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141 results on '"Manceau, Alain"'

1. Chemical Forms of Mercury in Pilot Whales Determined from Species-Averaged Mercury Isotope Signatures

Author

Manceau, Alain, Brossier, Romain, and Poulin, Brett A

Subjects
Digestive Diseases, mercury, demethylation, isotope fractionation, whale, inversion
Abstract

Marine mammals detoxify organic methylmercury (MeHg) as inorganic mercury selenide (HgSe), yet the nature of the reaction intermediate species and the tissue-specific redistribution of Hg species in the body are unknown. We report that the identity and proportion of the dominant Hg species in long-finned pilot whale (Globicephala melas) tissues can be obtained from the bulk variation of isotopic values of δ202Hg against the extent of demethylation (percentage of total Hg as MeHg, %MeHg) using an alternating regularized inversion method. Our analysis of isotope data from two previous studies supports that MeHg is demethylated as a tetraselenolate species (Hg(Sec)4), which further transforms into HgSe. Hg(Sec)4 occurs in the liver, kidneys, muscle, heart, and brain, whereas HgSe biomineralization occurs only in the liver and kidneys. This study provides a mathematical approach that facilitates probing the molecular-level chemistry of mercury in biological tissues using bulk isotopic data.

Published
2021

2. Isotope Fractionation from In Vivo Methylmercury Detoxification in Waterbirds

Author

Poulin, Brett A, Janssen, Sarah E, Rosera, Tylor J, Krabbenhoft, David P, Eagles-Smith, Collin A, Ackerman, Joshua T, Stewart, A Robin, Kim, Eunhee, Baumann, Zofia, Kim, Jeong-Hoon, and Manceau, Alain

Subjects
mercury, demethylation, isotopes, MDF, birds
Abstract

The robust application of stable mercury (Hg) isotopes for mercury source apportionment and risk assessment necessitates the understanding of mass-dependent fractionation (MDF) as a result of internal transformations within organisms. Here, we used high energy-resolution X-ray absorption near edge structure spectroscopy and isotope ratios of total mercury (δ202THg) and methylmercury (δ202MeHg) to elucidate the chemical speciation of Hg and the resultant MDF as a result of internal MeHg demethylation in waterbirds. In three waterbirds (Clark's grebe, Forster's tern, and south polar skua), between 17 and 86% of MeHg was demethylated to inorganic mercury (iHg) species primarily in the liver and kidneys as Hg-tetraselenolate [Hg(Sec)4] and minor Hg-dithiolate [Hg(SR)2] complexes. Tissular differences between δ202THg and δ202MeHg correlated linearly with %iHg [Hg(Sec)4 + Hg(SR)2] and were interpreted to reflect a kinetic isotope effect during in vivo MeHg demethylation. The product-reactant isotopic enrichment factor (ϵp/r) for the demethylation of MeHg → Hg(Sec)4 was -2.2 ± 0.1‰. δ202MeHg values were unvarying within each bird, regardless of Hg(Sec)4 abundance, indicating fast internal cycling or replenishment of MeHg relative to demethylation. Our findings document a universal selenium-dependent demethylation reaction in birds, provide new insights on the internal transformations and cycling of MeHg and Hg(Sec)4, and allow for mathematical correction of δ202THg values as a result of the MeHg → Hg(Sec)4 reaction.

Published
2021

3. TEXS: in-vacuum tender X-ray emission spectrometer with 11 Johansson crystal analyzers

Author

Rovezzi, Mauro, Harris, Alistair, Detlefs, Blanka, Bohdan, Timothy, Svyazhin, Artem, Santambrogio, Alessandro, Degler, David, Baran, Rafal, Reynier, Benjamin, Crespo, Pedro Noguera, Heyman, Catherine, Van Der Kleij, Hans-Peter, Van Vaerenbergh, Pierre, Marion, Philippe, Vitoux, Hugo, Lapras, Christophe, Verbeni, Roberto, Kocsis, Menhard Menyhert, Manceau, Alain, and Glatzel, Pieter

Subjects
Physics - Instrumentation and Detectors
Abstract

We describe the design and show first results of a large solid angle X-ray emission spectrometer that is optimized for energies between 1.5 keV and 5.5 keV. The spectrometer is based on an array of 11 cylindrically bent Johansson crystal analyzers arranged in a non-dispersive Rowland circle geometry. The smallest achievable energy bandwidth is smaller than the core hole lifetime broadening of the absorption edges in this energy range. Energy scanning is achieved using an innovative design, maintaining the Rowland circle conditions for all crystals with only four motor motions. The entire spectrometer is encased in a high-vacuum chamber that allocates a liquid helium cryostat and provides sufficient space for in situ cells and operando catalysis reactors., Comment: Manuscript (11 pages, 10 figures) plus supporting information (8 pages, 12 figures)

Published
2019
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4. High energy-resolution x-ray spectroscopy at ultra-high dilution with spherically bent crystal analyzers of 0.5 m radius

Author

Rovezzi, Mauro, Lapras, Christophe, Manceau, Alain, Glatzel, Pieter, and Verbeni, Roberto

Subjects
Physics - Instrumentation and Detectors
Abstract

We present the development, manufacturing and performance of spherically bent crystal analyzers (SBCAs) of 100 mm diameter and 0.5 m bending radius. The elastic strain in the crystal wafer is partially released by a "strip-bent" method where the crystal wafer is cut in strips prior to the bending and the anodic bonding process. Compared to standard 1 m SBCAs, a gain in intensity is obtained without loss of energy resolution. The gain ranges between 2.5 and 4.5, depending on the experimental conditions and the width of the emission line measured. This reduces the acquisition times required to perform high energy-resolution x-ray absorption and emission spectroscopy on ultra-dilute species, accessing concentrations of the element of interest down to, or below, the ppm (ng/mg) level., Comment: 9 pages, 8 figures

Published
2016
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6. DFT2FEFFIT: a density‐functional‐theory‐based structural toolkit to analyze EXAFS spectra.

Author

Manceau, Alain, Brossier, Romain, Mathon, Olivier, Lomachenko, Kirill A., Retegan, Marius, Glatzel, Pieter, and Steinmann, Stephan N.

Subjects
*RARE earth metals, *OPEN source software, *DENSITY functional theory, *FLUORAPATITE, *STRUCTURAL analysis (Engineering)
Abstract

This article presents a Python‐based program, DFT2FEFFIT, to regress theoretical extended X‐ray absorption fine structure (EXAFS) spectra calculated from density functional theory structure models against experimental EXAFS spectra. To showcase its application, Ce‐doped fluorapatite [Ca10(PO4)6F2] is revisited as a representative of a material difficult to analyze by conventional multi‐shell least‐squares fitting of EXAFS spectra. The software is open source and publicly available. [ABSTRACT FROM AUTHOR]

Published
2024
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15. Reply on 'Mercury Isotope Fractionation by Internal Demethylation and Biomineralization Reactions in Seabirds: Implications for Environmental Mercury Science': Principles and limitations of source tracing and process tracing with stable isotope signatures

Author

Manceau, Alain, Brossier, Romain, Janssen, Sarah, Poulin, Brett, Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), and Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA)

Subjects
[SDE]Environmental Sciences
Abstract

International audience; In Manceau et al. (2021), 1 we measured the mass-dependent fractionation (MDF) of mercury (Hg) stable isotopes, noted as δ 202 Hg, in 22 biological tissues from eight giant petrels (Macronectes spp.

Published
2022
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16. Fossil Bioapatites with Extremely High Concentrations of Rare Earth Elements and Yttrium from Deep-Sea Pelagic Sediments

Author

Manceau, Alain, Paul, Sophie A. L., Simionovici, Alexandre, Magnin, Valérie, Balvay, Mélanie, Findling, Nathaniel, Rovezzi, Mauro, Muller, Samuel, Garbe-Schönberg, Dieter, Koschinsky, Andrea, Manceau, Alain, Paul, Sophie A. L., Simionovici, Alexandre, Magnin, Valérie, Balvay, Mélanie, Findling, Nathaniel, Rovezzi, Mauro, Muller, Samuel, Garbe-Schönberg, Dieter, and Koschinsky, Andrea

Abstract

Detailed geochemical and mineralogical insights into some of the richest rare earth elements and yttrium (REY)-containing bioapatites from ocean-floor sediments have been provided by combining laser ablation inductively coupled plasma diffraction analysis, and Ce L3-edge high energy-resolution X-ray absorption near edge structure (HR-XANES) spectroscopy. Bioapatites at 1.94 and 4.70 m below the seafloor (mbsf) of the Clarion-Clipperton Zone (CCZ) of the Pacific Ocean have 26,600 (RSD = 15.7%, n = 20) and 30,300 (RSD = 14.6%, n = 10) mg/kg (mg/kg) total REY, respectively, and bioapatites at 2.28 and 6.95 mbsf of the Peru Basin have 15,500 (RSD = 15.6%, n = 20) and 15,700 (RSD = 17.8%, n = 29) mg/kg total REY, respectively. All bioapatite specimens have a variety of isomorphic substitutions in all atomic positions of the crystallographic structure. The average crystallochemical formula of bioapatites at 6.95 mbsf of the Peru Basin is [(PO4)2.71(SiO4)0.04(CO3,SO4)0.25][Ca4.57Na0.29Y0.04][F0.87Cl0.21]. All other substituents are below 0.04 atoms per formula unit. HR-XANES provides the first direct evidence for trivalent Ce in sediment apatites. The strong negative geochemical anomaly of Ce in fossil bioapatites is well explained by the occurrence of four valent Ce-MnO2 and CeO2 within the sediment and in seafloor ferromanganese nodules.

Published
2022
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21. Cellular remains in a ~3.42-billion-year-old subseafloor hydrothermal environment

Author

Cavalazzi, Barbara, primary, Lemelle, Laurence, additional, Simionovici, Alexandre, additional, Cady, Sherry L., additional, Russell, Michael J., additional, Bailo, Elena, additional, Canteri, Roberto, additional, Enrico, Emanuele, additional, Manceau, Alain, additional, Maris, Assimo, additional, Salomé, Murielle, additional, Thomassot, Emilie, additional, Bouden, Nordine, additional, Tucoulou, Rémi, additional, and Hofmann, Axel, additional

Published
2021
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22. TEXS: in-vacuum tender X-ray emission spectrometer with 11 Johansson crystal analyzers

Author

Rovezzi, Mauro, Harris, Alistair, Detlefs, Blanka, Bohdan, Timothy, Sviazhin, Artem, Santambrogio, Alessandro, Degler, David, Baran, Rafal, Reynier, Benjamin, Crespo, Pedro, Heyman, Catherine, Van Der Kleij, Hans-Peter, Van Vaerenbergh, Pierre, Marion, Philippe, Vitoux, Hugo, Lapras, Christophe, Verbeni, Roberto, Kocsis, Menhard, Manceau, Alain, Glatzel, Pieter, Svyazhin, Artem, Noguera Crespo, Pedro, Kocsis, Menhard Menyhert, Université Grenoble Alpes (UGA), French National Research Agency (ANR)ANR-10-EQPX-27-01, European Synchrotron Radiation Facility (ESRF), Institut des Sciences de la Terre (ISTerre), and Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Grenoble Alpes (UGA)-Université Gustave Eiffel-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])

Subjects
Cryostat, Nuclear and High Energy Physics, Materials science, Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, Bent molecular geometry, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, 7. Clean energy, law.invention, Crystal, Optics, law, 0103 physical sciences, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010306 general physics, Instrumentation, [PHYS]Physics [physics], Radiation, Spectrometer, business.industry, Liquid helium, Solid angle, X-ray, Beamlines, Instrumentation and Detectors (physics.ins-det), 021001 nanoscience & nanotechnology, 0210 nano-technology, business, Emission Spectrometer
Abstract

We describe the design and show first results of a large solid angle X-ray emission spectrometer that is optimized for energies between 1.5 keV and 5.5 keV. The spectrometer is based on an array of 11 cylindrically bent Johansson crystal analyzers arranged in a non-dispersive Rowland circle geometry. The smallest achievable energy bandwidth is smaller than the core hole lifetime broadening of the absorption edges in this energy range. Energy scanning is achieved using an innovative design, maintaining the Rowland circle conditions for all crystals with only four motor motions. The entire spectrometer is encased in a high-vacuum chamber that allocates a liquid helium cryostat and provides sufficient space for in situ cells and operando catalysis reactors., Manuscript (11 pages, 10 figures) plus supporting information (8 pages, 12 figures)

Published
2020
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23. Chemical Forms of Mercury in Blue Marlin Billfish: Implications for Human Exposure

Author

Manceau, Alain, Azemard, Sabine, Hédouin, Laetitia, Vassileva, Emilia, Lecchini, David, Fauvelot, Cecile, Swarzenski, Peter W, Glatzel, Pieter, Bustamante, Paco, Metian, Marc, Manceau, Alain, Azemard, Sabine, Hédouin, Laetitia, Vassileva, Emilia, Lecchini, David, Fauvelot, Cecile, Swarzenski, Peter W, Glatzel, Pieter, Bustamante, Paco, and Metian, Marc

Abstract

Although fish is an important source of nutrients, including some of the healthiest proteins, long-chain fatty acids, and essential selenium, species at the top of the food chain frequently contain large amounts of toxic mercury (Hg). The provisional tolerable weekly intake (PTWI) of Hg from fish consumption is calculated from the total concentration of Hg and assuming that all Hg is speciated as organic methylmercury (MeHg). Using high energy-resolution X-ray absorption near-edge structure (HR-XANES) spectroscopy, we show that blue marlin (Makaira sp.), a common top predator consumed by humans, contains high concentrations of inorganic Hg(II) complexed as 57 ± 10% Hg-tetraselenolate [Hg(Sec)4] and 43 ± 10% tiemannite (HgSe). The stable Hg–Se chemical bond likely attenuates the bioavailability of Hg and counteracts some of its health hazards to consumers. Thus, monitoring the concentration of MeHg, rather than total Hg, in top predators such as marlin would provide a more robust measure of potential Hg exposure and may be sufficient for food safety controls. The bonding of Hg atoms to four selenocysteine (Sec) residues in the Hg(Sec)4 complex severely depletes the stock of bioavailable Se, and quantification shows that blue marlin is not a chief source of dietary Se essential to selenoenzyme synthesis and activity.

Published
2021
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26. Demethylation of Methylmercury in Bird, Fish, and Earthworm

Author

Manceau, Alain, primary, Bourdineaud, Jean-Paul, additional, Oliveira, Ricardo B., additional, Sarrazin, Sandra L.F., additional, Krabbenhoft, David P., additional, Eagles-Smith, Collin A., additional, Ackerman, Joshua T., additional, Stewart, A. Robin, additional, Ward-Deitrich, Christian, additional, del Castillo Busto, M. Estela, additional, Goenaga-Infante, Heidi, additional, Wack, Aude, additional, Retegan, Marius, additional, Detlefs, Blanka, additional, Glatzel, Pieter, additional, Bustamante, Paco, additional, Nagy, Kathryn L., additional, and Poulin, Brett A., additional

Published
2021
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29. Oldest methanogens from subseafloor hydrothermal environment, South Africa

Author

Cavalazzi, Barbara, primary, Lemelle, Laurence, additional, Simionovici, Alexandre, additional, Cady, Sherry, additional, Russell, Michael, additional, Bailo, Elena, additional, Canteri, Roberto, additional, Enrico, Emanuele, additional, Manceau, Alain, additional, Maris, Assimo, additional, Salome, Murielle, additional, Bouden, Nordine, additional, Tucoulou Tachoueres, Remi, additional, Hofmann, Axel, additional, and Thomassot, Emilie, additional

Published
2021
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31. TEXS: in-vacuum tender x-ray emission spectrometer with eleven Johansson crystal analysers

Author

Rovezzi, Mauro, Harris, Alistair, Detlefs, Blanka, Bohdan, Timothy, Sviazhin, Artem, Santambrogio, Alessandro, Degler, David, Baran, Rafal, Reynier, Benjamin, Crespo, Pedro Noguera, Heyman, Catherine, Van Der Kleij, Hans-Peter, Van Vaerenbergh, Pierre, Marion, Philippe, Vitoux, Hugo, Lapras, Christophe, Verbeni, Roberto, Kocsis, Menhard Menyhert, Manceau, Alain, Glatzel, Pieter, European Synchrotron Radiation Facility (ESRF), Institut des Sciences de la Terre (ISTerre), and Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)

Subjects
Physics::Instrumentation and Detectors, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det]
Abstract

We describe the design and show first results of a large solid angle x-ray emission spectrometer that is optimised for energies between 1.5 keV and 5.5 keV. The spectrometer is based on an array of eleven cylindrically bent Johansson crystal analysers arranged in a point-to-point Rowland circle geometry. The smallest achievable energy bandwidth is smaller than the core hole lifetime broadening of the absorption edges in this energy range. Energy scanning is achieved using an innovative design, maintaining the Rowland circle conditions for all crystals with only four motor motions. The entire spectrometer is encased in a high-vacuum chamber that allows fitting a liquid helium cryostat and provides sufficient space for in situ cells and operando catalysis reactors.

Published
2020

32. Thiols in Natural Organic Matter: Molecular Forms, Acidity, and Reactivity with Mercury(II) from First-Principles Calculations and HR-XANES Spectroscopy

Author

Manceau, Alain, Nagy, Kathryn L., Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), University of Illinois [Chicago] (UIC), University of Illinois System, Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Grenoble Alpes (UGA)-Université Gustave Eiffel-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Department of Earth and Environmental Sciences [Chicago] (EAES), and University of Illinois System-University of Illinois System

Subjects
Sulfurization, kinetics, Gaussian, [CHIM]Chemical Sciences, CCSD(T), thiolation, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, transition state, DOM, metacinnabar
Abstract

International audience; Thiol functional groups in natural organic matter form strong complexes with Hg(II) and other soft metal cations, and therefore are an important component of sulfur and metal cycling in the environment. However, characterizing thiol reactivity is difficult because natural organic molecules are complex both in composition and molecular structure. Here, reactivity was assessed by calculating the Gibbs free energies of thiolation and thiol deprotonation reactions for model structures considered to form during abiotic sulfurization of natural organic matter. Gaussian calculations were performed at the CCSD(T) level of theory. Thiol addition is predicted to be faster by as much as 8 orders of magnitude on unsaturated cyclic structures rich in ketone and ether linkages than on open-chain carbonyl structures. The pKa values of thiols added to carboxyl-rich alicyclic molecules are predicted to be above 10, whereas pKa values of thiols bonded to lignin-derived polyhydroxyphenols are predicted to be between 2 and 6. Reactivity of thiols with Hg(II) was evaluated by monitoring the kinetics of transformation of Hg(SR)2 complexes to nanoparticulate metacinnabar in dissolved organic matter with different chemical compositions under oxic conditions using high energy-resolution X-ray absorption near-edge structure spectroscopy (HR-XANES). The most rapid transformation occurred in the material with the greatest quinone carbon (ketone) and polyphenol contents, consistent with the predicted low pKa values of thiolated ketones near phenolic hydroxyl groups. The slowest transformation occurred in the material with the least amount of cyclic ketone structures, despite having the highest amount of thiols. These results indicate that the sulfur atoms in thiolated ketones are those that are most labile and removed during 2 the alkyl transfer reaction considered to nucleate metacinnabar, and that the concentration of the low-pKa thiols controls the transformation rate.

Published
2019
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39. Chemical Information in the L3X-ray Absorption Spectra of Molybdenum Compounds by High-Energy-Resolution Detection and Density Functional Theory

Author

Svyazhin, Artem, Nalbandyan, Vladimir, Rovezzi, Mauro, Chumakova, Aleksandra, Detlefs, Blanka, Guda, Alexander A., Santambrogio, Alessandro, Manceau, Alain, and Glatzel, Pieter

Abstract

X-ray spectroscopy using high-energy-resolution fluorescence detection (HERFD) has critically increased the information content in X-ray spectra. We extend this technique to the tender X-ray range and present a study at the L3-edge of molybdenum. We show how information on the oxidation state, phase composition, and local environment in molybdenum-based compounds can be obtained by analyzing the HERFD L3X-ray absorption near-edge structure (XANES). We demonstrate that the chemical shift of the L3-edge HERFD spectra follows a parabolic dependence on the oxidation state and show that a qualitative analysis of high-resolution spectra can help to estimate parameters such as distortion of a ligand environment and radial order of atoms around the absorber. In certain cases, the spectra allow disentangling the contributions from bond lengths and angles to the distortion of the ligand polyhedron. Comparison of the high-resolution spectra with theoretical simulations shows that the single-electron approximation is able to reproduce the spectral shape. The results of this work may be useful in every branch of physics, inorganic and organometallic chemistry, catalysis, materials science, biochemistry, and mineralogy where observed changes in performance or chemical properties of Mo-based compounds, accompanied by small changes in spectral shape, are to be related to the details of electronic structure and local atomic environment.

Published
2022
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41. Comment on 'Crystal growth and aggregation in suspensions of δ-MnO 2 nanoparticles: implications for surface reactivity

Author

Manceau, Alain, Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Laboratoire Central des Ponts et Chaussées (LCPC)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Institut des Sciences de la Terre (ISTerre), and Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; Here, it is shown that X-ray diffraction is sensitive to the lognormal distribution of the δ-MnO2 crystallite size and to the strain gradient across the nanosheet. Rigorous modeling of the two effects, which were overlooked by Marafatto et al. (Environ. Sci.: Nano, DOI 10.1039/c7en00817a), is essential to understand the influence of non-uniform microstructures on the physicochemical properties and surface reactivity of nanoparticulate δ-MnO2.

Published
2018
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42. Frontispiece: Mercury(II) Binding to Metallothionein in Mytilus edulis revealed by High Energy-Resolution XANES Spectroscopy

Author

Manceau, Alain, primary, Bustamante, Paco, additional, Haouz, Ahmed, additional, Bourdineaud, Jean Paul, additional, Gonzalez-Rey, Maria, additional, Lemouchi, Cyprien, additional, Gautier-Luneau, Isabelle, additional, Geertsen, Valérie, additional, Barruet, Elodie, additional, Rovezzi, Mauro, additional, Glatzel, Pieter, additional, and Pin, Serge, additional

Published
2019
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43. Mercury(II) Binding to Metallothionein in Mytilus edulis revealed by High Energy‐Resolution XANES Spectroscopy

Author

Manceau, Alain, primary, Bustamante, Paco, additional, Haouz, Ahmed, additional, Bourdineaud, Jean Paul, additional, Gonzalez‐Rey, Maria, additional, Lemouchi, Cyprien, additional, Gautier‐Luneau, Isabelle, additional, Geertsen, Valérie, additional, Barruet, Elodie, additional, Rovezzi, Mauro, additional, Glatzel, Pieter, additional, and Pin, Serge, additional

Published
2018
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47. Analysis of the Major Fe Bearing Mineral Phases in Recent Lake Sediments by EXAFS Spectroscopy

Author

Spadini, Lorenzo, Bott, Markus, Wehrli, Bernhard, Manceau, Alain, Spadini, Lorenzo, Bott, Markus, Wehrli, Bernhard, and Manceau, Alain

Abstract

Extended X-ray absorption fine structure (EXAFS) spectroscopy and chemical analyses were combined to determine the Fe bearing minerals in recent lake sediments from Baldeggersee (Switzerland). The upper section of a laminated sediment core, deposited under eutrophic conditions, was compared to the lower part from an oligotrophic period. Qualitative analysis of FeK EXAFS agreed well with chemical data: In the oligotrophic section Fe(II)-O and Fe(III)-O specieswere present, whereas a significant fraction of Fe(II)-S sulfides was strongly indicated in the eutrophic part. A statistical analysis was performed by least square fitting of normalized reference spectra. The set of reference minerals included Fe(III) oxides and Fe(II) sulfides, carbonates and phosphates. In the oligotrophic regime no satisfying fit was obtained using the set of reference spectra, indicating that siderite (FeCO3) was not present in a significant amount in these carbonate-rich sediments. Simulated EXAFS spectra for a(Cax, Fe1-x)CO3solid solution allowed reconstructing the specificfeatures of the experimental spectra, suggesting that this phase was the dominant Fe carrier in the oligotrophic section of the core. In the eutrophic part, mackinawite was positively identified and represented the dominant Fe(II) sulfide phase. This finding agreed with chemical extraction, which indicated that18-40 mol% of Fe was contained in the acid volatile iron sulfide fraction. EXAFS spectra of the eutrophic section were best fitted by considering the admixture of mackinawite and the Fe-Ca carbonate phase inferred to be predominant in the oligotrophic regime

Published
2018

48. Acute Toxicity of Divalent Mercury to Bacteria Explained by the Formation of Dicysteinate and Tetracysteinate Complexes Bound to Proteins in Escherichia coliand Bacillus subtilis

Author

Manceau, Alain, Nagy, Kathryn L., Glatzel, Pieter, and Bourdineaud, Jean-Paul

Abstract

Bacteria are the most abundant organisms on Earth and also the major life form affected by mercury (Hg) poisoning in aquatic and terrestrial food webs. In this study, we applied high energy-resolution X-ray absorption near edge structure (HR-XANES) spectroscopy to bacteria with intracellular concentrations of Hg as low as 0.7 ng/mg (ppm) for identifying the intracellular molecular forms and trafficking pathways of Hg in bacteria at environmentally relevant concentrations. Gram-positive Bacillus subtilisand Gram-negative Escherichia coliwere exposed to three Hg species: HgCl2, Hg–dicysteinate (Hg(Cys)2), and Hg–dithioglycolate (Hg(TGA)2). In all cases, Hg was transformed into new two- and four-coordinate cysteinate complexes, interpreted to be bound, respectively, to the consensus metal-binding CXXC motif and zinc finger domains of proteins, with glutathione acting as a transfer ligand. Replacement of zinc cofactors essential to gene regulatory proteins with Hg would inhibit vital functions such as DNA transcription and repair and is suggested to be a main cause of Hg genotoxicity.

Published
2021
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