The assessment of the carbonaceous component in black crusts damaging the stone surfaces of historical monuments (from Trevi fountain Roma to square San Marco Venice)

The issue of conservation of the monumental heritage is mainly related to atmospheric pollution that causes the degradation of stone surfaces. Black crusts can be formed as a result of different chemical and physical reactions between the stone surface and environmental factors (such as gaseous pollutants and aerosol particulate matter, PM). These black layers present on the stone monuments reflect the composition of the aerosol particulate matter to which the surfaces are exposed. In particular elemental carbon (EC, also known as black carbon, typically emitted by combustion processes) is the PM component responsible for the characteristic black color of the crusts where it is embedded together with calcium sulphate due to the conversion of calcium carbonate, the main constituent of the stone. Organic carbon (OC) represents the other carbonaceous component of PM and it is present in the black crusts, too. It is of both primary or secondary origin and is linked to numerous sources (traffic, heating plants, biomass burning, etc.). A deep knowledge of the crust composition in terms of OC and EC optical properties is mandatory in order to get information on the sources responsible for the surface darkening. OC/EC in PM samples are generally quantified by a reference method (TOT, Thermal Optical Transmittance) not suitable for the analysis of these components in the crusts. A new approach for OC/EC quantification based on a thermal protocol and including CHN and TGA analyses, has been set-up. The method validation has been performed analyzing suitable reference standard samples prepared by mixing different chemical species in order to simulate the composition of the black crusts present on the monument surfaces. Real samples of black crusts coming from historical monuments placed in Rome, Milan and Venice have been analyzed

Effects of different sources of air pollution on the carbonate stone surface of relevant European monuments

This contribution focuses on spectrometric analyses carried out on black crust samples, collected from buildings and churches belonging to the European built Heritage, i.e., the Corner Palace in Venice (Italy), the Cathedral of St. Rombouts in Mechelen (Belgium), the Church of St. Eustache in Paris (France) and the Tower of London (United Kingdom). Such monuments, all built in carbonate stones, were selected for their historic and artistic relevance, as well as for their location in different urban contexts (exposed to intense vehicular traffic or pedestrian areas). For a complete characterization of the black crusts, an approach integrating complementary techniques was used, including optical (OM) and scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM-EDS), Fourier transform infrared spectroscopy (FT-IR) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The complete characterization of the damage layers provided information on their chemical composition, the state of conservation of the underlying substrates and the interactions between crusts and stones. In particular, the geochemical study in terms of trace elements revealed that all crusts are enriched in heavy metals (As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Sn, Ti, V, and Zn) compared to substrates. The different concentrations of such elements in all analyzed crust samples can be ascribed to several factors, such as: height of sampling, morphology of the sampled surfaces (vertical or horizontal), exposure to atmospheric agents, exposure to direct (road or boat traffic) or indirect (industries) sources of pollution, accumulation time of pollutants on the surfaces, wash out and particulate air pollution. Specifically, the crusts collected at lower heights (some samples of the Corner Palace, Cathedral of St. Rombouts and Tower of London) resulted to be mainly influenced by mobile sources of pollution (vehicular or boat traffic), while samples taken at higher heights (Church of St. Eustache and some samples of the Corner Palace) are generally mostly affected by stationary combustion sources. In some cases, the detailed analysis of multilayered crusts (Palazzo Corner) contributed to recognize the variation of combustion sources responsible for the deterioration of surfaces over time. In addition, the possibility of analyzing altered portions of the substrate (Tower of London) permitted to observe that some elements (Zn, Cu and Ni) show concentrations similar and, sometimes, higher than the overlying crusts. This result can be explained by the geochemical mobility of such elements (at specific environmental conditions), which accelerate the process of sulfating, rapidly creating new layers of crust In conclusion, the study of black crusts and altered substrates in terms of trace elements may provide information useful to understand the influence of the pollutants in the genesis of such degradation forms

The assessment of the carbonaceous component in black crusts damaging the stone surfaces of historical monuments.

The issue of conservation of the monumental heritage is mainly related to atmospheric pollution that causes the degradation of stone surfaces. Black crusts can be formed as a result of different chemical and physical reactions between the stone surface and environmental factors (such as gaseous pollutants and aerosol particulate matter, PM). These black layers present on the stone monuments reflect the composition of the aerosol particulate matter to which the surfaces are exposed. In particular elemental carbon (EC, also known as black carbon, typically emitted by combustion processes) is the PM component responsible for the characteristic black color of the crusts where it is embedded together with calcium sulphate due to the conversion of calcium carbonate, the main constituent of the stone. Organic carbon (OC) represents the other carbonaceous component of PM and it is present in the black crusts, too. It is of both primary or secondary origin and is linked to numerous sources (traffic, heating plants, biomass burning, etc.). A deep knowledge of the crust composition in terms of OC and EC optical properties is mandatory in order to get information on the sources responsible for the surface darkening. OC/EC in PM samples are generally quantified by a reference method (TOT, Thermal Optical Transmittance) not suitable for the analysis of these components in the crusts. A new approach for OC/EC quantification based on a thermal protocol and including CHN and TGA analyses, has been here proposed. The method validation has been performed analyzing suitable reference standard samples prepared by mixing different chemical species in order to simulate the composition of the black crusts present on the monument surfaces. In addition the characterization of OC optical properties with UV-visible spectrometry has been performed, to understand the role of light absorbing carbon (i.e. brown carbon) on surface stone darkening. The chemical composition of OC was further investigated with Fourier Transform infrared spectrometry (FT-IR) to identify the contribution of the different organic functional groups to the ageing/browning of stone surfaces. This research aims to get a new simple method for the evaluation of the carbonaceous component of the black crusts which are formed on carbonate stone surfaces. The protocol has been applied to some real samples of black crusts of different provenance

Mineralogical, petrographic and chemical analyses for the study of the canvas "Cristo alla Colonna" from Cosenza, Italy : a case study

A multi-technique study on materials used for the painting "Cristo alla Colonna" by Luigi Bria (private collection, Cosenza, Italy) was carried out for the first time during the restoration plan. Pigments, binder media and raw materials used for the application of ground and priming layers were studied using optical (OM) and electronic microscopy equipped with energy dispersive spectroscopy qualitative microanalysis (SEM-EDS), infrared spectroscopy (FTIR) and gas chromatography coupled with mass spectrometry (GC/MS). The goal of this study was to characterize this canvas and to set up a scientific aid and guide for its restoration, taking into account the, severe damage not exclusively due to natural decay processes. Our data can provide information about historical and stylistic background as well as advises for correct planning of the cleaning procedures. Riassunto - II dipinto su tela "Cristo alla Colonna", opera di Luigi Bria (collezione privata, Cosenza, Italia), \ue8 stato sottoposto, durante le fasi di restauro, per la prima volta ad indagine strumentale tramite varie tecniche analitiche. I pigmenti, i leganti ed altri materiali utilizzati per la sua realizzazione sono stati analizzati tramite microscopia ottica (OM), microscopia elettronica e microanalisi tramite spettrometria a dispersione di energia (SEM-EDS), spettroscopia infrarossa (FTIR) e gascromatografia accoppiata spettrometria di massa (CG/MS). Lo scopo del lavoro \ue8 stato quello di offrire una caratterizzazione dell'opera pittorica, nonch\ue9 fornire un supporto scientifico ad un un corretto intervento di restauro su un'opera fortemente degradata. I risultati hanno permesso di fornire informazioni di natura storico-artistico nonch\ue9 informazioni utili ad un corretto intervento di pulitura della tela oggetto di questo studio

Altered TMPRSS2 usage by SARS-CoV-2 Omicron impacts infectivity and fusogenicity

The SARS-CoV-2 Omicron BA.1 variant emerged in 20211 and has multiple mutations in its spike protein2. Here we show that the spike protein of Omicron has a higher affinity for ACE2 compared with Delta, and a marked change in its antigenicity increases Omicron’s evasion of therapeutic monoclonal and vaccine-elicited polyclonal neutralizing antibodies after two doses. mRNA vaccination as a third vaccine dose rescues and broadens neutralization. Importantly, the antiviral drugs remdesivir and molnupiravir retain efficacy against Omicron BA.1. Replication was similar for Omicron and Delta virus isolates in human nasal epithelial cultures. However, in lung cells and gut cells, Omicron demonstrated lower replication. Omicron spike protein was less efficiently cleaved compared with Delta. The differences in replication were mapped to the entry efficiency of the virus on the basis of spike-pseudotyped virus assays. The defect in entry of Omicron pseudotyped virus to specific cell types effectively correlated with higher cellular RNA expression of TMPRSS2, and deletion of TMPRSS2 affected Delta entry to a greater extent than Omicron. Furthermore, drug inhibitors targeting specific entry pathways3 demonstrated that the Omicron spike inefficiently uses the cellular protease TMPRSS2, which promotes cell entry through plasma membrane fusion, with greater dependency on cell entry through the endocytic pathway. Consistent with suboptimal S1/S2 cleavage and inability to use TMPRSS2, syncytium formation by the Omicron spike was substantially impaired compared with the Delta spike. The less efficient spike cleavage of Omicron at S1/S2 is associated with a shift in cellular tropism away from TMPRSS2-expressing cells, with implications for altered pathogenesis

Consolidating Properties Of Regalrez 1126 And Paraloid B72 Applied To Wood

This study is aimed at an assessment of the properties oftwopolymeric products applied toNorwayspruce (Picea abies) and White poplar (Populus alba)woodspecies. It contributes to ongoing research experiments on the consolidating properties of two synthetic resins and their potential synergic action on wood, resulting from their different interaction with the substrate: Paraloid B72 and Regalrez 1126. Experiments were carried out on a series of samples of the two wood varieties. The consolidants were applied alone and one after the other, with one coat of Regalrez and then one of Paraloid. Porosity and variations in pore size distribution were ascertained by mercury intrusion porosimetry (MIP). Colorimetric and IR spectroscopic measurements were also taken before and after aging by solar radiation and freeze/thaw cycles, to verify the possible slowing of photodegradation of the treated wood and the consolidating resistance. Results confirm that both products penetrate the wood with a different behaviour. After double treatment with Regalrez + Paraloid, a significant advantage was observed in terms of mechanical resistance and pore size distribution, although no advantages as regards resistance to photo-oxidizing processes or colour changes were observed

Diagnostic investigation for the study of the fresco titled “Madonna con il bambino”, in Cosenza, southern Italy : a case study

This study had been focused on the diagnostic analysis of the fresco "Madonna con il bambino" dated back to the late nineteenth century and located in the cave hosting the sanctuary of \u201cSan Michele Arcangelo\u201d in San Donato Ninea (Cosenza), Calabria, southern Italy. A multi-technique investigation on constituting materials was carried out before the restoration procedures [1-2] in 2011. Raw materials, execution techniques and possible previous restorations evidences have been identified [3]. Pigments and raw materials used for the application of the ground and the painting layers were studied using optical investigations (optical and stereo microscopy), electronic microscopy, equipped with energy dispersive spectroscopy qualitative microanalysis (SEM-EDS) and infrared spectroscopy (FT-IR) [4]. Furthermore, the characterization of historical and stylistic background of these paintings, and the evaluation of the decay phenomena affecting them, provided a scientific aid and guide to identify the most suitable and durable restoration process for the mural paint. The collected data were used for the choice of cleaning and consolidation procedures of the whole artwork, demonstrating the importance of a preliminary diagnostic study before a restoration

A new tentative approach for a possible correlation between Cultural Heritage, Pollution and Neuroendocrine Tumours

The result of interaction between atmospheric pollution and carbonate stone materials are the formation of black crust, a superficial layer that assumes a grey to black color. An innovative application of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) as a methodological approach for the chemical characterization of black crust on stone monuments was proposed. This approach is extremely advantageous in geochemical characterization, both to determine a great number of trace elements and to carry out precise and sensitive analyses in a relatively short time. It also provides information about the extent of pollution in environments where black crusts were formed, and specifically, reveals the presence of different heavy metals. Recently some papers reported a possible relation between Cadmium and Arsenic (two heavy metals) in induce a neuroendocrine differentiation and proliferation of breast and urothelial normal cells. A site-by-site analysis is revealed that, for some neuroendocrine tumours, the incidence rate increased more than others. This last aspect probably could be related also to different pollution condition how it was reported for others not-neuroendocrine tumours. Different chemicals agents are characterized by endocrine-disrupting properties; even some metals were shown to have endocrine-disrupting characteristics. The idea is to quantify the heavy metals present in black crusts developing on building stones of several polluted urban area and to define the amount of the same metals in histological tissues of patients affected by neuroendocrine tumours. The aim is to highlight a correlation between contamination of heavy metals in stones materials and human health, in particular regarding neuroendocrine tumors, understanding the role played by each sources of pollution, both natural and anthropogenic in the carcinogenesis of these tumors

Studio preliminare dei parametri termoigrometrici e delle loro variazioni all’interno della chiesa di S. Adriano in San Demetrio Corone (CS).

Gli obiettivi specifici di questa analisi microclimatica sono stati quelli di determinare gli andamenti di temperatura e umidità relativa all’interno della chiese di S. Adriano. Le differenze dei parametri misurati nel corso del tempo dovrebbero consentire successivamente di misurare le variazione tra l’ambiente e i manufatti, considerando che questi gradienti sono la principale causa di degrado delle opere d’arte, con conseguente formazione di flussi di calore e di vapore tra manufatto e ambiente esterno. Le modalità operative, in genere, consistono nell’effettuare campagne di misura significative per ogni stagione, tenendo conto che i dati vanno poi messi in correlazione ai periodi di rilevamento e, nelle 24h, in relazione all’ora in cui si effettua la misura. In questo studio si è preso in considerazione il periodo invernale, con rilevazioni che iniziano nel mese di novembre e che si concludono nel mese gennaio. Il range temporale qui riportato è di circa trenta giorni, considerando che i dati saranno poi integrati con le misure ancora in fieri nei siti in esame. Dai dati rilevati è stato possibile seguire gli andamenti dei parametri di temperatura e umidità relativa sia nell’arco delle 24h (come misure puntuali e come medie delle misure su tutto il periodo in esame) che in tutto il periodo di rilevazione, con le medie calcolate giorno per giorno. In base all’elaborazione di queste misure, è stato possibile elaborare dei tracciati su sezione orizzontale delle chiese che visualizzano l’andamento dei parametri in esame