Traces under nails in clinical forensic medicine: not just DNA.

When dealing with complex crimes such as rape and assault, every trace takes on an essential role. The hands are often the only means of defence and offence for the victim as well as a frequent area of contact with the environment; fingernails of a victim are a well-known possible source of DNA of the aggressor; nevertheless, they are more rarely treated as an area of interest for non-genetic material, particularly on living victims. The hyponychium, because of its physiological protective function, lends itself ideally to retaining different kinds of traces representative of an environment or various products and substrates that could shed light on the environment and objects involved in the event. We therefore tested how far this capability of the hyponychium could go by simulating the dynamics of contamination of the nail through scratching on different substrates (brick and mortar, painted wood, ivy leaves, cotton and woollen fabric, soil) and persistence of any contaminant at different time intervals. We have thus shown how these traces may remain in the living for up to 24 h after the event using inexpensive and non-destructive techniques such as the episcopic and optical microscope.

Multi-Modal Compositional Analysis of Layered Paint Chips of Automobiles by the Combined Application of ATR-FTIR Imaging, Raman Microspectrometry, and SEM/EDX.

For the forensic analysis of multi-layered paint chips of hit-and-run cars, detailed compositional analysis, including minor/trace chemical components in the multi-layered paint chips, is crucial for the potential credentials of the run-away car as the number of layers, painting process, and used paints are quite specific to the types of cars, color of cars, and their surface protection depending on the car manufacturer and the year of manufacture, and yet overall characteristics of some paints used by car manufacturers might be quite similar. In the present study, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) imaging, Raman microspectrometry (RMS), and scanning electron microscopy/energy-dispersive X-ray spectrometric (SEM/EDX) techniques were performed in combination for the detailed characterization of three car paint chip samples, which provided complementary and comprehensive information on the multi-layered paint chips. That is, optical microscopy, SEM, and ATR-FTIR imaging techniques provided information on the number of layers, physical heterogeneity of the layers, and layer thicknesses; EDX on the elemental chemical profiles and compositions; ATR-FTIR imaging on the molecular species of polymer resins, such as alkyd, alkyd-melamine, acrylic, epoxy, and butadiene resins, and some inorganics; and RMS on the molecular species of inorganic pigments (TiO2, ZnO, Fe3O4), mineral fillers (kaolinite, talc, pyrophyllite), and inorganic fillers (BaSO4, Al2(SO4)3, Zn3(PO4)2, CaCO3). This study demonstrates that the new multi-modal approach has powerful potential to elucidate chemical and physical characteristics of multi-layered car paint chips, which could be useful for determining the potential credentials of run-away cars.

Eco-friendly non-biocide-release coatings for marine biofouling prevention.

Environmental concerns have been changing the way of looking for solutions to problems. The hydrosphere, together with its biosphere, has been feeling the impact of many pollutants, used for instance in the marine industry for economic reasons or lack of knowledge of their effects. In particular biocides, applied as coatings in paints, are released into the waters becoming toxic and persistent extending their action to an area far beyond the initial coated surface they should protect. In order to minimize these side effects, two biocides, Irgarol (I) and Econea (E), were covalently attached to polyurethane (PU) and foul-release silicone based (PDMS) marine paints through an isocyanate linker. Their antifouling bioactivity was better in PDMS coatings, both for single (Econea) and combined biocides (E/I ratio = 1.5) with contents lower than 0.6 wt%. The treated samples remained almost clean after more than one year immersion in the Portuguese shore of the Atlantic Ocean, and after about 24 weeks under the tropical conditions of Singapore (Fouling rate < 1%). Complementary biofilm adhesion susceptibility tests against Pseudoalteromonas tunicata D2 showed adhesion reduction higher than 90% for PU formulations containing single biocides and close to 100% for PDMS with combined biocides. The eco-toxicity assessment evidenced a low environmental impact, in accordance with the European standards. In addition, shipping field trial tests showed the best antifouling performance for the Econea-based PDMS formulations (E = 0.6 wt%), which remained clean for about nine months in open seawaters, proving the efficacy of this non-release strategy, when applied under dynamic conditions.

On the Habitability of Desert Varnish: A Combined Study by Micro-Raman Spectroscopy, X-ray Diffraction, and Methylated Pyrolysis-Gas Chromatography-Mass Spectrometry.

In 2020, the ESA ExoMars and NASA Mars 2020 missions will be launched to Mars to search for evidence of past and present life. In preparation for these missions, terrestrial analog samples of rock formations on Mars are studied in detail in order to optimize the scientific information that the analytical instrumentation will return. Desert varnishes are thin mineral coatings found on rocks in arid and semi-arid environments on Earth that are recognized as analog samples. During the formation of desert varnishes (which takes many hundreds of years), organic matter is incorporated, and microorganisms may also play an active role in the formation process. During this study, four complementary analytical techniques proposed for Mars missions (X-ray diffraction [XRD], Raman spectroscopy, elemental analysis, and pyrolysis-gas chromatography-mass spectrometry [Py-GC-MS]) were used to interrogate samples of desert varnish and describe their capacity to sustain life under extreme scenarios. For the first time, both the geochemistry and the organic compounds associated with desert varnish are described with the use of identical sets of samples. XRD and Raman spectroscopy measurements were used to nondestructively interrogate the mineralogy of the samples. In addition, the use of Raman spectroscopy instruments enabled the detection of ß-carotene, a highly Raman-active biomarker. The content and the nature of the organic material in the samples were further investigated with elemental analysis and methylated Py-GC-MS, and a bacterial origin was determined to be likely. In the context of planetary exploration, we describe the habitable nature of desert varnish based on the biogeochemical composition of the samples. Possible interference of the geological substrate on the detectability of pyrolysis products is also suggested. Key Words: Desert varnish-Habitability-Raman spectroscopy-Py-GC-MS-XRD-ExoMars-Planetary science. Astrobiology 17, 1123-1137.

Identification of plant cells in black pigments of prehistoric Spanish Levantine rock art by means of a multi-analytical approach. A new method for social identity materialization using chaîne opératoire.

We present a new multi-analytical approach to the characterization of black pigments in Spanish Levantine rock art. This new protocol seeks to identify the raw materials that were used, as well as reconstruct the different technical gestures and decision-making processes involved in the obtaining of these black pigments. For the first of these goals, the pictorial matter of the black figurative motifs documented at the Les Dogues rock art shelter (Ares del Maestre, Castellón, Spain) was characterized through the combination of physicochemical and archeobotanical analyses. During the first stage of our research protocol, in situ and non-destructive analyses were carried out by means of portable Energy Dispersive X-Ray Fluorescence spectrometry (EDXRF); during the second stage, samples were analyzed by Optical Microscopy (OM), Raman spectroscopy, and Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy (SEM-EDX). Two major conclusions have been drawn from these analyses: first, charred plant matter has been identified as a main component of these prehistoric black pigments; and second, angiosperm and conifer charcoal was a primary raw material for pigment production, identified by means of the archaeobotanical study of plant cells. For the second goal, black charcoal pigments were replicated in the laboratory by using different raw materials and binders and by reproducing two main chaînes opératoires. The comparative study of the structure and preservation of plant tissues of both prehistoric and experimental pigments by means of SEM-EDX underlines both a complex preparation process and the use of likely pigment recipes, mixing raw material with fatty or oily binders. Finally, the formal and stylistic analysis of the motifs portrayed at Les Dogues allowed us to explore the relationship between identified stylistic phases and black charcoal pigment use, raising new archaeological questions concerning the acquisition of know-how and the transfer of traditionally learned chaînes opératoires in Spanish Levantine rock art.

Assessment of airborne nanoparticles present in industry of aluminum surface treatments.

Conventional industrial processes are emission sources of unintended nanoparticles which are potentially harmful for the environment and human health. The aim of this study is to assess airborne nanoparticle release from aluminum surface treatment processes in various workplaces. Two direct reading instruments, a scanning mobility particle sizer to measure size distribution and a nanoparticle surface area monitoring to measure the surface area of particles deposited in the human lung, were employed to perform area monitoring. The lacquering paint was the process which released the highest concentration of particles from 10-487 nm (7.06 × 106 particles/cm3). The lacquering baths process emitted particles of the largest average size (76.9 nm) and the largest surface area deposited in the human lung (167.4 µm2/cm3). Conversely, the anodizing bath process generated particles of the smallest average size (44.3 nm) and the lowest human lung-deposited surface area (1.2 µm2/cm3). The total number of particles and the surface area can only be fairly correlated for environments in which the surface area presented higher values. The transmission electron microscopy analysis confirmed the presence of aluminum oxide particles of different dimensions near the LB and AB areas and polymeric-based particles near the LP areas. The findings of this study indicated that lacquering and anodizing surface treatments are indeed responsible for the emission of airborne nanoparticles. It also highlights the importance of control strategies as a means of protecting workers' health and environment.

Model study of modern oil-based paint media by triacylglycerol profiling in positive and negative ionization modes.

Lipid binders have traditionally been determined in paintings by using gas chromatography/mass spectrometry (GC/MS) to identify the characteristic profiles and ratios of fatty acids . However, the presence of mixtures in contemporary and modern oil paints makes the GC/MS determination of fatty acids insufficient to fully characterize the lipid binding media. In this study we prove that triacylglycerol (TAG) profiling by high-performance liquid chromatography with high-resolution tandem mass spectrometry, using ESI in positive and negative ionization modes is highly effective. We exploited this analytical approach to study the curing and degradation processes undergone by six plant oils used in the formulation of media in modern paints, using both natural and artificial ageing experiments. We believe that is the first time that a negative ionization mode has been applied for this purpose and that a survey with HPLC-ESI-Q-ToF has been carried out to study the ageing kinetics of plant oils. TAG profiling enabled us to study the evolution over time of the constituents of modern oils, with respect to curing and ageing. The data analyzed in this study demonstrate that our approach is efficient to study the oxidation of TAGs during ageing. The data also improve current knowledge on the properties of vegetable oils, which could lead to the development of new paint materials and conservation treatments for modern and contemporary works of art.

A Unique Collection of Palaeolithic Painted Portable Art: Characterization of Red and Yellow Pigments from the Parpalló Cave (Spain).

In this work we analyze the pigments used in the decoration of red and yellow motifs present in the portable art of the Parpalló Cave (Gandía, Spain), one of the most important Palaeolithic sites in the Spanish Mediterranean region. Energy dispersive X-ray fluorescence spectrometry (EDXRF) and spectrophotometry in the visible region (CIEL*a*b*color coordinates and spectral reflectance curves) were used to perform in situ fast analyses of the red and yellow motifs with portable equipment and to characterize their elemental composition and their colorimetric perception, respectively. According to the elemental composition, the intensity of the fluorescence iron signals in red and yellow motifs are higher than average values in the rock substrates. As expected, red motifs possess high values of the chromatic coordinate a* and yellow motifs possess high values of b*. This characterization was complemented with FT-IR analyses of microsamples detached from the red and yellow colored zones of a small set of plaquettes. Our results show that the artists used red and yellow pigments in the decoration likely derived from natural iron oxides as hematite and goethite.

Portable Raman, DRIFTS, and XRF Analysis to Diagnose the Conservation State of Two Wall Painting Panels from Pompeii Deposited in the Naples National Archaeological Museum (Italy).

This work presents a methodology that combines spectroscopic speciation, performed through portable Raman spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and energy dispersive X-ray fluorescence spectrometry (ED-XRF) working in situ, and thermodynamic speciation to diagnose the environmental impacts, induced by past and current events, on two wall painting panels (Nos. 9103 and 9255) extracted more than 150 years ago from the walls of a Pompeian house (Marcus Lucretius House, Regio IX, Insula 3, House 5/24) and deposited in the Naples National Archaeological Museum (MANN). The results show a severe chemical attack of the acid gases that can be explained only by the action of H2S during and just after the eruption of the Vesuvius volcano, that expelled a high concentration of sulfur gases. This fact can be considered as the most important process impacting the wall painting panels deposited in the museum, while the rain-wash processes and the colonization of microorganisms have not been observed in contrast to the impacts shown by the wall paintings left outside in the archaeological site of Pompeii. Moreover, the systematic presence of lead traces and strontium in both wall paintings suggests their presence as impurities of the calcite mortars (intonacco) or calcite binder of these particular fresco Pompeian murals.

Alteración anatómica orbitaria en Retrato de familia. Adriaen Thomasz Key. Museo Nacional del Prado, Madrid / Orbital anatomical changes in Retrato de familia. Adriaen Thomasz Key. El Prado National Museum, Madrid

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Studying the effect of antioxidants on cytogenetic manifestations of solvent exposure in the paint industry.

OBJECTIVE: To investigate the antioxidant role in reversing cytogenetic changes caused by solvent exposure in paint industry. SUBJECTS AND METHODS: A prospective controlled clinical trial was performed on 39 workers exposed to solvents and 39 workers not exposed to solvents by supplying a mixture of antioxidant vitamins (A, C, E and selenium) and the after effects of such regimen were analyzed. Environmental monitoring was carried out for air concentrations of different solvents at workplace. Exposed group was cytogenetically tested before and after giving the mixture of antioxidant vitamins for 1 month duration. RESULTS: Frequency of chromosomal aberrations (CAs) and the mean of sister chromatid exchanges (SCEs) were statistically significantly higher among exposed workers than among controls. After the supplementation of antioxidants, there was a statistically significant decrease in the frequency of CAs, and 88% abnormal levels of SCEs were back to normal levels. CONCLUSION: Antioxidant supplementation decreases the frequency of CAs and SCEs among exposed workers.

Micro-Raman analysis of the pigments on painted pottery figurines from two tombs of the Northern Wei Dynasty in Luoyang.

The pigments on the painted pottery figurines from two tombs of Northern Wei Dynasty (AD 386-534) in Luoyang were analyzed by Raman microscopy. All the pigments were identified compared with the Raman spectra of standard pigments. The red pigments were identified as haematite, the blue pigment as lapis lazuli, the green pigment as malachite, the black pigment as carbon black and the white pigment as calcite. Similar pigments were used in the two tombs despite the pottery figurines were very different in artistic style. The use of lapis lazuli as blue pigment on Chinese painted pottery figurines was found for the first time. This pigment and the painted pottery figurine of Sogdians are of great archaeological significance because it demonstrated that the trade and cultural exchanges via the Silk Road had extended to Luoyang city in the Northern Wei Dynasty. The result also confirms that micro-Raman spectroscopy is a powerful analytical method for the identification of pigments on ancient artworks.

New insights into the ageing of linseed oil paint binder: a qualitative and quantitative analytical study.

This paper presents an analytical investigation of paint reconstructions prepared with linseed oil that have undergone typical 19th century treatments in preparation for painting. The oil was mechanically extracted from the same seed lot, which was then processed by various methods: water washing, heat treatments, and the addition of driers, with and without heat. A modern process lead white (Dutch source, Schoonhoven) and a commercially available vine black were used as pigments. The reconstructions were prepared in 1999, and naturally aged from then onwards. We compared thermogravimetric analysis (TG), which yields macromolecular information, with gas chromatography-mass spectrometry (GC-MS) and direct exposure mass spectrometry (DEMS), which both provide molecular information. The study enabled us to quantitatively demonstrate, for the first time, that the parameters used to identify drying oils are deeply influenced by the history of the paint. In particular, here we show that the ratio between the relative amounts of palmitic and stearic acid (P/S), which is used as an index for differentiating between drying oils, is extremely dependent on the pigments present and the age of the paint. Moreover the study revealed that neither the P/S parameter nor the ratios between the relative amounts of the various dicarboxylic acids (azelaic over suberic and azelaic over sebacic) can be used to trace the sorts of pre-treatment undergone by the oil investigated in this study. The final results represent an important milestone for the scientific community working in the field, highlighting that further research is still necessary to solve the identification of drying oils in works of art.

Analytical Raman spectroscopic discrimination between yellow pigments of the Renaissance.

The Renaissance represented a major advance in painting techniques, subject matter, artistic style and the use of pigments and pigment mixtures. However, most pigments in general use were still mineral-based as most organic dyes were believed to be fugitive; the historical study of artists' palettes and recipes has assumed importance for the attribution of art works to the Renaissance period. Although the application of diagnostic elemental and molecular spectroscopic techniques play vital and complementary roles in the analysis of art works, elemental techniques alone cannot definitively provide the data needed for pigment identification. The advantages and limitations of Raman spectroscopy for the definitive diagnostic characterisation of yellow pigments that were in use during the Renaissance is demonstrated here in consideration of heavy metal oxides and sulphides; these data will be compared with those obtained from analyses of synthetic yellow pigments that were available during the eighteenth and nineteenth Centuries which could have been used in unrecorded restorations of Renaissance paintings.

Spectrofluorimetric study of the ageing of mixtions used in the gildings of mediaeval wall paintings.

INTRODUCTION: In the Middle Ages, we could find gildings on mural paintings. Gold, silver or tin leaves were applied according to distemper or mixtion technique. For the first one, a binder as glue is necessary, and for the second, a lipidic binder is used to stick the metallic leaf. Studies of gildings materials characterization show that the mixtion technique, with a mordant, is the most common. Linseed oil seems to be the binder used. It is always mixed with a siccative agent as lead. Because of bad conditions of conservation, the gildings do not resist anymore, only remain traces of metal or the adhesive under-layer. Thanks to the binder fluorescence, we can nowadays detect ancient gildings. OBJECTIVE: The purpose of this paper is to study the degradation of the linseed oil, generally mixed with lead white to give a mordant for the metallic leaf, by spectrofluorimetry. MATERIALS AND METHODS: To understand in situ fluorescence, gildings recreations, linseed oil and lead white are aged in hydro-thermal and ultraviolet (UV) light (313 nm) climatic rooms and under UV irradiation. Irradiation wavelengths are chosen according to the maximum of absorption of linseed oil and the bibliography (296, 313 and 366 nm = mercury bands). RESULTS: In comparison with results (in situ UV lamp, spectrofluorimetry), excitation wavelength chosen is 366 nm. Irradiations at 366 nm of linseed oil and linseed oil mixed with lead white show the most degrading effect in the fluorescence to the big wavelength. Lead white plays an important siccative role; it increases the intensity fluorescence and accelerates the drying of linseed oil. This study also allows to show that 366 nm wavelength is good for the in situ observation.

A multi-analytical approach for the identification of aloe as a colorant in oil-resin varnishes.

Aloe plants have been widely documented in artists' treatises dating from the sixteenth to the nineteenth century as a source of colorant to achieve lustrous golden glazes on tin- and silver-foiled objects and warm-toned finishes on musical instruments, such as violins. Aloe extracts contain characteristic anthraquinone and phenolic components which impart a distinctive orange tone and fluorescence to mixtures containing them. Because of the low concentration of colorant in the coatings and its probable degradation by high temperature during manufacture, the identification of aloe in heated oil-resin mixtures represents an analytical challenge. For this reason, the possible presence of aloe in glazes and coatings has been largely overlooked. This paper describes various analytical approaches to the identification of aloe in historic samples, from comparison with results obtained from reference standards and mock-up samples. Complementary analytical techniques including thermally assisted hydrolysis and methylation-gas chromatography-mass spectrometry, high-performance liquid chromatography, laser desorption-mass spectrometry, matrix-assisted laser desorption-ionization-mass spectrometry and surface-enhanced Raman scattering were used. Different chemical markers were identified by the individual methods and the advantages and limitations of each technique for the identification of aloe in oil-resin varnishes are discussed.

Development of karanja oil based offset printing ink in comparison with linseed oil.

The conventional offset lithographic printing ink is mainly based on linseed oil. But in recent years, due to stiff competition from synthetic substitutes mainly from petroleum products, the crop production shrinks down to an unsustainable level, which increases the price of linseed oil. Though soyabean oil has replaced a major portion of linseed oil, it is also necessary to develop alternate cost effective vegetable oils for printing ink industry. The present study aims to evaluate the performance of karanja oil (Pongamia glabra) as an alternative of linseed oil in the formulation of offset printing ink because karanja oil is easily available in rural India. Physical properties of raw karanja oil are measured and compared with that of alkali refined linseed oil. Rosin modified phenolic resin based varnishes were made with linseed oil as well as with karanja oil and their properties are compared. Sheetfed offset inks of process colour yellow and cyan is chosen to evaluate the effect of karanja oil in ink properties. In conclusion, karanja oil can be accepted as an alternate vegetable oil source with its noticeable effect on print and post print properties with slower drying time on paper. However, the colour and odour of the oil will restrict its usage on offset inks.

ATR-FT-IR spectroscopy in the region of 550-230 cm(-1) for identification of inorganic pigments.

A comprehensive study of ATR-FT-IR spectra of 40 inorganic pigments of different colours widely used in historical paintings has been carried out in the low wave number spectral range (550-230 cm(-1)). The infrared spectra were recorded from mixtures of pigment and linseed oil. It is demonstrated that this spectral range - essentially devoid of absorption peaks of the common binder materials - can be well used for identification of inorganic pigments in paint samples thereby markedly extending the possibilities of pigment identification/confirmation by ATR-IR spectroscopy into the realm of pigments having no absorptions in the mid-IR region. In some cases the method can be used alone for pigment identification and in many cases it provides useful additional evidence for pigment identification using other instrumental techniques (electron microprobe analysis, XRF, optical microscopy). Together with earlier work this study provides a comprehensive overview of the pigment identification possibilities using ATR-FT-IR as well as a collection of reference spectra and is expected to be a useful reference for conservation practitioners.

Preliminary study of UV ageing process of proteinaceous paint binder by FT-IR and principal component analysis.

This work presents a preliminary study on the ageing process of proteinaceous binder materials used in painting under UV light. With this aim, two sets of model samples were prepared: samples prepared using a single protein material and complex samples prepared in a similar way to the sequence of layers in a real painting from lowest to highest complexity (protein, drying oils, pigment and varnish). The study focuses on acquiring information about the possible degradation process of proteinaceous binders due to ageing and how this process be affected by the presence of characteristic non-proteinaceous painting materials, such as lipids from linseed oil, terpenic compounds from varnish and inorganic pigments. Samples simulated the accelerated ageing process, as did the UV light exposition. The FT-IR spectra were recorded after 100, 500, 1000 and 1500 h of exposition. The study of the accelerated ageing process was performed by means of principal component analysis (PCA) using the FT-IR spectra obtained. Loadings from the significant principal components were analysed to find the FT-IR frequency (cm(-1)) involved in the degradation process. The study showed the lack of any relevant modification on the proteins in the single model samples. On the contrary, the complex model samples showed the ageing process. The accelerated ageing process can be explained by a principal component from PCA. The most affected IR region was 2900-3600 cm(-1), where the amide band was included.

Silver-nanoparticle-embedded antimicrobial paints based on vegetable oil.

Developing bactericidal coatings using simple green chemical methods could be a promising route to potential environmentally friendly applications. Here, we describe an environmentally friendly chemistry approach to synthesize metal-nanoparticle (MNP)-embedded paint, in a single step, from common household paint. The naturally occurring oxidative drying process in oils, involving free-radical exchange, was used as the fundamental mechanism for reducing metal salts and dispersing MNPs in the oil media, without the use of any external reducing or stabilizing agents. These well-dispersed MNP-in-oil dispersions can be used directly, akin to commercially available paints, on nearly all kinds of surface such as wood, glass, steel and different polymers. The surfaces coated with silver-nanoparticle paint showed excellent antimicrobial properties by killing both Gram-positive human pathogens (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). The process we have developed here is quite general and can be applied in the synthesis of a variety of MNP-in-oil systems.