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Iron and Heritage in Cambodia: A Radiocarbon Dating Approach Between Accelerator Mass Spectrometry, Material Analysis, and Material Culture
No full textInternational audienceRadiocarbon dating by accelerator mass spectrometry (AMS) is an effective method for determining the age of carbon-containing objects, such as organic artifacts. By directly measuring the number of 14C atoms in very small samples, AMS provides precise results even for samples with minimal carbon content. Recent advancements in this technique have broadened its application to the analysis of micro-samples, opening new avenues for archaeological research. Today, it is possible to detect residual 14C traces in ancient ferrous metals, which were used to create a wide range of objects in ancient societies. Iron played a central role in the production of various items within the Khmer Empire (9th-14th centuries). It was used in the form of iron clamps for the temples of Angkor, iron reinforcements in bronze objects, tools, weapons, and a range of everyday items. Many of these archaeological artifacts are accessible through excavations, architectural restoration projects, and museum collections. The ability to date these objects—and, more specifically, to determine the timing of metal production—offers crucial chronological insights into production methods, the organization of production, manufacturing processes, usage patterns, and the networks of metal distribution and circulation. This approach is built on a solid methodological framework (Leroy et al. 2015), focused on identifying the material-specific characteristics of the objects in question. How were these objects made, and where did the metal originate? By combining various analytical techniques, particle accelerator technology reveals the chronological context of these production and manufacturing events. In this context, several series of iron objects from Cambodia have been studied to document the organization of iron production and supply networks (IRANGKOR project). The analysis of a series of iron clamps from temples in Angkor (col. with ASPARA authority), has provided crucial dating, which, in some cases, helps to clarify the periods and phases of construction of these structures. Additionally, a selection of objects from the collection of the National Museum of Cambodia, some with uncertain provenance, were also studied, thus making a significant contribution to the advancement of current knowledge. The analyzed objects and samples exhibit a diversity of shapes and compositions, requiring the implementation of a tailored sampling and analysis protocol. This study outlines the key steps of this approach and synthesizes the results obtained for several iconic monuments of the Angkor complex, as well as objects from museum collections, while providing a broader overview of the discoveries made to date
Antimicrobial properties of surgical sutures decorated with PtAu/Pd nanoparticles prepared by sputtering on liquids
No full textInternational audienceColloidal suspensions of nanoparticles were produced by sequentially sputtering PtAu and Pd targets on polyethylene glycol liquid. Commercial suture wires were then immersed in the colloidal suspensions in an attempt to have them decorated with the trimetallic nanoparticles. The biocidal effect of the treated wires was tested against Staphylococcus aureus and Escherichia col
Le fractionnement des monnaies en Gaule et dans les Germanies, de la Tène finale au Haut Empire
No full textInternational audienceCette communication se propose de retracer l’apparition du phénomène du fractionnement du numéraire dans l’espace gaulois et germanique, depuis la Protohistoire jusqu’au Principat, en se fondant sur les données archéologiques et stratigraphiques disponibles. La pratique est connue à la fin de La Tène mais n’a visiblement pas la même signification qu’à la période romaine : c’est seulement après la conquête qu’elle devient courante, et pour une brève période seulement puisque le fractionnement des monnaies caractérise principalement l’époque augustéenne et qui disparaît presque complètement après le milieu du Ier s. ap. J.-C. Il semble donc s’agir d’un procédé importé du sud des Alpes, dont la mise en pratique abondante mais brève doit peut-être être mise en relation avec les conditions socio-économiques de l’espace gaulois à cette période.[Actes du colloque, Università Cattolica del Sacro Cuore, Milan, 16 et 17 septembre 2019, Rome, Edizioni Quasar, 2025.
FTIR characterisation of chondroitin sulfate E (CS-E) di-, tetra-, and hexasaccharide derivatives and their biotinylated or reducing conjugates
No full textInternational audienceSulfated glycosaminoglycans (GAGs), namely, chondroitin sulfate (CS), dermatan sulfate, keratan sulfate, heparin, and heparan sulfate, are linear complex polysaccharides that are covalently attached to core proteins to form proteoglycans. They are present at the cell surface and in the extracellular matrix and play a key role in the regulation of cellular microenvironmental effectors. To better understand the biological functions of GAGs and particularly of CS-E (4,6-disulfated) at the molecular level, structurally well-defined oligosaccharides are necessary. Chemically synthesised biotinylated conjugates are useful to study the interactions with proteins at the intra- and extracellular levels. Herein, FTIR spectroscopy was used to characterise nine chondroitin oligosaccharides, including biotinylated or reducing CS-E di-, tetra- and hexasaccharides as well as their non-sulfated analogs. Spectral features characteristic of the vibrational modes of oligosaccharides (1640, 1626, 1565, 1418, 1375, and 1160 cm−1), CS-E (1280–1200, 1134, 1065, 1034, 1000, 927, and 866–860, 815 cm−1), and biotin (1681, 1460, 1425, and 792 cm−1) were identified. FTIR spectroscopy was sensitive enough to reveal structural microheterogeneity, allowing distinguishing C-4 from C-6 sulfated isoforms. CS-E- and biotin-specific signatures were obtained via difference spectra. PCA plots revealed three distinct groups: biotinylated oligosaccharides, CS-E biotinylated oligosaccharides and CS-E reducing oligosaccharides. Furthermore, the first component clearly distinguished sulfated from non-sulfated forms, while component two tended to discriminate according to the chain length, exclusively for non-sulfated oligosaccharides. Identifying the spectral signatures of these oligosaccharides is an important step for future research on the monitoring of the internalisation of oligosaccharide- and cell-penetrating peptide-bound forms in drug-delivery studies
Elaboration of the magnetically frustrated GeFe2O4 spinel thin films by pulsed laser deposition
No full textInternational audienc
On the first hitting time of a high-dimensional orthant
No full textInternational audienceWe consider a collection of independent standard Brownian particles (or random walks), starting from a configuration where at least one particle is negative, and study the first time they all become positive. This is clearly equivalent to studying the first hitting time of the positive orthant or the first exit time from the complement of the positive orthant. While it turns out to be possible to compute the distribution of these hitting times for one and two particles, the distribution (and even its tail asymptotics) is not known in closed form for three or more particles. In this paper we study the tail asymptotics of the distribution as the number of particles tends to infinity. Our main techniques come from spectral geometry: we prove new asymptotic estimates for the principal eigenvalue of the complement of a high-dimensional orthant, which we believe are of independent interest
On the origin of mixed inhomogeneous phase in vortical gluon plasma
No full textInternational audienceRecently, lattice simulations of SU(3) Yang-Mills theory revealed that rotating hot gluon matter in thermal equilibrium possesses a novel inhomogeneous phase consisting of the deconfinement phase located in the center region, which is spatially separated from the confinement phase in the periphery. This inhomogeneous two-phase structure is also expected to be produced by vorticity in quark-gluon plasma formed in non-central relativistic heavy-ion collisions. We show that its vortical properties are determined by two types of couplings of the angular velocity to the gluon fields: a linear coupling to the mechanical angular momentum of gluons and a quadratic ``magnetovortical'' coupling to a chromomagnetic component. We demonstrate numerically that the distinctive inhomogeneous structure of the vortical (quark-)gluon plasma is determined by the latter, while the former plays only a subleading role. We argue that the anisotropy of the gluonic action in the curved co-rotating background can quantitatively explain the remarkable property that the spatial structure of this inhomogeneous phase disobeys the picture based on a straightforward implementation of the Tolman-Ehrenfest law. We also support our findings with Monte Carlo simulations of Yang-Mills plasma at the real-valued angular frequency, which take into account only the magnetic part of the action
Centre Val-de Loire, Indre-et-Loire, Amboise, 3 rue Rouget de Lisle. Amboise, oppidum des Châtelliers : du sanctuaire gaulois au sanctuaire antique (100 av. – 70 ap. J.-C.). Rapport de fouille archéologique.
No full textA fast radio burst from the first 3 billion years of the Universe
No full textInternational audienceFast radio bursts (FRBs) are enigmatic millisecond-duration signals which encode otherwise unattainable information on the plasma which permeates our Universe, providing insights into magnetic fields and gas distributions. Here we report the discovery of FRB 20240304B originating at redshift 2.148 +/- 0.001 corresponding to just 3 billion years after the Big Bang. FRB 2024030 was detected with the MeerKAT radio telescope and localized to a low-mass, clumpy, star forming galaxy using the James Webb Space Telescope. This discovery doubles the redshift reach of localized FRBs and probes ionized baryons across ~80% of cosmic history. Its sightline, intersecting the Virgo Cluster and a foreground group, reveals magnetic field complexity over many gigaparsec scales. Our observations establish FRB activity during the peak of cosmic star formation and demonstrate that FRBs can probe galaxy formation during the most active era in cosmic time