562 research outputs found

    Evaluation of a TiO2 photocatalysis treatment on nitrophenols and nitramines contaminated plant wastewaters by solid-phase extraction coupled with ESI HPLC–MS

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    Nitration reactions of aromatic compounds are commonly involved in different industrial processes for pharmaceutical, pesticide or military uses. For many years, most of the manufacturing sites used lagooning systems to treat their process effluents. In view of a photocatalytic degradation assay, the wastewater of a lagoon was investigated by using HPLC coupled with mass spectrometry. The wastewater was highly concentrated in RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), HMX (octahydro- 1,3,5,7-tetranitro-1,3,5,7-tetrazocine) and two herbicides Dinoterb (2-tert-butyl-4,6-dinitrophenol) and Dinoseb (2-sec-butyl-4,6-dinitrophenol). First of all, an analytical method using solid-phase extraction (SPE) combined with HPLC ESI MS/MS was put in work for identification and titration of RDX, HMX and the two dinitrophenols in a complex natural matrix. Then, the UV/TiO2 treatment was investigated for pollutants removal. Dinitrophenolic compoundswere significantly degraded after a 8-h-exposition of the wastewater/TiO2 suspension, whereas RDX and HMX were poorly affected

    Microbial population changes during bioremediation of nitroaromatic - and nitramine-contaminated lagoon

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    Nitration reactions of aromatic compounds are commonly involved in military industrial processes. Military industries treated their process effluents using lagoon systems for many years. In this study, the sediment of a lagoon was investigated from a bioremediation objective. The physico-chemical characterization of the sediments showed the organic nature of the sediment (25.4% carbon with a C:N ¼ 3) highly concentrated in RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) as well as two herbicides Dinoterb (2-tert-butyl-4,6-dinitrophenol) and Dinoseb (2-sec-butyl-4,6-dinitrophenol). Analysis of the 16S rRNA gene clone library revealed the presence of three dominant families, Geobacteriacea, Clostridiaceae and Pseudomonaceae. A bioremediation assay was carried out in anaerobic conditions in order to degrade organic compounds. In these conditions, 100% of Dinoterb and Dinoseb were degraded after 75 days of culture, while RDX and HMX were not consumed. The 16S rRNA gene clone library analysis of this incubation showed a drastic reduction of the final biodiversity composed by clones related to Enterobacteriaceae (especially Leclercia adecarboxylata) and Pseudomonaceae family. It was then suggested that Enterobacteriaceae and Pseudomonaceae were potentially involved in biodegradation of these two herbicides. To confirm this hypothesis, cultures were carried out with isolated species of Pseudomonas putida, Pseudomonas citronellolis and L. adecarboxylata in the presence of Dinoterb. The data confirmed that in the presence of glucose, these microorganisms are able to consume Dinoterb

    Catalytic methylation of aromatic amines with formic acid as the unique carbon and hydrogen source

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    International audienceA novel methodology is presented for the direct methylation of amines, using formic acid as a unique source of carbon and hydrogen. Based on ruthenium(II) catalysts, the formation of the N-CH3 group proceeds via an efficient formylation/transfer hydrogenation pathwa

    Nitrite complexes of the rare earth elements

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    International audienceThe coordination chemistry of the nitrite anion has been investigated with rare earth elements, and the resulting complexes were structurally characterized. Among them, the first homoleptic examples of nitrite complexes of samarium, ytterbium and yttrium are described. The coordination behavior of the nitrite ion is directly controlled by the ionic radius of the metal cation. While the nitrito ligand is stable in the coordination sphere of cerium(III), it is readily reduced by SmI2

    Gene flow and genetic divergence among mainland and insular populations across the south-western range of the Eurasian treecreeper (Certhia familiaris , Aves)

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    International audienceThe Eurasian treecreeper (Certhia familiaris) comprises two mitochondrial lineages that diverged during the mid-Pleistocene. One palaeoendemic lineage has an allopatric range currently restricted to the island of Corsica and the Caucasus region, whereas the second one has a very large Eurasian range. Here, we used microsatellites (N = 6) and mitochondrial DNA (COI) to assess the genetic structure of insular and mainland populations from Corsica, mainland France and Central Italy (N = 258) and the level of mitochondrial and nuclear gene flow among these populations. Concordant with the mitochondrial DNA signal, the results for microsatellites clearly demonstrate that the Corsican population (Certhia familiaris corsa) is strongly divergent from nearby mainland populations (Certhia familiaris macrodactyla). Microsatellite data also support significant divergence and low gene flow between the Central Italian and mainland French populations. Our results suggest low nuclear gene flow from the mainland into Corsica and no mitochondrial gene flow. Sporadic gene flow from the nearby mainland might explain the presence of continental nuclear alleles in the genome of 5% of sampled insular birds. Our study confirms the existence of an endemic Corsican treecreeper lineage with important conservation value. Our results also imply that Eurasian treecreepers from Central Italy constitute a distinct management unit

    Quantitative comparison of fuel spray images obtained using ultrafast coherent and incoherent double-pulsed illumination

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    We present a quantitative comparison between the high-pressure fuel spray images obtained experimentally using classical imaging with coherent and incoherent ultrafast illuminations recorded using a compatible CMOS camera. The ultrafast, incoherent illumination source was extracted from the supercontinuum generated by tightly focusing the femtosecond laser pulses in water. The average velocity maps computed using time-correlated image-pairs and spray edge complexity computed using the average curvature scale space maps are compared for the spray images obtained with the two illumination techniques and also for the numerically simulated spray using the coupled volume of fluid and level set method for interface tracking (direct numerical simulation or DNS). The spray images obtained with supercontinuum-derived, incoherent, ultrafast illumination are clearer, since the artifacts arising due to laser speckles and multiple diffraction effects are largely reduced and show a better correlation with the DNS results.Comment: 8 pages, 9 figures, Presented at the ILASS-Europe 2014, 26th Annual Conference on Liquid Atomization and Spray Systems held at Bremen, Germany from 8th to 10th September 201

    Synthesis, Structure and Electrochemical Behavior of New RPONOP (R = tBu, iPr) Pincer Complexes of the Fe2+, Co2+, Ni2+ and Zn2+ ions.

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    International audienceThe coordination chemistry of the M2+ ions of the first row elements iron, cobalt, nickel and zinc was explored with the ligands RPONOP (2,6-(R2PO)(C5H3N), R = iPr and tBu). Syntheses and characterization of the complexes Fe(RPONOP)Br2, Co(tBuPONOP)Cl2, Ni(RPONOP)I2 and Zn(RPONOP)I2 (R = tBu, iPr) are reported together with the crystal structures of Fe(RPONOP)Br2 (R = iPr and tBu), Co(tBuPONOP)Cl2, Co(iPrPONOP)Cl(m-Cl)CoCl2(THF), Ni(iPrPONOP)I2, Zn(iPrPONOP)I2 and of the oxidation product Zn[tBuP(=O)ONOP(=O)]I2 resulting from reaction with oxygen. The electrochemical behavior of the M(tBuPONOP)X2 complexes has been investigated in acetonitrile. While the nickel compound is stable, all the complexes are sensitive to dissociation of the RPONOP ligand or ligand scrambling in strongly coordinating media. Catalytic activity in formic acid dehydrogenation with TONs up to 1143 has been found for Ni(tBuPONOP)I2

    Population Structure and Dispersal Patterns within and between Atlantic and Mediterranean Populations of a Large-Range Pelagic Seabird

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    Dispersal is critically linked to the demographic and evolutionary trajectories of populations, but in most seabird species it may be difficult to estimate. Using molecular tools, we explored population structure and the spatial dispersal pattern of a highly pelagic but philopatric seabird, the Cory's shearwater Calonectris diomedea. Microsatellite fragments were analysed from samples collected across almost the entire breeding range of the species. To help disentangle the taxonomic status of the two subspecies described, the Atlantic form C. d. borealis and the Mediterranean form C. d. diomedea, we analysed genetic divergence between subspecies and quantified both historical and recent migration rates between the Mediterranean and Atlantic basins. We also searched for evidence of isolation by distance (IBD) and addressed spatial patterns of gene flow. We found a low genetic structure in the Mediterranean basin. Conversely, strong genetic differentiation appeared in the Atlantic basin. Even if the species was mostly philopatric (97%), results suggest recent dispersal between basins, especially from the Atlantic to the Mediterranean (aprox. 10% of migrants/generation across the last two generations). Long-term gene flow analyses also suggested an historical exchange between basins (about 70 breeders/generation). Spatial analysis of genetic variation indicates that distance is not the main factor in shaping genetic structure in this species. Given our results we recommend gathering more data before concluded whether these taxa should be treated as two species or subspecies. © 2013 Genovart et al.Peer Reviewe

    Georges Hémery (1952–2013). Disparition d’un éminent biologiste des populations

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