La Victoire d’Arles : une dorure à la feuille exemplaire et complexe

Le présent texte résume les résultats de la partie de l’étude de l’applique de la Victoire d’Arles consacrée à la dorure à la feuille qui la décore dans son ensemble. Cette étude vient en complément des premiers travaux exposés dans l’article du catalogue César : le Rhône pour mémoire, 2 ans de fouille dans le fleuve à Arles consacré à l’étude technique de la Victoire, en particulier des analyses faites au CICRP de Marseille en 2009 par Nicolas Bouillon. La dorure a fait au C2RMF l’objet de séries d’examens et de mesures par microscopie optique, fluorescence X portable et analyses PIXE et RBS à l’accélérateur de particules AGLAE. Deux fragments ont été examinés et analysés en microscopie optique à 2 et 3 dimensions, en diffraction de rayons X et au microscope à balayage analytique. Un microprélèvement a également été analysé en chromatographie en phase gazeuse couplée à la spectrométrie de masse. Les résultats permettent de mesurer les épaisseurs des feuilles d’or, de mettre en évidence les recouvrements dus à des redorures et de caractériser la famille chimique de l’adhésif antique employé. Une discussion est engagée concernant la nature des bandes horizontales de dorure bien préservée sur le chiton du personnage.The present article summarises the results of the investigation on the gilding, which covers the Victory of Arles. This study complements the earlier investigation conducted by Nicolas Bouillon at Marseille’s CICRP in 2009 and published in Long, Picard 2009. In the C2RMF laboratory, the gilding was submitted to a series of tests and measurements by optical microscopy, portable X-ray fluorescence and PIXE and RBS analyses on the AGLAE particle accelerator. Two fragments were observed and analysed by two-dimensional and three-dimensional optical microscopy, X-ray diffraction, analytical scanning electron microscopy and by gas chromatography coupled with mass spectrometry of a micro-sample. The results reveal the thickness of the gold leaf, show evidence for areas with gold overlapping due to re-gilding and allow also the characterization of the chemical class of the adhesive used in antiquity for the gold leaf application. A discussion is developed about the nature of the well-preserved gilded bands on the figure’s chiton

Tenogenically induced allogeneic mesenchymal stem cells for the treatment of proximal suspensory ligament desmitis in a horse

Suspensory ligament injuries are a common injury in sport horses, especially in competing dressage horses. Because of the poor healing of chronic recalcitrant tendon injuries, this represents a major problem in the rehabilitation of sport horses and often compromises the return to the initial performance level. Stem cells are considered as a novel treatment for different pathologies in horses and humans. Autologous mesenchymal stem cells (MSCs) are well known for their use in the treatment of tendinopathies; however, recent studies report a safe use of allogeneic MSCs for different orthopedic applications in horses. Moreover, it has been reported that pre-differentiation of MSCs prior to injection might result in improved clinical outcomes. For all these reasons, the present case report describes the use of allogeneic tenogenically induced peripheral blood-derived MSCs for the treatment of a proximal suspensory ligament injury. During conservative management for 4 months, the horse demonstrated no improvement of a right front lameness with a Grade 2/5 on the American Association of Equine Practitioners (AAEP) scale and a clear hypo-echoic area detectable in 30% of the cross sectional area. From 4 weeks after treatment, the lameness reduced to an AAEP Grade 1/5 and a clear filling of the lesion could be noticed on ultrasound. At 12 weeks (T-4) after the first injection, a second intra-lesional injection with allogeneic tenogenically induced MSCs and platelet rich plasma was given and at 4 weeks after the second injection (T-5), the horse trotted sound under all circumstances with a close to total fiber alignment. The horse went back to previous performance level at 32 weeks after the first regenerative therapy and is currently still doing so (i.e., 20 weeks later or 1 year after the first stem cell treatment). In conclusion, the present case report demonstrated a positive evolution of proximal suspensory ligament desmitis after treatment with allogeneic tenogenically induced MSCs

Exploiting Chordality in Optimization Algorithms for Model Predictive Control

In this chapter we show that chordal structure can be used to devise efficient optimization methods for many common model predictive control problems. The chordal structure is used both for computing search directions efficiently as well as for distributing all the other computations in an interior-point method for solving the problem. The chordal structure can stem both from the sequential nature of the problem as well as from distributed formulations of the problem related to scenario trees or other formulations. The framework enables efficient parallel computations.Comment: arXiv admin note: text overlap with arXiv:1502.0638

Étude de la marqueterie d’un secrétaire à gradin du xviiie siècle

Le secrétaire à gradin (inv. V4081) conservé au musée du Louvre a fait l’objet d’une restauration en 2013 dans les ateliers du Centre de recherche et de restauration des musées de France (C2RMF), au pavillon de Flore. L’intervention s’est accompagnée d’une importante étude matérielle de la partie polychromée de la marqueterie. Les procédés de mise en œuvre de la couche picturale et de la couche de corne qui la protège ont nécessité d’adapter la méthodologie par le couplage de multiples techniques d’examens et d’analyses. Le recoupement de l’ensemble des données a permis de caractériser finement les matériaux utilisés pour deux interventions distinctes de polychromies et de mieux cerner les dates de leur mise en œuvre.The Louvre’s drop-front secretary desk with drawers (inv. V4081) was restored in 2013 in the workshops of the Centre de Recherche et de Restauration des Musées de France (C2RMF), in the Pavillon de Flore. The restoration went hand in hand with a detailed material study of the polychromed part of the marquetry. The manner of applying the layer of pigment and the veneer of horn that protected it required the methodology to be adapted through the interaction of multiple tests and analysis techniques. By cross-referencing all the data obtained, the materials used for the two separate polychromy procedures were distinguished and dated more precisely

A comprehensive study of three different portable XRF scanners to assess the soil geochemistry of an extensive sample dataset

The assessment of soil elemental concentrations nowadays mainly occurs through conventional laboratory analyses. However, proximal soil sensing (PSS) techniques such as X-ray fluorescence (XRF) spectrometry are proving to reduce analysis time and costs, and thus offer a worthy alternative to laboratory analyses. Moreover, XRF scanners are non-destructive and can be directly employed in the field. Although the use of XRF for soil elemental analysis is becoming widely accepted, most previous studies were limited to one scanner, a few samples, a few elements, or a non-diverse sample database. Here, an extensive and diverse soil database was used to compare the performance of three different XRF scanners with results obtained through conventional laboratory analyses. Scanners were used in benchtop mode with built-in soil calibrations to measure the concentrations of 15 elements. Although in many samples Cu, S, P, and Mg concentrations were up to 6, 12, 13, and 5 times overestimated by XRF, and empirical recalibration is recommended, all scanners produced acceptable results, even for lighter elements. Unexpectedly, XRF performance did not seem to depend on soil characteristics such as CaCO3 content. While performances will be worse when expanding to the field, our results show that XRF can easily be applied by non-experts to measure soil elemental concentrations reliably in widely different environments

Equine allogeneic chondrogenic induced mesenchymal stem cells are an effective treatment for degenerative joint disease in horses

Degenerative joint disease is one of the main causes of equine early retirement from pleasure riding or a performance career. The disease is initially triggered by an abnormal loading of normal cartilage or a normal loading of abnormal cartilage. This primary insult is accompanied with joint inflammation, which leads to further progressive degeneration of the articular cartilage and changes in the surrounding tissues. Therefore, in search for an effective treatment, 75 adult horses with early signs of degenerative fetlock joint disease were enrolled in a randomized, multicenter, double-blinded, and placebo-controlled study. Fifty animals were injected intra-articularly with the investigational veterinary product (IVP) consisting of allogeneic chondrogenic induced mesenchymal stem cells (ciMSCs) with equine allogeneic plasma, and 25 horses were injected with 0.9% NaCl (saline) control product. From week 3 to 18 after treatment, lameness scores (P<0.001), flexion test responses (P<0.034), and joint effusion scores (P<0.001) were remarkably superior in IVP-treated horses. Besides nasal discharge in both treatment groups, no adverse events were observed during the entire study period. On long-term follow-up (1 year), significantly more investigational product-treated horses were working at training level or were returned to their previous level of work (P<0.001)