Preparation and Performance of Leather-Finished Plywood.

In order to achieve batch production, we propose a simple and fast method to prepare leather-finished plywood. In this study, ethylene-vinyl acetate was selected as the intermediate layer to prepare EVA/polyurethane (PU) leather composites. ESEM, tensile property test and compressive property test were used to characterize the microstructure and physical-mechanical properties of the composites. The response surface method (RSM) was also used to explore the relationship between hot pressing temperature, hot pressing pressure and hot pressing time. The significance of the factors and the interactions between the two factors were determined by ANOVA, with the most significant effect being that of the temperature. The theoretical optimal hot pressing process conditions were calculated by the regression equation as a temperature of 124.4 °C, a time of 200 s and a pressure of 1.3 MPa. The surface bond strength of the test specimen measured under this condition was 1.89 MPa, it has good finishing properties and the impregnation peel strength and surface bond strength met the requirements of GB/T 15104-2021.

Leonardo's Donna Nuda unveiled.

The painting "Donna Nuda" by Leonardo was acquired by Catherine II (the Great) from the R. Walpole collection, Houghton Hall, England, in 1779 for the Hermitage in St. Petersburg. By exploiting the EVA film technology (ethylene vinyl acetate polymer embedded with strong cation and anion exchangers and with C8 and/or C18 resins) we have explored the surface of the painting in order to ascertain the techniques used in its drawing. Five EVA films were affixed on the body and on the landscape for 60 min. Upon elution from the recovered films, the harvested material was analyzed by gas-chromatography/mass spectrometry as well as by liquid chromatography/mass spectrometry. "Tempera grassa" (consisting of linseed oil admixed with egg yolk) was used in the entire painting. The surface was then protected by a layer of conifer resin. It is hypothesized that access to the layer underneath the protective layer was obtained via micro-cracks on the conifer resin itself. Rosemary oil was used as diluent to slow down the drying process and so to perform the glazing technique, thus obtaining the "aerial perspective" in correspondence of the landscape. To our reckoning, this is the first time in which a Leonardo painting is analyzed in depth but also in which his artistic technique is deciphered via modern techniques for exploring Cultural Heritage. The EVA film technology might be used for ascertaining the authenticity of paintings and uncover frauds. SIGNIFICANCE STATEMENT: Leonardo da Vinci was the most famous Italian polymath of the Renaissance and one of the most important innovators of his time. He was the author of several important artworks such as "La Gioconda", but he also painted the "Donna Nuda" conserved at the Hermitage Museum. Although some attempts permitted the identification of part of the materials used by Leonardo, to date no analytical investigations were able to fully characterize and decipher the recipes. We explored the surface of the "Donna Nuda" painting through a non-invasive approach that uses a functionalized film to adsorb nano-scopic amounts of materials that were then analyzed by mass spectrometry. This method has the potential to revolutionize the approaches used to analyze cultural heritage.

Anton Chekhov and Robert Koch Cheek to Cheek: A Proteomic Study.

Five different letters and post cards as well as the shirt worn by Anton Chekhov on his death bed, stored in the State Literary-Memorial Museum-Reserve A. P. Chekhov Melikhovo (nearby Moscow), have been analyzed by applying EVA (an ethyl vinyl acetate foil studded with crushed strong anion and cation exchangers and with C8 resins) diskettes to these surfaces. Three different eluates (under acidic and basic conditions and with acetonitrile) were analyzed by high resolution mass spectrometry. The environmental microbiota present on samples and the Mycobacterium tuberculosis strain were described by a meta-proteomics approach. Eight identified M. tuberculosis proteins confirmed the presence of the bacterium and the cause of Chekhov's death, in addition to several sequenced peptides belonging to other bacterial species. The human plasma proteins and human keratins, detected on a tiny blood spot on the shirt, demonstrated the power of the combined approach.

Of mice and men: Traces of life in the death registries of the 1630 plague in Milano.

The death registries of the plague epidemic of 1630, stored at the Archivio di Stato of Milano, have been interrogated via the EVA film technology (ethyl vinyl acetate film studded with crushed strong anion and cation exchangers as well as C8 resins). The EVA diskettes have been left in contact with the lower right margins of 11 different pages pertaining to the peak months of the raging disease (June through end of September) for 60-90min and then the captured material, after elution and digestion, analysed by mass spectrometry. The main findings: 17 Yersiniaceae family proteins, 31 different human keratins, 22 unique mouse keratins, about 400 peptides from different bacterial strains, 58 human tissue proteins and 130 additional mouse and rat tissue proteins. In addition, >60 plant proteins (notably potato, corn, rice, carrot and chickpeas), likely representing the meagre meals of the scribes, contaminating the pages, were detected. The significance of these unique findings is amply illustrated in the body of the article. SIGNIFICANCE: Archivists, historians, librarians usually explore the texts of ancient and modern manuscript in order to extract the meaning of the writing and understand the mood, feelings, political, philosophical and/or religious ideas therein expressed by the authors. With the present EVA methodology (the only one, at present, able to access our Cultural Heritage without damaging or contaminating it) we interrogate, instead, the support, be it paper, parchment, wood panel, cloth, canvas and the like, in order to extract invisible data, such as the presence of drugs, medicaments, infectious pathogens, human and environmental contaminants. Metabolites, proteins and peptides thus captured are then analysed via mass spectrometry. The unique data mined by this technology should considerably enlarge the (so far) restricted horizon of the writing exploration and add new insight on the environmental conditions in which such documents were produced as well as, importantly, on the health/pathological conditions of the authors. It is believed that the present technology, as here reported, will become the officially accepted one for exploring the world Cultural Heritage.