WorldWideScience

Sample records for aux oxyanions selenite

  1. Study of the Cupriavidus metallidurans CH34 resistance of selenite and selenate oxy-anions: accumulation, localisation and transformation of selenium; Etude de la resistance de Cupriavidus metallidurans CH34 aux oxyanions selenite et seleniate: accumulation, localisation et transformation du selenium

    Energy Technology Data Exchange (ETDEWEB)

    Avoscan, L

    2007-06-15

    Selenium is an essential trace element for the living organisms but it is very toxic at high concentration. Selenite and selenate oxides, soluble forms, highly toxic and bio-assimilable, are the most prevalent forms in the environment. Some soil micro-organisms play a dominant role and contribute to the natural cycle of selenium. Our study model, Cupriavidus (formerly Ralstonia) metallidurans CH34, a telluric bacterium characteristic of metal-contaminated biotopes, is known to resist selenite by reducing it into elemental selenium, an insoluble and less toxic form of selenium. In order to better understand the mechanisms of selenium reduction in the bacteria, three methods of speciation were combined (XAS (XANES and EXAFS), HPLC-ICP-MS and SDS-PAGEPIXE). They were completed by the direct quantification of selenium accumulated in the bacteria. Speciation analyses highlighted the existence of two mechanisms of reduction of selenium oxides in C. metallidurans CH34. Assimilation transforms selenite and selenate into organic selenium, identified as seleno-methionine and leads to its non-specific incorporation into bacterial proteins (presence of selenious proteins). Detoxication precipitates selenite in nano-particles of elemental selenium. This way of detoxication is not set up after an exposure to selenate although it is nevertheless possible to detect elemental selenium but in very small amount compared to the exposure of selenite. Seleno-diglutathion is detected in bacteria stressed by an exposure to selenate in medium limited in sulphate. Bacteria exposed to selenite accumulate 25 times more selenium than when they are exposed to selenate. The study of mutants resistant to selenite, which do not express the membrane protein DedA, showed that the accumulation of selenium after exposure to selenite is decreased compared with the wild strain meaning probable link between the transport of selenite and the DedA protein. Finally, selenate would use the sulphate permease

  2. Study of the Cupriavidus metallidurans CH34 resistance of selenite and selenate oxy-anions: accumulation, localisation and transformation of selenium

    International Nuclear Information System (INIS)

    Avoscan, L.

    2007-06-01

    Selenium is an essential trace element for the living organisms but it is very toxic at high concentration. Selenite and selenate oxides, soluble forms, highly toxic and bio-assimilable, are the most prevalent forms in the environment. Some soil micro-organisms play a dominant role and contribute to the natural cycle of selenium. Our study model, Cupriavidus (formerly Ralstonia) metallidurans CH34, a telluric bacterium characteristic of metal-contaminated biotopes, is known to resist selenite by reducing it into elemental selenium, an insoluble and less toxic form of selenium. In order to better understand the mechanisms of selenium reduction in the bacteria, three methods of speciation were combined (XAS (XANES and EXAFS), HPLC-ICP-MS and SDS-PAGEPIXE). They were completed by the direct quantification of selenium accumulated in the bacteria. Speciation analyses highlighted the existence of two mechanisms of reduction of selenium oxides in C. metallidurans CH34. Assimilation transforms selenite and selenate into organic selenium, identified as seleno-methionine and leads to its non-specific incorporation into bacterial proteins (presence of selenious proteins). Detoxication precipitates selenite in nano-particles of elemental selenium. This way of detoxication is not set up after an exposure to selenate although it is nevertheless possible to detect elemental selenium but in very small amount compared to the exposure of selenite. Seleno-diglutathion is detected in bacteria stressed by an exposure to selenate in medium limited in sulphate. Bacteria exposed to selenite accumulate 25 times more selenium than when they are exposed to selenate. The study of mutants resistant to selenite, which do not express the membrane protein DedA, showed that the accumulation of selenium after exposure to selenite is decreased compared with the wild strain meaning probable link between the transport of selenite and the DedA protein. Finally, selenate would use the sulphate permease

  3. Selenium oxyanion inhibition of hydrogenotrophic and acetoclastic methanogenesis

    NARCIS (Netherlands)

    Lenz, M.; Janzen, N.; Lens, P.N.L.

    2008-01-01

    Inhibitory effects of selenite and selenate towards hydrogenotrophic and acetoclastic methanogenesis were evaluated in anaerobic toxicity assays. The 50% inhibitory concentration (IC50) of both selenium oxyanions was below 6.1 X 10(-5) M in hydrogenotrophic assays, whereas acetoclastic methanogens

  4. Bioprocessing of seleno-oxyanions and tellurite in a novel Bacillus sp. strain STG-83: A solution to removal of toxic oxyanions in presence of nitrate

    International Nuclear Information System (INIS)

    Soudi, Mohammad Reza; Ghazvini, Parisa Tajer Mohammad; Khajeh, Khosro; Gharavi, Sara

    2009-01-01

    Bioremediation of toxic nonmetal and metalloid oxyanions is of great interest. In this study, among 148 bacterial isolates from two types of polluted water, strain STG-83 showed maximum oxyanion reduction and resistance ability. Sequencing of the 16S rDNA gene of STG-83 showed that the strain is closely related to Bacillus pumilus and morphological and biochemical tests confirmed the result. The strain was nitrate negative, but it could reduce half of tellurite in solution containing 1-mM concentration and completely reduced selenite and selenate in solutions containing 1-mM concentrations. Both reduction to elemental form and volatilization occurred in case of all oxyanions tested, according to hydride generation atomic absorption spectroscopy and proton induced X-ray emission analytical methods. The strain was able to tolerate remarkably high concentrations of selenite (640 mM), selenate (320 mM), and tellurite (1250 μM); and tolerance to tellurite increased in presence of selenite and selenate. Biochemical tests and zymogram of extracted culture solutions on gel electrophoresis showed that the strain was nitrate negative and therefore nitrate did not interfere with reduction of other oxyanions. Thus, the strain opens up good opportunities for the bioremediation of polluted waters in natural environment, since nitrate usually inhibits or decelerates reduction of the mentioned toxic oxyanions.

  5. Bioprocessing of seleno-oxyanions and tellurite in a novel Bacillus sp. strain STG-83: a solution to removal of toxic oxyanions in presence of nitrate.

    Science.gov (United States)

    Soudi, Mohammad Reza; Ghazvini, Parisa Tajer Mohammad; Khajeh, Khosro; Gharavi, Sara

    2009-06-15

    Bioremediation of toxic nonmetal and metalloid oxyanions is of great interest. In this study, among 148 bacterial isolates from two types of polluted water, strain STG-83 showed maximum oxyanion reduction and resistance ability. Sequencing of the 16S rDNA gene of STG-83 showed that the strain is closely related to Bacillus pumilus and morphological and biochemical tests confirmed the result. The strain was nitrate negative, but it could reduce half of tellurite in solution containing 1-mM concentration and completely reduced selenite and selenate in solutions containing 1-mM concentrations. Both reduction to elemental form and volatilization occurred in case of all oxyanions tested, according to hydride generation atomic absorption spectroscopy and proton induced X-ray emission analytical methods. The strain was able to tolerate remarkably high concentrations of selenite (640 mM), selenate (320 mM), and tellurite (1250 microM); and tolerance to tellurite increased in presence of selenite and selenate. Biochemical tests and zymogram of extracted culture solutions on gel electrophoresis showed that the strain was nitrate negative and therefore nitrate did not interfere with reduction of other oxyanions. Thus, the strain opens up good opportunities for the bioremediation of polluted waters in natural environment, since nitrate usually inhibits or decelerates reduction of the mentioned toxic oxyanions.

  6. Effects of selenium oxyanions on the white-rot fungus Phanerochaete chrysosporium

    KAUST Repository

    Espinosa-Ortiz, Erika J.

    2014-10-24

    The ability of Phanerochaete chrysosporium to reduce the oxidized forms of selenium, selenate and selenite, and their effects on the growth, substrate consumption rate, and pellet morphology of the fungus were assessed. The effect of different operational parameters (pH, glucose, and selenium concentration) on the response of P. chrysosporium to selenium oxyanions was explored as well. This fungal species showed a high sensitivity to selenium, particularly selenite, which inhibited the fungal growth and substrate consumption when supplied at 10 mg L−1 in the growth medium, whereas selenate did not have such a strong influence on the fungus. Biological removal of selenite was achieved under semi-acidic conditions (pH 4.5) with about 40 % removal efficiency, whereas less than 10 % selenium removal was achieved for incubations with selenate. P. chrysosporium was found to be a selenium-reducing organism, capable of synthesizing elemental selenium from selenite but not from selenate. Analysis with transmission electron microscopy, electron energy loss spectroscopy, and a 3D reconstruction showed that elemental selenium was produced intracellularly as nanoparticles in the range of 30–400 nm. Furthermore, selenite influenced the pellet morphology of P. chrysosporium by reducing the size of the fungal pellets and inducing their compaction and smoothness.

  7. On scandium selenites

    International Nuclear Information System (INIS)

    Znamenskaya, A.S.; Komissarova, L.N.; Petrov, K.I.

    1979-01-01

    Using the methods of IR and PMR spectroscopy the structures of Sc 2 O(SeO 3 )x3H 2 O, Sc 2 (SeO 3 ) 3 x5H 2 O, ScH(SeO 3 ) 2 xH 2 O, Sc(HSeO 3 ) 3 and Sc 2 (Se 2 O 5 ) 3 are investigated. OH-groups are absent in the composition of the main selenite. Acid proton in ScH(SeO 3 ) 2 xH 2 O is delocalized and belongs to both selenite groups, and Sc(HSeO 3 ) 3 presents typical compound with acid stable anion. Distortion degree of SeO 3 group depends on the composition of compounds and differences in their coordination grow with the increase of their number. For scandium pyroselenite the presence of bridge group Se-O-Se is characteristic. Deuteration of the compounds showed that the band in the range of 500 cm -1 belongs to oscillation as to the bound Sc-O. As a result of coordination bond formation and also proton addition the symmetry of SeO 3 group is reduced. Scandium complex selenites MSc(SeO 3 ) 2 xH 2 O are built according to the type ScH(SeO 3 ) 2 xH 2 O. For all the compounds the presence of hydrogen bonds is characteristic except for Sc 2 (Se 2 O 5 ) 3

  8. Nanomembrane Canister Architectures for the Visualization and Filtration of Oxyanion Toxins with One-Step Processing.

    Science.gov (United States)

    Aboelmagd, Ahmed; El-Safty, Sherif A; Shenashen, Mohamed A; Elshehy, Emad A; Khairy, Mohamed; Sakaic, Masaru; Yamaguchi, Hitoshi

    2015-11-01

    Nanomembrane canister-like architectures were fabricated by using hexagonal mesocylinder-shaped aluminosilica nanotubes (MNTs)-porous anodic alumina (PAA) hybrid nanochannels. The engineering pattern of the MNTs inside a 60 μm-long membrane channel enabled the creation of unique canister-like channel necks and cavities. The open-tubular canister architecture design provides controllable, reproducible, and one-step processing patterns of visual detection and rejection/permeation of oxyanion toxins such as selenite (SeO3(2-)) in aquatic environments (i.e., in ground and river water sources) in the Ibaraki Prefecture of Japan. The decoration of organic ligand moieties such as omega chrome black blue (OCG) into inorganic Al2O3@tubular SiO2/Al2O3 canister membrane channel cavities led to the fabrication of an optical nanomembrane sensor (ONS). The OCG ligand was not leached from the canister as observed in washing, sensing, and recovery assays of selenite anions in solution, which enabled its multiple reuse. The ONS makes a variety of alternate processing analyses of selective quantification, visual detection, rejection/permeation, and recovery of toxic selenite quick and simple without using complex instrumentation. Under optimal conditions, the ONS canister exhibited a high selectivity toward selenite anions relative to other ions and a low-level detection limit of 0.0093 μM. Real analytical data showed that approximately 96% of SeO3(2-) anions can be recovered from aquatic and wastewater samples. The ONS canister holds potential for field recovery applications of toxic selenite anions from water. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Reduction of chalcogen oxyanions and generation of nanoprecipitates by the photosynthetic bacterium Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Borghese, Roberto, E-mail: roberto.borghese@unibo.it [Department of Pharmacy and Biotechnology, University of Bologna (Italy); Baccolini, Chiara; Francia, Francesco [Department of Pharmacy and Biotechnology, University of Bologna (Italy); Sabatino, Piera [Department of Chemistry G. Ciamician, University of Bologna (Italy); Turner, Raymond J. [Department of Biological Sciences, University of Calgary, Calgary, Alberta (Canada); Zannoni, Davide, E-mail: davide.zannoni@unibo.it [Department of Pharmacy and Biotechnology, University of Bologna (Italy)

    2014-03-01

    Graphical abstract: - Highlights: • R. capsulatus cells produce extracellular chalcogens nanoprecipitates when lawsone is present. • Lawsone acts as a redox mediator from reducing equivalents to tellurite and selenite. • Nanoprecipitates production depends on carbon source and requires metabolically active cells. • Te{sup 0} and Se{sup 0} nanoprecipitates are identified by X-ray diffraction (XRD) spectroscopy. - Abstract: The facultative photosynthetic bacterium Rhodobacter capsulatus is characterized in its interaction with the toxic oxyanions tellurite (Te{sup IV}) and selenite (Se{sup IV}) by a highly variable level of resistance that is dependent on the growth mode making this bacterium an ideal organism for the study of the microbial interaction with chalcogens. As we have reported in the past, while the oxyanion tellurite is taken up by R. capsulatus cells via acetate permease and it is reduced to Te{sup 0} in the cytoplasm in the form of splinter-like black intracellular deposits no clear mechanism was described for Se{sup 0} precipitation. Here, we present the first report on the biotransformation of tellurium and selenium oxyanions into extracellular Te{sup 0} and Se{sup 0}nanoprecipitates (NPs) by anaerobic photosynthetically growing cultures of R. capsulatus as a function of exogenously added redox-mediator lawsone, i.e. 2-hydroxy-1,4-naphthoquinone. The NPs formation was dependent on the carbon source used for the bacterial growth and the rate of chalcogen reduction was constant at different lawsone concentrations, in line with a catalytic role for the redox mediator. X-ray diffraction (XRD) analysis demonstrated the Te{sup 0} and Se{sup 0} nature of the nanoparticles.

  10. Uptake mechanisms of selenium oxyanions during the ferrihydrite-hematite recrystallization

    Science.gov (United States)

    Börsig, Nicolas; Scheinost, Andreas C.; Shaw, Samuel; Schild, Dieter; Neumann, Thomas

    2017-06-01

    Se is an essential nutrient at trace levels, but also a toxic environmental contaminant at higher concentrations. The mobility of the trace element Se in natural environments is mainly controlled by the occurrence of the highly soluble Se oxyanions - selenite [Se(IV)] and selenate [Se(VI)] - and their interaction with geological materials. Since iron oxides are ubiquitous in nature, many previous studies investigated Se retention by adsorption onto iron oxides. However, little is known about the retention of Se oxyanions during the formation process of iron oxides. In this paper, we therefore studied the immobilization of Se oxyanions during the crystallization of hematite from ferrihydrite. In coprecipitation studies, hematite was synthesized by the precipitation and aging of ferrihydrite in an oxidized Se(IV)- or Se(VI)-containing system (pH 7.5). Hydrochemical data of these batch experiments revealed the complete uptake of all available Se(IV) up to initial concentrations of c(Se)0 = 10-3 mol/L (m/V ratio = 9.0 g/L), while the retention of Se(VI) was low (max. 15% of c(Se)0). In case of high initial Se(IV) concentrations, the results also demonstrated that the interaction of Se with ferrihydrite can affect the type of the final transformation product. Comparative adsorption studies, performed at identical conditions, allowed a distinction between pure adsorption and coprecipitation and showed a significantly higher Se retention by coprecipitation than by adsorption. Desorption studies indicated that Se coprecipitation leads to the occurrence of a resistant, non-desorbable Se fraction. According to time-resolved studies of Se(IV) or Se(VI) retention during the hematite formation and detailed spectroscopic analyses (XPS, XAS), this fraction is the result of an incorporation process, which is not attributable to Fe-for-Se substitution or the Se occupation of vacancies. Se initially adsorbs to the ferrihydrite surface, but after the transformation of ferrihydrite

  11. Reduction of chromate and carotene-synthesizing activity of selenite-resistant mutants of the yeast Xanthophyllomyces dendrorhous (Phaffia rhodozyma

    Directory of Open Access Journals (Sweden)

    Grzàdka M.

    2009-08-01

    Full Text Available Aim. The yeast P. rhodozyma is a perspective microbial producer of carotenoid pigment astaxanthin with a high antioxidant power. The aim of the work was to study the ability of the selenite-resistant strains of this yeast to reduce chrome(VI compounds, as well as to analyze the relations between synthesis of carotenoids, resistance to selenite and chromate-reducing activity of P. rhodozyma. Methods. The yeast cells were grown at standard conditions for this species. The residual chromate content in cultural liquid was determined colorimetrically using diphenylcarbazide. The carotenoid content was determined after extraction of the pigments from the previously permeabilized cells by organic solvents. Results. The selected selenite-resistant mutants of the yeast P. rhodozyma revealed the different combinations of the phenotypes related with tolerance/sensitivity to chromate and selenite, as well as ability to reduce chromate. Conclusions. The obtained results give reasons for suggesting that pathways of detoxification of chromate and selenite by the yeast P. rhodozyma are different, although run through a common reductive type. The isolated mutant strains would be served as the useful models to study relations between homeostasis of Se and Cr oxyanions and biosynthesis of carotenes.

  12. Formation of Se(0), Te(0), and Se(0)-Te(0) nanostructures during simultaneous bioreduction of selenite and tellurite in a UASB reactor.

    Science.gov (United States)

    Wadgaonkar, Shrutika L; Mal, Joyabrata; Nancharaiah, Yarlagadda V; Maheshwari, Neeraj O; Esposito, Giovanni; Lens, Piet N L

    2018-03-01

    Simultaneous removal of selenite and tellurite from synthetic wastewater was achieved through microbial reduction in a lab-scale upflow anaerobic sludge blanket reactor operated with 12 h hydraulic retention time at 30 °C and pH 7 for 120 days. Lactate was supplied as electron donor at an organic loading rate of 528 or 880 mg COD L -1  day -1 . The reactor was initially fed with a synthetic influent containing 0.05 mM selenite and tellurite each (phase I, day 1-60) and subsequently with 0.1 mM selenite and tellurite each (phase II, day 61-120). At the end of phase I, selenite and tellurite removal efficiencies were 93 and 96%, respectively. The removal percentage dropped to 87 and 81% for selenite and tellurite, respectively, at the beginning of phase II because of the increased influent concentrations. The removal efficiencies of both selenite and tellurite were gradually restored within 20 days and stabilized at ≥ 97% towards the end of the experiment. Powder X-ray diffraction and Raman spectroscopy confirmed the formation of biogenic Se(0), Te(0), and Se(0)-Te(0) nanostructures. Scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy showed aggregates comprising of Se(0), Te(0), and Se-Te nanostructures embedded in a layer of extracellular polymeric substances (EPS). Infrared spectroscopy confirmed the presence of chemical signatures of the EPS which capped the nanoparticle aggregates that had been formed and immobilized in the granular sludge. This study suggests a model for technologies for remediation of effluents containing Se and Te oxyanions coupled with biorecovery of bimetal(loid) nanostructures.

  13. Toxicity and accumulation of selenite in four microalgae

    Science.gov (United States)

    Wang, Dazhi; Cheng, Zhaodi; Li, Shaojing; Gao, Yahui

    2003-09-01

    The toxicity and bioaccumulation of selenite in four microalgae, Spirulina platensis, Dunaliella salina, Dunaliella bardawill and Phaeodactylum tricornutum cultured in the presence of selenite were investigated. Lower concentrations of selenite were generally nontoxic and frequently stimulated algal growth, while higher concentrations of selenite inhibited algal growth. Selenite was more toxic to D. salina and D. bardawill than to S. platensis and P. Tricornutum. All algae cultured in selenite were able to incorporate Se to different degrees, which depended on algal species. The distributions of selenite among intracellular macromolecular compounds were different among algal species: most of the selenite was associated with proteins in S. platensis, D. salina and D. bardawill, while most of the selenite was associated with lipids in P. tricornutum, which reflected the physiological differences among the algae. These observations suggest that algae are able to accumulate selenite and bind it with intracellular macromolecular compounds when exposed to high concentration of selenite. This may represent a form of storage or detoxification of selenite by the algae.

  14. Short range order of selenite glasses

    Czech Academy of Sciences Publication Activity Database

    Neov, S.; Gerasimova, I.; Yordanov, S.; Lakov, L.; Mikula, Pavol; Lukáš, Petr

    1999-01-01

    Roč. 40, č. 2 (1999), s. 111-112 ISSN 0031-9090 R&D Projects: GA AV ČR KSK1010104 Keywords : short range * selenite glasses Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.822, year: 1999

  15. Bacterial PerO Permeases Transport Sulfate and Related Oxyanions.

    Science.gov (United States)

    Hoffmann, Marie-Christine; Pfänder, Yvonne; Tintel, Marc; Masepohl, Bernd

    2017-07-15

    Rhodobacter capsulatus synthesizes the high-affinity ABC transporters CysTWA and ModABC to specifically import the chemically related oxyanions sulfate and molybdate, respectively. In addition, R. capsulatus has the low-affinity permease PerO acting as a general oxyanion transporter, whose elimination increases tolerance to molybdate and tungstate. Although PerO-like permeases are widespread in bacteria, their function has not been examined in any other species to date. Here, we present evidence that PerO permeases from the alphaproteobacteria Agrobacterium tumefaciens , Dinoroseobacter shibae , Rhodobacter sphaeroides , and Sinorhizobium meliloti and the gammaproteobacterium Pseudomonas stutzeri functionally substitute for R. capsulatus PerO in sulfate uptake and sulfate-dependent growth, as shown by assimilation of radioactively labeled sulfate and heterologous complementation. Disruption of perO genes in A. tumefaciens , R. sphaeroides , and S. meliloti increased tolerance to tungstate and, in the case of R. sphaeroides , to molybdate, suggesting that heterometal oxyanions are common substrates of PerO permeases. This study supports the view that bacterial PerO permeases typically transport sulfate and related oxyanions and, hence, form a functionally conserved permease family. IMPORTANCE Despite the widespread distribution of PerO-like permeases in bacteria, our knowledge about PerO function until now was limited to one species, Rhodobacter capsulatus In this study, we showed that PerO proteins from diverse bacteria are functionally similar to the R. capsulatus prototype, suggesting that PerO permeases form a conserved family whose members transport sulfate and related oxyanions. Copyright © 2017 American Society for Microbiology.

  16. Sodium selenite as a new rodenticide

    Directory of Open Access Journals (Sweden)

    Goran Jokić

    2014-09-01

    Full Text Available Rodents are the most destructive group of small mammalian pests considering the overall damage that they cause by feeding and other activities, or as vectors of many disease agents. In practice, chemical rodenticides have been the most widespread and most effective method of control of commensal (Mus musculus, Rattus norvegicus and R. rattus and most harmful field rodent pests (Apodemus sylvaticus, A. agrarius and Microtus arvalis. After anticoagulant and vitamin D3 rodenticides, which were introduced worldwide in the 1980s, no other chemical compound has had a comparable role as a rodenticide in practice. In the past decade, commercial baits containing 0.1% sodium selenite have also been registered in Serbia in various formulations both for controlling rodents indoors and in the field. Data on sodium selenite as a rodenticide have been scarce. The present paper surveys research data reported so far, analyzing and drawing conclusions regarding the validity and feasibility of sodium selenite as a method of rodent control with reference to the available ecotoxicological data.

  17. Towards a selective adsorbent for arsenate and selenite in the presence of phosphate: Assessment of adsorption efficiency, mechanism, and binary separation factors of the chitosan-copper complex.

    Science.gov (United States)

    Yamani, Jamila S; Lounsbury, Amanda W; Zimmerman, Julie B

    2016-01-01

    The potential for a chitosan-copper polymer complex to select for the target contaminants in the presence of their respective competitive ions was evaluated by synthesizing chitosan-copper beads (CCB) for the treatment of (arsenate:phosphate), (selenite:phosphate), and (selenate:sulfate). Based on work by Rhazi et al., copper (II) binds to the amine moiety on the chitosan backbone as a monodentate complex (Type I) and as a bidentate complex crosslinking two polymer chains (Type II), depending on pH and copper loading. In general, the Type I complex exists alone; however, beyond threshold conditions of pH 5.5 during synthesis and a copper loading of 0.25 mol Cu(II)/mol chitosan monomer, the Type I and Type II complexes coexist. Subsequent chelation of this chitosan-copper ligand to oxyanions results in enhanced and selective adsorption of the target contaminants in complex matrices with high background ion concentrations. With differing affinities for arsenate, selenite, and phosphate, the Type I complex favors phosphate chelation while the Type II complex favors arsenate chelation due to electrostatic considerations and selenite chelation due to steric effects. No trend was exhibited for the selenate:sulfate system possibly due to the high Ksp of the corresponding copper salts. Binary separation factors, α12, were calculated for the arsenate-phosphate and selenite-phosphate systems, supporting the mechanistic hypothesis. While, further research is needed to develop a synthesis method for the independent formation of the Type II complexes to select for target contaminants in complex matrices, this work can provide initial steps in the development of a selective adsorbent. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Reaction of aluminium selenites with alkali metal selenites in hydrothermal conditions

    International Nuclear Information System (INIS)

    Tananaev, I.V.; Volodina, A.N.; Bol'shakova, N.K.; Petrov, K.I.

    1976-01-01

    In the course of hydrothermal crystallization (T from 150 deg to 200 deg C, P=20 atm) of Al 2 (SeO 3 ) 3 x6H 2 O in solutions of cesium and rubidium trihydroselenites, which contain an excess of the alkali metals, there form the isostructural mixed selenites Cssub(0.5)Hsub(0.5)Al(SeO 3 ) 2 xH 2 O and Rbsub(0.6)Hsub(0.4)Al(SeO 3 ) 2 x2H 2 O. Under the same conditions, in the solutions of lithium, sodium and potassium trihydroselenites, Al 2 (SeO 3 ) 3 x6H 2 O fails to form the mixed selenites. The IR-spectroscopic study of the mixed selenites Al has been carried out and their thermal decomposition has been investigated. The obtained data make it possible to represent the mixed selenites by the formula Msub(x)Hsub(1-x)Al(SeO 3 ) 2 xnH 2 O and to regard them as compounds of variable composition [ru

  19. Minimal transition state charge stabilization of the oxyanion during peptide bond formation by the ribosome.

    Science.gov (United States)

    Carrasco, Nicolas; Hiller, David A; Strobel, Scott A

    2011-12-06

    Peptide bond formation during ribosomal protein synthesis involves an aminolysis reaction between the aminoacyl α-amino group and the carbonyl ester of the growing peptide via a transition state with a developing negative charge, the oxyanion. Structural and molecular dynamic studies have suggested that the ribosome may stabilize the oxyanion in the transition state of peptide bond formation via a highly ordered water molecule. To biochemically investigate this mechanistic hypothesis, we estimated the energetic contribution to catalytic charge stabilization of the oxyanion using a series of transition state mimics that contain different charge distributions and hydrogen bond potential on the functional group mimicking the oxyanion. Inhibitors containing an oxyanion mimic that carried a neutral charge and a mimic that preserved the negative charge but could not form hydrogen bonds had less than a 3-fold effect on inhibitor binding affinity. These observations argue that the ribosome provides minimal transition state charge stabilization to the oxyanion during peptide bond formation via the water molecule. This is in contrast to the substantial level of oxyanion stabilization provided by serine proteases. This suggests that the oxyanion may be neutralized via a proton shuttle, resulting in an uncharged transition state.

  20. 40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting under...

  1. Differential diagnosis of scintigraphic brain centres by 75Se selenite

    International Nuclear Information System (INIS)

    Bestagno, M.; Garraffa, V.; Rembado, R.; Guerra, U.

    1975-01-01

    Since standard brain scintigraphy with sup(99m)Tc is not always adequate for a satisfactory differential diagnosis of the radioactive foci detected, the possibilities of 75 Se sodium selenite were investigated. It was observed that in centres due to a vascular lesion the selenite concentration is always low, rising steeply in neoplasmic foci. The 75 Se-selenite scintigraphic method is considered highly valid, complementing that of sup(99m)Tc when this latter is unsuitable for diagnosis of the nature of cerebral foci [fr

  2. Selenite Reduction by Anaerobic Microbial Aggregates: Microbial Community Structure, and Proteins Associated to the Produced Selenium Spheres

    KAUST Repository

    Gonzalez-Gil, Graciela

    2016-04-26

    Certain types of anaerobic granular sludge, which consists of microbial aggregates, can reduce selenium oxyanions. To envisage strategies for removing those oxyanions from wastewater and recovering the produced elemental selenium (Se0), insights into the microbial community structure and synthesis of Se0 within these microbial aggregates are required. High-throughput sequencing showed that Veillonellaceae (c.a. 20%) and Pseudomonadaceae (c.a.10%) were the most abundant microbial phylotypes in selenite reducing microbial aggregates. The majority of the Pseudomonadaceae sequences were affiliated to the genus Pseudomonas. A distinct outer layer (∼200 μm) of selenium deposits indicated that bioreduction occurred in the outer zone of the microbial aggregates. In that outer layer, SEM analysis showed abundant intracellular and extracellular Se0 (nano)spheres, with some cells having high numbers of intracellular Se0 spheres. Electron tomography showed that microbial cells can harbor a single large intracellular sphere that stretches the cell body. The Se0 spheres produced by the microorganisms were capped with organic material. X-ray photoelectron spectroscopy (XPS) analysis of extracted Se0 spheres, combined with a mathematical approach to analyzing XPS spectra from biological origin, indicated that proteins and lipids were components of the capping material associated to the Se0 spheres. The most abundant proteins associated to the spheres were identified by proteomic analysis. Most of the proteins or peptide sequences capping the Se0 spheres were identified as periplasmic outer membrane porins and as the cytoplasmic elongation factor Tu protein, suggesting an intracellular formation of the Se0 spheres. In view of these and previous findings, a schematic model for the synthesis of Se0 spheres by the microorganisms inhabiting the granular sludge is proposed.

  3. Nitric oxide-cytokinin interplay influences selenite sensitivity in Arabidopsis.

    Science.gov (United States)

    Lehotai, Nóra; Feigl, Gábor; Koós, Ágnes; Molnár, Árpád; Ördög, Attila; Pető, Andrea; Erdei, László; Kolbert, Zsuzsanna

    2016-10-01

    Selenite oppositely modifies cytokinin and nitric oxide metabolism in Arabidopsis organs. A mutually negative interplay between the molecules exists in selenite-exposed roots; and their overproduction causes selenite insensitivity. Selenium-induced phytotoxicity is accompanied by developmental alterations such as primary root (PR) shortening. Growth changes are provoked by the modulation of hormone status and signalling. Cytokinin (CK) cooperates with the nitric oxide (NO) in many aspects of plant development; however, their interaction under abiotic stress has not been examined. Selenite inhibited the growth of Arabidopsis seedlings and reduced root meristem size through cell division arrest. The CK-dependent pARR5::GUS activity revealed the intensification of CK signalling in the PR tip, which may be partly responsible for the root meristem shortening. The selenite-induced alterations in the in situ expressions of cytokinin oxidases (AtCKX4::GUS, AtCKX5::GUS) are associated with selenite-triggered changes of CK signalling. In wild-type (WT) and NO-deficient nia1nia2 root, selenite led to the diminution of NO content, but CK overproducer ipt-161 and -deficient 35S:CKX2 roots did not show NO decrease. Exogenous NO (S-nitroso-N-acetyl-DL-penicillamine, SNAP) reduced the pARR5::GFP and pTCS::GFP expressions. Roots of the 35S:CKX and cyr1 plants suffered more severe selenite-triggered viability loss than the WT, while in ipt-161 and gsnor1-3 no obvious viability decrease was observed. Exogenous NO ameliorated viability loss, but benzyladenine intensified it. Based on the results, selenite impacts development by oppositely modifying CK signalling and NO level. In the root system, CK signalling intensifies which possibly contributes to the nitrate reductase-independent NO diminution. A mutually negative CK-NO interplay exists in selenite-exposed roots; however, overproduction of both molecules worsens selenite sensing. Hereby, we suggest novel regulatory interplay and

  4. Bioreduction of Selenium Oxyanions via the Feammox Process

    Science.gov (United States)

    Sherman, A.; Jaffe, P. R.

    2017-12-01

    Selenium (Se) is an important environmental contaminant found in both agricultural and industrial wastewater. A novel bacterium, Acidimicrobiaceae bacterium A6 (hereon referred to as A6), has been shown to oxidize ammonium through the reduction of iron oxides (termed the Feammox process) and has also been shown to reduce trace metals and radionuclides. This research aims to establish whether the Feammox process can be used to reduce Se oxyanions in wastewater, and to determine the pathway by which this reduction occurs. A novel method of Se analysis using ion chromatography (Dionex Aquion IC system, AS18 separator and guard columns, 18mM KOH eluent, 45mA) has been developed, showing clear resolution of SeO32- and SeO42- peaks and detection limits in the ppb range. Batch incubations were run using pure A6 culture to tie the reduction of Se to the activity of this bacterium. Nontronite was used as the iron source to sustain A6 activity. Unlike other iron sources, such as ferrihydrite, nontronite does not sorb Se oxyanions, and thus selenium remains bioavailable as an electron acceptor for use during the Feammox process. Concentrations of 1ppm of SeO32- and SeO42- were used, below the toxic threshold for A6, and incubations were sampled destructively over the course of 8 days. Samples were analyzed using ion chromatography and UV-Vis spectroscopy to determine bacterial activity and chemical speciation. Initial results indicate that A6 may be able to reduce 300ppb of SeO32-in 3 days, however more work is needed to further explain this result.

  5. Comparative study of Se oxyanions retention on three argillaceous rocks: Upper Toarcian (Tournemire, France), Black Shales (Tournemire, France) and Opalinus Clay (Mont Terri, Switzerland).

    Science.gov (United States)

    Frasca, B; Savoye, S; Wittebroodt, C; Leupin, O X; Michelot, J-L

    2014-01-01

    A comparative study of selenium oxyanion sorption was carried out by means of batch sorption experiments on three argillaceous rocks that differ in their mineralogical compositions and textural properties. The results show no selenate (Se(VI)) sorption onto the argillaceous rocks after 60 days, but clear sorption of selenite (Se(IV)), the extent being closely related to the initial Se(IV) concentration. At the lowest concentration ([Se(IV)]eq rock affinity for Se(IV) is Black Shales > Opalinus Clay (OPA) > Upper Toarcian, with Rd values of 910 ± 70, 600 ± 65 and 470 ± 70 mL g(-1) respectively. The Se(IV) sorption isotherms acquired for the three argillaceous rocks can be reproduced well by means of Langmuir formalism, particularly with a two-site Langmuir model. The comparison of the Se(IV) sorption isotherms obtained for these three rocks led to identification of pyrite associated with natural organic matter (NOM) as one of the main phases involved in selenium retention. While the desorption results suggested a significant Se(IV) reduction in the Upper Toarcian samples, the reversible sorption shown on the Black Shales and OPA samples was correlated with a sulfate increase, symptomatic of surface oxidation of pyrite which could limit the Se(IV) reduction in favor of sorption. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. The mechanism of interaction between cisplatin and selenite

    NARCIS (Netherlands)

    Baldew, G S; Mol, J G; de Kanter, F J; van Baar, B; De Goeij, J J; Vermeulen, N P

    1991-01-01

    Cisplatin is a widely used antitumor drug, highly effective in the treatment of several tumors. Cisplatin exerts its antitumor activity through an interaction with DNA, which results in the formation of bidentate adducts. An important side-effects of cisplatin is nephrotoxicity. Selenite can reduce

  7. A rhizobium selenitireducens protein showing selenite reductase activity

    Science.gov (United States)

    Biobarriers remove, via precipitation, the metalloid selenite (SeO3–2) from groundwater; a process that involves the biological reduction of soluble SeO3–2 to insoluble elemental red selenium (Se0). The enzymes associated with this reduction process are poorly understood. In Rhizobium selenitiredu...

  8. FTIR spectroscopic studies of selenite reduction by cells of the rhizobacterium Azospirillum brasilense Sp7 and the formation of selenium nanoparticles

    Science.gov (United States)

    Kamnev, Alexander A.; Mamchenkova, Polina V.; Dyatlova, Yulia A.; Tugarova, Anna V.

    2017-07-01

    Microbially driven reduction of selenium oxyanions to elementary selenium, often in the form of nanoparticles (NPs), is widespread in nature. A diversity of possible applications of such biogenic NPs, including those in nanobiotechnology, as well as the specificity of methodologies and mechanisms of their formation via ;green synthesis; are very attractive features justifying further studies of the processes of selenium oxyanion bioreduction and the resulting Se0 nanostructures. In this study, live biomass of the rhizobacterium Azospirillum brasilense Sp7 (harvested after the logarithmic growth phase and washed from culture medium components) was used to obtain extracellular Se NPs relatively homogeneous in size (with average diameters within 50-100 nm) in the process of selenite reduction. Both the control cultures of A. brasilense Sp7 and those incubated with SeO32- (producing Se NPs), as well as the resulting separated Se NPs were studied using Fourier transform infrared (FTIR) spectroscopy in the transmission mode (measured as dried layers on a ZnSe disc), in addition to transmission electron microscopy (TEM), to compare metabolic changes in cells and the bioorganic layers associated with the Se NPs. In the control culture (stored for 24 h in physiological saline), FTIR spectroscopic signs of poly-3-hydroxybutyrate (a 'reserve' biopolyester) were observed as a response to the lack of nutrients (trophic stress), whereas they were virtually absent in cells incubated for 24 h in physiological saline with 10 mM SeO32- (toxicity stress). FTIR spectra of Se NPs separated from bacterial cells showed bands typical of proteins, polysaccharides and lipids associated with the particles (in line with their TEM images showing a thin layer over the NPs), in addition to strong carboxylate bands, which evidently stabilise the NP structure and morphology.

  9. Subventions aux institutions

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    voir comment votre projet évolue eu égard à la recherche et aux aspects administratifs et financiers. Le CRDI sait bien que des problèmes peuvent surgir durant l'exécution des projets et reconnaît que les institutions qu'il finance appliquent des systèmes de comptabilité et des modalités administratives qui diffèrent des ...

  10. Pseudomonas moraviensis subsp. stanleyae, a bacterial endophyte of hyperaccumulator Stanleya pinnata, is capable of efficient selenite reduction to elemental selenium under aerobic conditions.

    Science.gov (United States)

    Staicu, L C; Ackerson, C J; Cornelis, P; Ye, L; Berendsen, R L; Hunter, W J; Noblitt, S D; Henry, C S; Cappa, J J; Montenieri, R L; Wong, A O; Musilova, L; Sura-de Jong, M; van Hullebusch, E D; Lens, P N L; Reynolds, R J B; Pilon-Smits, E A H

    2015-08-01

    To identify bacteria with high selenium tolerance and reduction capacity for bioremediation of wastewater and nanoselenium particle production. A bacterial endophyte was isolated from the selenium hyperaccumulator Stanleya pinnata (Brassicaceae) growing on seleniferous soils in Colorado, USA. Based on fatty acid methyl ester analysis and multi-locus sequence analysis (MLSA) using 16S rRNA, gyrB, rpoB and rpoD genes, the isolate was identified as a subspecies of Pseudomonas moraviensis (97.3% nucleotide identity) and named P. moraviensis stanleyae. The isolate exhibited extreme tolerance to SeO3(2-) (up to 120 mmol l(-1)) and SeO4(2-) (>150 mmol l(-1)). Selenium oxyanion removal from growth medium was measured by microchip capillary electrophoresis (detection limit 95 nmol l(-1) for SeO3(2-) and 13 nmol l(-1) for SeO4(2-)). Within 48 h, P. moraviensis stanleyae aerobically reduced SeO3(2-) to red Se(0) from 10 mmol l(-1) to below the detection limit (removal rate 0.27 mmol h(-1) at 30 °C); anaerobic SeO3(2-) removal was slower. No SeO4(2-) removal was observed. Pseudomonas moraviensis stanleyae stimulated the growth of crop species Brassica juncea by 70% with no significant effect on Se accumulation. Pseudomonas moraviensis stanleyae can tolerate extreme levels of selenate and selenite and can deplete high levels of selenite under aerobic and anaerobic conditions. Pseudomonas moraviensis subsp. stanleyae may be useful for stimulating plant growth and for the treatment of Se-laden wastewater. © 2015 The Society for Applied Microbiology.

  11. The response of three aquatic plants to different concentration od selenite in media

    OpenAIRE

    Mohorko, Evelina

    2013-01-01

    The response of three aquatic plants (Myriophyllum spicatum, Ceratophyllum demersum and Potamogeton perfoliatus) to the change in selenite content in their environment was studied. All chosen aquatic plants were at first exposed to the medium with 10 mg/L of added selenite for various days of exposure (1 to 15 days). After the treatments the plants were transplanted to medium without added selenite for 5 days. After each treatment the photochemical efficiency of photosystem II (PS II), electr...

  12. Selenite reduction and ammoniacal nitrogen removal in an aerobic granular sludge sequencing batch reactor.

    Science.gov (United States)

    Nancharaiah, Y V; Sarvajith, M; Lens, P N L

    2017-12-14

    Simultaneous removal of selenite and ammonium by aerobic granular sludge was investigated to develop an improved biological treatment process for selenium rich wastewaters. Aerobic granules not previously exposed to selenite were able to remove selenite by converting it to elemental selenium (Se(0)) and simultaneously remove ammonium under different conditions in batch experiments. To achieve sustainable selenite and ammonium removal, an aerobic granular sludge reactor was operated in fill-and-draw mode with a cycle of anaerobic (8 h) and aeration (15 h) phases. Almost complete removal of different initial concentrations of selenite up to 100 μM was achieved in the anaerobic phase. Ammonium removal was severely inhibited when the granules were initially exposed to 1.27 mg L -1 selenite, but ammonium and total nitrogen removal efficiencies gradually improved to 100 and 98%, respectively, under selenite-reducing conditions. Selenite loading shifted ammonium removal occurring mainly during the anaerobic phase to both the anaerobic and aeration phases. Selenite was removed from the aqueous phase by converting it to nanoparticulate Se(0), which was entrapped in the granular sludge. Scanning electron microscop-energy dispersive X-ray spectroscopy and X-ray diffraction analysis confirmed the formation of Se(0) nanospheres and their retention in the granular sludge. The effluent Se ranged from 0.02 to 0.25 mg Se L -1 , while treating up to 12.7 mg L -1 selenite, which is lower as compared to previous studies on selenite removal using activated sludge or anaerobic granular sludge. This study shows that aerobic granular sludge reactors are not only capable of removing toxic selenite, but offer improved treatment of Se-rich wastewaters. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Metabolism of selenite to selenosugar and trimethylselenonium in vivo

    DEFF Research Database (Denmark)

    Jackson, Matthew I; Lunøe, Kristoffer; Gabel-Jensen, Charlotte

    2013-01-01

    Impaired S-adenosylmethionine (SAM)-dependent transmethylation and methylation capacity feature in diseases related to obesity or aging, and selenium (Se) metabolism is altered in these states. We tested the hypothesis that SAM metabolism is required for methylation and excretion of Se in a rat m...... model. Four hours after selenite and periodate-oxidized adenosine (POA; an inhibitor of SAM metabolism) were administered, circulating markers of single-carbon status were unchanged, except for decreased circulating phosphatidylcholine (P...

  14. Selenite protects Caenorhabditis elegans from oxidative stress via DAF-16 and TRXR-1.

    Science.gov (United States)

    Li, Wen-Hsuan; Shi, Yeu-Ching; Chang, Chun-Han; Huang, Chi-Wei; Hsiu-Chuan Liao, Vivian

    2014-04-01

    Selenium is an essential micronutrient. In the present study, trace amount of selenite (0.01 μM) was evaluated for oxidative stress resistance and potential associated factors in Caenorhabditis elegans. Selenite-treated C. elegans showed an increased survival under oxidative stress and thermal stress compared to untreated controls. Further studies demonstrated that the significant stress resistance of selenite on C. elegans could be attributed to its in vivo free radical-scavenging ability. We also found that the oxidative and thermal stress resistance phenotypes by selenite were absent from the forkhead transcription factor daf-16 mutant worms. Moreover, selenite influenced the subcellular distribution of DAF-16 in C. elegans. Furthermore, selenite increased mRNA levels of stress-resistance-related proteins, including superoxide dismutase-3 and heat shock protein-16.2. Additionally, selenite (0.01 μM) upregulated expressions of transgenic C. elegans carrying sod-3::green fluorescent protein (GFP) and hsp-16.2::GFP, whereas this effect was abolished by feeding daf-16 RNA interference in C. elegans. Finally, unlike the wild-type N2 worms, the oxidative stress resistance phenotypes by selenite were both absent from the C. elegans selenoprotein trxr-1 mutant worms and trxr-1 mutants feeding with daf-16 RNA interference. These findings suggest that the antioxidant effects of selenite in C. elegans are mediated via DAF-16 and TRXR-1. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Pharmacokinetics of selenium after sodium selenite administration to rats

    International Nuclear Information System (INIS)

    Natsuhori, Masahiro; Nagaoka, Tamae; Ito, Nobuhiko

    1998-01-01

    Selenium (Se) concentrations in plasma, urine, and feces were determined by PIXE analysis before and after intravenous (iv) / oral (po) administration of sodium selenite (a dose equivalent to 2 mg/kg of selenium) to rats. The concentration-time profiles of Se were analyzed by a pharmacokinetic approach. The plasma Se profile after iv injection was biphasic and well-fit to a 2-compartment open model, showing two half lives (tl/2). The first tl/2 was about 0.3 hr and the second tl/2 was 6.9 hrs. The plasma concentration reached almost basal level after about 80 hrs of injection. On the other hand, plasma profiles after po administration showed absorption rate-limiting elimination. The bioavailability of oral sodium selenite (about 49%) and significantly higher amount of fecal Se excretion indicated relatively poor intestinal absorption of sodium selenite, compared to the previously published data. Urinary Se excretion was almost comparable between iv and po groups. The total recovery of the dose excreted in urine and feces was 30 ± 10% in iv and 56 ± 15% in po group. The renal excretion was considered to be a major route of Se excretion after absorption. Significant amount of Se that was not fully excreted was noted, suggesting Se distribution or accumulation in organs, together with volatile excretion. (author)

  16. Introduction aux notices

    OpenAIRE

    Calas, Bernard

    2012-01-01

    Construites par des étudiants – géographes comme politistes ou juristes – du Master « Dynamiques africaines », formation pluridisciplinaire commune aux universités de Bordeaux 2, 3 et IV et à l’Institut d’Études politiques de Bordeaux, ces cartes prouvent l’intérêt d’une courte formation (une vingtaine d’heures) pour amener à un niveau de pratique tout à fait honorable et d’un grand intérêt scientifique et performatif. Ces cartes peuvent donc se lire comme des études de cas de conflits africa...

  17. Simultaneous leaching of arsenite, arsenate, selenite and selenate, and their migration in tunnel-excavated sedimentary rocks: II. Kinetic and reactive transport modeling.

    Science.gov (United States)

    Tabelin, Carlito Baltazar; Sasaki, Ryosuke; Igarashi, Toshifumi; Park, Ilhwan; Tamoto, Shuichi; Arima, Takahiko; Ito, Mayumi; Hiroyoshi, Naoki

    2017-12-01

    Predicting the fates of arsenic (As) and selenium (Se) in natural geologic media like rocks and soils necessitates the understanding of how their various oxyanionic species behave and migrate under dynamic conditions. In this study, geochemical factors and processes crucial in the leaching and transport of arsenite (As III ), arsenate (As V ), selenite (Se IV ) and selenate (Se VI ) in tunnel-excavated rocks of marine origin were investigated using microscopic/extraction techniques, column experiments, dissolution-precipitation kinetics and one-dimensional reactive transport modeling. The results showed that evaporite salts were important because aside from containing As and Se, they played crucial roles in the evolution of pH and concentrations of coexisting ions, both of which had strong effects on adsorption-desorption reactions of As and Se species with iron oxyhydroxide minerals/phases. The observed leaching trends of As V , As III , Se IV and Se VI were satisfactorily simulated by one-dimensional reactive transport models, which predict that preferential adsorptions of As V and Se IV were magnified by geochemical changes in the columns due to water flow. Moreover, our results showed that migrations of As III , Se IV and Se VI could be predicted adequately by 1D solute transport with simple activity-K' d approach, but surface complexation was more reliable to simulate adsorption-desorption behavior of As V . Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Extraction and characterization of ternary complexes between natural organic matter, cations, and oxyanions from a natural soil.

    Science.gov (United States)

    Peel, Hannah R; Martin, David P; Bednar, Anthony J

    2017-06-01

    Natural organic matter (NOM) can have a significant influence on the mobility and fate of inorganic oxyanions, such as arsenic and selenium, in the environment. There is evidence to suggest that interactions between NOM and these oxyanions are facilitated by bridging cations (primarily Fe 3+ ) through the formation of ternary complexes. Building on previous work characterizing ternary complexes formed in the laboratory using purified NOM, this study describes the extraction and characterization of intact ternary complexes directly from a soil matrix. The complexes are stable to the basic extraction conditions (pH 12) and do not appear to change when the pH of the extract is adjusted back to neutral. The results suggest that ternary complexes between NOM, cations, and inorganic oxyanions exist in natural soils and could play a role in the speciation of inorganic oxyanions in environmental matrices. Published by Elsevier Ltd.

  19. Aux origines du monde

    CERN Multimedia

    2004-01-01

    "C'est l'histoire d'une aventure humaine, scientifique, international qui a vu le jour il y a cinquante ans, aux confins de la Suisse et du département de l'Ain. Le plus grand laboratoire de physique des particules du monde, le Cern, a été fondé en 1954. Les festivités organisées à l occasion de cet anniversaire connaîtront leur point d'orgue le 16 octobre prochain, avec portes-ouvertes, accueil de personallités et inauguration d'un monumnet spécifique, le Globe de l'innovation" (2 pages)

  20. Modeling selenite adsorption envelopes on oxides, clay minerals, and soils using the triple layer model

    Science.gov (United States)

    Selenite adsorption behavior was investigated on amorphous aluminum and iron oxides, clay minerals: kaolinite, montmorillonite, and illite, and 45 surface and subsurface soil samples from the Southwestern and Midwestern regions of the USA as a function of solution pH. Selenite adsorption decreased ...

  1. Contribution of cutinase serine 42 side chain to the stabilization of the oxyanion transition state.

    Science.gov (United States)

    Nicolas, A; Egmond, M; Verrips, C T; de Vlieg, J; Longhi, S; Cambillau, C; Martinez, C

    1996-01-16

    Cutinase from the fungus Fusarium solani pisi is a lipolytic enzyme able to hydrolyze both aggregated and soluble substrates. It therefore provides a powerful tool for probing the mechanisms underlying lipid hydrolysis. Lipolytic enzymes have a catalytic machinery similar to those present in serine proteinases. It is characterized by the triad Ser, His, and Asp (Glu) residues, by an oxyanion binding site that stabilizes the transition state via hydrogen bonds with two main chain amide groups, and possibly by other determinants. It has been suggested on the basis of a covalently bond inhibitor that the cutinase oxyanion hole may consist not only of two main chain amide groups but also of the Ser42 O gamma side chain. Among the esterases and the serine and the cysteine proteases, only Streptomyces scabies esterase, subtilisin, and papain, respectively, have a side chain residue which is involved in the oxyanion hole formation. The position of the cutinase Ser42 side chain is structurally conserved in Rhizomucor miehei lipase with Ser82 O gamma, in Rhizopus delemar lipase with Thr83 O gamma 1, and in Candida antartica B lipase with Thr40 O gamma 1. To evaluate the increase in the tetrahedral intermediate stability provided by Ser42 O gamma, we mutated Ser42 into Ala. Furthermore, since the proper orientation of Ser42 O gamma is directed by Asn84, we mutated Asn84 into Ala, Leu, Asp, and Trp, respectively, to investigate the contribution of this indirect interaction to the stabilization of the oxyanion hole. The S42A mutation resulted in a drastic decrease in the activity (450-fold) without significantly perturbing the three-dimensional structure. The N84A and N84L mutations had milder kinetic effects and did not disrupt the structure of the active site, whereas the N84W and N84D mutations abolished the enzymatic activity due to drastic steric and electrostatic effects, respectively.

  2. Chronopotentiometry of refractory metals, actinides and oxyanions in molten salts: A review

    Science.gov (United States)

    Bansal, Narottam P.

    1992-01-01

    The applications of chronopotentiometry to the study of electrochemical behavior of three technologically important areas of refractory metals, actinides, and oxyanions in molten salts are critically reviewed. Chronopotentiometry is a very versatile diagnostic tool to understand the reaction mechanism of the electrode processes for the electrochemical reduction/oxidation of these electroactive species in molten salt solutions. Well adherent, compact, and uniformly thick coatings of refractory metals may be electrodeposited from their solutions in molten salts.

  3. Reduction of selenite to elemental selenium nanoparticles by activated sludge.

    Science.gov (United States)

    Jain, Rohan; Matassa, Silvio; Singh, Satyendra; van Hullebusch, Eric D; Esposito, Giovanni; Lens, Piet N L

    2016-01-01

    Total selenium removal by the activated sludge process, where selenite is reduced to colloidal elemental selenium nanoparticles (BioSeNPs) that remain entrapped in the activated sludge flocs, was studied. Total selenium removal efficiencies with glucose as electron donor (2.0 g chemical oxygen demand (COD) L(-1)) at neutral pH and 30 °C gave 2.9 and 6.8 times higher removal efficiencies as compared to the electron donors lactate and acetate, respectively. Total selenium removal efficiencies of 79 (±3) and 86 (±1) % were achieved in shake flasks and fed batch reactors, respectively, at dissolved oxygen (DO) concentrations above 4.0 mg L(-1) and 30 °C when fed with 172 mg L(-1) (1 mM) Na2SeO3 and 2.0 g L(-1) COD of glucose. Continuously operated reactors operating at neutral pH, 30 °C and a DO >3 mg L(-1) removed 33.98 and 36.65 mg of total selenium per gram of total suspended solids (TSS) at TSS concentrations of 1.3 and 3.0 g L(-1), respectively. However, selenite toxicity to the activated sludge led to failure of a continuously operating activated sludge reactor at the applied loading rates. This suggests that a higher hydraulic retention time (HRT) or different reactor configurations need to be applied for selenium-removing activated sludge processes. Graphical Abstract Scheme representing the possible mechanisms of selenite reduction at high and low DO levels in the activated sludge process.

  4. Foire aux questions concernant la Bourse du CRDI aux chercheurs ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Suis-je admissible à la bourse du CRDI aux chercheurs candidats au doctorat si je suis inscrit à un programme d'études de doctorat, mais que je n'ai pas encore commencé mes cours ? 6. Je suis citoyen d'un pays en développement. Suis-je admissible à la bourse du CRDI aux chercheurs candidats au doctorat ? 7.

  5. Effect of selenite on the physiological and morphological properties of the blue-green alga Phormidium luridum var. Olivacea

    Energy Technology Data Exchange (ETDEWEB)

    Sielicki, M.; Burnham, J.C.

    1973-07-05

    Phormidium luridum cultures were treated with sodium selenite in concentrations ranging from 10/sup -6/ M to 10/sup -2/ M. In contrast to the increasing culture turbidity of control and 10/sup -6/ M selenite cultures, the turbidity of the other selenite cultures declined in proportion to time and selenite concentration. Chlorophyll extraction revealed similar results. Photosynthetic activity was inhibited within 6 hr in all cultures except control and 10/sup -6/ M selenite showed a gradual loss of the bright green color and turned semitransparent. Cell-associated granules of reduced selenium were observed at higher selenite concentrations. Other structural changes observed were the presence of intracellular and intercellular spaces, spheroplast formation, and gradual cell lysis. Protein analyses of total cell samples and supernatant fractions confirmed cellular breakdown of selenite-treated algal cells.

  6. The Comparative Studies of Binding Activity of Curcumin and Didemethylated Curcumin with Selenite: Hydrogen Bonding vs Acid-Base Interactions.

    Science.gov (United States)

    Liao, Jiahn-Haur; Wu, Tzu-Hua; Chen, Ming-Yi; Chen, Wei-Ting; Lu, Shou-Yun; Wang, Yi-Hsuan; Wang, Shao-Pin; Hsu, Yen-Min; Huang, Yi-Shiang; Huang, Zih-You; Lin, Yu-Ching; Chang, Ching-Ming; Huang, Fu-Yung; Wu, Shih-Hsiung

    2015-12-04

    In this report, the in vitro relative capabilities of curcumin (CCM) and didemethylated curcumin (DCCM) in preventing the selenite-induced crystallin aggregation were investigated by turbidity tests and isothermal titration calorimetry (ITC). DCCM showed better activity than CCM. The conformers of CCM/SeO3(2-) and DCCM/SeO3(2-) complexes were optimized by molecular orbital calculations. Results reveal that the selenite anion surrounded by CCM through the H-bonding between CCM and selenite, which is also observed via IR and NMR studied. For DCCM, the primary driving force is the formation of an acid-base adduct with selenite showing that the phenolic OH group of DCCM was responsible for forming major conformer of DCCM. The formation mechanisms of selenite complexes with CCM or DCCM explain why DCCM has greater activity than CCM in extenuating the toxicity of selenite as to prevent selenite-induced lens protein aggregation.

  7. The Comparative Studies of Binding Activity of Curcumin and Didemethylated Curcumin with Selenite: Hydrogen Bonding vs Acid-Base Interactions

    Science.gov (United States)

    Liao, Jiahn-Haur; Wu, Tzu-Hua; Chen, Ming-Yi; Chen, Wei-Ting; Lu, Shou-Yun; Wang, Yi-Hsuan; Wang, Shao-Pin; Hsu, Yen-Min; Huang, Yi-Shiang; Huang, Zih-You; Lin, Yu-Ching; Chang, Ching-Ming; Huang, Fu-Yung; Wu, Shih-Hsiung

    2015-12-01

    In this report, the in vitro relative capabilities of curcumin (CCM) and didemethylated curcumin (DCCM) in preventing the selenite-induced crystallin aggregation were investigated by turbidity tests and isothermal titration calorimetry (ITC). DCCM showed better activity than CCM. The conformers of CCM/SeO32- and DCCM/SeO32- complexes were optimized by molecular orbital calculations. Results reveal that the selenite anion surrounded by CCM through the H-bonding between CCM and selenite, which is also observed via IR and NMR studied. For DCCM, the primary driving force is the formation of an acid-base adduct with selenite showing that the phenolic OH group of DCCM was responsible for forming major conformer of DCCM. The formation mechanisms of selenite complexes with CCM or DCCM explain why DCCM has greater activity than CCM in extenuating the toxicity of selenite as to prevent selenite-induced lens protein aggregation.

  8. Selenite transport in unsaturated tuff from Yucca Mountain

    International Nuclear Information System (INIS)

    Conca, J.L.; Triay, I.R.

    1994-01-01

    Direct measurements of unsaturated selenite retardation coefficients and unsaturated hydraulic conductivity were obtained on two tuff samples from Yucca Mountain using the UFA trademark technology. The retardation factor for the selenite species was only 2.5 in both Yucca Mountain vitric member at 62.6% saturation and zeolitized nonwelded tuff from G-tunnel at 52.8% saturation with respect to J-13 well water from the Nevada Test Site contaminated with selenium at 1.31 mg/l (ppm). In batch tests on the same material using 1.2 mg/l (ppm), the average K d was determined to be 13, giving retardation factors higher than the UFA column breakthrough tests by an order of magnitude. The difference could result from preferential flow paths in the UFA column as might occur in the field or differences in residence times between the two types of test. The unsaturated hydraulic conductivities during the experiments were 2.49 x 10 -8 cm/s for the Yucca Mountain vitric member and 1.16 x 10 -8 cm/s for the zeolitized nonwelded tuff

  9. Transcriptional Response of Selenopolypeptide Genes and Selenocysteine Biosynthesis Machinery Genes in Escherichia coli during Selenite Reduction

    Directory of Open Access Journals (Sweden)

    Antonia Y. Tetteh

    2014-01-01

    Full Text Available Bacteria can reduce toxic selenite into less toxic, elemental selenium (Se0, but the mechanism on how bacterial cells reduce selenite at molecular level is still not clear. We used Escherichia coli strain K12, a common bacterial strain, as a model to study its growth response to sodium selenite (Na2SeO3 treatment and then used quantitative real-time PCR (qRT-PCR to quantify transcript levels of three E. coli selenopolypeptide genes and a set of machinery genes for selenocysteine (SeCys biosynthesis and incorporation into polypeptides, whose involvements in the selenite reduction are largely unknown. We determined that 5 mM Na2SeO3 treatment inhibited growth by ∼50% while 0.001 to 0.01 mM treatments stimulated cell growth by ∼30%. Under 50% inhibitory or 30% stimulatory Na2SeO3 concentration, selenopolypeptide genes (fdnG, fdoG, and fdhF whose products require SeCys but not SeCys biosynthesis machinery genes were found to be induced ≥2-fold. In addition, one sulfur (S metabolic gene iscS and two previously reported selenite-responsive genes sodA and gutS were also induced ≥2-fold under 50% inhibitory concentration. Our findings provide insight about the detoxification of selenite in E. coli via induction of these genes involved in the selenite reduction process.

  10. Selenium homeostasis and induction of thioredoxin reductase during long term selenite supplementation in the rat

    DEFF Research Database (Denmark)

    Erkhembayar, Suvd; Mollbrink, Annelie; Eriksson, Malin

    2011-01-01

    selenium levels was also seen, and the induction of TrxR1 mRNA was seen only during the first three days of treatment, when the levels of selenium in the liver were increasing. Sodium selenite at 1 and 5μg/mL did not affect body weight or relative liver mass. We concluded that long-term treatment...... with selenite did not cause accumulation of selenium and that the activity of TrxR1 in the liver rose with the selenium levels. We therefore suggest that sodium selenite at doses up to 5μg/mL could be used for long-term tumour prevention....

  11. Evaluation of sorption capacity of modified wood biomass for arsenic five-valent oxyanions

    International Nuclear Information System (INIS)

    Littera, P.; Antoska, R.; Cernansky, S.; Sevc, J.; Kolencik, M.; Budzakova, M.

    2009-01-01

    In the present work is assessed bio-sorption of arsenic oxyanions, which represent one of two most common special arsenic occurring in contaminated waters. A wood biomass was used as sorbent, which was modified by amorphous oxohydroxides of iron to increase sorption capacity, to whom arsenic has high affinity. The work estimated sorption capacity of wood biomass adjusted by oxohydroxides of iron. The Langmuir model as well as the Freundlich model were suitable for evaluation of experimental results. Maximal sorption capacity of investigated sorbent was 9.259 mg/g, what is comparable with values published by other authors.

  12. Recycling of spent adsorbents for oxyanions and heavy metal ions in the production of ceramics.

    Science.gov (United States)

    Verbinnen, Bram; Block, Chantal; Van Caneghem, Jo; Vandecasteele, Carlo

    2015-11-01

    Spent adsorbents for oxyanion forming elements and heavy metals are classified as hazardous materials and they are typically treated by stabilization/solidification before landfilling. The use of lime or cement for stabilization/solidification entails a high environmental impact and landfilling costs are high. This paper shows that mixing spent adsorbents in the raw material for the production of ceramic materials is a valuable alternative to stabilize oxyanion forming elements and heavy metals. The produced ceramics can be used as construction material, avoiding the high economic and environmental impact of stabilization/solidification followed by landfilling. To study the stabilization of oxyanion forming elements and heavy metals during the production process, two series of experiments were performed. In the first series of experiments, the main pollutant, Mo was adsorbed onto iron-based adsorbents, which were then mixed with industrial sludge (3 w/w%) and heated at 1100°C for 30 min. Mo was chosen, as this element is easily adsorbed onto iron-based adsorbents and it is the element that is the most difficult to stabilize (i.e. the highest temperatures need to be reached before the concentrations in the leachate are reduced). Leaching concentration from the 97/3 sludge/adsorbent mixture before heating ranged between 85 and 154 mg/kg; after the heating process they were reduced to 0.42-1.48 mg/kg. Mo was actually stabilized, as the total Mo concentration after addition was not affected by the heat treatment. In the second series of experiments, the sludge was spiked with other heavy metals and oxyanion forming elements (Cr, Ni, Cu, Zn, As, Cd and Pb) in concentrations 5 times higher than the initial concentrations; after heat treatment the leachate concentrations were below the regulatory limit values. The incorporation of spent adsorbents in ceramic materials is a valuable and sustainable alternative to the existing treatment methods, saving raw materials in the

  13. Foire aux questions sur la bourse du CRDI aux chercheurs ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    Est-ce que je peux utiliser une partie de la bourse pour payer son billet d'avion ? 1) Je suis étudiant au doctorat et la bourse du CRDI aux chercheurs candidats au doctorat m'intéresse. Pourriez-vous me faire parvenir de la documentation au sujet de cette bourse ? Tous les renseignements concernant la bourse du CRDI ...

  14. Study of the selenite reduction in Rhodobacter sphaeroides f. sp. denitrificans

    International Nuclear Information System (INIS)

    Bernier-Pierru, B.

    2006-05-01

    Selenium is an essential element for all living organisms at the low level; however it becomes toxic and mutagenic at higher concentrations. The predominant forms of selenium in natural environments are selenate and selenite which are toxic. Bacteria can use several mechanisms of detoxification such as methylation in volatile compounds or reduction in elemental selenium. In this way, our model, Rhodobacter sphaeroides f. sp. denitrificans, is able to reduce selenite into selenium. We have combined biochemical and molecular approaches to better characterize the mechanism and protagonists of this reduction. After studying the physiological response of the bacterium in the presence of selenite, we screened a transposon library in order to isolate mutants with a weakened reduction ability. Two of these selected mutants are affected in genes involved in the molybdenum cofactor synthesis, moaA and mogA. Several reductases, the molybdo enzymes, required this cofactor. Furthermore the addition of tungsten, a competitor for the molybdenum, in the culture medium, dramatically reduces the rate of selenite reduction. These results strongly suggest that a molybdo enzyme is involved in one of the selenite reduction pathways. The potential role of different proteins has been investigated, especially for the nitrate reductase, the DMSO reductase and the biotin sulfoxide reductase. We have also selected a mutant affected in the smoM gene which encodes a peri-plasmic component of a TRAP transporter. The phenotype of this mutant suggests the involvement of this transporter in the selenite import. (author)

  15. Selenite exacerbates hepatic insulin resistance in mouse model of type 2 diabetes through oxidative stress-mediated JNK pathway

    International Nuclear Information System (INIS)

    Zhou, Jun; Xu, Gang; Bai, Zhaoshuai; Li, Kaicheng; Yan, Junyan; Li, Fen; Ma, Shuai; Xu, Huibi; Huang, Kaixun

    2015-01-01

    Recent evidence suggests a potential pro-diabetic effect of selenite treatment in type 2 diabetics; however, the underlying mechanisms remain elusive. Here we investigated the effects and the underlying mechanisms of selenite treatment in a nongenetic mouse model of type 2 diabetes. High-fat diet (HFD)/streptozotocin (STZ)-induced diabetic mice were orally gavaged with selenite at 0.5 or 2.0 mg/kg body weight/day or vehicle for 4 weeks. High-dose selenite treatment significantly elevated fasting plasma insulin levels and insulin resistance index, in parallel with impaired glucose tolerance, insulin tolerance and pyruvate tolerance. High-dose selenite treatment also attenuated hepatic IRS1/Akt/FoxO1 signaling and pyruvate kinase gene expressions, but elevated the gene expressions of phosphoenolpyruvate carboxyl kinase (PEPCK), glucose 6-phosphatase (G6Pase), peroxisomal proliferator-activated receptor-γ coactivator 1α (PGC-1α) and selenoprotein P (SelP) in the liver. Furthermore, high-dose selenite treatment caused significant increases in MDA contents, protein carbonyl contents, and a decrease in GSH/GSSG ratio in the liver, concurrent with enhanced ASK1/MKK4/JNK signaling. Taken together, these findings suggest that high-dose selenite treatment exacerbates hepatic insulin resistance in mouse model of type 2 diabetes, at least in part through oxidative stress-mediated JNK pathway, providing new mechanistic insights into the pro-diabetic effect of selenite in type 2 diabetes. - Highlights: • Selenite exacerbates hepatic insulin resistance in HFD/STZ-induced diabetic mice. • Selenite elevates hepatic gluconeogenesis and reduces glycolysis in diabetic mice. • Selenite exacerbates hepatic oxidative stress and triggers JNK signaling pathway. • Selenite elevates hepatic selenoprotein P expression in diabetic mice.

  16. Simultaneous leaching of arsenite, arsenate, selenite and selenate, and their migration in tunnel-excavated sedimentary rocks: I. Column experiments under intermittent and unsaturated flow.

    Science.gov (United States)

    Tabelin, Carlito Baltazar; Sasaki, Ryosuke; Igarashi, Toshifumi; Park, Ilhwan; Tamoto, Shuichi; Arima, Takahiko; Ito, Mayumi; Hiroyoshi, Naoki

    2017-11-01

    Rocks excavated in tunnel construction projects for roads and railways throughout Japan often leached out hazardous trace elements like arsenic (As) and selenium (Se) upon their exposure to the environment. In nature, the various oxyanionic species of As and Se not only coexist but also exhibit contrasting adsorption-desorption behaviors, so speciation is a crucial factor in their migration through natural geologic media. In this study, the leaching and transport of arsenite (As III ), arsenate (As V ), selenite (Se IV ) and selenate (Se VI ) in four tunnel-excavated rocks from the Cretaceous-Paleocene Yezo forearc basin were investigated using laboratory column experiments supplemented by batch leaching experiments. The single- and consecutive-batch leaching results revealed that As III , As V , Se IV and Se VI were released simultaneously, which could be attributed to the rapid dissolution of trace evaporite salts found in the rocks. Arsenic in the leachates was also predominated by As V while Se IV and Se VI concentrations were nearly equal, which are both consistent with predictions of equilibrium Eh-pH diagrams. Under intermittent and unsaturated flow, however, periods when As III and Se VI predominated in the effluents were observed. Spatial distributions of As and Se species with depth at the end of the column experiments suggest that migrations of As III , As V and Se IV were delayed, the extent of which depended on the rock. These results indicate that migration and speciation of As and Se in the rocks are controlled by preferential adsorption-desorption reactions, the effects of which were most probably magnified by changes in the pH and concentrations of coexisting ions due to intermittent and unsaturated flow. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. High Pressure Reduction of Selenite by Shewanella oneidensis MR-1

    Science.gov (United States)

    Picard, A.; Daniel, I.; Testemale, D.; Letard, I.; Bleuet, P.; Cardon, H.; Oger, P.

    2007-12-01

    High-pressure biotopes comprise cold deep-sea environments, hydrothermal vents, and deep subsurface or deep-sea sediments. The latter are less studied, due to the technical difficulties to sample at great depths without contamination. Nevertheless, microbial sulfate reduction and methanogenesis have been found to be spatially distributed in deep deep-sea sediments (1), and sulfate reduction has been shown to be actually more efficient under high hydrostatic pressure (HHP) in some sediments (2). Sulfate-reducing bacteria obtained from the Japan Sea are characterized by an increased sulfide production under pressure (3,4). Unfortunately, investigations of microbial metabolic activity as a function of pressure are extremely scarce due to the experimental difficulty of such measurements at high hydrostatic pressure. We were able to measure the reduction of selenite Se(IV) by Shewanella oneidensis MR-1 as a function of pressure, to 150 MPa using two different high-pressure reactors that allow in situ X-ray spectroscopy measurements on a synchrotron source. A first series of measurements was carried out in a low-pressure Diamond Anvil Cell (DAC) of our own design (5) at ID22 beamline at ESRF (European Synchrotron Radiation Facility); a second one was performed in an autoclave (6) at the BM30B beamline at ESRF. Selenite reduction by strain MR-17 was monitored from ambient pressure to 150 MPa over 25 hours at 30 deg C by XANES spectroscopy (X-ray Analysis of Near Edge Structure). Spectra were recorded hourly in order to quantify the evolution of the oxidation state of selenium with time. Stationary-phase bacteria were inoculated at a high concentration into fresh growth medium containing 5 or 10 M of sodium selenite and 20 mM sodium lactate. Kinetic parameters of the Se (IV) reduction by Shewanella oneidensis strain MR-1 could be extracted from the data, as a function of pressure. They show 1) that the rate constant k of the reaction is decreased by a half at high pressure

  18. Adsorption of Oxy-Anions in the Teaching Laboratory: An Experiment to Study a Fundamental Environmental Engineering Problem

    Science.gov (United States)

    D'Arcy, Mitch; Bullough, Florence; Moffat, Chris; Borgomeo, Edoardo; Teh, Micheal; Vilar, Ramon; Weiss, Dominik J.

    2014-01-01

    Synthesizing and testing bicomposite adsorbents for the removal of environmentally problematic oxy-anions is high on the agenda of research-led universities. Here we present a laboratory module successfully developed at Imperial College London that introduces the advanced undergraduate student in engineering (chemical, civil, earth) and science…

  19. Selenite-induced hormonal and signalling mechanisms during root growth of Arabidopsis thaliana L.

    Science.gov (United States)

    Lehotai, Nóra; Kolbert, Zsuzsanna; Peto, Andrea; Feigl, Gábor; Ördög, Attila; Kumar, Devanand; Tari, Irma; Erdei, László

    2012-09-01

    Selenium excess can cause toxicity symptoms, e.g. root growth inhibition in non-hyperaccumulator plants such as Arabidopsis. Selenite-induced hormonal and signalling mechanisms in the course of development are poorly understood; therefore this study set out to investigate the possible hormonal and signalling processes using transgenic and mutant Arabidopsis plants. Significant alterations were observed in the root architecture of the selenite-treated plants, due to the loss of cell viability in the root apex. During mild selenite excess, the plants showed symptoms of the morphogenic response: primary root (PR) shortening and increased initiation of laterals, ensuring better nutrient and water uptake and stress acclimation. As well as lower meristem cell activity, the second reason for the Se-induced growth hindrance is the hormonal imbalance, since the in situ expression of the auxin-responsive DR5::GUS, and consequently the auxin levels, significantly decreased, while that of the cytokinin-inducible ARR5::GUS and the ethylene biosynthetic ACS8::GUS increased. It is assumed that auxin and ethylene might positively regulate selenium tolerance, since reduced levels of them resulted in sensitivity. Moreover, high cytokinin levels caused notable selenite tolerance. During early seedling development, nitric oxide (NO) contents decreased but hydrogen peroxide levels increased reflecting the antagonism between the two signal molecules during Se excess. High levels of NO in gsnor1-3, lead to selenite tolerance, while low NO production in nia1nia2 resulted in selenite sensitivity. Consequently, NO derived from the root nitrate reductase activity is responsible for the large-scale selenite tolerance in Arabidopsis.

  20. Selenite-induced nitro-oxidative stress processes in Arabidopsis thaliana and Brassica juncea.

    Science.gov (United States)

    Molnár, Árpád; Kolbert, Zsuzsanna; Kéri, Krisztina; Feigl, Gábor; Ördög, Attila; Szőllősi, Réka; Erdei, László

    2018-02-01

    Extremes of selenium (Se) exert toxic effects on plants' physiological processes; although plant species tolerate Se differently. This study focuses on the effect of Se (0, 20, 50 or 100μM sodium selenite) on secondary nitro-oxidative stress processes mainly using in situ microscopic methods in non-accumulator Arabidopsis thaliana and secondary Se accumulator Brassica juncea. Relative Se tolerance or sensitivity of the species was evaluated based on growth parameters (fresh and dry weight, root growth) and cell viability. Besides, selenite-triggered cell wall modifications (pectin, callose) and stomatal regulations were determined for the first time. In case of Arabidopsis, relative selenite sensitivity was accompanied by decreased stomatal density and induced stomatal opening, callose accumulation, pronounced oxidative stress and moderate nitrosative modifications. In contrast, the selenite-treated, relatively tolerant Brassica juncea showed larger number of more opened stomata, pectin accumulation, moderate oxidative and intense nitrosative stress. These suggest that selenite tolerance or sensitivity is rather associated with oxidative processes than secondary nitrosative modifications in higher plants. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Protective effects of sodium selenite on lead nitrate-induced hepatotoxicity in diabetic and non-diabetic rats.

    Science.gov (United States)

    Kalender, Suna; Apaydin, Fatma Gökçe; Baş, Hatice; Kalender, Yusuf

    2015-09-01

    In the present study, the effect of sodium selenite on lead induced toxicity was studied in Wistar rats. Sodium selenite and lead nitrate were administered orally for 28 days to streptozotocin induced diabetic and non-diabetic rats. Eight groups of rats were used in the study: control, sodium selenite, lead nitrate, lead nitrate+sodium selenite, streptozotocin-induced diabetic-control, diabetic-sodium selenite, diabetic-lead nitrate, diabetic-lead nitrate+sodium selenite groups. Serum biochemical parameters, lipid peroxidation, antioxidant enzymes and histopathological changes in liver tissues were investigated in all groups. There were statistically significant changes in liver function tests, antioxidant enzyme activities and lipid peroxidation levels in lead nitrate and sodium selenite+lead nitrate treated groups, also in diabetic and non-diabetic groups. Furthermore, histopathological alterations were demonstrated in same groups. In the present study we found that sodium selenite treatment did not show completely protective effect on diabetes mellitus caused damages, but diabetic rats are more susceptible to lead toxicity than non-diabetic rats. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Uptake and Distribution of Added Selenite and Selenate by Barley and Red Clover as Influenced by Sulphur

    DEFF Research Database (Denmark)

    Nielsen, Gunnar Gissel

    1973-01-01

    The uptake of added Se from selenite and selenate by barley and red clover was investigated in a pot experiment. Much more of selenate than of selenite was taken up but the Se concentrations in the plants declined more with time when selenate was the source. Increasing sulphate addition to the soil...

  3. Effect of alkali metals nature on composition and properties of double gallium selenites

    International Nuclear Information System (INIS)

    Tananaev, I.V.; Volodina, A.N.; Bol'shakova, N.K.; Petrov, K.I.

    1975-01-01

    Chemical, X-ray and optical analysis as well as infra-red spectroscopy and thermography methods were used to show that the hydrothermal crystallization of Ga 2 (SeO 3 ).6H 2 O in solutions of LiH 3 (SeO 3 ) 2 and NaH 3 (SeO 3 ) 2 leads to the formation of a macrocrystalline lower crystal hydrate of neutral gallium selenite whose composition is Ga 2 (SeO 3 ).2H 2 O. Under the same conditions, acidic gallium selenite GaH(SeO 3 ) 2 .2H 2 O is formed in solutions of KH 3 (SeO 3 ) 2 ; binary gallium selenites of compostion Msub(x)sup(I)H-sub(x)Ga(SeO 3 ) 2 .H 2 O are formed in solutions of CsH 3 (SeO 3 ) 2 and RbH 3 (SeO 3 ) 2 . (author)

  4. Sodium Selenite Prevents Paraquat-Induced Neurotoxicity in Zebrafish.

    Science.gov (United States)

    Müller, Talise E; Nunes, Mauro E; Menezes, Charlene C; Marins, Aline T; Leitemperger, Jossiele; Gressler, Ana Carolina Lopes; Carvalho, Fabiano B; de Freitas, Catiuscia Molz; Quadros, Vanessa A; Fachinetto, Roselei; Rosemberg, Denis B; Loro, Vania L

    2018-03-01

    Considering the antioxidant properties of sodium selenite (Na 2 SeO 3 ) and the involvement of oxidative stress events in paraquat-induced neurotoxicity, this study investigated the protective effect of dietary Na 2 SeO 3 on biochemical and behavioral parameters of zebrafish exposed to paraquat (PQ). Fish were pretreated with a Na 2 SeO 3 diet for 21 days and then PQ (20 mg/kg) was administered intraperitoneally with six injections for 16 days. In the novel tank test, the Na 2 SeO 3 diet prevented the locomotor impairments, as well as the increase in the time spent in the top area of the tank, and the exacerbation of freezing episodes. In the preference for conspecifics and in the mirror-induced aggression (MIA) tasks, Na 2 SeO 3 prevented the increase in the latency to enter the area closer to conspecifics and the agonistic behavior of PQ-treated animals, respectively. Na 2 SeO 3 prevented the increase of carbonylated protein (CP), reactive oxygen species (ROS), and nitrite/nitrate (NOx) levels, as well as the decrease in non-protein thiols (NPSH) levels. Regarding the antioxidant enzymatic defenses, Na 2 SeO 3 prevented the increase in catalase (CAT) and glutathione peroxidase (GPx) activities caused by PQ. Altogether, dietary Na 2 SeO 3 improves behavioral and biochemical function impaired by PQ treatment in zebrafish, by modulating not only redox parameters, but also anxiety- and aggressive-like phenotypes in zebrafish.

  5. Polarographic behaviour and determination of selenite and tellurite in simple solutions or in a binary mixture

    International Nuclear Information System (INIS)

    Hassan, A.

    1991-01-01

    The polarographic behaviour of simple solutions of selenite and tellurite in 1 M ammonium salts of formate, acetate, tartrate, oxalate, and benzoate solutions in absence and in presence of Triton X-100 as a maximum suppressor and a temperature of 25 O C has been investigated. Schemes for the mechanism of reductions occuring at the DME have been deduced. A method for analytical determination of selenite and tellurite in simple solutions as well as in a binary mixture in the presence of 4-14 . 10 -3 % Triton X-100 is reported. (author)

  6. The thermodynamics of arsenates, selenites, and sulfates in the oxidation zone of sulfide ores. XI. Solubility of synthetic chalcomenite analog and zinc selenite at 25°C

    Science.gov (United States)

    Charykova, M. V.; Krivovichev, V. G.; Ivanova, N. M.; Semenova, V. V.

    2015-12-01

    The aim of this study is the synthesis of CuSeO3·2H2O (chalcomenite analog), ZnSeO3·2H2O, and ZnSeO3·H2O and the investigation of their solubility in water. CuSeO3·2H2O has been synthesized from solutions of Cu nitrate and Na selenite, while Zn selenites were synthesized from solutions of Zn nitrate and Na selenite. The samples obtained have been examined with X-ray diffraction and infrared and Raman spectroscopy. The solubility has been determined using the isothermal saturation method in ampoules at 25°C. The solubility has been calculated using the Geochemist's Workbench (GMB 9.0) software package. Solubility products have been calculated for CuSeO3·2H2O (10-10.63), ZnSeO3·2H2O (10-8.35), and ZnSeO3·H2O (10-7.96). The database used comprises thermodynamic characteristics of 46 elements, 47 base particles, 48 redox pairs, 551 particles in solution, and 624 solid phases. The Eh-pH diagrams of the Zn-Se-H2O and Cu-Se-H2O systems were plotted for the average contents of these elements in underground water in oxidation zones of sulfide deposits.

  7. Kinetics of Cation and Oxyanion Adsorption and Desorption on Ferrihydrite: Roles of Ferrihydrite Binding Sites and a Unified Model

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Lei [School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People’s Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry; Shi, Zhenqing [School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People’s Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry; Lu, Yang [School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People’s Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry; Dohnalkova, Alice C. [Environmental; Lin, Zhang [School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People’s Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry; Dang, Zhi [School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People’s Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry

    2017-08-29

    Understanding the kinetics of toxic ion reactions with ferrihydrite is crucial for predicting the dynamic behavior of contaminants in soil environments. In this study, the kinetics of As(V), Cr(VI), Cu, and Pb adsorption and desorption on ferrihydrite were investigated with a combination of laboratory macroscopic experiments, microscopic investigation and mechanistic modeling. The rates of As(V), Cr(VI), Cu, and Pb adsorption and desorption on ferrihydrite, as systematically studied using a stirred-flow method, was highly dependent on the reaction pH and metal concentrations and varied significantly among four metals. Spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) showed, at sub-nano scales, all four metals were distributed within the ferrihydrite particle aggregates homogeneously after adsorption reactions, with no evidence of surface diffusion-controlled processes. Based on experimental results, we developed a unifying kinetics model for both cation and oxyanion adsorption/desorption on ferrihydrite based on the mechanistic-based equilibrium model CD-MUSIC. Overall, the model described the kinetic results well, and we quantitatively demonstrated how the equilibrium properties of the cation and oxyanion binding to various ferrihydrite sites affected the adsorption and desorption rates. Our results provided a unifying quantitative modeling method for the kinetics of both cation and oxyanion adsorption/desorption on iron minerals.

  8. Kinetics of Cation and Oxyanion Adsorption and Desorption on Ferrihydrite: Roles of Ferrihydrite Binding Sites and a Unified Model.

    Science.gov (United States)

    Tian, Lei; Shi, Zhenqing; Lu, Yang; Dohnalkova, Alice C; Lin, Zhang; Dang, Zhi

    2017-09-19

    Quantitative understanding the kinetics of toxic ion reactions with various heterogeneous ferrihydrite binding sites is crucial for accurately predicting the dynamic behavior of contaminants in environment. In this study, kinetics of As(V), Cr(VI), Cu(II), and Pb(II) adsorption and desorption on ferrihydrite was studied using a stirred-flow method, which showed that metal adsorption/desorption kinetics was highly dependent on the reaction conditions and varied significantly among four metals. High resolution scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy showed that all four metals were distributed within the ferrihydrite aggregates homogeneously after adsorption reactions. Based on the equilibrium model CD-MUSIC, we developed a novel unified kinetics model applicable for both cation and oxyanion adsorption and desorption on ferrihydrite, which is able to account for the heterogeneity of ferrihydrite binding sites, different binding properties of cations and oxyanions, and variations of solution chemistry. The model described the kinetic results well. We quantitatively elucidated how the equilibrium properties of the cation and oxyanion binding to various ferrihydrite sites and the formation of various surface complexes controlled the adsorption and desorption kinetics at different reaction conditions and time scales. Our study provided a unified modeling method for the kinetics of ion adsorption/desorption on ferrihydrite.

  9. Differential Acute Effects of Selenomethionine and Sodium Selenite on the Severity of Colitis

    Directory of Open Access Journals (Sweden)

    Franziska Hiller

    2015-04-01

    Full Text Available The European population is only suboptimally supplied with the essential trace element selenium. Such a selenium status is supposed to worsen colitis while colitis-suppressive effects were observed with adequate or supplemented amounts of both organic selenomethionine (SeMet and inorganic sodium selenite. In order to better understand the effect of these selenocompounds on colitis development we examined colonic phenotypes of mice fed supplemented diets before the onset of colitis or during the acute phase. Colitis was induced by treating mice with 1% dextran sulfate sodium (DSS for seven days. The selenium-enriched diets were either provided directly after weaning (long-term or were given to mice with a suboptimal selenium status after DSS withdrawal (short-term. While long-term selenium supplementation had no effect on colitis development, short-term selenite supplementation, however, resulted in a more severe colitis. Colonic selenoprotein expression was maximized in all selenium-supplemented groups independent of the selenocompound or intervention time. This indicates that the short-term selenite effect appears to be independent from colonic selenoprotein expression. In conclusion, a selenite supplementation during acute colitis has no health benefits but may even aggravate the course of disease.

  10. Reduction of selenite by Azospirillum brasilense with the formation of selenium nanoparticles.

    Science.gov (United States)

    Tugarova, Anna V; Vetchinkina, Elena P; Loshchinina, Ekaterina A; Burov, Andrei M; Nikitina, Valentina E; Kamnev, Alexander A

    2014-10-01

    The ability to reduce selenite (SeO(3)(2-)) ions with the formation of selenium nanoparticles was demonstrated in Azospirillum brasilense for the first time. The influence of selenite ions on the growth of A. brasilense Sp7 and Sp245, two widely studied wild-type strains, was investigated. Growth of cultures on both liquid and solid (2 % agar) media in the presence of SeO(3)(2-) was found to be accompanied by the appearance of the typical red colouration. By means of transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS) and X-ray fluorescence analysis (XFA), intracellular accumulation of elementary selenium in the form of nanoparticles (50 to 400 nm in diameter) was demonstrated for both strains. The proposed mechanism of selenite-to-selenium (0) reduction could involve SeO(3)(2-) in the denitrification process, which has been well studied in azospirilla, rather than a selenite detoxification strategy. The results obtained point to the possibility of using Azospirillum strains as endophytic or rhizospheric bacteria to assist phytoremediation of, and cereal cultivation on, selenium-contaminated soils. The ability of A. brasilense to synthesise selenium nanoparticles may be of interest to nanobiotechnology for "green synthesis" of bioavailable amorphous red selenium nanostructures.

  11. The intensity of tyrosine nitration is associated with selenite and selenate toxicity in Brassica juncea L.

    Science.gov (United States)

    Molnár, Árpád; Feigl, Gábor; Trifán, Vanda; Ördög, Attila; Szőllősi, Réka; Erdei, László; Kolbert, Zsuzsanna

    2018-01-01

    Selenium phytotoxicity involves processes like reactive nitrogen species overproduction and nitrosative protein modifications. This study evaluates the toxicity of two selenium forms (selenite and selenate at 0µM, 20µM, 50µM and 100µM concentrations) and its correlation with protein tyrosine nitration in the organs of hydroponically grown Indian mustard (Brassica juncea L.). Selenate treatment resulted in large selenium accumulation in both Brassica organs, while selenite showed slight root-to-shoot translocation resulting in a much lower selenium accumulation in the shoot. Shoot and root growth inhibition and cell viability loss revealed that Brassica tolerates selenate better than selenite. Results also show that relative high amounts of selenium are able to accumulate in Brassica leaves without obvious visible symptoms such as chlorosis or necrosis. The more severe phytotoxicity of selenite was accompanied by more intense protein tyrosine nitration as well as alterations in nitration pattern suggesting a correlation between the degree of Se forms-induced toxicities and nitroproteome size, composition in Brassica organs. These results imply the possibility of considering protein tyrosine nitration as novel biomarker of selenium phytotoxicity, which could help the evaluation of asymptomatic selenium stress of plants. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Deletion of thioredoxin reductase and effects of selenite and selenate toxicity in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Christopher J Boehler

    Full Text Available Thioredoxin reductase-1 (TRXR-1 is the sole selenoprotein in C. elegans, and selenite is a substrate for thioredoxin reductase, so TRXR-1 may play a role in metabolism of selenium (Se to toxic forms. To study the role of TRXR in Se toxicity, we cultured C. elegans with deletions of trxr-1, trxr-2, and both in axenic media with increasing concentrations of inorganic Se. Wild-type C. elegans cultured for 12 days in Se-deficient axenic media grow and reproduce equivalent to Se-supplemented media. Supplementation with 0-2 mM Se as selenite results in inverse, sigmoidal response curves with an LC50 of 0.20 mM Se, due to impaired growth rather than reproduction. Deletion of trxr-1, trxr-2 or both does not modulate growth or Se toxicity in C. elegans grown axenically, and (75Se labeling showed that TRXR-1 arises from the trxr-1 gene and not from bacterial genes. Se response curves for selenide (LC50 0.23 mM Se were identical to selenite, but selenate was 1/4(th as toxic (LC50 0.95 mM Se as selenite and not modulated by TRXR deletion. These nutritional and genetic studies in axenic media show that Se and TRXR are not essential for C. elegans, and that TRXR alone is not essential for metabolism of inorganic Se to toxic species.

  13. Experimental Study and modelling of the Sorption of Selenite and Europium Onto Smectite and Illite Clays

    Energy Technology Data Exchange (ETDEWEB)

    Missana, T.; Alonso, U.; Garcia-Gutierrez, M.

    2009-10-12

    This study provides a large set of experimental selenite sorption data for pure smectite and illite. Similar sorption behavior existed in both clays: linear within a large range of the Se concentrations investigated and independent of ionic strength. Selenite sorption was also analysed in the illite/smectite system with the clays mixed in two different proportions. The objective of the study was to provide the simplest model possible to fit the experimental data, a model also capable of describing selenite sorption in binary illite/smectite clay systems. Selenite sorption data were modeled using both a one-and a two-site non-electrostatic model that took into account the formation of two complexes at the edge sites of the clay. The complexation constants obtained by fitting sorption data of the individual minerals were incorporated into a model to predict the adsorption of selenium in the illite/ smectite mixtures; the models predictions were consistent with the experimental adsorption data. (Author) 42 refs.

  14. Mechanisms regulating the reduction of selenite by aerobic gram (+) and (-) bacteria

    International Nuclear Information System (INIS)

    Garbisu, C.; Ishii, Takahisa; Yee, B.C.; Carlson, D.E.; Buchanan, B.B.; Leighton, T.; Smith, N.R.; Yee, A.

    1995-01-01

    Toxic species of selenium are pollutants found in agricultural and oil refinery wastestreams. Selenium contamination is particularly problematic in areas that have seleniferous subsurface geology, such as the central valley of California. The authors are developed a bacterial treatment system to mitigate selenium-contaminated wastestreams using Bacillus subtilis and Pseudomonas fluorescens, respectively, as model gram (+) and (-) soil bacteria. They have found that, during growth, both organisms reduce selenite, a major soluble toxic species, to red elemental selenium--an insoluble product generally regarded as nontoxic. In both cases, reduction depended on growth substrate and was effected by an inducible system that effectively removed selenite at concentrations typical of polluted sites--i.e., 50 to 300 microg/L. The bacteria studied differed in one respect: when grown in medium supplemented with nitrate or sulfate, the ability of P. fluorescens to remediate selenite was enhanced, whereas that of B. subtilis was unchanged. Current efforts are being directed toward understanding the biochemical mechanism(s) of detoxification and determining whether bacteria occurring in polluted environments such as soils and sludge systems are capable of selenite remediation

  15. Effect of sodium selenite on bone repair in tibiae of irradiated rats

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Anna Silvia Setti da [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR, (Brazil). Dept. of Physics; Ramos-Perez, Flavia Maria de Moraes; Boscolo, Frab Norberto; Almeida, Solange Maria [Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP (Brazil). Piracicaba Dental School. Dept. of Oral Diagnosis], e-mail: flaviamaria@fop.unicamp.br; Manzi, Flavio Ricardo [Pontifical Catholic University of Minas Gerais (PUC-MG), Belo Horizonte, MG (Brazil). Dept. of Stomatology; Chicareli, Mariliani [State Univ. of Maringa, PR (Brazil). Dept. of Oral Diagnosis

    2009-07-01

    This study evaluated the radioprotective effect of sodium selenite on the bone repair process in tibiae of female rats. For such purpose, 100 female Wistar rats (Rattus norvegicus, albinus) were randomly assigned to 4 groups (n=25), according to the treatment received: administration of distilled water (control); administration of sodium selenite; gamma radiation; and administration of sodium selenite plus gamma radiation. A bone defect was prepared on both tibiae of all animals. Three days after surgery, the gamma radiation and selenium/ gamma radiation groups received 8 Gy gamma rays on the lower limbs. Five animals per group were sacrificed 7, 14, 21, 28 days after surgery for evaluation of the repair process by bone volumetric density analysis. The 5 animals remaining in each group were sacrificed 45 days postoperatively for examination of the mature bone by scanning electron microscopy. Based on all analyzed parameters, the results of the present study suggest that sodium selenite exerted a radioprotective effect in the bone repair of tibia of irradiated rats. (author)

  16. Selenite reduction by mackinawite, magnetite and siderite: XAS characterization of nanosized redox products.

    Science.gov (United States)

    Scheinost, Andreas C; Charlet, Laurent

    2008-03-15

    Suboxic soils and sediments often contain the Fe(II)-bearing minerals mackinawite (FeS), siderite (FeCO3) or magnetite (FesO4), which should be able to reduce aqueous selenite, thereby forming solids of low solubility. While the reduction of selenate or selenite to Se(O) by green rust, pyrite and by Fe2+ sorbed to montmorillonite is a slow (weeks), kinetically limited redox reaction as demonstrated earlier, we show here that selenite is rapidly reduced within one day by nanoparticulate mackinawite and magnetite, while only one third of selenite is reduced by micrometer-sized siderite. Depending on Fe(II)-bearing phase and pH, we observed four different reaction products, red and gray elemental Se, and two iron selenides with structures similar to Fe7Se8 and FeSe. The thermodynamically most stable iron selenide, ferroselite (FeSe2), was not observed. The local structures of the reaction products suggest formation of nanoscale clusters, which may be prone to colloid-facilitated transport, and may have a higher than expected solubility.

  17. Macroscopic experimental and modeling evaluation of selenite and selenate adsorption mechanisms on gibbsite

    Science.gov (United States)

    Selenite Se(IV) and selenate Se(VI) adsorption behavior was investigated on gibbsite as a function of solution pH and solution ionic strength. Adsorption of both Se redox states decreased with increasing solution pH. Electrophoretic mobility measurements showed downward shifts in point of zero cha...

  18. Experimental Study and modelling of the Sorption of Selenite and Europium Onto Smectite and Illite Clays

    International Nuclear Information System (INIS)

    Missana, T.; Alonso, U.; Garcia-Gutierrez, M.

    2009-01-01

    This study provides a large set of experimental selenite sorption data for pure smectite and illite. Similar sorption behavior existed in both clays: linear within a large range of the Se concentrations investigated and independent of ionic strength. Selenite sorption was also analysed in the illite/smectite system with the clays mixed in two different proportions. The objective of the study was to provide the simplest model possible to fit the experimental data, a model also capable of describing selenite sorption in binary illite/smectite clay systems. Selenite sorption data were modeled using both a one-and a two-site non-electrostatic model that took into account the formation of two complexes at the edge sites of the clay. The complexation constants obtained by fitting sorption data of the individual minerals were incorporated into a model to predict the adsorption of selenium in the illite/ smectite mixtures; the models predictions were consistent with the experimental adsorption data. (Author) 42 refs

  19. Rhizobium selenitireducens proteins involved in the reduction of selenite to elemental selenium

    Science.gov (United States)

    Microbial based bioremediation barriers can remove the metalloid selenite (SeO3–2) from flowing groundwater. The organisms associated with the process include microorganisms from within the bacterial and archaeal domains that can reduce soluble SeO3–2 to the insoluble and reddish-colored elemental ...

  20. Cycling of oxyanion-forming trace elements in groundwaters from a freshwater deltaic marsh

    Science.gov (United States)

    Telfeyan, Katherine; Breaux, Alexander; Kim, Jihyuk; Kolker, Alexander S.; Cable, Jaye E.; Johannesson, Karen H.

    2018-05-01

    Pore waters and surface waters were collected from a freshwater system in southeastern Louisiana to investigate the geochemical cycling of oxyanion-forming trace elements (i.e., Mo, W, As, V). A small bayou (Bayou Fortier) receives input from a connecting lake (Lac des Allemands) and groundwater input at the head approximately 5 km directly south of the Mississippi River. Marsh groundwaters exchange with bayou surface water but are otherwise relatively isolated from outside hydrologic forcings, such as tides, storms, and effects from local navigation canals. Rather, redox processes in the marsh groundwaters appear to drive changes in trace element concentrations. Elevated dissolved S(-II) concentrations in marsh groundwaters suggest greater reducing conditions in the late fall and winter as compared to the spring and late summer. The data suggest that reducing conditions in marsh groundwaters initiate the dissolution of Fe(III)/Mn(IV) oxide/hydroxide minerals, which releases adsorbed and/or co-precipitated trace elements into solution. Once in solution, the fate of these elements is determined by complexation with aqueous species and precipitation with iron sulfide minerals. The trace elements remain soluble in the presence of Fe(III)- and SO42-- reducing conditions, suggesting that either kinetic limitations or complexation with aqueous ligands obfuscates the correlation between V and Mo sequestration in sediments with reducing or euxinic conditions.

  1. Rational evolution of the unusual Y-type oxyanion hole of Rhodococcus sp. CR53 lipase LipR.

    Science.gov (United States)

    Infanzón, Belén; Sotelo, Pablo H; Martínez, Josefina; Diaz, Pilar

    2018-01-01

    Rhodococcus sp CR-53 lipase LipR was the first characterized member of bacterial lipase family X. Interestingly, LipR displays some similarity with α/β-hydrolases of the C. antartica lipase A (CAL-A)-like superfamily (abH38), bearing a Y-type oxyanion hole, never found before among bacterial lipases. In order to explore this unusual Y-type oxyanion hole, and to improve LipR performance, two modification strategies based on site directed or saturation mutagenesis were addressed. Initially, a small library of mutants was designed to convert LipR Y-type oxyanion hole (YDS) into one closer to those most frequently found in bacteria (GGG(X)). However, activity was completely lost in all mutants obtained, indicating that the Y-type oxyanion hole of LipR is required for activity. A second approach was addressed to modify the two main oxyanion hole residues Tyr 110 and Asp 111 , previously described for CAL-A as the most relevant amino acids involved in stabilization of the enzyme-substrate complex. A saturation mutagenesis library was prepared for each residue (Tyr 110 and Asp 111 ), and activity of the resulting variants was assayed on different chain length substrates. No functional LipR variants could be obtained when Tyr 110 was replaced by any other amino acids, indicating that this is a crucial residue for catalysis. However, among the Asp 111 variants obtained, LipR D111G produced a functional enzyme. Interestingly, this LipR-YGS variant showed less activity than wild type LipR on short- or mid- chain substrates but displayed a 5.6-fold increased activity on long chain length substrates. Analysis of the 3D model and in silico docking studies of this enzyme variant suggest that substitution of Asp by Gly produces a wider entrance tunnel that would allow for a better and tight accommodation of larger substrates, thus justifying the experimental results obtained. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. METEOROLOGIE APPLIQUEE AUX SYSTEMES ENERGETIQUES

    OpenAIRE

    David, Mathieu

    2015-01-01

    Mes activités de recherche et d’enseignement au sein du laboratoire de Physique et Ingénierie Mathématique pour l’Énergie le bâtiment et l’environnemeNT (PIMENT), de l’École Supérieure d’Ingénieurs Réunion Océan Indien, de l’IUT de Saint-Pierre et de l’UFR Sciences de l’Homme et de l’Environnement de l’Université de La Réunion contribuent au développement de l’analyse météorologique appliquée aux systèmes énergétiques. En effet, la très grande majorité des systèmes énergétiques sont en intera...

  3. Screening and identification of efficient strain in selenium oxyanions sorption in order to biological wastewater treatment

    Directory of Open Access Journals (Sweden)

    fatemeh yaghoobizadeh

    2016-06-01

    Full Text Available Introduction: Selenium is an element with antioxidant activities that plays roles in thyroid hormone homeostasis, immunity and also fertility. Nevertheless, selenium toxicity (selenosis causes problems for humans such as abnormalities of the nervous system, gastrointestinal problems and hair loss. Thus, this study was performed with the aim of bacterial biosorbent isolation in order to remove selenium contaminant from wastewater. Materials and methods: In this research, at first using modified Luria- Bertani agar (mLBA medium with certain concentration of sodium selenate salt, isolation of bacterial isolates was done from three collected wastewater and sludge samples from Khouzestan industrial factories. After determination of minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC, the sorption capacity and the percentage of metal removal efficiency (%RE were investigated by atomic absorption spectrophotometer using metabolically active and inactive samples belonging to an efficient isolate. Identification was performed by morphological, biochemical and molecular methods. Results: Among 73 attained bacterial isolates at the first stage, 8 selenate oxyanion resistant isolates were gathered. Among these, AMS1-S8 isolate with MIC= 600­mM and MBC= 1200­mM were selected for more studies. Attained results in sorption mechanism determination stage showed that the sorption capacity in metabolically active sample is more than the inactive samples. Based on the identification results, it is revealed that this isolate belongs to the Enterobacter genus. This isolate is deposited as accession JQ965667 in the GeneBank database. Discussion and conclusion: The results showed that active biomass of selected isolate, have most sorption capacity and %RE and among the other isolates, have high partial resistance against selenate. Therefore, it can be a relatively ideal option for the bioremediation of polluted environments.

  4. Aux marges du monde arabe

    Directory of Open Access Journals (Sweden)

    Hélène Thiollet

    2004-09-01

    Full Text Available L’étude des migrations contemporaines des Érythréens vers le Yémen au tournant des années quatre-vingt-dix permet d’observer les transformations des dynamiques régionales à l’œuvre dans le monde arabe. Les migrations sont un phénomène sensible aux différents aspects (politiques, économiques, culturels, géographiques de l’intégration régionale. Celle si est envisagée dans cet article à travers une approche doublement marginale : -la marginalité géographique de l’Érythrée arabo-africaine et du Yémen, économi­quement isolé dans la péninsule Arabique, -l’étude des migrations formelles et informelles, élément souvent marginal dans l’étude des institutions et des échanges qui constituent un système régional intégré. Cette étude est fondée sur une série d’entretiens menés au Yémen entre février et avril 2002 auprès des administrations yéménites et de la population érythréenne.

  5. L'adaptation aux changements climatiques

    International Development Research Centre (IDRC) Digital Library (Canada)

    Cathy Egan

    plus équitables et plus prospères. Centre de recherches pour le développement international, CP 8500, Ottawa (Ontario) Canada K1G 3H9. Tél. : 613-236-6163 • Télécopieur : 613-238-7230 • Courriel : info@crdi.ca. L'ADAPTATION AUX. CHANGEMENTS CLIMATIQUES. LE RECOURS AUX. ONDES. Les petits exploitants ...

  6. Effects of sodium selenite supplementation on lead nitrate-induced oxidative stress in lung tissues of diabetic and non-diabetic rats

    OpenAIRE

    APAYDIN, Fatma; KALENDER, Suna; DEMİR, Filiz; BAŞ, Hatice

    2014-01-01

    In this study, diabetic and non-diabetic male rats were given to sodium selenite, lead nitrate and sodium selenite plus lead nitrate through gavage. At the end of the 4th week, lipid peroxidation and antioxidant enzyme activities was investigated compared to control group. No significant differences were observed between control and sodium selenite treated groups. By the end of the fourth week, lead nitrate led to increase the levels of MDA, and decrease in antioxidant activities compared wit...

  7. Acute selenium toxicity in lambs following intramuscular injection of sodium selenite

    Energy Technology Data Exchange (ETDEWEB)

    Caravaggi, C.; Clark, F.L.; Jackson, A.R.B.

    1970-01-01

    The LD50 in lambs from a farm where selenium deficiency has not been recorded was found to be 45..mu..g. of Se/kg. body weight when sodium selenite was administered as a single intramuscular injection. Marked pulmonary congestion and oedema were constantly present with degenerative changes in liver and kidney. A similarity was noted between the autopsy findings of acute selenosis and those described for enterotoxaemia. 13 references, 4 figures.

  8. Relationship between blood-retinal barrier development and formation of selenite nuclear cataract in rat

    Directory of Open Access Journals (Sweden)

    Ping Lu

    2017-12-01

    Full Text Available AIM: To investigate the relationship between development of blood-retinal barrier and formation of selenite nuclear cataract in rat. METHODS: Activity of GPx, MDA level in lens and selenium content in the eyeballs of different ages rats were determined. Besides, lanthanum hydroxide \\〖La(OH3\\〗 tracer method was used to detect development status of blood-retina barrier at different ages. RESULTS: The result showed that the enzyme activity of GPx was highest in young rats before open eyes, but then decreased gradually with age. Distribution of La(OH3 in retinal pigment epithelial layer of 20-day-old rats was significantly less than 11-day-old rats. Injecting sodium selenite to 9-day-old rats, lanthanum hydroxide increased obviously and extended to the inner layers of the retina after 48h, and the retinal pigment epithelial layer was damaged seriously; while injecting sodium selenite to 18-day-old rats with the same dose, number of lanthanum hydroxide decreased significantly and did not extend to the inner layer after 48h.Before opening eyes, the content of MDA in the lens of rats was the highest, and decreased significantly after opening eyes. The Se group was 5 times as that of the control group. Besides, in these groups of rats, selenium content in the eyeballs and MDA level in the lens were in agreement with the change of La(OH3 distribution. CONCLUSION: These results indicated that antioxidant capacity in the eyelid unopened rats is not the main reason for selenite induced cataract formation. The real reason is that blood-retina barrier development is not mature in the eyelid unopened rats.

  9. In vitro uptake of 75Se-selenite by lens of young and adult rats

    International Nuclear Information System (INIS)

    Sladkova, J.; Ostadalova, I.; Babicky, A.; Obenberger, J.

    1988-01-01

    The uptake was observed of 75 Se-selenite by the lens in Wistar strain rats in adult animals, in 17-day old rats kept with their mothers and in prematurely weaned rats. Also measured was the excretion of 75 Se by the lens of young and adult rats following incubation in the medium with radioselenium. The metabolites were analysed which were discharged by the lens containing 75 Se. In Brattleboro rats the uptake of 75 Se-selenite was also measured by the lens in young and adult rats. The uptake of 75 Se-selenite by the lens in young Wistar rats was found to be 1.6 times higher than by the lens of adult rats and the time course of the radioselenium uptake was slightly different. In the lens of prematurely weaned rats no significant difference was found in the uptake of radioselenium after 4 hours as compared with rats of the same age kept with their mothers. In homozygous Brattleboro rats, a higher uptake of 75 Se-selenite was found as compared with both young and adult heterozygous rats. The time course and the quantity of 75 Se efflux from the lens of young and adult Wistar rats differed significantly after 0.5 hour of pre-incubation. From metabolites containing 75 Se excreted by the lens following preincubation, glutathione selenotrisulfide and a not yet accurately determined fraction with a large share of radioactivity were isolated. The stated results provide yet more proof that selenium cataract is a manifestation of the ontogenic dependence of selenium metabolism in the lens and in the entire organism. (author). 4 tabs., 30 refs

  10. Potassium vanadium selenite, K(VO2)3(SeO3)2

    International Nuclear Information System (INIS)

    Harrison, W.T.A.; Dussack, L.L.; Jacobson, A.J.

    1995-01-01

    The hydrothermal synthesis and single-crystal structure of potassium vanadium(V) selenite, K(VO 2 ) 3 (SeO 3 ) 2 , are reported. K(VO 2 ) 3 (SeO 3 ) 2 is a layered phase based on a hexagonal tungsten-oxide-like array of corner-sharing VO 6 octahedra capped by Se atoms, and is isostructural with NH 4 (VO 2 ) 3 (SeO 3 ) 2 . (orig.)

  11. Determination of glutathione in apoptotic SMMC-7221 cells induced by xylitol selenite using capillary electrophoresis.

    Science.gov (United States)

    Wu, Xue; Cao, Yu; Zhang, Jian; Lei, Ming; Deng, Xiaojie; Zahid, Kashif Rafiq; Liu, Yanli; Liu, Ke; Yang, Jihong; Xiong, Guomei; Yao, Hanchao; Qi, Chao

    2016-05-01

    To determine the glutathione (GSH) content in a human hepatoma cell line (SMMC-7221) treated with xylitol/selenite, providing a part of an investigation of its anti-cancer mechanisms. The nuclei of SMMC-7221 cells were stained with Hoechst 33258 in an apoptosis assay, and their morphology subsequently changed from circular to crescent shape. The calibration curve (r(2) = 0.992) was established, and GSH content markedly decreased after treated with 0.5 and 1 mg xylitol/selenite l(-1) for 12, 36 and 60 h (12 h: from 95.57 ± 19.57 to 29.09 ± 7.74 and 24.27 ± 11.15; 36 h: from 70.73 ± 11.35 to 19.54 ± 6.39 and 9.35 ± 6.69; 60 h: from 72.63 ± 16.94 to 7.432 ± 3.84 and 0). The depletion rate of GSH was more related to the concentration of xylitol/selenite than the treatment time (from 69.95 ± 1.87 to 100 % vs. 0.22 ± 0.2 to 100 %). Xylitol/selenite is a promising anti-cancer drug to induce apoptosis in SMMC-7221 cells. It may regulate the apoptosis through the co-action of multiple mechanisms related to GSH depletion.

  12. Prophylactic Action of Sodium Selenite against Gamma Radiation in Different Tissues of Rats

    International Nuclear Information System (INIS)

    Said, U.Z.; El-Tahawy, N.A.

    2001-01-01

    Whole body gamma-irradiation of rats at a single dose of 5Gy significantly increased the levels of collagen and lipid peroxides in lung and kidney tissues. The increase started from the 1st up to the 4th week in case of lung tissues, while, from the 2nd up to the 4th week in case of kidney tissues. The increase in serum urea and serumcreatinine contents were also recorded all times post irradiation. Intraperitoneal injection of sodium selenite, (0.25 mg/kg body weight) for 20 days before exposure to radiation, significantly reduced the increase of collagen and lipid peroxide contents in lung and kidney tissues. Significant protection was also recorded for the increases in the contents of serum urea and serum creatinine from the 2nd up to the 4th week after irradiation. Accordingly, it could be concluded that sodium selenite has exerted a protective role against radiation- induced changes in the contents of collagen and lipid peroxides in lung and kidney tissues. Sodium selenite also induced protection against radiation-induced increase in urea and creatinine levels in the serum

  13. [The protective effects of sodium selenite and aloin against ultraviolet A radiation].

    Science.gov (United States)

    Guo, Yu; Ji, Ran; Lü, Xi; Wan, Yi-feng; Jiang, Xian

    2011-01-01

    To investigate the protective effects of sodium selenite and aloin against ultraviolet A (UVA) radiation on the dermal fibroblasts including the suppression of proliferation, oxidative damage and collagen synthesis. Human dermal fibroblasts were divided into the negative control group, the positive control UVA radiation group, the sodium selenite treatment plus UVA radiation group and the aloin treatment plus UVA radiation group, which were incubated with sodium selenite or aloin and irradiated with 5 J/cm2 UVA respectively. The MTT spectrophotometry and biochemical assay were used to determine the proliferation, collagen level and the SOD and GSH-Px activity of the fibroblast cells after radiation. 5 J/cm2 UVA affect the proliferation, collage protein, SOD and GSH-Px activity in the fibroblast cells (P aloin (1-100 mg/L) could enhance the proliferation and the SOD and GSH-Px activity. A increased collagen synthesis in dose dependant manner was also observed (P aloin in a certain range of concentration have protective effects on ultraviolet radiation induced fibroblast proliferation inhibition, oxidative injury, and decreased collagen synthesis.

  14. Evaluation of anticataract potential of Triphala in selenite-induced cataract: In vitro and in vivo studies

    Directory of Open Access Journals (Sweden)

    Suresh Kumar Gupta

    2010-01-01

    Full Text Available Triphala (TP is composed of Emblica officinalis, Terminalia chebula, and Terminalia belerica. The present study was undertaken to evaluate its anticataract potential in vitro and in vivo in a selenite-induced experimental model of cataract. In vitro enucleated rat lenses were maintained in organ culture containing Dulbecco′s Modified Eagles Medium alone or with the addition of 100΅M selenite. These served as the normal and control groups, respectively. In the test group, the medium was supplemented with selenite and different concentrations of TP aqueous extract. The lenses were incubated for 24 h at 37°C. After incubation, the lenses were processed to estimate reduced glutathione (GSH, lipid peroxidation product, and antioxidant enzymes. In vivo selenite cataract was induced in 9-day-old rat pups by subcutaneous injection of sodium selenite (25 μmole/kg body weight. The test groups received 25, 50, and 75 mg/kg of TP intraperitoneally 4 h before the selenite challenge. At the end of the study period, the rats′ eyes were examined by slit-lamp. TP significantly (P < 0.01 restored GSH and decreased malondialdehyde levels. A significant restoration in the activities of antioxidant enzymes such as superoxide dismutase (P < 0.05, catalase (P < 0.05, glutathione peroxidase (P < 0.05, and glutathione-s-transferase (P < 0.005 was observed in the TP-supplemented group compared to controls. In vivo TF 25mg/kg developed only 20% nuclear cataract as compared to 100% in control. TP prevents or retards experimental selenite-induced cataract. This effect may be due to antioxidant activity. Further studies are warranted to explore its role in human cataract.

  15. Ionic flotation of complexing oxyanions. Thermodynamics of uranyl complexation in a sulfuric medium. Definition of selectivity conditions of the process

    International Nuclear Information System (INIS)

    Bouzat, G.

    1987-01-01

    Oxyanion ionic flotation process with dodecylamine hydrochloride as collector is studied by investigation of flotation and filtration recovery curves, suspension turbidity, conductimetric measurements, and solubility of ionic species. The process is controlled by chemical reactions of precipitation and by adsorption of surfactant confering hydrophobic or hydrophilic surface properties to the solid phase respectively when one or two monolayers of surfactant are successively adsorbed. Equilibrium constants (in terms of activity) of the uranium (VI) complexation with sulphate oxyanions are calculated through Raman spectroscopic study of uranyl sulphate aqueous solutions. The complexation results in a shift of the symmetrical stretching vibration band of U0 2 to low wavenumbers and an increase of their cross section. The solubility curves of ionic species in the precipitation of uranyl -sulphate complexes by dodecylamine hydrochloride are modelled. The knowledge of solubility products, activity coefficients of the species and critical micellar concentration of the surfactant allow the modelling of flotation recovery curves. Temperature and collector structure modifications are studied in terms of optimization parameters and uranium extraction of mine drainage water is processed. Residual concentration of surfactant is considerably lowered by adsorption on montmorillonite

  16. The infrared spectra and structure of acetylsalicylic acid (aspirin) and its oxyanion: an ab initio force field treatment

    Science.gov (United States)

    Binev, I. G.; Stamboliyska, B. A.; Binev, Y. I.

    1996-05-01

    The structures of acetylsalicylic acid (aspirin) (I) and its oxyanion (II) have been studied by means of infrared spectra and ab initio 3-21 G force field calculations. The 3100-1100 cm -1 region bands of both the aspirin molecule and its oxyanion have been assigned. The theoretical infrared data for the free aspirin anion are in good agreement with the experimental data for aspirin alkali-metal salts in dimethyl sulfoxide- d6. The theoretical geometrical parameters for the isolated aspirin molecule are close to the literature X-ray diffraction data for its dimer in the solid state, except for those of the carboxy group, which participates directly in hydrogen bond formation. The changes in both the spectral and geometrical parameters, caused by the conversion of the aspirin molecule into the anion, are essential, but they are localized mainly within the carboxy group and the adjacent C-Ph bond. This is also true for the changes in the corresponding bond indices and electronic charges.

  17. Multi-competitive interaction of As(III) and As(V) oxyanions with Ca2+, Mg2+, PO4 3-, and CO3 2- ions on goethite

    NARCIS (Netherlands)

    Stachowicz, M.; Hiemstra, T.; Riemsdijk, van W.H.

    2008-01-01

    Complex systems, simulating natural conditions like in groundwater, have rarely been studied, since measuring and in particular, modeling of such systems is very challenging. In this paper, the adsorption of the oxyanions of As(III) and As(V) on goethite has been studied in presence of various

  18. Adsorption of oxyanions of As, B, Cr, Mo and Se from coal fly ash leachates using Al3+/Fe3+modified bentonite clay

    CSIR Research Space (South Africa)

    Vhahangwele, M

    2013-01-01

    Full Text Available ponds. On disposal, coal fly ash leaches out toxic chemical species on contact with the aqueous media hence posing hazardous effects to the aquatic and terrestrial environment. Of prime concern are Oxyanionic species such as As, B, Cr, Mo and Se...

  19. Quantification of low molecular weight selenium metabolites in human plasma after treatment with selenite in pharmacological doses by LC-ICP-MS

    DEFF Research Database (Denmark)

    Flouda, Konstantina; Dersch, Julie Maria; Gabel-Jensen, Charlotte

    2016-01-01

    , and limits of detection and quantitation with satisfactory results. The method was applied for analysis of a set of plasma samples from cancer patients receiving selenite treatment in a clinical trial. Three LMW selenium compounds were observed. The main compounds, SeGal and selenite were tentatively...

  20. Extracellular thiol-assisted selenium uptake dependent on the x(c)(-) cystine transporter explains the cancer-specific cytotoxicity of selenite

    DEFF Research Database (Denmark)

    Olm, E.; Fernandes, A. P.; Hebert, C.

    2009-01-01

    The selenium salt selenite (SeO32-) is cytotoxic in low to moderate concentrations, with a remarkable specificity for cancer cells resistant to conventional chemotherapy. Our data show that selenium uptake and accumulation, rather than intracellular events, are crucial to the specific selenite...

  1. Determination of selenite and selenate in human urine by ion chromatography and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Jons, O.

    2000-01-01

    The selenium species selenite, selenate and selenomethionine were separated in aqueous solution by ion chromatography. The separation was performed on an IonPac AG11 in series with an AS11 anion exchange column by elution with 25 mM sodium hydroxide in 2% methanol. The Se-78 and Se-82 isotopes were...... monitored in the inductively coupled plasma mass spectrometry (ICP-MS) detector. When the chromatographic system was applied to analysis of urine samples diluted 1 + 1, the selenomethionine signal appeared in the front together with other unresolved selenium species, while the selenite and selenate signals...... and selenate, respectively, corresponding to absolute amounts of 8 and 16 pg, respectively. Calculations were based on peak height measurements of the Se-82 isotope. In 23 analysed urine samples, the concentration of selenite was in the range selenium...

  2. Effects of 14-day oral low dose selenium nanoparticles and selenite in rat—as determined by metabolite pattern determination

    Directory of Open Access Journals (Sweden)

    Niels Hadrup

    2016-10-01

    Full Text Available Selenium (Se is an essential element with a small difference between physiological and toxic doses. To provide more effective and safe Se dosing regimens, as compared to dosing with ionic selenium, nanoparticle formulations have been developed. However, due to the nano-formulation, unexpected toxic effects may occur. We used metabolite pattern determination in urine to investigate biological and/or toxic effects in rats administered nanoparticles and for comparison included ionic selenium at an equimolar dose in the form of sodium selenite. Low doses of 10 and 100 fold the recommended human high level were employed to study the effects at borderline toxicity. Evaluations of all significantly changed putative metabolites, showed that Se nanoparticles and sodium selenite induced similar dose dependent changes of the metabolite pattern. Putative identified metabolites included increased decenedioic acid and hydroxydecanedioic acid for both Se formulations whereas dipeptides were only increased for selenite. These effects could reflect altered fatty acid and protein metabolism, respectively.

  3. Sodium Selenite Acts as an Otoprotectant against Neomycin-Induced Hair Cell Damage in a Zebrafish Model.

    Directory of Open Access Journals (Sweden)

    Jiwon Chang

    Full Text Available Sodium selenite is a trace element essential for many physiological functions in the body. It is involved in various biological processes; it acts as a cofactor for antioxidant enzymes that protect against free radicals and is reported to limit metal-mediated oxidative DNA damage. In the present study, we investigated the effect of sodium selenite on neomycin ototoxicity in wild-type and transgenic zebrafish (Brn3C: EGFP. Five or six days post-fertilization, zebrafish larvae were co-exposed to 125 μM neomycin and various concentrations (10 μM, 100 μM, 250 μM, and 500 μM of sodium selenite for 1 h. Hair cells within neuromasts of the supraorbital (SO1 and SO2, otic (O1, and occipital (OC1 lateral lines were analyzed by fluorescence microscopy (n = 10 fish per treatment. Hair cell survival was estimated as the ratio of the hair cell numbers in each group compared to those of the control group that were not exposed to neomycin. Apoptosis and hair cell damage of neuromasts were evaluated using the terminal deoxynucleotidyl transferase (TdT-mediated dUTP-biotin nick end labeling (TUNEL assay and 2-[4-(dimethylamino styryl]-N-ethylpyridinium iodide (DASPEI assay, respectively. Ultrastructural changes were evaluated using scanning electron microscopy and transmission electron microscopy. Neuromast hair cells were preserved in zebrafish exposed to 125 μM neomycin and 500 μM sodium selenite for 1 h. Sodium selenite protected against neomycin-induced hair cell loss of neuromasts, reduced apoptosis, and prevented zebrafish ultrastructural changes. We propose that sodium selenite protects against neomycin-induced hair cell damage by inhibiting apoptosis, decreasing the disarray of stereocilia, and preventing ultrastructural changes in the neuromast hair cells of the zebrafish.

  4. Thermally-Induced Chemistry and the Jovian Icy Satellites: A Laboratory Study of the Formation of Sulfur Oxyanions

    Science.gov (United States)

    Loeffler, Mark J.; Hudson, Reggie L.

    2011-01-01

    Laboratory experiments have demonstrated that magnetospheric radiation in the Jovian system drives reaction chemistry in ices at temperatures relevant to Europa and other icy satellites. Here we present new results on thermally-induced reactions at 50-100 K in solid H2O-SO2 mixtures, reactions that take place without the need for a high-radiation environment. We find that H2O and SO2 react to produce sulfur Oxyanions, such as bisulfite, that as much as 30% of the SO2 can be consumed through this reaction, and that the products remain in the ice when the temperature is lowered, indicating that these reactions are irreversible. Our results suggest that thermally-induced reactions can alter the chemistry at temperatures relevant to the icy satellites in the Jovian system.

  5. Accès aux ressources internationales aux fins de la lutte antitabac ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Accès aux ressources internationales aux fins de la lutte antitabac en Bolivie : obstacles et possibilités. Malgré certains succès remportés en matière de lutte antitabac à l'échelle nationale et internationale, on dispose de peu de données probantes sur le financement ou le soutien international à cet égard dans les pays en ...

  6. Participation des hommes aux soins aux enfants avant la mise en ...

    African Journals Online (AJOL)

    Participation des hommes aux soins aux enfants avant la mise en oeuvre de la composante familiale et communautaire de la stratégie «prise en charge intégrée des ... Aim : The purpose of this study was to assess the role played by the men in front of child illness before the implementation of the family and community ...

  7. Selenium intoxication with selenite broth resulting in acute renal failure and severe gastritis

    Directory of Open Access Journals (Sweden)

    Kamble P

    2009-01-01

    Full Text Available Selenium (Se is an essential trace element in human and animal nutrition. It is also widely utilized in industrial processes. Reports of acute selenium toxicity in humans are rare. We report a case of a 23-year-old female who consumed about 100 mL of liquid selenite broth and presented with severe nausea, vomiting, abdominal pain, hematemesis and acute renal failure (ARF. The serum selenium level was significantly increased. Gastro-duodenoscopy revealed severe corrosive gastritis. Renal biopsy showed features of acute tubular necrosis (ATN, affecting primarily the proximal tubules. The patient was managed with gastric lavage, blood transfusions, infusion of fresh frozen plasma (FFP and platelet concentrates and hemo-dialysis. The patient was discharged five weeks after admission and her renal functions reco-vered completely by eight weeks after admission. She continues to be on regular follow-up for any possible sequelae of mucosal corrosive damage. This case highlights a case of selenium intoxication from selenite broth resulting in ARF and corrosive gastritis. The recovery was complete.

  8. Separation of Selenite from Inorganic Selenium Ions using TiO{sub 2} Magnetic Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jongmin; Lim, H. B. [Donkook Univ., Yongin (Korea, Republic of)

    2013-11-15

    A simple and quick separation technique for selenite in natural water was developed using TiO{sub 2} SiO{sub 2}/Fe{sub 3}O{sub 4} nanoparticles. For the synthesis of nanoparticles, a polymer-assisted sol-gel method using hydroxypropyl cellulose (HPC) was developed to control particle dispersion in the synthetic procedure. In addition, titanium butoxide (TBT) precursor, instead of the typical titanium tetra isopropoxide, was used for the formation of the TiO{sub 2} shell. The synthesized nanoparticles were used to separate selenite (Se{sup 4+}) in the presence of Se{sup 6+} or selenium anions for the photocatalytic reduction to Se{sup 0} atom on the TiO{sub 2} shell, followed by magnetic separation using Fe{sub 3}O{sub 4} nanoparticles. The reduction efficiency of the photocatalytic reaction was 81.4% at a UV power of 6W for 3 h with a dark adsorption of 17.5% to the nanoparticles, as determined by inductively coupled plasma-mass spectrometry (ICP-MS). The developed separation method can be used for the speciation and preconcentration of selenium cations in environmental and biological analysis.

  9. Nanocrystalline hydroxyapatite enriched in selenite and manganese ions: physicochemical and antibacterial properties

    Science.gov (United States)

    Kolmas, Joanna; Groszyk, Ewa; Piotrowska, Urszula

    2015-07-01

    In this work, we used the co-precipitation method to synthesize hydroxyapatite (Mn-SeO3-HA) containing both selenium IV (approximately 3.60 wt.%) and manganese II (approximately 0.29 wt.%). Pure hydroxyapatite (HA), hydroxyapatite-containing manganese (II) ions (Mn-HA), and hydroxyapatite-containing selenite ions alone (SeO3-HA), prepared with the same method, were used as reference materials. The structures and physicochemical properties of all the obtained samples were investigated. PXRD studies showed that the obtained materials were homogeneous and consisted of apatite phase. Introducing selenites into the hydroxyapatite crystals considerably affects the size and degree of ordering. Experiments with transmission electron microscopy (TEM) showed that Mn-SeO3-HA crystals are very small, needle-like, and tend to form agglomerates. Fourier transform infrared spectroscopy (FT-IR) and solid-state nuclear magnetic resonance (ssNMR) were used to analyze the structure of the obtained material. Preliminary microbiological tests showed that the material demonstrated antibacterial activity against Staphylococcus aureus, yet such properties were not confirmed regarding Escherichia coli. PACS codes: 61, 76, 81

  10. Molecular structure, vibrational, HOMO-LUMO, MEP and NBO analysis of hafnium selenite

    Science.gov (United States)

    Yankova, Rumyana; Genieva, Svetlana; Dimitrova, Ginka

    2017-08-01

    In hydrothermal condition hafnium selenite with estimated chemical composition Hf(SeO3)2·n(H2O) was obtained and characterized by powder X-Ray diffraction, IR spectroscopy and thermogravimetrical analysis. The composition of the obtained crystalline phase was established as dihydrate of tetraaqua complex of the hafnium selenite [Hf(SeO3)2(H2O)4]·2H2O. The results of the thermogravimetrical analysis are shown that the two hydrated water molecules are released in the temperature interval 80-110°C, while the four coordinated water molecules - at 210-300°C. By DFT method, with Becke's three parameter exchange-functional combined with gradient-corrected correlation functional of Lee, Yang and Parr and 6-31G(d), 6-311 + G(d,p) basis sets and LANL2DZ for Hf atom were calculated the molecular structure, vibrational frequencies and thermodynamic properties of the structure. The UV-Vis spectra and electronic properties are presented. The energy and oscillator strength calculated by time-dependent density functional theory corresponds well with the experimental ones. Molecular electrostatic potential (MEP) was performed. Mulliken population analysis on atomic charges was also calculated. The stability and intramolecular interactions are interpreted by NBO analysis.

  11. Selenium intoxication with selenite broth resulting in acute renal failure and severe gastritis.

    Science.gov (United States)

    Kamble, P; Mohsin, N; Jha, A; Date, A; Upadhaya, A; Mohammad, E; Khalil, M; Pakkyara, A; Budruddin, M

    2009-01-01

    Selenium (Se) is an essential trace element in human and animal nutrition. It is also widely utilized in industrial processes. Reports of acute selenium toxicity in humans are rare. We report a case of a 23-year-old female who consumed about 100 mL of liquid selenite broth and presented with severe nausea, vomiting, abdominal pain, hematemesis and acute renal failure (ARF). The serum selenium level was significantly increased. Gastro-duodenoscopy revealed severe corrosive gastritis. Renal biopsy showed features of acute tubular necrosis (ATN), affecting primarily the proximal tubules. The patient was managed with gastric lavage, blood transfusions, infusion of fresh frozen plasma (FFP) and platelet concentrates and hemo-dialysis. The patient was discharged five weeks after admission and her renal functions recovered completely by eight weeks after admission. She continues to be on regular follow-up for any possible sequelae of mucosal corrosive damage. This case highlights a case of selenium intoxication from selenite broth resulting in ARF and corrosive gastritis. The recovery was complete.

  12. Nephrotoxic effects of lead nitrate exposure in diabetic and nondiabetic rats: Involvement of oxidative stress and the protective role of sodium selenite.

    Science.gov (United States)

    Baş, Hatice; Kalender, Yusuf

    2016-10-01

    Heavy metals are known to be toxic to organisms. The present study was undertaken to evaluate the protective effect of sodium selenite against lead nitrate (LN)-induced nephrotoxicity in diabetic and nondiabetic rats. Animals were divided into eight groups where the first was served as a control, whereas the remaining groups were treated with sodium selenite (1 mg/kg b.w.), LN (22.5 mg/kg b.w.) and a combination of LN and sodium selenite and diabetic forms of these groups. Changes in antioxidant enzyme activities, malondialdehide levels, serum urea, uric acid, creatinine levels, body, and kidney weights and histopathological changes were determined after 28 days. LN caused severe histopathological changes, increment in urea, uric acid, creatinine, and MDA levels, also decreasing in antioxidant enzyme activities, body, and kidney weights. In sodium selenite + LN group, we observed the protective effect of sodium selenite on examining parameters. Also diabetes caused alterations on these parameters compared with nondiabetic animals. We found that sodium selenite did not show protective effect on diabetes caused damages. As a result, LN caused nephrotoxicity and sodium selenite alleviated this toxicity but sodium selenite did not protect kidneys against diabetes mediated toxicity. Also, LN caused more harmfull effects in diabetic groups compared with nondiabetic groups. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1229-1240, 2016. © 2015 Wiley Periodicals, Inc.

  13. Honoraires versés aux gouverneurs

    International Development Research Centre (IDRC) Digital Library (Canada)

    André Lavoie

    Pour tous les gouverneurs à l'exclusion du président du Conseil : 410 CAD par jour;. • Pour le président du Conseil : 420 CAD par jour; b) Pour ce qui est de la préparation, la présence et la participation aux réunions des comités du. Conseil, les honoraires des gouverneurs doivent être versés selon des taux équivalant à la ...

  14. Adaptation aux changements climatiques dans les zones ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Adaptation aux changements climatiques dans les zones périurbaines de l'Asie du Sud-Est. La croissance rapide des zones périurbaines de l'Asie du Sud-Est est caractérisée par un manque de services de base, des milieux bâtis non planifiés et la relative faiblesse des gouvernements. Les habitants de ces zones sont ...

  15. Aux origines de la science moderne

    CERN Document Server

    Rossi, Paolo

    1999-01-01

    Aux origines de la science moderne. " Lorsque l'on aborde l'étude d'une pensée qui n'est plus la nôtre, il est important de chercher à oublier ce que nous savons ou croyons savoir. " Pour appréhender cette période fondatrice que fut la Révolution scientifique du XVIIe siècle en Europe, Paolo Rossi nous replonge dans des atmosphères intellectuelles et des modes de pensée depuis longtemps disparus. Des secrets hermétiques aux calculs mathématiques, de la magie au magnétisme et des cabinets de curiosité aux premières académies des sciences défilent ainsi des notions et des individus qui, remis en toute simplicité dans le contexte de leur époque, retrouvent une épaisseur et un sens nouveaux. Ainsi racontée sous la forme d'une histoire des idées, l'histoire des sciences devient accessible à tous.

  16. Explorations of new selenites of the group IIIA and IVA metals

    International Nuclear Information System (INIS)

    Kong Fang; Li Peicin; Zhang Suyun; Mao Jianggao

    2012-01-01

    Systematic explorations of new phases in the Ga III /In III /Ge IV –Se IV –O systems by hydrothermal syntheses or solid-state reactions at high-temperature led to six new ternary compounds, namely, M 2 Se 2 O 7 (M=Ga 1, In 2), M(OH)(SeO 3 ) (M=Ga 3, In 4), α-Ge(SeO 3 ) 2 5 and β-Ge(SeO 3 ) 2 6. Ga 2 Se 2 O 7 1 displays a 3D open framework composed of 2D gallium oxide layers being further bridged and capped by SeO 3 groups. In 2 Se 2 O 7 2 features a 3D indium oxide framework formed by corner- and edge- sharing InO 6 octahedra with SeO 3 groups attached on the cavities and the 8-member ring tunnels of the structure. The isostructural of M(OH)(SeO 3 ) (M=Ga 3, In 4) exhibit a 2D metal selenite layer composed of 1D edge-sharing MO 6 octahedral chains that are interconnected by SeO 3 groups. α-Ge(SeO 3 ) 2 (P2 1 /n) 5 displays a 3D open framework with 1D 8-member ring tunnels along the a-axis while β-Ge(SeO 3 ) 2 (Pa-3) 6 exhibits a condensed 3D network. - Graphical abstract: Highlights: ► Up to now, selenites of the group IIIA and IVA metals are still rare. ► Hydrothermal or solid state reactions yielded six new compounds in this system. ► They are M 2 Se 2 O 7 (M=Ga, In), M(OH)(SeO 3 ) (M=Ga, In), α-Ge(SeO 3 ) 2 and β-Ge(SeO 3 ) 2 . ► They exhibit four different 3D and one 2D structural types. ► α-Ge(SeO 3 ) 2 and β-Ge(SeO 3 ) 2 represent the first examples of germanium selenites.

  17. Effects of Foliar Selenite on the Nutrient Components of Turnip (Brassica rapa var. rapa Linn.

    Directory of Open Access Journals (Sweden)

    Xiong Li

    2018-03-01

    Full Text Available We administered foliar applications of 50, 100, and 200 mg L−1 selenium (Se, selenite on turnip (Brassica rapa var. rapa Linn. and detected the changes in the main nutrient components in fleshy roots. Results showed that the foliar application of Se (IV significantly increased the Se content in turnip, and Se (IV positively affected the uptake of several mineral elements, including magnesium, phosphorus, iron, zinc, manganese, and copper. Se (IV treatments also improved the synthesis of protein and multiple amino acids instead of crude fat and total carbohydrate in turnip, indicating that the foliar application of Se (IV could enhance Se biofortification in turnip and promote its nutritional value. We recommended 50–100 mg L−1 Se treatment for foliar application on turnip based on the daily intake of Se for adults (96–139 μg person−1 day−1 and its favorable effects on the nutrient components of turnip.

  18. Syntheses, structures and characterizations of three novel vanadium selenites with organically bonded copper/nickel complex

    International Nuclear Information System (INIS)

    Qian, Cheng; Kong, Fang; Mao, Jiang-Gao

    2016-01-01

    A series of vanadium selenites covalently bonded with metal-organic complex, namely, Ni(2,2-bipy) 2 V 2 O 4 (SeO 3 ) 2 (1), Cu(2,2-bipy)V 2 O 4 (SeO 3 ) 2 ·0.5H 2 O (2) and Cu 2 (2,2-bipy) 2 V 5 O 12 (SeO 3 ) 2 (3) (2,2-bipy=2,2-bipyridine) have been hydrothermally synthesized and structurally characterized. They exhibit three different structural dimensions, from 0D cluster, 1D chain to 2D layer. Compound 1 features a 0D {Ni(2,2-bipy) 2 V 2 O 4 (SeO 3 ) 2 } 2 dimeric cluster composed of two {Ni(2,2-bipy) 2 } 2+ moieties connected by the {V 4 O 8 (SeO 3 ) 4 } 4- cluster. Compound 2 shows a 1D {Cu(2,2-bipy)V 2 O 4 (SeO 3 ) 2 } n chain in which the {Cu 2 (2,2-bipy) 2 } 4+ moieties are bridged by the {V 4 O 8 (SeO 3 ) 4 } 4− clusters. Compound 3 displays a 2D structure consisted of mixed valence vanadium selenites layers {V IV V V 4 Se IV 2 O 18 } n 4− and {Cu(2,2-bipy)} 2+ complex moieties. The adjacent layers are further interconnected via π-π interactions between the 2,2-bipy ligands exhibiting an interesting 3D supramolecular architecture. Both compound 1 and 2 contain a new {V 4 O 8 (SeO 3 ) 4 } 4− cluster and compound 3 exhibits the first 2D vanadate polyhedral layer in vanadium selenites/tellurites with organic moieties. - Graphical abstract: We got three new vanadium selenites with organically linked copper/nickel complex, namely, Ni(2,2-bipy) 2 V 2 O 4 (SeO 3 ) 2 (1), Cu(2,2-bipy)V 2 O 4 (SeO 3 ) 2 ·0.5H 2 O (2) and Cu 2 (2,2-bipy) 2 V 5 O 12 (SeO 3 ) 2 (3) by hydrothermally syntheses. They display three different structural dimensions, from 0D cluster, to 1D chain and 2D layer. Display Omitted - Highlights: • Three new compounds display three different structural dimensions, from 0D cluster, to 1D chain and 2D layer. • The Tetranuclear {V 4 O 8 (SeO 3 ) 4 } 4− cluster and the vanadate {V 5 O 17 } n 2D layer are observed firstly. • Optical Properties and Magnetic Properties of three compounds are reported.

  19. Survival of Tribolium confusum (Coleoptera: Tenebrionidae) in basal-casein medium supplemented with sodium selenite

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, G.R.; Cole, B.S. (East Texas State Univ., Commerce (USA))

    1988-01-01

    The trace substance selenium is known to influence several systems exhibiting a high rate of cellular proliferation. Data are reported on survival patterns and times in various developmental stages of Tribolium confusum Duval reared in a defined medium supplemented with sodium selenite. Insects reared from eggs hatching in a selenium medium (Se medium) show a prolonged time in the larval period and marked larval mortality compared with those reared on unsupplemented medium. Adults emerging in an Se medium show reduced survival compared with adults transferred to such medium 1 wk after emergence. Larval survival patterns mimic those of the adult, whereby younger larvae that are transferred to Se medium appear to be more sensitive than those exposed to Se medium later in the larval stage. Transfer of Se medium-reared adults to unsupplemented medium as pupae has a beneficial effect on survival compared with adults that emerged in Se medium 1 wk before transfer.

  20. Protective Roles of Sodium Selenite against Aflatoxin B1-Induced Apoptosis of Jejunum in Broilers

    Directory of Open Access Journals (Sweden)

    Xi Peng

    2014-12-01

    Full Text Available The effects of aflatoxin B1 (AFB1 exposure and sodium selenite supplementation on cell apoptosis of jejunum in broilers were studied. A total of 240 one-day-old male AA broilers were randomly assigned four dietary treatments containing 0 mg/kg of AFB1 (control, 0.3 mg/kg AFB1 (AFB1, 0.4 mg/kg supplement Se (+ Se and 0.3 mg/kg AFB1 + 0.4 mg/kg supplement Se (AFB1 + Se, respectively. Compared with the control broilers, the number of apoptotic cells, the expression of Bax and Caspase-3 mRNA were significantly increased, while the expression of Bcl-2 mRNA and the Bcl-2/Bax ratio were significantly decreased in AFB1 broilers. The number of apoptotic cells and the expression of Caspase-3 mRNA in AFB1 + Se broilers were significantly higher than those in the control broilers, but significantly lower than those in AFB1 broilers. There were no significant changes in the expression of Bax mRNA between AFB1 + Se and control broilers; the expression of Bcl-2 mRNA and the Bcl-2/Bax ratio in AFB1 + Se broilers were significantly lower than those in the control broilers, but significantly higher than those in AFB1 broilers. In conclusion, 0.3 mg/kg AFB1 in the diet can increase cell apoptosis, decrease Bcl-2 mRNA expression, and increase of Bax and Caspase-3 mRNA expression in broiler’s jejunum. However, supplementation of dietary sodium selenite at the concentration of 0.4 mg/kg Se may ameliorate AFB1-induced apoptosis by increasing Bcl-2 mRNA expression, and decreasing Bax and Caspase-3 mRNA expression.

  1. La recherche-action participative facilite l'adaptation aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Application de la recherche-action participative à l'adaptation aux changements climatiques en Afrique : manuel de référence fait état des enseignements que les chercheurs ont tirés de leur expérience en recherche-action participative et fournit des renseignements utiles destinés aux chercheurs, aux responsables des ...

  2. Administration des subventions aux institutions Dépenses de projet ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    Consultants. Cette catégorie comprend toutes les dépenses engagées pour retenir les services d'un consultant aux ... déplacement, d'hébergement et de subsistance, ainsi qu'aux services de soutien retenus directement ... le transport aérien et les autres dépenses afférentes aux déplacements du personnel du projet à.

  3. Unusual carboxylesterase bearing a GGG(A)X-type oxyanion hole discovered in Paenibacillus barcinonensis BP-23.

    Science.gov (United States)

    Infanzón, Belén; Valenzuela, Susana V; Fillat, Amanda; Pastor, F I Javier; Diaz, Pilar

    2014-09-01

    Strain Paenibacillus barcinonensis BP-23, previously isolated from Ebro's river delta (Spain), bears a complex hydrolytic system showing the presence of at least two enzymes with activity on lipidic substrates. EstA, a cell-bound B-type carboxylesterase from the strain was previously isolated and characterized. The gene coding for a second putative lipase, located upstream cellulase Cel5A, was obtained using a genome walking strategy and cloned in Escherichia coli for further characterization. The recombinant clone obtained displayed high activity on medium/short-chain fatty acid-derivative substrates. The enzyme, named Est23, was purified and characterized, showing maximum activity on pNP-caprylate (C8:0) or MUF-heptanoate (C7:0) under conditions of moderate temperature and pH. Although Est23 displays a GGG(A)X-type oxyanion hole, described as an important motif for tertiary alcohol ester resolution, neither conversion nor enantiomeric resolution of tertiary alcohols could be detected. Amino acid sequence alignment of Est23 with those of known bacterial lipase families and with closely related proteins suggests that the cloned enzyme does not belong to any of the described bacterial lipase families. A phylogenetic tree including Est23 and similar amino acid sequences showed that the enzyme belongs to a differentiated sequence cluster which probably constitutes a new family of bacterial lipolytic enzymes. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  4. Pharmacokinetics and Toxicity of Sodium Selenite in the Treatment of Patients with Carcinoma in a Phase I Clinical Trial: The SECAR Study

    DEFF Research Database (Denmark)

    Brodin, Ola; Eksborg, Staffan; Wallenberg, Marita

    2015-01-01

    and the MTD of sodium selenite. The secondary endpoint was primary response evaluation. Results and Conclusion: MTD was defined as 10.2 mg/m(2), with a calculated median plasma half-life of 18.25 h. The maximum plasma concentration of selenium from a single dose of selenite increased in a nonlinear pattern...... current protocol. Further development of the study is underway to determine if prolonged infusions might be a more effective treatment strategy....

  5. Pharmacokinetics and Toxicity of Sodium Selenite in the Treatment of Patients with Carcinoma in a Phase I Clinical Trial: The SECAR Study

    Directory of Open Access Journals (Sweden)

    Ola Brodin

    2015-06-01

    Full Text Available Background: Sodium selenite at high dose exerts antitumor effects and increases efficacy of cytostatic drugs in multiple preclinical malignancy models. We assessed the safety and efficacy of intravenous administered sodium selenite in cancer patients’ refractory to cytostatic drugs in a phase I trial. Patients received first line of chemotherapy following selenite treatment to investigate altered sensitivity to these drugs and preliminary assessment of any clinical benefits. Materials and Methods: Thirty-four patients with different therapy resistant tumors received iv sodium selenite daily for consecutive five days either for two weeks or four weeks. Each cohort consisted of at least three patients who received the same daily dose of selenite throughout the whole treatment. If 0/3 patients had dose-limiting toxicities (DLTs, the study proceeded to the next dose-level. If 2/3 had DLT, the dose was considered too high and if 1/3 had DLT, three more patients were included. Dose-escalation continued until the maximum tolerated dose (MTD was reached. MTD was defined as the highest dose-level on which 0/3 or 1/6 patients experienced DLT. The primary endpoint was safety, dose-limiting toxic effects and the MTD of sodium selenite. The secondary endpoint was primary response evaluation. Results and Conclusion: MTD was defined as 10.2 mg/m2, with a calculated median plasma half-life of 18.25 h. The maximum plasma concentration of selenium from a single dose of selenite increased in a nonlinear pattern. The most common adverse events were fatigue, nausea, and cramps in fingers and legs. DLTs were acute, of short duration and reversible. Biomarkers for organ functions indicated no major systemic toxicity. In conclusion, sodium selenite is safe and tolerable when administered up to 10.2 mg/m2 under current protocol. Further development of the study is underway to determine if prolonged infusions might be a more effective treatment strategy.

  6. Tellurite-, tellurate-, and selenite-based anaerobic respiration by strain CM-3 isolated from gold mine tailings.

    Science.gov (United States)

    Maltman, Chris; Piercey-Normore, Michele D; Yurkov, Vladimir

    2015-09-01

    The newly discovered strain CM-3, a Gram-negative, rod-shaped bacterium from gold mine tailings of the Central Mine in Nopiming Provincial Park, Canada, is capable of dissimilatory anaerobic reduction of tellurite, tellurate, and selenite. CM-3 possesses very high level resistance to these oxides, both aerobically and anaerobically. During aerobic growth, tellurite and tellurate resistance was up to 1500 and 1000 µg/ml, respectively. In the presence of selenite, growth occurred at the highest concentration tested, 7000 µg/ml. Under anaerobic conditions, resistance was decreased to 800 µg/ml for the Te oxides; however, much like under aerobic conditions, growth with selenite still took place at 7000 µg/ml. In the absence of oxygen, CM-3 couples oxide reduction to an increase in biomass. Following an initial drop in viable cells, due to switching from aerobic to anaerobic conditions, there was an increase in CFU/ml greater than one order of magnitude in the presence of tellurite (6.6 × 10(3)-8.6 × 10(4) CFU/ml), tellurate (4.6 × 10(3)-1.4 × 10(5) CFU/ml), and selenite (2.7 × 10(5)-5.6 × 10(6) CFU/ml). A control culture without metalloid oxides showed a steady decrease in CFU/ml with no recovery. ATP production was also increased in the presence of each oxide, further indicating anaerobic respiration. Partial 16S rRNA gene sequencing revealed a 99.0 % similarity of CM-3 to Pseudomonas reactans.

  7. Molecular Structures of Al/Si and Fe/Si Coprecipitates and the Implication for Selenite Removal

    OpenAIRE

    Chan, Ya-Ting; Kuan, Wen-Hui; Tzou, Yu-Min; Chen, Tsan-Yao; Liu, Yu-Ting; Wang, Ming-Kuang; Teah, Heng-Yi

    2016-01-01

    Aluminum and iron oxides have been often used in the coagulation processes during water purification due to their unique surface properties toward anions. In the presence of silica, the coprecipitation of Al/Si or Fe/Si might decrease the efficiency of wastewater purification and reuse. In this study, surface properties and molecular structures of Al/Si and Fe/Si coprecipitates were characterized using spectroscopic techniques. Also, the selenite removal efficiency of Al/Si and Fe/Si coprecip...

  8. Detoxification of selenite and mercury by reduction and mutual protection in the assimilation of both elements by Pseudomonas fluorescens

    Energy Technology Data Exchange (ETDEWEB)

    Belzile, Nelson [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, P3E 2C6 (Canada)]. E-mail: nbelzile@laurentian.ca; Wu Gaojun [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, P3E 2C6 (Canada); Chen, Yu-Wei [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, P3E 2C6 (Canada); Appanna, Vasu D. [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, P3E 2C6 (Canada)

    2006-08-31

    A study on the assimilation and detoxification of selenium and mercury and on the interaction between these two elements was conducted on Pseudomonas fluorescens. P. fluorescens was able to convert separately both elements to their elemental forms, which are less toxic and biologically less available. To study the converting mechanism of selenite to elemental Se, cells were grown in the presence of various selenite concentrations and several parameters such as extracellular protein concentrations, pH, carbohydrate concentrations, isocitrate dehydrogenase (ICDH) and malic enzyme were monitored. Transmission electron microscopy (TEM) and various analytical methods were applied to confirm the interaction between selenium and cell. The former appeared as a red precipitate localized predominantly in the consumed culture medium. P. fluorescens also resisted to the toxic effect of mercury by converting Hg{sup 2+} to the volatile and less toxic form Hg . Mercury reductase was likely responsible for the conversion of Hg{sup 2+} to Hg . More importantly, the interaction between mercury and selenium was also studied. The presence of selenite significantly reduced the accumulation of mercury in P. fluorescens. It was also interesting to note that mercury appeared to behave as a protecting agent against selenium intoxication as the bioaccumulation of Se was also inhibited by this metal. The formation of Se-Hg complexes could explain this mutual protective effect. No precipitate of elemental Se could be detected when Hg was present in the cultures.

  9. Detoxification of selenite and mercury by reduction and mutual protection in the assimilation of both elements by Pseudomonas fluorescens

    International Nuclear Information System (INIS)

    Belzile, Nelson; Wu Gaojun; Chen, Yu-Wei; Appanna, Vasu D.

    2006-01-01

    A study on the assimilation and detoxification of selenium and mercury and on the interaction between these two elements was conducted on Pseudomonas fluorescens. P. fluorescens was able to convert separately both elements to their elemental forms, which are less toxic and biologically less available. To study the converting mechanism of selenite to elemental Se, cells were grown in the presence of various selenite concentrations and several parameters such as extracellular protein concentrations, pH, carbohydrate concentrations, isocitrate dehydrogenase (ICDH) and malic enzyme were monitored. Transmission electron microscopy (TEM) and various analytical methods were applied to confirm the interaction between selenium and cell. The former appeared as a red precipitate localized predominantly in the consumed culture medium. P. fluorescens also resisted to the toxic effect of mercury by converting Hg 2+ to the volatile and less toxic form Hg . Mercury reductase was likely responsible for the conversion of Hg 2+ to Hg . More importantly, the interaction between mercury and selenium was also studied. The presence of selenite significantly reduced the accumulation of mercury in P. fluorescens. It was also interesting to note that mercury appeared to behave as a protecting agent against selenium intoxication as the bioaccumulation of Se was also inhibited by this metal. The formation of Se-Hg complexes could explain this mutual protective effect. No precipitate of elemental Se could be detected when Hg was present in the cultures

  10. Sorption mechanisms of selenium species (selenite and selenate) on copper-based minerals; Mecanismes de sorption des especes du selenium (selenite et seleniate) sur des mineraux a base de cuivre

    Energy Technology Data Exchange (ETDEWEB)

    Devoy, J

    2001-09-01

    The sorption of radionuclides on the surface of minerals represents a process capable to delay the migration of the elements from a spent fuel deep repository towards the biosphere. In the framework of a deep underground repository, an engineered clay barrier has a high trapping capacity for cationic radio-elements, in particular because of the negative charge of clay surfaces. However, anionic radioelements like selenium species, would be only weakly retained by chemical processes. In order to optimize the trapping capacity of a clay barrier with respect to anionic species, prospective studies are carried out in order to find and evaluate some minerals with specific chemical trapping functions. Among radionuclides, the case of selenium has to be considered because its isotope {sup 79}Se is present in radioactive wastes and has a half life time of 6.5 10{sup 4} years. It is also judicious to find a mineral capable of trapping simultaneously several anionic radio-elements. Copper oxides and sulfides (Cu{sub 2}O, CuO, Cu{sub 2}S, CuS, CuFeS{sub 2} and Cu{sub 5}FeS{sub 4}) are good adsorbents with respect to selenium species (selenite and selenate). These minerals, with their selenium retention properties, could be used also for the decontamination of soils and waters or to process industrial effluents. The sorption mechanisms have been studied in details for copper oxides (Cu{sub 2}O and CuO) with respect to selenite and selenate. Chalcomenite precipitates in acid pH conditions when selenite is added to a Cu{sub 2}O and CuO suspension. Selenate, in contact with cuprite (Cu{sub 2}O) leads also to a selenium-based precipitate in acid pH environment. For higher pH values, selenite and selenate are adsorbed on copper oxides (Cu{sub 2}O and CuO) and lead to internal and external sphere complexes, respectively. In the case of a selenite/cuprite mixture in basic pH environment and at the equilibrium, a chemical reaction occurs between the oxidation product of cuprite, Cu

  11. Examen des Réactions D’intolérance aux Aliments et aux Additifs Alimentaires

    OpenAIRE

    Hayder, Hikmat; Mueller, Utz; Bartholomaeus, Andrew

    2011-01-01

    La communauté manifeste un intérêt soutenu à l’égard des réactions d’intolérance aux aliments et aux additifs alimentaires. Pour éclairer les discussions à ce sujet, l’agence FSANZ a entrepris un examen scientifique visant à approfondir les principaux enjeux qui sous‐ tendent le débat public. Le présent document fait état de la compréhension actuelle des intolérances alimentaires et met en évidence la variabilité des réactions d’intolérance selon les individus, de même...

  12. Thermodynamique des moteurs thermiques aux structures dissipatives

    CERN Document Server

    Prigogine, Ilya

    1999-01-01

    Ce livre constitue à la fois une présentation complète de la thermodynamique et une introduction scientifique à l'œuvre de Prigogine. Les auteurs innovent en montrant comment la thermodynamique du non-équilibre est un prolongement naturel de la thermodynamique de l'équilibre. Elle constitue ainsi la science des processus irréversibles - " la flèche du temps " - dont les structures dissipatives sont les témoignages les plus éclatants. Les développements historiques en font, non seulement un texte de référence, mais aussi un livre de culture. Les nombreux exemples et exercices, comme les programmes informatiques et les références aux sites Internet en font un outil de travail irremplaçable.

  13. Selenite -Se(4)- uptake mechanisms in the unicellular green alga Chlamydomonas reinhardtii: bioaccumulation and effects induced on growth and ultrastructure

    International Nuclear Information System (INIS)

    Morlon, H.

    2005-03-01

    Selenium is an essential element, but becomes very toxic at higher concentrations. It occurs in the environment at concentrations ranging from nM to μM and selenium pollution is a worldwide phenomenon. This works aims at improving the knowledge on the interactions between selenite - Se(IV) - and a freshwater phyto-planktonic organism: the unicellular green algae Chlamydomonas reinhardtii. The aim of the performed experiments were: i) to investigate selenite -Se(IV)- uptake mechanisms in C. reinhardtii, using Se 75 as a tracer in short term exposures ( -2 .nM -1 .h -1 . The uptake was proportional to ambient levels in a broad range of intermediate concentrations (from nM to μM). However, fluxes were higher at very low concentrations ( μM), suggesting that a high affinity but rapidly saturated transport mechanism could be used at low concentrations, in parallel with a low affinity mechanism that would only saturate at high concentrations (∼mM). The latter could involve transporters used by sulphate and nitrates, as suggested by the inhibition of selenite uptake by those element. Se(IV) speciation changes with pH did not induce significant effect on bioavailability. On the basis of the relationship between Se concentration and maximal cell density achieved, an EC50 of 80 μM ([64; 98]) was derived. No adaptation mechanism were observed as the same the same toxicity was quantified for Se-pre-exposed algae. Observations by TEM suggested chloroplasts as the first target of selenite cytotoxicity, with effects on the stroma, thylakoids and pyrenoids. At higher concentrations, we could observe an increase in the number and volume of starch grains. For the cell collected at 96 h, electron-dense granules were observed. Energy-dispersive X-ray microanalysis revealed that they contained selenium and were also rich in calcium and phosphorus. Finally, growth inhibition was highly correlated to the bioaccumulation of selenite. The latter was inhibited by increasing

  14. Investigating different mechanisms for biogenic selenite transformations: Geobacter sulfurreducens, Shewanella oneidensis and Veillonella atypica

    Science.gov (United States)

    Pearce, C.I.; Pattrick, R.A.D.; Law, N.; Charnock, J.M.; Coker, V.S.; Fellowes, J.W.; Oremland, R.S.; Lloyd, J.R.

    2009-01-01

    The metal-reducing bacteria Geobacter sulfurreducens, Shewanella oneidensis and Veillonella atypica, use different mechanisms to transform toxic, bioavailable sodium selenite to less toxic, non-mobile elemental selenium and then to selenide in anaerobic environments, offering the potential for in situ and ex situ bioremediation of contaminated soils, sediments, industrial effluents, and agricultural drainage waters. The products of these reductive transformations depend on both the organism involved and the reduction conditions employed, in terms of electron donor and exogenous extracellular redox mediator. The intermediary phase involves the precipitation of elemental selenium nanospheres and the potential role of proteins in the formation of these structures is discussed. The bionanomineral phases produced during these transformations, including both elemental selenium nanospheres and metal selenide nanoparticles, have catalytic, semiconducting and light-emitting properties, which may have unique applications in the realm of nanophotonics. This research offers the potential to combine remediation of contaminants with the development of environmentally friendly manufacturing pathways for novel bionanominerals. ?? 2009 Taylor & Francis.

  15. Switching to instant black coffee modulates sodium selenite-induced cataract in rats

    Directory of Open Access Journals (Sweden)

    El Okda, E. A.

    2016-04-01

    Full Text Available The influence of daily consumption of some common beverages on the development of cataract in rats was investigated. Total phenol content was determined in the beverages and an oral standardized dose of total phenols from each beverage was given to the treated rats. Weaned male albino rats were used and divided into five groups (n=7. Rats were fed Ain 93G and administered the standardized dose of instant coffee, black tea and hibiscus beverages for 30 days. On day 14 all rats were injected with a single dose of sodium selenite (NaSeO bodyweight, except the control groups NC (negative control, did not receive NaSeO and PC (positive control, was already injected on day 1 of the study. The rats were continued on Ain 93G and the standardized dose for another 16 days. Positive control rats were used. Total phenols were 210, 40, and 44 mg/g dry weight gallic acid equivalent in black coffee, black tea, and hibiscus, respectively. Decreased levels (statistically significant P<0.05 of malondialdehyde, total nitric oxide, Ca-Ae, tumor necrosis factor-α, interleukin-1β, superoxide dismutase, and conversely, increased levels (statistically significant P<0.05 of total protein, reduced glutathione, catalase were found in the lenses of the coffee group compared to PC. There are co-phenol substances in the instant black coffee that promoted coffee to be the most effective beverage.

  16. Radioprotective effect of sodium selenite on bone repair in the tibia of ovariectomized rats

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Deborah Queiroz de; Neves, Ellen Gaby; Boscolo, Frab Norberto; Almeida, Solange Maria de [University of Campinas (UNICAMP), Piracicaba, SP (Brazil). Piracicaba Dental School. Department of Oral Diagnosis. Oral Radiology Area; Ramos-Perez, Flavia Maria de Moraes [Federal University of Pernambuco, Recife, PE (Brazil). Department of Clinical and Preventive Dentistry; Marques, Marcelo Rocha [University of Campinas (UNICAMP), Piracicaba, SP (Brazil). Piracicaba Dental School. Division of Histology. Department of Morphology

    2012-07-01

    This study evaluated protection by selenium (Se) in the bone repair process in ovariectomized rats after irradiation. For such purpose, 80 ovariectomized female Wistar rats were randomly divided into 4 experimental groups: ovariectomized (Ov), Ov/Se, Ov/irradiated (Irr) and Ov/ Se/Irr. A bone defect was created on the tibia of all animals 40 days after ovariectomy. Two days after surgery, only the Ov/Se and Ov/Se/Irr rats received 0.8 mg Se/kg. Three days after surgery, only the Ov/Irr and Ov/Se/Irr rats received 10 Gy of x-rays on the lower limb region. The animals were euthanized at 7, 14, 21 and 28 days after surgery to assess the repair process, which was evaluated by analysis of trabecular bone number (Masson Trichrome) and birefringence analysis (Picrosirius). It was possible to observe a delay in the bone repair process in the ovariectomized/irradiated group and similarity between the ovariectomized, Ov/Se and Ov/Se/Irr groups. In conclusion, sodium selenite exerted a radioprotective effect in the bone repair of tibia of ovariectomized rats without toxicity. (author)

  17. Application of Sodium Selenite in the Prevention and Treatment of Cancers

    Directory of Open Access Journals (Sweden)

    Marek Kieliszek

    2017-10-01

    Full Text Available Selenium is an essential trace element that occurs in nature, in both inorganic and organic forms. This element participates in numerous biochemical processes, including antioxidant potential, but the mechanism of its anti-cancer action is still not well known. It should be noted that the anti-cancer properties of selenium depends on its chemical form, therapeutic doses, and the tumor type. Higher nutritional doses of selenium can stimulate human immune system. There are several hypotheses concerning the anticancer activity of selenium, including oxidation of sulfhydryl groups in proteins causing their conformational alterations. Conformational changes in proteins have the ability to weaken the activity of enzymes involved in the metabolism of cancer cells. In case of human fibrinogen sodium selenite, but not selenate, it inhibits protein disulfide exchange reactions, thus preventing formation of a hydrophobic polymer termed parafibrin, circulatory accumulation, of which is associated with numerous degenerative diseases. Parafibrin can specifically form a protein coat around tumor cells that is completely resistant to degradation induced with lymphocyte protease. In this way, cancer cells become protected against destruction by the organism’s immune system. Other possible mechanisms of anticancer action of selenium are being still investigated.

  18. Synthesis, structure, and photoluminescence properties of an organically-templated uranyl selenite

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dong-Sheng; Kuang, Han-Mao; Chen, Wen-Tong; Luo, Qiu-Yan; Sui, Yan [Institute of Applied Chemistry, School of Chemistry and Chemical Engineering, Jinggangshan University, Ji' an, Jiangxi 343009 (China)

    2015-09-15

    The organically-templated uranyl selenite, (H{sub 2}en)[(UO{sub 2})(SeO{sub 3})(HSeO{sub 3})](NO{sub 3}).0.5H{sub 2}O (1) (en = 1,2-ethylenediamine) was synthesized and characterized by elemental analyses, IR spectroscopy, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic system, space group Pbca, with a = 13.170(3) Aa, b = 11.055(2) Aa, c = 18.009(4) Aa, V = 2621.8(9) Aa{sup 3}, M = 1316.19, Z = 4, D{sub cal} = 3.334 g.cm{sup -3}, μ(Mo-K{sub α}) = 17.998 mm{sup -1}, GOF = 1.059, R{sub 1} = 0.0263, wR{sub 2} = 0.0532 [I>2σ(I)]. The X-ray diffraction analysis reveals that compound 1 has a three-dimensional (3D) supramolecular structure. It contains negatively charged [UO{sub 2}(HSeO{sub 3})(SeO{sub 3})]{sup -} inorganic anion layers and is balanced by [H{sub 2}en]{sup 2+} cations and NO{sub 3}{sup -} anions located in the interlayers. Furthermore, the photoluminescence properties of 1 were investigated. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Synthesis, structure, and photoluminescence properties of an organically-templated uranyl selenite

    International Nuclear Information System (INIS)

    Liu, Dong-Sheng; Kuang, Han-Mao; Chen, Wen-Tong; Luo, Qiu-Yan; Sui, Yan

    2015-01-01

    The organically-templated uranyl selenite, (H 2 en)[(UO 2 )(SeO 3 )(HSeO 3 )](NO 3 ).0.5H 2 O (1) (en = 1,2-ethylenediamine) was synthesized and characterized by elemental analyses, IR spectroscopy, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic system, space group Pbca, with a = 13.170(3) Aa, b = 11.055(2) Aa, c = 18.009(4) Aa, V = 2621.8(9) Aa 3 , M = 1316.19, Z = 4, D cal = 3.334 g.cm -3 , μ(Mo-K α ) = 17.998 mm -1 , GOF = 1.059, R 1 = 0.0263, wR 2 = 0.0532 [I>2σ(I)]. The X-ray diffraction analysis reveals that compound 1 has a three-dimensional (3D) supramolecular structure. It contains negatively charged [UO 2 (HSeO 3 )(SeO 3 )] - inorganic anion layers and is balanced by [H 2 en] 2+ cations and NO 3 - anions located in the interlayers. Furthermore, the photoluminescence properties of 1 were investigated. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Sorption of selenite (SeO{sub 3}{sup 2{minus}}) on hydroxyapatite: An exchange process

    Energy Technology Data Exchange (ETDEWEB)

    Monteil-Rivera, F.; Fedoroff, M.; Jeanjean, J.; Minel, L.; Barthes, M.G.; Dumonceau, J.

    2000-01-15

    The sorption of SeO{sub 3}{sup 2{minus}} on hydroxyapatite surface was investigated in batch experiments over a range of pH and SeO{sub 3}{sup 2{minus}} concentrations in the absence and presence of additional Ca and PO{sub 4}. The sorption is pH dependent with a maximum observed at pH values generally encountered in natural waters. While the presence of phosphate lowers SeO{sub 3}{sup 2{minus}} sorption by direct competition, the presence of calcium enhances it. In order to identify the mechanism of sorption and the nature of the surface sites, microscopic observation and spectroscopic methods such as X-ray diffraction and X-ray photoelectron spectroscopy were used. Surface complexation, coprecipitation, and precipitation processes were ruled out. Localization of sorbed selenium in the crystallographic sites where phosphorus is normally located shows that selenite is sorbed on the apatite by an anionic exchange with phosphate groups. Although the exact equilibria involved could not be established, the stoichiometry of the exchange is close to 1:1. According to kinetics experiments and X-ray diffraction analyses, it seems that selenium is not exclusively located at the surface but diffuses slightly in a thickness of a few nanometers.

  1. Mechanism(s of Toxic Action of Zn2+ and Selenite: A Study on AS-30D Hepatoma Cells and Isolated Mitochondria

    Directory of Open Access Journals (Sweden)

    Elena A. Belyaeva

    2011-01-01

    Full Text Available Mitochondria of AS-30D rat ascites hepatoma cells are found to be the main target for Zn2+ and sodium selenite (Na2SeO3. High [mu]M concentrations of Zn2+ or selenite were strongly cytotoxic, killing the AS-30D cells by both apoptotic and necrotic ways. Both Zn2+ and selenite produced strong changes in intracellular generation of reactive oxygen species (ROS and the mitochondrial dysfunction via the mitochondrial electron transport chain (mtETC disturbance, the membrane potential dissipation, and the mitochondrial permeability transition pore opening. The significant distinctions in toxic action of Zn2+ and selenite on AS-30D cells were found. Selenite induced a much higher intracellular ROS level (the early event compared to Zn2+ but a lower membrane potential loss and a lower decrease of the uncoupled respiration rate of the cells, whereas the mtETC disturbance was the early and critical event in the mechanism of Zn2+ cytotoxicity. Sequences of events manifested in the mitochondrial dysfunction produced by the metal/metalloid under test are compared with those obtained earlier for Cd2+, Hg2+, and Cu2+ on the same model system.

  2. Effects of lead nitrate and sodium selenite on DNA damage and oxidative stress in diabetic and non-diabetic rat erythrocytes and leucocytes.

    Science.gov (United States)

    Baş, Hatice; Kalender, Yusuf; Pandir, Dilek; Kalender, Suna

    2015-05-01

    The adverse effects of lead nitrate (LN) and the preventive role of sodium selenite were investigated in diabetic and non-diabetic rat blood by measuring trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP), malondialdehyde (MDA) levels and activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) also by evaluating DNA damage with comet assay. LN increased the levels of MDA, tail DNA%, mean tail length and tail moment, decreased the enzymes activities, FRAP and TEAC values. In sodium selenite+LN group, we observed the protective effect of sodium selenite on examining parameters. Diabetes caused alterations on these parameters, too. We found that sodium selenite did not protect against diabetes caused damages. As a result, LN caused toxic effects on blood cells and sodium selenite alleviated this toxicity but it did not show preventive effect against diabetes. Also, LN caused more harmfull effects in diabetic groups than non-diabetic groups. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Improving enantioselectivity towards tertiary alcohols using mutants of Bacillus sp. BP-7 esterase EstBP7 holding a rare GGG(X)-oxyanion hole.

    Science.gov (United States)

    Fillat, Amanda; Romea, Pedro; Urpí, Fèlix; Pastor, F I Javier; Diaz, Pilar

    2014-05-01

    Lipases and esterases are important biocatalysts for synthetic organic fine chemistry. An esterase from Bacillus sp. BP-7 (EstBP7) bears in its amino acid sequence a rare GGG(A)X oxyanion hole motif, where an uncommon threonine (T) is found at the third position. Detection of this pattern motivated evaluation of the ability of EstBP7 for conversion of tertiary alcohols. The enzyme was engineered in order to optimize its performance to provide important chiral building blocks: five variants with mutations in the oxyanion hole motif were created to investigate the influence on activity and enantioselectivity in the kinetic resolution of eight acetates of tertiary alcohols. Wild-type enzyme converted all esters of tertiary alcohols assayed with low enantioselectivity, whereas some of the mutants displayed significantly increased E-values. One of the mutants (EstBP7-AGA; Mut 5) showed an E >100 towards a complex tertiary alcohol acetate (2-(4-pyridyl)but-3-yn-2-yl acetate) at low reaction temperature (4 °C). Therefore, the catalytic toolbox was expanded for biocatalysis of optically pure tertiary alcohols valuable for the pharmaceutical industry.

  4. Engineering metal (hydr)oxide sorbents for removal of arsenate and similar weak-acid oxyanion contaminants: A critical review with emphasis on factors governing sorption processes.

    Science.gov (United States)

    Hristovski, Kiril D; Markovski, Jasmina

    2017-11-15

    To create an integrative foundation for engineering of the next generation inexpensive sorbent systems, this critical review addresses the existing knowledge gap in factor/performance relationships between weak-acid oxyanion contaminants and metal (hydr)oxide sorbents. In-depth understanding of fundamental thermodynamics and kinetics mechanisms, material fabrication, and analytical and characterization techniques, is necessary to engineer sorbent that exhibit high capacity, selectivity, stability, durability and mass transport of contaminants under a wide range of operating and water matrix conditions requirements. From the perspective of thermodynamics and kinetics, this critical review examines the factors affecting sorbent performances and analyzes the existing research to elucidate future directions aimed at developing novel sorbents for removal of weak-acid oxyanion contaminants from water. Only sorbents that allow construction of simple and inexpensive water treatment systems adapted to overcome fiscal and technological barriers burdening small communities could pave the road for providing inexpensive potable water to millions of people. Novel sorbents, which exhibit (1) poor performances in realistic operating and water matrix conditions and/or (2) do not comply with the purely driven economics factors of production scalability or cost expectations, are predestined to never be commercialized. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Ligand size is a major determinant of specificity in periplasmic oxyanion-binding proteins: the 1.2 A resolution crystal structure of Azotobacter vinelandii ModA.

    Science.gov (United States)

    Lawson, D M; Williams, C E; Mitchenall, L A; Pau, R N

    1998-12-15

    . Periplasmic receptors constitute a diverse class of binding proteins that differ widely in size, sequence and ligand specificity. Nevertheless, almost all of them display a common beta/alpha folding motif and have similar tertiary structures consisting of two globular domains. The ligand is bound at the bottom of a deep cleft, which lies at the interface between these two domains. The oxyanion-binding proteins are notable in that they can discriminate between very similar ligands. . Azotobacter vinelandii is unusual in that it possesses two periplasmic molybdate-binding proteins. The crystal structure of one of these with bound ligand has been determined at 1.2 A resolution. It superficially resembles the structure of sulphate-binding protein (SBP) from Salmonella typhimurium and uses a similar constellation of hydrogen-bonding interactions to bind its ligand. However, the detailed interactions are distinct from those of SBP and the more closely related molybdate-binding protein of Escherichia coli. . Despite differences in the residues involved in binding, the volumes of the binding pockets in the A. vinelandii and E. coli molybdate-binding proteins are similar and are significantly larger than that of SBP. We conclude that the discrimination between molybdate and sulphate shown by these binding proteins is largely dependent upon small differences in the sizes of these two oxyanions.

  6. Adsorption of arsenite and selenite using an inorganic ion exchanger based on Fe–Mn hydrous oxide

    KAUST Repository

    Szlachta, Małgorzata

    2012-01-01

    The adsorption behaviour and mechanism of As(III) and Se(IV) oxyanion uptake using a mixed inorganic adsorbent were studied. The novel adsorbent, based on Fe(III)-Mn(III) hydrous oxides and manganese(II) carbonate, was synthesised using a hydrothermal precipitation approach in the presence of urea. The inorganic ion exchanger exhibited a high selectivity and adsorptive capacity towards As(III) (up to 47.6mg/g) and Se(IV) (up to 29.0mg/g), even at low equilibrium concentration. Although pH effects were typical for anionic species (i.e., the adsorption decreased upon pH increase), Se(IV) was more sensitive to pH changes than As(III). The rates of adsorption of both oxyanions were high. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) studies showed that the ion exchange adsorption of both anions took place via OH - groups, mainly from Fe(III) but also Mn(III) hydrous oxides. MnCO 3 did not contribute directly to As(III) and Se(IV) removal. A higher adsorptive capacity of the developed material towards As(III) was partly due to partial As(III) oxidation during adsorption. © 2011 Elsevier Inc.

  7. Effect of sodium selenite on thyroid gland functioning and efficacy of chemotherapy in tuberculosis patients with a concomitant diabetes mellitus and autoimmune thyroiditis

    Directory of Open Access Journals (Sweden)

    S.L. Matveyeva

    2017-10-01

    Full Text Available In 40 tuberculosis patients with diabetes mellitus and autoimmune thyroiditis ultrasonic research of thyroid structure and measurement of levels of free thyroxine, thyroid stimulating hormone, antibodies to thyroglobulin and peroxidase and selenium in the serum of blood were conducted by immune-enzyme method at the beginning and at the end of the phase of intensive chemotherapy depending on the prescribing of sodium selenite. Efficacy of antituberculosis chemotherapy was estimated by general clinical, bacteriological and X-ray criteria. Autoimmune thyroiditis with the phenomena of subclinical hypothyroidism is diagnosed for all investigational persons. Prescribing of sodium selenite during the phase of intensive chemotherapy promotes the recovery of thyroid function. Rates of intoxication symptoms elimination, abacillation reduction and healing of the cavities at the end of intensive phase of chemotherapy were for certain higher in the group of patients with prescribing of sodium selenite.

  8. Communications en cas de catastrophe faisant appel aux TIC pour ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Communications en cas de catastrophe faisant appel aux TIC pour les collectivités vulnérables des Caraïbes. De récents événements survenus dans les Caraïbes ont mis en relief les insuffisances des mesures régionales et nationales de préparation aux catastrophes. On manque particulièrement de systèmes d'alerte ...

  9. Donner aux travailleurs du sexe les moyens de consigner les ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Dans la plupart des sociétés, le travail du sexe est fortement stigmatisé, et ceux qui le pratiquent sont en butte aux reproches, à la désapprobation et à la discrimination. Par conséquent, la violence faite aux travailleurs du sexe se voit peu, et dans certains contextes, elle est même tolérée. On dispose donc de très peu de ...

  10. Resistance aux antibiotiques des bacteries isolees en 2009 au ...

    African Journals Online (AJOL)

    Objectif : Contribuer à la surveillance de la résistance bactérienne aux antibiotiques au Togo en étudiant la résistance aux antibiotiques des bactéries. Méthode Il s'agit d'une étude descriptive transversale portant sur les comptes rendus des antibiogrammes réalisés du 1er janvier au 31 décembre 2009 au Laboratoire de ...

  11. Donner la parole aux femmes - bourse de recherche sur la ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    16 mai 2016 ... Donner la parole aux femmes - bourse de recherche sur la militarisation et les femmes en Asie du Sud destinée aux journalistes. L'Asie du Sud est la région la plus densément peuplée du monde et, selon les indicateurs de pauvreté, la deuxième plus pauvre, après l'Afrique subsaharienne. Il s'agit ...

  12. Bourse du CRDI aux chercheurs candidats au doctorat 2017 | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Avant de faire une demande, veuillez lire les documents suivants : Liste de vérification des documents que doit remettre le candidat · Foire aux questions générales · Foire aux questions techniques en cas de difficultés d'ordre technique au moment de remplir la demande en ligne; Lettre type d'approbation du directeur de ...

  13. Fabrication and physicochemical characterization of porous composite microgranules with selenium oxyanions and risedronate sodium for potential applications in bone tumors

    Directory of Open Access Journals (Sweden)

    Kolmas J

    2017-08-01

    Full Text Available Joanna Kolmas,1 Kamil Pajor,1 Lukasz Pajchel,1 Agata Przekora,2 Grażyna Ginalska,2 Ewa Oledzka,3 Marcin Sobczak3 1Department of Inorganic and Analytical Chemistry, Faculty of Pharmacy with Laboratory Medicine Division, Medical University of Warsaw, Warsaw, 2Department of Biochemistry and Biotechnology, Faculty of Pharmacy with Medical Analytics Division, Medical University of Lublin, Lublin, 3Department of Biomaterials Chemistry, Faculty of Pharmacy with Laboratory Medicine Division, Medical University of Warsaw, Warsaw, Poland Abstract: Nanocrystalline hydroxyapatite containing selenite ions (SeHA; 9.6 wt.% of selenium was synthesized using wet method and subject to careful physicochemical analysis by powder X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, solid-state nuclear magnetic resonance, wavelength dispersive X-ray fluorescence, and inductively coupled plasma optical emission spectrometry. SeHA was then used to develop the selenium-containing hydroxyapatite/alginate (SeHA/ALG composite granules. Risedronate sodium (RIS was introduced to the obtained spherical microgranules of a size of about 1.1–1.5 mm in 2 ways: during the granules’ preparation (RIS solution added to a suspension of ALG and SeHA, and as a result of SeHA/ALG granules soaking in aqueous RIS solution. The analysis made using 13C and 31P cross-polarization magic angle spinning nuclear magnetic resonance confirmed the presence of RIS and its interaction with calcium ions. Then, the release of selenium (inductively coupled plasma optical emission spectrometry and RIS (high-performance liquid chromatography from microgranules was examined. Moreover, cytotoxicity of fabricated granules was assessed by MTT test. Selenium release was biphasic: the first stage was short and ascribed to a “burst release” probably from a hydrated surface layer of SeHA crystals, while the next stage was significantly longer and ascribed to a

  14. Favreauite, a new selenite mineral from the El Dragon mine, Bolivia

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Stuart J. [Museum Victoria, Melbourne, VIC (Australia). Geosciences; Kampf, Anthony R. [Natural History Museum of Los Angeles, CA (United States). Mineral Sciences Dept.; Christy, Andrew G. [Australian National Univ., Canberra, ACT (Australia). Centre for Advanced Microscopy; Housley, Robert M. [California Institute of Technology, Pasadena, CA (United States). Div. of Geological and Planetary Sciences; Chen, Yu-Sheng [Chicago Univ., IL (United States). Center for Advanced Radiation Sources; Steele, Ian M. [Chicago Univ., IL (United States). Center for Advanced Radiation Sources; Thorne, Brent

    2014-07-01

    Favreauite, ideally PbBiCu{sub 6}O{sub 4}(SeO{sub 3}){sub 4}.H{sub 2}O, is a new secondary selenite mineral from the El Dragon mine, Antonio Quijarro Province, Potosi Department, Bolivia. The mineral occurs in vughs in a matrix of (Co, Cu)-rich penroseite, dolomite and goethite. Associated minerals are: ahlfeldite, allophane, calcite, chalcomenite, malachite, molybdomenite and an unnamed Al selenite. Favreauite forms tiny green square tbular crystals, flattened on {001}, up to 0.1 mm on edge and 0.01 mm thick, occurring in subparallel and divergent groups. The Mohs hardness of favreauite is estimated as ∼3; it has perfect cleavage on {001}, an irregular fracture and a vitreous lustre. The calculated density based on the empirical formula is 4.851 g cm{sup -3}. Favreauite is uniaxial (-), with mean refractive index estimated as 1.854 from the Gladstone-Dale relationship. It is pleochroic in shades of green, O < E. Electron microprobe analyses gave the empirical formula Pb{sub 0.95}Ca{sub 0.17}Bi{sub 0.90}Cu{sub 5.81}Se{sub 4.10}O{sub 16}(OH) . 1H{sub 2}O, based on 18 O pfu. The Raman spectrum shows strong SeO{sub 3} bands at 847 cm{sup -1} (ν{sub 1}), 764 and 795 cm{sup -1} (ν{sub 3}), 493 and 542 cm{sup -1} (ν{sub 2}), and 320 and 392 cm{sup -1} (ν{sub 4}). Favreauite is tetragonal, space group P4/n, with the unit-cell parameters: a = 9.860(4) Aa, c = 9.700(5) Aa, V = 943.0(9) Aa{sup 3} and Z = 2. The eight strongest lines in the X-ray powder diffraction pattern are [d{sub obs}/Aa (I) (hkl)]: 5.67(100)(111), 3.470(76)(220,202), 3.190(35)(003), 2.961(40)(311,113), 2.709(33)(302,203), 2.632(34)(231,312), 2.247(36)(331,133), and 1.6652(33)(305,513,531). The crystal structure was refined to R{sub 1} = 0.0329 for 1354 observed reflections [F{sub o} > 4σF{sub o}] and 0.0356 for all 1432 unique reflections. Favreauite is a close structural relative of nabokoite, KCu{sub 7}Te{sup 4+}O{sub 4}(SO{sub 4}){sub 5}Cl, and atlasovite, KCu{sub 6}Fe{sup 3+}BiO{sub 4}(SO

  15. Field study of time-dependent selenium partitioning in soils using isotopically enriched stable selenite tracer

    Energy Technology Data Exchange (ETDEWEB)

    Di Tullo, Pamela, E-mail: pamela.ditullo@univ-pau.fr [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement (LCABIE), Université de Pau et des Pays de l' Adour/CNRS, UMR 5254, IPREM, Hélioparc, 2 Avenue du Président Angot, 64053 Pau Cedex 9 (France); Andra, Research and Development Division, Parc de la Croix Blanche, 1-7 rue Jean Monnet, 92298 Châtenay-Malabry Cedex (France); Pannier, Florence, E-mail: florence.pannier@univ-pau.fr [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement (LCABIE), Université de Pau et des Pays de l' Adour/CNRS, UMR 5254, IPREM, Hélioparc, 2 Avenue du Président Angot, 64053 Pau Cedex 9 (France); Thiry, Yves, E-mail: yves.thiry@andra.fr [Andra, Research and Development Division, Parc de la Croix Blanche, 1-7 rue Jean Monnet, 92298 Châtenay-Malabry Cedex (France); Le Hécho, Isabelle, E-mail: isabelle.lehecho@univ-pau.fr [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement (LCABIE), Université de Pau et des Pays de l' Adour/CNRS, UMR 5254, IPREM, Hélioparc, 2 Avenue du Président Angot, 64053 Pau Cedex 9 (France); Bueno, Maïté, E-mail: maite.bueno@univ-pau.fr [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement (LCABIE), Université de Pau et des Pays de l' Adour/CNRS, UMR 5254, IPREM, Hélioparc, 2 Avenue du Président Angot, 64053 Pau Cedex 9 (France)

    2016-08-15

    A better understanding of selenium fate in soils at both short and long time scales is mandatory to consolidate risk assessment models relevant for managing both contamination and soil fertilization issues. The purpose of this study was thus to investigate Se retention processes and their kinetics by monitoring time-dependent distribution/speciation changes of both ambient and freshly added Se, in the form of stable enriched selenite-77, over a 2-years field experiment. This study clearly illustrates the complex reactivity of selenium in soil considering three methodologically defined fractions (i.e. soluble, exchangeable, organic). Time-dependent redistribution of Se-77 within solid-phases having different reactivity could be described as a combination of chemical and diffusion controlled processes leading to its stronger retention. Experimental data and their kinetic modeling evidenced that transfer towards less labile bearing phases are controlled by slow processes limiting the overall sorption of Se in soils. These results were used to estimate time needed for {sup 77}Se to reach the distribution of naturally present selenium which may extend up to several decades. Ambient Se speciation accounted for 60% to 100% of unidentified species as function of soil type whereas {sup 77}Se(IV) remained the more abundant species after 2-years field experiment. Modeling Se in the long-term without taking account these slow sorption kinetics would thus result in underestimation of Se retention. When using models based on K{sub d} distribution coefficient, they should be at least reliant on ambient Se which is supposed to be at equilibrium.

  16. Syntheses and structures of three f-element selenite/hydroselenite compounds

    International Nuclear Information System (INIS)

    Burns, Wendy L.; Ibers, James A.

    2009-01-01

    The selenite/hydroselenite compounds Ce(SeO 3 )(HSeO 3 ), Tb(SeO 3 )(HSeO 3 ).2H 2 O, and Cs[U(SeO 3 )(HSeO 3 )].3H 2 O were synthesized by hydrothermal means at 453 K from the reaction of CeO 2 or Tb 4 O 7 or UO 2 with SeO 2 and CsCl (as a mineralizer). Ce(SeO 3 )(HSeO 3 ) crystallizes in the non-centrosymmetric orthorhombic space group Pca2 1 . The structure comprises a two-dimensional network of interconnected CeO 10 bicapped distorted square antiprisms and SeO 3 trigonal pyramids. Tb(SeO 3 )(HSeO 3 ).2H 2 O crystallizes in the non-centrosymmetric orthorhombic space group P2 1 2 1 2 1 . The structure features a two-dimensional layer of interconnected TbO 8 distorted square antiprisms and SeO 3 trigonal pyramids. Cs[U(SeO 3 )(HSeO 3 )].3H 2 O crystallizes in the centrosymmetric monoclinic space group P2 1 /n. The structure consists of two-dimensional layers of interconnected UO 7 pentagonal bipyramids and SeO 3 trigonal pyramids. The layers in all three structures are held together by hydrogen-bonding networks. - Graphical abstract: Structure of Ce[U(SeO 3 )(HSeO 3 )].3H 2 O (Cs, purple; U, black; Se, blue; O, red; O w , green; H, gray).

  17. Tissue concentration-time profile of selenium after sodium selenite administration to rats

    International Nuclear Information System (INIS)

    Kaneko, Megumi; Natsuhori, Masahiro; Ito, Nobuhiko; Sera, Koichiro; Futatsugawa, Shoji

    1999-01-01

    Selenium (Se) concentration-time profiles in plasma and organs including liver, kidney, heart, lung, spleen and brain of rats (Jcl Wister, 9 wks old, n=32) were investigated after a single intravenous (iv) / oral (po) administration of sodium selenite (dose is equivalent to 2 mg/kg b.w. of Se). The Se concentration was determined by PIXE analysis. Among the investigated biological samples, Se concentration was the highest in the kidney or liver, followed by the heart, lung or spleen, then plasma, and the brain. Se concentrations in these organs were 0.5 to 5 times of plasma Se. The distribution profiles of Se in the organs were dependent on the route of administration. Furthermore, their profiles appeared almost parallel to the plasma Se-concentration in a logarithmic scale. Compared to the Se concentration-time profiles in plasma and organs by the route of administration, po group showed about 1/4-1/2 of the Se concentration in iv group except for kidney. Kidney kept relatively higher concentration of Se, which was similar in the both groups. This may explain our recently published data that urinary excretion was similar in the both groups. The relative oral bioavailability of plasma and each organ was calculated by the ratio of area under the concentration-time curve after oral administration (AUCpo) to AUCiv. Each organ appeared to have their own bioavailability (i.e., liver 39%, kidney 97%, heart 37%, lung 18%, spleen 10%, and brain 72%), where plasma was 46%. These results highly suggested that different Se distribution in organs by the different route of administration was due to the different metabolic profile. (author)

  18. Effects of 14-day oral low dose selenium nanoparticles and selenite in rat—as determined by metabolite pattern determination

    DEFF Research Database (Denmark)

    Hadrup, Niels; Löschner, Katrin; Skov, Kasper

    2016-01-01

    toxic effects may occur. We used metabolite pattern determination in urine to investigate biological and/or toxic effects in rats administered nanoparticles and for comparison included ionic selenium at an equimolar dose in the form of sodium selenite. Low doses of 10 and 100 fold the recommended human......Selenium (Se) is an essential element with a small difference between physiological and toxic doses. To provide more effective and safe Se dosing regimens, as compared to dosing with ionic selenium, nanoparticle formulations have been developed. However, due to the nano-formulation, unexpected...

  19. Participation du secteur de la sécurité privé aux conflits et aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Participation du secteur de la sécurité privé aux conflits et aux opérations de maintien de la paix et d'assistance humanitaire en Afrique. En 2006, l'Institute for Security Studies (ISS) a entrepris un projet portant sur la réglementation du secteur de la sécurité privé en Afrique, financé par le CRDI dans le cadre du projet no ...

  20. Differential protein expression of Caco-2 cells treated with selenium nanoparticles compared with sodium selenite and selenomethionine

    Science.gov (United States)

    Fu, Linglin; Yan, Xuxia; Ruan, Xinming; Lin, Junda; Wang, Yanbo

    2014-10-01

    The study was designed to determine the differential protein expression of Caco-2 cells treated with different forms of selenium including sodium selenite, selenomethionine (Se-Met), and selenium nanoparticles (nano-Se). Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry (MS) were used to identify the differentially expressed proteins. The results indicated that seven protein spots, ubiquitin-conjugating enzyme E2 (E2), glutathione synthetases (GS), triosephosphate isomerase (TSP), T-complex protein 1 subunit zeta (TCPZ), lamin-B1, heterogeneous nuclear ribonucleoprotein F (hnRNP F), and superoxide dismutase [Cu-Zn] (Cu, Zn-SOD) were significantly different among all the groups. According to the order of control, sodium selenite, Se-Met, and Nano-Se, the expression levels of two proteins (E2 and GS) increased and the other differential proteins were reverse. Except for E2, there were no significant differences in other protein expressions between the groups treated with nano-Se and Se-Met.

  1. Molecular Structures of Al/Si and Fe/Si Coprecipitates and the Implication for Selenite Removal.

    Science.gov (United States)

    Chan, Ya-Ting; Kuan, Wen-Hui; Tzou, Yu-Min; Chen, Tsan-Yao; Liu, Yu-Ting; Wang, Ming-Kuang; Teah, Heng-Yi

    2016-04-20

    Aluminum and iron oxides have been often used in the coagulation processes during water purification due to their unique surface properties toward anions. In the presence of silica, the coprecipitation of Al/Si or Fe/Si might decrease the efficiency of wastewater purification and reuse. In this study, surface properties and molecular structures of Al/Si and Fe/Si coprecipitates were characterized using spectroscopic techniques. Also, the selenite removal efficiency of Al/Si and Fe/Si coprecipitates in relation to their surface and structural properties was investigated. While dissolved silicate increased with increasing pH from Fe/Si coprecipitates, less than 7% of silicate was discernible from Al/Si samples over the range from acidic to alkaline conditions. Our spectroscopic results showed that the associations between Al and Si were relatively stronger than that between Fe and Si in coprecipitates. In Al/Si coprecipitates, core-shell structures were developed with AlO6/AlO4 domains as the shells and Si frameworks polymerized from the SiO2 as the cores. However, Si framework remained relatively unchanged upon coprecipitation with Fe hydroxides in Fe/Si samples. The Si core with Al shell structure of Al/Si coprecipitates shielded the negative charges from SiO2 and thereby resulted in a higher adsorption capacity of selenite than Fe/Si coprecipitates.

  2. Palladium nanoparticles encapsulated in core-shell silica: A structured hydrogenation catalyst with enhanced activity for reduction of oxyanion water pollutants

    KAUST Repository

    Wang, Yin

    2014-10-03

    Noble metal nanoparticles have been applied to mediate catalytic removal of toxic oxyanions and halogenated hydrocarbons in contaminated water using H2 as a clean and sustainable reductant. However, activity loss by nanoparticle aggregation and difficulty of nanoparticle recovery are two major challenges to widespread technology adoption. Herein, we report the synthesis of a core-shell-structured catalyst with encapsulated Pd nanoparticles and its enhanced catalytic activity in reduction of bromate (BrO3-), a regulated carcinogenic oxyanion produced during drinking water disinfection process, using 1 atm H2 at room temperature. The catalyst material consists of a nonporous silica core decorated with preformed octahedral Pd nanoparticles that were further encapsulated within an ordered mesoporous silica shell (i.e., SiO2@Pd@mSiO2). Well-defined mesopores (2.3 nm) provide a physical barrier to prevent Pd nanoparticle (6 nm) movement, aggregation, and detachment from the support into water. Compared to freely suspended Pd nanoparticles and SiO2@Pd, encapsulation in the mesoporous silica shell significantly enhanced Pd catalytic activity (by a factor of 10) under circumneutral pH conditions that are most relevant to water purification applications. Mechanistic investigation of material surface properties combined with Langmuir-Hinshelwood modeling of kinetic data suggest that mesoporous silica shell enhances activity by promoting BrO3- adsorption near the Pd active sites. The dual function of the mesoporous shell, enhancing Pd catalyst activity and preventing aggregation of active nanoparticles, suggests a promising general strategy of using metal nanoparticle catalysts for water purification and related aqueous-phase applications.

  3. Sensitivities of selenite, selenate, selenomethionine and trimethylselenonium ion in aqueous solution and in blood plasma - ETAAS compared with ICP-MS

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Larsen, E.H.

    1998-01-01

    Aqueous solutions and blood plasma spiked with selenite (Se(IV)), selenate (Se(VI)), selenomethionine (SeMet) or trimethylselenonium (TMSe) iodide were analyzed by Zeeman-corrected electrothermal atomic absorption spectrometry (ETAAS) using palladium as a chemical modifier, and by inductively cou...

  4. Effect of dietary sodium selenite, Se-enriched yeast and Se-enriched Chlorella on egg Se concentration, physical parameters of eggs and laying hen production

    Czech Academy of Sciences Publication Activity Database

    Skřivan, M.; Šimáně, J.; Dlouhá, G.; Doucha, Jiří

    2006-01-01

    Roč. 51, č. 4 (2006), s. 163-167 ISSN 1212-1819 Institutional research plan: CEZ:AV0Z50200510 Keywords : sodium selenite * se-yeast * se-chlorella Subject RIV: EE - Microbiology, Virology Impact factor: 0.421, year: 2006

  5. Transition metal ions and selenite modulate the methylation of arsenite by the recombinant human arsenic (+3 oxidation state) methyltransferase (hAS3MT).

    Science.gov (United States)

    Song, Xiaoli; Geng, Zhirong; Li, Chengying; Hu, Xin; Wang, Zhilin

    2010-05-01

    This report demonstrates that transition metal ions and selenite affect the arsenite methylation by the recombinant human arsenic (+3 oxidation state) methyltransferase (hAS3MT) in vitro. Co(2+), Mn(2+), and Zn(2+) inhibited the arsenite methylation by hAS3MT in a concentration-dependent manner and the kinetics indicated Co(2+) and Mn(2+) to be mixed (competitive and non-competitive) inhibitors while Zn(2+) to be a competitive inhibitor. However, only a high concentration of Fe(2+) could restrain the methylation. UV-visible, CD and fluorescence spectroscopy were used to study the interactions between the metal ions above and hAS3MT. Further studies showed that neither superoxide anion nor hydrogen peroxide was involved in the transition metal ion or selenite inhibition of hAS3MT activity. The inhibition of arsenite methylating activity of hAS3MT by selenite was reversed by 2mM DTT (dithiothreitol) but neither by cysteine nor by beta-mercaptoethanol. Whereas, besides DTT, cysteine can also prevent the inhibition of hAS3MT activity by Co(2+), Mn(2+), and Zn(2+). Free Cys residues were involved in the interactions of transition metal ions or selenite with hAS3MT. It is proposed that the inhibitory effect of the ions (Co(2+), Mn(2+), and Zn(2+)) or selenite on hAS3MT activity might be via the interactions of them with free Cys residues in hAS3MT to form inactive protein adducts.

  6. Selenite -Se(4)- uptake mechanisms in the unicellular green alga Chlamydomonas reinhardtii: bioaccumulation and effects induced on growth and ultrastructure; Mecanismes de prise en charge du selenite - Se(4)-chez l'algue verte unicellulaire Chlamydomonas reinhardtii. Bioaccumulation et effets induits sur la croissance et l'ultrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Morlon, H

    2005-03-15

    Selenium is an essential element, but becomes very toxic at higher concentrations. It occurs in the environment at concentrations ranging from nM to {mu}M and selenium pollution is a worldwide phenomenon. This works aims at improving the knowledge on the interactions between selenite - Se(IV) - and a freshwater phyto-planktonic organism: the unicellular green algae Chlamydomonas reinhardtii. The aim of the performed experiments were: i) to investigate selenite -Se(IV)- uptake mechanisms in C. reinhardtii, using Se{sup 75} as a tracer in short term exposures (<1 h); ii) to assess selenite toxicity as measured with growth impairment and ultrastructural damage (with EDAX-TEM analysis), using long term exposures (96 h) to stable selenite; iii) to evaluate the bioaccumulation capacity of selenite and its potential links with toxicity. Short-term experiments revealed a negligible adsorption and a time-dependent linear absorption with an estimated absorbed flux of about 0.2 nmol.m{sup -2}.nM{sup -1}.h{sup -1}. The uptake was proportional to ambient levels in a broad range of intermediate concentrations (from nM to {mu}M). However, fluxes were higher at very low concentrations (< nM), and decrease with increasing high concentrations ( > {mu}M), suggesting that a high affinity but rapidly saturated transport mechanism could be used at low concentrations, in parallel with a low affinity mechanism that would only saturate at high concentrations ({approx}mM). The latter could involve transporters used by sulphate and nitrates, as suggested by the inhibition of selenite uptake by those element. Se(IV) speciation changes with pH did not induce significant effect on bioavailability. On the basis of the relationship between Se concentration and maximal cell density achieved, an EC50 of 80 {mu}M ([64; 98]) was derived. No adaptation mechanism were observed as the same the same toxicity was quantified for Se-pre-exposed algae. Observations by TEM suggested chloroplasts as the first

  7. Recherche sur l'adaptation aux changements climatiques

    International Development Research Centre (IDRC) Digital Library (Canada)

    Corey Piccioni

    consortiums travaillent dans des zones vulnérables aux changements climatiques en Afrique et en Asie, notamment dans les bassins hydrographiques alimentés .... Le projet de recherche Pathways to Resilience in Semi-Arid Economies (PRISE) vise à réduire les risques et à opti- miser les possibilités de développement ...

  8. Inobservance therapeutique aux anti-retroviraux chez les personnes ...

    African Journals Online (AJOL)

    Buts : Rechercher les facteurs psychologiques ou psychosociaux responsables de l'inobservance thérapeutique (IBT) aux antiretroviraux (ARV) Méthodologie : Il s'agit d'une étude transversale sur 06 mois (mai - octobre 2008) menée au centre de promotion sociale à Lomé chez les personnes vivant avec le VIH (PVVIH) ...

  9. L'adaptation aux changements climatiques | CRDI - Centre de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Appuyée par le CRDI, l'Agence canadienne de développement international et le Fonds international de développement agricole, l'initiative WADImena favorise également les ... Les déchets : pollution visuelle, risque pour la santé et polluants environnementaux. ... UNE PLUS GRANDE RÉSILIENCE AUX CATACLYSMES.

  10. evolution de la frequence et des problemes lies aux evacuations ...

    African Journals Online (AJOL)

    EVOLUTION DE LA FREQUENCE ET DES PROBLEMES LIES AUX. EVACUATIONS SANITAIRES VERS LE SERVICE DE GYNECOLOGIE-OBS-. TETRIQUE DE L'HOPITAL COMMUNAUTAIRE DE BANGUI. SEPOU A.1; GODDOT M.1; NGBALE R.1;GAUNEFET C.E.1; DOMANDE-MODANGA Z.1;. FANDEMA E.1 ...

  11. Une societe aux reperes ambigus | Belinga | African Anthropologist

    African Journals Online (AJOL)

    Une societe aux reperes ambigus. JMZ Belinga. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/aa.v10i1.46101 · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians ...

  12. Programme mondial de recherche sur l'adaptation aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Le Programme mondial de recherche sur l'adaptation aux changements climatiques (maintenant connu sous le nom d'Initiative de recherche concertée sur l'adaptation en Afrique et en Asie, ou IRCAAA) est un nouveau partenariat entre le CRDI et le Department for International Development du Royaume-Uni.

  13. Exposition et intoxication aux pesticides chez des producteurs de ...

    African Journals Online (AJOL)

    Conclusion: Dans la perspective d'une meilleure gestion des risques liés aux pesticides, il est nécessaire que tous les acteurs du secteur cotonnier oeuvrent pour le renforcement des mesures préventives. Mots-clés: Exposition, intoxication, pesticides, coton, Togo. English Title: Pesticides exposure and intoxication among ...

  14. Alimentation, santé et adaptation aux changements climatiques en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Est, sont particulièrement vulnérables, à long terme, aux conséquences des changements climatiques et, à court terme, à la variabilité accrue du climat. Ce projet abordera la question des moyens de subsistance dans le " corridor du bétail " de ...

  15. Partage de connaissances sur l'adaptation aux changements ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    En bref, il sera un outil qui permettra aux africains de prendre charge de la problématique d'adaptation au changements climatiques au niveau local, national et continental, et de ... L'Initiative des conseils subventionnaires de la recherche scientifique en Afrique subsaharienne remporte le prix de la diplomatie scientifique.

  16. Interaction of Coenzyme Q10 with Liposomes and its Impact on Suppression of Selenite – Induced Experimental Cataract

    Directory of Open Access Journals (Sweden)

    Medhat Wahba Shafaa

    2018-03-01

    Full Text Available Purpose: To stress the influence of Coenzyme Q10 (CoQ10 on the structural properties of liposomes as model membranes and to investigate the possible role of CoQ10 or CoQ10 doped in liposomes when topically instilled as eye drops, in preventing cataract. Methods: The molecular interaction between liposomes and Coenzyme Q10 was examined using differential scanning calorimetry (DSC and Fourier transform infrared spectroscopy (FTIR. Rat pups were randomly divided into six groups comprising 15 pups. Group (1, control group. Group (2, untreated model of cataract, received a single subcutaneous injection of sodium selenite. Instillation of pure CoQ10 (Group 3, CoQ10 encapsulated into neutral (Group 4, positive (Group 5 and negative (Group 6 Dipalmitoyl phosphatidylcholine (DPPC liposomes on the opacification of lenses in rat pups after sodium selenite injection was topically received. Results: The incorporated CoQ10 is probably associated with lipid bilayers where it interacts to a large extent and perturbs them. This results in strong broadening and shift to lower temperature (94°C of the major characteristic endothermic peak of pure DPPC at 105°C. FTIR showed that the incorporation of CoQ10 into DPPC induces a conformational change in the polar region of DPPC. Ophthalmological and Biochemical studies revealed that CoQ10 alone followed by negatively charged liposomes doped with CoQ10 are more effective in reducing the progress of cataract as well as improving the lens soluble proteins levels and total antioxidant capacity. Conclusion: The interactions of CoQ10 with membrane systems may contribute to a better understanding of CoQ10 physiological properties and the development of therapeutically advanced systems.

  17. Topologically and geometrically flexible structural units in seven new organically templated uranyl selenates and selenite-selenates

    Science.gov (United States)

    Gurzhiy, Vladislav V.; Kovrugin, Vadim M.; Tyumentseva, Olga S.; Mikhaylenko, Pavel A.; Krivovichev, Sergey V.; Tananaev, Ivan G.

    2015-09-01

    Single crystals of seven novel uranyl oxysalts of selenium with protonated methylamine molecules, [C2H8N]2[(UO2)(SeO4)2(H2O)] (I), [C2H8N]2[(UO2)2(SeO4)3(H2O)] (II), [C4H15N3][H3O]0.5[(UO2)2(SeO4)2.93(SeO3)0.07(H2O)](NO3)0.5 (III), [C2H8N]3[H5O2][(UO2)2(SeO4)3(H2O)2]2(H2O)5 (IV), [C2H8N]2[H3O][(UO2)3(SeO4)4(HSeO3)(H2O)](H2SeO3)0.2 (V), [C4H12N]3[H3O][(UO2)3(SeO4)5(H2O)] (VI), and [C2H8N]3(C2H7N)[(UO2)3(SeO4)4(HSeO3)(H2O)] (VII) have been prepared by isothermal evaporation from aqueous solutions. Their crystal structures have been solved by direct methods and their uranyl selenate and selenite-selenate units investigated using black-and-white graphs from the viewpoints of topology of interpolyhedral linkages and isomeric variations. The crystal structure of IV is based upon complex layers with unique topology, which has not been observed previously in uranyl selenates. Investigations of the statistics and local distribution of the U-Obr-Se bond angles demonstrates that shorter angles associate with undulations, whereas larger angles correspond to planar areas of the uranyl selenite layers.

  18. Pigments content in Сhlorella vulgaris under the influence of the sodium selenite and the ions of metals

    Directory of Open Access Journals (Sweden)

    O. I. Bodnar

    2016-01-01

    Full Text Available We investigated the content of pigments in Chlorella vulgaris Beij. (Chlorophyta under the influence of sodium selenite in concentrations based on Se4+ 0.5, 5.0, 10.0 and 20.0 mg/dm3 during one, three and seven days and under the influence of the simultaneous action of selenite in concentrations 10 mg Se4+/dm3 and ions of Zn2+, Mn2+, Co2+,Cu2+, Fe3+ in concentrations 5.00, 0.25, 0.05, 0.008 and 0.002 mg/dm3over seven days. This research was carried out to establish the conditions for obtaining algal lipidis substance enriched with selenium and biogenic metals in the aquaculture. The content of pigments was determined spectrophotometrically, the cellular walls were separatedby centrifuge in the percoll gradient and investigated microscopically. The pigments content in the Ch. vulgaris increased by 1.5–2.5 times in comparison with the control sample under the influence of 10 mg Se4+/dm3 with and without metal ions, in all variants of experimental influence due to binding of SeО32– with proteins and lipids. We found that selenium was included in all lipid fractions (triacylglycerols, dyacylglycerols, phospholipids, nonetherified fatty acids; the maximum amount of selenium-containing lipids wasrecorded in chloroplasts. The increase in the contents of carotenoids caused by the actions of experimental factors played an exceptional role in the mechanism of antioxidant protection that prevents destruction of chlorophyll and, accordingly, increases its amount in cells. Changes in the functioning of the photosynthetic apparatus of Ch. vulgaris affect the whole complex of metabolic transformation. Thus, the successful cultivation of chlorella, enriched with selenium and biogenic metals, is possible within seven days under the influence of 10 mg Se4+/dm3 and the above-mentioned concentration of metal ions.

  19. Isolation and characterization of an Aux/IAA gene (LaIAA2) from Larix

    African Journals Online (AJOL)

    微软用户

    auxin would be expected to maintain little Aux/IAA protein, having ARFs dissociated from Aux/IAA proteins. This allows for expression changes in typically auxin-regulated genes. The functions of Aux/IAA proteins in growth and development are determined by mutations in Arabidopsis or other plants. The gain-of-function ...

  20. AUX: a scripting language for auditory signal processing and software packages for psychoacoustic experiments and education.

    Science.gov (United States)

    Kwon, Bomjun J

    2012-06-01

    This article introduces AUX (AUditory syntaX), a scripting syntax specifically designed to describe auditory signals and processing, to the members of the behavioral research community. The syntax is based on descriptive function names and intuitive operators suitable for researchers and students without substantial training in programming, who wish to generate and examine sound signals using a written script. In this article, the essence of AUX is discussed and practical examples of AUX scripts specifying various signals are illustrated. Additionally, two accompanying Windows-based programs and development libraries are described. AUX Viewer is a program that generates, visualizes, and plays sounds specified in AUX. AUX Viewer can also be used for class demonstrations or presentations. Another program, Psycon, allows a wide range of sound signals to be used as stimuli in common psychophysical testing paradigms, such as the adaptive procedure, the method of constant stimuli, and the method of adjustment. AUX Library is also provided, so that researchers can develop their own programs utilizing AUX. The philosophical basis of AUX is to separate signal generation from the user interface needed for experiments. AUX scripts are portable and reusable; they can be shared by other researchers, regardless of differences in actual AUX-based programs, and reused for future experiments. In short, the use of AUX can be potentially beneficial to all members of the research community-both those with programming backgrounds and those without.

  1. Special Rhodococcus sp. CR-53 esterase Est4 contains a GGG(A)X-oxyanion hole conferring activity for the kinetic resolution of tertiary alcohols.

    Science.gov (United States)

    Bassegoda, Arnau; Fillat, Amanda; Pastor, F I Javier; Diaz, Pilar

    2013-10-01

    Rhodococci are highly adaptable bacteria, capable to degrade or transform a large number of organic compounds, including recalcitrant or toxic products. However, little information is available on the lipases of the genus Rhodococcus, except for LipR, the first lipase isolated and described from strain Rhodococcus CR-53. Taking into consideration the interest raised by the enzymes produced by actinomycetes, a search for new putative lipases was performed in strain Rhodococcus CR-53. We describe here the isolation, cloning, and characterization of intracellular esterase Est4, a mesophilic enzyme showing preference for short-chain-length acyl groups, without interfacial activation. Est4 displays moderate thermal and pH stability and low tolerance to most tested ions, being inhibited by detergents like sodium dodecyl sulfate and Triton X-100®. Nevertheless, the enzyme shows good long-term stability when stored at 4-20 °C and neutral pH. Amino acid sequence analysis of Est4 revealed a protein of 313 amino acids without a signal peptide, bearing most of the conserved blocks that define bacterial lipase family IV, thus being assigned to this family. Detection of a GGG(A)X oxyanion hole in the enzyme motivated the evaluation of Est4 ability to convert tertiary alcohol esters. The newly discovered esterase Est4 from Rhodococcus CR-53 successfully hydrolyzed the tertiary alcohol esters linalyl acetate, terpinyl acetate, and 1,1,1-trifluoro-2-phenylbut-3-yn-2-yl acetate.

  2. Multispecies Biofilms Transform Selenium Oxyanions into Elemental Selenium Particles: Studies Using Combined Synchrotron X-ray Fluorescence Imaging and Scanning Transmission X-ray Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Soo In; George, Graham N.; Lawrence, John R.; Kaminskyj, Susan G. W.; Dynes, James J.; Lai, Barry; Pickering, Ingrid J.

    2016-10-04

    Selenium (Se) is an element of growing environmental concern, because low aqueous concentrations can lead to biomagnification through the aquatic food web. Biofilms, naturally occurring microbial consortia, play numerous important roles in the environment, especially in biogeochemical cycling of toxic elements in aquatic systems. The complexity of naturally forming multispecies biofilms presents challenges for characterization because conventional microscopic techniques require chemical and physical modifications of the sample. Here, multispecies biofilms biotransforming selenium oxyanions were characterized using X-ray fluorescence imaging (XFI) and scanning transmission X-ray microscopy (STXM). These complementary synchrotron techniques required minimal sample preparation and were applied correlatively to the same biofilm areas. Sub-micrometer XFI showed distributions of Se and endogenous metals, while Se K-edge X-ray absorption spectroscopy indicated the presence of elemental Se (Se0). Nanoscale carbon K-edge STXM revealed the distributions of microbial cells, extracellular polymeric substances (EPS), and lipids using the protein, saccharide, and lipid signatures, respectively, together with highly localized Se0 using the Se LIII edge. Transmission electron microscopy showed the electron-dense particle diameter to be 50–700 nm, suggesting Se0 nanoparticles. The intimate association of Se0 particles with protein and polysaccharide biofilm components has implications for the bioavailability of selenium in the environment.

  3. A novel familial mutation in the PCSK1 gene that alters the oxyanion hole residue of proprotein convertase 1/3 and impairs its enzymatic activity.

    Directory of Open Access Journals (Sweden)

    Michael Wilschanski

    Full Text Available Four siblings presented with congenital diarrhea and various endocrinopathies. Exome sequencing and homozygosity mapping identified five regions, comprising 337 protein-coding genes that were shared by three affected siblings. Exome sequencing identified a novel homozygous N309K mutation in the proprotein convertase subtilisin/kexin type 1 (PCSK1 gene, encoding the neuroendocrine convertase 1 precursor (PC1/3 which was recently reported as a cause of Congenital Diarrhea Disorder (CDD. The PCSK1 mutation affected the oxyanion hole transition state-stabilizing amino acid within the active site, which is critical for appropriate proprotein maturation and enzyme activity. Unexpectedly, the N309K mutant protein exhibited normal, though slowed, prodomain removal and was secreted from both HEK293 and Neuro2A cells. However, the secreted enzyme showed no catalytic activity, and was not processed into the 66 kDa form. We conclude that the N309K enzyme is able to cleave its own propeptide but is catalytically inert against in trans substrates, and that this variant accounts for the enteric and systemic endocrinopathies seen in this large consanguineous kindred.

  4. Supplementation with Sodium Selenite and Selenium-Enriched Microalgae Biomass Show Varying Effects on Blood Enzymes Activities, Antioxidant Response, and Accumulation in Common Barbel (Barbus barbus)

    Czech Academy of Sciences Publication Activity Database

    Kouba, A.; Velíšek, J.; Stará, A.; Masojídek, Jiří; Kozák, P.

    2014-01-01

    Roč. 2014, Article ID 408270 (2014) ISSN 2314-6141 R&D Projects: GA ČR GA521/09/0656; GA MŠk ED2.1.00/03.0110; GA MŠk LO1205; GA MŠk ED2.1.00/01.0024 Grant - others:GA JU(CZ) 087/2013/Z Institutional support: RVO:61388971 Keywords : selenite * selenium * antioxidant response Subject RIV: EE - Microbiology, Virology

  5. A novel function for selenium in biological system: selenite as a highly effective iron carrier for Chinese hamster ovary cell growth and monoclonal antibody production.

    Science.gov (United States)

    Zhang, Jinyou; Robinson, David; Salmon, Peter

    2006-12-20

    As the market for biopharmaceuticals especially monoclonal antibodies (MAbs) rapidly grows, their manufacturing methods are coming under increasing regulatory scrutiny, particularly due to concerns about the potential introduction of adventitious agents from animal-sourced components in the media used for their production in mammalian cell culture. Chinese hamster ovary (CHO) cells are by far the most commonly used production vehicles for these recombinant glycoproteins. In developing animal-component free media for CHO and other mammalian cell lines, the iron-transporter function of serum or human/bovine transferrin is usually replaced by certain organic or inorganic chelators capable of delivering iron for cell respiration and metabolism, but few of them are sufficiently effective. Selenium is a well-known essential trace element (TE) for cell growth and development, and its positive role in biological system includes detoxification of free radicals by activating glutathione peroxidase. In cell culture, selenium in the form of selenite can help cells to detoxify the medium thus protect them from oxidative damage. In this presentation, we describe the discovery and application of a novel function of selenite, that is, as a highly effective carrier to deliver iron for cell growth and function. In our in-house-developed animal protein-free (APF) medium for CHO cells, using an iron-selenite compound to replace the well-established tropolone delivery system for iron led to comparable or better cell growth and antibody production. A high cell density of >10 x 10(6) viable cells/mL and excellent antibody titer of approximately 3 g/L were achieved in 14-day fed-batch cultures in shake flasks, followed by successful scale-up to stirred bioreactors. The preparation of the commercially unavailable iron-selenite compound from respective ions, and its effectiveness in cell-culture performance, were dependent on reaction time, substrates, and other conditions. Copyright 2006

  6. Mechanism of Selenite Removal by a Mixed Adsorbent Based on Fe–Mn Hydrous Oxides Studied Using X-ray Absorption Spectroscopy

    KAUST Repository

    Chubar, Natalia

    2014-11-18

    © 2014 American Chemical Society. Selenium cycling in the environment is greatly controlled by various minerals, including Mn and Fe hydrous oxides. At the same time, such hydrous oxides are the main inorganic ion exchangers suitable (on the basis of their chemical nature) to sorb (toxic) anions, separating them from water solutions. The mechanism of selenite adsorption by the new mixed adsorbent composed of a few (amorphous and crystalline) phases [maghemite, MnCO3, and X-ray amorphous Fe(III) and Mn(III) hydrous oxides] was studied by extended X-ray absorption fine structure (EXAFS) spectroscopy [supported by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) data]. The complexity of the porous adsorbent, especially the presence of the amorphous phases of Fe(III) and Mn(III) hydrous oxides, is the main reason for its high selenite removal performance demonstrated by batch and column adsorption studies shown in the previous work. Selenite was bound to the material via inner-sphere complexation (via oxygen) to the adsorption sites of the amorphous Fe(III) and Mn(III) oxides. This anion was attracted via bidentate binuclear corner-sharing coordination between SeO3 2- trigonal pyramids and both FeO6 and MnO6 octahedra; however, the adsorption sites of Fe(III) hydrous oxides played a leading role in selenite removal. The contribution of the adsorption sites of Mn(III) oxide increased as the pH decreased from 8 to 6. Because most minerals have a complex structure (they are seldom based on individual substances) of various crystallinity, this work is equally relevant to environmental science and environmental technology because it shows how various solid phases control cycling of chemical elements in the environment.

  7. Dynamic equilibrium of endogenous selenium nanoparticles in selenite-exposed cancer cells: a deep insight into the interaction between endogenous SeNPs and proteins.

    Science.gov (United States)

    Bao, Peng; Chen, Song-Can; Xiao, Ke-Qing

    2015-12-01

    Elemental selenium (Se) was recently found to exist as endogenous nanoparticles (i.e., SeNPs) in selenite-exposed cancer cells. By sequestrating critical intracellular proteins, SeNPs appear capable of giving rise to multiple cytotoxicity mechanisms including inhibition of glycolysis, glycolysis-dependent mitochondrial dysfunction, microtubule depolymerization and inhibition of autophagy. In this work, we reveal a dynamic equilibrium of endogenous SeNP assembly and disassembly in selenite-exposed H157 cells. Endogenous SeNPs are observed both in the cytoplasm and in organelles. There is an increase in endogenous SeNPs between 24 h and 36 h, and a decrease between 36 h and 72 h according to transmission electron microscopy results and UV-Vis measurements. These observations imply that elemental Se in SeNPs could be oxidized back into selenite by scavenging superoxide radicals and ultimately re-reduced into selenide; then the assembly and disassembly of SeNPs proceed simultaneously with the sequestration and release of SeNP high-affinity proteins. There is also a possibility that the reduction of elemental Se to selenide pathway may lie in selenite-exposed cancer cells, which results in the assembly and disassembly of endogenous SeNPs. Genome-wide expression analysis results show that endogenous SeNPs significantly altered the expression of 504 genes, compared to the control. The endogenous SeNPs induced mitochondrial impairment and decreasing of the annexin A2 level can lead to inhibition of cancer cell invasion and migration. This dynamic flux of endogenous SeNPs amplifies their cytotoxic potential in cancer cells, thus provide a starting point to design more efficient intracellular self-assembling systems for overcoming multidrug resistance.

  8. Comparison of selenite F, Muller-Kauffmann tetrathionate and Rappaport's medium for salmonella isolation from chicken giblets after pre-enrichment in buffered peptone water.

    OpenAIRE

    Harvey, R. W.; Price, T. H.

    1981-01-01

    Six hundred and eighty three samples of chicken giblets were examined for salmonellas. Three hundred and forty nine of these were neck and crop specimens and 224 were combined liver and heart samples. Two hundred and ten, in all, contained salmonellas. The technique of examination included pre-enrichment in buffered peptone water at 37 degrees C for 18 h and subculture to three enrichment media: Muller-Kauffmann tetrathionate, selenite F and Rappaport's magnesium chloride malachite green brot...

  9. Variation in drug sensitivity of malignant mesothelioma cell lines with substantial effects of selenite and bortezomib, highlights need for individualized therapy.

    Directory of Open Access Journals (Sweden)

    Adam Szulkin

    Full Text Available Malignant mesothelioma cells have an epithelioid or sarcomatoid morphology, both of which may be present in the same tumor. The sarcomatoid phenotype is associated with worse prognosis and heterogeneity of mesothelioma cells may contribute to therapy resistance, which is often seen in mesothelioma. This study aimed to investigate differences in sensitivity between mesothelioma cell lines to anti-cancer drugs. We studied two novel drugs, selenite and bortezomib and compared their effect to four conventional drugs. We also investigated the immunoreactivity of potential predictive markers for drug sensitivity; Pgp, MRP-1, ERCC1, RRM1, TS, xCT and proteasome 20S subunit.We treated six mesothelioma cell lines with selenite, bortezomib, carboplatin, pemetrexed, doxorubicin or gemcitabine as single agents and in combinations. Viability was measured after 24 and 48 hours. Immunocytochemistry was used to detect predictive markers.As a single agent, selenite was effective on four out of six cell lines, and in combination with bortezomib yielded the greatest response in the studied mesothelioma cell lines. Cells with an epithelioid phenotype were generally more sensitive to the different drugs than the sarcomatoid cells. Extensive S-phase arrest was seen in pemetrexed-sensitive cell lines. MRP-1 predicted sensitivity of cell lines to treatment with carboplatin and xCT predicted pemetrexed effect.The observed heterogeneity in sensitivity of mesothelioma cell lines with different morphology highlights the need for more individualized therapy, requiring development of methods to predict drug sensitivity of individual tumors. Selenite and bortezomib showed a superior effect compared to conventional drugs, motivating clinical testing of these agents as future treatment regime components for patients with malignant mesothelioma.

  10. Sensibilisation aux gestes et postures de travail - French version only

    CERN Multimedia

    2004-01-01

    Nous vous proposons un nouveau cours de sécurité lié aux manutentions manuelles (durée 1 jour) : Sensibilisation aux gestes et postures de travail. Si vous êtes amené à manipuler régulièrement des charges lourdes ou volumineuses, cette formation peut vous aider à prévenir les lésions musculaires ou dorsales. A l'issue de cette formation, vous serez capable d'adopter et d'appliquer les principes de base de sécurité physique et d'économie d'efforts dans les manipulations d'objets. Les cours sont pris en charge par la Commission de Sécurité. L'inscription EDH est obligatoire. Pour plus d'information, veuillez consulter les pages Formation & Développement (Groupe Sécurité)

  11. The effect of nano-selenium particles and sodium selenite on humoral immunity indices of quails using foods contaminated with aflatoxin B1

    Directory of Open Access Journals (Sweden)

    Ebrahim Talebi

    2017-08-01

    Full Text Available This experiment was conducted to evaluate the ability of inhibition of aflatoxin B1 by various sources of selenium and to compare the effect of nano selenium and sodium selenite on humoral immunity of quails. The experiment was performed in a completely randomized design (CRD using six treatments and four replicates of ten quail chicks per replicate. Two hundred forty quails were divided in six groups vis. control: without aflatoxin B1 and without selenium. Group2: 1ppm aflatoxin B1 and without selenium. Group3: 1 ppm aflatoxin B1 and 0.3 ppm nano selenium. Group4: 1 ppm aflatoxin B1 and 0.3 ppm sodium selenite. Group5: 1 ppm aflatoxin B1 and 0.6 ppm nano selenium. Group6: 1ppm aflatoxin B1 and 0.6 ppm sodium selenite. To evaluate the humoral immunity response 0.2­ml of sheep red blood cell (SRBC solution was injected into breast muscle of quails at day 35 and blood sampling was conducted after a week. Newcastle vaccine was injected at day 28 and the antibody titer was determined after two weeks. The highest level of titer of antibody against the SRBC solution was related to the group which received 0.06 ppm nano selenium (p

  12. Adaptation aux changements climatiques des bassins versants en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les résultats de recherche seront diffusés dans des publications scientifiques à comité de lecture, dans le cadre d'une interaction critique avec la sphère des politiques, ainsi qu'à l'occasion d'un institut d'été destiné aux chercheurs et ... The Trustees of Ashoka Trust for Research in Ecology and the Environment (ATREE).

  13. Foire aux questions: Bourse de recherche 2018 du CRDI | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Vous remarquerez que d'importantes modifications ont été apportées aux critères d'admissibilité dans les deux dernières années. 2) Je suis étudiant à la maîtrise. Suis-je admissible à une bourse de recherche ? En principe oui. Toutefois, il est important de lire les spécifications du programme qui vous intéresse, car les ...

  14. Pour en finir avec la violence faite aux Palestiniennes | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    4 févr. 2011 ... À Gaza, la violence faite aux femmes est, fondamentalement, synonyme de violence au foyer », affirme Aitemad Muhanna, conseillère en recherche. « Les femmes sont battues par leur mari, battues par leur père et même battues par leurs frères. » Les femmes sont battues parce qu'elles ne remplissent ...

  15. CRDI foire aux questions | CRDI - Centre de recherches pour le ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    1. Quels sont les éléments importants à mentionner dans ma demande d'emploi ? Il importe de démontrer, au moyen d'exemples concrets, de quelle façon vos qualifications correspondent aux exigences du poste en ce qui concerne les études, l'expérience et la langue. 2. Comment saurai-je si ma demande d'emploi a bel ...

  16. La recherche-action participative facilite l'adaptation aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Ces travaux comprenaient un riche portefeuille de recherches sur l'adaptation aux changements climatiques dans le secteur de l'agriculture. La méthodologie privilégiée dans le cadre du programme, la recherche-action participative, s'est avérée fructueuse et a permis de mettre au point et de déployer des solutions ...

  17. Accroissement du recours aux politiques fiscales dans la lutte ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Incidence de la hausse des taxes sur le tabac et du prix des produits du tabac en Ukraine, en Russie et au Bélarus. La recherche destinée aux responsables des politiques de l'Ukraine, de la Russie et du Bélarus mettra en évidence la façon dont les mesures de taxation des produits du tabac peuvent contribuer.

  18. Soutien aux processus d'élaboration des politiques de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les innovations biotechnologiques, ou bio-innovations, peuvent offrir des solutions aux problèmes liés à la sécurité alimentaire, à la pauvreté et à la détérioration de l'environnement. C'est notamment le cas des plantes génétiquement modifiées (GM), qui permettent d'accroître la production alimentaire tout en réduisant ...

  19. Aquaculture intérieure et adaptation aux changements climatiques ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Ce projet porte sur l'élevage du tilapia dans de petits étangs fermiers ou des cages flottantes dans les rivières et les réservoirs du nord de la Thaïlande. Les chercheurs exploreront des façons d'adapter les pratiques aquacoles aux changements climatiques et analyseront la valeur de l'aquaculture comme stratégie ...

  20. Le microdosage des engrais, une innovation qui profite aux femmes ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    6 juin 2016 ... Plus de 1 000 agriculteurs, dont 30 % sont des femmes, ont ainsi obtenu davantage d'engrais qui ont servi à la production de cultures vivrières. Résultat : les femmes ont augmenté les superficies cultivées en ayant recours aux techniques de microdosage des engrais et de collecte des eaux de pluie, ...

  1. Mutational studies of the Aux/IAA proteins in Physcomitrella reveal novel insights into their function.

    Science.gov (United States)

    Tao, Sibo; Estelle, Mark

    2018-02-20

    The plant hormone auxin regulates many aspects of plant growth and development. Auxin signaling involves hormone perception by the TRANSPORT INHIBITOR RESPONSE/AUXIN F-BOX (TIR1/AFB)-Aux/IAA co-receptor system, and the subsequent degradation of the Aux/IAA transcriptional repressors by the ubiquitin proteasome pathway. This leads to the activation of downstream gene expression and diverse physiological responses. Here, we investigate how the structural elements in the Aux/IAAs determine their function in Auxin perception and transcriptional repression. We took advantage of the facile genetics of the moss Physcomitrella patens to determine the activity of wild-type and mutant PpIAA1a proteins in a Δaux/iaa null background. In this way, Aux/IAA function was characterized at the molecular and physiological levels without the interference of genetic redundancy. We identified and characterized degron variants in Aux/IAAs that affect their stability and Auxin response. We also demonstrated that neither the Aux/IAA EAR motif nor Aux/IAA oligomerization is essential for the repressive function of Aux/IAA. Our study demonstrates how key elements within the Aux/IAA proteins fine tune stability and repressor activity, as well as the long-term developmental outcome. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  2. Enrichment and isolation of Bacillus beveridgei sp. nov., a facultative anaerobic haloalkaliphile from Mono Lake, California, that respires oxyanions of tellurium, selenium, and arsenic

    Science.gov (United States)

    Baesman, S.M.; Stolz, J.F.; Kulp, T.R.; Oremland, R.S.

    2009-01-01

    Mono Lake sediment slurries incubated with lactate and tellurite [Te(IV)] turned progressively black with time because of the precipitation of elemental tellurium [Te(0)]. An enrichment culture was established from these slurries that demonstrated Te(IV)-dependent growth. The enrichment was purified by picking isolated black colonies from lactate/Te(IV) agar plates, followed by repeated streaking and picking. The isolate, strain MLTeJB, grew in aqueous Te(IV)-medium if provided with a small amount of sterile solid phase material (e.g., agar plug; glass beads). Strain MLTeJB grew at high concentrations of Te(IV) (~8 mM) by oxidizing lactate to acetate plus formate, while reducing Te(IV) to Te(0). Other electron acceptors that were found to sustain growth were tellurate, selenate, selenite, arsenate, nitrate, nitrite, fumarate and oxygen. Notably, growth on arsenate, nitrate, nitrite and fumarate did not result in the accumulation of formate, implying that in these cases lactate was oxidized to acetate plus CO2. Strain MLTeJB is a low G + C Gram positive motile rod with pH, sodium, and temperature growth optima at 8.5-9.0, 0.5-1.5 M, and 40??C, respectively. The epithet Bacillus beveridgei strain MLTeJBT is proposed. ?? 2009 Springer.

  3. Adsorption Removal of Multiple Dyes Using Biogenic Selenium Nanoparticles from an Escherichia coli Strain Overexpressed Selenite Reductase CsrF

    Directory of Open Access Journals (Sweden)

    Xian Xia

    2018-04-01

    Full Text Available Selenite reductase CsrF overexpressed Escherichia coli was used as a microbial factory to produce Se(0 nanoparticles (Bio-SeNPs. The Bio-SeNPs were characterized by transmission electronic microscopy, element mapping, scanning electron microscopy, energy-dispersive X-ray spectrographs, Zeta-potential, dynamic light scattering, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses. The results indicated that Bio-SeNPs are irregular spheres with diameters from 60 to105 nm and mainly consist of Se(0, proteins and lipids. Furthermore, it exhibited maximum adsorption capacity for anionic dye (congo red at acidic pH and cationic dyes (safranine T and methylene blue at alkaline pH. To gain more insight, adsorption kinetics, adsorption isotherms and adsorption thermodynamics studies were carried out. These results showed that the adsorption capacities of congo red, safranine T and methylene blue were 1577.7, 1911.0 and 1792.2 mg/g, respectively. These adsorption processes were spontaneous and primarily physical reactions. In addition, Bio-SeNPs can be effectively reused by 200 mmol/L NaCl. To the best of our knowledge, this is the first report of adsorption removal dyes by Bio-SeNPs. The adsorption capacities of Bio-SeNPs for congo red, safranine T and methylene blue were 6.8%, 25.2% and 49.0% higher than that for traditional bio-based materials, respectively.

  4. Absorption, distribution, metabolism and excretion of selenium following oral administration of elemental selenium nanoparticles or selenite in rats

    DEFF Research Database (Denmark)

    Löschner, Katrin; Hadrup, Niels; Hansen, Marianne

    2014-01-01

    A suspension of nanoparticles of BSA-stabilized red amorphous elemental selenium (Se) or an aqueous solution of sodium selenite was repeatedly administered by oral gavage for 28 days at 0.05 mg/kg bw/day (low dose) or at 0.5 mg/kg bw/day (high dose) as Se to female rats. Prior to administration...... the concentration of Se was determined by ICP-MS in liver, kidney, urine, feces, stomach, lungs, plasma at µg/g level and in brain and muscle tissue at sub-µg/g level. In order to test if any elemental Se was present in liver, kidney or feces, an in situ derivatization selective to elemental Se was made...... by treatment with sulfite, which resulted in formation of the selenosulfate anion. This Se species was selectively and quantitatively determined by anion exchange HPLC with ICP-MS detection. The results showed that elemental Se was present in the livers, kidneys and feces from animals exposed to low and high...

  5. Adsorption Removal of Multiple Dyes Using Biogenic Selenium Nanoparticles from an Escherichia coli Strain Overexpressed Selenite Reductase CsrF.

    Science.gov (United States)

    Xia, Xian; Zhou, Zijie; Wu, Shijuan; Wang, Dan; Zheng, Shixue; Wang, Gejiao

    2018-04-12

    Selenite reductase CsrF overexpressed Escherichia coli was used as a microbial factory to produce Se(0) nanoparticles (Bio-SeNPs). The Bio-SeNPs were characterized by transmission electronic microscopy, element mapping, scanning electron microscopy, energy-dispersive X-ray spectrographs, Zeta-potential, dynamic light scattering, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses. The results indicated that Bio-SeNPs are irregular spheres with diameters from 60 to105 nm and mainly consist of Se(0), proteins and lipids. Furthermore, it exhibited maximum adsorption capacity for anionic dye (congo red) at acidic pH and cationic dyes (safranine T and methylene blue) at alkaline pH. To gain more insight, adsorption kinetics, adsorption isotherms and adsorption thermodynamics studies were carried out. These results showed that the adsorption capacities of congo red, safranine T and methylene blue were 1577.7, 1911.0 and 1792.2 mg/g, respectively. These adsorption processes were spontaneous and primarily physical reactions. In addition, Bio-SeNPs can be effectively reused by 200 mmol/L NaCl. To the best of our knowledge, this is the first report of adsorption removal dyes by Bio-SeNPs. The adsorption capacities of Bio-SeNPs for congo red, safranine T and methylene blue were 6.8%, 25.2% and 49.0% higher than that for traditional bio-based materials, respectively.

  6. Surfactant modified zeolite as amphiphilic and dual-electronic adsorbent for removal of cationic and oxyanionic metal ions and organic compounds.

    Science.gov (United States)

    Tran, Hai Nguyen; Viet, Pham Van; Chao, Huan-Ping

    2018-01-01

    A hydrophilic Y zeolite was primarily treated with sodium hydroxide to enhance its cation exchange capacity (Na-zeolite). The organo-zeolite (Na-H-zeolite) was prepared by a modification process of the external surface of Na-zeolite with a cationic surfactant (hexadecyltrimethylammonium; HDTMA). Three adsorbents (i.e., pristine zeolite, Na-zeolite, and Na-H-zeolite) were characterized with nitrogen adsorption/desorption isotherms, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, cation exchange capacities, and zeta potential. Results demonstrated that HDTMA can be adsorbed on the surface of Na-zeolite to form patchy bilayers. The adsorption capacity of several hazardous pollutants (i.e., Pb 2+ , Cu 2+ , Ni 2+ , Cr 2 O 7 2- , propylbenzene, ethylbenzene, toluene, benzene, and phenol) onto Na-H-zeolite was investigated in a single system and multiple-components. Adsorption isotherm was measured to further understand the effects of the modification process on the adsorption behaviors of Na-H-zeolite. Adsorption performances indicated that Na-H-zeolite can simultaneously adsorb the metal cations (on the surface not covered by HDTMA), oxyanions (on the surface covered by HDTMA). Na-H-zeolite also exhibited both hydrophilic and hydrophobic surfaces to uptake organic compounds with various water solubilities (from 55 to 75,000mg/L). It was experimentally concluded that Na-H-zeolite is a potential dual-electronic and amphiphilic adsorbent for efficiently removing a wide range of potentially toxic pollutants from aquatic environments. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Un meilleur accès des pauvres aux produits d'assurance : politiques ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Un meilleur accès des pauvres aux produits d'assurance : politiques, réglementation et surveillance de la microassurance. Ce projet a pour objectif de faciliter l'accès des pauvres aux produits d'assurance afin de réduire leur vulnérabilité face aux risques. Pour ce faire, des études de cas seront réalisées dans cinq pays.

  8. Risques et possibilités liés aux changements climatiques pour les ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... sociaux et environnementaux précis. Le projet permettra de diffuser des résultats aux milieux d'affaires, aux professionnels du développement, et aux principaux décideurs. Le partenaire local, Fundación Impulsora de un Nuevo Sector en la Economia Sistema B, possède des bureaux au Chili, en Colombie et au Pérou.

  9. Lancement de l'appel des bourses du CRDI aux chercheurs ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    4 avr. 2018 ... Cet appel à propositions s'adresse aux citoyens canadiens, aux résidents permanents du Canada et aux citoyens de pays en développement inscrits au doctorat dans une université canadienne. Ces bourses servent à financer la réalisation de travaux de recherche sur le terrain visant à améliorer les ...

  10. Résistance aux antibiotiques de Yersinia pestis

    OpenAIRE

    2014-01-01

    2001 : séquençage du génome de Yersinia pestis2004 : séquençage du génome de Rattus norvegicus. Une des préoccupations majeures du Programme national de lutte contre la peste (PNLP) à Madagascar est la surveillance de la sensibilité des souches de Y. pestis aux antibiotiques classiquement utilisables dans le traitement de cette maladie (streptomycine, tétracycline, chloramphénicol, gentamycine, sulfaméthoxazole-triméthoprime, ampicilline). Le PNLP recommande la chimioprophylaxie des sujets co...

  11. Foire aux questions: Bourse de recherche 2017 du CRDI | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    1) Si l'on décide de m'attribuer une bourse de recherche, aurai-je besoin d'un permis de travail ? Veuillez lire les détails sur ce sujet sous la rubrique Admissibilité à la page Web de l'appel. Vous remarquerez que d'importantes modifications ont été apportées aux critères d'admissibilité cette année. 2) Je suis étudiant à la ...

  12. Aspects Phenotypiques De La Resistance Aux Β- Lactamines Des ...

    African Journals Online (AJOL)

    Objectif : Décrire les phénotypes de résistance aux bèta-lactamines des souches de Pseudomonas aeruginosa par la technique de l'antibiogramme en milieu gélosé. Matériel et méthode : Il s'agit d'une étude transversale réalisée du 1er septembre 2011 au 29 février 2012 sur des souches de Pseudomonas aeruginosa ...

  13. Safety Training: Sensibilisation aux gestes et postures de travail

    CERN Multimedia

    Laetitia Laddada

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt.Nous vous proposons un nouveau cours de sécurité lié aux manutentions manuelles (durée 1 jour) : Sensibilisation aux gestes et postures de travail. Si vous êtes amené à manipuler régulièrement des charges lourdes ou volumineuses, cette formation peut vous aider à prévenir les lésions musculaires ou dorsales. A l'issue de cette formation, vous serez capable d'adopter et d'appliquer les principes de base de sécurité physique et d'&e...

  14. Safety Training: Sensibilisation aux gestes et postures de travail

    CERN Multimedia

    Laetitia Laddada

    2004-01-01

    Nous vous proposons un nouveau cours de sécurité lié aux manutentions manuelles (durée 1 jour) : Sensibilisation aux gestes et postures de travail. Si vous êtes amené à manipuler régulièrement des charges lourdes ou volumineuses, cette formation peut vous aider à prévenir les lésions musculaires ou dorsales. A l'issue de cette formation, vous serez capable d'adopter et d'appliquer les principes de base de sécurité physique et d'économie d'efforts dans les manipulations d'objets. Les cours sont pris en charge par la Commission de Sécurité. L'inscription EDH est obligatoire. Pour plus d'information, veuillez consulter les pages Formation & Développement (Groupe Sécurité). FORMATION EN SECURITE SAFETY TRAINING Laetitia Laddada 73811 - 79236 safety.training@cern.ch

  15. A comparison of the uptake of [75Se]Selenite [75Se] Selenomethionine and [35S]methionine by the tissues of ewes and lambs

    International Nuclear Information System (INIS)

    Fuss, C.N.; Godwin, K.O.

    1975-01-01

    The fate of selenium, given as Na 2 75 SeO 3 , or [ 75 Se] selenomethionine, and of [ 35 S]methionine administered intravenously to ewes and lambs, has been examined. The main intention was to follow the incorporation of selenium into protein in a number of tissues, including liver and kidney, and to measure the extent of that incorporation of selenoamino acid, particularly with respect to the administration of selenite. The ewes chosen were lactating ewes with lambs at foot, and the lambs were animals which had been weaned on to fodder low in selenium and were recovering from white muscle disease with selenium therapy. These two experimental situations were chosen as they offered conditions under which selenium incorporation might be considered to be maximal. Entry of isotope into milk was rapid and was greater when 75 Se was given as the selenoamino acid than as selenite. In both ewes and lambs greater amounts of activity, derived from selenite, were bound to plasma proteins than to the proteins of milk. This was particularly evident in samples taken some hours after administration. This ability of the plasma to bind selenium was demonstrated by alkaline dialysis. Small, though significant amounts of selenium, derived from Na 2 75 SeO 3 , were incorporated as selenoamino acids into the proteins of liver, kidney and pancreas, as well as into the proteins of milk and plasma. In ewes, both selenomethionine and selenocystine were identified chromatographically in enzyme digests of defatted liver and kidney. Some differences occurred in the distribution of labelled compounds in organs from lactating ewes and recovering lambs. The incorporation of selenium into protein is discussed briefly in relation to the recent findings of an association between selenium and the enzyme glutathione peroxidase. (author)

  16. Removal mechanism of selenite by Fe{sub 3}O{sub 4}-precipitated mesoporous magnetic carbon microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jianwei; Fu, Fenglian, E-mail: fufenglian2006@163.com; Ding, Zecong; Li, Na; Tang, Bing

    2017-05-15

    Highlights: • MCMSs were prepared via green hydrothermal carbonization and coprecipitation. • MCMSs displayed effective removal of Se(IV) from wastewater. • Se(IV) formed inner-sphere complexes with MCMSs and was reduced to insoluble Se{sup 0}. • MCMSs can be easily separated and recycled by an external magnetic field. - Abstract: A mesoporous composite of magnetic carbon microspheres (MCMSs) was synthesized via introducing Fe{sub 3}O{sub 4} nanoscale particles to the surface of carbon microspheres (CMSs) by coprecipitation. Scanning electron microscopy and transmission electron microscopy showed the Fe{sub 3}O{sub 4} nanoscale particles were dispersedly immobilized on the surface of CMSs. The MCMSs demonstrated effective removal of selenite (Se(IV)) from wastewater. MCMSs showed the regular pattern where the lower pH value, the lower residual Se(IV) concentration. The coexisting sulfate, nitrate, chloride, carbonate, and silicate had no significant effect on Se(IV) removal, whereas phosphate hindered the removal of Se(IV) by competing with Se(IV) and formed inner–sphere complexes with Fe{sub 3}O{sub 4} on the surface of MCMSs. Through X–ray photoelectron spectroscopy analysis, Se(IV) can not only form inner–sphere complexes with MCMSs, but also be reduced to insoluble elemental selenium (Se{sup 0}) by Fe{sub 3}O{sub 4} which was oxidized and formed γ–Fe{sub 2}O{sub 3}. Moreover, the superparamagnetic MCMSs can be easily separated from solution by means of an external magnetic field. The high removal efficiency for Se(IV) and rapid separability of MCMSs made them promising materials for the application in the practice.

  17. Selenium Accumulation Characteristics and Biofortification Potentiality in Turnip (Brassica rapa var. rapa Supplied with Selenite or Selenate

    Directory of Open Access Journals (Sweden)

    Xiong Li

    2018-01-01

    Full Text Available Selenium (Se is an essential trace element for humans. About 70% of the regions in China, including most of the Tibetan Plateau, are faced with Se deficiency problems. Turnip is mainly distributed around the Tibetan Plateau and is one of the few local crops. In the present study, we compared the absorption and translocation differences of Se (IV selenite and Se (VI selenate in turnip. The results showed that Se treatment, either by soil addition (0.2–2 mg Se kg−1 dry soil or by foliar spraying (50–200 mg L−1 Se, could significantly increase the Se concentrations in turnips, and 0.5 mg Se (IV or Se (VI kg−1 dry matter in soils could improve the biomasses of turnips. Moreover, turnip absorbed significantly more Se (VI than Se (IV at the same concentration and also transferred much more Se (VI from roots to leaves. Based on the Se concentrations, as well as the bioconcentration factors and translocation coefficients, we considered that turnip might be a potential Se indicator plant. Subsequently, we estimated the daily Se intake for adults based on the Se concentrations in turnip roots. The results indicated that Se (IV should be more suitable as an artificial Se fertilizer for turnips, although the levels found in most samples in this study could cause selenosis to humans. In addition, we also estimated the optimum and maximum Se concentrations for treating turnips based on the linear relations between Se concentrations in turnip roots and Se treatment concentrations. The results provided preliminary and useful information about Se biofortification in turnips.

  18. Change of choline compounds in sodium selenite-induced apoptosis of rats used as quantitative analysis by in vitro 9.4T MR spectroscopy

    DEFF Research Database (Denmark)

    Cao, Zhen; Wu, Lin-Ping; Li, Yun-Xia

    2008-01-01

    AIM: To study liver cell apoptosis caused by the toxicity of selenium and observe the alteration of choline compounds using in vitro 9.4T high resolution magnetic resonance spectroscopy. METHODS: Twenty male Wistar rats were randomly divided into two groups. The rats in the treatment group were...... intraperitoneally injected with sodium selenite and the control group with distilled water. All rats were sacrificed and the livers were dissected. (1)H-MRS data were collected using in vitro 9.4T high resolution magnetic resonance spectrometer. Spectra were processed using XWINNMR and MestRe-c 4.3. HE and TUNEL...

  19. Protection de la communauté urbaine de Cotonou face aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Protection de la communauté urbaine de Cotonou face aux changements climatiques (Bénin). Ce projet vise à renforcer la capacité d'adaptation des populations de la communauté urbaine de Cotonou aux inondations. Il le fera en mettant en oeuvre un processus participatif de diagnostic, d'analyse et de planification de ...

  20. Un observatoire régional pour l'adaptation des producteurs aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    22 avr. 2016 ... La présente note est le fruit de deux projets subventionnés par le programme Adaptation aux changements climatiques en Afrique : le projet de recherche InfoClim : plateforme pour l'adaptation des communautés vulnérables aux ... Participatory GIS for resource management in Africa: Taking stock.

  1. Un accès difficile aux services essentiels | CRDI - Centre de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    29 oct. 2015 ... Mise à jour | Villes sûres et inclusives​ Quelles sont les causes de la violence urbaine ? Un accès difficile aux services essentiels peut fomenter la concurrence et les conflits entre les groupes. Des solutions possibles ? Rendre accessibles aux communautés vulnérables l'eau potable, les services ...

  2. Carthage : la ‘Fontaine aux mille amphores’

    Directory of Open Access Journals (Sweden)

    Jean-Pierre Laporte

    2018-02-01

    Full Text Available Découverte par L. Carton en 1918, puis dégagée sous sa direction en 1919, la « Fontaine aux 1000 amphores » est aujourd’hui inaccessible. On peut cependant l’étudier grâce à différents textes, un plan et une coupe, ainsi que des cartes postales des années 1920-1935 environ . On pourra se demander quelle était la nature et la destination exacte de ce monument qui a connu plusieurs importants remaniements successifs. Il s’agissait en fait d’une source sacrée, probablement aménagée en nymphée, avec toutes les caractéristiques, maintenant bien connues, de ce genre d’établissement.

  3. L’ethnologue aux prises avec les archives - Introduction

    Directory of Open Access Journals (Sweden)

    Marie-Dominique Mouton

    2008-08-01

    Full Text Available Les textes présentés ici invitent à une réflexion sur les matériaux de terrain et plus largement sur la relation qui unit l’ethnologue aux archives, qu’il s’agisse des siennes, données vivantes, inspiratrices de sa recherche, de celles de ses aînés, devenues objets d’étude après leur dépôt dans une institution, ou de toutes les autres archives, constituées et rassemblées, à différentes époques, dans des perspectives administratives, juridiques, historiques ou religieuses, envisagées ici au tr...

  4. A group of new selenite-chlorides of strontium and d-metals (Co,Ni): Synthesis, thermal behavior and crystal chemistry

    International Nuclear Information System (INIS)

    Berdonosov, Peter S.; Olenev, Andrey V.; Kuznetsov, Alexei N.; Dolgikh, Valery A.

    2009-01-01

    The new selenite-chlorides with composition Sr 3 (SeO 3 ) 2 Cl 2 (I) and Sr 2 M(SeO 3 ) 2 Cl 2 (M=Co, Ni (II and III)) were obtained. They crystallize in monoclinic system I: space group C2/m, a=13.203(2) A, b=5.5355(8) A, c=6.6170(10) A, β=95.89(1) o , Z=2; II Space group P2 1 /n, a=5.3400(10) A, b =6.4279(6) A, c=12.322(1) A, β=92.44(1) o , Z=2; III: space group P2 1 /n, a=5.3254(11) A, b=6.4363(13) A, c=12.197(2), β=92.53(3) o , Z=2. All three compounds are constructed in the same manner. Sr polyhedra form infinite layers, which are interconnected into a 3D framework by means of Sr polyhedra in the case of I or Co and Ni polyhedra in the case of II and III. Se atoms are situated inside the channels of the 3D framework. The topological analysis of ELF for I confirmed that the lone electron pairs of SeO 3 groups are located inside these channels. - Graphical abstract: Three new selenite-chlorides Sr 3 (SeO 3 ) 2 Cl 2 and Sr 2 M(SeO 3 ) 2 Cl 2 (M= Co,Ni)

  5. Monsieur Etienne Blanc Premier vice-président de la Région Auvergne-Rhône-Alpes Délégué aux finances, à l'administration générale, aux économies budgétaires et aux politiques transfrontalières

    CERN Multimedia

    Bennett, Sophia Elizabeth

    2017-01-01

    Monsieur Etienne Blanc Premier vice-président de la Région Auvergne-Rhône-Alpes Délégué aux finances, à l'administration générale, aux économies budgétaires et aux politiques transfrontalières

  6. Change of selenium in plasma of dairy cows receiving two levels of sodium-selenite during the transition period

    Directory of Open Access Journals (Sweden)

    A. Giubbiotti

    2010-04-01

    Full Text Available With the aim to study the plasma Se content during transition period, 2 groups of 12 dairy cows were monitored the month before and after calving. In stall 1 (S1 cows were tied and individually fed, in stall2 (S2 cows were free and fed TMR. In both stalls cows were supplied with Se as Na-selenite. In S1 3 mg/d of Se were fed mixed with corn silage while, in S2, Se was offered with TMR, in dry period 2 mg/d were added with a mineral-vitamin supplement, in lactation 2.6 mg/d (when DMI was 22.2 kg/d with the concentrate. Forages, the same for both stalls, and concentrates were sampled for chemical composition and Se determination. Cows were checked for milk yield and its content of somatic cells (SCC, health problems, and bled for Se determination in plasma. Average Se intake was higher in S1, in both dry (4.08 vs 2.76 mg/d and lactating (5.80 vs 2.11 mg/d period. Besides the supplementation, differences depended on high Se intake in S1 with the concentrate (increased after calving to 11.5 kg/DM on d 30 and containing 0.24 mg/kg DM of Se. According to the intake, plasma Se content resulted higher in S1 in dry (1.20 vs 0.74 μmol/L and lactating (1.47 vs 0.62 μmol/L cows. In close-up plasma Se decreased in both groups, in first days of lactation increased in S1, while decreased in S2 to level indicating a deficient intake (0.50 μmol/L. These results confirm the link between Se intake and its plasma level. Finally, Se plasma content did not seem related to cow health status during transition period.

  7. Transferts aux petites échelles : application au rayonnement thermique, aux forces de Casimir et à la conduction thermique

    OpenAIRE

    Joulain, Karl

    2006-01-01

    Cette habilitation traite des transferts de chaleur et de quantité de mouvement aux courtes échelles d'espace et de temps. Une première partie du travail s'interesse au propriétés du rayonnement thermique en champ proche. Il est montré qu'en présence de matériaux supportant des ondes de surface, le champ électromagnétique d'origine thermique peut voir ses propriétés de cohérence changées entre le champ proche et le champ lointain, en particulier lorsque les matériaux mis en jeu supportent des...

  8. Variation in auxin sensing guides AUX/IAA transcriptional repressor ubiquitylation and destruction.

    Science.gov (United States)

    Winkler, Martin; Niemeyer, Michael; Hellmuth, Antje; Janitza, Philipp; Christ, Gideon; Samodelov, Sophia L; Wilde, Verona; Majovsky, Petra; Trujillo, Marco; Zurbriggen, Matias D; Hoehenwarter, Wolfgang; Quint, Marcel; Calderón Villalobos, Luz Irina A

    2017-06-07

    Auxin is a small molecule morphogen that bridges SCF TIR1/AFB -AUX/IAA co-receptor interactions leading to ubiquitylation and proteasome-dependent degradation of AUX/IAA transcriptional repressors. Here, we systematically dissect auxin sensing by SCF TIR1 -IAA6 and SCF TIR1 -IAA19 co-receptor complexes, and assess IAA6/IAA19 ubiquitylation in vitro and IAA6/IAA19 degradation in vivo. We show that TIR1-IAA19 and TIR1-IAA6 have distinct auxin affinities that correlate with ubiquitylation and turnover dynamics of the AUX/IAA. We establish a system to track AUX/IAA ubiquitylation in IAA6 and IAA19 in vitro and show that it occurs in flexible hotspots in degron-flanking regions adorned with specific Lys residues. We propose that this signature is exploited during auxin-mediated SCF TIR1 -AUX/IAA interactions. We present evidence for an evolving AUX/IAA repertoire, typified by the IAA6/IAA19 ohnologues, that discriminates the range of auxin concentrations found in plants. We postulate that the intrinsic flexibility of AUX/IAAs might bias their ubiquitylation and destruction kinetics enabling specific auxin responses.

  9. The identification and characterization of specific ARF-Aux/IAA regulatory modules in plant growth and development.

    Science.gov (United States)

    Krogan, Naden T; Berleth, Thomas

    2015-01-01

    The current model of auxin-inducible transcription describes numerous regulatory interactions between AUXIN RESPONSE FACTORs (ARFs) and Aux/IAAs. However, specific relationships between individual members of these families in planta remain largely uncharacterized. Using a systems biology approach, the entire suite of Aux/IAA genes directly regulated by the developmentally pivotal ARF MONOPTEROS (MP) was recently determined for multiple Arabidopsis tissue types. This study showed that MP directly targets distinct subclades of Aux/IAAs, revealing potential regulatory modules of redundantly acting Aux/IAAs involved in MP-dependent processes. Further, functional analyses indicated that the protein products of these targeted Aux/IAAs negatively feedback on MP. Thus, comprehensive identification of Aux/IAAs targeted by individual ARFs will generate biologically meaningful networks of ARF-Aux/IAA regulatory modules controlling distinct plant pathways.

  10. Outils d'acces aux donnees d'un PLC "Automate Web Access (AWA)"

    CERN Document Server

    Palluel, J; CERN. Geneva. AB Department

    2004-01-01

    Cette note presente un moniteur d'acces aux donnees d'un PLC Schneider ou Siemens, pouvant fonctionner sur n'importe quelle plateforme (Windows, Linux...) equipee d'un navigateur WEB sans telechargement de logiciel ("Applets").

  11. La fabrique des sciences des institutions aux pratiques

    CERN Document Server

    Benninghoff, Martin; Crettaz von Roten, Fabienne; Merz, Martina

    2006-01-01

    Aujourd'hui, les façons de produire, d'organiser, d'évaluer et d'utiliser les savoirs sont en profond débat. De plus en plus, l'Etat, la société civile et l'économie tentent d'influencer les activités des universités et des laboratoires de recherche. Ces développements mettent à l'épreuve tout à la fois les fondements des systèmes d'enseignement supérieur et de recherche, l'autonomie des institutions scientifiques, la définition des frontières des savoirs et l'acceptation des sciences. Dans des contextes suisses et européens, cet ouvrage s'intéresse aux manières dont les sciences et les technologies sont fabriquées, en analysant leurs institutions et les pratiques. A partir d'une approche relationnelle, les sciences et les technologies sont conçues comme des phénomènes profondément sociaux, culturels et politiques. Une telle démarche déstabilise les visions parfois idéalisées et stéréotypées de la construction des savoirs. Des études de cas détaillées décrivent des phénomè...

  12. Aux limites de la physique les paradoxes quantiques

    CERN Document Server

    Rothen, François

    2012-01-01

    Dans l’esprit des pères fondateurs de la science moderne, les phénomènes matériels se déroulent selon un schéma unique. La cause précède nécessairement l’effet, et la connaissance de l’effet permet de remonter à la cause. Sur la scène de la nature, le hasard n’occupe qu’une place congrue. On ne fait appel à lui que pour pallier notre ignorance. Dans les années 1920, la révolution quantique bouleverse ce cadre rigide. Elle accorde une place de choix au hasard, si malmené jusqu’alors, puis elle met en scène une constellation de phénomènes inexplicables aux yeux de la science dite classique. Après une courte introduction historique, l’auteur met ses lecteurs au contact de certains de ces phénomènes si contraires à l’intuition. Refusant l’aide du langage mathématique, il les convie à pénétrer dans un monde quantique qui déconcerte le novice avant de l’éblouir par sa nouveauté et sa cohérence. Un accent particulier est mis sur une application nouvelle de la physiqu...

  13. La transformation de la recherche aux Suds: politiques et résultats

    International Development Research Centre (IDRC) Digital Library (Canada)

    David O'Brien;Rigas Arvanitis

    des résultats de la recherche scientifique ; et les leçons relatives aux politiques publiques. Les propositions ... transformations et les écarts par rapport aux cadres de définition des politiques précédents. Dans leur ... l'impact de la recherche ainsi que des développements nouveaux ou expérimentaux, y compris des outils.

  14. Impact, en ce qui a trait aux revenus et à la santé, de la ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Impact, en ce qui a trait aux revenus et à la santé, de la restructuration de la taxe d'accise sur le tabac aux Philippines. Un projet de loi déposé par le gouvernement des Philippines visant à augmenter de 215 % la taxe d'accise sur le tabac est susceptible d'avoir une incidence sur la lutte antitabac et la consommation de ...

  15. Amélioration de la sécurité alimentaire et nutritionnelle aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Aux Philippines, on estime à 14 % la proportion d'écoliers qui souffrent de malnutrition aiguë. Les écoles offrent des voies stratégiques et ciblées pour fournir une alimentation nutritive aux enfants et, indirectement, à leurs familles et leurs collectivités. Un projet de recherche d'une durée de trois ans (de 2012 à 2015) a mis ...

  16. Résilience des villes face aux changements climatiques en Asie du ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Résilience des villes face aux changements climatiques en Asie du Sud-Est. La préparation aux changements climatiques est une tâche énorme pour les gouvernements de la région du Mékong, en Asie du Sud-Est. Le présent projet les aidera à gérer ces changements dans un contexte caractérisé par des capacités ...

  17. Adjoint aux conférences et au soutien administratif (h/f) | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    L' adjoint aux conférences et au soutien administratif est responsable du suivi et de la mise à jour de l'ensemble de formulaires, contrats et modèles utilisés dans les fonctions de gestion d'événements ainsi que de l'administration du site intranet des Services de conférence. L'adjoint aux conférences et au soutien ...

  18. Il faut agir pour aider Le Cap à s'adapter aux changements climatiques

    International Development Research Centre (IDRC) Digital Library (Canada)

    9 juin 2016 ... Ce livre porte sur les expériences menées au Cap et décrit les mesures novatrices qui y sont prises en vue de l'adaptation de la ville aux changements climatiques. On y présente les résultats du projet Gouvernance axée sur la collaboration : gestion des risques associés aux inondations et à l'élévation du ...

  19. Création d'une assise d'expertise en adaptation aux changements ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    De 2006 à 2012, 212 organismes ont participé à des projets de recherche subventionnés par le programme Adaptation aux changements climatiques en Afrique (ACCA), et 89 % d'entre eux étaient des organismes africains. Comme il n'y avait guère d'établissements africains qui se penchaient sur les questions reliées aux ...

  20. Renforcement de la capacité d'adaptation aux changements ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Renforcement de la capacité d'adaptation aux changements climatiques en Zambie et au Zimbabwe. Ce projet vise à améliorer les mesures incitatives et les possibilités qui s'offrent aux ménages du sud de la Zambie et du sud-ouest du Zimbabwe pour composer avec les changements climatiques. Pour ce faire, les ...

  1. L'intensite du capital au Canada et aux Etats-Unis, 1987 a 2003

    OpenAIRE

    Baldwin, John R.; Fisher, Anthony; Gu, Wulong; Lee, Frank C; Robidoux, Benoit

    2008-01-01

    Les donnees officielles produites par les organismes statistiques ne sont pas toujours ideales aux fins de comparaisons entre pays en raison de differences relatives aux sources de donnees et de la methodologie. Les analystes qui procedent a des comparaisons entre pays doivent choisir avec soin entre plusieurs options et parfois adapter les donnees a leurs propres fins. Dans le present document, nous elaborons des estimations comparables du stock de capital pour examiner l'intensite relative ...

  2. À la suite de la parution d'un rapport sur les subventions aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    7 juin 2016 ... Scott Wallace / The World Bank. John Cockburn. La protection sociale par le truchement de transferts en espèces peut-elle aider le Ghana à réduire l'écart grandissant que ses subventions aux carburants ont contribué à créer entre les riches et les pauvres ? Une récente étude sur les subventions aux ...

  3. Mettre un terme à la violence faite aux femmes | CRDI - Centre de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    13 nov. 2012 ... Il est essentiel que la violence faite aux femmes et aux filles sorte au grand jour, qu'on cesse de la justifier au nom de la “culture” ou de la “tradition” et que, collectivement, nous refusions d'excuser les ... Asia Justice and Rights (AJAR) ... Elle s'inscrit dans une culture où elle est sournoisement admise.

  4. Aux/IAA Gene Family in Plants: Molecular Structure, Regulation, and Function

    Directory of Open Access Journals (Sweden)

    Jie Luo

    2018-01-01

    Full Text Available Auxin plays a crucial role in the diverse cellular and developmental responses of plants across their lifespan. Plants can quickly sense and respond to changes in auxin levels, and these responses involve several major classes of auxin-responsive genes, including the Auxin/Indole-3-Acetic Acid (Aux/IAA family, the auxin response factor (ARF family, small auxin upregulated RNA (SAUR, and the auxin-responsive Gretchen Hagen3 (GH3 family. Aux/IAA proteins are short-lived nuclear proteins comprising several highly conserved domains that are encoded by the auxin early response gene family. These proteins have specific domains that interact with ARFs and inhibit the transcription of genes activated by ARFs. Molecular studies have revealed that Aux/IAA family members can form diverse dimers with ARFs to regulate genes in various ways. Functional analyses of Aux/IAA family members have indicated that they have various roles in plant development, such as root development, shoot growth, and fruit ripening. In this review, recently discovered details regarding the molecular characteristics, regulation, and protein–protein interactions of the Aux/IAA proteins are discussed. These details provide new insights into the molecular basis of the Aux/IAA protein functions in plant developmental processes.

  5. Histotopography of the radiopharmaceuticals 75Se-selenomethionine and 75Se-selenite in critical organs of adult and embryonic mice

    International Nuclear Information System (INIS)

    Khant, S.E.; Norets, T.A.

    1981-01-01

    Adult male and pregnant mice received 75 Se-labelled methionine and selenite, resp. The critical organs and the embryos were examined histoautoradiographically at different time intervals as to the organ distribution of the radiopharmaceuticals. All organs revealed a heterogeneity of the 75 Se distribution with an intensity being unequally organo-specific and depending on the type of the radiopharmaceutical. 75 Se-selenomethionine was deposited mainly in functional areas of kidneys, liver, bone marrow and testes thus causing a long-term retention and an intensive irradiation of these organs. In the embryos 75 Se-seleno-methionine was distributed unequally preferring liver, hematopoietic areas of the bone marrow and the lens

  6. Selenite reduction by the obligate aerobic bacterium Comamonas testosteroni S44 isolated from a metal-contaminated soil

    DEFF Research Database (Denmark)

    Zheng, Shixue; Su, Jing; Wang, Liang

    2014-01-01

    ) and EDS Elemental Mapping showed no element Se and SeNPs were produced inside cells whereas Se(IV) was reduced to red-colored selenium in the cytoplasmic fraction in presence of NADPH. Tungstate inhibited Se(VI) but not Se(IV) reduction, indicating the Se(IV)-reducing determinant does not contain......Background: Selenium (Se) is an essential trace element in most organisms but has to be carefully handled since there is a thin line between beneficial and toxic concentrations. Many bacteria have the ability to reduce selenite (Se(IV)) and (or) selenate (Se(VI)) to red elemental selenium...... that is less toxic. Results: A strictly aerobic bacterium, Comamonas testosteroni S44, previously isolated from metal(loid)-contaminated soil in southern China, reduced Se(IV) to red selenium nanoparticles (SeNPs) with sizes ranging from 100 to 200 nm. Both energy dispersive X-ray Spectroscopy (EDX or EDS...

  7. Properties of the antiferromagnetic selenite MnSeO3 and its non-magnetic analogue ZnSnO3 from first principles calculations

    Science.gov (United States)

    Honer, C. J.; Prosniewski, M. J.; Putatunda, A.; Singh, David J.

    2017-10-01

    We report the properties of the antiferromagnetic selenite MnSeO3 and the non-magnetic analogue ZnSeO3, based on first principles calculations. These compounds are rare examples of ABO3 perovskites with a tetravalent A-site and a divalent B-site. The electronic structure is discussed in the context of the bonding and crystal structure. There is cross-gap hybridization between the O p states that form the valence bands of these compounds and the unoccupied p states of Se, reflecting the lone pair physics that leads to the strong off-centering of Se from the perovskite A-site. The G-type antiferromagnetism of MnSeO3 is a local moment in nature arising from high spin Mn2+ with short range interactions. Additionally, there is an interesting spin-dependent hybridization of Mn d and O p states analogous to that in colossal magnetoresistance manganites.

  8. Protein-protein interaction and gene co-expression maps of ARFs and Aux/IAAs in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Sarbottam ePiya

    2014-12-01

    Full Text Available The phytohormone auxin regulates nearly all aspects of plant growth and development. Based on the current model in Arabidopsis thaliana, Auxin/indole-3-acetic acid (Aux/IAA proteins repress auxin-inducible genes by inhibiting auxin response transcription factors (ARFs. Experimental evidence suggests that heterodimerization between Aux/IAA and ARF proteins are related to their unique biological functions. The objective of this study was to generate the Aux/IAA-ARF protein-protein interaction map using full length sequences and locate the interacting protein pairs to specific gene co-expression networks in order to define tissue-specific responses of the Aux/IAA-ARF interactome. Pairwise interactions between 19 ARFs and 29 Aux/IAAs resulted in the identification of 213 specific interactions of which 79 interactions were previously unknown. The incorporation of co-expression profiles with protein-protein interaction data revealed a strong correlation of gene co-expression for 70% of the ARF-Aux/IAA interacting pairs in at least one tissue/organ, indicative of the biological significance of these interactions. Importantly, ARF4-8 and 19, which were found to interact with almost all Aux-Aux/IAA showed broad co-expression relationships with Aux/IAA genes, thus, formed the central hubs of the co-expression network. Our analyses provide new insights into the biological significance of ARF-Aux/IAA associations in the morphogenesis and development of various plant tissues and organs.

  9. Protein-protein interaction and gene co-expression maps of ARFs and Aux/IAAs in Arabidopsis.

    Science.gov (United States)

    Piya, Sarbottam; Shrestha, Sandesh K; Binder, Brad; Stewart, C Neal; Hewezi, Tarek

    2014-01-01

    The phytohormone auxin regulates nearly all aspects of plant growth and development. Based on the current model in Arabidopsis thaliana, Auxin/indole-3-acetic acid (Aux/IAA) proteins repress auxin-inducible genes by inhibiting auxin response transcription factors (ARFs). Experimental evidence suggests that heterodimerization between Aux/IAA and ARF proteins are related to their unique biological functions. The objective of this study was to generate the Aux/IAA-ARF protein-protein interaction map using full length sequences and locate the interacting protein pairs to specific gene co-expression networks in order to define tissue-specific responses of the Aux/IAA-ARF interactome. Pairwise interactions between 19 ARFs and 29 Aux/IAAs resulted in the identification of 213 specific interactions of which 79 interactions were previously unknown. The incorporation of co-expression profiles with protein-protein interaction data revealed a strong correlation of gene co-expression for 70% of the ARF-Aux/IAA interacting pairs in at least one tissue/organ, indicative of the biological significance of these interactions. Importantly, ARF4-8 and 19, which were found to interact with almost all Aux-Aux/IAA showed broad co-expression relationships with Aux/IAA genes, thus, formed the central hubs of the co-expression network. Our analyses provide new insights into the biological significance of ARF-Aux/IAA associations in the morphogenesis and development of various plant tissues and organs.

  10. THE EFFECTS OF SODIUM SELENITE AND SELENIZED YEAST SUPPLEMENTATION INTO DIET FOR LAYING HENS ON SELECTED QUALITATIVE PARAMETERS OF TABLE EGGS

    Directory of Open Access Journals (Sweden)

    HENRIETA ARPÁŠOVÁ

    2009-10-01

    Full Text Available In this experiment the effects of supplementation of the diet for laying hens with sodium selenite (SS or selenized yeast (SY on whole egg and egg shell quality of layers were studied. The chickens of Shaver Starcross 288 strain were randomly divided at the day of hatching into 4 groups (n=12; in each. The birds were fed from Day 1 of life to 9 months of age with diets differing in amounts and/or forms of selenium. Control group received basal diet (BD containing selenium naturally occurring in feeds (0.1 mg Se/kg of dry matter (DM. First and second experimental group of chickens were fed with a same BD enriched with equivalent dose of Se 0.4 mg/kg DM in form of sodium selenite or selenized yeast, respectively. The feed for third experimental group of birds consisted of BD supplemented with selenized yeast to the final amount of selenium 1.0 mg/kg DM. The egg weight was significantly higher in the groups with SY supplementation only. On the contrary the egg shell ratio was significantly lower in the groups with SY supplementation in both amounts. The width of egg was significantly increased in the groups with selenium supplementation in both forms. The value of egg shell strength was significantly decreased in group with SY in the highest amount 0.9 mg/kg DM The average egg shell thickness was the highest in the experimental group with Se-yeast in amount 0.9 mg/kg DM, however different was not significant compared with control group. The results showed that the most of selected parameters of egg quality appeared to be significantly influenced by selenium supplementation into laying hen’s basal diet.

  11. Effects of foliar dressing of selenite and silicate alone or combined with different soil ameliorants on the accumulation of As and Cd and antioxidant system in Brassica campestris.

    Science.gov (United States)

    Ding, Yongzhen; Wang, Yongjiu; Zheng, Xiangqun; Cheng, Weimin; Shi, Rongguang; Feng, Renwei

    2017-08-01

    This study was conducted to investigate the possibility of using a combined technology to synchronously reduce As and Cd accumulation in the edible parts of Brassica campestris. The results showed that a foliar application of selenite (Se) and silicon (Si) combined with soil ameliorants (including Ca-Mg-P fertilizer, sodium silicate and red mud) showed limited effects on the growth of B. campestris. The As concentration in the leaves of B. campestris in all treatments was below the Chinese safety standard. When sodium silicate and Ca-Mg-P fertilizer were added to the soil, the additional foliar application of Se and Si could in some cases help further reduce the concentrations of As and Cd in the leaves of B. campestris. However, when red mud was applied to the soil, the foliar application of Se and Si enhanced the Cd concentration in the leaves of B. campestris. In most cases, high levels of soil ameliorants plus foliar application of Se and Si significantly enhanced the As concentrations in both the soil solution and the roots of B. campestris but reduced the soil solution Cd concentration and the leaf As concentration. Most of the treatments reduced the thiobarbituric acid reactive substances (TBARS) concentration in the leaves of B. campestris, and the foliar application of Se and Si helped the soil ameliorants alleviate the oxidative stress resulting from As and Cd exposure. In this study, several treatments significantly increased the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX). However, the enzymes peroxidase (POD) and catalase (CAT) were not induced by most treatments. In summary, the combined treatment of 1gkg -1 Ca-Mg-P fertilizer plus foliar spraying 2mmolL -1 sodium selenite was most effective in reducing the Cd concentration and a rather strong ability to reduce the As concentration and trigger the activities of SOD and APX in the leaves of B. campestris. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Des tables pascales aux tables astronomiques et retour.

    Directory of Open Access Journals (Sweden)

    Max Lejbowicz

    2006-05-01

    Full Text Available L’article étudie la naissance et le développement du calendrier ecclésiastique chrétien, i. e. le comput, depuis les premiers témoignages de la célébration annuelle de la résurrection de Jésus jusqu’aux traductions des tables astronomiques arabes au xiie siècle. Il privilégie les procédures qui aboutissent à la détermination des dates pascales et à leur mise en forme tabulaire. Les analyses sont conduites à partir d’un double point de vue. L’un est scientifique. Il s’appuie sur les données astronomiques retenues par Ptolémée et sur l’apport de la tradition mathématique grecque au calcul par approximations. Les cycles soli-lunaires sont posés à partir des fractions continues et le cycle soli-hebdomadaire à partir du plus petit commun multiple. Le second point de vue est social : l’unification du comput participe à celle de la chrétienté comprise comme une configuration politico-religieuse. Deux conclusions s’imposent. Quelle que soit l’importance que la civilisation médiévale a attribuée au comput, il reste que : 1 / les Pâques sont porteuses de significations irréductibles aux techniques chronométriques qui inscrivent cette fête dans le déroulement de l’année ; 2 / ces techniques ont toutefois marqué profondément les curiosités intellectuelles des Latins et les ont préparé à accueillir avec ferveur les zīj et la numération de position.The article studies the birth and development of the Christian ecclesiastical calendar, i.e. the computus, from the first witnesses to the yearly celebration of the resurrection of Jesus to the translations of arabic astronomical tables in the 12th century. It focuses on the procedures which resulted in determinig the dates of Easter and their being put into tabular form. These analyses were undertaken from two perspectives. One was scientific, relying on the astronomical data preserved by Ptolemy and on the contribution of the Greek mathematical

  13. Villes côtières en danger aux Philippines : investir dans la résilience ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les villes côtières des Philippines sont très vulnérables aux effets des changements climatiques et aux catastrophes qui en découlent. Un examen des plans et des programmes de gestion des catastrophes en vigueur aux Philippines montre que la plupart d'entre eux ne s'appuient pas sur une méthode d'appréciation ...

  14. Accorder l'accès aux données économiques pour prévenir les ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Ce projet permettra aux chercheurs, aux responsables des politiques et aux défenseurs de la santé publique de prendre davantage connaissance des données économiques et stratégiques susceptibles de fonder des politiques de lutte contre le tabac et l'alcool en Afrique subsaharienne, et de jouir d'un meilleur accès à ...

  15. Des usines à la campagne aux villes industrielles

    Directory of Open Access Journals (Sweden)

    Laure Bonnaud

    2005-06-01

    Full Text Available L’objet de cet article est de retracer sociologiquement l’histoire du droit des installations classées ou plutôt de la partie de ce droit qui concerne l’urbanisation autour des établissements dangereux et qui entend ainsi encadrer les relations entre la ville et l’industrie. Cette perspective permet d’envisager deux aspects complémentaires de cette question : d’une part, on examine le droit comme une façon de représenter un problème et notamment comment la place de la question urbaine y a été pensée et définie ; d’autre part, on s’intéresse aux règles juridiques comme des outils, des ressources de catégories, de concepts qui définissent des cadres pour l’action publique. Ainsi, l'histoire du droit des installations classées contribue à mettre en lumière la façon dont la gestion de la proximité ville/industrie articule en permanence (mais selon des modalités qui varient au fil du temps les dimensions sociales, économiques et environnementales qui permettent aujourd'hui d'appréhender et de définir le développement durable.The main aim of this paper is to relate the history of a part of the environmental French law, the one which govern the urban development in the vicinity of the dangerous chemical plants. From a sociological point of view, two aspects of this issue may be simultaneously analysed. In one hand, we examine the law as a way to represent the problem of cohabitation between urban area and industry: how this question has been successively thought out and defined? On the other hand, we take an interest in the juridical rules considered as tools, resources and concepts for public management. According to this approach, the history of this part of French law highlight how urban planning and risk management permanently link the social, economical and environmental dimensions of sustainability. But it shows also that those three factors play a part that vary from time to time.

  16. In vitro effects of selenite and mercuric chloride on liver thiobarbituric acid-reactive substances and non-protein thiols from rats: influences of dietary cholesterol and polyunsaturated and saturated fatty acids.

    Science.gov (United States)

    Farina, Marcelo; Soares, Félix Antunes; Feoli, Ana; Roehring, Cíntia; Brusque, Ana Maria; Rotta, Liane; Perry, Marcos Luis; Souza, Diogo Onofre; Rocha, João Batista T

    2003-06-01

    We measured the in vitro effects of mercuric chloride (Hg2+) and selenite (Se4+) on hepatic 2-thiobarbituric acid-reactive substances (TBARS) and non-protein sulfhydryl (NPSH) levels of rats fed diets enriched with polyunsaturated or saturated fatty acids with and without cholesterol. Male Wistar rats (21 d old) were assigned to one of four groups and fed diets containing 20% soybean oil, 20% soybean oil plus 1% cholesterol, 20% coconut oil, or coconut oil plus 1% cholesterol. After the feeding period (6 wk), body weight gain was equal in all groups. TBARS levels and NPSH content were measured after in vitro exposure to mercuric chloride (100 microM) and sodium selenite (25 microM) for 1 h. The lipid peroxidation, measured as TBARS levels in the control group, were statistically higher in hepatic homogenates of rats fed diets containing soybean oil than in groups fed coconut oil (P = 0.009). However, cholesterol supplementation did not change TBARS levels. Selenite alone did not modify TBARS production, whereas mercury alone significantly increased TBARS levels. Moreover, Se4+ protected against mercury-induced lipid peroxidation only in rats fed diets containing coconut oil. In the control group, dietary fat acids did not change NPSH levels. Selenite produced higher oxidative effects toward NPSH content, whereas Hg2+ decreased NPSH levels only in liver from rats fed diets containing soybean oil. NPSH levels were higher after concomitant exposure to Se4+ and Hg2+ chloride that after exposure to Se4+ alone, suggesting an interaction between Hg2+ and Se4+. Catalase activity was higher in animals fed diets containing soybean oil. Dietary cholesterol decreased glutathione peroxidase activity. Together these results indicated that the protective effect of Se4+ against mercury-induced lipid peroxidation depends on dietary fat saturation.

  17. Ti1-xAux Alloys: Hard Biocompatible Metals and Their Possible Applications

    Science.gov (United States)

    Svanidze, Eteri; Besara, Tiglet; Ozaydin, M. Fevzi; Xin, Yan; Han, Ke; Liang, Hong; Siegrist, Theo; Morosan, Emilia

    2015-03-01

    The search for new hard materials is often challenging from both theoretical and experimental points of view. Furthermore, using materials for biomedical applications calls for alloys with high biocompatibility which are even more sparse. The Ti1-xAux (0 . 22 metallicity, high biocompatibility, low wear, reduced friction, potentially high radio opacity, as well as osseointegration. All these properties render the Ti1-xAux alloys particularly useful for orthopedic, dental, and prosthetic applications, where they could be used as both permanent and temporary components. Additionally, the ability of Ti1-xAux alloys to adhere to ceramic parts could reduce the weight and cost of these components. The work at Rice was supported by NSF DMR 0847681 (E.M. and E.S.).

  18. Crystal structure and magnetic properties of two new cobalt selenite halides: Co5(SeO3)4 X 2 (X=Cl, Br)

    International Nuclear Information System (INIS)

    Becker, Richard; Prester, Mladen; Berger, Helmuth; Hui Lin, Ping; Johnsson, Mats; Drobac, Djuro; Zivkovic, Ivica

    2007-01-01

    Two new isostructural cobalt selenite halides Co 5 (SeO 3 ) 4 Cl 2 and Co 5 (SeO 3 ) 4 Br 2 have been synthesized. They crystallize in the triclinic system space group P-1 with the following lattice parameters for Co 5 (SeO 3 ) 4 Cl 2 : a=6.4935(8) A, b=7.7288(8) A, c=7.7443(10) A, α=66.051(11) o , β=73.610(11) o , γ=81.268(9) o , and Z=1. The crystal structures were solved from single-crystal X-ray data, R1=3.73 and 4.03 for Co 5 (SeO 3 ) 4 Cl 2 and Co 5 (SeO 3 ) 4 Br 2 , respectively. The new compounds are isostructural to Ni 5 (SeO 3 ) 4 Br 2 . Magnetic susceptibility measurements on oriented single-crystalline samples show anisotropic response in a broad temperature range. The anisotropic susceptibility is quantitatively interpreted within the zero-field splitting schemes for Co 2+ and Ni 2+ ions. Sharp low-temperature susceptibility features, at T N =18 and 20 K for Co 5 (SeO 3 ) 4 Cl 2 and Co 5 (SeO 3 ) 4 Br 2 , respectively, are ascribed to antiferromagnetic ordering in a minority magnetic subsystem. In isostructural Ni 5 (SeO 3 ) 4 Br 2 magnetically ordered subsystem represents a majority fraction (T N =46 K). Nevertheless, anisotropic susceptibility of Ni 5 (SeO 3 ) 4 Br 2 is dominated at low temperatures by a minority fraction, subject to single-ion anisotropy effects and increasing population of S z =0 (singlet) ground state of octahedrally coordinated Ni 2+ . - Graphical abstract: Two new iso-structural cobalt selenite halides Co 5 (SeO 3 ) 4 Cl 2 and Co 5 (SeO 3 ) 4 Br 2 have been synthesized which are iso-structural to Ni 5 (SeO 3 ) 4 Br 2 . Magnetic susceptibility measurements on oriented single-crystalline samples show anisotropic response in a broad temperature range, revealing significant single-ion anisotropy effects

  19. Comparing the influence of selenite (Se4+) and selenate (Se6+) on the inhibition of the mercury (Hg) phytotoxicity to pak choi.

    Science.gov (United States)

    Tran, Thi Anh Thu; Dinh, Quang Toan; Cui, Zeiwei; Huang, Jie; Wang, Dan; Wei, Tianjiao; Liang, Dongli; Sun, Xin; Ning, Ping

    2018-01-01

    Selenite (Se (IV)) and selenate (Se (IV)) have recently been demonstrated to be equally effective in inhibiting mercury (Hg) phytotoxicity to plants. This assertion is still unclear. In this study, we aimed to explore the potential effects of Se species (Se 4+ and Se 6+ ) on the inhibition of the mercury (Hg) bioavailability to pak choi in dry land. Pot experiments with exposure to different dosages of mercuric chloride (HgCl 2 ) and selenite (Na 2 SeO 3 ) or selenate (Na 2 SeO 4 ) were treated. To compare the influence of Se (IV) and Se (VI) on the bioaccumulation and bioavailability of Hg, the levels of total Hg in different pak choi (Brassica chinensis L.) tissues (roots and shoots) and the distribution changes of Hg fractions in soil before planting and after harvest were determined as well as the Hg I R values in soils (relative binding intensity) were analyzed. Results showed that application Se (IV) reduced the concentrations of Hg in pak choi roots more than Se (VI). Hg concentrations were also decreased in pak choi shoots in Se (IV) treatments, while which notably increased in Se (VI) treatments. Thus, Se (IV) plays a more important role than Se (VI) in limiting the absorption and bioaccumulation of Hg in pak choi. Moreover, this inhibition may only significantly occur when Se (IV) is at an appropriate level (2.5mg/kg). In addition, the good correlations between the proportions of mobile Hg fractions (soluble and exchangeable fractions), I R values with the Hg concentrations in plants were observed. This affirmed the importance of the Hg fractions transformation and the I R indicator of Hg in the assessment of their bioavailability. Our findings regarding the importance of Se (IV) influence in reducing Hg bioaccumulation not only provided the correct appraisal about the effect of Se species on the inhibition of the Hg phytotoxicity to pak choi in dry land, but also be a good reference for selecting Se fertilizer forms (Se 4+ or Se 6+ ). Copyright © 2017

  20. Formation en TIC destinée aux personnes handicapées en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Formation en TIC destinée aux personnes handicapées en Amérique latine. En Amérique latine et dans les Caraïbes, les personnes handicapées représentent environ 10 % de la population. La population de cette région affiche des taux de pauvreté et de chômage élevés; assurer des moyens de subsistance décents aux ...

  1. Genome-Wide Analysis and Characterization of Aux/IAA Family Genes in Brassica rapa.

    Science.gov (United States)

    Paul, Parameswari; Dhandapani, Vignesh; Rameneni, Jana Jeevan; Li, Xiaonan; Sivanandhan, Ganesan; Choi, Su Ryun; Pang, Wenxing; Im, Subin; Lim, Yong Pyo

    2016-01-01

    Auxins are the key players in plant growth development involving leaf formation, phototropism, root, fruit and embryo development. Auxin/Indole-3-Acetic Acid (Aux/IAA) are early auxin response genes noted as transcriptional repressors in plant auxin signaling. However, many studies focus on Aux/ARF gene families and much less is known about the Aux/IAA gene family in Brassica rapa (B. rapa). Here we performed a comprehensive genome-wide analysis and identified 55 Aux/IAA genes in B. rapa using four conserved motifs of Aux/IAA family (PF02309). Chromosomal mapping of the B. rapa Aux/IAA (BrIAA) genes facilitated understanding cluster rearrangement of the crucifer building blocks in the genome. Phylogenetic analysis of BrIAA with Arabidopsis thaliana, Oryza sativa and Zea mays identified 51 sister pairs including 15 same species (BrIAA-BrIAA) and 36 cross species (BrIAA-AtIAA) IAA genes. Among the 55 BrIAA genes, expression of 43 and 45 genes were verified using Genebank B. rapa ESTs and in home developed microarray data from mature leaves of Chiifu and RcBr lines. Despite their huge morphological difference, tissue specific expression analysis of BrIAA genes between the parental lines Chiifu and RcBr showed that the genes followed a similar pattern of expression during leaf development and a different pattern during bud, flower and siliqua development stages. The response of the BrIAA genes to abiotic and auxin stress at different time intervals revealed their involvement in stress response. Single Nucleotide Polymorphisms between IAA genes of reference genome Chiifu and RcBr were focused and identified. Our study examines the scope of conservation and divergence of Aux/IAA genes and their structures in B. rapa. Analyzing the expression and structural variation between two parental lines will significantly contribute to functional genomics of Brassica crops and we belive our study would provide a foundation in understanding the Aux/IAA genes in B. rapa.

  2. Genome-Wide Analysis and Characterization of Aux/IAA Family Genes in Brassica rapa.

    Directory of Open Access Journals (Sweden)

    Parameswari Paul

    Full Text Available Auxins are the key players in plant growth development involving leaf formation, phototropism, root, fruit and embryo development. Auxin/Indole-3-Acetic Acid (Aux/IAA are early auxin response genes noted as transcriptional repressors in plant auxin signaling. However, many studies focus on Aux/ARF gene families and much less is known about the Aux/IAA gene family in Brassica rapa (B. rapa. Here we performed a comprehensive genome-wide analysis and identified 55 Aux/IAA genes in B. rapa using four conserved motifs of Aux/IAA family (PF02309. Chromosomal mapping of the B. rapa Aux/IAA (BrIAA genes facilitated understanding cluster rearrangement of the crucifer building blocks in the genome. Phylogenetic analysis of BrIAA with Arabidopsis thaliana, Oryza sativa and Zea mays identified 51 sister pairs including 15 same species (BrIAA-BrIAA and 36 cross species (BrIAA-AtIAA IAA genes. Among the 55 BrIAA genes, expression of 43 and 45 genes were verified using Genebank B. rapa ESTs and in home developed microarray data from mature leaves of Chiifu and RcBr lines. Despite their huge morphological difference, tissue specific expression analysis of BrIAA genes between the parental lines Chiifu and RcBr showed that the genes followed a similar pattern of expression during leaf development and a different pattern during bud, flower and siliqua development stages. The response of the BrIAA genes to abiotic and auxin stress at different time intervals revealed their involvement in stress response. Single Nucleotide Polymorphisms between IAA genes of reference genome Chiifu and RcBr were focused and identified. Our study examines the scope of conservation and divergence of Aux/IAA genes and their structures in B. rapa. Analyzing the expression and structural variation between two parental lines will significantly contribute to functional genomics of Brassica crops and we belive our study would provide a foundation in understanding the Aux/IAA genes in B. rapa.

  3. Intégration des sexospécificités et de l'équité aux recherches et aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Plus particulièrement, les extrants comprendront un cadre permettant de comprendre la violence à l'endroit des femmes, l'adaptation du modèle des " trois délais " en matière de mortalité maternelle aux milieux pauvres et fortement sexistes ainsi qu'une procédure de gestion des complications et des risques liés à la ...

  4. Report of transparency and nuclear safety 2007 CEA Fontenay aux Roses; Rapport transparence et securite nucleaire 2007 CEA Fontenay aux Roses

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    This report presents the activities of the CEA Center of Fontenay aux roses for the year 2007. After many years of decommissioning and dismantling of nuclear installations, the Center is now devoted (since 2005) to the development of research programmes on biology and biomedical technologies. The actions concerning the safety, the radiation protection, the significant events, the release control and the environmental impacts and the wastes stored on the center are discussed. (A.L.B.)

  5. Amélioration de la résilience aux répercussions des changements ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Amélioration de la résilience aux répercussions des changements climatiques sur les ressources en eau dans le corridor du bétail en Ouganda ... Il est particulièrement vulnérable aux changements climatiques. Ce projet fournira ... Water Resource Management and the Changing Climate in Angola's Coastal Settlements.

  6. Adaptation aux répercussions de l'élévation du niveau de la mer ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    , la pollution, l'utilisation intensive des terres, la croissance démographique et la dégradation des écosystèmes. Elles sont par ailleurs exposées aux répercussions de la hausse du niveau de la mer et notamment aux inondations. Réduire la ...

  7. Photoactivated CRY1 and phyB Interact Directly with AUX/IAA Proteins to Inhibit Auxin Signaling in Arabidopsis.

    Science.gov (United States)

    Xu, Feng; He, Shengbo; Zhang, Jingyi; Mao, Zhilei; Wang, Wenxiu; Li, Ting; Hua, Jie; Du, Shasha; Xu, Pengbo; Li, Ling; Lian, Hongli; Yang, Hong-Quan

    2017-12-19

    Light is a key environmental cue that inhibits hypocotyl cell elongation through the blue and red/far-red light photoreceptors cryptochrome- and phytochrome-mediated pathways in Arabidopsis. In contrast, as a pivotal endogenous phytohormone auxin promotes hypocotyl elongation through the auxin receptors TIR1/AFBs-mediated degradation of AUX/IAA proteins (AUX/IAAs). However, the molecular mechanisms underlying the antagonistic interaction of light and auxin signaling remain unclear. Here, we report that light inhibits auxin signaling through stabilization of AUX/IAAs by blue and red light-dependent interactions of cryptochrome 1 (CRY1) and phytochrome B with AUX/IAAs, respectively. Blue light-triggered interactions of CRY1 with AUX/IAAs inhibit the associations of TIR1 with AUX/IAAs, leading to the repression of auxin-induced degradation of these proteins. Our results indicate that photoreceptors share AUX/IAAs with auxin receptors as the same direct downstream signaling components. We propose that antagonistic regulation of AUX/IAA protein stability by photoreceptors and auxin receptors allows plants to balance light and auxin signals to optimize their growth. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

  8. Charge-based fractionation of oxyanion-forming metals and metalloids leached from recycled concrete aggregates of different degrees of carbonation: a comparison of laboratory and field leaching tests.

    Science.gov (United States)

    Mulugeta, Mesay; Engelsen, Christian J; Wibetoe, Grethe; Lund, Walter

    2011-02-01

    The release and charge-based fractionation of As, Cr, Mo, Sb, Se and V were evaluated in leachates generated from recycled concrete aggregates (RCA) in a laboratory and at a field site. The leachates, covering the pH range 8.4-12.6, were generated from non-carbonated, and artificially and naturally carbonated crushed concrete samples. Comparison between the release of the elements from the non-carbonated and carbonated samples indicated higher solubility of the elements from the latter. The laboratory leaching tests also revealed that the solubility of the elements is low at the "natural pH" of the non-carbonated materials and show enhancement when the pH is decreased. The charge-based fractionation of the elements was determined by ion-exchange solid phase extraction (SPE); it was found that all the target elements predominantly existed as anions in both the laboratory and field leachates. The high fraction of the anionic species of the elements in the leachates from the carbonated RCA materials verified the enhanced solubility of the oxyanionic species of the elements as a result of carbonation. The concentrations of the elements in the leachates and SPE effluents were determined by inductively coupled plasma mass spectrometry (ICP-MS). Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Evolution Analysis of the Aux/IAA Gene Family in Plants Shows Dual Origins and Variable Nuclear Localization Signals

    Science.gov (United States)

    Wu, Wentao; Liu, Yaxue; Wang, Yuqian; Li, Huimin; Liu, Jiaxi; Tan, Jiaxin; He, Jiadai; Bai, Jingwen

    2017-01-01

    The plant hormone auxin plays pivotal roles in many aspects of plant growth and development. The auxin/indole-3-acetic acid (Aux/IAA) gene family encodes short-lived nuclear proteins acting on auxin perception and signaling, but the evolutionary history of this gene family remains to be elucidated. In this study, the Aux/IAA gene family in 17 plant species covering all major lineages of plants is identified and analyzed by using multiple bioinformatics methods. A total of 434 Aux/IAA genes was found among these plant species, and the gene copy number ranges from three (Physcomitrella patens) to 63 (Glycine max). The phylogenetic analysis shows that the canonical Aux/IAA proteins can be generally divided into five major clades, and the origin of Aux/IAA proteins could be traced back to the common ancestor of land plants and green algae. Many truncated Aux/IAA proteins were found, and some of these truncated Aux/IAA proteins may be generated from the C-terminal truncation of auxin response factor (ARF) proteins. Our results indicate that tandem and segmental duplications play dominant roles for the expansion of the Aux/IAA gene family mainly under purifying selection. The putative nuclear localization signals (NLSs) in Aux/IAA proteins are conservative, and two kinds of new primordial bipartite NLSs in P. patens and Selaginella moellendorffii were discovered. Our findings not only give insights into the origin and expansion of the Aux/IAA gene family, but also provide a basis for understanding their functions during the course of evolution. PMID:28991190

  10. Auxin sensitivities of all Arabidopsis Aux/IAAs for degradation in the presence of every TIR1/AFB.

    Science.gov (United States)

    Shimizu-Mitao, Yasushi; Kakimoto, Tatsuo

    2014-08-01

    Auxin plays a key role in regulation of almost all processes of plant growth and development. Different physiological processes are regulated by different ranges of auxin concentrations; however, the underlying mechanisms creating these differences are largely unknown. The first step of auxin signaling is auxin-dependent interaction of an auxin receptor with transcriptional co-repressors (Aux/IAA), which leads to Aux/IAA degradation. Arabidopsis has six homologous auxin receptors (TIR1 and five AFBs), 29 Aux/IAA proteins and two types of active auxins, IAA and phenylacetic acid (PAA). Therefore, a large number of possible combinations between these three factors may contribute to the creation of complex auxin responses. Using a yeast heterologous reconstitution system, we investigated auxin-dependent degradation of all Arabidopsis Aux/IAAs in combination with every TIR or AFB receptor component. We found that TIR1 and AFB2 were effective in mediating Aux/IAA degradation. We confirmed that the Aux/IAA domain II, which binds TIR1, is essential for degradation. IAA and other natural auxins, 4-chloroindole-3-acetic acid (4-Cl-IAA) and PAA, induced Aux/IAA degradation; and IAA and 4-Cl-IAA had higher activity than PAA. Effective auxin concentrations for Aux/IAA degradation depended on both Aux/IAAs and TIR1 or AFB2 receptors, which is consistent with the Aux/IAA-TIR1/AFB co-receptor concept. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  11. Evolution Analysis of the Aux/IAA Gene Family in Plants Shows Dual Origins and Variable Nuclear Localization Signals

    Directory of Open Access Journals (Sweden)

    Wentao Wu

    2017-10-01

    Full Text Available The plant hormone auxin plays pivotal roles in many aspects of plant growth and development. The auxin/indole-3-acetic acid (Aux/IAA gene family encodes short-lived nuclear proteins acting on auxin perception and signaling, but the evolutionary history of this gene family remains to be elucidated. In this study, the Aux/IAA gene family in 17 plant species covering all major lineages of plants is identified and analyzed by using multiple bioinformatics methods. A total of 434 Aux/IAA genes was found among these plant species, and the gene copy number ranges from three (Physcomitrella patens to 63 (Glycine max. The phylogenetic analysis shows that the canonical Aux/IAA proteins can be generally divided into five major clades, and the origin of Aux/IAA proteins could be traced back to the common ancestor of land plants and green algae. Many truncated Aux/IAA proteins were found, and some of these truncated Aux/IAA proteins may be generated from the C-terminal truncation of auxin response factor (ARF proteins. Our results indicate that tandem and segmental duplications play dominant roles for the expansion of the Aux/IAA gene family mainly under purifying selection. The putative nuclear localization signals (NLSs in Aux/IAA proteins are conservative, and two kinds of new primordial bipartite NLSs in P. patens and Selaginella moellendorffii were discovered. Our findings not only give insights into the origin and expansion of the Aux/IAA gene family, but also provide a basis for understanding their functions during the course of evolution.

  12. Cassia tora leaves modulates selenite cataract by enhancing antioxidant status and preventing cytoskeletal protein loss in lenses of Sprague Dawley rat pups.

    Science.gov (United States)

    Sreelakshmi, V; Abraham, Annie

    2016-02-03

    Cataract is the clouding or opacity that develops in the eye's lens and is considered to be an unavoidable consequence of aging due to irreversible lens damage. Free radicals and oxidant species are reported to be the major factor responsible for the onset and pathology of cataract. No pharmacological measures are formulated to treat cataract blindness and surgical removal of the opaque lens is the only remedy till date. Boosting of antioxidant potential of the lens is proved to prevent cataract and many indigenous plants have been screened for anticataractogenic potential in the last decades. The objective of the present study was to determine whether Cassia tora leaves; the plant employed in traditional medicine for eye rejuvenation and ailments, can prevent cataract in neonatal rats. Cataract was induced by a single subcutaneous injection of sodium selenite at a dose of 4 μg/g body weight on the 10th day and Cassia tora leaves was administered orally from 8th day upto 12th day at a concentration of 5 μg/g body weight. After 30 days; lens morphology, oxidant-antioxidant equilibrium, glutathione metabolism, cytoskeletal protein/gene expressions were monitored. Lens morphology, biochemical analysis and expression studies supported the anticataractogenic effect of Cassia tora leaves. In summary, it can be suggested that the consumption of these leaves afford protection to the lens with its antioxidant action and seems to be a new therapeutic approach against cataract by preventive protection. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. New inorganic (an)ion exchangers with a higher affinity for arsenate and a competitive removal capacity towards fluoride, bromate, bromide, selenate, selenite, arsenite and borate

    KAUST Repository

    Chubar, Natalia

    2011-12-01

    Highly selective materials and effective technologies are needed to meet the increasingly stronger drinking water standards for targeted ionic species. Inorganic ion exchangers based on individual and mixed-metal hydrous oxides (or mixed adsorbents that contain inorganic ion exchangers in their composition) are adsorptive materials that are capable of lowering the concentrations of anionic contaminants, such as H 2AsO 4 -, H 3AsO 3, F -, Br -, BrO 3 -, HSeO 4 -, HSeO 3 - and H 3BO 3, to 10 μg/L or less. To achieve a higher selectivity towards arsenate, a new ion exchanger based on Mg-Al hydrous oxides was developed by a novel, cost-effective and environmentally friendly synthesis method via a non-traditional (alkoxide-free) sol-gel approach. The exceptional adsorptive capacity of the Mg-Al hydrous oxides towards H 2AsO 4 - (up to 200 mg[As]/gdw) is due to the high affinity of this sorbent towards arsenate (steep equilibrium isotherms) and its fast adsorption kinetics. Because of the mesoporous (as determined by N 2 adsorption and SEM) and layered (as determined by XRD and FTIR) structure of the ion-exchange material as well as the abundance of anion exchange sites (as determined by XPS and potentiometric titration) on its surface the material demonstrated very competitive (or very high) removal capacity towards other targeted anions, including fluoride, bromide, bromate, selenate, selenite, and borate. © 2011 IWA Publishing.

  14. Optical absorption of selenite single crystals subjected to high electric fields and irradiated with X-rays or γ-rays

    International Nuclear Information System (INIS)

    Mishra, Sakuntala; Rao, A.V.K.; Rao, K.V.

    1988-01-01

    Measurements of the optical absorption coefficient of selenite single crystals show two peaks at 236 and 400 nm when plotted as a function of wavelength. These peaks decrease with increasing irradiation time for both γ and X-rays. Subsequent thermal bleaching increases the absorption coefficient at all wavelengths and flattens out the peaks at 140 0 C and 330 0 C respectively. The imposition of an a.c. or d.c. field prior to irradiation preserves the thermal bleaching characteristics with an overall increase in absorption coefficient. These effects are attributed to two different types of bond formed by water of crystallization giving rise to the two absorption peaks. Irradiation may destroy some of the bands of loosely bound water molecules near defect regions leading to a decrease in absorption. Thermal bleaching removes water molecules reducing the transparency of the samples, the more strongly bound molecules being removed at the higher temperature. Irradiation after a.c. or d.c. field treatment may introduce more defect regions enabling the removal of more water molecules by bleaching and hence increasing the absorption. (U.K.)

  15. Allium cepa L. Response to Sodium Selenite (Se(IV)) Studied in Plant Roots by a LC-MS-Based Proteomic Approach.

    Science.gov (United States)

    Karasinski, Jakub; Wrobel, Kazimierz; Corrales Escobosa, Alma Rosa; Konopka, Anna; Bulska, Ewa; Wrobel, Katarzyna

    2017-05-17

    Liquid chromatography-high-resolution mass spectrometry was used for the first time to investigate the impact of Se(IV) (10 mgSe L -1 as sodium selenite) on Allium cepa L. root proteome. Using MaxQuant platform, more than 600 proteins were found; 42 were identified based on at least 2 razor + unique peptides, score > 25, and were found to be differentially expressed in the exposed versus control roots with t-test difference > ±0.70 (p roots. Different abundances of proteins involved in transcriptional regulation, protein folding/assembly, cell cycle, energy/carbohydrate metabolism, stress response, and antioxidant defense were found in the exposed vs nonexposed roots. New evidence was obtained on the alteration of sulfur metabolism due to S-Se competition in A. cepa L. which, together with the original analytical approach, is the main scientific contribution of this study. Specifically, proteins participating in assimilation and transformation of both elements were affected; formation of volatile Se compounds seemed to be favored. Changes observed in methionine cycle suggested that Se(IV) stress might repress methylation capability in A. cepa L., potentially limiting accumulation of Se in the form of nonprotein methylated species and affecting adversely transmethylation-dependent signaling pathways.

  16. Solutions d'adaptation liées aux changements climatiques et à l'eau ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Ce projet vise à faire connaître les solutions d'adaptation concrètes aux changements climatiques découlant de recherches financées par le CRDI. ... Le projet sera mis en oeuvre dans le cadre d'un partenariat de recherche entre Local Governments for Sustainability Management (ICLEI) et l'Université de Waterloo.

  17. Vulnérabilité et adaptation face aux changements climatiques et au ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Vulnérabilité et adaptation face aux changements climatiques et au VIH/sida en Afrique du Sud. Les changements climatiques et le VIH/sida sont largement reconnus comme des facteurs aggravants de la pauvreté chronique qui sévit en Afrique subsaharienne. Dans le cadre de ce projet, on cherchera à mieux comprendre ...

  18. Création d'un contexte concurrentiel et propice aux entreprises en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Création d'un contexte concurrentiel et propice aux entreprises en Cisjordanie et à Gaza. Certains facteurs - la durée indéterminée de l'occupation des ... governance in Palestine [Arabic language]. 45572. Papers. Impact of the draft company law on the performance of the private sector in Palestine [Arabic language].

  19. L'évaluation comme partie intégrante du processus d'adaptation aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    nbeaulieu

    Le programme Adaptation aux changements climatiques en Afrique (ACCA), une initiative conjointe du Département du Royaume Uni pour le développement international (DfID) et du. Centre de recherches pour le développement international (CRDI), met un accent important sur l'évaluation, et en particulier sur les ...

  20. Monitoring the performance of Aux. Feedwater Pump using Smart Sensing Model

    International Nuclear Information System (INIS)

    No, Young Gyu; Seong, Poong Hyun

    2015-01-01

    Many artificial intelligence (AI) techniques equipped with learning systems have recently been proposed to monitor sensors and components in NPPs. Therefore, the objective of this study is the development of an integrity evaluation method for safety critical components such as Aux. feedwater pump, high pressure safety injection (HPSI) pump, etc. using smart sensing models based on AI techniques. In this work, the smart sensing model is developed at first to predict the performance of Aux. feedwater pump by estimating flowrate using group method of data handing (GMDH) method. If the performance prediction is achieved by this feasibility study, the smart sensing model will be applied to development of the integrity evaluation method for safety critical components. Also, the proposed algorithm for the performance prediction is verified by comparison with the simulation data of the MARS code for station blackout (SBO) events. In this study, the smart sensing model for the prediction performance of Aux. feedwater pump has been developed. In order to develop the smart sensing model, the GMDH algorithm is employed. The GMDH algorithm is the way to find a function that can well express a dependent variable from independent variables. This method uses a data structure similar to that of multiple regression models. The proposed GMDH model can accurately predict the performance of Aux

  1. Neuf nouvelles subventions permettront d'améliorer l'accès aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    6 avr. 2017 ... ... nouvelles subventions permettront à neuf de ces équipes d'appliquer à grande échelle des interventions prometteuses et à combler le besoin d'information sur la planification familiale, de soutien aux mères adolescentes et de services et de renseignements en matière de santé sexuelle et reproductive.

  2. Prévalence et susceptibilité aux antibiotiques des souches de ...

    African Journals Online (AJOL)

    Prévalence et susceptibilité aux antibiotiques des souches de Salmonella spp. non typhiques isolées de la viande de poulets au Tchad. Hamadou Abba, Marius K. Somda, Ban-bo Bebanto Antipas, Nicolas Barro, Alfred S. Traore ...

  3. Les gagnants de la bourse du CRDI aux chercheurs candidats au ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les gagnants de la bourse du CRDI aux chercheurs candidats au doctorat de 2017. 30 novembre 2017. Cérémonie de certificat pour un programme de formation en entreprenariat en Ouganda, mai 2017. Michelle Savard. Michelle Savard, une récipiendaire de 2016, remet un certificat pour l'achèvement d'un programme ...

  4. Réduire les risques alimentaires associés aux maladies non ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Il permettra de générer de nouvelles connaissances sur le lien de causalité entre l'évolution des systèmes d'alimentation, pratiques alimentaires et tendances relatives aux maladies et les facteurs démographiques, épidémiologiques, socioculturels, économiques et comportementaux connexes. Les travaux de recherche ...

  5. Offrir un choix aux agriculteurs pauvres: Harsha de Silva (Sri Lanka ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ans de nombreux pays en développement, les téléphones mobiles permettent aux pauvres de profiter des avantages des technologies de l'information et de la communication (TIC). Des travaux de recherche appuyés par le CRDI et dirigés par Learning Initiatives on Reforms for Network Economies (LIRNEasia), ...

  6. De la recherche aux politiques - Établissement de liens entre l ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    La recherche sur les changements climatiques et leurs effets sur les populations vulnérables est assez avancée en Afrique australe. Toutefois, il y a peu de transfert des connaissances des scientifiques aux responsables des politiques. Ce projet vise à faciliter la traduction des résultats de la recherche en politiques de ...

  7. Le marche aux fetiches (lantassime) d'Akodessewa a Lome (Togo ...

    African Journals Online (AJOL)

    observation et les enquêtes par questionnaires a permis de montrer que le marché aux fétiches occupe des fonctions commerciale, sociale, cultuelle et mystique, économique et touristique. Il couvre une superficie de 1200 m² avec 15 stands sous ...

  8. Adapter les pratiques agricoles aux différentes conditions pédoclimatiques

    NARCIS (Netherlands)

    Turpin, N.; Perret, E.; Berge, ten H.F.M.; Hose, D' T.; Evert, van F.K.

    2016-01-01

    Les pratiques agricoles qui réduisent la quantité de carbone dans le sol peuvent perturber son activité microbienne, modifier sa structure, et sa capacité à fournir eau et nutriments aux cultures. Elles peuvent aussi limiter la capacité des sols agricoles à lutter contre le changement climatique. Le

  9. Moyens que prennent les collectivités pour faire face aux souvenirs ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Des années plus tard, les habitants de ces territoires sont toujours en proie aux traumatismes du passé. Cette recherche comparative analyse le processus de réparation en cours en Aceh et au Timor-Leste. Elle veut permettre de mieux comprendre comment les collectivités et les victimes individuelles de violations ...

  10. Isolation and characterization of an Aux/IAA gene ( LaIAA2 ) from Larix

    African Journals Online (AJOL)

    indole-3-acetic acid (Aux/IAA) transcriptional factors are key regulators of auxin responses in plants. To investigate the effects of auxin on gene expression during the rooting process of Larix cuttings, a subtractive cDNA library was constructed and ...

  11. Amélioration de la durée de conservation des bananes plantain aux ...

    African Journals Online (AJOL)

    Amélioration de la durée de conservation des bananes plantain aux températures ambiantes. A Lepengue, I Mouaragadja, E Dick, B Mbatchi, S Ake. Abstract. La banane plantain est le premier aliment de base au Gabon. Malheureusement 30 à 40% de sa production sont perdues, par manque de techniques de ...

  12. Peptidyl-prolyl isomerization targets rice Aux/IAAs for proteasomal degradation during auxin signalling.

    Science.gov (United States)

    Jing, Hongwei; Yang, Xiaolu; Zhang, Jian; Liu, Xuehui; Zheng, Huakun; Dong, Guojun; Nian, Jinqiang; Feng, Jian; Xia, Bin; Qian, Qian; Li, Jiayang; Zuo, Jianru

    2015-06-22

    In plants, auxin signalling is initiated by the auxin-promoted interaction between the auxin receptor TIR1, an E3 ubiquitin ligase, and the Aux/IAA transcriptional repressors, which are subsequently degraded by the proteasome. Gain-of-function mutations in the highly conserved domain II of Aux/IAAs abolish the TIR1-Aux/IAA interaction and thus cause an auxin-resistant phenotype. Here we show that peptidyl-prolyl isomerization of rice OsIAA11 catalysed by LATERAL ROOTLESS2 (LRT2), a cyclophilin-type peptidyl-prolyl cis/trans isomerase, directly regulates the stability of OsIAA11. NMR spectroscopy reveals that LRT2 efficiently catalyses the cis/trans isomerization of OsIAA11. The lrt2 mutation reduces OsTIR1-OsIAA11 interaction and consequently causes the accumulation of a higher level of OsIAA11 protein. Moreover, knockdown of the OsIAA11 expression partially rescues the lrt2 mutant phenotype in lateral root development. Together, these results illustrate cyclophilin-catalysed peptidyl-prolyl isomerization promotes Aux/IAA degradation, as a mechanism regulating auxin signalling.

  13. Réduire les risques et les pertes attribuables aux changements ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    examiner comment des villes comme Le Cap peuvent le mieux mettre en application des processus décisionnels efficaces dans le contexte de l'adaptation aux changements climatiques et d'un niveau élevé d'informalité.

  14. Etude comparative de la flore aux abords des cours d'eau dans les ...

    African Journals Online (AJOL)

    Etude comparative de la flore aux abords des cours d'eau dans les zones hypo et hyper endémiques d'ulcère de Buruli en Côte d'Ivoire. C. Cisse Boni, E. Ehouman, D. Soro, M.W. Kone, A. Bakayoko, F. Dembele, K. Bauthire, M Dosso ...

  15. Mise en place d'un réseau d'adaptation aux changements ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Ce projet a pour objectif de concevoir un mécanisme de gestion des risques accrus liés aux changements climatiques en appliquant le principe reconnu des ... Adaptation to Climate Change: Stakeholder engagement and understanding impacts - International Council for Local Environment Initiatives (ICLEI) (Section 21).

  16. Isolation and characterization of an Aux/IAA gene (LaIAA2) from Larix

    African Journals Online (AJOL)

    微软用户

    superfamily have been cloned from several species, includeing Arabidopsis thaliana, pea, Pisum sativum L., soybean, Glycine max (L.) Merrill, mung bean, Vigna radiata (L.) R. Wilcz, tobacco, cucumber, loblolly pine and tomato (Goldfarb et al., 2003; Zhang et al., 2007). The precise biochemical functions of Aux/IAA gene.

  17. EXAFS and FTIR studies of selenite and selenate sorption by alkoxide-free sol–gel generated Mg–Al–CO 3 layered double hydroxide with very labile interlayer anions

    KAUST Repository

    Chubar, Natalia

    2014-08-08

    © the Partner Organisations 2014. Current research on Layered Double Hydroxides (LDHs, also known as hydrotalcites, HTs) is predominantly focused on their intercalations, but the industrial application of LDHs for anion exchange adsorption has not yet been achieved. It was recently recognized that, to develop LDH applications, these materials should be produced using methods other than direct co-precipitation. Mg-Al-CO3LDH produced using an alkoxide-free sol-gel synthesis showed exceptional removal properties for aqueous selenium species. Se K-edge EXAFS/XANES and FTIR studies (supporting the data by XRD patterns) were performed to explain the unusual adsorptive performance of Mg-Al LDH by revealing the molecular-level mechanism of HSeO3 -, SeO4 2-and {HSeO3 -+ SeO4 2-} uptake at pH 5, 7 and 8.5. The role of inner-sphere complexation (exhibited by inorganic adsorbents with good performance) in adsorption of both selenium aqueous species was not confirmed. However, Mg-Al LDH fully met the other expectations regarding the involvement of the interlayer anions. The interlayer carbonate (due to its favorable speciation and generous HT hydration) gave a "second breath" to selenite sorption and was the only mechanism that controlled the removal of Se(vi). Because inner sphere complexation was the leading mechanism for selenite removal, ion exchange via surface OH-and interlayer CO3 2-species was the only mechanism for selenate removal; both of these species were easily bound to Mg-Al LDH (on its surface and gently parked into the interlayer forming a multilayer without violation of the structure of Mg-Al-CO3LDH). This work provides the first theoretical explanation of why it is more difficult to sorb selenate than selenite and which material should be used for this purpose. This journal is

  18. Genome-wide analysis of Aux/IAA and ARF gene families in Populus trichocarpa

    Energy Technology Data Exchange (ETDEWEB)

    Kalluri, Udaya C [ORNL; DiFazio, Stephen P [West Virginia University; Brunner, A. [Virginia Polytechnic Institute and State University (Virginia Tech); Tuskan, Gerald A [ORNL

    2007-01-01

    Auxin/Indole-3-Acetic Acid (Aux/IAA) and Auxin Response Factor (ARF) transcription factors are key regulators of auxin responses in plants. A total of 35 Aux/IAA and 39 ARF genes were identified in the Populus genome. Comparative phylogenetic analysis revealed that the subgroups PoptrARF2, 6, 9 and 16 and PoptrIAA3, 16, 27 and 29 have differentially expanded in Populus relative to Arabidopsis. Activator ARFs were found to be two fold-overrepresented in the Populus genome. PoptrIAA and PoptrARF gene families appear to have expanded due to high segmental and low tandem duplication events. Furthermore, expression studies showed that genes in the expanded PoptrIAA3 subgroup display differential expression. The gene-family analysis reported here will be useful in conducting future functional genomics studies to understand how the molecular roles of these large gene families translate into a diversity of biologically meaningful auxin effects.

  19. Le Carnaval de Schignano : un dernier salut aux émigrants

    Directory of Open Access Journals (Sweden)

    Cristina Del Biaggio

    2011-05-01

    Full Text Available Pour arriver à Schignano, il faut passer par una cürva al giazz e una cürva al suu [Un virage dans la glace et un virage au soleil], comme disent les mots en dialecte d’une récente chanson écrite par Davide Van De Sfroos, compositeur-interprète de la région. C’est dans ce petit hameau de la Vallée d’Intelvi, au-dessus du Lac de Côme, que, tous les ans, le carnaval anime le village. Une fête populaire spontanée, sans règles écrites, ni lois, qui survit grâce aux habitants qui l’animent, aux ar...

  20. L’orthographe : des systèmes aux usages

    OpenAIRE

    Fayol, Michel; Jaffré, Jean-Pierre

    2016-01-01

    Ce texte propose un éclairage à la fois linguistique et psycholinguistique sur l’orthographe. Au-delà de la spécificité inhérente, par définition, aux deux domaines, il illustre la complémentarité épistémologique qui s’est développée entre eux au cours des dernières décennies. La psycholinguistique a très souvent fait appel aux descriptions linguistiques pour élaborer ses hypothèses de travail et, de son côté, la linguistique s’est inspirée à maintes reprises des observations psycholinguistiq...

  1. Soutien à la recherche économique et sociale aux fins de la ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Le nouveau site Web facilitera l'enregistrement des événements démographiques afin d'améliorer l'accès aux services pour tous. Le nouveau site Web et la nouvelle bibliothèque de ressources aideront à améliorer les systèmes d'information et d'enregistrement des faits d'état civil dans les pays en développement.

  2. Accès aux TIC et leur utilisation en enseignement supérieur en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les politiques dans le domaine de l'enseignement supérieur en matière de technologies de l'information et de la communication (TIC) présument qu'un accès accru aux TIC encourage leur utilisation. Une première collecte de données effectuée en 2004 et 2007 fournit une base des plus nécessaires sur laquelle fonder la ...

  3. Adaptation des politiques de pêche aux changements climatiques à ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Adaptation des politiques de pêche aux changements climatiques à l'aide des savoirs scientifiques et de connaissances endogènes (Afrique de l'Ouest). Le secteur de la pêche ressente les changements climatiques de différents manières, soit dans la composition des populations animales et végétales, dans des ...

  4. Justice sociale face aux mariages précoces en Afrique de l'Ouest ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Justice sociale face aux mariages précoces en Afrique de l'Ouest. Au Sénégal et en Côte d'Ivoire, les statistiques courantes montrent un relèvement de l'âge moyen du premier mariage des filles à plus de 18 ans. Cependant, l'évaluation des programmes de lutte contre ces phénomènes dans ces pays ont montré que ces ...

  5. Réduire les risques et les pertes attribuables aux changements ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    22 août 2014 ... Entre-temps, dans les pays plus riches, comme le Japon et les États‑Unis, les bâtiments et l'infrastructure font l'objet de nouvelles conceptions visant à prévenir les conséquences des tremblements de terre. Quelle comparaison feriez‑vous entre les plans d'adaptation aux tremblements de terre et les ...

  6. Aux/IAA gene family is conserved in the gymnosperm, loblolly pine (Pinus taeda).

    Science.gov (United States)

    Goldfarb, Barry; Lanz-Garcia, Carmen; Lian, Zhigang; Whetten, Ross

    2003-12-01

    We isolated five members of the Aux/IAA gene family in loblolly pine (Pinus taeda L.). Degenerate primers complementary to conserved regions of angiosperm Aux/IAA genes were used to amplify fragments that were, in turn, used as probes to screen a cDNA library constructed from auxin-treated hypocotyls. The five unique clones, named PTIAA1-5, contain the four highly conserved domains that are characteristic of the Aux/IAA proteins. All clones contain the bipartite nuclear localization signal (NLS) between Domains I and II that is predicted in most angiosperm Aux/IAA genes, but only one, PTIAA2, contains the conserved NLS in Domain IV. The five invariant residues in Domain II that have been found to constitute part of a protein destabilization element in Arabidopsis thaliana (L.) Heynh. are conserved in all the PTIAAs. A postulated phosphorylation site located between Domains I and II and proximal to the conserved bipartite NLS was conserved in 20 out of 36 genes in this analysis, including the pine genes. Transcripts of all five PTIAAs accumulated specifically in the hypocotyls in response to exogenous auxin treatment and were induced by all auxins tested. Transcript abundance above basal levels in response to 1-naphthaleneacetic acid treatment was first detected after 10 min (PTIAA3) to 3 h (PTIAA2) in the different genes and remained above basal levels throughout 7 days. Induction of PTIAA2 was inhibited by the protein synthesis inhibitor cycloheximide, indicating that PTIAA2 is a secondary response gene. Phylogenetic analysis showed that all five pine genes clustered within a single class (Class I) of the dendrogram. Clone PTIAA2 has a sequence that is relatively distinct from the other four and is the most closely related to the angiosperm genes of Class I. Class I contains both primary and secondary auxin response genes, suggesting that it is the original lineage and that other gene classes have evolved subsequent to the angiosperm/gymnosperm divergence.

  7. Communiquer les risques associés au climat aux collectivités ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    13 mai 2015 ... Le Vietnam est particulièrement vulnérable aux changements climatiques et à la hausse du niveau des océans qui en découle, puisqu'une partie importante de sa population vit dans les basses terres des deltas et le long de la côte, des zones à haut risque. En 2011, d'importantes inondations ont ...

  8. ÉTUDE DE CAS — Philippines : Aux Philippines, les progrès ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    17 déc. 2010 ... Aux Philippines, le système de suivi communautaire de la pauvreté, d'abord projet pilote, s'est étendu, en 14 ans, à l'échelle nationale, appuyé par tous les ordres de gouvernement. Les données orientent la planification et le ciblage des programmes, les affectations budgétaires, ainsi que le suivi des ...

  9. Adaptation aux effets qu'ont les changements climatiques sur les ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Le projet a pour objectif général d'appuyer la capacité d'adaptation aux effets que les changements climatiques ont sur les ressources en eau au Canada, ... de transfert et d'application des connaissances ayant trait à la salubrité du climat et à la gestion des risques que les changements climatiques présentent pour la ...

  10. Point saillant : Des scientifiques répondent aux défis du changement ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Plus de 2 200 scientifiques et chercheurs de premier plan ont participé à la conférence scientifique Notre avenir commun sous le changement climatique qui s'est déroulée à Paris, en France, en juillet. La conférence s'est attardée aux grandes questions liées au climat en amont de la 21e Conférence des parties de la ...

  11. Suspicion de la résistance aux benzimidazoles chez les strongles ...

    African Journals Online (AJOL)

    Suspicion de la résistance aux benzimidazoles chez les strongles gastrointestinaux du caprin à Lubumbashi, R.D. Congo. EV Okombe, SEW Pongombo. Abstract. Cent vingt-quatre caprins sélectionnés dans deux fermes de la région de Lubumbashi en R.D. Congo, ont été examinés en utilisant le test de réduction de ...

  12. Vulnérabilité et adaptation aux changements climatiques des ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    21 avr. 2016 ... Madagascar, la quatrième plus grande île au monde, héberge une multitude de formes de vie qu'on ne trouve nulle part ailleurs sur la planète. Dans la plupart des cas, cette biodiversité est extrêmement vulnérable aux changements climatiques, tout comme l'agriculture pluviale, la pêche et la foresterie, ...

  13. Solutions de remplacement à la culture du tabac et aux activités ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Solutions de remplacement à la culture du tabac et aux activités connexes (Inde) ... L'Inde fait toutefois partie du groupe de travail sur les activités de remplacement de la culture du tabac économiquement viables de l'Organisation mondiale de la santé (OMS) et dispose de ... India, Central Asia, Far East Asia, South Asia ...

  14. Adaptation à la variabilité du climat et aux changements climatiques ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    25 avr. 2014 ... En même temps, selon les prévisions, les changements climatiques entraîneront une hausse des températures et une baisse des précipitations. Étant donné le rôle de la région dans l'économie chilienne, une stratégie d'adaptation aux changements climatiques s'impose de toute urgence. Wine production ...

  15. La vulnérabilité aux changements climatiques, une expérience ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    21 avr. 2011 ... Madagascar, la quatrième plus grande île au monde, héberge une multitude de formes de vie qu'on ne trouve nulle part ailleurs sur la planète. Dans la plupart des cas, cette biodiversité est extrêmement vulnérable aux changements climatiques, tout comme l'agriculture pluviale, la pêche et la foresterie, ...

  16. Amélioration de l'adaptation aux changements climatiques des ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Amélioration de l'adaptation aux changements climatiques des pasteurs du nord du Kenya. Près de 13 % des 30 millions d'habitants du Kenya sont des pasteurs dont les troupeaux vivent dans des terres arides et semi-arides qui composent environ 75 % de la masse terrestre du pays. Ces régions sont sujettes à une ...

  17. Adaptation aux changements climatiques dans la vallée de Mantaro ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les inondations dues aux phénomènes météorologiques extrêmes causent de plus en plus de ravages le long du río de la Plata en Argentine et en Uruguay. Des chercheurs subventionnés par le CRDI ont constaté que le changement des conditions météorologiques et l'intensité des phénomènes météorologique.

  18. Accès des femmes aux terres : appel à propositions | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Accès des femmes aux terres : appel à propositions. Ce projet est né du besoin de mieux comprendre, au-delà du cadre juridique, les obstacles que doivent surmonter les femmes qui veulent accéder à la propriété foncière ou à d'autres ressources de production. En 2005, le CRDI a apporté son soutien à quelques études ...

  19. 211 Vulnérabilité des troupeaux transhumants aux mutations ...

    African Journals Online (AJOL)

    ZAKARI SOUF

    L'économie locale est dominée par l'agriculture, l'élevage et la pêche qui emploient l'essentiel de la population active. Les principales productions ...... du W (Bénin), Mémoire de Diplôme d'Etudes Approfondies, FSA/UAC, (2011), 100 p. [7] - S. N. I. Djenontin, Vulnérabilité des ressources en eau face aux changements ...

  20. Moyens que prennent les collectivités pour faire face aux souvenirs ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Moyens que prennent les collectivités pour faire face aux souvenirs traumatiques - enseignements tirés d'Aceh et du Timor-Leste. La province d'Aceh et l'État maintenant indépendant du Timor-Leste (auparavant le Timor oriental) ont vécu des décennies de conflit et des violations massives des droits de la personne sous la ...

  1. Gestion de la biodiversité agricole aux fins de la nutrition, de la ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les qualités nutritionnelles des aliments provenant des systèmes de production alimentaire de l'Afrique se dégradent, comme l'indiquent la prévalence accrue de carences en micronutriments et de maladies chroniques et la faible résistance aux maladies infectieuses. En s'appuyant sur les expériences antérieures dans ...

  2. Le CRDI aide l'Inde à s'adapter aux changements climatiques au ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    23 févr. 2018 ... Plans d'action sur l'adaptation aux changements climatiques pour gérer le stress thermique dans les villes indiennes (Integrated Research and Action for Development, 1 001 800 $). Le projet vise à améliorer la gestion des risques associés au stress thermique en Inde grâce à l'élaboration de plans ...

  3. Des bananes plus nutritives et qui résistent aux maladies | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    28 oct. 2010 ... Les petits agriculteurs jouissent de meilleurs revenus et d'une sécurité alimentaire accrue grâce à des variétés de bananes à haut rendement qui résistent aux maladies. Au cours des années 1980 et 1990, avec le soutien du CRDI, la Fundación Hondureña de Investigación Agricola (FHIA) a mis au point ...

  4. Renforcement de la résilience aux changements climatiques pour ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    29 sept. 2016 ... Les chercheurs de Cenicafé bénéficieront également de l'aide du personnel du Partenariat de café de Tim Hortons, un programme de soutien aux cultivateurs mis sur pied par Tim Hortons en 2005 en vue d'améliorer les activités et les conditions de vie des caféiculteurs. Le groupe travaillera dans deux ...

  5. Liste de vérification Bourse du CRDI aux chercheurs candidats au ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Vous ne pouvez présenter une demande que deux fois pour ce concours du CRDI, et ce, pour deux années consécutives. Si une bourse ne vous a pas été accordée lors de l'appel de la Bourse du CRDI aux chercheurs candidats au doctorat de mai 2016 et que vous envisagez de présenter une demande une deuxième ...

  6. Renforcement des droits fonciers communautaires et réactions aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    De telles menaces qui planent sur les droits fonciers et environnementaux des collectivités sont un indice de tensions plus grandes au sein de l'appareil d'État et du système de justice. Dans ce ... Des droits internationaux aux pratiques locales : la réforme constitutionnelle et la participation en Amérique latine. Ce projet ...

  7. Evaluation in vitro de la sensibilité de Pythium aphanidermatum aux ...

    African Journals Online (AJOL)

    La pourriture des racines et du collet du papayer en Côte d'Ivoire sévit dans les plantations, causant des pertes énormes. Cependant, malgré les traitements fongiques, la maladie persiste. L'objectif de cette étude est de tester in vitro la sensibilité de Pythium aphanidermatum, responsable de la maladie, aux fongicides ...

  8. L'arbre des problèmes, des racines jusqu'aux ramilles | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    7 janv. 2011 ... Après avoir utilisé l'« arbre de problèmes », les Katkari ont eu recours à d'autres outils offerts par les SAS², tels que la dynamique causale et l'analyse des parties prenantes, pour déterminer s'il convenait de porter leur cause devant les autorités gouvernementales. Ces outils ont permis aux Katkari de ...

  9. Des services en santé mentale accessibles aux Kényans vivant en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    15 juil. 2013 ... Ces principes sont applicables non seulement au Kenya, mais aussi à d'autres pays à faible revenu qui souhaitent améliorer l'accès aux services en santé mentale. Cet article a été rédigé par Esmé Lanktree, agente de gestion de programme à l'IRSM, et révisé par Gyde Shepherd et Marie-Danielle Smith.

  10. Comportement expérimental aux cisaillements roulant et de voile de ...

    African Journals Online (AJOL)

    dans le sens de la longueur du panneau (L) et pour moitié dans le sens perpendiculaire ou transversal (T) en utilisant deux dispositifs ... Le sens de la découpe influe peu sur la résistance au cisaillement laquelle montre une augmentation avec .... L'objectif de ce travail est de déterminer la résistance aux cisaillements ...

  11. Offrir un choix aux agriculteurs pauvres: Harsha de Silva (Sri Lanka ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Nos travaux sont vraiment à la fine pointe, en ce sens qu'ils visent à offrir des choix aux agriculteurs, à les rendre plus autonomes grâce au téléphone mobile. Nous venons d'achever une étude exhaustive sur l'utilisation que font des TIC 10 000 personnes pauvres au Pakistan, en Inde, au Sri Lanka, au Bangladesh, ...

  12. Un partenariat pour lutter contre la résistance aux antimicrobiens ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    11 avr. 2018 ... Le CRDI et le Global AMR Innovation Fund du Royaume-Uni, qui sera géré par le Department of Health and Social Care (DHSC) du Royaume-Uni, rentre dans un nouveau partenariat pour une nouvelle initiative dont l'objectif est de réduire les risques émergents que pose la résistance aux antimicrobiens ...

  13. Le Sri Lanka mieux préparé aux futurs tsunamis | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    9 nov. 2012 ... Les collectivités côtières vulnérables du Sri Lanka sont désormais mieux outillées pour survivre aux tsunamis, cyclones et autres catastrophes naturelles survenant soudainement. Ce degré accru de préparation est le fruit de travaux de recherche financés par le CRDI qui visaient à cerner les meilleurs ...

  14. Mobiliser les investissements du secteur privé dans l'adaptation aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Cette recherche vise à examiner divers moyens d'élargir le champ des options disponibles pour inciter le secteur privé à investir dans l'adaptation aux changements climatiques. Elle étudiera aussi diverses possibilités d'exploiter le financement privé pour appliquer à plus grande échelle les efforts d'adaptation dans les ...

  15. Financement de base du Rimisp aux fins de la recherche pour le ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Financement de base du Rimisp aux fins de la recherche pour le développement rural (Amérique latine et Caraïbes). Il est urgent que l'Amérique latine mette en place des politiques qui favorisent une dynamique rurale contribuant à la croissance économique, à l'inclusion sociale et à une saine gouvernance de ...

  16. Impact des prestations de l'agence pour la promotion et l'appui aux ...

    African Journals Online (AJOL)

    Leurs dépenses sociales ou investissements sur le capital humain (santé, éducation, alimentation, cérémonies diverses, etc.) sont donc améliorées grâce à PAPME. Sans l'accès au micro crédit et aux services financiers, les petites et micro entreprises ne pourront pas faire des investissements qui créent et soutiennent les ...

  17. Au-delà de l'accès : Donner la première place aux femmes en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2 sept. 2017 ... Nous savons, par exemple, que si les femmes avaient accès aux mêmes ressources de production, comme les engrais, les machines et la documentation que les hommes, elles pourraient améliorer le rendement de leurs fermes de 20 à 30 pour 100. Mais combler les écarts en ce qui concerne l'accès aux ...

  18. Étude sur l'escalade de la violence faite aux femmes en Amérique ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Étude sur l'escalade de la violence faite aux femmes en Amérique centrale. 21 juin 2016. Ana Carcedo. En Amérique centrale, on assiste à une escalade de la violence faite aux femmes et du nombre de meurtres de femmes (ou femicides). Or, il y a des lacunes sur le plan du signalement. Primo, malgré les efforts déployés ...

  19. Amélioration de l'accès à la justice et aux services essentiels dans ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Plus de la moitié des résidents de Nairobi, au Kenya, occupent des établissements spontanés, ou bidonvilles, dans des conditions difficiles. Leurs logements sont inadéquats et ils ont un accès insuffisant à l'eau potable, aux services d'assainissement, aux services de santé, à l'école et à d'autres services publics essentiels ...

  20. Ne réduisez pas les programmes destinés aux femmes. Intégrez-les ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    27 juil. 2017 ... Au cours des derniers mois, nous avons entendu dire que l'administration Trump a prévu de réduire le financement de plusieurs programmes s'adressant aux femmes, comme le Bureau des affaires mondiales relatives aux femmes du département d'État. Ce n'est pas le seul programme. Une évaluation ...

  1. Synthesis and crystal structure of a new neodymium(III) selenate-selenite: Nd2(SeO4)(SeO3)2(H2O)2

    International Nuclear Information System (INIS)

    Feng Meiling; Mao Jianggao

    2005-01-01

    The title new neodymium(III) selenate-selenite was obtained by hydrothermal reactions of neodymium(III) oxide, H 2 SeO 4 and 1,10-phenanthroline at 140 o C. Its structure was established by single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic space group C2/c with cell parameters of a = 12.258(2) A, b 7.1024(15) A, c = 13.391(3) A, β = 104.250(2) o . The structure of Nd 2 (SeO 4 )(SeO 3 ) 2 (H 2 O) 2 is isomorphous with that of Er 2 (SeO 4 )(SeO 3 ) 2 (H 2 O) 2 , which was refined in the monoclinic space group C2 with the disordered selenate group. It features an ordered 3D network with channels along b-axis. The selenate or selenite groups alone can form a 2D layer with the Nd(III) ions. IR spectrum, TGA and luminescent studies have also been performed

  2. The synthesis and crystal structures of the first rare-earth alkaline-earth selenite chlorides MNd10(SeO3)12Cl8 (M=Ca and Sr)

    International Nuclear Information System (INIS)

    Berdonosov, P.S.; Olenev, A.V.; Dolgikh, V.A.; Lightfoot, P.

    2007-01-01

    Two new alkaline-earth Nd selenite chlorides MNd 10 (SeO 3 ) 12 Cl 8 (M=Ca, Sr) were obtained using crystal growth from alkaline-earth chloride melts in quartz tubes. These new compounds crystallize in the orthorhombic system in space group C cca (no. 68). The compounds were studied by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction. It was shown that both compounds adopt the same structure type, constructed by complex [M 11 (SeO 3 ) 12 ] 8+ slabs separated by chloride anion layers perpendicular to the longest cell parameter. The SeO 3 groups show a pyramidal shape and may be described as SeO 3 E tetrahedra. Such SeO 3 groups decorate the Nd-O skeletons forming the [M 11 (SeO 3 ) 12 ] 8+ slabs. - Graphical abstract: Two new alkaline-earth Nd selenite chlorides MNd 10 (SeO 3 ) 12 Cl 8 (M=Ca, Sr) were synthesized. These structures are constructed by [M 11 (SeO 3 ) 12 ] 8+ slabs separated by chloride anion layers

  3. Développement d'immunoessais associés aux électrodes sérigraphiées: des particules superparamagnétiques aux nanobodies

    OpenAIRE

    Patris, Stéphanie

    2014-01-01

    Cette thèse a pour vocation de contribuer au développement de différents immunocapteurs ampérométriques associés aux électrodes sérigraphiées (SPE). Les immunocapteurs sont des dispositifs simples associant un anticorps ou un antigène qui assurent la sélectivité à un transducteur (ici une SPE) ;ce dernier transforme la liaison anticorps/antigène en un signal mesurable (ici ampérométrique).Le travail est divisé en deux volets principaux.Le premier est consacré à la mise en œuvre de différents ...

  4. Développement d'immunoessais associés aux électrodes sérigraphies: des particules superparamagnétiques aux nanobodies

    OpenAIRE

    Patris, Stéphanie

    2014-01-01

    Cette thèse a pour vocation de contribuer au développement de différents immunocapteurs ampérométriques associés aux électrodes sérigraphiées (SPE). Les immunocapteurs sont des dispositifs simples associant un anticorps ou un antigène qui assurent la sélectivité à un transducteur (ici une SPE) ;ce dernier transforme la liaison anticorps/antigène en un signal mesurable (ici ampérométrique). Le travail est divisé en deux volets principaux. Le premier est consacré à la mise en œuvre de dif...

  5. Evaluation du procédé d'abattage des bovins aux abattoirs de ...

    African Journals Online (AJOL)

    La viande est une denrée alimentaire hautement périssable dont la qualité hygiénique dépend de la contamination pendant les opérations d'abattage et de découpe. L'objectif de l'étude est d'évaluer le procédé d'abattage des bovins aux abattoirs de Cotonou-Porto-Novo au sud-Bénin. L'analyse du procédé d'abattage a ...

  6. Methodes spectrales paralleles et applications aux simulations de couches de melange compressibles

    OpenAIRE

    Male , Jean-Michel; Fezoui , Loula ,

    1993-01-01

    La resolution des equations de Navier-Stokes en methodes spectrales pour des ecoulements compressibles peut etre assez gourmande en temps de calcul. On etudie donc ici la parallelisation d'un tel algorithme et son implantation sur une machine massivement parallele, la connection-machine CM-2. La methode spectrale s'adapte bien aux exigences du parallelisme massif, mais l'un des outils de base de cette methode, la transformee de Fourier rapide (lorsqu'elle doit etre appliquee sur les deux dime...

  7. Mortalite liee au VIH chez les enfants aux Chu campus et tokoin de ...

    African Journals Online (AJOL)

    Introduction. Le but de ce travail était d'étudier la mortalité liée au VIH chez les enfants séropositifs aux CHU-Campus et Tokoin de Lomé. Patients et méthode. Il s'est agi d'une étude prospective qui s'est déroulée dans les services de pédiatrie des CHU-Campus et Tokoin de Lomé et qui a couvert une période de 6 mois ...

  8. Perception des risques liés aux changements climatiques dans les ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    4 sept. 2014 ... L'équipe du projet Perception du risque et vulnérabilité des milieux humides sur la côte atlantique de l'Amérique du Sud, qui a commencé en 2012, privilégie une démarche de gestion intégrée des zones côtières et s'appuie sur les perceptions que les parties prenantes ont des risques liés aux ...

  9. Alternatives to Anti-Personnel Landmines (Solutions de remplacement aux mines antipersonnel)

    Science.gov (United States)

    2003-05-01

    remplacement ont un prix : elles sont plus pesantes sur le plan logistique et impliquent des risques opérationnels pour les forces de l’OTAN. En...très importante, de l’interopérabilité dans le transfert de secteurs qui ont été minés par un pays non-signataire de la Convention d’Ottawa. Le...SEINE CEDEX, FRANCE RTO TECHNICAL REPORT 40(I) Alternatives to Anti-Personnel Landmines (Solutions de remplacement aux mines antipersonnel) Military

  10. William Dab, Danielle Salomon, Agir face aux risques sanitaires. Pour un pacte de confiance

    OpenAIRE

    Vieira Bertho, Isabela

    2016-01-01

    Écrit à deux mains, « Agir face aux risques sanitaires » présente une réflexion sur la gestion actuelle des risques sanitaires en France. Les auteurs William Dab, ancien directeur général de la santé en France et actuel directeur de l’École des sciences industrielles et technologies de l’information au Conservatoire national des arts et métiers (CNAM) et Danielle Salomon, sociologue des organisations et des risques, offrent dans ce livre une analyse de la politique sécuritaire sanitaire franç...

  11. Vulnérabilité des troupeaux transhumants aux mutations climatiques ...

    African Journals Online (AJOL)

    L'élevage bovin occupe une place importante parmi les activités des populations du Nord-Est du Bénin. Cette activité est très vulnérable aux mutations climatiques dans le bassin de la Sota à Malanville situé à l'extrême Nord-Est du Bénin. La présente recherche vise, d'une part, à appréhender, les perceptions des ...

  12. Conference - Découvrez notre région - Aux bornes de Genève

    CERN Multimedia

    Staff Association

    2016-01-01

      Les premières bornes-frontière sont posées en 1816 aux confins du royaume de Sardaigne, d’autres feront leur apparition dès 1818 du côté du royaume de France. Deux cents ans plus tard, on retrouve toujours ces pierres, témoins de la naissance du canton et patrimoine partagé des communes genevoises, gessiennes et savoisiennes qui font notre région.  

  13. Vibrational and Thermal Properties of Oxyanionic Crystals

    Science.gov (United States)

    Korabel'nikov, D. V.

    2018-03-01

    The vibrational and thermal properties of dolomite and alkali chlorates and perchlorates were studied in the gradient approximation of density functional theory using the method of a linear combination of atomic orbitals (LCAO). Long-wave vibration frequencies, IR and Raman spectra, and mode Gruneisen parameters were calculated. Equation-of-state parameters, thermodynamic potentials, entropy, heat capacity, and thermal expansion coefficient were also determined. The thermal expansion coefficient of dolomite was established to be much lower than for chlorates and perchlorates. The temperature dependence of the heat capacity at T > 200 K was shown to be generally governed by intramolecular vibrations.

  14. Les représentations sociales du travail dans des parcours de retour aux études aux niveaux collégial et universitaire

    Directory of Open Access Journals (Sweden)

    Claude Julie Bourque

    2009-10-01

    Full Text Available Cet article porte sur le volet éducatif de la production et de la reproduction de la main-d’œuvre hautement qualifiée par l’examen des processus en jeu au moment des retours aux études dans des programmes de formation technique et de génie. Nous nous intéressons en particulier à une situation emblématique des référentiels politiques récents en matière d’éducation, soit les retours aux études. Nous cherchons à mieux comprendre comment le retour aux études se réalise, comment les représentations professionnelles agissent sur ce dernier et comment l’expérience scolaire influence les projets des individus. Notre analyse met l’accent sur les ressorts sociaux et culturels des décisions relatives au choix de programmes et à l’orientation professionnelle d’étudiants qui ont interrompu leurs études et qui y retournent. Nous explorons le discours d’étudiants et d’étudiantes qui ont choisi de profiter de la souplesse du système d’éducation québécois pour compléter ou bonifier leur formation initiale ou encore pour tenter une réorientation professionnelle. En particulier, nous désirons savoir comment les différentes formes d’articulation entre éducation et travail influencent les représentations sociales des étudiants au sujet des titres scolaires, de l’évolution de leur carrière scolaire et de leur projet professionnel personnel.This paper deals with the educational aspect of the production and reproduction of highly qualified manpower through examining the processes at play when people return to school by enrolling in technical or engineering training programs. Our interest is focussed specifically on returning to school as an emblematic situation in recent educational policy frameworks. We are trying to better understand how school return is done, how professional representations act upon it and how previous school experience influences individual projects. Our analysis focuses on the

  15. Edgar Morin, aux risques d'une pensée libre

    CERN Document Server

    Pena Vega, Alfredo

    2011-01-01

    8 juillet 2011 ; Edgar Morin fête ses 90 ans et 60 ans passés au sein du CNRS. Une occasion unique pour l'équipe d'Hermès et Dominique Wolton, d'analyser et de critiquer la pensée de ce grand intellectuel. Aspiration à la liberté, attention à la complexité du monde et une profonde originalité épistémologique, Edgar Morin a bouleversé aussi bien la philosophie, la politique que la physique ou les mathématiques. Avec un souci constant : faire communiquer et interagir toutes les sciences pour relever le défi de la compréhension. Plus qu'un simple hommage, ce numéro questionne l'œuvre d'Edgar Morin au filtre de la communication, dévoilant les mécaniques de cette vision du monde profondément originale, échappant aux cloisonnements et aux certitudes académiques, portée par un projet central, celui d'une réforme des connaissances. Suivant les cheminements intellectuels et politiques de ce chercheur itinérant et passionné à travers l'Europe, l'Est, l'Amérique latine ou les États-Unis, ce...

  16. Aux cartes citoyens. La démocratie par les cartes

    Directory of Open Access Journals (Sweden)

    Anne Chapuis

    2000-11-01

    Full Text Available Les cartes, images puissantes rendant visible et compréhensibles des informations nombreuses et complexes, ont une vocation naturelle à servir de support aux débats sur l'aménagement du territoire et aux actions de développement, et en cela être un des outils privilégiés de la démocratie. Plusieurs expériences au sein de collectivités territoriales en France et au sein d'organismes de développement en Inde nous ont démontré que l'utilisation de cartes et matrices pour l'aide à la décision est le plus souvent jugée dangereuse. Bien construites elles sont révélatrices des déséquilibres spatiaux, des enjeux de pouvoir et bien entendu de la corruption. Nous présentons quelques unes de ces expériences avec en arrière plan les enjeux de la démocratie et de la Transparence tant vantées et si peu pratiquées.

  17. Safety Training: Sensibilisation aux gestes et postures de travail

    CERN Multimedia

    Laetitia Laddada

    2004-01-01

    Nous vous proposons un nouveau cours de sécurité lié aux manutentions manuelles (durée 1 jour) : Sensibilisation aux gestes et postures de travail. Si vous êtes amené à manipuler régulièrement des charges lourdes ou volumineuses, cette formation peut vous aider à prévenir les lésions musculaires ou dorsales. A l'issue de cette formation, vous serez capable d'adopter et d'appliquer les principes de base de sécurité physique et d'économie d'efforts dans les manipulations d'objets. Les cours sont pris en charge par la Commission de Sécurité. L'inscription EDH est obligatoire. Pour plus d'information, veuillez consulter les pages Formation & Développement (Groupe Sécurité). Formation & Développement (Groupe Sécurité) FORMATION EN SECURITE SAFETY TRAINING Laetitia Laddada 73811 - 79236 sa...

  18. Safety Training: Sensibilisation aux gestes et postures de travail

    CERN Multimedia

    Laetitia Laddada

    2004-01-01

    >Nous vous proposons un nouveau cours de sécurité lié aux manutentions manuelles (durée 1 jour) : Sensibilisation aux gestes et postures de travail. Si vous êtes amené à manipuler régulièrement des charges lourdes ou volumineuses, cette formation peut vous aider à prévenir les lésions musculaires ou dorsales. A l'issue de cette formation, vous serez capable d'adopter et d'appliquer les principes de base de sécurité physique et d'économie d'efforts dans les manipulations d'objets. Les cours sont pris en charge par la Commission de Sécurité. L'inscription EDH est obligatoire. Pour plus d'information, veuillez consulter les pages Formation & Développement (Groupe Sécurité). Formation & Développement (Groupe Sécurité) FORMATION EN SECURITE SAFETY TRAINING Laetitia Laddada 73811 - 79236 s...

  19. Safety Training: Sensibilisation aux gestes et postures de travail

    CERN Multimedia

    Laetitia Laddada

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. Nous vous proposons un nouveau cours de sécurité lié aux manutentions manuelles (durée 1 jour) : Sensibilisation aux gestes et postures de travail. Si vous êtes amené à manipuler régulièrement des charges lourdes ou volumineuses, cette formation peut vous aider à prévenir les lésions musculaires ou dorsales. A l'issue de cette formation, vous serez capable d'adopter et d'appliquer les principes de base de sécurité physique et d'économie d'efforts dans les manipulations...

  20. Safety Training: Sensibilisation aux gestes et postures de travail

    CERN Multimedia

    Laetitia Laddada

    2004-01-01

    Nous vous proposons un nouveau cours de sécurité lié aux manutentions manuelles (durée 1 jour) : Sensibilisation aux gestes et postures de travail. Si vous êtes amené à manipuler régulièrement des charges lourdes ou volumineuses, cette formation peut vous aider à prévenir les lésions musculaires ou dorsales. A l'issue de cette formation, vous serez capable d'adopter et d'appliquer les principes de base de sécurité physique et d'économie d'efforts dans les manipulations d'objets. Les cours sont pris en charge par la Commission de Sécurité. L'inscription EDH est obligatoire. Pour plus d'information, veuillez consulter les pages Formation & Développement (Groupe Sécurité). Formation & Développement (Groupe Sécurité) FORMATION EN SECURITE SAFETY TRAINING Laetitia Laddada 73811 - 79236 safety.training@cern.ch

  1. Nd3(SeO3)4OH: the first rare earth hydroxide selenite with the Gd3(SeO3)4F-type structure

    International Nuclear Information System (INIS)

    Dityat'ev, O. A.; Berdonosov, P. S.; Olenev, A. V.; Dolgikh, V. A.

    2005-01-01

    Monocrystals of a new neodymium hydroxide selenite Nd 3 (SeO 3 ) 4 OH are prepared by hydrothermal synthesis and studied by X-ray diffraction. The compound is found to crystallize in space group P6 3 mc with the unit cell parameters: a = 10.547(1) A, c = 7.134(1) A, Z = 2. The Nd 3 (SeO 3 ) 4 OH structure contains a three-dimensional framework of chains consisting of NdO 9 polyhedra. Selenium(IV) atoms, whose environment includes three oxygen atoms each, are arranged along voids of the framework. The Nd 3 (SeO 3 ) 4 OH structure is isotypical to Gd 3 (SeO 3 ) 4 F. The hydroxide oxygen atom in the new structure plays the role of the F atom in Gd 3 (SeO 3 ) 4 F [ru

  2. De la forêt aux champs en Côte d'Ivoire | CRDI - Centre de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    3 févr. 2011 ... Aujourd'hui, Buyo fait partie de la « nouvelle ceinture du café et du cacao » de la Côte d'Ivoire et est devenu un pôle d'attraction pour les immigrants économiques. La plupart y viennent en quête de terres où s'adonner aux cultures marchandes destinées à l'exportation ou aux marchés locaux. Certains ...

  3. Synthesis, structure, and characterization of two new bismuth(III) selenite/tellurite nitrates: [(Bi3O2)(SeO3)2](NO3) and [Bi(TeO3)](NO3)

    Science.gov (United States)

    Meng, Chang-Yu; Wei, Ming-Fang; Geng, Lei; Hu, Pei-Qing; Yu, Meng-Xia; Cheng, Wen-Dan

    2016-07-01

    Two new bismuth(III) selenite/tellurite nitrates, [(Bi3O2)(SeO3)2](NO3) and [Bi(TeO3)](NO3), have been synthesized by conventional facile hydrothermal method at middle temperature 200 °C and characterized by single-crystal X-ray diffraction, powder diffraction, UV-vis-NIR optical absorption spectrum, infrared spectrum and thermal analylsis. Both [(Bi3O2)(SeO3)2](NO3) and [Bi(TeO3)](NO3) crystallize in the monoclinic centronsymmetric space group P21/c with a=9.9403(4) Å, b=9.6857(4) Å, c=10.6864(5) Å, β=93.1150(10)° for [(Bi3O2)(SeO3)2](NO3) and a=8.1489(3) Å, b=9.0663(4) Å, c=7.4729(3) Å, β=114.899(2)° for Bi(TeO3)(NO3), respectively. The two compounds, whose structures are composed of three different asymmetric building units, exhibit two different types of structures. The structure of [(Bi3O2)(SeO3)2](NO3) features a three-dimensional (3D) bismuth(III) selenite cationic tunnel structure [(Bi3O2)(SeO3)2] 3∞ with NO3- anion group filling in the 1D tunnel along b axis. The structure of [Bi(TeO3)](NO3) features 2D bismuth(III) tellurite [Bi(TeO3)2]2∞ layers separated by NO3- anion groups. The results of optical diffuse-reflectance spectrum measurements and electronic structure calculations based on density functional theory methods show that the two compounds are wide band-gap semiconductors.

  4. Étude de propriétés structurales et dynamiques par dynamique moléculaire ab initio : application aux verres et aux liquides vitreux

    Science.gov (United States)

    Pasquarellol, A.

    2003-09-01

    La dynamique moléculaire ab initio est une méthode de simulation dans laquelle l'évolution de la structure électronique est prise en compte explicitement. Après une brève description de la méthode, son application aux systèmes vitreux est illustrée à travers des études de SiO2 et de GeSe2. Dans le contexte des systèmes vitreux, les méthodes ab initio servent tout d'abord à la génération de modèles structuraux. Ensuite, ces méthodes peuvent être étendues à l'étude des propriétés vibrationnelles. Les méthodes ab initio constituent aujourd'hui un outil indispensable permettant l'analyse d'une variété de propriétés expérimentales dans le contexte d'un seul cadre théorique cohérent.

  5. Localized iron supply triggers lateral root elongation in Arabidopsis by altering the AUX1-mediated auxin distribution.

    Science.gov (United States)

    Giehl, Ricardo F H; Lima, Joni E; von Wirén, Nicolaus

    2012-01-01

    Root system architecture depends on nutrient availability, which shapes primary and lateral root development in a nutrient-specific manner. To better understand how nutrient signals are integrated into root developmental programs, we investigated the morphological response of Arabidopsis thaliana roots to iron (Fe). Relative to a homogeneous supply, localized Fe supply in horizontally separated agar plates doubled lateral root length without having a differential effect on lateral root number. In the Fe uptake-defective mutant iron-regulated transporter1 (irt1), lateral root development was severely repressed, but a requirement for IRT1 could be circumvented by Fe application to shoots, indicating that symplastic Fe triggered the local elongation of lateral roots. The Fe-stimulated emergence of lateral root primordia and root cell elongation depended on the rootward auxin stream and was accompanied by a higher activity of the auxin reporter DR5-β-glucuronidase in lateral root apices. A crucial role of the auxin transporter AUXIN RESISTANT1 (AUX1) in Fe-triggered lateral root elongation was indicated by Fe-responsive AUX1 promoter activities in lateral root apices and by the failure of the aux1-T mutant to elongate lateral roots into Fe-enriched agar patches. We conclude that a local symplastic Fe gradient in lateral roots upregulates AUX1 to accumulate auxin in lateral root apices as a prerequisite for lateral root elongation.

  6. Les stratégies d'adaptation aux cyclones dans la région d ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    appui au développement de la culture du poivre et de la vanille pourrait contribuer à réduire la vulnérabilité des producteurs de clou de girofle en les aidant à s'adapter aux changements climatiques et à l'intensité croissante ...

  7. A. Lacassagne : de l’archive mineure aux Archives d’anthropologie criminelle

    Directory of Open Access Journals (Sweden)

    Philippe Artières

    2005-01-01

    Full Text Available En 1921, le médecin Alexandre Lacassagne offre à la ville de Lyon ses archives et son importante bibliothèque. Depuis son installation au début des années 1880, Lacassagne qui y détient la chaire de médecine légale et de toxicologie, est devenu l’une des figures les plus célèbre de la ville. Il est intervenu à plusieurs reprises dans les affaires municipales et notamment en matière d’hygiène urbaine, il a surtout pris part comme expert aux grandes affaires criminelles ; il a ainsi fait de Lyo...

  8. Des furoncles résistants aux antibiotiques: penser à la myiase !!

    Science.gov (United States)

    Ajili, Faida; Abid, Rim; Bousseta, Najeh; Mrabet, Ali; Karoui, Ghazi; Louzir, Bassem; Battikh, Riadh; Othmani, Salah

    2013-01-01

    Les myiases sont des infections parasitaires par des larves de mouches. La localisation cutanée doit être évoquée de retour d'un pays tropical devant une évolution inhabituelle de lésions cutanées. Nous rapportons une observation d'un militaire tunisien, ayant séjourné en République Démocratique du Congo. Il était atteint de myiase cutanée simulatrice d'une furonculose résistante aux antibiotiques. L'intérêt de cette observation est de souligner l'importance d’évoquer la myiase dont le traitement est simple et rapide chez un patient de retour de zone d'endémie. PMID:24106569

  9. Dynamiques de résistance aux normes révolutionnaires à Cuba

    OpenAIRE

    Geoffray, Marie-Laure

    2013-01-01

    Les normes du régime révolutionnaire sont, à Cuba, inscrites dans l’espace. Elles fonctionnent comme des signes performatifs qui à la fois rappellent constamment la présence du pouvoir et catégorisent les individus selon leur conformité aux normes. Mais, depuis la crise économique des années 1990, des logiques centrifuges à l’œuvre au sein de la société cubaine viennent remettre en question la capacité du régime à générer une socialisation révolutionnaire homogène. On observe des dynamiques s...

  10. Report on nuclear safety and transparency 2011 - Fontenay-aux-Roses CEA centre

    International Nuclear Information System (INIS)

    2012-06-01

    After a brief presentation of the Fontenay-aux-Roses CEA centre, this report indicates the different safety measures in the different nuclear base installations (INB) of this site (measures related to different risks, to emergency situations, to inspections and audits). It describes measures related to radiation protection: organisation, dosimetry results. It presents the different significant events which occurred in 2011 and were declared to the ASN. It discusses the results of measurements of liquid, gaseous and chemical releases from the installations and their impact on the environment. It addresses the radioactive waste management (measures to limit their volume and to limit their impact on health and on the environment, notably on water and soils, type and quantities of wastes stored in INBs). It presents the different measures and actions related to information transparency

  11. Observation spatiale et SIG: des outils pour cartographier les zones sensibles aux mouvements de terrain

    Directory of Open Access Journals (Sweden)

    Jean-Yves SCANVIC

    1994-12-01

    Full Text Available Les niveaux de sensibilité des sols aux mouvements de terrain ont été cartographiés dans différents bassins de risques en Bolivie, en Colombie et à Taïwan, selon une méthodologie développée au BRGM et fondée en partie sur l’extraction visuelle et numérique d’informations contenues dans les données de télédétection spatiale stéréoscopiques et leur gestion-valorisation dans un SIG. Ces cartes font apparaître l’intérêt de l’imagerie Spot pour la gestion du risque naturel.

  12. Safety Training: Ergonomie - Sensibilisation aux gestes et postures de travail

    CERN Multimedia

    Laetitia Laddada

    2004-01-01

    Nous vous proposons un nouveau cours d'ergonomie (durée : 1 jour) Sensibilisation aux gestes et postures de travail. A l'issue de cette formation, vous serez capable d'adopter et d'appliquer les principes de base de sécurité physique et d'économie d'efforts dans les manipulations d'objets. Les cours sont pris en charge par la Commission de Sécurité. L'inscription EDH est obligatoire. Pour plus d'information, veuillez consulter les pages Formation & Développement (Groupe Sécurité). FORMATION EN SECURITE SAFETY TRAINING Laetitia Laddada 73811 - 79236 safety.training@cern.ch

  13. Marjane Satrapi’s Poulet aux Prunes: fetish, desire, and illusions

    Directory of Open Access Journals (Sweden)

    Stefania Rimini

    2013-07-01

    Full Text Available Il saggio si propone di individuare e descrivere le sfumature erotiche e sentimentali del film Poulet aux prunes di Marjane Satrapi, felice adattamento dell’omonima graphic novel. Il racconto procede per scarti, ellissi, anticipazioni e flasback, dando luogo a una narrazione labirintica dalla singolare trama arabescante. Le sottili dinamiche seduttive messe in campo dal complesso stile di regia di Satrapi-Paronnaud vengono analizzate alla luce delle categorie feticistiche individuate da Massimo Fusillo, che offrono interessanti modelli di interazione fra desiderio e creatività. L’esito di tale indagine consente di ampliare il dibattito relativo al rapporto di scambio e interferenza fra oggetti, pulsioni e sguardi nel cinema contemporaneo.

  14. Neutron moderation at very low temperatures (1691); Moderation des neutrons aux tres basses temperatures (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Lacaze, A. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1961-04-15

    Starting from Harwell experiment carried out inside a low-power reactor, we intended to maintain a liquid hydrogen cell in a channel of the EL3 reactor (at Saclay) whose thermal neutrons flux is 10{sup 14} neutrons/cm{sup 2}/s. We tried to work out a device giving off an important beam of cold neutrons and able to operate in a way as automatic as possible during many consecutive day without a stop. Several circuits have already been achieved at very low temperatures but they brought out volumes and fluxes much lower than those we used this time. The difficulties we have met in carrying out such a device arose on the one hand from the very high energy release to which any kind of experiment is inevitably submitted when placed near the core of the reactor, on the other, hand from the very little room which is available in experimental channels of reactors. In such condition, it is necessary to use a moderator as effective as possible. This study is divided into three parts ; in the first part, we try to determine: a) conditions in which moderation takes place, hence the volume of the cell; b) materials likely to be used at low temperature and in pile; c) cooling system; hence we had to study fluid flow conditions at very low temperatures in very long ducts. The second part is devoted to the description of the device. The third part ventilates the results we have obtained. (author) [French] Partant de l'experience de Harwell faite dans une pile de faible puissance, nous nous sommes propose de maintenir une cellule d'hydrogene liquide dans un canal de la pile EL3 de Saclay dont le flux de neutrons thermiques est de 10{sup 14} neutrons par seconde et par cm{sup 2}. Nous avons cherche a realiser une installation donnant un faisceau de neutrons froids important, et pouvant fonctionner d'une maniere aussi automatique que possible, pendant des periodes de plusieurs jours sans arret. Plusieurs circuits aux tres basses temperatures ont deja ete realises, mais

  15. Etude sur les tendons en materiaux composites et leur application aux ancrages postcontraints

    Science.gov (United States)

    Chennouf, Adil

    L'objectif general de la presente these est d'evaluer le comportement a l'arrachement et au fluage d'ancrages injectes constitues de tendons en materiaux composites afin d'etablir des recommandations plus appropriees et realistes pour le dimensionnement et la conception. Quatre types de tendons en materiaux composites, deux a base de fibres d'aramide et deux a base de fibres de carbone, ont ete utilises dans l'etude. Les travaux de recherche de cette these ont porte notamment sur: (I) Une caracterisation physique et mecanique des tendons en materiaux composites utilises dans l'etude. (II) Une etude en laboratoire sur les coulis de scellement. La premiere etape de cette etude a concerne le developpement d'un coulis de scellement performant adapte aux tendons en materiaux composites et a differentes situations d'injection. La seconde etape a traite des essais de caracterisations physique et mecanique du coulis de scellement developpe comparativement a trois coulis de scellement usuels d'un meme rapport E/L de 0,4. (III) Une etude sur des modeles reduits d'ancrages injectes. (IV) Une etude sur des modeles d'ancrages a grande echelle. La synthese de ces etudes a permis d'enoncer les principales conclusions suivantes: (1) Les valeurs moyennes des charges de rupture des tendons en materiaux composites ont ete de 1% a 29% superieures a celles specifiees par les manufacturiers. (2) L'etude sur les coulis de scellement a permis le developpement de coulis de ciment repondant aux criteres fixes, soient une grande stabilite, une bonne fluidite, une legere expansion et de bonnes caracteristiques mecaniques. (3) Les tendons en materiaux composites ont montre des contraintes d'adherence maximum superieures a celles des tendons en acier. (4) Le type de fibre, la configuration et le fini de surface des tendons en materiaux composites gouvernent leur resistance a l'adherence. (5) L'introduction de sable et d'autres ajouts comme les fines de silice et la poudre d'aluminium au coulis

  16. Conséquences comportementales de la violence faite aux enfants

    Science.gov (United States)

    Al Odhayani, Abdulaziz; Watson, William J.; Watson, Lindsay

    2013-01-01

    Résumé Objectif Discuter des répercussions de la violence sur le développement comportemental durant l’enfance, mettre en évidence certains signes comportementaux susceptibles d’alerter les médecins à la présence d’une maltraitance continue d’un enfant et explorer le rôle précis du médecin de famille dans une telle situation clinique. Sources des données Une recension systématique a servi à examiner la recherche pertinente, les articles de révision clinique et les sites web des organismes de protection de la jeunesse. Message principal Le comportement d’un enfant est une manifestation extériorisée de sa stabilité et de sa sécurité intérieures. C’est une lentille au travers de laquelle le médecin de famille peut observer le développement de l’enfant pendant toute sa vie. Tous les genres de violence sont dommageables pour les enfants, qu’elle soit physique, affective ou psychologique, et peuvent causer des problèmes à long terme dans le développement du comportement et de la santé mentale. Les médecins de famille doivent connaître les indices de maltraitance et de négligence envers les enfants et être aux aguets de ces derniers afin d’entreprendre les interventions appropriées et améliorer les résultats pour ces enfants. Conclusion La violence faite aux enfants peut causer un développement psychologique désordonné et des problèmes de comportement. Les médecins de famille exercent un rôle important dans la reconnaissance des signes comportementaux laissant présager une maltraitance, ainsi que pour offrir de l’aide afin de protéger les enfants.

  17. Former aux TICE : entre compétences techniques et modèles pédagogiques

    OpenAIRE

    Jacques Béziat

    2012-01-01

    [Français] Cette contribution discute des enjeux et des limites d’une formation aux compétences techniques attendues des futurs enseignants d’école primaire. Une formation est certainement nécessaire pour espérer voir des pratiques pédagogiques avec les TICE se développer en classe. Mais ce n’est qu’un des leviers pour leur intégration dans les pratiques scolaires. Une formation aux TICE suppose que l’on mette l’accent sur l’analyse de pratiques. Plus que de former « simplement » à l’usage pé...

  18. Former aux TICE : entre compétences techniques et modèles pédagogiques

    Directory of Open Access Journals (Sweden)

    Jacques Béziat

    2012-01-01

    Full Text Available Cette contribution discute des enjeux et des limites d’une formation aux compétences techniques attendues des futurs enseignants d’école primaire. Une formation est certainement nécessaire pour espérer voir des pratiques pédagogiques avec les TICE se développer en classe. Mais ce n’est qu’un des leviers pour leur intégration dans les pratiques scolaires. Une formation aux TICE suppose que l’on mette l’accent sur l’analyse de pratiques. Plus que de former « simplement » à l’usage pédagogique d’outils numériques, il est indispensable de former à la complexité de leurs enjeux intellectuels et pratiques.

  19. Order of 30 March 1988 on licensing of gaseous radioactive effluent releases by the Fontenay-aux-Roses Nuclear Research Centre

    International Nuclear Information System (INIS)

    1988-01-01

    This Decree prescribes the documents and information the Fontenay-aux-Roses Nuclear Research Centre must provide to the Central Service for Protection against Ionizing Radiation (SCPRI) and lays down the permissible effluent release limits for the Centre [fr

  20. Recours aux TIC pour résoudre les problèmes d'eau en Ouganda ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les technologies de l'information et de la communication (TIC) peuvent grandement aider les collectivités à se préparer et à s'adapter aux effets des changements climatiques. Divers projets rendent compte de l'utilité de recourir à de nouvelles technologies (telles que le téléphone mobile) et à des technologies classiques ...

  1. Recours aux TIC pour résoudre les problèmes d'eau en Ouganda ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    15 janv. 2012 ... Les technologies de l'information et de la communication (TIC) peuvent grandement aider les collectivités à se préparer et à s'adapter aux effets des changements climatiques. Divers projets rendent compte de l'utilité de recourir à de nouvelles technologies (telles que le téléphone mobile) et à des ...

  2. Systèmes locaux d'alerte précoce et de réponse aux urgences ...

    African Journals Online (AJOL)

    SARAH

    30 janv. 2015 ... RÉSUMÉ. Objectif : L'étude vise à analyser le fonctionnement des observatoires de Suivi de la Vulnérabilité (OSV) et des. Structures Communautaires d'Alerte Précoce et des Réponses aux Urgences (SCAP-RU) au Niger. Méthodologie et résultats : l'étude a été conduite sur la base des enquêtes terrain ...

  3. Accroître la participation des femmes aux marchés du bétail | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    6 juin 2016 ... Lorsqu'elles gèrent leurs propres revenus, les femmes peuvent jouir d'un plus grand pouvoir de négociation, réduire la violence conjugale dont elles font l'objet et améliorer l'état nutritionnel de leurs enfants. Cela dit, il est difficile pour les femmes de participer aux marchés en raison de leur mobilité ...

  4. Facilitation de l'accès des personnes aux prises avec des difficultés ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Le nombre d'enfants aux prises avec des difficultés mentales est important et augmente à un rythme alarmant en Inde. On estime qu'environ 1 % des enfants sont atteints de troubles du spectre autistique, et que de 2 à 5 % des enfants souffrent d'un problème de traitement de l'information auditive. Ces enfants se heurtent à ...

  5. Vulnérabilité des systèmes d'approvisionnement en Eau Face aux ...

    African Journals Online (AJOL)

    C'est ainsi qu'il sera judicieux de renforcer la protection des dispositifs en place pour augmenter leur résilience aux inondations. A court terme, il est préconisé des technologies résilientes. A long terme, la solution durable serait d'intégrer une gestion adaptative de la ressource en eau au niveau des bassins versants pour ...

  6. Étude sur l'escalade de la violence faite aux femmes en Amérique ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    21 juin 2016 ... En Amérique centrale, on assiste à une escalade de la violence faite aux femmes et du nombre de meurtres de femmes (ou femicides). Or, il y a des lacunes sur le plan du signalement. Primo, malgré les efforts déployés par les organisations féministes, les groupes de défense des droits de la personne, les ...

  7. Accroître la participation des femmes aux marchés du bétail | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    6 juin 2016 ... Lorsqu'elles gèrent leurs propres revenus, les femmes peuvent jouir d'un plus grand pouvoir de négociation, réduire la violence conjugale dont elles font l'objet et améliorer l'état nutritionnel de leurs enfants. Cela dit, il est difficile pour les femmes de participer aux marchés en raison de leur mobilité ...

  8. GESTION BANCAIRE DU RISQUE DE NON-REMBOURSEMENT DES CREDITS AUX ENTREPRISES : UNE REVUE DE LA LITTERATURE

    OpenAIRE

    Véronique Rougès

    2003-01-01

    International audience; Les banquiers subissent un risque de nonremboursement des crédits aux entreprises. Ce risque peut être réduit lors des deux phases du crédit : lors de l'octroi, par une analyse du risque de défaillance et la rédaction de contrats incitatifs, et en cours de vie, par un suivi actif du crédit.

  9. Accès aux prix sur petit écran en vue de transformer les marchés ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    13 oct. 2010 ... Toute l'attention est portée à la vente; le prix a évidemment son importance, mais il est d'avis que l'information aux étapes précédant la vente importe elle ... In Sri Lanka, the government is aiming to double fish consumption per capita from 11 to 22 kg per year by the end of 2014 to boost dietary protein.

  10. Second meeting of the Atomic and Molecular Data Centre network. Fontenay aux Roses, 23-24 May 1980

    International Nuclear Information System (INIS)

    Katsonis, K.

    1980-11-01

    Summary report of the Second A+M Data Centre Network (DCN) meeting convened by the IAEA Nuclear Data Section at the CEA Laboratory at Fontenay-aux-Roses, France, 23-24 May 1980. The meeting was attended by 20 representatives from centres and groups from six Member States concerned with the coordinated international management of atomic and molecular data pertinent to controlled fusion research and technology

  11. Amélioration de la capacité d'adaptation sociale et écologique aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Amélioration de la capacité d'adaptation sociale et écologique aux changements climatiques dans le bassin versant du fleuve Orotoy, en Colombie. En Colombie, les inondations, les glissements de terrain et les sécheresses de plus en plus intenses se multiplient en raison des phénomènes météorologiques extrêmes.

  12. Amélioration de l'accès à la justice et aux services essentiels dans ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Amélioration de l'accès à la justice et aux services essentiels dans les établissements spontanés de Nairobi. Plus de la moitié des résidents de Nairobi, au Kenya, occupent des établissements spontanés, ou bidonvilles, dans des conditions difficiles. Leurs logements sont inadéquats et ils ont un accès insuffisant à l'eau ...

  13. Comment utiliser les TIC pour s'attaquer aux problèmes de santé ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    On appelle souvent cybersanté l'utilisation des technologies de l'information et de la communication (TIC) dans les systèmes de santé. ... à réfléchir aux tendances que l'on observe actuellement au chapitre de la cybersanté et du renforcement des systèmes de santé, et à trouver sa niche dans ce dynamique champ de ...

  14. Systèmes locaux d'alerte précoce et de réponse aux urgences ...

    African Journals Online (AJOL)

    Le Dispositif National de Prévention et de Gestion des Catastrophes et Crises Alimentaires (DNPGCCA) ne peut donc fonctionner en marge de cette initiative qui a gagné le mérite de faire avancer le système d'alerte précoce et de réponse aux urgences par une meilleure responsabilisation des communautés et des élus ...

  15. Etude de l'auto-adaptivité du filtre actif parallèle aux variations de la ...

    African Journals Online (AJOL)

    Pour assurer l'auto-additivité du filtre aux variations de la charge, deux schémas de régulation à base du régulateur P sont proposés, l'un pour la tension continue et ... To ensure filter auto-adaptivity, two control schemes based on P controller are proposed; one for dc voltage control and the second for the injected current ...

  16. Facteurs associes aux décès des nouveau-nés suspects d'infections ...

    African Journals Online (AJOL)

    Facteurs associes aux décès des nouveau-nés suspects d'infections bactériennes au Centre Hospitalier Universitaire Pédiatrique Charles de Gaulle de Ouagadougou, Burkina Faso. Solange Odile Yugbaré Ouédraogo, Désiré Méda, Lassina Dao, Fla Kouéta, Kam Ludovic, Ramata Ouédraogo Traoré, Diarra Yé ...

  17. Améliorer l'accès aux soins de santé en Afrique subsaharienne ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    7 juin 2016 ... Aux quatre coins de l'Afrique, les systèmes de santé sont minés par l'absence de ressources adéquates et le fardeau de plus en plus lourd des maladies. Pour lutter contre les maladies et améliorer le bien-être et la santé des populations, il faut s'assurer que les habitants peuvent accéder en temps ...

  18. Facilitation de l'accès des personnes aux prises avec des difficultés ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Cette subvention permettra à un petit groupe d'enfants de surmonter de sérieuses difficultés grâce à l'utilisation judicieuse des TIC et, dans la foulée, de valider une méthodologie peu coûteuse visant à faciliter l'apprentissage et la communication chez les enfants aux prises avec des difficultés mentales. La documentation ...

  19. Trousse de suivi et d'évaluation destinée aux initiatives d'adaptation ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    En Afrique, bon nombre de pays, de régions et d'organismes se dotent de programmes d'adaptation aux changements climatiques. Pour que ces programmes portent leurs fruits, ils devront régulièrement faire l'objet d'un suivi et d'une évaluation. Cette subvention servira à financer l'intégration d'un volet suivi et évaluation ...

  20. Application des innovations liées aux légumineuses pour la sécurité ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    L'Éthiopie présente l'un des taux de prévalence les plus élevés au monde quant à la malnutrition protéinocalorique et aux carences en micronutriments. Ce projet donnera lieu à l'application à grande échelle de nouveaux produits dérivés des légumineuses (les pois chiches et les haricots, par exemple) dans le sud de ...

  1. La politique européenne d’aide à la mise aux normes de qualité

    Directory of Open Access Journals (Sweden)

    Vialatte Philippe

    2001-05-01

    Full Text Available La Commission européenne peut aider les pays en développement à financer des programmes de mise aux normes de qualité pour contribuer à la lutte contre la pauvreté, améliorer les conditions de vie des populations locales et leur permettre de bénéficier encore plus largement des opportunités offertes par le marché européen.

  2. Phloem-specific expression of a melon Aux/IAA in tomato plants alters auxin sensitivity and plant development

    Directory of Open Access Journals (Sweden)

    Guy eGolan

    2013-08-01

    Full Text Available Phloem sap contains a large repertoire of macromolecules in addition to sugars, amino acids, growth substances and ions. The transcription profile of melon phloem sap contains over 1,000 mRNA molecules, most of them associated with signal transduction, transcriptional control, and stress and defense responses. Heterografting experiments have established the long-distance trafficking of numerous mRNA molecules. Interestingly, several trafficking transcripts are involved in the auxin response, including two molecules coding for auxin/indole acetic acid (Aux/IAA. To further explore the biological role of the melon Aux/IAA transcript CmF-308 in the vascular tissue, a cassette containing the coding sequence of this gene under a phloem-specific promoter was introduced into tomato plants. The number of lateral roots was significantly higher in transgenic plants expressing CmF-308 under the AtSUC2 promoter than in controls. A similar effect on root development was obtained after transient expression of CmF-308 in source leaves of N. benthamiana plants. An auxin-response assay showed that CmF-308-transgenic roots are more sensitive to auxin than control roots. In addition to the altered root development, phloem-specific expression of CmF-308 resulted in shorter plants, a higher number of lateral shoots and delayed flowering, a phenotype resembling reduced apical dominance. In contrast to the root response, cotyledons of the transgenic plants were less sensitive to auxin than control cotyledons. The reduced auxin sensitivity in the shoot tissue was confirmed by lower relative expression of several Aux/IAA genes in leaves and an increase in the relative expression of a cytokinin-response regulator, TRR8/9b. The accumulated data suggest that expression of Aux/IAA in the phloem modifies auxin sensitivity in a tissue-specific manner, thereby altering plant development.

  3. Droits des femmes et accès à l'eau et aux systèmes d ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    L'ONG Women in Cities International (WICI) tente de trouver des moyens de remédier à cette situation en Inde. Cette subvention lui permettra d'utiliser le ... Le CRDI aide l'Inde à s'adapter aux changements climatiques au moyen de données probantes, et en faisant preuve d'innovation. Le CRDI investit dans des solutions ...

  4. Les références aux documents en ligne dans les textes scientifiques

    Directory of Open Access Journals (Sweden)

    Marc Couture

    2010-01-01

    Full Text Available Avec le développement de la diffusion en ligne de documents scientifiques, la primauté reconnue traditionnellement à l’imprimé devient de moins en moins pertinente; les références à des ressources et documents en ligne forment ainsi une proportion significative des références dans certaines revues scientifiques, notamment celles qui, comme la RITPU, s’intéressent à l’information et à la communication. Dans cet article, on passe d’abord en revue les divers rôles des références répertoriés dans la littérature. On décrit ensuite les caractéristiques et les conditions permettant aux documents en ligne de jouer pleinement ces rôles. On montre enfin comment, dans l’adaptation française des normes de l’APA adoptée par la RITPU, certains choix touchant le format des notices des documents en ligne facilitent la tâche des évaluateurs et des lecteurs des articles. Par la même occasion, les auteurs y trouveront conseils et consignes visant à rendre plus pertinente et efficace cette dimension souvent négligée de la communication scientifique.

  5. La formation des enseignants aux TIC : allier pédagogie et innovation

    Directory of Open Access Journals (Sweden)

    Marcel Lebrun

    2004-01-01

    Full Text Available Relativement au champ des technologies éducatives, nous souhaitons étayer l’hypothèse suivante : si généralement on attribue le fait d’apprendre aux étudiants, il est aussi vrai que les enseignants apprennent, que les sociétés apprennent. La cohérence et la préoccupation de ces différents niveaux (étudiants, enseignants, institutions autour de la question de l’apprentissage peuvent, selon nous, être considérées comme un guide et comme un signe d’une éducation de qualité. Dans ce cas, les modèles généraux de l’apprentissage et du développement de dispositifs pédagogiques peuvent être interrogés afin d’élaborer de nouveaux usages et de nouvelles méthodes d’enseignement et de formation des enseignants, pour promouvoir l’innovation technologique dans les institutions et pour en valider la qualité.

  6. Report on transparency and nuclear safety 2015 - Fontenay-aux-Roses CEA centre

    International Nuclear Information System (INIS)

    2016-06-01

    This document proposes, first, a presentation of the Fontenay-aux-Roses CEA centre, of its activities and installations. Then it gives a rather detailed overview of measures related to safety and to radiation protection within these activities and installations. Next, it reports significant events related to safety and to radiation protection which occurred in 2015 and which have been declared to the French nuclear safety authority (ASN). It discusses the results of release measurements (liquid and gaseous effluents, radiological assessment, and chemical assessment for various installations) and the control of the chemical and radiological impact of these gaseous and liquid effluents on the environment. Finally, it addresses the issue of radioactive wastes which are stored in the different nuclear base installations of the Centre. It indicates the different measures aimed at limiting the volume of these warehoused wastes and addresses their impact on health and environment. Nature and quantities of warehoused wastes are specified. Remarks and recommendations of the Health, Safety and Working Conditions Committee (CHSCT) are given

  7. Cours Sécurité : Sensibilisation aux gestes et postures de travail

    CERN Multimedia

    DGS Unit

    2010-01-01

    Prochaine session le 21 octobre 2010. 12 places disponibles. Ce cours concerne toutes les personnes appelées à réaliser des manutentions manuelles dans le cadre de leurs activités. Contenu du cours : Théorie - Présentation des objectifs du programme ; - L'accident du travail (définition, coûts) ; - Statistiques CNAM ; - Notion d'anatomie (mécanique humaine) ; - Les différentes pathologies (lumbago, sciatique, hernie discale) ; - Discussion sur les problèmes particuliers rencontrés dans la vie courante. Pratique - Les efforts mécaniques sur la colonne dus aux mauvaises postures ; - Les principes de base de l'utilisation de la mécanique humaine ; - Exercices pratiques d'application (sur objets divers standards) ; - Prises de vues au caméscope des positions de chacun. Pour vous inscrire : https://edh.cern.ch/Document/Personnel/TRN?new=YES&...

  8. Des femmes réclament un accès plus sûr à l'eau et aux installations ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    20 févr. 2013 ... Les femmes qui ont été déplacées des bidonvilles du centre-ville de New Delhi vers des zones isolées en périphérie de la capitale s'exposent quotidiennement à des affronts et à des dangers lorsqu'elles vont chercher de l'eau ou se rendent aux toilettes publiques. Grâce aux marches exploratoires, un ...

  9. Les Nigérianes améliorent leur sort grâce aux légumes indigènes ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    6 juin 2016 ... Le microdosage des engrais, une innovation qui profite aux femmes du Sahel. Grâce à l'application localisée de petites quantités d'engrais (ou microdosage), alliée à l'amélioration des trous d'ensemencement afin de recueill. Voir davantageLe microdosage des engrais, une innovation qui profite aux ...

  10. Shoot-supplied ammonium targets the root auxin influx carrier AUX1 and inhibits lateral root emergence in Arabidopsis

    KAUST Repository

    Li, Baohai

    2011-03-24

    Deposition of ammonium (NH4 +) from the atmosphere is a substantial environmental problem. While toxicity resulting from root exposure to NH4 + is well studied, little is known about how shoot-supplied ammonium (SSA) affects root growth. In this study, we show that SSA significantly affects lateral root (LR) development. We show that SSA inhibits lateral root primordium (LRP) emergence, but not LRP initiation, resulting in significantly impaired LR number. We show that the inhibition is independent of abscisic acid (ABA) signalling and sucrose uptake in shoots but relates to the auxin response in roots. Expression analyses of an auxin-responsive reporter, DR5:GUS, and direct assays of auxin transport demonstrated that SSA inhibits root acropetal (rootward) auxin transport while not affecting basipetal (shootward) transport or auxin sensitivity of root cells. Mutant analyses indicated that the auxin influx carrier AUX1, but not the auxin efflux carriers PIN-FORMED (PIN)1 or PIN2, is required for this inhibition of LRP emergence and the observed auxin response. We found that AUX1 expression was modulated by SSA in vascular tissues rather than LR cap cells in roots. Taken together, our results suggest that SSA inhibits LRP emergence in Arabidopsis by interfering with AUX1-dependent auxin transport from shoot to root. © 2011 Blackwell Publishing Ltd.

  11. Alkoxy-auxins are selective inhibitors of auxin transport mediated by PIN, ABCB, and AUX1 transporters.

    Science.gov (United States)

    Tsuda, Etsuko; Yang, Haibing; Nishimura, Takeshi; Uehara, Yukiko; Sakai, Tatsuya; Furutani, Masahiko; Koshiba, Tomokazu; Hirose, Masakazu; Nozaki, Hiroshi; Murphy, Angus S; Hayashi, Ken-ichiro

    2011-01-21

    Polar auxin movement is a primary regulator of programmed and plastic plant development. Auxin transport is highly regulated at the cellular level and is mediated by coordinated transport activity of plasma membrane-localized PIN, ABCB, and AUX1/LAX transporters. The activity of these transporters has been extensively analyzed using a combination of pharmacological inhibitors, synthetic auxins, and knock-out mutants in Arabidopsis. However, efforts to analyze auxin-dependent growth in other species that are less tractable to genetic manipulation require more selective inhibitors than are currently available. In this report, we characterize the inhibitory activity of 5-alkoxy derivatives of indole 3-acetic acid and 7-alkoxy derivatives of naphthalene 1-acetic acid, finding that the hexyloxy and benzyloxy derivatives act as potent inhibitors of auxin action in plants. These alkoxy-auxin analogs inhibit polar auxin transport and tropic responses associated with asymmetric auxin distribution in Arabidopsis and maize. The alkoxy-auxin analogs inhibit auxin transport mediated by AUX1, PIN, and ABCB proteins expressed in yeast. However, these analogs did not inhibit or activate SCF(TIR1) auxin signaling and had no effect on the subcellular trafficking of PIN proteins. Together these results indicate that alkoxy-auxins are inactive auxin analogs for auxin signaling, but are recognized by PIN, ABCB, and AUX1 auxin transport proteins. Alkoxy-auxins are powerful new tools for analyses of auxin-dependent development.

  12. Alkoxy-auxins Are Selective Inhibitors of Auxin Transport Mediated by PIN, ABCB, and AUX1 Transporters*

    Science.gov (United States)

    Tsuda, Etsuko; Yang, Haibing; Nishimura, Takeshi; Uehara, Yukiko; Sakai, Tatsuya; Furutani, Masahiko; Koshiba, Tomokazu; Hirose, Masakazu; Nozaki, Hiroshi; Murphy, Angus S.; Hayashi, Ken-ichiro

    2011-01-01

    Polar auxin movement is a primary regulator of programmed and plastic plant development. Auxin transport is highly regulated at the cellular level and is mediated by coordinated transport activity of plasma membrane-localized PIN, ABCB, and AUX1/LAX transporters. The activity of these transporters has been extensively analyzed using a combination of pharmacological inhibitors, synthetic auxins, and knock-out mutants in Arabidopsis. However, efforts to analyze auxin-dependent growth in other species that are less tractable to genetic manipulation require more selective inhibitors than are currently available. In this report, we characterize the inhibitory activity of 5-alkoxy derivatives of indole 3-acetic acid and 7-alkoxy derivatives of naphthalene 1-acetic acid, finding that the hexyloxy and benzyloxy derivatives act as potent inhibitors of auxin action in plants. These alkoxy-auxin analogs inhibit polar auxin transport and tropic responses associated with asymmetric auxin distribution in Arabidopsis and maize. The alkoxy-auxin analogs inhibit auxin transport mediated by AUX1, PIN, and ABCB proteins expressed in yeast. However, these analogs did not inhibit or activate SCFTIR1 auxin signaling and had no effect on the subcellular trafficking of PIN proteins. Together these results indicate that alkoxy-auxins are inactive auxin analogs for auxin signaling, but are recognized by PIN, ABCB, and AUX1 auxin transport proteins. Alkoxy-auxins are powerful new tools for analyses of auxin-dependent development. PMID:21084292

  13. Synthesis of bimetallic nanocompositions AuxPd1-x/γ-Al2O3 for catalytic CO oxidation

    Science.gov (United States)

    Zaytsev, S. Yu.; Plyusnin, P. E.; Slavinskaya, E. M.; Shubin, Yu. V.

    2017-11-01

    Colloidal suspensions of AuxPd1-x nanoalloys were prepared via hydrazine co-reduction of [AuCl4]- and [PdCl4]2- complex anions in aqueous solution. High molecular weight polymeric compounds polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), and cryptoionic surfactants (AF-6 and AF-12 neonols, Triton X-100) were used as surface capping agents. Nanoparticles prepared under different experimental conditions were immobilized on γ-Al2O3 supports. The removal of the capping agents from the surface of the active particles was achieved through calcination of samples in oxidative atmosphere (air, 500 °C). This pretreatment of the catalysts significantly enhances their performance. Powder XRD, TEM, and EDX were employed to characterize the structure, size, and composition of the AuxPd1-x/γ-Al2O3 catalysts. The immobilized particles consist of uniformly mixed alloys having multi-domain face-centered cubic structure with typical crystallite size of 3-6 nm. The activity of the prepared samples was examined with temperature-programmed CO oxidation reaction (TP-CO+O2). Triton X-100 surfactant is superior in a number of parameters. Among all AuxPd1-x/γ-Al2O3 catalysts tested, the one stabilized with Triton X-100 (0.4%Au-0.2%Pd@Triton X-100) was found to have the highest activity for conversion of CO into CO2.

  14. New quaternary alkali metal cadmium selenites, A2Cd(SeO3)2 (A = K, Rb, and Cs) and Li2Cd3(SeO3)4

    Science.gov (United States)

    Lü, Minfeng; Jo, Hongil; Oh, Seung-Jin; Ok, Kang Min

    2017-12-01

    A series of new alkali metal cadmium selenites, A2Cd(SeO3)2 (A = K, Rb, and Cs) and Li2Cd3(SeO3)4 have been synthesized in phase pure forms through hydrothermal and solid-state reactions. Structural analyses using single crystal X-ray diffraction indicate that while A2Cd(SeO3)2 and Li2Cd3(SeO3)4 reveal layered structures consisting of CdO6 and SeO3 polyhedra, their symmetry, bonding modes, and the orientation of lone pairs on Se4+ cations are different. A closer examination suggests that the observed structural variations found in the reported materials are attributed to the structure-directing effect of alkali metal cations with different sizes. Scanning electron microscopy/energy dispersive analysis by X-ray, thermogravimetric analysis, Infrared and UV-vis diffuse reflectance spectroscopy, transformation reactions under hydrothermal conditions, and local dipole moment calculations for the reported materials are also reported.

  15. Application du groupe de renormalisation aux conducteurs organiques quasi-unidimensionnels soumis a un champ magnetique

    Science.gov (United States)

    Hubert, Laurent

    Des conducteurs organiques fortement anisotropes presentent, sous l'effet d'un champ magnetique, une etonnante variete de proprietes physiques tel que: l'effet Shubnikov-de Haas, l'effet de Haas-van-Alphen, l'existence de cascades d'ondes de densite de spin apparentees a l'effet Hall quantique, reentrance vers la phase metallique pouvant provenir d'un 'breakdown' magnetique, et tout recemment la possibilite d'un confinement charge induit par le champ magnetique. A cela s'ajoute les nombreuses caracteristiques deja apparues en variant la pression hydrostatique ou la substitution chimique: separation spin-charge, localisation de la charge, transition spin-Peierls, antiferromagnetisme itinerant ou non, supraconductivite, et l'existence d'une frontiere commune entre les phases supraconductrice et antiferromagnetique. En vue de completer la description theorique du diagramme de phase generalise des conducteurs organiques, nous adaptons et elargissons la methode du groupe de renormalisation quantique (GRQ) au cas ou le champ magnetique est non nul. On sait deja que cette methode permet de resoudre le dilemme tout particulier des composes Q-1D, soit leur capacite de produire des transitions de phase malgre leur forte anisotropie et consequemment de leur faible dimensionalite. Cette methode est deja utilisee pour decrire le diagramme de phase temperature versus pression des sels de Bechgaard, de leurs analogues souffres et mixtes. Le GRQ permet aussi de comprendre comment des systemes anisotropes comme les conducteurs organiques peuvent se comporter comme des liquides de Luttinger a haute temperature et comme des liquides de Fermi ou condenses a basse temperature. Nous montrons que l'introduction d'un champ magnetique dans un regime de saut coherent interchai ne a deux particules n'apporte que de simples corrections aux lois d'echelles dans le canal zero son, alors qu'il introduit un mecanisme de brisure de paire dans le canal Cooper. Dans le regime de saut coherent a une

  16. Du devenir de la notion de documentaire à l’ONF : des discours aux formes

    Directory of Open Access Journals (Sweden)

    Caroline Zéau

    2015-05-01

    Full Text Available Résumé La production documentaire fut toujours l’armature du mandat de l’Office national du film du Canada. Pour garantir la légitimité du cinéma auprès des instances publiques, son fondateur John Grierson a pris appui sur l’assise conceptuelle de l’Idée documentaire, une conception programmatique du cinéma qui soumettait celui-ci à la cause publique. Plus que jamais aujourd’hui, l’héritage de John Grierson est invoqué pour caractériser les valeurs associées à la mission de l’ONF, comme en témoignent les documents de communication produits par l’organisme. Plusieurs questions se posent alors : pourquoi la résurgence du lexique griersonien est-elle jugée pertinente aujourd’hui ? Et quelles sont les équivalences présupposées par ce retour aux sources ? Dans cet article, l’auteure se propose d’étudier la place et les valeurs aujourd’hui accordées à la notion de documentaire et aux objets qu’elle recouvre au sein des discours et des formes produits par l’ONF dans le cadre de la mutation technologique qui redéfinit sa mission et ses priorités depuis 2008. Ainsi seront examinées les déclinaisons terminologiques qui s’y rapportent—sur le site ONF.ca et les plans stratégiques 2008-2013 et 2013-2018—parallèlement à l’étude des formes nouvelles de documentaires produites pour les canaux de diffusion numériques qui définissent le champ de l’art interactif. Abstract Documentary production has always been central to the mandate of the National Film Board of Canada (NFB. To ensure the legitimacy of film among public authorities, its founder John Grierson built on the conceptual foundation of the Documentary Idea, a programmatic concept of cinema that places the latter at the service of the public. Today more than ever, the legacy of John Grierson is understood to characterize the values associated with the mission of the NFB, as evidenced by the institution’s communication documents

  17. Exposition orale aux nanoparticules de dioxyde de titane (TiO2) : du franchissement de l’épithélium buccal et intestinal au devenir et aux effets dans l’organisme

    OpenAIRE

    Bettini, Sarah

    2014-01-01

    Face à l’utilisation exponentielle des nanomatériaux dans des produits de consommation courante, dont l’alimentation, les conséquences pour l’homme d’une exposition quotidienne aux faibles doses de nanoparticules posent des questions de santé publique. Parmi les différentes voies d’exposition, la voie orale reste la moins documentée, alors que des nanomatériaux sont couramment utilisés comme additifs alimentaires, ou incorporés `a des emballages au contact des aliments, de l’eau, pour b´en´ef...

  18. Syntheses and structural characterization of vanado-tellurites and vanadyl-selenites: SrVTeO_5(OH), Cd_2V_2Te_2O_1_1, Ca_3VSe_4O_1_3·H_2O and Ba_2VSe_3O_1_0

    International Nuclear Information System (INIS)

    Konatham, Satish; Vidyasagar, Kanamaluru

    2017-01-01

    Four new quaternary vanado-tellurites and vanadyl-selenites, namely, SrVTeO_5(OH)(1), Cd_2V_2Te_2O_1_1(2), Ca_3VSe_4O_1_3·H_2O(3) and Ba_2VSe_3O_1_0(4) have been synthesized and structurally characterized by single crystal X-ray diffraction. The oxidation state of vanadium is +5 in tellurites 1 and 2 and +4 in selenites 3 and 4. The structures of SrVTeO_5(OH)(1) and Cd_2V_2Te_2O_1_1(2) compounds consist of (VTeO_5(OH))"2"- and (V_2Te_2O_1_1)"4"-anionic chains respectively, which are built from tetrahedral VO_4 and disphenoidal TeO_4 moieties. Similarly the structures of Ca_3VSe_4O_1_3·H_2O(3) and Ba_2VSe_3O_1_0(4) respectively contain (VSe_2O_7)"2"- and (VSe_3O_1_0)"4"- anionic chains, which are made up of octahedral VO_6 and pyramidal SeO_3 units. Compounds 1 and 3 have been characterized by thermogravimetric and infrared spectroscopic methods. Compounds 1 and 2 are wide band gap semiconductors. - Graphical abstract: Ca_3VSe_4O_1_3·H_2O and Ba_2VSe_3O_1_0 compounds contain (VSe_2O_7)"2"- and (VSe_3O_1_0)"4"- chains. - Highlights: • Four new vanado-tellurites and vanadyl-selenites are synthesized. • Their structural features are different. • The vanado-tellurites are wide band gap semiconductors.

  19. Synthesis, second-harmonic generation (SHG), and photoluminescence (PL) properties of noncentrosymmetric bismuth selenite solid solutions, Bi2-xLnxSeO5 (Ln = La and Eu; x = 0-0.3)

    Science.gov (United States)

    Qi, Hai-Xin; Jo, Hongil; Oh, Seung-Jin; Ok, Kang Min

    2018-02-01

    A series of La3+ or Eu3+-doped noncentrosymmetric (NCS) bismuth selenite solid solutions, Bi2-xLnxSeO5 (x = 0.1, 0.2, and 0.3), have been successfully synthesized via standard solid-state reactions under vacuum with Bi2O3, La2O3 (or Eu2O3), and SeO2 as starting materials. Crystal structures and phase purities of the resultant materials were thoroughly characterized by powder X-ray diffraction using the Rietveld method. The results clearly show that the reported materials crystallize in the orthorhombic space group, Abm2 (No. 39), and exhibit pseudo-three-dimensional frameworks consisting of BiO3, BiO5, and SeO3 polyhedra that share edges and corners. Detailed diffraction studies indicate that the cell volume of Bi2-xLnxSeO5 decreases with an increasing amount of Ln3+ on the Bi3+ sites. However, no ordering between Ln3+ and Bi3+ was observed in the Bi2-xLnxSeO5 solid solutions. Powder second-harmonic generation (SHG) measurements, using 1064 nm radiation, reveal that SHG efficiencies of Bi2-xLnxSeO5 solid solutions continuously decrease as more Ln3+ cations are added to the sites of polarizable Bi3+ cations. Photoluminescence (PL) measurements on Bi2-xEuxSeO5 exhibit three specific emission peaks at 592, 613, and 702 nm (5D0 → 7F1, 2, 4) owing to the 4f-4f intrashell transitions of Eu3+ ions.

  20. Variable dimensionality and framework found in a series of quaternary zinc selenites, A2Zn3(SeO3)4·xH2O (A = Na, Rb, and Cs; 0≤x≤1) and Cs2Zn2(SeO3)3·2H2O

    International Nuclear Information System (INIS)

    Lü, Minfeng; Jo, Hongil; Oh, Seung-Jin; Ok, Kang Min

    2017-01-01

    Five new alkali metal zinc selenites, A 2 Zn 3 (SeO 3 ) 4 ·xH 2 O (A = Na, Rb, and Cs; 0≤x≤1) and Cs 2 Zn 2 (SeO 3 ) 3 ·2H 2 O have been synthesized by heating a mixture of ZnO, SeO 2 and A 2 CO 3 (A = Na, Rb, and Cs), and characterized by X-ray diffraction (XRD) and spectroscopic analyses techniques. All of the reported materials revealed a rich structural chemistry with different frameworks and connection modes of Zn 2+ . While Rb 2 Zn 3 (SeO 3 ) 4 and Cs 2 Zn 3 (SeO 3 ) 4 ·H 2 O revealed three-dimensional frameworks consisting of isolated ZnO 4 tetrahedra and SeO 3 polyhedra, Na 2 Zn 3 (SeO 3 ) 4 , Cs 2 Zn 3 (SeO 3 ) 4 , and Cs 2 Zn 2 (SeO 3 ) 3 ·2H 2 O contained two-dimensional [Zn 3 (SeO 3 ) 4 ] 2- layers. Specifically, whereas isolated ZnO 4 tetrahedra and SeO 3 polyhedra are arranged into two-dimensional [Zn 3 (SeO 3 ) 4 ] 2- layers in two cesium compounds, circular [Zn 3 O 10 ] 14- chains and SeO 3 linkers are formed in two-dimensional [Zn 3 (SeO 3 ) 4 ] 2- layers in Na 2 Zn 3 (SeO 3 ) 4 . Close structural examinations suggest that the size of alkali metal is significant in determining the framework geometry as well as connection modes of transition metal cations. - Graphical abstract: Variable dimensions and frameworks were found in a series of quaternary zinc selenites, A 2 Zn 3 (SeO 3 ) 4 (A = Na, Rb and Cs). - Highlights: • Five novel quaternary zinc selenites are synthesized. • All the selenites with different structures contain polarizable d 10 and lone pair cations. • The size of alkali metal cations is significant in determining the framework geometry.

  1. Etude de l'auto-adaptivité du filtre actif parallèle aux variations de la ...

    African Journals Online (AJOL)

    ﮫـﻋ ﺔﯾﺮﻈﻧ. -ﻚـﻋ. Résumé. Cet article s'intéresse à l'amélioration des performances du filtre actif parallèle pour s'adapter d'une manière automatique aux variations de la charge. Ce filtre est un onduleur de tension à MLI destiné à éliminer les harmoniques de courant générés par un pont redresseur triphasé non commandé ...

  2. Renforcement de la capacité à réagir aux incidents de sécurité ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Renforcement de la capacité à réagir aux incidents de sécurité informatique en Amérique latine et dans les Caraïbes ... à favoriser la mise en place d'un réseau d'équipes d'intervention en cas d'incident de sécurité informatique et à renforcer les capacités, en particulier dans les secteurs les moins développés de la région.

  3. Annual progress report of the Fontenay-aux-Roses Research Group. January 1 to December 31 1977

    International Nuclear Information System (INIS)

    1977 at Fontenay-aux-Roses was dominated by the assembly and starting up of TFR 600, whereas at Grenoble it coincided with a period of full scientific production on Petula and Wega. On TFR 600 a study was made on discharges in the absence of a conducting shell and on plasma purity. Tokamak physics covered the analysis of the mechanism of disruptions and the dynamics of impurities on TFR 400, and the neutral injection (circular periplasmatron). Simultaneously the heating experiments and the diagnostics for TFR 600 were actively prepared, as well as the Torre II project [fr

  4. Marketers as Innovators: how ethnic marketing revisits ethnicity Marketing ethnique et innovation aux États-Unis

    OpenAIRE

    Marie-Christine Pauwels

    2009-01-01

    L’innovation aux États-Unis est ici vue sous un angle social et culturel. Il ne s’agit plus d’étudier l’innovation technologique, mais l’innovation en matière de produit. L’article aborde la création de valeur à travers la variable ethnique dans le domaine de la vente, du marketing et de la publicité. Les nouvelles tendances en matière d’ethno-marketing sont analysées, en particulier la manière dont les professionnels utilisent la notion d’ethnicité pour vendre des produits de consommation co...

  5. Epidémiologie moléculaire du rotavirus du groupe A associé aux ...

    African Journals Online (AJOL)

    Le rotavirus est la première cause de gastroentérites grave chez les enfants de moins de 5 ans. La gravité et la mortalité de la maladie sont majorées dans les pays à revenus faibles d'Asie du sud et d'Afrique subsaharienne. Au Cameroun, la forte prévalence des rotaviroses, associées aux spécificités génotypiques locales ...

  6. Genome-wide analysis of Aux/IAA gene family in Solanaceae species using tomato as a model.

    Science.gov (United States)

    Wu, Jian; Peng, Zhen; Liu, Songyu; He, Yanjun; Cheng, Lin; Kong, Fuling; Wang, Jie; Lu, Gang

    2012-04-01

    Auxin plays key roles in a wide variety of plant activities, including embryo development, leaf formation, phototropism, fruit development and root initiation and development. Auxin/indoleacetic acid (Aux/IAA) genes, encoding short-lived nuclear proteins, are key regulators in the auxin transduction pathway. But how they work is still unknown. In order to conduct a systematic analysis of this gene family in Solanaceae species, a genome-wide search for the homologues of auxin response genes was carried out. Here, 26 and 27 non redundant AUX/IAAs were identified in tomato and potato, respectively. Using tomato as a model, a comprehensive overview of SlIAA gene family is presented, including the gene structures, phylogeny, chromosome locations, conserved motifs and cis-elements in promoter sequences. A phylogenetic tree generated from alignments of the predicted protein sequences of 31 OsIAAs, 29 AtIAAs, 31 ZmIAAs, and 26 SlIAAs revealed that these IAAs were clustered into three major groups and ten subgroups. Among them, seven subgroups were present in both monocot and dicot species, which indicated that the major functional diversification within the IAA family predated the monocot/dicot divergence. In contrast, group C and some other subgroups seemed to be species-specific. Quantitative real-time PCR (qRT-PCR) analysis showed that 19 of the 26 SlIAA genes could be detected in all tomato organs/tissues, however, seven of them were specifically expressed in some of tomato tissues. The transcript abundance of 17 SlIAA genes were increased within a few hours when the seedlings were treated with exogenous IAA. However, those of other six SlIAAs were decreased. The results of stress treatments showed that most SIIAA family genes responded to at least one of the three stress treatments, however, they exhibited diverse expression levels under different abiotic stress conditions in tomato seedlings. SlIAA20, SlIAA21 and SlIAA22 were not significantly influenced by stress

  7. Transmissions radio haut débit sur fibres optiques appliquées aux transports terrestres

    OpenAIRE

    LOUM, D

    2009-01-01

    De nos jours, les liaisons par fibres optiques monomodes ou multimodes équipent de plus en plus des bâtiments, des lieux et sites de transports publics (gares, aéroports, autoroutes, ports ou plateformes multimodales). Les développements et tests de transmission radio sur fibre utilisant divers standards radio ont été effectués pour des accès aux services. Les débits restent limités à ceux définis par les normes correspondantes et donc très faibles vis-à-vis des possibilités offertes par la f...

  8. Le recours aux archives judiciaires pour étudier les habitudes de sommeil

    Directory of Open Access Journals (Sweden)

    Guillaume Garnier

    2009-10-01

    Full Text Available Les archives judiciaires possèdent de nombreux attraits, et certains sont parfois insoupçonnés. Les faits relatés dans les actes d’accusation par exemple, mais aussi les déclarations de témoins recèlent de petits détails sur les habitudes de sommeil qui passent souvent inaperçus aux yeux des historiens. Dans un corpus très large (du XVIIIe au xixe siècle on peut ainsi tenter de comprendre les logiques de sommeil : heures de coucher et lever, durée du sommeil, l’apparente vulnérabilité du repos nocturne, les déviances nocturnes, le lieu de sommeil. Mais dans une vue plus globale, les archives aident aussi à déterminer les rythmes nocturnes et notamment la place qu’y tient le sommeil. Les contraintes sociales et politiques, la dureté du travail et de la vie, l’importance de la religion transparaissent aussi pour former une culture spécifique du sommeil préindustriel.Judiciary records have many appealing aspects, some of which one would not suspect. What is related in indictment documents for instance, as well as in evidence statements, contains small details about sleeping habits that often go unnoticed by historians. Out of a very large corpus (from the xviiith till the xixth century, one can try and work out the rationale behind sleep: at what time people go to sleep or wake up, for how long, how vulnerable night sleep seems to be, nocturnal deviances, or where people sleep. But to a larger extent, records also help to determine nocturnal rhythms and more specifically the place that sleep holds in them. Social and political constraints, harshness of working and living conditions, the importance of religion, all show through and convey a specific culture of pre-industrial sleep.

  9. Hydrothermal synthesis and structural analysis of new mixed oxyanion borates: Ba{sub 11}B{sub 26}O{sub 44}(PO{sub 4}){sub 2}(OH){sub 6}, Li{sub 9}BaB{sub 15}O{sub 27}(CO{sub 3}) and Ba{sub 3}Si{sub 2}B{sub 6}O{sub 16}

    Energy Technology Data Exchange (ETDEWEB)

    Heyward, Carla, E-mail: cheywar@clemson.edu; McMillen, Colin D., E-mail: cmcmill@clemson.edu; Kolis, Joseph, E-mail: kjoseph@clemson.edu

    2013-07-15

    Several new borate compounds, Ba{sub 11}B{sub 26}O{sub 44}(PO{sub 4}){sub 2}(OH){sub 6} (1), Li{sub 9}BaB{sub 15}O{sub 27}(CO{sub 3}) (2), and Ba{sub 3}Si{sub 2}B{sub 6}O{sub 16} (3) were synthesized containing other hetero-oxyanion building blocks in addition to the borate frameworks. They were all prepared under hydrothermal conditions and characterized by single crystal and powder X-ray diffraction, and IR spectroscopy. Crystal data: For 1; space group P2{sub 1}/c, a=6.8909 (14) Å, b=13.629 (3) Å, c=25.851 (5) Å, β=90.04 (3)°; For 2; space group P-31c, a=8.8599 (13) Å, c=15.148 (3) Å; For 3; space group P-1, a=5.0414 (10) Å, b=7.5602 (15) Å, c=8.5374 (17) Å, α=77.15 (3)°, β=77.84 (3)°, γ=87.41 (3)° for 3. Compounds 1 and 2 contain isolated oxyanions [PO{sub 4}]{sup 3−} and [CO{sub 3}]{sup 2−} respectively, sitting in channels created by the borate framework, while structure 3 has the [SiO{sub 4}]{sup 4−} groups directly bonded to the borate groups creating a B–O–Si framework. - Highlights: • Hydrothermal syntheses of three new mixed oxyanion borates are presented. • Ba{sub 11}B{sub 26}O{sub 44}(PO{sub 4}){sub 2}(OH){sub 6} contains isolated [PO{sub 4}]{sup 3−} in voids of the borate framework. • Li{sub 9}BaB{sub 15}O{sub 27}(CO{sub 3}) contains isolated [CO{sub 3}]{sup 2−} in channels created by the framework. • Ba{sub 3}Si{sub 2}B{sub 6}O{sub 16} has direct bonding of [SiO{sub 4}]{sup 4−} and borates creating a B–O–Si framework.

  10. Quelques exemples d'application aux composites stratitfiés de la théorie Bending-Gradient pour les plaques

    OpenAIRE

    Lebée , Arthur; Sab , Karam

    2011-01-01

    International audience; Ce travail présente l'application aux composites fibrés d'une nouvelle théorie de plaque. Ce modèle destiné aux plaques épaisses et anisotropes utilise les six inconnues statiques de la theorie de Kirchhoff-Love auxquelles sont ajoutées six nouvelles inconnues représentant le gradient dumoment de flexion. Nommé théorie Bending-Gradient, ce nouveaumodèle peut être considéré comme une extension aux plaques hétérogènes dans l'épaisseurs du modèle de Reissner-Mindlin ; ce ...

  11. L’éducation aux médias : contributions, pratiques et perspectives de recherche en sciences de la communication

    OpenAIRE

    Landry, Normand; Basque, Joëlle

    2015-01-01

    Cet article positionne l’éducation aux médias à la fois comme champ et comme objet d’étude privilégié de mise en application de perspectives critiques en communication et en éducation. À cet égard, il synthétise et problématise le champ théorique de l’éducation aux médias et en identifie les spécificités, les visées et les difficultés. De surcroît, il présente de manière critique le concept de « littératie médiatique », principale proposition théorique de l’éducation aux médias. Finalement, c...

  12. Barbara Laborde, De l’enseignement du cinéma à l’éducation aux médias

    OpenAIRE

    Mathy, Adrien

    2017-01-01

    L’éducation aux médias est-elle un effet de mode, ou un projet ambitieux, porteur de multiples promesses ? Qu’auraient à gagner l’enseignement du cinéma et l’éducation aux médias à être, sinon assimilés, du moins rapprochés ? Ces questionnements jalonnent l’ouvrage de Barbara Laborde, dont la contribution déconstruit patiemment les discours sur l’enseignement du cinéma et l’éducation aux médias. Dans ce travail d’envergure, Laborde développe un discours riche, ponctué d’exemples et d’encadrés...

  13. L'inégalité des territoires insulaires de la Caraïbe face aux menaces volcaniques

    Directory of Open Access Journals (Sweden)

    Thierry Lesales

    2008-02-01

    Full Text Available Les îles de la Caraïbe orientale sont particulièrement exposées aux éruptions volcaniques. L’ensemble des Petites Antilles comprend en effet une vingtaine de volcans actifs, aux styles éruptifs parmi les plus dangereux et destructeurs. La définition de facteurs de vulnérabilité autorise des comparaisons et un classement des îles en fonction de leur niveau d’exposition. Cette approche permet d’attirer l’attention sur la nécessité d’une gestion proactive des risques volcaniques en contexte insulaireThe Eastern Caribbean islands are particularly exposed to volcanic eruptions. The Lesser Antilles arc indeed includes a score of active volcanoes, whose eruptive styles are among the most dangerous and destructive. The definition of vulnerability factors leads to some comparisons and a classification of the islands according to their level of exposure. This approach draws the attention to the imperative need for a proactive management of the volcanic risks in this insular context.

  14. Accessibilité aux emplois en France : le rôle de la distance à la ville

    Directory of Open Access Journals (Sweden)

    Mohamed Hilal

    2004-12-01

    Full Text Available L'objet de cet article est de modéliser les niveaux d’accessibilité potentielle aux emplois des communes françaises selon le rôle de la distance à la ville. Pour ce faire, nous présentons, tout d’abord, un modèle d’accessibilité et la méthode mise en œuvre pour calculer de façon systématique, à partir des données du réseau routier, une matrice des plus courts chemins, mesurés en temps, entre les communes françaises. Ensuite, dans la deuxième partie, ces distances sont intégrées dans le modèle d’accessibilité retenu afin de mesurer la disponibilité potentielle aux emplois selon la distance au pôle urbain le plus proche et selon les principales catégories d’espace du zonage en aires urbaines et de son complément rural. Enfin, la mesure d’accessibilité potentielle est comparée à plusieurs mesures d’accessibilité empirique.

  15. Genome-wide survey of Aux/IAA gene family members in potato (Solanum tuberosum): Identification, expression analysis, and evaluation of their roles in tuber development

    International Nuclear Information System (INIS)

    Gao, Junpeng; Cao, Xiaoli; Shi, Shandang; Ma, Yuling; Wang, Kai; Liu, Shengjie; Chen, Dan; Chen, Qin; Ma, Haoli

    2016-01-01

    The Auxin/indole-3-acetic acid (Aux/IAA) genes encode short-lived nuclear proteins that are known to be involved in the primary cellular responses to auxin. To date, systematic analysis of the Aux/IAA genes in potato (Solanum tuberosum) has not been conducted. In this study, a total of 26 potato Aux/IAA genes were identified (designated from StIAA1 to StIAA26), and the distribution of four conserved domains shared by the StIAAs were analyzed based on multiple sequence alignment and a motif-based sequence analysis. A phylogenetic analysis of the Aux/IAA gene families of potato and Arabidopsis was also conducted. In order to assess the roles of StIAA genes in tuber development, the results of RNA-seq studies were reformatted to analyze the expression patterns of StIAA genes, and then verified by quantitative real-time PCR. A large number of StIAA genes (12 genes) were highly expressed in stolon organs and in during the tuber initiation and expansion developmental stages, and most of these genes were responsive to indoleacetic acid treatment. Our results suggested that StIAA genes were involved in the process of tuber development and provided insights into functional roles of potato Aux/IAA genes. - Highlights: • A systematic analysis of the potato AUX/IAA gene family were performed. • StIAA genes were related to auxin perception and signal transduction. • Candidate StIAA genes likely related to tuber initiation and expansion were screened.

  16. Genome-wide survey of Aux/IAA gene family members in potato (Solanum tuberosum): Identification, expression analysis, and evaluation of their roles in tuber development

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Junpeng [State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A& F University, Yangling, Shaanxi 712100 (China); Innovation Experimental College, Northwest A& F University, Yangling, Shaanxi 712100 (China); Cao, Xiaoli; Shi, Shandang [State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A& F University, Yangling, Shaanxi 712100 (China); Ma, Yuling [State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A& F University, Yangling, Shaanxi 712100 (China); Innovation Experimental College, Northwest A& F University, Yangling, Shaanxi 712100 (China); Wang, Kai; Liu, Shengjie [State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A& F University, Yangling, Shaanxi 712100 (China); Chen, Dan [School of Life Sciences and Technology, Xidian University, Xi' an, Shaanxi 710071 (China); Chen, Qin [State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A& F University, Yangling, Shaanxi 712100 (China); Ma, Haoli, E-mail: mahaoli@nwsuaf.edu.cn [State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A& F University, Yangling, Shaanxi 712100 (China)

    2016-03-04

    The Auxin/indole-3-acetic acid (Aux/IAA) genes encode short-lived nuclear proteins that are known to be involved in the primary cellular responses to auxin. To date, systematic analysis of the Aux/IAA genes in potato (Solanum tuberosum) has not been conducted. In this study, a total of 26 potato Aux/IAA genes were identified (designated from StIAA1 to StIAA26), and the distribution of four conserved domains shared by the StIAAs were analyzed based on multiple sequence alignment and a motif-based sequence analysis. A phylogenetic analysis of the Aux/IAA gene families of potato and Arabidopsis was also conducted. In order to assess the roles of StIAA genes in tuber development, the results of RNA-seq studies were reformatted to analyze the expression patterns of StIAA genes, and then verified by quantitative real-time PCR. A large number of StIAA genes (12 genes) were highly expressed in stolon organs and in during the tuber initiation and expansion developmental stages, and most of these genes were responsive to indoleacetic acid treatment. Our results suggested that StIAA genes were involved in the process of tuber development and provided insights into functional roles of potato Aux/IAA genes. - Highlights: • A systematic analysis of the potato AUX/IAA gene family were performed. • StIAA genes were related to auxin perception and signal transduction. • Candidate StIAA genes likely related to tuber initiation and expansion were screened.

  17. Cinetique de la nucleation binaire non-isotherme et de la condensation binaire aux conditions dynamiques

    Science.gov (United States)

    Djikaev, Yuri

    La présente thèse est consacrée à la théorie de la condensation binaire. Premièrement, nous considérons la thermodynamique de la nucléation binaire, en nous concentrant sur l'énergie libre de formation d'une goutte et la distribution d'équilibre des gouttes, qui est essentielle pour la vitesse théorique de nucléation et dont le choix n'est toutefois pas unique. Une nouvelle distribution d'équilibre est proposée. Deuxièmement, nous développons la théorie cinétique de la nucléation binaire non-isotherme. Cette théorie traite de l'influence des effets thermiques sur la condensation binaire qui sont causés par la chaleur de condensation. Les molécules du mélange de vapeurs absorbées par une goutte de solution binaire lui transmettent de la chaleur de condensation, tandis que les molécules émises par la goutte lui enlèvent une telle chaleur. La température moyenne de la goutte s'accroît au fur et à mesure qu'elle grandit. Cet échauffement des gouttes croissantes diminue la vitesse de nucléation et influence d'autres caractéristiques du processus. Dans le cas où les chaleurs de condensation sont très petites par rapport à la fluctuation efficace de l'énergie d'une goutte l'équation cinétique peut être réduite à celle de Fokker et Planck. L'analyse de l'équation cinétique permet de déterminer la hiérarchie des échelles de temps de la nucléation binaire non-isotherme. Cela rend possible de séparer et décrire analytiquement l'étape de relaxation thermique pendant laquelle la distribution des gouttes selon la température s'approche d'une gaussienne, alors que leur distribution selon les nombres de molécules ne change guère. Finalement, nous étudions la condensation binaire isotherme aux conditions dynamiques. Dans ce cas la formation et la croissance des gouttes se passent en même temps que la métastabilité du mélange de vapeurs croît graduellement, atteint son maximum et décroît. C'est ainsi que la condensation

  18. Syntheses and structural characterization of vanado-tellurites and vanadyl-selenites: SrVTeO5(OH), Cd2V2Te2O11, Ca3VSe4O13·H2O and Ba2VSe3O10

    Science.gov (United States)

    Konatham, Satish; Vidyasagar, Kanamaluru

    2017-05-01

    Four new quaternary vanado-tellurites and vanadyl-selenites, namely, SrVTeO5(OH)(1), Cd2V2Te2O11(2), Ca3VSe4O13·H2O(3) and Ba2VSe3O10(4) have been synthesized and structurally characterized by single crystal X-ray diffraction. The oxidation state of vanadium is +5 in tellurites 1 and 2 and +4 in selenites 3 and 4. The structures of SrVTeO5(OH)(1) and Cd2V2Te2O11(2) compounds consist of (VTeO5(OH))2- and (V2Te2O11)4-anionic chains respectively, which are built from tetrahedral VO4 and disphenoidal TeO4 moieties. Similarly the structures of Ca3VSe4O13·H2O(3) and Ba2VSe3O10(4) respectively contain (VSe2O7)2- and (VSe3O10)4- anionic chains, which are made up of octahedral VO6 and pyramidal SeO3 units. Compounds 1 and 3 have been characterized by thermogravimetric and infrared spectroscopic methods. Compounds 1 and 2 are wide band gap semiconductors.

  19. Variable dimensionality and new uranium oxide topologies in the alkaline-earth metal uranyl selenites AE[UO2)(SeO3)2] (AE=Ca, Ba) and Sr[UO2)(SeO3)2] · 2H2O

    International Nuclear Information System (INIS)

    Almond, Philip M.; Peper, Shane M.; Bakker, Eric; Albrecht-Schmitt, Thomas E.

    2002-01-01

    Three new alkaline-earth metal uranyl selenites, Ca[UO 2 )(SeO 3 ) 2 ] (1), Sr[UO 2 )(SeO 3 ) 2 ] · 2H 2 O (2), and Ba[UO 2 )(SeO 3 ) 2 ] (3), have been prepared from the reactions of CaCO 3 and Ca(OH) 2 , SrCl 2 and Sr(OH) 2 , or BaCl 2 and Ba(OH) 2 with UO 3 and SeO 2 under mild hydrothermal conditions. Single-crystal X-ray diffraction experiments reveal that the structures of 1-3 differ in both connectivity and dimensionality even though all contain the same fundamental building unit, namely [UO 2 (SeO 3 ) 4 ]. This polyhedron consists of a linear uranyl unit that is bound by one chelating and three bridging selenite anions creating a pentagonal bipyramidal environment around the U(VI) center. The crystal structure of 1 contains one-dimensional ribbons where the edges are terminated by monodentate selenite anions. The interior of the ribbons are constructed from edge-sharing pentagonal bipyramidal UO 7 units. The structure of 2 is also one-dimensional; however, here there are chains of edge-sharing pentagonal bipyramidal UO 7 dimers that are connected by bridging selenite anions. Ba[(UO 2 )(SeO 3 ) 2 ] (3) is two-dimensional, and the highly ruffled anionic sheets present in this structure are formed from both bridging and chelating/bridging selenite anions bound to uranyl moieties. The anionic substructures in 1-3 are separated by Ca 2+ , Sr 2+ , or Ba 2+ cations. Crystallographic data (193 K, MoKα, λ=0.71073): 1, triclinic, space group P1-bar, a=5.5502(6) A, b=6.6415(7) A, c=11.013(1) A, α=104.055(2) deg., β=93.342(2) deg., γ=110.589(2) deg. , Z=2, R(F)=4.56% for 100 parameters with 1530 reflections with I>2σ(I); 2, triclinic, space group P1-bar, a=7.0545(5) A, b=7.4656(5) A, c=10.0484(6) A, α=106.995(1) deg., β=108.028(1) deg., γ=98.875(1) deg., Z=2, R(F)= 2.43% for 128 parameters with 2187 reflections with I>2σ(I); 3, monoclinic, space group P2 1 /c, a=7.3067(6) A, b=8.1239(7) A, c=13.651(1) A, β=100.375(2) deg., Z=4, R(F)=4.31% for 105 parameters

  20. Sensibilité aux antibiotiques des souches destaphylococcus aureus communautaires dans la région de Nouakchott (Mauritanie)

    Science.gov (United States)

    Salem, Mohamed Lemine Ould; Ghaber, Sidi Mohamed; Baba, Sidi El Wafi Ould; Maouloud, Mohamed Mahmoud Ould

    2016-01-01

    Introduction Staphylocoque aureus reste un pathogène majeur de l'homme causant des infections très diverses, cutanées, urinaires, pulmonaires ainsi que des septicémies. L'objectif de ce travail est d'évaluer la sensibilité des souches communautaires de Staphylococcus aureus isolées dans différents produits pathologiques vis-à-vis des principaux antibiotiques utilisés, dans la région de Nouakchott (Mauritanie). Méthodes Il s'agit d'une étude rétrospective réalisée sur 281 souches de Staphylococus aureus isolées entre Janvier 2014 et Août 2015 au laboratoire du Centre Hospitalier National et aux deux laboratoires privés de la ville de Nouakchott, dans différents produits pathologiques des patients non hospitalisés. La sensibilité aux antibiotiques a été déterminée par la méthode de diffusion de disques en milieu gélosé de Mueller Hinton selon les recommandations du CA-SFM. Résultats Le taux de résistance à la pénicilline G était élevé (96 à 100%). Le taux de SARM communautaires se situe entre 25 et 26% dans les suppurations, de 34,3% dans les ECBU et de 28% dans les spermocultures. La résistance aux Macrolides-Lincosamyne-Streptogramines (MLS), donnant le phénotype MLSb inductible, était retrouvée dans 6% des souches urinaires et 27% des souches isolées à partir des suppurations. L'activité des aminosides est variable, l'amikacine était active sur toutes les souches. L'activité du cotrimoxazol est faible (77% de résistance) et aucune résistance à la vancomycine n'a été notée. Conclusion L'activité de la Pénicilline G sur les souches de Staphylococcus aureus isolées dans la région de Nouakchott est quasi nulle et le taux de SARM communautaire est important atteignant jusqu'à 34%. Ceci pourrait être expliqué par l'usage anarchique de ces molécules dans notre pays. PMID:28154631

  1. Protéger la biodiversité : Les lois nationales régissant l'accès aux ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les directeurs. Susan Perkoff Bass est directrice du Programme interaméricain à l'Environmental Law Institute de Washington, D.C., aux États-Unis. Manuel Ruiz Muller est chercheur principal du Programme sur la biodiversité de la Sociedad Peruana de Derecho Ambiental ( SPDA ) à Lima, au Pérou.

  2. Localized Iron Supply Triggers Lateral Root Elongation in Arabidopsis by Altering the AUX1-Mediated Auxin Distribution[C][W][OA

    Science.gov (United States)

    Giehl, Ricardo F.H.; Lima, Joni E.; von Wirén, Nicolaus

    2012-01-01

    Root system architecture depends on nutrient availability, which shapes primary and lateral root development in a nutrient-specific manner. To better understand how nutrient signals are integrated into root developmental programs, we investigated the morphological response of Arabidopsis thaliana roots to iron (Fe). Relative to a homogeneous supply, localized Fe supply in horizontally separated agar plates doubled lateral root length without having a differential effect on lateral root number. In the Fe uptake-defective mutant iron-regulated transporter1 (irt1), lateral root development was severely repressed, but a requirement for IRT1 could be circumvented by Fe application to shoots, indicating that symplastic Fe triggered the local elongation of lateral roots. The Fe-stimulated emergence of lateral root primordia and root cell elongation depended on the rootward auxin stream and was accompanied by a higher activity of the auxin reporter DR5-β-glucuronidase in lateral root apices. A crucial role of the auxin transporter AUXIN RESISTANT1 (AUX1) in Fe-triggered lateral root elongation was indicated by Fe-responsive AUX1 promoter activities in lateral root apices and by the failure of the aux1-T mutant to elongate lateral roots into Fe-enriched agar patches. We conclude that a local symplastic Fe gradient in lateral roots upregulates AUX1 to accumulate auxin in lateral root apices as a prerequisite for lateral root elongation. PMID:22234997

  3. Pollution durable des sols par la chlordécone aux Antilles : comment la gérer ?

    OpenAIRE

    Cabidoche, Yves-Marie; Lesueur-Jannoyer, Magali

    2011-01-01

    La chlordécone, insecticide organochloré de synthèse, était utilisée dans les bananeraies antillaises avant 1993. Pourtant, elle contamine encore les ressources en eau, certaines denrées, et des organismes aquatiques. Très tôt, la recherche agronomique s’est mobilisée pour répondre aux questions posées pour la gestion de cette crise : Où sont les sols pollués? Est-ce une pollution durable ? La molécule est peu mobile. Des cartes de risques, fondées sur leur occupation rétrospective en bananer...

  4. Marketers as Innovators: how ethnic marketing revisits ethnicity Marketing ethnique et innovation aux États-Unis

    Directory of Open Access Journals (Sweden)

    Marie-Christine Pauwels

    2009-10-01

    Full Text Available L’innovation aux États-Unis est ici vue sous un angle social et culturel. Il ne s’agit plus d’étudier l’innovation technologique, mais l’innovation en matière de produit. L’article aborde la création de valeur à travers la variable ethnique dans le domaine de la vente, du marketing et de la publicité. Les nouvelles tendances en matière d’ethno-marketing sont analysées, en particulier la manière dont les professionnels utilisent la notion d’ethnicité pour vendre des produits de consommation courante à un marché de consommateurs de plus en plus exigeants, soit en ayant recours à une segmentation de ces consommateurs en micro-marchés toujours plus étroits, soit en privilégiant un marketing multi- ou trans-culturel.

  5. L'imaginaire du complot : discours d'extrême droite en France et aux Etats-Unis

    OpenAIRE

    Jamin, Jérôme

    2009-01-01

    Le nationalisme, la xénophobie, le racisme et l’antisémitisme, l’opposition aux élites, la stigmatisation des étrangers, les discours anti-immigrés, mais aussi l’autoritarisme, l’idéologie ‘loi et ordre’ (Law and order), l’antiparlementarisme et l’anticommunisme, entre autres traits caractéristiques, représentent quelques-uns des qualificatifs les plus souvent cités dans la littérature consacrée au populisme et à l’extrême droite. En fonction des partis politiques concernés, des contextes ins...

  6. The Politics of Religion in the United States Manifestations politiques de la religion aux États-Unis

    Directory of Open Access Journals (Sweden)

    Josef Braml

    2011-04-01

    Full Text Available Aux États-Unis, les attitudes religieuses ont plus d’influence sur les choix politiques que dans n’importe quelle autre démocratie occidentale. L’engagement religieux/moral de la droite chrétienne polarise les États-Unis, ce qui a des conséquences sur le plan électoral mais aussi sur les choix politiques réels. L’importance de la droite chrétienne dans la coalition électorale du Parti républicain oblige celui-ci à mettre l’accent sur les questions liées à la sécurité nationale, en particulier la lutte anti-terroriste, afin de mieux souder une coalition électorale hétérogène.

  7. Diversification and expression of the PIN, AUX/LAX and ABCB families of putative auxin transporters in Populus

    Directory of Open Access Journals (Sweden)

    Nicola eCarraro

    2012-02-01

    Full Text Available Intercellular transport of the plant hormone auxin is mediated by three families of membrane-bound protein carriers, with the PIN and ABCB families coding primarily for efflux proteins and the AUX/LAX family coding for influx proteins. In the last decade our understanding of gene and protein function for these transporters in Arabidopsis has expanded rapidly but very little is known about their role in woody plant development. Here we present a comprehensive account of all three families in the model woody species Populus, including chromosome distribution, protein structure, quantitative gene expression, and evolutionary relationships. The PIN and AUX/LAX gene families in Populus comprise 16 and 8 members respectively, and show evidence for the retention of paralogs following a relatively recent whole genome duplication. There is also evidence for differential expression across tissues within many gene pairs. The ABCB family is previously undescribed in Populus and includes 20 members, showing a much deeper evolutionary history including both tandem and whole genome duplication as well as probable loss. A striking number of these transporters are expressed in developing Populus stems and we suggest that evolutionary and structural relationships with known auxin transporters in Arabidopsis can point toward candidate genes for further study in Populus. This is especially important for the ABCBs, which is a large family and includes members in Arabidopsis that are able to transport other substrates in addition to auxin. Protein modeling, sequence alignment and expression data all point to ABCB1.1 as a likely auxin transport protein in Populus. Given that basipetal auxin flow through the cambial zone shapes the development of woody stems, it is important that we identify the full complement of proteins involved in this process. This work should lay the foundation for studies targeting specific proteins for functional characterization and in situ

  8. L’institutionnalisme de John Commons et les origines de l’État providence aux États-Unis

    Directory of Open Access Journals (Sweden)

    Isabel da Costa

    2010-12-01

    Full Text Available La politique officielle des États-Unis, soutenue par la pensée économique et juridique, était à l’origine le « laissez-faire » sur le marché et dans les relations de travail. Cet article analyse la construction d’un rôle légitime pour l’État dans la régulation sociale du marché du travail à travers l’ébauche de réglementations du travail et l’émergence de dispositifs de protection sociale aux États-Unis. Nous analyserons tout d’abord comment le mouvement progressiste a impulsé certaines réformes sociales établissant les prémisses d’une législation sociale ; nous nous attacherons ensuite à démontrer la contribution majeure de l’institutionnalisme de John Commons et de ses disciples de l’université du Wisconsin à la conception et au développement de l’État providence aux États-Unis.The official policy of the United States, backed by economic and legal thought, was originally “laissez-faire” on the market and in labor relations. This article analyzes the development of a legitimate role for the state in the social regulation of the labor market through the emergence of the early labor regulations and social protection schemes in the United States. We first analyze how the progressive movement brought about certain social reforms establishing the beginnings of social legislation; we will then focus on the major contribution of the institutionalism of John Commons and his followers from the University of Wisconsin to the design and the development of the welfare state in the United States.

  9. Genome-wide analysis and characterization of Aux/IAA family genes related to fruit ripening in papaya (Carica papaya L.).

    Science.gov (United States)

    Liu, Kaidong; Yuan, Changchun; Feng, Shaoxian; Zhong, Shuting; Li, Haili; Zhong, Jundi; Shen, Chenjia; Liu, Jinxiang

    2017-05-05

    Auxin/indole-3-acetic acid (Aux/IAA) family genes encode short-lived nuclear proteins that mediate the responses of auxin-related genes and are involved in several plant developmental and growth processes. However, how Aux/IAA genes function in the fruit development and ripening of papaya (Carica papaya L.) is largely unknown. In this study, a comprehensive identification and a distinctive expression analysis of 18 C. papaya Aux/IAA (CpIAA) genes were performed using newly updated papaya reference genome data. The Aux/IAA gene family in papaya is slightly smaller than that in Arabidopsis, but all of the phylogenetic subfamilies are represented. Most of the CpIAA genes are responsive to various phytohormones and expressed in a tissues-specific manner. To understand the putative biological functions of the CpIAA genes involved in fruit development and ripening, quantitative real-time PCR was used to test the expression profiling of CpIAA genes at different stages. Furthermore, an IAA treatment significantly delayed the ripening process in papaya fruit at the early stages. The expression changes of CpIAA genes in ACC and 1-MCP treatments suggested a crosstalk between auxin and ethylene during the fruit ripening process of papaya. Our study provided comprehensive information on the Aux/IAA family in papaya, including gene structures, phylogenetic relationships and expression profiles. The involvement of CpIAA gene expression changes in fruit development and ripening gives us an opportunity to understand the roles of auxin signaling in the maturation of papaya reproductive organs.

  10. Recours aux médicaments et aux consultations psychologiques chez les Canadiens atteints d'un trouble de l'humeur et/ou d'anxiété

    Directory of Open Access Journals (Sweden)

    Siobhan O'Donnell

    2017-01-01

    Full Text Available Introduction : L'étude décrit le recours aux médicaments sur ordonnance et aux consultations psychologiques au cours des 12 derniers mois chez les Canadiens adultes ayant déclaré avoir reçu un diagnostic de trouble de l'humeur et/ou d'anxiété, les caractéristiques sociodémographiques et cliniques associées à ce recours et les raisons invoquées pour ne pas y recourir. Méthodologie : L'Enquête sur les personnes ayant une maladie chronique au Canada - Composante sur les troubles de l'humeur et d'anxiété de 2014 a été utilisée. L'échantillon de l'étude (n = 2 916 a été divisé en quatre sous-groupes de traitement : (1 prend des médicaments seulement; (2 a reçu des consultations psychologiques seulement; (3 prend des médicaments et a reçu des consultations psychologiques; ou (4 n'a eu recours à aucun de ces deux traitements. Nous avons combiné les trois premiers sous-groupes et effectué des analyses descriptives et de régression logistique multivariée pour comparer ceux qui prenaient des médicaments et/ou avaient reçu des consultations psychologiques par rapport à ceux n'ayant pas eu recours à ces deux traitements. Nous avons pondéré toutes les estimations afin que les données soient représentatives de la population canadienne adulte vivant en logement privé dans l'une des 10 provinces et ayant déclaré avoir reçu un diagnostic de troubles de l'humeur et/ou d'anxiété. Résultats : La majorité (81,8 % des Canadiens adultes ayant déclaré avoir reçu un diagnostic de trouble de l'humeur et/ou d'anxiété ont indiqué prendre des médicaments et/ou avoir reçu des consultations psychologiques (47,6 % prenaient des médicaments seulement, 6,9 % avaient reçu des consultations psychologiques seulement et 27,3 % avaient eu recours aux deux modalités de traitement. Après ajustement des caractéristiques individuelles, le recours aux médicaments et/ou aux consultations psychologiques était significativement

  11. Short range order of selenite glasses

    Czech Academy of Sciences Publication Activity Database

    Neov, Dimitar; Gerasimova, I.; Yordanov, S.; Lakov, L.; Mikula, Pavol; Lukáš, Petr; Dimitriev, Y.

    1999-01-01

    Roč. 40, č. 2 (1999), s. 111-112 ISSN 0031-9090 R&D Projects: GA ČR GV202/97/K038; GA AV ČR KSK1048601 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.822, year: 1999

  12. Avaliação do efeito radioprotetor do selenito de sódio no processo de reparação tecidual em ratos Evaluation of the radioprotective effect of sodium selenite in the tissue repair process in rats

    Directory of Open Access Journals (Sweden)

    Fabrício M. Tuji

    2005-09-01

    Full Text Available OBJETIVO: Avaliar a ação radioprotetora do selenito de sódio no processo de reparação tecidual. MATERIAIS E MÉTODOS: Ratos Wistar foram submetidos a procedimento cirúrgico para a realização de ferida na região dorsal. Os animais foram divididos em quatro grupos experimentais: controle, selênio, irradiado e selênio-irradiado. Os grupos selênio e selênio-irradiado receberam 2,0 mg/kg de selenito de sódio, 48 horas após a cirurgia. Os grupos irradiado e selênio-irradiado foram submetidos à irradiação em dose única de 6 Gy, administrada somente nas bordas das feridas. Após 4, 7, 13 e 21 dias do procedimento cirúrgico, os animais foram sacrificados e avaliados por meio de análise morfológica, histoquímica e birrefringência do tecido. RESULTADOS: O aspecto estrutural e morfológico, assim como a qualidade do tecido e sua maturação através da quantidade e disposição dos feixes de fibras colágenas, juntamente com o seu grau de orientação macromolecular, permitiu observar a presença de intenso retardo provocado pela irradiação, bem como o efeito radioprotetor do selenito de sódio no processo de reparação. CONCLUSÃO: Dentro das condições experimentais utilizadas, o selenito de sódio apresentou-se como radioprotetor eficaz, visto que o processo de reparação no grupo selênio-irradiado comportou-se, histologicamente, semelhante ao grupo controle.OBJECTIVE: To evaluate the radioprotective effect of sodium selenite in the tissue repair process. MATERIALS AND METHODS: Male Wistar rats submitted to a surgical procedure to produce a wound in the dorsal region. These animals were then divided in four experimental groups: control, selenium, irradiated and selenium-irradiated. The selenium and selenium-irradiated groups received sodium selenite (2.0 mg/kg, 48 hours after surgery. The irradiated and selenium-irradiated groups received a single dose of 6 Gy, administered only in the borders of the wound. The animals were

  13. Synthesis and crystal structure of new uranyl selenite(IV)-selenate(VI) [C5H14N][(UO2)3(SeO4)4(HSeO3)(H2O)](H2SeO3)(HSeO4)

    International Nuclear Information System (INIS)

    Krivovichev, S.V.; Tananaev, I.G.; Myasoedov, B.F.; Kalenberg, V.

    2006-01-01

    Crystals of new uranyl selenite(IV)-selenate(VI) [C 5 H 14 N][(UO 2 ) 3 (SeO 4 ) 4 (HSeO 3 )(H 2 O)](H 2 SeO 3 )(HSeO 4 ) are obtained by the method of evaporation from aqueous solutions. Compound has triclinic lattice, space group P1-bar, a=11.7068(9), b=14.8165(12), c=16.9766(15), α=73.899(6), β=76.221(7), γ=89.361(6) Deg, V=2743.0(4) A 3 , Z=2. Laminated complexes (UO 2 ) 3 (SeO 4 ) 4 (HSeO 3 )(H 2 O)] 3- are the basis of the structure. [HSe(VI)O 4 ] - , [H 2 Se(IV)O 3 ] complexes and protonated methylbutylamine cations are disposed between layers [ru

  14. Du sport aux activités physiques de loisir : des formes culturelles et sociales bigarrées

    Directory of Open Access Journals (Sweden)

    Éric Dugas

    2007-07-01

    Full Text Available L'espace ludique des formes sociales des pratiques physiques accepte maintes variations. Du jeu informel et libre aux activités physiques institutionnelles (les sports, plusieurs catégories de situations motrices, distinctes des unes des autres, jalonnent l'espace des jeux sportifs. Après avoir défini et délimité, dans un premier temps, les contours et la richesse de l'univers des pratiques physiques ludiques, nous essayons, dans un second temps de mettre au jour le type de pratiques qui coïncident le mieux aux aspirations des pratiquants du xxie siècle. On s'aperçoit actuellement que malgré l'hégémonie du sport au sein de l'espace médiatique et économique, il se dessine néanmoins une tendance forte : la prédominance d’activités physiques ludiques de plus en plus autocontrôlées qui laissent l'initiative aux pratiquants et dans lesquelles les institutions sportives ne sont plus totalement ou pas du tout maître du jeu.From sport to leisure physical activities: mixed cultural and social formsThe game space of physical activities' social forms accepts many variations. From informal and free games to institutional physical activities (sports, several motor situation categories, distinct from each other, punctuate the space of physical games. After having specified and delimited the contours and richness of the world of playful physical activities, we will try to bring to light the kind of practices which coincide best with the 21st century's players or sports (women. Currently, we can see that in spite of sport's hegemony within the media and the economic spheres, a strong tendency is becoming apparent: the predominance of more and more self-controlled playful physical activities, which leave the initiative to players and in which governing bodies are not totally or not at all in command any more.Del deporte a las actividades de ocio: una mezcolanza en las formas culturales y socialesEl espacio lúdico de las formas sociales de

  15. Le rôle politique des revues conservatrices aux Etats-Unis depuis les années 1980

    Directory of Open Access Journals (Sweden)

    Marie-Cécile Naves

    2004-09-01

    Full Text Available L’article vise à étudier, à travers l’exemple de la théorie de la « Fin de l’Histoire » de Fukuyama, en quoi la revue américaine The National Interest est, à l’instar d’autres revues conservatrices, un instrument médiatique crucial pour la diffusion de certains idéaux du Parti Républicain aux Etats-Unis depuis le milieu des années 1980. Il s’agit par là même de réfléchir aux conditions de production et de diffusion de cette théorie, dans un contexte géopolitique et intellectuel exceptionnel, celui de la fin de la guerre froide. L’évolution des liens entre intellectuels et pouvoir politique américains, avec pour enjeu, depuis le début des années 1980, la politique étrangère, sont au cœur de cette réflexion.El artículo intenta estudiar a través del ejemplo de la teoría del « Fin de la Historia » de Fukuyama, hasta que punto la revista americana The National Interest es, a semejanza de otras revistas conservadoras, un instrumento crucial para la difusión de algunos ideales del partido republicano en los estados Unidos desde mediados de los años ochenta. Se trata de reflexionar sobre las condiciones de producción y de difusión de esta teoría, en un contexto geopolítico e intelectual excepcional, el del final de la guerra fría. El centro de esta reflexión es la evolución de las relaciones entre los intelectuales y el poder político americano, teniendo como telón de fondo, la política exterior.The article aims at studying, through the example of Fukuyama’s theory of the « End of History », how the American journal The National Interest, as other conservative journals, has, since the mid 1980s, been a crucial media instrument for the dissemination of some ideals of the Republican Party. We have thus to think about the conditions of production and dissemination of this theory in an exceptional geopolitical and intellectual context – the end of the cold war. The changing links between

  16. Desenvolvimento e aplicação de metodologia para auxílio da engenharia em automação residencial - MAER.

    OpenAIRE

    Robmilson Simões Gundim

    2007-01-01

    Este trabalho apresenta uma revisão bibliográfica sobre a teoria e a prática da Automação Residencial (AR) e também apresenta uma proposta de uma metodologia para auxílio da engenharia em AR intitulada MAEAR - Metodologia para Auxílio da Engenharia em Automação Residencial. Este trabalho apresenta também uma análise entre as principais teorias de controle desenvolvidas para a automação industrial, e a correlação das mesmas sobre sistemas de automação predial e residencial, assim como uma comp...

  17. Cinétique de photodéposition aux temps longs et réalisation de réseaux permanents modulables

    Science.gov (United States)

    Hugonnot, E.; Delville, J. P.

    2002-06-01

    La cinétique de photodéposition aux temps longs est étudiée expérimentalement dans une solution à base de chromate et théoriquement en utilisant un modèle thermodynamique de croissance de goutte. Un comportement universel de la croissance aux temps longs est alors trouvé. L'application de la photodéposition à la réalisation de réseaux holographiques est montrée et l'ajustement du modèle à partir de la figure de diffraction expérimentale permet de remonter à l'évolution temporelle de la morphologie induite par le champ laser.

  18. Modernité, corps et transformation de soi: Les salons de coiffure aux îles Tonga (Polynésie occidentale)

    NARCIS (Netherlands)

    Besnier, N.

    2013-01-01

    Aux îles Tonga, la fin des années 2000 fut marquée par une véritable explosion des salons de coiffure dans la petite capitale, Nuku’alofa. Ce phénomène reflète de nouvelles manières de concevoir le corps, par lesquelles les Tongiennes cherchent à se distancier de la vie traditionnelle sans néanmoins

  19. Étude de délimitation aux fins de l'Initiative régionale pour la lutte ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Étude de délimitation aux fins de l'Initiative régionale pour la lutte contre le tabac en Afrique. Financée par le CRDI et la Fondation Bill et Melinda Gates, l'initiative Analyses situationnelles de la lutte antitabac en Afrique (ASTA) a pour objectif de permettre de comprendre les facteurs déterminants du succès de la lutte ...

  20. Droit et accès des femmes à l'eau et aux systèmes d'assainissement ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2 mai 2012 ... Axe de rechercheLe projet vise à améliorer les services d'approvisionnement en eau et d'assainissement fournis aux femmes vivant dans les collectivités à faible revenu de New Delhi, de même qu'à favoriser de meilleurs rapports entre les habitants et les administrations locales.Le défi.

  1. ÉTUDE DE CAS – Côte d'Ivoire : De la forêt aux champs en Côte d ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    11 janv. 2011 ... Aujourd'hui, Buyo fait partie de la « nouvelle ceinture du café et du cacao » de la Côte d'Ivoire et est devenu un pôle d'attraction pour les immigrants. La plupart y viennent en quête de terres où s'adonner aux cultures marchandes. Certains trouvent du travail dans lesexploitations forestières ou dans les ...

  2. Aux origines de la masse particules élémentaires et symétries fondamentales

    CERN Document Server

    Iliopoulos, Jean

    2014-01-01

    Pourquoi les « particules élémentaires » qui forment toute la matière ont-elles une masse ? Étrange question qui semble être en contradiction avec toute notre intuition physique. Dans ce livre, nous montrons d'abord que la réponse à cette question est tout sauf évidente et ensuite que la clé peut se trouver dans la découverte récente d'une nouvelle particule à l'accélérateur géant LHC (Large Hadron Collider) situé au CERN, près de Genève. Nous proposons au lecteur une promenade guidée qui l'emmènera des confins de l'Univers pendant les premières fractions de seconde après le Big Bang, aux plus petits constituants de la matière tels que nous les apercevons dans nos laboratoires. Notre guide sera un principe profond de symétrie qui, de façon surprenante, semble déterminer la structure du monde.

  3. Flora Tristan: De la nécessité de faire bon accueil aux femmes étrangères

    Directory of Open Access Journals (Sweden)

    Martine Reid

    2014-10-01

    Full Text Available Dans son traité De la nécessité de faire bon accueil aux femmes étrangères (1835, Flora Tristan (1803-1844, l’écrivaine française qui adopte l’état psychologique d’une étrangère dans son propre pays, traite de la situation des femmes “étrangères” qui voyagent seules en France et/ou commencent une nouvelle vie dans le pays, en particulier à Paris. Politiquement engagée auprès des plus défavorisés à partir du socialisme, Tristan propose la création d’une association pour ces femmes. En assimilant les deux groupes d'"étrangères” (nationales et non nationales, car elle pense que le même type d’accueil doit être fourni à toutes, Tristan préconise l’aide à la voisine nécessiteuse, voisine qui est à la fois un sujet national ou un sujet en transit, une femme sans-papiers ou une réfugiée.

  4. De la théorie des opérateurs aux fondements de la mécanique quantique

    CERN Document Server

    Rinkel, Jean-Marc

    2016-01-01

    Ce livre est destiné aux étudiants en sciences, mathématiques ou physiques, au niveau master. La formalisation de l’infiniment petit de la mécanique quantique est un miracle d’abstraction, d’étonnement et d’émerveillement. Autant le développement de la physique classique (mécaniques newtonienne, lagrangienne, hamiltonienne et relativités) est lié à celui de la géométrie et du calcul tensoriel, autant l’émergence et le développement de la mécanique quantique sont liés à la théorie des espaces de Hilbert et à la théorie de la mesure. Dès lors qu’une observable (ce qui est accessible à une mesure expérimentale) est représentée par un opérateur sur un espace de Hilbert, les mathématiques se chargent de construire des mesures de probabilité sur le spectre de cet opérateur et ces mesures de probabilités deviennent une réalité physique dans les lois de transition de Born. Cet ouvrage décrit de façon précise le passage des mathématiques que l’on vient d’évoquer, �...

  5. Les ecarts de financement en matiere d'adaptation aux changements climatiques - avec la perspective des CPDN

    DEFF Research Database (Denmark)

    Olhoff, Anne; Bee, Skylar; Puig, Daniel

    En 2014, le Programme des Nations Unies pour l’Environnement (PNUE) a publié son premier rapport sur les écarts entre besoins et perspectives en matière d’adaptation (AGR 2014) (PNUE, 2014), lequel a permis de poser un cadre préliminaire pour évaluer ces écarts et d’établir une évaluation...... rapport sur les écarts financiers et les options permettant de les combler. Le rapport sera publié au printemps 2016. Cette mise à jour doit contribuer aux débats lors de la 21ème session de la Conférence des Parties (COP 21) à la Convention-Cadre des Nations Unies sur les Changements Climatiques (CCNUCC...... les besoins de financement présentes dans les composantes adaptation des Contributions Prévues Déterminées au niveau National (CPDN) (INDC) – soit les engagements post 2020 que les pays se proposent mettre en oeuvre dans le cadre d’un nouvel accord mondial sur les changements climatiques....

  6. Dépendance économique aux produits forestiers non ligneux : cas des ménages riverains des forêts de Boulon et de Koflandé, au Sud-Ouest du Burkina Faso

    DEFF Research Database (Denmark)

    Ouédraogo, M; Ouédraogo, D; Thiombiano, T

    2013-01-01

    taille du ménage, la superficie forestière et la densité de population du département qui affectent positivement la dépendance aux PFNL. Dans le cadre d’une politique de réduction de la pauvreté en milieu rural, il faut prendre des mesures qui favorisent l’accès durable des ménages les plus pauvres aux...

  7. Variable dimensionality and framework found in a series of quaternary zinc selenites, A{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}·xH{sub 2}O (A = Na, Rb, and Cs; 0≤x≤1) and Cs{sub 2}Zn{sub 2}(SeO{sub 3}){sub 3}·2H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Lü, Minfeng; Jo, Hongil; Oh, Seung-Jin; Ok, Kang Min, E-mail: kmok@cau.ac.kr

    2017-01-15

    Five new alkali metal zinc selenites, A{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}·xH{sub 2}O (A = Na, Rb, and Cs; 0≤x≤1) and Cs{sub 2}Zn{sub 2}(SeO{sub 3}){sub 3}·2H{sub 2}O have been synthesized by heating a mixture of ZnO, SeO{sub 2} and A{sub 2}CO{sub 3} (A = Na, Rb, and Cs), and characterized by X-ray diffraction (XRD) and spectroscopic analyses techniques. All of the reported materials revealed a rich structural chemistry with different frameworks and connection modes of Zn{sup 2+}. While Rb{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4} and Cs{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}·H{sub 2}O revealed three-dimensional frameworks consisting of isolated ZnO{sub 4} tetrahedra and SeO{sub 3} polyhedra, Na{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}, Cs{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}, and Cs{sub 2}Zn{sub 2}(SeO{sub 3}){sub 3}·2H{sub 2}O contained two-dimensional [Zn{sub 3}(SeO{sub 3}){sub 4}]{sup 2-} layers. Specifically, whereas isolated ZnO{sub 4} tetrahedra and SeO{sub 3} polyhedra are arranged into two-dimensional [Zn{sub 3}(SeO{sub 3}){sub 4}]{sup 2-} layers in two cesium compounds, circular [Zn{sub 3}O{sub 10}]{sup 14-} chains and SeO{sub 3} linkers are formed in two-dimensional [Zn{sub 3}(SeO{sub 3}){sub 4}]{sup 2-} layers in Na{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}. Close structural examinations suggest that the size of alkali metal is significant in determining the framework geometry as well as connection modes of transition metal cations. - Graphical abstract: Variable dimensions and frameworks were found in a series of quaternary zinc selenites, A{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4} (A = Na, Rb and Cs). - Highlights: • Five novel quaternary zinc selenites are synthesized. • All the selenites with different structures contain polarizable d{sup 10} and lone pair cations. • The size of alkali metal cations is significant in determining the framework geometry.

  8. Transport of radioselenium oxyanions by diffusion in unsaturated soils

    Energy Technology Data Exchange (ETDEWEB)

    Aldaba, David; Rigol, Anna; Vidal, Miquel [Barcelona Univ. (Spain). Dept. de Quimica Analitica; Garcia-Gutierrez, Miguel [CIEMAT, Dept. de Medioambiente, Madrid (Spain); Abrao, Taufik [State University of Londrina (UEL) (Brazil). Dept. of Electrical Engineering (DEEL)

    2015-07-01

    There is a lack of data on the diffusion of long-lived radionuclides in soils, especially of those originated from the leaching of radioactive waste in waste disposal facilities. Here, the simultaneous diffusion of two radioselenium species, which were postulated to be radioselenite and radioselenate, was examined for the first time in four soils at laboratory level by applying the planar-source method. The Gaussian-shaped experimental diffusion profile was deconvoluted into two Gaussian functions, and then the apparent diffusion coefficients (D{sub a}) were quantified for each species. Radioselenate D{sub a} values ranged from 1.4 x 10{sup -11} to 1.5 x 10{sup -10} m{sup 2}s{sup -1}, while those of radioselenite were two orders of magnitude lower (from 5.2 x 10{sup -13} to 2.7 x 10{sup -12} m{sup 2}s{sup -1}) for all samples and conditions tested. The radioselenite distribution coefficient values derived from D{sub a} correlated to soil properties, such as pH and Al/Fe mineral content, and thus were consistent with the factors controlling the sorption of selenium species in soils.

  9. Le projet Petits Films : du retour aux participants à la valorisation des données

    Directory of Open Access Journals (Sweden)

    Piccoli Vanessa

    2015-01-01

    Full Text Available En 2014, au sein du laboratoire ICAR (équipe InSitu / Cellule Corpus Complexe un projet appelé “Petits Films” a été conduit avec une double finalité : confectionner des petits films à partir de trois différents corpus et parallèlement mener une réflexion sur les modalités de réalisation, les finalités et les contraintes de ce type de réalisation. On considère que dans le domaine de l’analyse conversationnelle, dans lequel les chercheurs recourent de plus en plus à des corpus de données vidéo, la réalisation d’un petit film peut représenter non seulement un retour pour les participants, mais aussi un moyen de valorisation du corpus, d’un type d’approche en linguistique et plus largement de l’activité du laboratoire de recherche. Grâce à leur forme agréable et à leur courte durée, les petits films sont conçus pour la diffusion et la valorisation des méthodologies et des recherches, ils sont accessibles pour un large public, même de non-experts. Cependant, il est nécessaire de réfléchir aux questions juridiques et déontologiques que soulève cette opération.

  10. "If only you were a boy…": Friendship and sexual identity in Mireille Best's Hymne aux Murènes.

    Science.gov (United States)

    Schechner, Stephanie

    2018-01-02

    While much French fiction devoted to lesbians focuses on romantic relationships, Mireille Best's (1943-2005) first novel, Hymne aux Murènes (Hymn to the Moray Eels) (1986), depicts a wide variety of relationships between the lesbian protagonist, Mila, and the other young women staying in a sanatorium of sorts for the treatment of an unnamed illness. In this all-female environment, Best depicts relationships between Mila and Paule, a closeted lesbian employee of the sanatorium; between Mila and young women like Josette and Lilli, who are somewhat attracted to Mila but, for the most part, do not act on this attraction; and between very close heterosexual friends (Nicoli and Nicola). In so doing, Best expands the reader's notion of friendship between women and blurs the lines between lesbians and heterosexuals, guiding the reader toward a more complex understanding of female friendship in general and lesbian friendship in particular. Throughout the novel, several characters express frustration about Mila's gender identity by saying, "If only you were a boy…" While Mila remains romantically frustrated, she develops close friendships with several young women, and Best thus conveys optimism about lesbians' ability to form friendships during adolescence and early adulthood, a time of life when, according to her characters, the boundaries between heterosexuality and lesbianism seem less rigid than they might be later in life. In this essay, I focus primarily on Best's first novel, but I include brief reflections on an earlier short story that echoes the presentation of lesbians and friendship found in the novel.

  11. ETUDES ANALYTIQUES : Détection des OGM : du libre choix des consommateurs aux études de biovigilance

    Directory of Open Access Journals (Sweden)

    Bertheau Yves

    2000-07-01

    Full Text Available Les récentes affaires de semences conventionnelles de colza et de maïs contaminées par des traces d’OGM ont à nouveau, s’il en était besoin, rappelé à notre bon souvenir les besoins en méthodes de détection et d’identification des OGM fiables et sensibles. Les développements se poursuivent, certes bien plus lentement qu’initialement espéré du fait du nombre important de facteurs à maîtriser et du caractère relativement inédit de ce travail. Concernant des matrices alimentaires variées, cette détection se heurte au manque de recul dans plusieurs domaines tels que celui de l’extraction et la purification d’acides nucléiques en quantité et en qualité. Bien que développées pour satisfaire aux besoins réglementaires européens concernant l’alimentation humaine, ces méthodes devraient être aisément applicables dans d’autres domaines concernés par les OGM (étude des transferts de gènes par flux pollinique, éventuels transferts horizontaux, suivi des acides nucléiques lors de l’ingestion.... Au-delà des OGM, les méthodes mises en œuvre devraient présenter un intérêt dans d’autres domaines comme la microbiologie, l’épidémiologie ou l’authentification des composants biologiques d’un produit.

  12. Les stratégies des investisseurs : des bords de ville aux bords de mer

    Directory of Open Access Journals (Sweden)

    Sophie Cueille

    2004-03-01

    Full Text Available L’architecture de la villégiature a un prix. Construire des villes nouvelles, qu’elles soient balnéaires, thermales ou périurbaines, induit la mise en place de réseaux ferroviaires et viaires, d’édifices dévolus à la détente, les soins ou les jeux, d’hôtels et de maisons. Quels sont les investisseurs qui engagent d’importants financements en ces lieux ? Personnages de la vie politique, industrielle et bancaire, le plus souvent parisiens, tous se saisissent des besoins de la nouvelle société bourgeoise montante, consommatrice de loisirs dès le milieu du XIXe siècle. Si certains projets peuvent être initialement teintés d’une certaine forme de philanthropie, toutes les opérations deviennent très vite de véritables entreprises lucratives. Sociétés civiles en tous genres, concessions et affermages, les formules d’investissement s’adaptent au produit où souvent se mêlent intérêts publics et privés. La réussite de tels projets suscite également le financement de campagnes publicitaires importantes : journaux, affiches et guides sont publiés pour faire accourir la clientèle visée et ainsi rapporter aux investisseurs les profits escomptés.

  13. Smart Sensing of the Aux. Feed-water Pump Performance in NPP Severe Accidents Using Advanced GMDH Method

    Energy Technology Data Exchange (ETDEWEB)

    No, Young Gyu; Seong, Poong Hyun [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    In order to develop and verify the models, a number of data obtained by simulating station black out (SBO) scenario for the optimized power reactor 1000 (OPR1000) using MARS code were used. Most of monitoring systems for component have been suggested by using the directly measured data. However, it is very difficult to acquire data related to safety-critical component' status. Therefore, it is necessary to develop the new method that combines the data-based equipped with learning system and data miming technique. Many data-based modeling methods have been applied successfully to nuclear engineering area, such as signal validation, plant diagnostics and event identification. Also, the data miming is the process of analyzing data from different perspectives and summarizing it into useful information. In this study, the smart sensing technique was developed using advanced group method of data handing (GMDH) model. The original GMDH is an inductive self organizing algebraic model. The advanced GMDH model is equipped with a fuzzy concept. The proposed advanced GMDH model enhances the original GMDH model by reducing the effect of outliers and noise. The advanced GMDH uses different weightings according to their importance which is specified by the fuzzy membership grade. The developed model was verified using SBO accident simulation data for the OPR1000 nuclear power plant acquired with MARS code. Also, the advanced GMDH model was trained using the simulated development data and verified with simulated test data. The development and test data sets were independent. The simulation results show that the performance of the developed advanced GMDH model was very satisfactory, as shown in Table 1. Therefore, if the developed model can be optimized using diverse and specific data, it will be possible to predict the performance of Aux. feed water pump accurately.

  14. Cinética e equilíbrio de adsorção dos oxiânions Cr (VI, Mo (VI e Se (VI pelo sal de amônio quaternário de quitosana Kinetics and equilibrium of adsorption of oxyanions Cr (VI, Mo (VI and Se (VI by quaternary ammonium chitosan salt

    Directory of Open Access Journals (Sweden)

    Viviane A. Spinelli

    2005-07-01

    one gram of cross-linked quaternary chitosan salt adsorbed 68.3 mg of chromium, 63.4 mg of molybdenum and 90.0 mg of selenium. The adsorption process followed a pseudo second-order kinetic rate equation and the equilibrium regarding the three ions was reached after 200 minutes. The studies from X-ray dispersive energy showed that the main adsorption mechanism is ionic exchange among Cl- groups on the polymer surface by oxyanions from solution and the anionic exchanger showed the following selectivity order: Cr (VI > Mo (VI > Se (VI.

  15. Synthesis, structure, and characterization of two new bismuth(III) selenite/tellurite nitrates: [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and [Bi(TeO{sub 3})](NO{sub 3})

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Chang-Yu; Wei, Ming-Fang [Department of Chemistry and Materials, Yulin Normal University,Yulin, Guangxi 537000 (China); Geng, Lei, E-mail: lgeng.cn@gmail.com [Department of Materials Science and Engineering, Huaibei Normal University, Huaibei, Anhui 235000 (China); Hu, Pei-Qing; Yu, Meng-Xia [Department of Chemistry and Materials, Yulin Normal University,Yulin, Guangxi 537000 (China); Cheng, Wen-Dan [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

    2016-07-15

    Two new bismuth(III) selenite/tellurite nitrates, [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and [Bi(TeO{sub 3})](NO{sub 3}), have been synthesized by conventional facile hydrothermal method at middle temperature 200 °C and characterized by single-crystal X-ray diffraction, powder diffraction, UV–vis–NIR optical absorption spectrum, infrared spectrum and thermal analylsis. Both [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and [Bi(TeO3)](NO3) crystallize in the monoclinic centronsymmetric space group P2{sub 1}/c with a=9.9403(4) Å, b=9.6857(4) Å, c=10.6864(5) Å, β=93.1150(10)° for [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and a=8.1489(3) Å, b=9.0663(4) Å, c=7.4729(3) Å, β=114.899(2)° for Bi(TeO3)(NO3), respectively. The two compounds, whose structures are composed of three different asymmetric building units, exhibit two different types of structures. The structure of [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) features a three-dimensional (3D) bismuth(III) selenite cationic tunnel structure [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}] {sup 3}{sub ∞} with NO{sub 3}{sup −} anion group filling in the 1D tunnel along b axis. The structure of [Bi(TeO{sub 3})](NO{sub 3}) features 2D bismuth(III) tellurite [Bi(TeO{sub 3}){sub 2}]{sup 2}{sub ∞} layers separated by NO{sub 3}{sup −} anion groups. The results of optical diffuse-reflectance spectrum measurements and electronic structure calculations based on density functional theory methods show that the two compounds are wide band-gap semiconductors. - Graphical abstract: Two novel bismuth{sup III} selenite/tellurite nitrates [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) with 3D tunnel structure and [Bi(TeO{sub 3})](NO{sub 3}) with 2D layer structure have been firstly synthesized and characterized. Display Omitted - Highlights: • Two novel bismuth{sup III} nitrates [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and [Bi(TeO{sub 3})](NO{sub 3}) were firstly

  16. Assimilation ou fidélité aux valeurs du Vieux Monde ? La nouvelle et sa représentation de l’immigration juive aux Etats-Unis

    Directory of Open Access Journals (Sweden)

    Crystel Pinçonnat

    2001-06-01

    Full Text Available Quel modèle adopter : le respect de la tradition ou la voie de l’américanisation ? A partir de quelques nouvelles traduites du yiddish (New-Yorkaises de Lamed Shapiro, Le Fils qui venait d’Amérique d’Isaac Bashevis Singer et de l’américain (L’Oiseau-juif de Bernard Malamud, Eli le fanatique de Philip Roth et La Voix la plus forte de Grace Paley, cet article se propose d’étudier la représentation de la déchirure qui hante la communauté juive ashkénaze émigrée aux Etats-Unis : son tiraillement entre fidélité au passé et adhésion au présent.What model should be adopted: being respectful of tradition or becoming Americanized? A lot of Yiddish or American short stories raise the issue: New-York’s Women by Lamed Shapiro, The Son Who Came from America by Isaac Bashevis Singer,The Jewbird by Bernard Malamud Eli, The Fanatic by Philip Roth, and The Loudest Voice by Grace Paley. This article examines the representation these texts offer of the ongoing conflict within the Ashkenaze Jewish community, who came to the United States, torn between its past and its present, resistance and assimilation.¿Qué modelo adoptar : el respeto de la tradición o la vía de la americanización ? A partir de algunas novelas cortas traducidas del yiddish (New York’s Women de Lamed Shapiro, The Son Who Came from America de Isaac Bashevis Singer y del americano (The Jewbird de Bernard Malamud, Eli, The Fanatic de Philp Roth, y The Loudest Voice de Grace Paley, este artículo analiza la representación del dilema que desgarra a la comunidad judía asquenazie inmigrada a los Estados Unidos : la elección entre la fidelidad al pasado y la adhesión al presente.

  17. French regulations in the nuclear field and standards related to nuclear pressure equipment; Reglementation francaise dans le domaine nucleaire et normes relatives aux equipements sous pression nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Mourlon, S.; Limousin, S.; Van Hoecke, J.C. [Autorite de surete nucleaire 6, place du Colonel Bourgoin 75012 Paris (France)

    2007-07-01

    French regulations on nuclear pressure equipment have been updated with the December 12, 2005 Order related to Nuclear Pressure Equipment, so-called 'ESPN Order'. This Order is at the junction of regulations covering safety on the one hand and pressure equipment on the other hand. As regards manufacturing, the ESPN Order extends to nuclear pressure equipment the approach and essential requirements of the European Pressure Equipment Directive (PED - transposed in France by the December 13, 1999 Decree) while adding specific nuclear and radiation safety requirements. For in-service inspection, it sets additional provisions to those of the December 13, 1999 Decree so that the nuclear and radiation safety requirements applying in nuclear facilities are also taken into account for those equipment. The specific case of PWR main primary and secondary systems is covered by the November 10, 1999 Order. The ESPN Order leaves a major part to industrial codes and standards. Its publication makes it necessary to check that the codes used for nuclear pressure equipment comply with the new requirements and may induce modifications of the codes. Furthermore, as the market for operators of nuclear facilities and manufacturers of mechanical equipment is becoming global, these evolutions should be considered in a worldwide context. Last, the Nuclear Transparency and Security Act of June 13, 2006 - which created the Nuclear safety authority (ASN) with competence over nuclear and radiation safety, covering specifically nuclear pressure equipment - will induce further amendments of regulations. (authors) [French] La reglementation francaise en matiere d equipements sous pression nucleaires a ete refondee avec la parution de l arrete du 12 decembre 2005 relatif aux equipements sous pression nucleaires, dit 'arrete ESPN'. Ce texte se situe a l intersection des reglementations en matiere de surete, d une part, et d equipements sous pression, d autre part. En matiere de

  18. Renforcement des données probantes et des mesures relatives aux partenariats plurisectoriels en santé publique : un projet de recherche-action

    Directory of Open Access Journals (Sweden)

    C. D. Willis

    2016-01-01

    Full Text Available Introduction : L'initiative Partenariats plurisectoriels de l'Agence de la santé publique du Canada, gérée par le Centre de prévention et de contrôle des maladies chroniques (CPCMC, réunit différents partenaires en vue de concevoir, de mettre en œuvre et de faire progresser des approches novatrices visant à améliorer la santé de la population. Cet article décrit l'évolution et les premières priorités d'un projet de recherche-action (stratégie d'apprentissage et d'amélioration dont l'objectif est de faciliter l'amélioration continue de l'initiative de partenariat du CPCMC et de contribuer aux données probantes sur les partenariats plurisectoriels. Méthodologie : La stratégie d'apprentissage et d'amélioration du CPCMC pour les partenariats plurisectoriels repose sur les consultations avec le personnel et la haute direction du CPCMC et sur l'examen de cadres conceptuels liés aux partenariats plurisectoriels. Les consultations ont porté sur l'élaboration de l'initiative plurisectorielle, ses obstacles, ses facteurs de réussite et ses indicateurs d'efficacité. Nous avons fait une revue de littérature et consulté la littérature grise en appliquant une stratégie de recherche systématique puis nous avons résumé nos conclusions sous forme de comptes rendus. Résultats : Les consultations et l'examen de la littérature ont souligné l'importance de comprendre l'incidence des partenariats, d'élaborer une vision commune, de mettre en œuvre un système partagé de mesures et de créer des occasions d'échange de connaissances. C'est dans cette perspective que nous proposons une stratégie d'apprentissage et d'amélioration en six volets : 1 donner la priorité aux besoins en matière d'apprentissage, 2 relier les besoins aux données probantes, 3 utiliser des méthodes de collecte de données pertinentes, 4 analyser et synthétiser ces données, 5 fournir une rétroaction aux membres et aux équipes du CPCMC et 6 agir. Les

  19. Comprehensive genome-wide analysis of the Aux/IAA gene family in Eucalyptus: evidence for the role of EgrIAA4 in wood formation.

    Science.gov (United States)

    Yu, Hong; Soler, Marçal; San Clemente, Hélène; Mila, Isabelle; Paiva, Jorge A P; Myburg, Alexander A; Bouzayen, Mondher; Grima-Pettenati, Jacqueline; Cassan-Wang, Hua

    2015-04-01

    Auxin plays a pivotal role in various plant growth and development processes, including vascular differentiation. The modulation of auxin responsiveness through the auxin perception and signaling machinery is believed to be a major regulatory mechanism controlling cambium activity and wood formation. To gain more insights into the roles of key Aux/IAA gene regulators of the auxin response in these processes, we identified and characterized members of the Aux/IAA family in the genome of Eucalyptus grandis, a tree of worldwide economic importance. We found that the gene family in Eucalyptus is slightly smaller than that in Populus and Arabidopsis, but all phylogenetic groups are represented. High-throughput expression profiling of different organs and tissues highlighted several Aux/IAA genes expressed in vascular cambium and/or developing xylem, some showing differential expression in response to developmental (juvenile vs. mature) and/or to environmental (tension stress) cues. Based on the expression profiles, we selected a promising candidate gene, EgrIAA4, for functional characterization. We showed that EgrIAA4 protein is localized in the nucleus and functions as an auxin-responsive repressor. Overexpressing a stabilized version of EgrIAA4 in Arabidopsis dramatically impeded plant growth and fertility and induced auxin-insensitive phenotypes such as inhibition of primary root elongation, lateral root emergence and agravitropism. Interestingly, the lignified secondary walls of the interfascicular fibers appeared very late, whereas those of the xylary fibers were virtually undetectable, suggesting that EgrIAA4 may play crucial roles in fiber development and secondary cell wall deposition. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  20. Trigonometria como uma ferramenta no auxílio do cálculo de distâncias inacessíveis

    OpenAIRE

    Leite, Lélio Antônio de Oliveira

    2015-01-01

    Este trabalho tem como objetivo principal fornecer material de apoio para os professores e alunos de matemática dos Ensinos Fundamental e Médio e o foco são as aplicações da trigonometria. Iniciamos com algumas definições e resultados sobre esse tema e abordamos diversas situações problemas, visando exemplificar para o leitor a importância da trigonometria como uma ferramenta no auxílio do cálculo de distâncias inacessíveis. This work aims to provide background material for math teachers a...

  1. Le recours aux modeles dans l'enseignement de la biologie au secondaire : Conceptions d'enseignantes et d'enseignants et modes d'utilisation

    Science.gov (United States)

    Varlet, Madeleine

    Le recours aux modeles et a la modelisation est mentionne dans la documentation scientifique comme un moyen de favoriser la mise en oeuvre de pratiques d'enseignement-apprentissage constructivistes pour pallier les difficultes d'apprentissage en sciences. L'etude prealable du rapport des enseignantes et des enseignants aux modeles et a la modelisation est alors pertinente pour comprendre leurs pratiques d'enseignement et identifier des elements dont la prise en compte dans les formations initiale et disciplinaire peut contribuer au developpement d'un enseignement constructiviste des sciences. Plusieurs recherches ont porte sur ces conceptions sans faire de distinction selon les matieres enseignees, telles la physique, la chimie ou la biologie, alors que les modeles ne sont pas forcement utilises ou compris de la meme maniere dans ces differentes disciplines. Notre recherche s'est interessee aux conceptions d'enseignantes et d'enseignants de biologie au secondaire au sujet des modeles scientifiques, de quelques formes de representations de ces modeles ainsi que de leurs modes d'utilisation en classe. Les resultats, que nous avons obtenus au moyen d'une serie d'entrevues semi-dirigees, indiquent que globalement leurs conceptions au sujet des modeles sont compatibles avec celle scientifiquement admise, mais varient quant aux formes de representations des modeles. L'examen de ces conceptions temoigne d'une connaissance limitee des modeles et variable selon la matiere enseignee. Le niveau d'etudes, la formation prealable, l'experience en enseignement et un possible cloisonnement des matieres pourraient expliquer les differentes conceptions identifiees. En outre, des difficultes temporelles, conceptuelles et techniques peuvent freiner leurs tentatives de modelisation avec les eleves. Toutefois, nos resultats accreditent l'hypothese que les conceptions des enseignantes et des enseignants eux-memes au sujet des modeles, de leurs formes de representation et de leur approche

  2. L’INVESTISSEMENT EN BOURSE : LES NORMES DE LA FINANCE ISLAMIQUE APPLIQUEES AUX VALEURS DE LA PLACE BOURSIERE DE PARIS (CAC 40 et SBF 250)

    OpenAIRE

    EL KHAMLICHI, ABDELBARI

    2010-01-01

    En finance islamique, l’investissement en bourse est autorisé sous certaines conditions. Le choix des valeurs boursières dans lesquelles il serait possible d’investir conformément à la Charia se fait selon des critères financiers et extra financiers. Ainsi, il convient de s’intéresser aux secteurs d’activité de l’entreprise ainsi qu’à sa structure financière. Dans la pratique, il revient à un comité Charia, composé de jurisconsultes spécialistes de la loi islamique, de vérifier périodiquement...

  3. Un projet de développement forestier au Niger : problèmes d'adaptation des objectifs initiaux aux contraintes de réalisation

    OpenAIRE

    Clément, Jean

    1986-01-01

    Comme tous les pays du Sahel, le Niger est affronté à de graves problèmes de désertification et de déboisement dont les causes sont diverses : sécheresses successives,intensification du paturage provoquée par l'accroissement des troupeaux, consommation accrue de bois de feu... Sur la base d'une population totale de 6 OOO OOO habitants, la consommation de bois de feu peut être estimée à environ 4 OOO OOO m3 qu'il faut comparer aux 3 OOO OOO m3 d'accroissement en volume annuel des peuplements n...

  4. Resenha de: Applications de la photographie aérienne aux recherches des Sciences humaines dans le régions tropicales

    Directory of Open Access Journals (Sweden)

    Eurípedes Simões de Paula

    1965-03-01

    Full Text Available JHURAULT (J.. — Applications de la photographie aérienne aux recherches des Sciences humaines dans le régions tropicales. Coleção "Mémoires de photo-interprétation" dirigida por R. Chevalier. Publicação da "École Pratique des Hautes Études" (6e Section . Paris. S.E.V.P.E.N. 1964. 111 páginas de texto, 7 figuras e 19 pranchas fora do texto, 4 cartas coloridas, 8 fotos estereoscópicas.

  5. La participation des personnes utilisatrices aux exercices de planification et d'organisation des services de santé mentale au Québec

    Directory of Open Access Journals (Sweden)

    Michèle Clément

    2013-10-01

    Full Text Available Cet article documente la manière dont s'est renouvelé et s'est transformé au fil du temps le projet de faire participer les usagers aux exercices de planification et d'organisation des services de santé mentale au Québec (Canada. Pour ce faire, les auteurs reviennent sur l'ensemble des documents ministériels qui ont traité de cette question et dégage, pour les principaux moment-clés, les principales modalités de participation des usagers.

  6. Cartographie de la vulnérabilité globale d'une population citadine face aux risques naturels: le cas de Manizales

    Directory of Open Access Journals (Sweden)

    Anne-Catherine CHARDON

    1994-12-01

    Full Text Available Cette méthode cartographique sert à évaluer la vulnérabilité de la population d’une grande ville andine (Manizales, Colombie, exposée aux séismes et à de fréquents glissements de terrain. Sept facteurs naturels et huit facteurs socio-économiques, mesurés à l’échelle du quartier, sont intégrés, avec d’autre facteurs géographiques, dans une carte de vulnérabilité globale.

  7. De la production fruitière intégrée à la gestion écologique des vergers aux Antilles

    OpenAIRE

    Lavigne, Claire; Lesueur-Jannoyer, M.; de Lacroix, S.; Chauvet, G.; Lavigne, A.; Dufeal, D.

    2011-01-01

    La forte anthropisation aux Antilles françaises, la pression des monocultures de banane et de canne à sucre, et l'usage immodéré de pesticides, ont abouti à la pollution persistante d'une partie importante des sols de la SAU ainsi que des eaux de rivière et des nappes phréatiques. Si, dans les dix dernières années, la recherche de moyens de lutte biologique contre les insectes a été prioritaire, la lutte contre les adventices continue d'être un problème central pour les arboriculteurs qui ne ...

  8. Les Nigérianes améliorent leur sort grâce aux légumes indigènes

    International Development Research Centre (IDRC) Digital Library (Canada)

    à rester en santé. Malgré ce potentiel, la recherche n'a pas accordé la priorité aux espèces de légumes indigènes pour améliorer la sécurité alimentaire, la nutrition et les ... vue d'améliorer la sécurité alimentaire en milieu rural a porté sur la mise au .... germination, la lutte biologique contre les ravageurs et le tuteurage de ...

  9. L' éducation du patient aux Pays-Bas: une intégration importante dans la politique de santé.

    NARCIS (Netherlands)

    Bensing, J.M.; Visser, A.P.

    2000-01-01

    Aux Pays-Bas, l'éducation du patient s'est fortement développée au cours des trente dernières années tant à l'hôpital qu'en soins de santé primaires. Après des années 'pionière' au début des annéees 70, la pratique de l'éducation du patient a été introduite dans les standards de qualité et dans

  10. Pratiques documentaires aux Services industriels de Genève (SIG): vers une prise de conscience de la gestion documentaire de l'entreprise

    OpenAIRE

    Boussières, Eric; Chanoine, Elisabeth; Estermann-Wiskott, Yolande

    2012-01-01

    Certains collaborateurs des Services Industriels de Genève sont conscients qu’une gestion adaptée de la documentation constitue une valeur ajoutée pour l’entreprise. Pour cela, les SIG envisagent de créer une structure documentaire. Ce travail a pour objectifs de fournir aux SIG un état détaillé des collections existantes : monographies, périodiques, documentation technique, etc., des pratiques et des différents circuits documentaires présents dans l’entreprise. En plus, la présentation de de...

  11. Les centres de la petite enfance : soutien aux parents travailleurs ou lieu d’intervention auprès des familles ?

    OpenAIRE

    Deret, Anne

    2016-01-01

    La participation de l’État québécois aux services de garde, tant sur la plan du financement que de l’orientation éducative depuis les nouvelles dispositions de la politique familiale de 1997, est marquée par une orientation de plus en plus importante vers la prévention et l’intervention auprès des familles (particulièrement des familles dites à risque). Cet article rappelle comment cette orientation a pris place progressivement depuis les années 1970 dans les garderies du Québec et montre le ...

  12. Un territoire interface aux fonctionnements multiscalaires : l’espace transfrontalier franco-italo-monégasque

    Directory of Open Access Journals (Sweden)

    Fusco G.

    2012-10-01

    Full Text Available L’espace franco-italo-monégasque est un exemple d’interface caractérisé par des interactions transfrontalières à différentes échelles. Plus précisément, le micro-État monégasque constitue le pivot de cet espace interface, de part ses spécificités territoriales et fiscales, générant à la fois flux et régulations. Cette communication propose d’analyser les interfaces de différentes natures produites par cet espace transfrontalier particulier, à travers le prisme de l’espace-temps. Effectivement, toute interface verticale, caractérisée par des processus qui s’articulent à différents niveaux d’organisation, conduit à une prise en compte de multiples échelles et de leur jeu. Ici, les échelles analysées vont de l’espace transfrontalier de proximité (micro-échelle à l’espace transrégional transfrontalier (macro-échelle et sont définies à partir des flux qu’elles produisent selon de multiples « attracteurs ». Nous proposons d’envisager ces flux sous l’angle de l’espace-temps autour de Monaco, produit par les temps de déplacement routier, le réseau autoroutier étant la colonne vertébrale de ces interactions. L’objectif de cet article, proposant un exemple géographique du concept d’interface, est double. D’une part, il propose une approche d’analyse des interactions transfrontalières combinant deux corpus théoriques, celui des interfaces et celui de l’espace-temps. D’autre part, dans une optique plus opérationnelle de l’analyse des interfaces, il fournit un cas d’application qui renvoie aux défis de la représentation graphique de dynamiques complexes (représentation multiscalaire, schématisation des interactions, cartographie de processus spatio-temporels.

  13. Mosaïques de pierres dures : de la manufacture de Florence aux cours d’Europe

    Directory of Open Access Journals (Sweden)

    Annamaria Giusti

    2012-09-01

    Full Text Available Crée par Ferdinand Ier de Médicis en 1588, l���Opificio delle Pietre Dure a consacré son activité à la production de commessi et de mosaïques de pierres dures. Par leur fantaisie, leur perfection technique et la préciosité de leur matériau, ces œuvres sont particulièrement appréciées au-delà même des frontières du Grand-Duché de Toscane. En effet, les Médicis en ont fait cadeau aux souverains des autres cours d’Europe. Leur politique a provoqué une véritable émulation : Rodolphe II d’Augsbourg, enthousiasmé par les travaux qu’il commanda lui-même à Florence, décida le premier d’appeler des artisans florentins à Prague pour y créer une manufacture. Il est suivi par Louis XIV qui forme un atelier de pierres dures au sein des Gobelins, tandis qu’au xviiie siècle, Charles de Bourbon fonde deux manufactures sur le modèle de Florence, dans le royaume de Naples et en Espagne. Les mosaïques florentines continuent à jouir du prestige international sous le règne des Lorena (1737-1799. Pendant tout le xixe siècle, alors que Florence n’est plus le siège de la cour, l’Opificio compte parmi ses commanditaires Louis II de Bavière et le Tsar de Russie. Ces commandes sont les dernières d’une manufacture royale qui a duré pendant trois siècles. Désormais l’Opificio se consacre à la restauration des œuvres d’art.

  14. Des Connaissances Aux Politiques

    International Development Research Centre (IDRC) Digital Library (Canada)

    Dans beaucoup de pays en développement, la faible capacité du gouvernement est pratiquement la définition des problèmes de développement du pays. ...... Promouvoir l'échange des connaissances émanant des recherches ainsi que des outils et des résultats, et le dialogue entre les pays, institutions et donateurs.

  15. A Solid-State NMR Study of Selenium Substitution into Nanocrystalline Hydroxyapatite

    Science.gov (United States)

    Kolmas, Joanna; Kuras, Marzena; Oledzka, Ewa; Sobczak, Marcin

    2015-01-01

    The substitution of selenium oxyanions in the hydroxyapatite structure was examined using multinuclear solid-state resonance spectroscopy (ssNMR). The study was supported by powder X-ray diffractometry (PXRD) and wavelength dispersion X-ray fluorescence (WD-XRF). Samples of pure hydroxyapatite (HA300) and selenate (HA300-1.2SeO4) or selenite (HA300-1.2SeO3) substituted hydroxyapatites were synthesized using the standard wet method and heated at 300 °C to remove loosely bonded water. PXRD data showed that all samples are single-phase, nanocrystalline hydroxyapatite. The incorporation of selenite and selenate ions affected the lattice constants. In selenium-containing samples the concentration of Se was very similar and amounted to 9.55% and 9.64%, for HA300-1.2SeO4 and HA300-1.2SeO3, respectively. PXRD and ssNMR data showed that the selenite doping significantly decreases the crystallite size and crystallinity degree. 31P and 1H NMR experiments demonstrated the developed surface hydrated layer in all samples, especially in HA300-1.2SeO3. 1H NMR studies showed the dehydroxylation of HA during the selenium oxyanions substitution and the existence of hydrogen bonding in structural hydroxyl group channels. 1H→77Se cross polarization NMR experiments indicated that selenites and selenates are located in the crystal lattice and on the crystal surface. PMID:25997001

  16. Détermination de quelques paramètres hématologiques chez les agriculteurs exposés aux pesticides dans la région de Tlemcen

    OpenAIRE

    SAIDI, Fatima Zohra

    2015-01-01

    Résumé Les pesticides représentent une large gamme de produits utilisés de façon très variable. Les agriculteurs sont aujourd'hui le groupe le plus exposé aux risques de contact avec les pesticides. L'objectif de notre travail consiste à mettre en évidence les altérations hématologiques chez les hommes agriculteurs disposés aux pesticides comparés aux hommes témoins. Un prélèvement sanguin est réalisé afin de déterminer quelques paramètres hématologiques (FNS, numérations cellu...

  17. Largely enhanced photocatalytic activity of Au/XS2/Au (X = Re, Mo) antenna-reactor hybrids: charge and energy transfer.

    Science.gov (United States)

    Chen, Kai; Ding, Si-Jing; Luo, Zhi-Jun; Pan, Gui-Ming; Wang, Jia-Hong; Liu, Jia; Zhou, Li; Wang, Qu-Quan

    2018-02-22

    An antenna-reactor hybrid coupling plasmonic antenna with catalytic nanoparticles is a new strategy to optimize photocatalytic activity. Herein, we have rationally proposed a Au/XS 2 /Au (X = Re, Mo) antenna reactor, which has a large Au core as the antenna and small satellite Au nanoparticles as the reactor separated by an ultrathin two-dimensional transition-metal dichalcogenide XS 2 shell (∼2.6 nm). Due to efficient charge transfer across the XS 2 shell as well as energy transfer via coupling of the Au antenna and Au reactor, the photocatalytic activity has been largely enhanced: Au/ReS 2 /Au exhibits a 3.59-fold enhancement, whereas Au/MoS 2 /Au exhibits a 2.66-fold enhancement as compared to that of the sum of the three individual components. The different enhancement in the Au/ReS 2 /Au and Au/MoS 2 /Au antenna-reactor hybrid is related to the competition and cooperation of charge and energy transfer. These results indicate the great potential of the Au/XS 2 /Au antenna-reactor hybrid for the development of highly efficient plasmonic photocatalysts.

  18. Auxílio-reclusão: o instituto mal(maudito das políticas sociais com as políticas penais

    Directory of Open Access Journals (Sweden)

    Luiz Antônio Bogo Chies

    2015-12-01

    Full Text Available Resumo Tendo por eixo o instituto previdenciário auxílio-reclusão - pago aos dependentes do segurado de baixa renda preso - e a análise das representações sociais construídas a partir dessa prática, a pesquisa enfrenta uma dimensão da complexa interface entre a questão social e as políticas penais. A investigação utilizou como campo empírico o ambiente virtual, coletando dados através das mensagens postadas em blogs ou similares. Como referenciais teóricos privilegiou as perspectivas contemporâneas da sociologia do castigo e da economia política da punição, contemplando aspectos instrumentais e simbólicos das interseções em estudo. Seus resultados constatam a peculiar repulsa social no entorno do auxílio-reclusão, o que favorece apropriações no campo jurídico e político que, emolduradas por tecnicismos e populismos punitivos, ampliam a vulnerabilidade das conquistas sociais.

  19. Du karma aux planètes From the Karma to the Planets: Arakanese Healers and their Heterogeneous Practices

    Directory of Open Access Journals (Sweden)

    Céline Coderey

    2012-10-01

    Full Text Available En Arakan, les conceptions de la maladie et les pratiques thérapeutiques relevant du bouddhisme theravāda, de l’astrologie, du culte des esprits, de la médecine et de bien d’autres domaines forment un ensemble signifiant et hiérarchisé. Ensemble signifiant parce que malades et thérapeutes considèrent ces conceptions et pratiques comme indissociables les unes des autres et devant donc être combinées afin de mener à bien le processus de guérison. Ensemble hiérarchisé car, à l’intérieur de celui-ci, le bouddhisme occupe une place hégémonique au niveau des valeurs. Néanmoins, dans le domaine thérapeutique, son apport est limité. Ce n’est que combinées aux pratiques astrologiques, médicales, etc. que les pratiques bouddhiques peuvent contribuer à la prévention et au soin des maladies. L’attention est ici portée sur la manière dont laquelle cette totalité signifiante et hiérarchisée s’exprime dans les pratiques des thérapeutes. Sur la base d’une étude de cas, l’article montre que souvent les thérapeutes cumulent plusieurs formations et pratiques plus ou moins hétérogènes afin de pouvoir intervenir sur le plus grand nombre possible de facteurs de la maladie : déséquilibre des éléments corporels, mauvais karma, influences planétaires néfastes, agressions par des puissances maléfiques.In Arakan, sickness-related conceptions and therapeutic practices issuing from Theravada Buddhism, astrology, spirits cult and medicine form a meaningful and hierarchical whole. This whole is meaningful because patients and healers consider that it is the combination of various conceptions and various practices which makes sense and which guarantees the succes of the healing treatement. The whole is hierarchical because conceptions and practices are organised into a hierarchy where Buddhism occupies an hegemonic position. Nevertheless, in the healing field its contribution is limited. Only if combined with

  20. Uranium and selenium resistance in Cupriavidus metallidurans CH34

    International Nuclear Information System (INIS)

    Avoscan, L.; Untereiner, G.; Carriere, M.; Gouget, B.; Degrouard, J.

    2007-01-01

    Cupriavidus metallidurans CH34, a soil bacterium, is known to resist a variety of heavy metals and metalloids. Its capacity to resist, accumulate and transform selenium (Se as selenite or selenate) and uranium (U as uranyl-carbonate and uranyl-citrate) was investigated. C. metallidurans CH34 resists to high U concentrations (up to 10 mM) whatever its speciation. However, no major accumulation could be measured: U-carbonate and U-citrate are not bio-available for the bacteria. The anaerobic response of C. metallidurans CH34 to U will be looked for. C. metallidurans CH34 resists to high Se concentrations (up to 4 mM of selenite and 8 mM of selenate). Bacteria exposed to 2 mM of selenite accumulate 25 times more Se than when they are exposed to same concentration of selenate. Se resistance is characterized by the reduction of oxy-anions in the bacteria. Selenite is reduced to elemental Se by an intracellular process, but the metabolic fate of selenate is unknown. By combining three methods of speciation (X-ray absorption spectroscopy (XANES and EXAFS), HPLC-ICP-MS and SDS-PAGE coupled with particle induced X-ray emission (PIXE)), we both identified and specified the chemical intermediates formed by this bacterium upon exposure to these oxy-anions. Two mechanisms of reduction of Se oxides in C. metallidurans CH34 were highlighted. Assimilation transforms selenite and selenate into organic Se, identified as seleno-methionine and leads to its non-specific incorporation into bacterial proteins (presence of selenious proteins). Detoxication precipitates selenite in nano-particles of elemental Se. (authors)