Multifunctional and Durable Coatings for Stone Protection Based on Gd-Doped Nanocomposites

The development of nanocomposite materials with multifunctional protective features is an urgent need in many fields. However, few works have studied the durability of these materials. Even though TiO2 nanoparticles have been extensively applied for self-cleaning effect, it displays a weak activity under visible light. Hence, in this study, pure and Gd-doped TiO2 nanoparticles (molar ratios of doping ions/Ti are 0.1 and 1) were synthesised, characterised, and then mixed with polydimethylsiloxane (PDMS), used as a binder, in order to produce a homogenised thin film on a very porous stone substrate. To our knowledge, Gd-doped TiO2/PDMS protective coatings are studied for the first time for application on historic structures. The protective coatings developed in this work are intended to reduce the surface wettability of the stone and protect the historic stones from dye pollution and microorganism colonisation. Moreover, in this study, the durability of the developed nanocomposite was deeply studied to evaluate the stability of the coatings. Results confirmed that samples treated with the lowest concentrations of Gd ions (0.1 mol%) showed acceptable chromatic variations, a good repellent feature, acceptable water vapour permeability, good durability, the highest self-cleaning activity, and good inhibitory behaviour against microbial colonisation

Silver Nanoparticles in the Cultural Heritage Conservation

Our cultural heritage is our invaluable social and environmental resource and concern. Moreover, it is a key global economic driver. However, they are subjected to deterioration process and aging. Particularly, microorganisms are nowadays considered harmful agents of biodeterioration of artistic materials due to the fact that their interactions with the material cause not only an esthetical damage due to their visible growth on the surface, but they may affect the interested materials in different ways and at different degrees via mechanical and biochemical processes leading to the formation of pitting, scaling and, in the worst scenario, to the loss of material by its detachment. To protect our shared tangible cultural heritage from biodeterioration and preserve it for future generations, several methods have been developed. Notably, using nanomaterials, with antimicrobial features, has been considered an interesting and economical method to preserve valuable heritage materials. In this chapter, we will present an overview of the decay mechanisms that participate in the deterioration of tangible artworks, in particular microorganisms’ colonization. Next, current works that have been developed to use silver nanoparticles to protect heritage items from microbial colonization and prevent their deterioration have been detailed

Chemoorganotrophic bacteria isolated from biodeteriorated surfaces in cave and catacombs

The main objective of this work was the comparative analysis of a large number of bacterial strains isolated from biodeteriorated surfaces in three different sites, namely the catacombs of St. Callistus in Rome, Italy, the catacombs dedicated to St. Agatha in Rabat, Malta and the Cave of Bats in Zuheros, Spain. Our results showed that even considering only culturable chemoorganotrophic bacteria the variability is very high, reflecting the great variety of microhabitats present. Hence any strategies to prevent, control or eliminate the biofilm-embedded microbiota from an archeological surface should take into account a number of considerations as stipulated in our study

Chemoorganotrophic bacteria Isolated From Biodeteriorated Surfaces In Cave And Catacombs

The main objective of this work was the comparative analysis of a large number of bacterial strains isolated from biodeteriorated surfaces in three different sites, namely the catacombs of St. Callistus in Rome, Italy, the catacombs dedicated to St. Agatha in Rabat, Malta and the Cave of Bats in Zuheros, Spain. Our results showed that even considering only culturable chemoorganotrophic bacteria the variability is very high, reflecting the great variety of microhabitats present. Hence any strategies to prevent, control or eliminate the biofilm-embedded microbiota from an archeological surface should take into account a number of considerations as stipulated in our study

Suitability of Gadolinium doped TiO2 nanoparticles to protect heritage building materials from biodeterioration

Heritage buildings possess historical values coming from the attractive architecture and important events taking place around the heritage area. However, they are subjected to degradation process and ageing. Particularly, microorganisms are usually related to harmful biodegradation of artistic materials. Water also is an essential factor of deterioration precisely in porous materials. To protect heritage materials, several methods have been developed. Notably, using nanomaterials to preserve valuable heritage surfaces has been considered as an alternative method. In particular, TiO2 nanoparticles (NPs) have been extensively regarded as one of the most interesting materials. Their interesting features make them a good candidate for photocatalytic application. However, the necessity of using only UV light hinders their practical application. For that reason doping with lanthanide ions, precisely, Gadolinium (Gd) could be an effective method to enhance TiO2 NPs photoactivity. In the present study, pure and Gadolinium doped TiO2 NPs were synthesized by sol-gel method. Prepared NPs were dispersed in a binder at different powder/binder ratios: (0.1, 0.2, 0.5 and 1%w/wTiO2). However, before any application on artefacts, the nanomaterials need to be tested for their biocide efficiency and importantly for being harmless to cultural heritage material. X-ray powder diffractometry (XRPD), UV-Visible and Raman spectroscopies, scanning electron microscopy (SEM), and energydispersive X-ray spectroscopy (EDS) were used to characterize the as-prepared nanopowders. A set of experiments has been performed in order to investigate Gd3+-doped TiO2 nanomaterials as effective photocatalysts, for their photokilling activity against selected Gram positive and Gram negative bacteria and for the chromatic changes induced after their application on Lecce stone surfaces by performing colorimetric measurements

Fungal outbreak in the Catacombs of SS. Marcellino and Pietro Rome (Italy): From diagnosis to an emergency treatment

9 páginas.- 5 figuras.- 3 tablas.- referencias.-. The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fmicb. 2022.982933/full#supplementary-material .- This article is part of the Research Topic Microbial Roles in CavesThe present study reports a sudden fungal outbreak that occurred in the corridor near the entrance of the Catacombs of SS. Marcellino and Pietro in Rome (Italy) observed after 1 year of a restoration treatment that interested the walls of the entrance of the Catacombs and some artifacts placed in situ. The colonization was observed on the vault at the entrance and in correspondence with the restored marble pieces displayed on the left side of the corridor. No growth was observed on the right side where similarly treated marble slabs were placed. Samples taken in correspondence with fungal biofilm were analyzed through the combined use of microscopical, cultural, and molecular tools and showed that the vault and the left side of the corridor entrance were colonized by a complex fungal biofilm consisting mainly of Coniophora sp. and other genera, such as Hypomyces, Purpureocillium, Acremonium, Penicillium, and Alternaria, many of which are well known as responsible of biodeterioration of stone surfaces. Regarding the brown-rot basidiomycete Coniophora, it was able to form very large colonies on the substrata with a diameter of up to 57 cm. Although the direct observation under a light microscope evidenced the presence of abundant brown fungal conidia, several attempts to cultivate the microorganism failed, therefore only through DNA sequencing analyses, it was possible to identify and characterize this fungus. There is very little literature on the genus Coniophora which is reported as one of the causes of wet-rot decay of wood in buildings. A connection with calcium-containing materials such as bricks and mortars was demonstrated, but no data were available about the possible role of this species in the biodeterioration of stones. This study features the first finding of a strain related to the basidiomycetous genus of Coniophora in the order Boletales in association with evident phenomena of biodeterioration.This project was supported thanks to the special funds provided by the University of Messina (approved on 21 February 2022 by the Academic Senatus) (Italy), the Spanish Ministry of Science and Innovation, and project PID2020-114978GB-I00 and project CIACCO DTC TE1 - FASE II - PROGETTI RSI8.Peer reviewe

Photo-enhanced Gd-TiO2/PDMS nanocomposites for stone preservation

The protection of stone artifacts from different defacements (chemical, physical and biological agents) is an essential event due to their historical value. Hence, many research groups have focused on developing nanocomposite materials with multifunctional protective features to protect building stones, especially with high porosity and to reduce the high cost of maintenance of these materials. TiO2 nanoparticles have been extensively used for self-cleaning applications, particularly, cleaning and preventing colonization of heritage building material surfaces. However, this semiconductor displays a weak activity under visible light, which can be properly enhanced by doping with Lanthanide ions. In addition, their inert colours make it possible to elaborate transparent thin films. The present research work focused to develop photo enhanced nanocomposite coatings: pure and Gd doped TiO2 nanoparticles with different doping amounts were mixed with Polydimethylsiloxane (PDMS) used as a binder. Moreover, newly prepared coatings were applied on a very porous stone substrate (Lecce stone) in order to investigate the self-cleaning properties and the protecting ability towards the historic stones from dye pollution and micro-organisms colonization. For this purpose, different analyses and tests have been performed on the coated stone specimens such as chromatic measurements, static contact angle measurements, water capillary absorption test, permeability to water vapour, pencil hardness test, scanning electron microscope combined with energy-dispersive X-ray spectroscopy (SEM-EDS), optical microscope analyses, self-cleaning test and biological experiments. In addition, the durability of the coatings was studied to evaluate the stability of the elaborated nanocomposites. Results showed that PDMS mixed with 0.1 mol% Gd-TiO2 materials can be considered as a promising and durable candidate to protect highly porous heritage building surfaces

Global molecular diversity of the halotolerant fungus Hortaea werneckii

A global set of clinical and environmental strains of the halotolerant black yeast-like fungus Hortaea werneckii are analyzed by multilocus sequencing and AFLP, and physiological parameters are determined. Partial translation elongation factor 1-α proves to be suitable for typing because of the presence/absence of introns and also the presence of several SNPs. Local clonal expansion could be established by a combination of molecular methods, while the population from the Mediterranean Sea water also responds differently to combined temperature and salt stress. The species comprises molecular populations, which in part also differ physiologically allowing further diversification, but clinical strains did not deviate significantly from their environmental counterparts

The changing nature of work and skills in the digital age

This report aims to shed light on some of the key drivers which are worth taking into account when assessing the effect of new technologies on the future of work and skills. It combines a synthesis of the most recent and robust scientific evidence available with original JRC research on issues which have been often overlooked by existing studies. In particular, the report provides new insights on the interplay between automation and work organisation, the extent and nature of platform work, and the patterns of occupational changes across EU regions. The first chapter discusses the impact of technology on employment. It overviews the most recent estimates on technology-induced job creation and destruction, and provides new insights on the role of workplace organisation in shaping the effect of new technologies on labour markets. The second chapter discusses how skills needs are shifting towards digital and non-cognitive skills, showing evidence of an increasing shortage of these skills in the EU, which education systems are not fully tackling yet. The third chapter reviews the opportunities and challenges related to the recent upwards trend in new forms of employment in the EU, focusing on the results of the second wave of the COLLEEM survey on platform work in the EU. The final chapter presents results from a new JRC-Eurofound study on the patterns of occupational change in EU regions in the last 15 years which shows that low-wage jobs have increasingly concentrated in peripheral regions while higher-wage jobs are becoming more and more concentrated in capital regions, leading to increasing territorial disparities, both across and within EU Member States.JRC.B.7-Knowledge for Finance, Innovation and Growt