Odontoceti species. This study describes a new one step real-time reverse transcription fast polymerase chain reaction (real-time RT-fast PCR) method based on SYBR® Green to detect a fragment of the CeMV fusion protein gene. This primer set also works for conventional RT-PCR diagnosis. This method detected and identified all three well-characterized strains of CeMV porpoise morbillivirus (PMV), dolphin morbillivirus (DMV) and pilot whale morbillivirus (PWMV). Relative sensitivity was measured by comparing the results obtained from 10-fold dilution series of PMV and DMV positive controls and a PWMV field sample, to those obtained by the previously described conventional phosphoprotein gene based RT-PCR method. Both the conventional and real-time RT-PCR methods involving the fusion protein gene were 100- to 1000-fold more sensitive than the previously described conventional RT-PCR method. © 2015 Elsevier B.V

Oxygen non-stoichiometry phenomena in Pr1-xZrxO2-y compounds (0.02 < x < 0.5).

New Pr1-xZrxO2-y oxides with x < 0.5 have been prepared by co-precipitation in basic medium and annealed under air at high temperatures (T≤ 1200 °C). Defined compositions with x = 0.02, 0.1, 0.2, 0.35, 0.40 and 0.5 have been characterized by XRD, Zr-K-edge EXAFS for the local structure, magnetic susceptibility measurements, and Pr LIII-edge XANES in order to identify the variation of the cell parameter and Zr local environment versus Zr content and Pr(n+) (4 < n < 3) oxidation states. The higher the Zr content, the lower the Pr valence state. The Zr amount stabilized in the distorted octahedral site is at the origin of the formation of defined compositions as discovered by Leroy Eyring et al. in the PrnO2n-2m series and the generation of oxygen vacancies stabilized in the fluorite-type network. TGA and TPR analyses help to follow the reduction properties under Ar/5% H2 and show high Pr reducible rates at low temperatures (T < 250 °C). The identification of the fluorite-type superstructure (SG: Ia3[combining macron]) of reduced compositions annealed at T = 900 °C under Ar/5% H2 shows the cationic and oxygen vacancy ordering. This feature plays a key role with Zr(4+) cations stabilized in flattened octahedral sites for the generation of oxygen vacancies and the stabilization of Pr(3+) in the reduced states