Non-Destructive Analytical Investigation of Decorative Wallpapers Samples of the Nineteenth Century before Their Restoration

In this work, decorative wallpapers (19th century) from an historical palace located in Oiartzun (Basque Country, Spain) were analyzed before their restoration. Micro-energy dispersive X-ray fluorescence spectroscopy, Raman spectroscopy, and attenuated total reflectance infrared spectroscopy were used to investigate the elemental and molecular composition of pigments, the presence of binders, and the state of conservation of the paper support. The aim of the investigation was trying to understand the possible degradation pathways and identify the raw materials in order to choose the best restoration protocol according to the original aspect of wallpapers. As stated from both the elemental distribution and the identification of mineral phases by Raman spectroscopy, the most used pigment was lead chromate. It was mixed with other pigments such as ultramarine blue, zinc chromate, hematite, and atacamite among others to obtain different shades and they were applied mixed with an animal glue. Brass, identified thanks to elemental micro-EDXRF maps, was employed as a shiny decorative element. In addition, a partial degradation of cellulose was detected due to its natural ageing, the acidic nature of lignin, and to a phenomenon of humidity of the walls. Probably the deposition of black particulate matter was the cause of the darkening of the painting surfaces.This work has been funded by the DEMORA project (Grant No. PID2020-113391GB-I00), funded by the Spanish Agency for Research (through the Spanish Ministry of Science and Innovation, MICINN, and the European Regional Development Fund, FEDER) I. Costantini thanks their post-doctoral contracts from the University of the Basque Country (UPV/EHU)

Misinterpretation in microplastic detection in biological tissues: When 2D imaging is not enough

The presence of microplastics in the food chain is a public concern worldwide, and its analysis is an analytical challenge. In our research, we apply Raman imaging to study the presence of 1mum polystyrene microplastics in cryosections of Mytilus galloprovincialis due to its wide geographic distribution, widespread occurrence in the food web, and general high presence in the environment. Ingested microplastics are accumulated in the digestive tract, but a large number can also be rapidly eliminated. Some authors state that the translocation of microplastics to the epithelial cells is possible, increasing the risk of microplastics transmission along the food chain. However, as seen in our study, a surface imaging approach (2D) is probably not enough to confirm the internalization of particles and avoid misinterpretation. In fact, while some microplastic particles were detected in the epithelium by 2D Raman imaging, further 3D Raman imaging analysis demonstrated that those particles were dragged from the lumens to the epithelium during sample preparation due to the blade drag effect of the cryotome, and subsequently located on the surface of the analyzed cryosection, discarding the translocation to the epithelial cells. This effect can also happen when the samples are fortuitously contaminated during sample preparation. Several research articles that use similar analytical techniques have shown the presence of microplastics in different types of tissue. It is not our intention to put such results in doubt, but the present work points out the necessity of appropriate three-dimensional analytical methods including data interpretation and the need to go a step further than just surface imaging analysis.This work was funded by Basque Government (KK 2021/00001 ELKARTEK 2021/2022, IT1743-22); MINECO (PID 2020-118685RB-I00, PLASTeMER); further financial support by grant CEX2020-001038-M funded by MCIN/AEI/ 10.13039/50110001103

Multianalytical Approach to explain the darkening process of hematite pigment in paintings from ancient Pompeii after accelerated weathering experiments

[EN] In this paper, recently excavated fresco painting fragments from the House of Marcus Lucretius (Pompeii) and not exposed to the atmosphere since the eruption of the Mount Vesuvius were subjected to a controlled SO2 atmosphere and high relative humidity. These experiments were conducted in order to simulate under accelerated conditions the possible deterioration of the hematite pigment and plaster. The mineralogical transformation of the polychromy and plaster was monitored using mainly Raman spectroscopy, a non-destructive technique, but also infrared spectroscopy (FT-IR) and scanning electron microscopy energy-dispersive X-ray spectroscopy (SEM-EDS). After different exposure cycles to SO2, it was confirmed that hematite red pigment (Fe2O3) can be reduced into magnetite (Fe3O4), which provides the darkened colour to the pigment. While Fe(III) from hematite is reduced into Fe(II) or mixed Fe(III) and Fe(II), the SO2 can be oxidized (SO3) and hydrated to experience a subsequent wet deposition (H2SO4 aerosol) causing also the transformation of calcite into gypsum. Finally, it was assessed that high concentrations of SO2 can also cause the sulphation of hematite pigment promoting its transformation into paracoquimbite/coquimbite (Fe2(SO4)3$9H2O). Moreover, in some areas of the deteriorated painting fragments, non-expected iron(II) sulphate and sulphite species were also identified

Study Of The Soluble Salts Formation In A Recently Restored House Of Pompeii By In-Situ Raman Spectroscopy

The walls and mural paintings of Pompeii exposed directly to the rainfalls are the most impacted in view of the observed decay. However, there are also wall paintings in protected rooms showing evidences of decaying. The aim of this research was to study the salts formed in such protected wall paintings only by non-invasive and in-situ Raman spectroscopy to understand their decaying processes. The perystile of the House of the Gilded Cupids (Regio VI, Insula 16), one of the most important houses of Pompeii was studied. Although an exhaustive restoration was carried out in 2004, a new conservation treatment was needed in 2013 and only two years later, extensive crystallizations of soluble salts were again threatening several of the restored surfaces, thus, the presence of an unsolved degradation pathway was deduced. Thank to the proposed methodology, it was pointed out that the key is the acidified rainfall impact in the non-protected backside of the walls containing the wall paintings. Thus, a new concept in the preservation of the houses of Pompeii is provided, in which the need of the protection of those walls from both sides is suggested to avoid the movement of water through the pores of the walls.The authors would like to thank the direction of Archaeological Park of Pompeii, for the permissions to perform our field studies during the 2015 APUV expedition. This work has been financially supported by the projects DISILICA-1930 (ref: BIA2014-59124) and MADyLIN (ref. BIA2017-87063-P) funded by the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Regional Development Fund (FEDER). Moreover, the sponsorship of the APUV 2015 by BWTEK is also appreciated. Marco Veneranda and Iker Marcaida are grateful for their pre-doctoral grants to the MINECO and Basque government, respectively

Time-course distribution of fluorescent microplastics in target tissues of mussels and polychaetes.

The majority of the plastic produced in the last century is accumulated in the environment, leading to an exacerbated contamination of marine environments due to transport from land to the ocean. In the ocean, mechanical abrasion, oxidation, and photodegradation degrade large plastics into microplastics (MPs) - 0.1mum to 5mm (EFSA, 2016) which are transported through water currents reaching the water surface, water column, and sediments. Further, they can be accumulated by aquatic and benthic species, entering the trophic chain and becoming a potential threat to humans. In the present research, we aimed to decipher the accumulation and distribution time-courses between different organs or target tissues of organisms inhabiting coastal areas such as mussels Mytilus galloprovincialis and polychaetes Hediste diversicolor. Both were exposed in microcosm experiments to fluorescent polystyrene MPs (1mum) which were spiked at two doses (103 and 105 particles/mL) for 1, 4, 24, and 72h. Mussels and polychaetes were digested with 10% KOH and filtered to quantify the number of MPs incorporated. Different anatomical parts of the body were selected and processed for cryosectioning and posterior microscopic localisation of MPs. Both species accumulate MPs spiked in water column, mainly after exposure to the highest dose. In mussels, particles were found in distinct parts of the digestive tract (stomach, digestive diverticula, ducts) and gills. Even if the majority of MPs were localised in the lumen of the digestive tract, in some cases, were inside the digestive epithelium. The identification of MPs and their internalization in the digestive system was studied using Raman spectroscopy. A decreasing trend with time regarding MPs number in the digestive tract (stomach) of mussels was observed while the opposite was recorded for polychaetes and sediments. The combination of microscopical observations of frozen sections and Raman, appeared to be accurate methodologies to address MPs abundances and to reveal their localisation in different organs. This work has enabled to understand the distribution and fate of MPs in different environmental compartments and it could contribute to gain knowledge about their impact after ingestion by coastal organisms.This work was funded by MINECO (PID 2020-118685RB-I00, PLASTeMER); Basque Government (KK 2021/00001 ELKARTEK 2021 2022) and Basque Government (IT1743-22)

Development of non-destructive analytical strategies based on Raman spectroscopy and complementary techniques for Mars Sample Return tested on Northwest Africa 1950 Martian meteorite

The Mars Sample Return (MSR) is a near future mission to return samples from the surface of Mars to the Earth. The field operations to carry out data collection, selection of the samples, and sampling procedure, mainly related to the CanMars MSR analog mission, are well-studied and published. In contrast, studies related to the methodology implemented to characterize the mineralogy of the returned samples are scarcer and focused on biosignature detection. This work presents a non-destructive analytical methodology based on Raman microscopy (single point and imaging), micro-energy dispersive X-ray fluorescence imaging analysis, and scanning electron microscopy coupled to energy dispersive spectroscopy that could be used as a first analytical characterization for the Martian samples that will be returned to the Earth in the upcoming MSR mission, before any destructive analysis. The analytical methodology has been tested on a fragment of the Northwest Africa 1950 Martian meteorite, which gives us a mineralogical characterization of the meteorite. This methodology also allowed to define several chemical reactions taking place in some of the mineral phases (olivines and ilmenite) of the meteorite. In addition to the geochemical characterization of the samples, the fact that this methodology allows to assess the chemical transformations in several minerals gives important clues for describing mineral processes and geological evolution that took place on Mars. This work also shows the advantages and disadvantages that each of the techniques employed has when performing a mineralogical characterization, the information that each one can provide and the importance of combining them.This work has been financially supported through the RamOnMars project: “Contribution of the Raman spectroscopy to the exploration of Mars and Martian Moons: ExoMars, Mars 2020, and MMX missions” (Grant ESP2017-87690-C3-1-R), funded by the Spanish Ministry of Science and Innovation (MICINN) and the European Regional Development Fund (FEDER) and by the Spanish Agency for Research (AEI-MINECO/FEDER) through the Project Science and Instrumentation for the Study of (bio)geochemical processes in Mars (Sigue-Mars), Grant no. RED2018-102600-T. C. García-Florentino is grateful to the Basque Government for her Postdoctoral Grant. J. Huidobro is grateful to the Basque Government for her Predoctoral contract. I. Torre-Fdez acknowledges his predoctoral contract from the University of the Basque Country (UPV/EHU). J. Aramendia is grateful to the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 754513 and The Aarhus University Research Foundation for her fellowship. The authors thank the General Service of Electron Microscopy and Materials Microanalysis Laboratory from the SGIker (UPV/EHU, MICINN, GV/EJ, ERDF and ESF) of the University of the Basque Country for their collaboration in the analyses

Development of a Novel Method for the In-Situ Dechlorination of Immovable Iron Elements: Optimization of Cl- Extraction Yield Through Experimental Design

The conservation of iron objects exposed to marine aerosol is threatened by the formation of akaganeite, a highly unstable Cl-bearing corrosion phase. As akaganeite formation is responsible of the exfoliation of the rust layer, chlorides trigger a cyclic alteration phenomenon that often ends with the total consumption of the iron core. To prevent this degradation process, movable iron elements (e.g. archaeometallurgical artefacts) are generally immersed in alkaline dechlorination baths. Aiming to transfer this successful method to the treatment of immovable iron objects, we propose the in-situ application of alkaline solutions through the use of highly absorbent wraps. As first step of this novel research line, the present work defines the best desalination solution to be used and optimizes its extraction yield. After literature review, a screening experimental design was performed to understand the single and synergic effects of common additives used for NaOH baths. Once the most effective variables were selected, an optimization design was carried out to determine the optimal conditions to be set during treatment. According to the experimental work here presented, the use of 0.7 M NaOH solutions applied at high temperatures (above 50 °C) is recommended. Indeed, these conditions enhance chloride extraction and iron leaching inhibition, while promoting corrosion stabilization.This work has been funded by the DEMORA project (Grant No. PID2020-113391GB-I00), funded by the Spanish Agency for Research (through the Spanish Ministry of Science and Innovation, MICINN, and the European Regional Development Fund, FEDER)

The potential of in situ Raman spectroscopy in the study of the health of cement-based materials of modern buildings during restoration works

Although Raman spectroscopy is a common technique for the analysis of cement-based materials in the research studies or in the field of Cultural Heritage to carried out multianalytical studies, it is not generally used as unique technique of a research or to carry out analysis during ordinary restoration works of modern urban buildings affected by environmental stressors. The disadvantages associated with Raman spectroscopy as fluorescence limits its implementation beyond research studies, more in the case of in situ equipment. However, the technological development allows high-quality results with in situ equipment, so its use could be useful during restoration works. Thus, this work demonstrates how the implementation of the correct methodology could lead to useful and fast results during restoration works. The proposed methodology is based on the use of in situ analysis (screening) on the scaffolding, followed by the sampling of layers based on the previous screening and a posterior exhaustive laboratory analysis. The research has been conducted during the restoration works of a reinforced concrete building in which the attack of atmospheric acid gases (CO2, SO2, and NOx) was identified as the main affection suffered, and the fixed sulfates were the most important intermediary compounds of decaying processes. Many of the pollutants and decaying compounds were even identified during the in situ analysis, improving the anticipation and responsiveness. Therefore, this methodology allows the understanding of the chemistry of the materials to evaluate its health state in a fast and reliable way.Spanish Agency for Research AEI (MICINN/FEDER-UE), Grant/Award Number: PID2020-113391GB-I0

Biochemical and Metabolomic Changes after Electromagnetic Hyperthermia Exposure to Treat Colorectal Cancer Liver Implants in Rats

Background: Hyperthermia (HT) therapy still remains relatively unknown, in terms of both its biological and therapeutic effects. This work aims to analyze the effects of exposure to HT, such as that required in anti-tumor magnetic hyperthermia therapies, using metabolomic and serum parameters routinely analyzed in clinical practice. Methods: WAG/RigHsd rats were assigned to the different experimental groups needed to emulate all of the procedures involved in the treatment of liver metastases by HT. Twelve hours or ten days after the electromagnetic HT (606 kHz and 14 kA/m during 21 min), blood samples were retrieved and liver samples were obtained. 1H-nuclear-magnetic-resonance spectroscopy (1H-NMR) was used to search for possible diagnostic biomarkers of HT effects on the rat liver tissue. All of the data obtained from the hydrophilic fraction of the tissues were analyzed and modeled using chemometric tools. Results: Hepatic enzyme levels were significantly increased in animals that underwent hyperthermia after 12 h, but 10 d later they could not be detected anymore. The metabolomic profile (main metabolic differences were found in phosphatidylcholine, taurine, glucose, lactate and pyruvate, among others) also showed that the therapy significantly altered metabolism in the liver within 12 h (with two different patterns); however, those changes reverted to a control-profile pattern after 10 days. Conclusions: Magnetic hyperthermia could be considered as a safe therapy to treat liver metastases, since it does not induce irreversible physiological changes after application.The authors gratefully acknowledge the financial support from the Agencia Estatal De Investigación (AEI) of Spain and the European Regional Development Fund (ERDF) through project CTM2017-84763-C3-1-R and from the Basque Government through project IT-742-13. M.I. is grateful to the University of the Basque Country (EHU/UPV) for her pre- and post-doctoral fellowships and to the Foundation of Jesus de Gangoiti Barrera

Itsas ingurumenerako mikrokutsatzaile organiko hidrofobikoen presentzia eta eraginak aztertzeko estrategien taxutzea

The efects of hydrophobic microcontaminants such as alkylphenols, organophosphorus compounds, organochloride pesticides, phthalates and musk fragances were studied in mussels. The proposed analytical strategy is based on the combination of passive sampling studies, bioconcentration measurements of micropollutants in mussels, environmental NMR metabolomics of two tissues (gonad, muscle) and hemolymph of mussels and histological analysis. By means of this work, it was verified the feasibility of this strategy in controlled conditions with intent to use it in future environmental studies. The micropollutants mixture was responsible of early spawning in mussels. In fact, the most significant metabolic changes were observed in the same day that spawning took place.; Lan honetan, ingurumen analisirako metodologia planteamendu berri bat proposatu da. Horretarako, kimikariek eta biologoek baldintza kontrolatuetako esposizioa egiteko elkarlanean jardun genuen. Esperimentu honetan, muskuiluak eta lagin-biltze pasiboko tresnak hainbat mikrokutsatzaile hidrofoboren eraginpean jarri ziren. Batetik, kutsatzaileen kontzentrazioak neurtu ziren, lagin-biltze puntualen zein lagin-biltze pasiboen bitartez. Bestetik, muskuiluetan kutsatzaileen kontzentrazioak neurtu ziren. Biologoek, euren aldetik, muskuiluen azterketa histopatologikoa egin zuten. Azkenik, NMR-n oinarritutako metabolomika erabili zen muskuiluek kutsatzaileen aurrean ematen zuten erantzuna aztertzeko. Lau estrategien konbinazioarekin, kausa (kokteleko mikrokutsatzaileen kontzentrazioak eta muskuiluek metatutakoa) eta eragindako efektuak (histologia azterketetan behatutakoak) hobeto uler ditzakegu. Kutsatzaileek eragiten dituzten aldaketak ulertzeko eta ondorioak azaltzeko metabolomika baliabide erabilgarria dela ondorioztatu genuen. Kutsatzaileen koktelak errute goiztiarra eragin zien muskuiluei; izan ere, NMR metabolomika erabiliz, aldaketa metaboliko nabarienak errute-egunean ikusi ziren