Search

Le patrimoine culturel recouvre une réalité complexe. Il capte l’ensemble des problématiques de son époque. Il est le lieu où ne cessent de s’articuler des enjeux normatifs, sociaux, politiques, épistémologiques, où se reconfigurent en permanence les rapports entre passé, présent et futur et où les échelles varient, du local au global. L’ère numérique, avec les transformations qu’elle induit dans les processus de patrimonialisation comme dans l’étude des patrimoines, accroît cette complexité tout en appelant de nouveaux regards critiques. Telle est la perspective du présent ouvrage, qui déplie et déploie deux grandes thématiques. Il aborde d’abord les historicités, les spatialités et les reconfigurations temporelles du patrimoine, puis sa production sociale et enfin les médiations, appropriations et ressentis auxquels il donne lieu. Il traite ensuite de l’articulation entre matérialité, immatérialité et dématérialisation, en étudiant cette dernière et ses effets, l’évolution des connaissances sur la matérialité des œuvres, les usages du numérique pour l’accès au patrimoine et sa médiation. Nourri d’un travail collaboratif d’ampleur, il met en lumière les nouvelles pollinisations entre le monde académique et les institutions culturelles patrimoniales et l’accroissement qualitatif qu’elles constituent. Il montre également que l’interdisciplinarité, si elle est conçue comme un processus de co-traduction et de co-construction, constitue un formidable levier pour l’avenir de la recherche sur les patrimoines.

Au XVe siècle, l’un des éléments les plus marquants de la création sculpturale en Toscane, puis en Italie au début de la Renaissance, est le renouveau de l’usage de la terre cuite et du stuc. Depuis le début des années 1980, ce thème est devenu un véritable sujet d’étude pour les historiens d’art italiens, anglais, allemands et français. Ces nouvelles pratiques dans le domaine de la sculpture sont probablement liées à un nouvel intérêt pour le travail de modelage préalable à la création d’œuv...

International audience; Gypsum-based plasters or stuccoes, in spite of their importance and diffusion, received little attention in cultural heritage materials studies. This work introduces a new, non-destructive methodology, using micro-tomography to measure the water/plaster ratio and the morphology of the hemihydrate powder used to make plasters on < 1 mm3 samples. This methodology give insight in both the raw material (and ultimately provenance) and the technique used to make plaster. The methodology was tested first on mock-up samples of known composition, then in a case study on 13 low-relief cast plaster sculptures from 15th century Florentine artists. Preliminary conclusions on this limited corpus show relative uniformity across most reliefs in terms of raw materials and techniques. The casts of one model (Nativity, attributed to Donatello and B. Bellano) were made with a different raw material, in line with prior geochemical analyses; these results support the previous attribution to a North Italian rather than Florentine origin. The casts of a second model (Virgin and Child, type of Saint Petersburg, attributed to Antonio Rossellino) were prepared with a different technique. This surprising result was not expected from Art History or previous studies.

Poly(3,4-ethylenedioxythiophene/permethylated β-cyclodextrin) polypseudorotaxane (PEDOT⋅TMβCD) (P1) was synthesized by the chemical oxidation of 3,4-ethylenedioxythiophene (EDOT) as an inclusion complex with 2,3,6-tri-O-methyl β-cyclodextrin (TMβCD) (EDOT·TMβCD) with a five-fold excess of iron (III) chloride oxidant over the stoichiometric amount in water. The obtained P1 was converted to its P2 polyrotaxane by the end capping of the PEDOT backbones with bulky triphenylmethane to avoid the dethreading of TMβCD. The chemical structures of P1 and P2 were proved by FT-IR and 1H NMR spectroscopy. The coverage ratios of the P1 and P2 chains were found to be 43.7 ± 5.2% and 27.1 ± 2.8%, respectively. Rotaxane formation results in improvements of the solubility in common organic solvents, as well better film forming ability combined with a high transparency. The UV–Vis absorption of P2 in C6H5Cl/CHCl3 (1/1 v/v) exhibits a hypsochromic shift of 4 nm compared with P1. Atomic force microscopy, AFM, indicated that the P1 film is more uniformly distributed over the substrate area compared to that of the P2, although both surfaces have the roughness parameter values close to 2.90 nm. The newly synthesized compounds were then applied as dopant/additive-free hole transport materials in perovskite solar cells. P1 exhibited a photovoltaic performance of 5.54% under 1 sun illumination, whereas P2 showed a lower efficiency (3.8%) attributed to its lower photocurrent density. These performances are comparable to those obtained for control devices using as hole transporter spiro-OMeTAD (6.27% as dopant/additive-free hole transport material, 14.41% in LiTFSI and tert-butylpyrridine doped system).

In hard X-ray applications that require high detection efficiency and short response times, such as synchrotron radiation-based Mössbauer absorption spectroscopy and time-resolved fluorescence or photon beam position monitoring, III–V-compound semiconductors, and dedicated alloys offer some advantages over the Si-based technologies traditionally used in solid-state photodetectors. Amongst them, gallium arsenide (GaAs) is one of the most valuable materials thanks to its unique characteristics. At the same time, implementing charge-multiplication mechanisms within the sensor may become of critical importance in cases where the photogenerated signal needs an intrinsic amplification before being acquired by the front-end electronics, such as in the case of a very weak photon flux or when single-photon detection is required. Some GaAs-based avalanche photodiodes (APDs) were grown by a molecular beam epitaxy to fulfill these needs; by means of band gap engineering, we realised devices with separate absorption and multiplication region(s) (SAM), the latter featuring a so-called staircase structure to reduce the multiplication noise. This work reports on the experimental characterisations of gain, noise, and charge collection efficiencies of three series of GaAs APDs featuring different thicknesses of the absorption regions. These devices have been developed to investigate the role of such thicknesses and the presence of traps or defects at the metal–semiconductor interfaces responsible for charge loss, in order to lay the groundwork for the future development of very thick GaAs devices (thicker than 100 μm) for hard X-rays. Several measurements were carried out on such devices with both lasers and synchrotron light sources, inducing photon absorption with X-ray microbeams at variable and controlled depths. In this way, we verified both the role of the thickness of the absorption region in the collection efficiency and the possibility of using the APDs without reaching the punch-through voltage, thus preventing the noise induced by charge multiplication in the absorption region. These devices, with thicknesses suitable for soft X-ray detection, have also shown good characteristics in terms of internal amplification and reduction of multiplication noise, in line with numerical simulations.

Male infertility is a worldwide clinical issue that increases the number of couples resorting to assisted reproductive technologies (ARTs) to achieve pregnancy. Photobiomodulation therapy (PBMT) is a promising technique that can biostimulate cells and tissues and it is currently successfully employed to enhance the sperm motility in vitro. Nevertheless, its use has been so far restricted to the research field. In the present work, we exploited two PBMT protocols at an 800 nm wavelength on sperm derived from infertile individuals, detecting an increase in sperm motility 1 hour after irradiation. Moreover, in order to add new information about the molecular effect of PBMT, the content of some light elements was evaluated using high resolution X-ray fluorescence imaging. Interestingly, an increase in Na content was detected in the irradiated samples, possibly suggesting a role of this element in sperm motility; indeed, a low Na content was previously correlated with a poor sperm quality, low semen volume, and modest fertilization rate. Amplifying the knowledge of PBMT in the ART field will expedite the translational potentiality of the PBMT use in clinical settings.