CNRS Laboratory of Molecular and Structural Archaeology

Paris, France

CNRS Laboratory of Molecular and Structural Archaeology

Paris, France
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Akouche M.,CNRS Surface Science Lab | Jaber M.,CNRS Laboratory of Molecular and Structural Archaeology | Maurel M.-C.,CNRS Systematics, Biodiversity and Evolution Institute | Lambert J.-F.,CNRS Surface Science Lab | Georgelin T.,CNRS Surface Science Lab
Angewandte Chemie - International Edition | Year: 2017

In this contribution, we report the formation under prebiotic conditions of phosphoribosyl pyrophosphate (PRPP) as a molecular precursor in the one-pot synthesis of a canonical nucleotide, namely adenosine monophosphate (AMP) from its building blocks (KH2PO4 or Pi, adenine, and d-ribose), on a fumed silica surface. The on-the-rocks approach has been successfully applied to the simultaneous phosphorylation and glycosylation of ribose. The one-pot formation mechanism of AMP involves a two-step pathway via an activated intermediate, namely PRPP, obtained by multiple ribose phosphorylations upon mild thermal activation. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Salnaia N.,Russian Academy of Sciences | Gallet Y.,University Paris Diderot | Genevey A.,CNRS Laboratory of Molecular and Structural Archaeology | Antipov I.,Saint Petersburg State University
Physics of the Earth and Planetary Interiors | Year: 2017

Reconstructing the secular variation of Europe's geomagnetic field over the past millennium is challenging because of the lack of recently acquired archeomagnetic data from Western Russia. In this paper, we report on nine new archeointensity values obtained from groups of brick fragments sampled in Novgorod (North-Western Russia) and its vicinities. These fragments were collected from churches whose precise ages range from the beginning of the 12th century to the end of the 17th century AD. All the archeointensity measurements were carried out using the Triaxe experimental protocol, which takes into account the thermoremanent magnetization (TRM) anisotropy effect. Intensity determinations were performed using fast and slow cooling rates for laboratory-TRM acquisition. The results confirm that the Triaxe protocol overcomes the TRM cooling rate dependence. The new data shows that geomagnetic field intensities in North-Western Russia have decreased in the past millennium. Comparisons were made with other data previously obtained in Western Europe, the Balkans and Russia, as well as with intensity values expected in Novgorod from global geomagnetic field models. These comparisons yielded three main results: 1) The new archeointensity data do not show the occurrence of large intensity variations in North-Western Russia, as those observed in the Balkan dataset. Conversely, they appear more compatible with Western European results, which suggests a limited non-dipole field effect across Europe during the past millennium; 2) Our data are weaker than the intensity values expected in Novgorod from the available global geomagnetic field models. This suggests that the field models are inaccurate for the Novgorod area; 3) A constant linear decrease of the geocentric axial dipole moment since 1600 AD does not appear compatible with our younger data. © 2017 Elsevier B.V.

Pichon L.,University Pierre and Marie Curie | Moignard B.,University Pierre and Marie Curie | Lemasson Q.,University Pierre and Marie Curie | Pacheco C.,University Pierre and Marie Curie | And 2 more authors.
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2014

The New AGLAE external beamline provides analytical data for the understanding of the structure of archaeological and artistic objects, their composition, properties, and changes over time. One of the objectives of this project is to design and set up a new non-invasive acquisition system increasing the quality of the X-ray spectra and reducing the beam current on sensitive materials from work of art. To that end, the surface and the number of PIXE detectors have been increased to implement a cluster of SDD detectors. This can also provide the possibility to accomplish large and/or fast maps on artifacts with a scanning of the beam on the sample. During the mapping, a multi-parameter system saves each event from X-ray, gamma and particle detectors, simultaneously with the X and Y positions of the beam on the sample. To process the data, different softwares have been developed or updated. A first example on a decorated medieval shard highlights the perspectives of the technique. © 2013 Elsevier Ltd. All rights reserved.

Mass J.L.,Scientific Research and Analysis Laboratory | Opila R.,University of Delaware | Buckley B.,Barnes Foundation | Cotte M.,European Synchrotron Radiation Facility | And 3 more authors.
Applied Physics A: Materials Science and Processing | Year: 2013

Evidence for the alteration of the yellow paints in Henri Matisse's Le Bonheur de vivre (1905-1906, The Barnes Foundation) has been observed since the 1990s. The changes in this iconic work of Matisse's Fauvist period include lightening, darkening, and flaking of the yellow paints. Handheld X-ray fluorescence (XRF) and multispectral imaging surveys reveal that the degradation is confined to cadmium yellow (CdS) paints. The discoloration of cadmium yellow paints in Impressionist, Post-Impressionist and early modernist work from the 1880s through the 1920s has been ascribed to the photo-oxidative degradation of CdS. Preliminary investigations of the degraded yellow paints in this work involved Cd LIII-edge X-ray Absorption Near Edge Spectroscopy (XANES) at the Stanford Synchrotron Radiation Light Source (SSRL Menlo Park, California) and Scanning Electron Microscopy-energy dispersive X-ray analysis (SEM-EDS) at the Winterthur Museum Scientific Research and Analysis Laboratory. To determine if the visual changes in the paints did in fact indicate photo-oxidative degradation and if different chemistries could be observed for the lightened versus darkened regions, synchrotron radiation-micro Fourier Transform InfraRed (SR-μFTIR) spectroscopy, X-ray Fluorescence (SR-μXRF) mapping and micro X-ray Absorption Near Edge Spectroscopy (μXANES) mapping at the Cd LIII-edge of the altered paint cross-sections were carried out at the European synchrotron radiation facility (ESRF, Grenoble, France) beamline ID-21. The goal is to elucidate the discoloration mechanisms observed in the paint using elemental and speciation mapping. The μXANES mapping and SR-FTIR imaging showed a substantial enrichment of CdCO3 in the off-white surface crust of the faded/discolored CdS paint. This suggests that the CdCO3 is present as an insoluble photodegradation product rather than solely a paint filler or starting reagent. Additionally, oxalates and sulfates were found to be concentrated at the alteration surface. © 2012 Springer-Verlag Berlin Heidelberg.

Radtke M.,BAM Federal Institute of Materials Research and Testing | Reiche I.,CNRS Laboratory of Molecular and Structural Archaeology | Reinholz U.,BAM Federal Institute of Materials Research and Testing | Riesemeier H.,BAM Federal Institute of Materials Research and Testing | Guerra M.F.,CNRS Laboratory of Molecular and Structural Archaeology
Analytical Chemistry | Year: 2013

Fingerprinting ancient gold work requires the use of nondestructive techniques with high spatial resolution (down to 25 μm) and good detection limits (micrograms per gram level). In this work experimental setups and protocols for synchrotron radiation induced X-ray fluorescence (SRXRF) at the BAMline of the Berlin electron storage ring company for synchrotron radiation (BESSY) in Berlin for the measurement of characteristic trace elements of gold are compared considering the difficulties, shown in previous works, connected to the quantification of Pt. The best experimental conditions and calculation methods were achieved by using an excitation energy of 11.58 keV, a silicon drift chamber detector (SDD) detector, and pure element reference standards. A detection limit of 3 μg/g has been reached. This newly developed method was successfully applied to provenancing the Xiongnu gold from the Gol Mod necropolis, excavated under the aegis of the United Nations Educational, Scientific and Cultural Organization (UNESCO). The composition of the base alloys and the presence of Pt and Sn showed that, contrary to what is expected, the gold foils from the first powerful empire of the steppes along the Great Wall were produced with alluvial gold from local placer deposits located in Zaamar, Boroo, and in the Selenga River. © 2012 American Chemical Society.

Buleon A.,French National Institute for Agricultural Research | Cotte M.,European Synchrotron Radiation Facility | Cotte M.,CNRS Laboratory of Molecular and Structural Archaeology | Putaux J.-L.,French National Center for Scientific Research | And 2 more authors.
Biochimica et Biophysica Acta - General Subjects | Year: 2014

Background Native starch accumulates as granules containing two glucose polymers: amylose and amylopectin. Phosphate (0.2-0.5%) and proteins (0.1-0.7%) are also present in some starches. Phosphate groups play a major role in starch metabolism while granule-bound starch synthase 1 (GBSS1) which represents up to 95% of the proteins bound to the granule is responsible for amylose biosynthesis. Methods Synchrotron micro-X-ray fluorescence (μXRF) was used for the first time for high-resolution mapping of GBSS1 and phosphate groups based on the XRF signal of sulfur (S) and phosphorus (P), respectively. Wild-type starches were studied as well as their related mutants lacking GBSS1 or starch-phosphorylating enzyme. Results Wild-type potato and maize starch exhibited high level of phosphorylation and high content of sulfur respectively when compared to mutant potato starch lacking glucan water dikinase (GWD) and mutant maize starch lacking GBSS1. Phosphate groups are mostly present at the periphery of wild-type potato starch granules, and spread all over the granule in the amylose-free mutant. P and S XRF were also measured within single small starch granules from Arabidopsis or Chlamydomonas not exceeding 3-5 μm in diameter. Conclusions Imaging GBSS1 (by S mapping) in potato starch sections showed that the antisense technique suppresses the expression of GBSS1 during biosynthesis. P mapping confirmed that amylose is mostly present in the center of the granule, which had been suggested before. General significance μXRF is a potentially powerful technique to analyze the minor constituents of starch and understand starch structure/properties or biosynthesis by the use of selected genetic backgrounds. © 2013 Elsevier B.V.

Benseny-Cases N.,European Synchrotron Radiation Facility | Benseny-Cases N.,University of Leeds | Klementieva O.,University of Barcelona | Klementieva O.,CIBER ISCIII | And 6 more authors.
Analytical Chemistry | Year: 2014

(Figure Presented) Amyloid peptides are the main component of one of the characteristic pathological hallmarks of Alzheimer's disease (AD): senile plaques. According to the amyloid cascade hypothesis, amyloid peptides may play a central role in the sequence of events that leads to neurodegeneration. However, there are other factors, such as oxidative stress, that may be crucial for the development of the disease. In the present paper, we show that it is possible, by using Fourier tranform infrared (FTIR) microscopy, to co-localize amyloid deposits and lipid peroxidation in tissue slides from patients affected by Alzheimer' s disease. Plaques and lipids can be analyzed in the same sample, making use of the characteristic infrared bands for peptide aggregation and lipid oxidation. The results show that, in samples from patients diagnosed with AD, the plaques and their immediate surroundings are always characterized by the presence of oxidized lipids. As for samples from non-AD individuals, those without amyloid plaques show a lower level of lipid oxidation than AD individuals. However, it is known that plaques can be detected in the brains of some non-AD individuals. Our results show that, in such cases, the lipid in the plaques and their surroundings display oxidation levels that are similar to those of tissues with no plaques. These results point to lipid oxidation as a possible key factor in the path that goes from showing the typical neurophatological hallmarks to suffering from dementia. In this process, the oxidative power of the amyloid peptide, possibly in the form of nonfibrillar aggregates, could play a central role. © 2014 American Chemical Society.

Spadavecchia J.,CNRS Surface Science Lab | Apchain E.,CNRS Laboratory of Molecular and Structural Archaeology | Alberic M.,CNRS Laboratory of Molecular and Structural Archaeology | Fontan E.,Musee du Louvre | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2014

A one-step method is reported to synthesize hybrid gold nanoparticles (AuNPs) by reduction of HAuCl4 in acetic solution in the presence of collagen (Col), dicarboxylic acid-terminated polyethylene glycol (PEG), and cetyltetrammonium bromide (CTAB) mixed with hydoxyapatite (HAP) as surfactants. Such formation process of AuNPs was shown to be responsible for purple stains naturally formed on Egyptianizing archaeological gilded ivories from 8th BC Syria. The understanding of this formation mechanism, which most likely involves a step with hybrid AuNPs, allows the establishing of an authenticity marker of ancient gold-plated ivories. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pouyet E.,European Synchrotron Radiation Facility | Lluveras-Tenorio A.,Consortium for Science and Technology of Materials | Nevin A.,CNR Institute for Photonics and Nanotechnologies | Saviello D.,Polytechnic of Milan | And 3 more authors.
Analytica Chimica Acta | Year: 2014

For more than a century, the analyses of painting fragments have been carried out mainly through the preparation of thick resin-embedded cross-sections. Taking into account the development of innovative micro-analytical imaging techniques, alternatives to this standard preparation method are considered. Consequently, dedicated efforts are required to develop preparation protocols limiting the risks of chemical interferences (solubilisation, reduction/oxidation or other reactions) which modify the sample during its preparation, as well as the risks of analytical interferences (overlap of detected signals coming from the sample and from materials used in the preparation). This study focuses particularly on the preparation of thin-sections (1-20. μm) for single or combined fourier transform infrared (FTIR) spectroscopy and X-ray 2D micro-analysis. A few strategies specially developed for the μFTIR analysis of painting cross-sections have already been reported and their potential extrapolation to the preparation of thin-sections is discussed. In addition, we propose two new specific methods: (i) the first is based on a free-embedding approach, ensuring a complete chemical and analytical neutrality. It is illustrated through application on polymeric design objects corpus; (ii) the second is based on a barrier coating approach which strengthens the sample and avoids the penetration of the resin into the sample. The barrier coating investigated is a silver chloride salt, an infrared transparent material, which remains malleable and soft after pellet compression, enabling microtoming. This last method was successfully applied to the preparation of a fragment from a gilded Chinese sculpture (15th C.) and was used to unravel a unique complex stratigraphy when combining μFTIR and μXRF. © 2014 Elsevier B.V.

Lebon M.,French Natural History Museum | Zazzo A.,French Natural History Museum | Reiche I.,CNRS Laboratory of Molecular and Structural Archaeology | Reiche I.,Rathgen Research Laboratory
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2014

Bones and teeth are highly hierarchically structured and hererogeneous materials, and post mortem processes can reinforce this heterogeneity. It is therefore important to consider this heterogeneity to better understand diagenetic processes. In this study, ATR-FTIR mapping was applied to several heated and un-heated archaeological samples, and to similar modern references in order to test the potential of this method. ATR-FTIR mapping can provide spatially resolved information on alteration state of mineral and organic matter. This technique allowed to describe the spatial distribution of organic and mineral matter preservation in unheated Palaeolithic bones (Bize-Tournal, France) characterized by a better preservation in the centre of the cortical bone. Spatial variations in the chemical composition of an archaeological heated bone (Abri Pataud, France) compared to a modern reference suggested taphonomical uptake of carbonate in the most external part. This pattern could correspond to a process of re-carbonatation of the calcined mineral matter in the outermost part of the sample due to combustion in a CO2 rich atmosphere. FTIR-ATR is a powerful tool that allows for identifying and characterizing local heterogeneities in bone preservation. This technique open new prospects to reconstruct the taphonomical history of ancient samples. © 2014 Elsevier B.V.

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