“Synchrotron radiation induced X-ray microfluorescence analysis”. Janssens K, Vincze L, Vekemans B, Aerts A, Adams F, Jones KW, Knöchel A, Microchimica acta
T2 –, 4th Workshop of the European-Microanalysis-Society on Modern, Developments and Applications in Microbeam Analysis, MAY, 1995, ST MALO, FRANCE , 87 (1996)
Abstract: mu-XRF is the microscopic equivalent of the well-established multielement analytical technique. In this paper, after comparing the interaction of X-ray photons, electrons and protons with matter and an introduction to synchrotron rings and microfocussing of X-rays, the instrumentation for mu-XRF is discussed, both for laboratory source and synchrotron based setups and the analytical characteristics of mu-XRF are contrasted to that of other microanalytical techniques, Also, this issue of quantification of mu-XRF data is addressed; the applicability of the method in archeological and geological analysis is illustrated.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“The development process of an expert system for the automated interpretation of large epma data sets”. Janssens K, Dorrine W, van Espen P, Chemometrics and intelligent laboratory systems 4, 147 (1988). http://doi.org/10.1016/0169-7439(88)80086-8
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Chemometrics (Mitac 3)
DOI: 10.1016/0169-7439(88)80086-8
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“Trace-level micro-XANES by means of bending magnets radiation focused with a polycapillary lens”. Vincze L, Janssens K, Wei F, Proost K, Vekemans B, Vittiglio G, Yan Y, Falkenberg G (1999).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Trace-level microanalysis of Roman glass from Khirbet Qumran, Israel”. Aerts A, Janssens K, Adams F, Journal of archaeological science 26, 883 (1999). http://doi.org/10.1006/JASC.1999.0397
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.602
DOI: 10.1006/JASC.1999.0397
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“Un verre méditerranéen pour la production de bracelets laténiens en Europe septentrionale : résultats danalyses SEM-EDX et LA-ICP-MS de bracelets en verre La Tène tardive de Odijk, Tiel et Geldermalseren-Hondsgemet”. Cosyns P, Cagno S, Janssens K, Nys K, Bulletin AFAV , 13 (2014)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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De Vis K, Jacobs P, Caen J, Janssens K (2010) The use of glass bricks in architecture in the 19th and 20th centuries : a case study. 194–201
Keywords: P2 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“The use of lead-glass capillaries for microfocusing of highly energetic (0-60 KeV) synchrotron radiation”. Janssens K, Vincze L, Vekemans B, Adams F, Haller M, Knöchel A, Journal of analytical atomic spectrometry 13, 339 (1998). http://doi.org/10.1039/A707700I
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.379
DOI: 10.1039/A707700I
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“Use of microscopic XRF for non-destructive analysis in art an archaeometry”. Janssens K, Vittiglio G, Deraedt I, Aerts A, Vekemans B, Vincze L, Wei F, de Ryck I, Schalm O, Adams F, Rindby A, Knöchel A, Simionovici AS, Snigirev A, X-ray spectrometry 29, 73 (2000). http://doi.org/10.1002/(SICI)1097-4539(200001/02)29:1<73::AID-XRS416>3.3.CO;2-D
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.298
DOI: 10.1002/(SICI)1097-4539(200001/02)29:1<73::AID-XRS416>3.3.CO;2-D
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“The use of scanning X-ray microprobe for simultaneous XRF/XRD studies of fly-ash particles”. Rindby A, Engström P, Janssens K, Journal of synchotron radiation 4, 228 (1997)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“The use of synchrotron micro-XRF for characterisation of the micro-heterogeneity of low-Z reference materials”. Kempenaers L, Vincze L, Janssens K, Spectrochimica acta: part B : atomic spectroscopy 55, 651 (2000). http://doi.org/10.1016/S0584-8547(00)00207-X
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.241
DOI: 10.1016/S0584-8547(00)00207-X
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“The use of synchrotron micro-XRF for characterisation of the micro-heterogeneity of low-Z reference materials containing heavy metals”. Kempenaers L, Vincze L, Janssens K (1999).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“X-ray based methods of analysis”. Janssens K page 129 (2004).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“X-ray fluorescence analysis”. Janssens K (2003).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“X-ray fluorescence microtomography”. Chukalina M, Simionovici AS, Snigirev A, Drakopoulos M, Snigireva I, Adams F, Janssens K, Poverhnost 3, 40 (2001)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“X-ray fluorescence microtomography: experiment and reconstruction”. Simionovici AS, Chukalina M, Drakopoulos M, Snigireva I, Snigirev A, Schroer C, Lengeler B, Janssens K, Adams F page 304 (1999).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“X-ray microanalysis: a new tool for environmental analysis”. Adams F, Janssens K page 183 (1996).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“X-ray optics for synchrotron-radiation-induced X-ray micro fluorescence at the european synchrotron-radiation facility, Grenoble”. Vincze L, Janssens K, Adams F, Institute of physics conference series , 613 (1993)
Abstract: Different optical designs for generating synchrotron x-ray micro beams suitable for use in an X-ray fluorescence microscope using an ESRF bending magnet X-ray source are compared. Attention is devoted to the spatial and energy distribution of the photons in the micro beam and to the minimum detection limits that are achievable with each alternative optical system.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“μ-XANES speciation of Zn in rhizospheric soil and in edible plants grown on a polluted soil amended with compost”. Terzano R, al Chami Z, Vekemans B, Janssens K, Miano T, Ruggiero P (2007).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“XRS activities at the Micro &, Trace Analysis Centre (MiTAC), University of Antwerp, Belgium”. Padilla R, Janssens K, van Espen P, Van Grieken R, IAEA XRF newsletter 12, 13 (2006)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Chemometrics (Mitac 3)
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“Young Anthony van Dyck revisited : a multidisciplinary approach to a portrait once attributed to Peter Paul Rubens”. Van der Stighelen K, Janssens K, van der Snickt G, Alfeld M, Van Beneden B, Demarsin B, Proesmans M, Marchal G, Dik J, Art matters : international journal for technical art history 6, 21 (2014)
Abstract: Part of the collection of the Rubens House in Antwerp is a portrait of young Anthony van Dyck, alternatively attributed to Peter Paul Rubens and his pupil Anthony van Dyck. In order to reconstruct the genesis of the portrait in a manner that improves upon past investigations, a number of high-end technological methods, such as X-radiography, X-ray computer tomography, mammographic tomosynthesis and macroscopic X-ray fluorescence, have been employed to render the overpainted layers visible again. The results of the interdisciplinary examinations of the portrait of the youthful Van Dyck are impressive. The combined results allow the later additions to be peeled away until the original composition can be reached. Several pentimenti are easily discernible and refer to a rather immature hand that makes the authorship of Peter Paul Rubens very unlikely. What emerges is a portrait of an ambitious young man with a luxuriant head of hair and a slightly turned-up collar. The hat and cape were added later. The facial features are more recognisable and the execution of the bold curls points irrefutably in the direction of Anthony van Dyck as the author of his own portrait.
Keywords: A3 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“2D X-ray and FTIR micro-analysis of the degradation of cadmium yellow pigment in paintings of Henri Matisse”. Pouyet E, Cotte M, Fayard B, Salome M, Meirer F, Mehta A, Uffelman ES, Hull A, Vanmeert F, Kieffer J, Burghammer M, Janssens K, Sette F, Mass J, Applied physics A : materials science &, processing 121, 967 (2015). http://doi.org/10.1007/S00339-015-9239-4
Abstract: The chemical and physical alterations of cadmium yellow (CdS) paints in Henri Matisse's The Joy of Life (1905-1906, The Barnes Foundation) have been recognized since 2006, when a survey by portable X-ray fluorescence identified this pigment in all altered regions of the monumental painting. This alteration is visible as fading, discoloration, chalking, flaking, and spalling of several regions of light to medium yellow paint. Since that time, synchrotron radiation-based techniques including elemental and spectroscopic imaging, as well as X-ray scattering have been employed to locate and identify the alteration products observed in this and related works by Henri Matisse. This information is necessary to formulate one or multiple mechanisms for degradation of Matisse's paints from this period, and thus ensure proper environmental conditions for the storage and the display of his works. This paper focuses on 2D full-field X-ray Near Edge Structure imaging, 2D micro-X-ray Diffraction, X-ray Fluorescence, and Fourier Transform Infra-red imaging of the altered paint layers to address one of the long-standing questions about cadmium yellow alteration-the roles of cadmium carbonates and cadmium sulphates found in the altered paint layers. These compounds have often been assumed to be photo-oxidation products, but could also be residual starting reagents from an indirect wet process synthesis of CdS. The data presented here allow identifying and mapping the location of cadmium carbonates, cadmium chlorides, cadmium oxalates, cadmium sulphates, and cadmium sulphides in thin sections of altered cadmium yellow paints from The Joy of Life and Matisse's Flower Piece (1906, The Barnes Foundation). Distribution of various cadmium compounds confirms that cadmium carbonates and sulphates are photo-degradation products in The Joy of Life, whereas in Flower Piece, cadmium carbonates appear to have been a [(partially) unreacted] starting reagent for the yellow paint, a role previously suggested in other altered yellow paints.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S00339-015-9239-4
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“Effect of ultra-fine fly ash on concrete performance and durability”. Kara De Maeijer P, Craeye B, Snellings R, Kazemi-Kamyab H, Loots M, Janssens K, Nuyts G, Construction And Building Materials 263, 120493 (2020). http://doi.org/10.1016/J.CONBUILDMAT.2020.120493
Abstract: In the present study ultra-fine fly ash as a novel by-product obtained by a dry and closed separation process was investigated as cement replacement in concrete. The impact of ultra-fine fly ash on material properties was investigated following an upscaling as an approach considering paste, mortar and concrete properties. Two types of cement, Portland cement (CEMI) and slag cement (CEMIII), two types of ultra-fly ashes, one with particle size d90< 9.3lm (FA1) and second with d90< 4.6lm (FA2) were used.At paste- and mortar- level, cement was replaced at 0%, 15%, 25%, 35% and 50% with FA1 and FA2. At concrete- level, cement was replaced at 0%, 15% and 25% with different ratios of FA1 and FA2. The results at paste- and mortar- level showed that an increased fineness of the fly ash (FA2) contributes to better workability of the mix. For CEMI, the compressive strength of concrete with FA2 at 25% cement replacement was already equal to the reference 0% replacement concrete at the age of 28 days. For CEMIII, the compressive strength of concrete mix with FA1 with 15% and FA2 with 25% cement replacements reached the reference concrete value at the age of 91 days. Regarding the durability, replacing cement with ultra-fine fly ash (FA2) had a positive influence on the resistivity, chloride migration coefficient and alkali-silica reaction (ASR), and a negative influence on the carbonation resistance.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Energy and Materials in Infrastructure and Buildings (EMIB)
Impact Factor: 7.4
DOI: 10.1016/J.CONBUILDMAT.2020.120493
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“Combined MA-XRF, MA-XRPD and SEM-EDX analysis of a medieval stained-glass panel formerly from Notre Dame, Paris reveals its material history”. Gestels A, Van der Snickt G, Caen J, Nuyts G, Legrand S, Vanmeert F, Detry F, Janssens K, Steenackers G, Microchemical journal 177, 107304 (2022). http://doi.org/10.1016/J.MICROC.2022.107304
Abstract: As part of its conservation-restoration, the 13th century stained-glass panel ‘the Annunciation’, was examined at the micro- and macro level. This window, since 1898 in the collection of the Museum Mayer Van den Bergh (Antwerp, B), was formerly a part of the southern Rose window of the Notre Dame Cathedral (Paris, F). The insigths emerging from a first phase of the analysis, comprising non-invasive analysis techniques such as optical microscopy combined with macroscopic X-ray fluorescence (MA-XRF) and X-ray diffraction (MA-XRPD) mapping, were used to select sampling positions for the second phase of investigation that involved micro-invasive analysis, namely scanning-electron microscopy coupled to energy-dispersive X-ray analysis (SEM-EDX). The aim of the investigation was fourfold: (1) to assess the applicability of MA-XRF scanning for the characterisation of stained glass windows prior to any conservation or restoration procedure, (2) to assess the applicability of MA-XRPD scanning to identify the degradation products formed on the surface of stained glass windows, (3) to establish a method to limit the set of sampled glass fragments taken from a glass panel for quantititive analysis while maintaining sufficient representativeness and (4) to distinguish the original glass panes and grisaille paint from non-original glass panes that were inserted during various past interventions. Most of the panes in this window proved to consist of medieval potash glass, consistent with the 13th c. origin of the window while a limited number of panes were identified as non-original infills, with divergent glass compositional types and/or colorants. Most panes derive their color from the pot metal glass (i.e. homogenously colored) they were made of. Some of the panes that originally had a red flashed layer on their surface, completely or partially lost this layer due to weathering. Three main compositional glass families with similar color could be defined. With the exception of the yellow and orange panes, the chromophoric elements responsible for the dark(er) and light(er) blue (Co), green (Cu), purple (Mn) and red colors (Cu) were identified. Two different grisaille paints were encountered, part of which were restored during the 19th century. On the basis of this information, all missing pieces were replaced by glass panes with appropriate colors and the panel could be successfully conserved to its former glory. On the surface of several panes, typical glass degradation products such as calcite, syngenite and gypsum were identified, together with lead based degradation products such as anglesite and palmierite. In addition, the presence of hematite and melanotekite in the grisailles was observed; also the presence of Zn, uncorrelated to Cu, in the grissailes on the right side of the window became apparent.
Keywords: A1 Journal article; Engineering sciences. Technology; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 4.8
DOI: 10.1016/J.MICROC.2022.107304
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“Development of a multi-method analytical approach based on the combination of synchrotron radiation X-ray micro-analytical techniques and vibrational micro-spectroscopy methods to unveil the causes and mechanism of darkening of “fake-gilded&rdquo, decorations in a Cimabue painting”. Monico L, Prati S, Sciutto G, Catelli E, Romani A, Balbas DQ, Li Z, De Meyer S, Nuyts G, Janssens K, Cotte M, Garrevoet J, Falkenberg G, Tardillo Suarez VI, Tucoulou R, Mazzeo R, Journal of analytical atomic spectrometry 37, 114 (2022). http://doi.org/10.1039/D1JA00271F
Abstract: Redox processes activated by environmental factors have been identified as the main cause of the chromatic alterations of a number of artists' pigments, including the yellow pigment orpiment (As2S3). Although a general comprehension of the mechanisms has been provided through characterization of degradation compounds of As2S3, experimental evidences to prove how other paint components and how different environmental agents influence the formation pathways of specific secondary compounds are still lacking. Thus, it becomes fundamental to develop a methodological strategy which enable achieving a discrimination among the causes affecting the chemical stability of more heterogenous As2S3-based paints and defining the mechanism through which the alteration establishes and evolves, with the ultimate goal of optimizing the preventive conservation measures of unique masterpieces. In this paper, we propose a comprehensive multi-material and multi-method approach based on the combination of synchrotron radiation X-ray micro-analytical techniques (i.e., X-ray diffraction, X-ray fluorescence and X-ray absorption near edge structure spectroscopy at S K-/Ag L-3-/As K-edges) and vibrational micro-spectroscopy methods to unveil the causes and mechanism of darkening of “fake-gilded” decorations in tempera paintings, originally consisting of an unusual mixture of As2S3 and metallic silver (Ag-0). Such degradation process is a not yet understood phenomenon threatening a series of Old Master paintings, including those by the Italian painters Cimabue and Pietro Lorenzetti. The high specificity, sensitivity and lateral resolution of the employed analytical methods allowed providing first-time evidence for the presence of black acanthite (alpha-Ag2S), mimetite [Pb-5(AsO4)(3)Cl] and syngenite [K2Ca(SO4)(2)center dot H2O] as degradation products of the “fake-gilded” decorations in the Maesta by Cimabue (Church of Santa Maria dei Servi, Bologna, Italy). Furthermore, the study of the painting combined with that of tempera paint mock-ups permitted to explore and define the environmental agents and internal factors causing the darkening, by proving that: (i) Ag-0 and moisture are key-factors for triggering the transformation of As2S3 to alpha-Ag2S and As-oxides; (ii) S2--ions arising from the degradation of As2S3 are the main responsible for the formation of alpha-Ag2S; (iii) light exposure strengthens the tendency of the paint components towards alteration. Based on our findings, we finally propose a degradation mechanism of As2S3/Ag-0-based tempera paints.
Keywords: A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 3.4
DOI: 10.1039/D1JA00271F
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“Non-invasive and non-destructive examination of artists’ pigments, paints and paintings by means of X-ray imaging methods”. Vanmeert F, De Meyer S, Gestels A, Clerici EA, Deleu N, Legrand S, Van Espen P, Van der Snickt G, Alfeld M, Dik J, Monico L, De Nolf W, Cotte M, Gonzalez V, Saverwyns S, Depuydt-Elbaum L, Janssens K page 317 (2022).
Abstract: Recent studies in which X-ray beams of (sub)micrometre to millimetre dimensions have been used for non-destructive analysis and characterization of pigments, minute paint samples and/or entire paintings from fifteenth to twentieth century artists are discussed. The overview presented encompasses the use of laboratory and synchrotron radiation-based instrumentation and deals with the use of several variants of X-ray fluorescence (XRF) as a method of elemental analysis and imaging as well as with the combined use with X-ray diffraction (XRD). Microscopic XRF (μ-XRF) is a variant of the XRF method able to visualize the elemental distribution of key elements, mostly metals, on the scale from 1 μm to 100 μm present inside multi-layered micro samples taken from paintings. In the context of the characterization of artists’ pigments subjected to natural degradation, in many cases the use of methods limited to elemental analysis or imaging does not suffice to elucidate the chemical transformations that have taken place. However, at synchrotron facilities, combinations of μ-XRF with related methods such as μ-XAS (microscopic X-ray absorption spectroscopy) and μ-XRD have proven themselves to be very suitable for such studies. Since microscopic investigation of a relatively limited number of minute paint samples may not yield representative information about the complete artefact they were taken from, several methods for macroscopic, non-invasive imaging have recently been developed. Combined macroscopic XRF/XRD scanning is able to provide a fairly complete overview of the inorganic pigments employed to create a work of art, to answer questions about ongoing degradation phenomena and about its authenticity. As such these newly developed non-invasive and highly specific imaging methods are of interest for many cultural heritage stakeholders.
Keywords: H1 Book chapter; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
DOI: 10.1007/978-3-030-86865-9_11
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“Reviving degraded colors of yellow flowers in 17th century still life paintings with macro- and microscale chemical imaging”. De Keyser N, Broers F, Vanmeert F, De Meyer S, Gabrieli F, Hermens E, van der Snickt G, Janssens K, Keune K, Science Advances 8, 1 (2022). http://doi.org/10.1126/SCIADV.ABN6344
Abstract: Over time, artist pigments are prone to degradation, which can decrease the readability of the artwork or notably change the artist's intention. In this article, the visual implication of secondary degradation products in a degraded yellow rose in a still life painting by A. Mignon is discussed as a case study. A multimodal combination of chemical and optical imaging techniques, including noninvasive macroscopic x-ray powder diffraction (MA-XRPD) and macroscopic x-ray fluorescence imaging, allowed us to gain a 3D understanding of the transformation of the original intended appearance of the rose into its current degraded state. MA-XRPD enabled us to precisely correlate in situ formed products with what is optically visible on the surface and demonstrated that the precipitated lead arsenates and arsenolite from the yellow pigment orpiment and the light-induced fading of an organic yellow lake irreversibly changed the artist's intentional light-shadow modeling.
Keywords: A1 Journal article; Engineering sciences. Technology; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 13.6
DOI: 10.1126/SCIADV.ABN6344
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“SEM-EDX hyperspectral data analysis for the study of soil aggregates”. Allegretta I, Legrand S, Alfeld M, Gattullo CE, Porfido C, Spagnuolo M, Janssens K, Terzano R, Geoderma: an international journal of soil science 406 (2022). http://doi.org/10.1016/J.GEODERMA.2021.115540
Abstract: Scanning electron microscopy coupled with microanalysis (SEM-EDX) is an important analytical tool for the morphological and chemical characterization of different types of materials. In many applications, SEM-EDX elemental maps are usually used and processed as images, thus flattening and reducing the spectroscopic information contained in EDX hyperspectral data cubes. The exploitation of the full hyperspectral dataset could be indeed very useful for the study of complex matrices like soil. In order to maximize the information attainable by SEM-EDX data cubes analysis, the software package “Datamuncher Gamma” was implemented and applied to study soil aggregates. By using this approach, different phases (silicates, aluminosilicates, Ca-carbonates, Ca-phosphates, organic matter, iron oxides) inside soil aggregates were successfully identified and segmented. The advantages of this method over the common ROI imaging approach are presented. Finally, this method was used to compare different aggregates in a Cr-polluted soil and understand their possible pedological history. The present method can be used for the analysis of every type of SEM-EDX data cubes, allowing its application to different types of samples and fields of study.
Keywords: A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 6.1
DOI: 10.1016/J.GEODERMA.2021.115540
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“Synchrotron XRF analysis identifies cerium accumulation colocalized with pharyngeal deformities in CeO₂, NP-exposed caenorhabditis elegans”. Rossbach LM, Brede DA, Nuyts G, Cagno S, Olsson RMS, Oughton DH, Falkenberg G, Janssens K, Lind OC, Environmental science and technology 56, 5081 (2022). http://doi.org/10.1021/ACS.EST.1C08509
Abstract: A combination of synchrotron radiation-based elementalimaging, in vivo redox status analysis, histology, and toxic responses was usedto investigate the uptake, biodistribution, and adverse effects of Cenanoparticles (CeO2NP; 10 nm; 0.5-34.96 mg Ce L-1) or Ce(NO3)3(2.3-26 mg Ce L-1)inCaenorhabditis elegans. Elemental mapping of theexposed nematodes revealed Ce uptake in the alimentary canal prior todepuration. Retention of CeO2NPs was low compared to that of Ce(NO3)3in depurated individuals. X-rayfluorescence (XRF) mapping showed that Cetranslocation was confined to the pharyngeal valve and foregut. Ce(NO3)3exposure significantly decreased growth, fertility, and reproduction, causedslightly reduced fecundity. XRF mapping and histological analysis revealedsevere tissue deformities colocalized with retained Ce surrounding thepharyngeal valve. Both forms of Ce activated the sod-1 antioxidant defense,particularly in the pharynx, whereas no significant effects on the cellular redox balance were identified. The CeO2NP-induceddeformities did not appear to impair the pharyngeal function or feeding ability as growth effects were restricted to Ce(NO3)3exposure. The results demonstrate the utility of integrated submicron-resolution SR-based XRF elemental mapping of tissue-specificdistribution and adverse effect analysis to obtain robust toxicological evaluations of metal-containing contaminants.
Keywords: A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 11.4
DOI: 10.1021/ACS.EST.1C08509
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“The dark halo technique in the oeuvre of Michael Sweerts and other Flemish and Dutch baroque painters. A 17th c. empirical solution to mitigate the optical 'simultaneous contrast' effect?”.Derks K, van der Snickt G, Legrand S, van der Stighelen K, Janssens K, Heritage science 10, 5 (2022). http://doi.org/10.1186/S40494-021-00634-W
Abstract: Although the topic is rarely addressed in literature, a significant number of baroque paintings exhibit dark, halo-like shapes around the contours of the dramatis personae. Close examination of both finished and unfinished works suggests that this intriguing feature was a practical tool that helped the artist in the early painting stages. When applying the final brushwork, the halo lost its function, with some artists undertaking efforts to hide it. Although their visibility might not have been intended by the artists, today this dark paint beneath the surface is partially visible through the upper paint layers. Moreover, the disclosure of many halos using infrared photography (IRP), infrared reflectography (IRR) and macro X-ray fluorescence imaging (MA-XRF), additional to those that can be observed visually, suggests that this was a common and established element of 17th-century painting practice in Western Europe. Building on an existing hypothesis, we argue that halos can be considered as a solution to an optical problem that arose when baroque painters reversed the traditional, 15th- and 16th-century painting sequence of working from background to foreground. Instead, they started with the dominant parts of a composition, such as the face of a sitter. In that case, a temporary halo can provide the essential tonal reference to anticipate the chromatic impact of the final dark colored background on the adjacent delicate carnations. In particular, we attempt to clarify the prevalence of dark halos as a response to optical effects such as 'simultaneous contrast' and 'the crispening effect', described in literature only centuries later. As such, the recently termed 'ring condition' can be seen as the present-day equivalent of the 'halo solution' that was seemingly empirically or intuitively developed by 17th-century artists. Modern studies in visual perception proves that by laying a black ring around a target color, the optical impact of a surrounding color can be efficiently neutralized. Finally, by delving into works by Michael Sweerts, it becomes clear that resourceful artists might have adapted the halo technique and the underlying principles to their individual challenges, such as dealing with differently colored grounds.
Keywords: A1 Journal article; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 2.5
DOI: 10.1186/S40494-021-00634-W
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“The “Historical Materials BAG&rdquo, : a new facilitated access to synchrotron X-ray diffraction analyses for cultural heritage materials at the European Synchrotron Radiation Facility”. Cotte M, Gonzalez V, Vanmeert F, Monico L, Dejoie C, Burghammer M, Huder L, de Nolf W, Fisher S, Fazlic I, Chauffeton C, Wallez G, Jimenez N, Albert-Tortosa F, Salvado N, Possenti E, Colombo C, Ghirardello M, Comelli D, Avranovich Clerici E, Vivani R, Romani A, Costantino C, Janssens K, Taniguchi Y, McCarthy J, Reichert H, Susini J, Molecules: a journal of synthetic chemistry and natural product chemistry 27, 1997 (2022). http://doi.org/10.3390/MOLECULES27061997
Abstract: The European Synchrotron Radiation Facility (ESRF) has recently commissioned the new Extremely Brilliant Source (EBS). The gain in brightness as well as the continuous development of beamline instruments boosts the beamline performances, in particular in terms of accelerated data acquisition. This has motivated the development of new access modes as an alternative to standard proposals for access to beamtime, in particular via the “block allocation group” (BAG) mode. Here, we present the recently implemented “historical materials BAG”: a community proposal giving to 10 European institutes the opportunity for guaranteed beamtime at two X-ray powder diffraction (XRPD) beamlines-ID13, for 2D high lateral resolution XRPD mapping, and ID22 for high angular resolution XRPD bulk analyses-with a particular focus on applications to cultural heritage. The capabilities offered by these instruments, the specific hardware and software developments to facilitate and speed-up data acquisition and data processing are detailed, and the first results from this new access are illustrated with recent applications to pigments, paintings, ceramics and wood.
Keywords: A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 4.6
DOI: 10.3390/MOLECULES27061997
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