Laboratoire Archéomatériaux et Prévision de l'Altération

UNLABELLED: Hepatocellular carcinoma (HCC) is the major primary liver cancer. Glypican-3 (GPC3), one of the most abnormally expressed genes in HCC, participates in liver carcinogenesis. Based on data showing that GPC3 expression is posttranscriptionally altered in HCC cells compared to primary hepatocytes, we investigated the implication of microRNAs (miRNAs) in GPC3 overexpression and HCC. To identify GPC3-regulating miRNAs, we developed a dual-fluorescence FunREG (functional, integrated, and quantitative method to measure posttranscriptional regulations) system that allowed us to screen a library of 876 individual miRNAs. Expression of candidate miRNAs and that of GPC3 messenger RNA (mRNA) was measured in 21 nontumoral liver and 112 HCC samples. We then characterized the phenotypic consequences of modulating expression of one candidate miRNA in HuH7 cells and deciphered the molecular mechanism by which this miRNA controls the posttranscriptional regulation of GPC3. We identified five miRNAs targeting GPC3 3'-untranslated region (UTR) and regulating its expression about the 876 tested. Whereas miR-96 and its paralog miR-1271 repressed GPC3 expression, miR-129-1-3p, miR-1291, and miR-1303 had an inducible effect. We report that miR-1271 expression is down-regulated in HCC tumor samples and inversely correlates with GPC3 mRNA expression in a particular subgroup of HCC. We also report that miR-1271 inhibits the growth of HCC cells in a GPC3-dependent manner and induces cell death. CONCLUSION: Using a functional screen, we found that miR-96, miR-129-1-3p, miR-1271, miR-1291, and miR-1303 differentially control GPC3 expression in HCC cells. In a subgroup of HCC, the up-regulation of GPC3 was associated with a concomitant down-regulation of its repressor miR-1271. Therefore, we propose that GPC3 overexpression and its associated oncogenic effects are linked to the down-regulation of miR-1271 in HCC.

Abstract Raman structural imaging can extract original information in order to answer new questions raised in the recent studies on iron and low alloy steel corrosion. Up to now, this technique has allowed the extraction of the qualitative distribution of the compounds constituting the corrosion product layers. We propose here a methodology to extract quantitative parameters from Raman hyperspectral maps, executed by a home‐developed software: LADIR‐CAT. Specifically developed for iron corrosion quantitative component imaging, the approach and program operation are described. The LADIR‐CAT is applied on ancient corroded iron samples originating from the Amiens cathedral (France) to establish the description and the composition of the corrosion system through quantitative compound imaging. Copyright © 2010 John Wiley & Sons, Ltd.

The knowledge of the long-term behavior of nuclear waste in anticipation of ultimate disposal in a deep geological formation is of prime importance in a waste management strategy. If phenomenological models have been developed to predict the long-term behavior of these materials, validating these models remains a challenge, when considering the time scale of radioactive decay of radionuclides of environmental concern, typically 10 4 –10 5 yrs. Here we show how natural or archaeological analogues provide critical constraints not only on the phenomenology of glass alteration and the mechanisms involved, but also on the ability of experimental short-term data to predict long-term alteration in complex environments.

Abstract In several contexts such as cultural heritage, oil and gas or nuclear waste disposal, the long‐term corrosion mechanisms of iron in anoxic soils are studied. For this purpose, corrosion layers formed on ferrous archaeological artefacts from the site of Glinet (16th century, Normandy, France) were characterised. The main phases identified are siderite (FeCO 3 ), chukanovite (iron hydroxycarbonate: Fe 2 (OH) 2 CO 3 and magnetite (Fe 3 O 4 ). In order to provide reliable Raman references for further studies on carbonated systems, the iron hydroxycarbonate (chukanovite) was synthesised on iron discs. The corrosion mechanisms were investigated by re‐corroding the archaeological samples in a deuterated solution. Raman characterisation on cross sections inside the layer revealed the presence of deuterated chukanovite, allowing the deuterium tracing of the spreading of the corrosion. A set of chukanovite samples was synthesised with various D/H ratios. Using these reference data, the proportion of deuterated chukanovite in re‐corroded artefacts was evaluated, and the corrosion rate was estimated as less than 1.6 µm/year. Copyright © 2010 John Wiley & Sons, Ltd.

Ce livre est le fruit d’un colloque international tenu au Musée des arts et métiers grâce au soutien de nombreuses institutions internationales et nationales, en particulier le CNRS, le CDHTE/Cnam et l’Université Paris 8. Il a réuni des historiens, des archéologues et des archéomètres autour de ce matériau complexe qu’est l’acier avant l’ère de la production industrielle massive. Le cadre chronologique est donc celui des longues durées, de l’Antiquité au premier XIXe siècle. L’ouvrage s’articule autour de trois thèmes. Il s’ouvre par des définitions de l’acier en un temps où ce matériau n’avait pas été encore analysé selon les critères scientifiques contemporains. Dans ce domaine, l’apport récent de l’archéométrie et de l’archéologie, confronté aux terminologies d’usage comme aux traités savants, d’Aristote à Réaumur, offre une compréhension diachronique, tant scientifique que technique, d’un matériau dont la singularité frappe ses usagers depuis l’Antiquité. L’ouvrage se poursuit par une présentation des procédés de fabrications. Leur diversité illustra le foisonnement des modes opératoires qui parfois coexistent malgré des ruptures techniques majeures. Le Moyen Âge et les Temps modernes, périodes de différenciation des matières, des produits et des techniques, ont concentré l’attention des auteurs. Enfin, une large place a été consacrée aux marchés et aux usages de l’acier. Les différents procédés répondent à des logiques d’adaptation des matériaux aux besoins, aux contraintes et aux opportunités commerciales. Ouvrir le dossier de l’acier avant Bessemer, c’est finalement poser de façon neuve la question de l’entreprise et de la rationalité technique

Abstract The aim of this paper is to understand what the chemical influence of the concrete on the corrosion form present is, on rebars embedded for tens or hundreds years. Therefore, metal/concrete interface of samples coming from two French Historical Monuments has been characterized: ‘ Bourse du Travail ’, Bordeaux, 80 years old and ‘ Maison du Brésil de la Cité Internationale de Paris ’, 50 years old. The collected samples have been observed on transverse section in order to observe the whole corrosion system (metal/corrosion products/concrete). Morphology, elementary composition and structure have been studied with complementary analytical approaches (optical microscope, scanning electron microscope coupled to energy dispersive spectroscopy and Raman microspectroscopy). Thus, a fine description of the corrosion scales formed on the metallic rebars can be schematized. On the basis of these results, mechanisms hypotheses are proposed in the discussion.

Architecture represents key evidence of dynastic practice and change in the archaeological world. Chronologies for many important buildings and sequences, including the iconic temples of medieval Angkor in Cambodia, are based solely on indirect associations from inscriptions and architectural styles. The Baphuon temple, one of the last major buildings in Angkor without textual or scientifically-derived chronological evidence, is crucial both for the context and date of its construction and the period when its western façade was modified into a unique, gigantic Reclining Buddha. Its construction was part of a major dynastic change and florescence of the Hindu-Mahayana Buddhist state and the modification is the key evidence of Theravada Buddhist power after Angkor's decline in the 15th century. Using a newly-developed approach based on AMS radiocarbon dating to directly date four iron crampons integrated into the structure we present the first direct evidence for the history of the Baphuon. Comprehensive study of ferrous elements shows that both construction and modification were critically earlier than expected. The Baphuon can now be considered as the major temple associated with the imperial reformations and territorial consolidation of Suryavarman I (1010-1050 AD) for whom no previous building to legitimize his reign could be identified. The Theravada Buddhist modification is a hundred years prior to the conventional 16th century estimation and is not associated with renewed use of Angkor. Instead it relates to the enigmatic Ayutthayan occupation of Angkor in the 1430s and 40s during a major period of climatic instability. Accurately dating iron with relatively low carbon content is a decisive step to test long-standing assumptions about architectural histories and political processes for states that incorporated iron into buildings (e.g., Ancient Greece, medieval India). Furthermore, this new approach has the potential to revise chronologies related to iron consumption practices since the origins of ferrous metallurgy three millennia ago.

Abstract In this paper investigations into the formation of specific corrosion products during the process of chloride induced corrosion of steel in concrete are presented. The extension of corrosion products within concrete was established by means of X‐ray tomography analyses. Then a detailed analysis of the nature of corrosion products has been conducted by means of Raman micro‐spectroscopy and energy dispersive spectroscopy. Results emphasize two different corrosion patterns. The first one is composed of shallow cavities, where mostly magnetite and goethite were identified, traducing aerated to moderate aerated conditions in these media. The second pattern was identified as deep, needle‐like pits, where chlorinated‐iron‐oxides phases were present associated with more or less important chloride enrichments. The presence of these particular species is indicating low redox and low pH conditions within these pits.

The basic functional equations for connected and 2-connnected graphs can be traced back to the statistical physicists Mayer and Husimi. They play an essential role in establishing rigorously the virial expansion for imperfect gases. We first review these functional equations, putting the emphasis on the structural relationships between the various classes of graphs. We then investigate the problem of enumerating some classes of connected graphs all of whose 2-connected components (blocks) are contained in a given class $B$. Included are the species of Husimi graphs ($B =$ "complete graphs"), cacti ($B =$ "unoriented cycles"), and oriented cacti ($B =$ "oriented cycles"). For each of these, we address the question of their labelled and unlabelled enumeration, according (or not) to their block-size distributions. Finally we discuss the molecular expansion of these species. It consists of a descriptive classification of the unlabelled structures in terms of elementary species, from which all their symmetries can be deduced.

AbstractIn the context of the in situ conservation and preservation of archaeological artefacts, the long term corrosion mechanisms of iron in anoxic soils are studied. To this purpose, a first step is the characterisation of the corrosion layers formed on archaeological artefacts provided from the archaeological site of Glinet (the sixteenth, Normandy, France). On all the corrosion systems formed on artefacts, the main phases constitutive of the corrosion layer are siderite (FeCO3), an iron carbonate containing hydroxide groups [probably chukanovite Fe2(OH)2CO3] and magnetite (Fe3O4). Furthermore, the arrangement of these phases reveals three corrosion distribution types with corresponding corrosion pattern diagrams.Keywords: ANOXIC CORROSIONARCHAEOLOGICAL ARTEFACTSCORROSION LAYER CHARACTERISATIONMICROBEAM TECHNIQUES

Abstract

In the present work, the authors tried to establish degradation indices for heritage ferrous artefacts, especially those used in ancient buildings and submitted to indoor atmospheric corrosion. The authors focused on the site of the Amiens Cathedral in the north of France. Samples coming from this reference site were carefully characterised in order to identify the different phases constituting the corrosion scale. The scale consists in a matrix of iron oxyhydroxide goethite embedded with several ferrihydrite marblings. Other phases such as lepidocrocite and akaganeite are scarcely present in the external part of the corrosion scale. Moreover, electrochemical measurements on both references and ancient samples enable to define the reduction reactive phases. From the nature of these phases and their localisation, two degradation indices were defined to evaluate rust reactivity. Finally, a curve that links these two factors is proposed as a first step towards a corrosion diagnosis.

Two tests of iron corrosion in compacted clay and clay slurry were performed for several years.

Abstract

Improvement of an LA-ICP-MS methodology tailored to quantify trace elements in small slag inclusions and application to armour for provenance study.

BACKGROUND: Autoimmune demyelinating diseases (ADD) are a major cause of neurological disability due to autoreactive cellular and humoral immune responses against brain antigens. A cure for chronic ADD could be obtained by appropriate immunomodulation. METHODS: lymphocytes and anti-MOG IgG. For immunotherapy, we used a recombinant antibody (Ab) directed against the dendritic cell-asialoglycoprotein receptor (DC-ASGPR) fused either to MOG or a control antigen PSA (prostate-specific antigen). FINDINGS: regulatory lymphocytes and favoured an upsurge in systemic TGFβ and IL-8 upon rhMOG re-administration in vivo. INTERPRETATION: We show that the delivery of an anti-DC-ASGPR-MOG allows antigen-specific adaptive immune modulation to prevent the breach of immune tolerance to MOG. Our findings pave the way for therapeutic vaccines for long-lasting remission to grave encephalomyelitis with identified autoantigens, such as ADD associated with anti-MOG autoantibodies. FUND: Work supported by the French ANR (ANR-11-INBS-0008 and ANR-10-EQPX-02-01), NIH (NIH 1 R01 AI 105066), the Baylor Scott and White Healthcare System funding and Roche Research Collaborative grants.

Carbon steel coupons were buried in a specific low-pH cement grout designed for radioactive waste disposal and left 6 months in anoxic conditions at 80 °C. The corrosion product layers were analyzed by µ-Raman spectroscopy, XRD, and SEM. They proved to be mainly composed of iron sulfides, with magnetite as a minor phase, mixed with components of the grout. Average corrosion rates were estimated by weight loss measurements between 3 and 6 µm yr−1. Corrosion profiles revealed local degradations with a depth up to 10 µm. It is assumed that the heterogeneity of the corrosion product layer, mainly composed of conductive compounds (FeS, Fe3S4, and Fe3O4), promotes the persistence of corrosion cells that may lead to locally aggravated degradations of the metal. New cement grouts, characterized by a slightly higher pH and a lower sulfide concentration, should then be designed for the considered application.

Oxygen trapped during the operational phase in disposal cells of an underground radioactive waste repository is often considered to be quickly consumed, notably by corrosion of metallic materials or reducing microorganisms. This would lead to anoxic conditions in most of each disposal cell. In addition to this, a shift from anoxic to oxic conditions could not be excluded locally in disposal cells after their closure due to the ventilation in handling drifts that could contribute to the regeneration of oxygen at the head of each disposal cell. The impact of these transient phases on corrosion processes may affect the confinement properties of metallic components and should thus be assessed. To this end, ferrous archaeological analogues are studied. The present paper focuses on the characterisation of nails that have undergone such transient phases. First, a sample exposed for several hundred years to an aerated environment and then to an anoxic carbonated environment in laboratory for 3 years has been analysed. Corrosion layers after the oxic phase contain mostly oxihydroxides (such as goethite) and some layers perpendicular or parallel to the interface, which is in good agreement with an aerated corrosion. After 3 years under anoxic conditions, the main phase of the corrosion layer is siderite. Second, a sample exposed to an anoxic environment for several hundred years has been immersed in an aerated solution for 5 weeks. The main phases of the corrosion layer after the anoxic phase are iron carbonates and a goethite layer formed on the outer part of the corrosion layer after the immersion in an aerated solution. In both cases, the formation of new phases in the corrosion layer is in good agreement with predictions of thermodynamic modelling based on the respective environmental conditions.

The study of iron reinforcements used in the construction of Notre-Dame de Paris offers a glimpse into the innovation that took place on this building site in the mid-12th century, adapting metal to create a novel architecture. The restoration of the monument after the 2019 fire offered unique possibilities to investigate its iron armatures and to sample 12 iron staples from different locations (tribunes, nave aisles and upper walls). Six of them were dated thanks to the development of an innovative methodology based on radiocarbon dating. They reveal that Notre-Dame is the first known Gothic cathedral where iron was massively used as a proper construction material to bind stones throughout its entire construction, leading to a better understanding of the master masons' thinking. Moreover, a metallographic study and slag inclusion chemical analyses of the staples provide the first study of iron supply for a great medieval Parisian building yard, renewing our understanding of iron circulation, trade and forging in the 12th and 13th century capital of the French kingdom. The highlighting of numerous welds in all iron staples and the multiple provenances sheds light on the activity of the iron market in this major medieval European city and the nature of the goods that circulated, and questions the possible importance of recycling.

La démarche expérimentale en numismatique antique n'est pas nouvelle, D. G. Sellwood, dans les années 1950, mena une série d'expérimentations qui constitue encore aujourd'hui une référence. L'approche de notre groupe se voulait plus globale, traitant des différents aspects de la chaîne opératoire qui conduit du métal à la monnaie. 12 281 monnaies ont été frappées lors des deux saisons d'expérimentations, ce qui permet de fournir de nouveaux résultats sur les méthodes de fabrication des flans ou bien sur l'usure des coins monétaires. L'incapacité de notre équipe à calibrer le poids des flans, par exemple, remet en cause les hypothèses formulées sur le mode opératoire des monnayeurs des ateliers grecs. Le principal objectif de la reconstitution de l'atelier monétaire était de frapper un maximum de monnaies afin d'étudier l'usure des coins monétaires. Il en ressort qu'un coin de droit pouvait connaître une productivité différente selon la taille des flans, l'expérience de l'équipe et le métal utilisé. Les résultats permettent tout de même de fixer sa production moyenne dans une fourchette qui pourrait se situer entre 10 000 et 15 000 exemplaires. D'autres expérimentations à venir permettront, nous l'espérons, de fournir de nouvelles données et peut-être d'ajuster nos estimations.