Artificial reproduction of natural and artistic patinas on bronze mock-ups to be used as sacrificial substrates for the validation of new conservation materials

Modern, historical and artistic bronze sculptures frequently present a matt and colored surface rather than a pure metallic appearance. Color changes can be related to the occurrence of alteration phenomena or to an intentional patination designed by the artists. In the first case, bronze artworks, especially those exposed outdoor, naturally react with atmospheric pollutants, such as SOx, NOx, O3, airborne particulate matter (PM), to form green sulfate species (Chiavari et al., 2007), sometimes appreciated for the old-like appearance they provide to the object. On the contrary, artistic patinas are intentionally applied to the works of art to obtain special chromatic effects and emphasize textured surfaces with light and shade effects. Although recipes used by artists to artificially patinate modern sculptures are commonly kept secret, it is known that they are based on the use of reagents like “liver of sulfur” (K2S), copper nitrates or iron nitrates (Bongiorno et al., 2012; Crippa et al., 2019). In both cases, the surface reactivity significantly changes (Kosec et al., 2021), and tailored conservation practices are required to protect this type of materials from disfiguring degradation processes. In this work, several existing methods to artificially patinate bronze substrates were tested and critically compared with the aim of developing an easy and comprehensive standard procedure to obtain bronze patinas with different colors, structure and minero-chemical composition, representative of both natural and artistic aged surfaces. Copper and iron nitrates, copper sulfates and potassium sulfide were selected as patinating agents for both immersion and hot-brushing treatments. The morphological, chemical and mineralogical features of the patinas were studied by a multianalytical approach, including optical microscopy (OM), field emission scanning electron microscopy coupled with energy dispersion spectroscopy (FE-SEM-EDS), Fourier transform infrared spectroscopy in attenuated total reflection mode (ATR-FTIR) and x-ray diffraction (XRD). Results pointed out that by properly varying the patination procedure a set of artificial patinas, representative of different typologies of bronze artifacts surfaces, are easily obtained. Therefore, these patinas can be used as sacrificial substrates to reliably validate new conservation materials. The national PRIN 2017249YEF project and the GREENART project (Horizon Europe research and innovation program under GA no. 101060941) are gratefully acknowledged for financial support. Bongiorno V., Campodonico S., Caffara R., Piccardo P. & Carnasciali M.M. (2012) - Micro-Raman spectroscopy for thecharacterization of artistic patinas producedon copper-based alloys. J. Raman Spectrosc., 43, 1617-1622. https:// doi.org/10.1002/jrs.4167. Chiavari C., Rahmouni K., Takenouti H., Joiret S., Vermaut P. & Robbiola L. (2007) - Composition and electrochemical properties of natural patinas of outdoor bronze monuments. Electrochim. Acta, 52(27), 7760-7769. https://doi. org/10.1016/j.electacta.2006.12.053. Crippa M., Bongiorno V., Piccardo P. & Carnasciali M.M. (2019) - A characterisation study on modern bronze sculpture: the artistic patinas of Nado Canuti. Stud. Conserv., 64(1), 16-23. https://doi.org/10.1080/00393630.2018.1492253. Kosec T., Novak Ž., Fabjan E.Š., Škrlep L., Škapin A.S. & Ropret P. (2021) - Corrosion protection of brown and green patinated bronze. Prog. Org. Coat., 161, 106510. https://doi.org/10.1016/j.porgcoat.2021.106510

#ScienzeABC: pills of digital knowledge to tell the Sciences Applied to Cultural Heritage

In recent years, also due to the COVID-19 pandemic, the use of the internet and social networks has significantly increased, both for personal entertainment and for study/ training needs. No topic has been spared by digitization: even the humanities and sciences have had a significant increase on the main search provider since February 2020. These disciplines are often considered diametrically opposed but, above all in the Cultural Heritage field, science and art merge in the creation phase of a work of art as much as in its conservation process. The idea of starting and managing an Instagram profile about sciences applied to cultural heritage (called @scienze.abc) stems from the desire to contribute to reduce the distance between art and science, promoting greater visibility of STEM subjects, with the aim of spreading the knowledge of the Sciences Applied to Cultural Heritage and to introduce the younger audience to the degree course focused of these disciplines. The project fits into the context of digital learning, applying the tools (e.g. posts, reels and stories) provided by the social network platform Instagram. Pills of scientific knowledge, fun facts and advises about Cultural Heritage are proposed combining short and simple captions with impressive images. In particular, the topics selected for the daily posts concern the activities of scientific experts for Cultural Heritage (Conservation Scientist) carried out in the laboratory and in-situ, the tools of the trade, news from national and international scientific community, curiosities from the world of Cultural Heritage and historical-archaeological-artistic places of interest, more or less known. The language chosen is essential and at the same time scientific and informative, using the typical register of the social networks. The targe

Inactivation of the ELIP1 and ELIP2 genes affects Arabidopsis seed germination

P>Light regulates Arabidopsis seed germination through the phyB/PIL5 (PHYTOCHROME INTERACTING FACTOR 3-LIKE 5) transduction pathway, and we have previously shown that the Dof transcription factor DOF AFFECTING GERMINATION1 (DAG1) is a component of this pathway. By means of microarray analysis of dag1 and wild type developing siliques, we identified the EARLY LIGHT-INDUCED PROTEIN1 and 2 (ELIP1 and ELIP2) genes among those deregulated in the loss-of-function dag1 mutant. We analysed seed germination of elip single and double mutants, of elip dag1 double mutants as well as of elip1 elip2 dag1 triple mutant under different environmental conditions. We show that ELIP1 and ELIP2 are involved in opposite ways in the control of this developmental process, in particular under abiotic (light, temperature, salt) stress conditions