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	Author	Rossbach, L.M.; Brede, D.A.; Nuyts, G.; Cagno, S.; Olsson, R.M.S.; Oughton, D.H.; Falkenberg, G.; Janssens, K.; Lind, O.C.
	Title	Synchrotron XRF analysis identifies cerium accumulation colocalized with pharyngeal deformities in CeO₂ NP-exposed caenorhabditis elegans			Type	A1 Journal article
	Year	2022	Publication	Environmental science and technology	Abbreviated Journal	Environ Sci Technol
	Volume	56	Issue	8	Pages	5081-5089
	Keywords	A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000793137500039	Publication Date	2022-04-04
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0013-936x; 1520-5851	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	11.4	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 11.4
	Call Number	UA @ admin @ c:irua:188662			Serial	7216
Permanent link to this record



	Author	Derks, K.; van der Snickt, G.; Legrand, S.; van der Stighelen, K.; Janssens, K.
	Title	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?			Type	A1 Journal article
	Year	2022	Publication	Heritage science	Abbreviated Journal
	Volume	10	Issue	1	Pages	5
	Keywords	A1 Journal article; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000739965700001	Publication Date	2022-01-07
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2050-7445	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.5	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 2.5
	Call Number	UA @ admin @ c:irua:185458			Serial	7217
Permanent link to this record



	Author	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.
	Title	The “Historical Materials BAG” : a new facilitated access to synchrotron X-ray diffraction analyses for cultural heritage materials at the European Synchrotron Radiation Facility			Type	A1 Journal article
	Year	2022	Publication	Molecules: a journal of synthetic chemistry and natural product chemistry	Abbreviated Journal	Molecules
	Volume	27	Issue	6	Pages	1997-21
	Keywords	A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000776369800001	Publication Date	2022-03-21
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1420-3049	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	4.6	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 4.6
	Call Number	UA @ admin @ c:irua:188053			Serial	7218
Permanent link to this record



	Author	Gonzalez, V.; Fazlic, I.; Cotte, M.; Vanmeert, F.; Gestels, A.; De Meyer, S.; Broers, F.; Hermans, J.; van Loon, A.; Janssens, K.; Noble, P.; Keune, K.
	Title	Lead(II) formate in Rembrandt's Night Watch : detection and distribution from the macro- to the micro-scale			Type	A1 Journal article
	Year	2023	Publication	Angewandte Chemie: international edition in English	Abbreviated Journal
	Volume		Issue		Pages	1-9
	Keywords	A1 Journal article; Art; Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract	The Night Watch, painted in 1642 and on view in the Rijksmuseum in Amsterdam, is considered Rembrandt's most famous work. X-ray powder diffraction (XRPD) mapping at multiple length scales revealed the unusual presence of lead(II) formate, Pb(HCOO)(2), in several areas of the painting. Until now, this compound was never reported in historical oil paints. In order to get insights into this phenomenon, one possible chemical pathway was explored thanks to the preparation and micro-analysis of model oil paint media prepared by heating linseed oil and lead(II) oxide (PbO) drier as described in 17(th) century recipes. Synchrotron radiation based micro-XRPD (SR-mu-XRPD) and infrared microscopy were combined to identify and map at the micro-scale various neo-formed lead-based compounds in these model samples. Both lead(II) formate and lead(II) formate hydroxide Pb(HCOO)(OH) were detected and mapped, providing new clues regarding the reactivity of lead driers in oil matrices in historical paintings.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000920584500001	Publication Date	2023-01-02
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1433-7851; 0570-0833	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	16.6	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 16.6; 2023 IF: 11.994
	Call Number	UA @ admin @ c:irua:194279			Serial	7318
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	Author	Hillen, M.; Sels, S.; Ribbens, B.; Verspeek, S.; Janssens, K.; Van der Snickt, G.; Steenackers, G.
	Title	Qualitative Comparison of Lock-in Thermography (LIT) and Pulse Phase Thermography (PPT) in Mid-Wave and Long-Wave Infrared for the Inspection of Paintings			Type	A1 Journal article
	Year	2023	Publication	Applied Sciences	Abbreviated Journal	Appl Sci-Basel
	Volume	13	Issue	7	Pages	1-13
	Keywords	A1 Journal article; Engineering sciences. Technology; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract	When studying paintings with active infrared thermography (IRT), minimizing the temperature fluctuations and thermal shock during a measurement becomes important. Under these conditions, it might be beneficial to use lock-in thermography instead of the conventionally used pulse thermography (PT). This study compared the observations made with lock-in thermography (LIT) and pulse phase thermography (PPT) with halogen light excitation. Three distinctly different paintings were examined. The LIT measurements caused smaller temperature fluctuations and, overall, the phase images appeared to have a higher contrast and less noise. However, in the PPT phase images, the upper paint layer was less visible, an aspect which is of particular interest when trying to observe subsurface defects or the structure of the support. The influence of the spectral range of the cameras on the results was also investigated. All measurements were taken with a mid-wave infrared (MWIR) and long wave infrared (LWIR) camera. The results show that there is a significant number of direct reflection artifacts, caused by the use of the halogen light sources when using the MWIR camera. Adding a long-pass filter to the MWIR camera eliminated most of these artifacts. All results are presented in a side-by-side comparison.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000972133900001	Publication Date	2023-03-24
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2076-3417	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.7	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 2.7; 2023 IF: 1.679
	Call Number	UA @ admin @ c:irua:194898			Serial	7333
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	Author	De Kerf, T.; Gestels, A.; Janssens, K.; Scheunders, P.; Steenackers, G.; Vanlanduit, S.
	Title	Quantitative detection of corrosion minerals in carbon steel using shortwave infrared hyperspectral imaging			Type	A1 Journal article
	Year	2022	Publication	RSC advances	Abbreviated Journal	Rsc Adv
	Volume	12	Issue	50	Pages	32775-32783
	Keywords	A1 Journal article; Engineering sciences. Technology; Vision lab; Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract	This study presents a novel method for the detection and quantification of atmospheric corrosion products on carbon steel. Using hyperspectral imaging (HSI) in the short-wave infrared range (SWIR) (900-1700 nm), we are able to identify the most common corrosion minerals such as: alpha-FeO(OH) (goethite), gamma-FeO(OH) (lepidocrocite), and gamma-Fe2O3 (maghemite). Six carbon steel samples were artificially corroded in a salt spray chamber, each sample with a different duration (between 1 h and 120 hours). These samples were analysed by scanning X-ray diffraction (XRD) and also using a SWIR HSI system. The XRD data is used as baseline data. A random forest regression algorithm is used for training on the combined XRD and HSI data set. Using the trained model, we can predict the abundance map based on the HSI images alone. Several image correlation metrics are used to assess the similarity between the original XRD images and the HSI images. The overall abundance is also calculated and compared for XRD and HSI images. The analysis results show that we are able to obtain visually similar images, with error rates ranging from 3.27 to 13.37%. This suggests that hyperspectral imaging could be a viable tool for the study of corrosion minerals.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000885554600001	Publication Date	2022-11-15
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2046-2069	ISBN		Additional Links	UA library record; WoS full record
	Impact Factor	3.9	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 3.9
	Call Number	UA @ admin @ c:irua:192085			Serial	7334
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	Author	Byrnes, I.; Rossbach, L.M.; Jaroszewicz, J.; Grolimund, D.; Sanchez, D.F.; Gomez-Gonzalez, M.A.; Nuyts, G.; Reinoso-Maset, E.; Janssens, K.; Salbu, B.; Brede, D.A.; Lind, O.C.
	Title	Synchrotron XRF and histological analyses identify damage to digestive tract of uranium NP-exposed Daphnia magna			Type	A1 Journal article
	Year	2023	Publication	Environmental science and technology	Abbreviated Journal
	Volume	57	Issue	2	Pages	1071-1079
	Keywords	A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract	Micro-and nanoscopic X-ray techniques were used to investigate the relationship between uranium (U) tissue distributions and adverse effects to the digestive tract of aquatic model organism Daphnia magna following uranium nanoparticle (UNP) exposure. X-ray absorption computed tomography measure-ments of intact daphnids exposed to sublethal concentrations of UNPs or a U reference solution (URef) showed adverse morphological changes to the midgut and the hepatic ceca. Histological analyses of exposed organisms revealed a high proportion of abnormal and irregularly shaped intestinal epithelial cells. Disruption of the hepatic ceca and midgut epithelial tissues implied digestive functions and intestinal barriers were compro-mised. Synchrotron-based micro X-ray fluorescence (XRF) elemental mapping identified U co-localized with morphological changes, with substantial accumulation of U in the lumen as well as in the epithelial tissues. Utilizing high-resolution nano-XRF, 400-1000 nm sized U particulates could be identified throughout the midgut and within hepatic ceca cells, coinciding with tissue damages. The results highlight disruption of intestinal function as an important mode of action of acute U toxicity in D. magna and that midgut epithelial cells as well as the hepatic ceca are key target organs.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000910915100001	Publication Date	2023-01-04
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0013-936x; 1520-5851	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	11.4	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 11.4; 2023 IF: 6.198
	Call Number	UA @ admin @ c:irua:193478			Serial	7342
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	Author	Alvarez-Martin, A.; Newsome, G.A.; Janssens, K.
	Title	High-resolution mass spectrometry and nontraditional mass defect analysis of brominated historical pigments			Type	A1 Journal article
	Year	2021	Publication	Analytical Chemistry	Abbreviated Journal	Anal Chem
	Volume	93	Issue	44	Pages	14851-14858
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract	The implementation of high-resolution mass spectrometry systems offers new possibilities for the analysis of complex art samples such as historical oil paintings. However, these multicomponent systems generate large and complex data sets that require advanced visualization tools to aid interpretation, especially when no chromatographic separation is performed. In the context of this research, it was crucial to propose a data analysis tool to identify the products generated during the synthesis, drying, and aging of historical pigments. This study reports for the first time a nontraditional mass defect analysis of oil paint samples containing a fugitive brominated-organic pigment, eosin or geranium lake, by using direct infusion electrospray ionization in combination with a high-resolution Orbitrap mass spectrometer. The use of nontraditional Kendrick mass defect plots is presented in this study as a processing and visualization tool to recognize brominated species based on their specific mass defect and isotope pattern. The results demonstrate that this approach could provide valuable molecular compositional information on the degradation pathways of this pigment. We anticipate that mass defect analysis will become highly relevant in future degradation studies of many more historical organic pigments.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000718171600037	Publication Date	2021-10-29
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700; 5206-882x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 6.32
	Call Number	UA @ admin @ c:irua:182347			Serial	8038
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	Author	Mudronja, D.; Vanmeert, F.; Fazinic, S.; Janssens, K.; Tibljas, D.; Desnica, V.
	Title	Protection of stone monuments using a brushing treatment with ammonium oxalate			Type	A1 Journal article
	Year	2021	Publication	Coatings	Abbreviated Journal	Coatings
	Volume	11	Issue	4	Pages	379
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Stone monuments and buildings are susceptible to weathering. Carbonate-based stones are especially vulnerable in acidic environments, whereas magmatic acidic stones are more susceptible to chemical weathering in basic environments. To slow down surface corrosion of limestone and marble artworks/buildings, protective coatings which inhibit calcite dissolution have been proposed. In this work, samples from two stone types with different porosity were treated with ammonium oxalate (AmOx) to create a protective layer of calcium oxalate (CaOx) using the previously developed brushing method. Two different synchrotron microscopy experiments were performed to determine its protective capability. X-ray powder diffraction (SR-mu-XRPD) in transmission geometry allowed visualization of the distributions of calcium carbonate and oxalates along the sample depths. In a second step, X-ray fluorescence (SR-mu-XRF) was used to check the efficiency/integrity of the protective surface coating layer. This was done by measuring the sulfur distribution on the stone surface after exposing the protected stones to sulfuric acid. XRPD showed the formation of a protective oxalate layer with a thickness of 5-15 mu m on the less porous stone, while a 20-30 mu m thick layer formed on the more porous stone. The XRF study showed that the optimal treatment time depends on the stone porosity. Increasing the treatment time from 1 to 3 h resulted in a decreased efficiency of the protective layer for the low porosity stone. We assume that this is due to the formation of vertical channels (cracks) in the protective layer.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000642940900001	Publication Date	2021-03-25
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2079-6412	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.175	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 2.175
	Call Number	UA @ admin @ c:irua:178271			Serial	8428
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	Author	Al-Emam, E.; Beltran, V.; De Meyer, S.; Nuyts, G.; Wetemans, V.; De Wael, K.; Caen, J.; Janssens, K.
	Title	Removal of a past varnish treatment from a 19th-century Belgian wall painting by means of a solvent-loaded double network hydrogel			Type	A1 Journal article
	Year	2021	Publication	Polymers	Abbreviated Journal	Polymers-Basel
	Volume	13	Issue	16	Pages	2651-20
	Keywords	A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES); Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab); Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract	Polymeric materials have been used by painting conservator-restorers as consolidants and/or varnishes for wall paintings. The application of these materials is carried out when confronting loose paint layers or as a protective coating. However, these materials deteriorate and cause physiochemical alterations to the treated surface. In the past, the monumental neo-gothic wall painting 'The Last Judgment' in the chapel of Sint-Jan Berchmanscollege in Antwerp, Belgium was treated with a synthetic polymeric material. This varnish deteriorated significantly and turned brown, obscuring the paint layers. Given also that the varnish was applied to some parts of the wall painting and did not cover the entire surface, it was necessary to remove it in order to restore the original appearance of the wall painting. Previous attempts carried out by conservator-restorers made use of traditional cleaning methods, which led to damage of the fragile paint layers. Therefore, gel cleaning was proposed as a less invasive and more controllable method for gently softening and removing the varnish. The work started by identifying the paint stratigraphy and the deteriorated varnish via optical microscopy (OM), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. A polyvinyl alcohol-borax/agarose (PVA-B/AG) hydrogel loaded with a number of solvents/solvent mixtures was employed in a series of tests to select the most suitable hydrogel composite. By means of the hydrogel composite loaded with 10% propylene carbonate, it was possible to safely remove the brown varnish layer. The results were verified by visual examinations (under visible light 'VIS' and ultraviolet light 'UV') as well as OM and FTIR spectroscopy.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000690248000001	Publication Date	2021-08-10
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2073-4360	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.364	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 3.364
	Call Number	UA @ admin @ c:irua:181567			Serial	8470
Permanent link to this record



	Author	Schalm, O.; Nuyts, G.; Janssens, K.
	Title	Some critical observations about the degradation of glass : the formation of lamellae explained			Type	A1 Journal article
	Year	2021	Publication	Journal Of Non-Crystalline Solids	Abbreviated Journal	J Non-Cryst Solids
	Volume	569	Issue		Pages	120984
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	This study demonstrates that the mechanism responsible for the transformation of glass into a degradation layer is pH-dependent. In acid conditions, the transformed glass is homogeneous and brittle. In mild alkaline conditions, transformed glass is heterogeneous due to the presence of lamellae composed of silica nanoparticles and the occurrence of Ca-rich inclusions. The fundamental difference between acid and alkaline conditions cannot be explained by the currently accepted degradation mechanism based on ion exchange. To explain this critical observation, we propose a refined degradation mechanism based on existing knowledge that involves several inwardly moving reaction fronts. The fronts responsible for the transformation of the silicate network into amorphous silica are also responsible for the morphology of the transformed glass. We have identified the feedback mechanism that explains the formation of lamellae in alkaline conditions.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000674487200009	Publication Date	2021-06-20
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0022-3093	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.124	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 2.124
	Call Number	UA @ admin @ c:irua:179835			Serial	8551
Permanent link to this record



	Author	Al-Emam, E.; Motawea, A.G.; Caen, J.; Janssens, K.
	Title	Soot removal from ancient Egyptian complex painted surfaces using a double network gel : empirical tests on the ceiling of the sanctuary of Osiris in the temple of Seti I-Abydos			Type	A1 Journal article
	Year	2021	Publication	Heritage science	Abbreviated Journal
	Volume	9	Issue	1	Pages	1-10
	Keywords	A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
	Abstract	In this study, we evaluated the ease of removal of soot layers from ancient wall paintings by employing double network gels as a controllable and safe cleaning method. The ceiling of the temple of Seti I (Abydos, Egypt) is covered with thick layers of soot; this is especially the case in the sanctuary of Osiris. These layers may have been accumulated during the occupation of the temple by Christians, fleeing the Romans in the first centuries A.D. Soot particulates are one of the most common deposits to be removed during conservation-restoration activities of ancient Egyptian wall paintings. They usually mask the painted reliefs and reduce the permeability of the painted surface. A Polyvinyl alcohol-borax/agarose (PVA-B/AG) double network gel was selected for this task since its properties were expected to be compatible with the cleaning treatment requirements. The gel is characterized by its flexibility, permitting to take the shape of the reliefs, while also having self-healing properties, featuring shape stability and an appropriate capacity to retain liquid. The gel was loaded with several cleaning reagents that proved to be effective for soot removal. Soot removal tests were conducted with these gel composites. The cleaned surfaces were evaluated with the naked eye, a digital microscope, and color measurements in order to select the best gel composite. The gel composite, loaded with a solution of 5% ammonia, 0.3% ammonium carbonate, and 0.3% EDTA yielded the most satisfactory results and allowed to safely remove a crust of thick soot layers from the surface. Thus, during the final phase of the study, it was used successfully to clean a larger area of the ceiling.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000604977300001	Publication Date	2021-01-04
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2050-7445	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor		Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:174948			Serial	8557
Permanent link to this record



	Author	Byrnes, I.; Rossbach, L.M.; Brede, D.A.; Grolimund, D.; Sanchez, D.F.; Nuyts, G.; Cuba, V.; Reinoso-Maset, E.; Salbu, B.; Janssens, K.; Oughton, D.; Scheibener, S.; Teien, H.-C.; Lind, O.C.
	Title	Synchrotron-based X-ray fluorescence imaging elucidates uranium toxicokinetics in Daphnia magna			Type	A1 Journal article
	Year	2023	Publication	ACS nano	Abbreviated Journal
	Volume	17	Issue	6	Pages	5296-5305
	Keywords	A1 Journal article; Engineering sciences. Technology; Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract	A combination of synchrotron-based elemental anal-ysis and acute toxicity tests was used to investigate the biodistribution and adverse effects in Daphnia magna exposed to uranium nanoparticle (UNP, 3-5 nm) suspensions or to uranium reference (Uref) solutions. Speciation analysis revealed similar size distributions between exposures, and toxicity tests showed com-parable acute effects (UNP LC50: 402 mu g L-1 [336-484], Uref LC50: 268 mu g L-1 [229-315]). However, the uranium body burden was 3 -to 5-fold greater in UNP-exposed daphnids, and analysis of survival as a function of body burden revealed a similar to 5-fold higher specific toxicity from the Uref exposure. High-resolution X-ray fluorescence elemental maps of intact, whole daphnids from sublethal, acute exposures of both treatments revealed high uranium accumulation onto the gills (epipodites) as well as within the hepatic ceca and the intestinal lumen. Uranium uptake into the hemolymph circulatory system was inferred from signals observed in organs such as the heart and the maxillary gland. The substantial uptake in the maxillary gland and the associated nephridium suggests that these organs play a role in uranium removal from the hemolymph and subsequent excretion. Uranium was also observed associated with the embryos and the remnants of the chorion, suggesting uptake in the offspring. The identification of target organs and tissues is of major importance to the understanding of uranium and UNP toxicity and exposure characterization that should ultimately contribute to reducing uncertainties in related environmental impact and risk assessments.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000960129800001	Publication Date	2023-03-15
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1936-0851	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	17.1	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 17.1; 2023 IF: 13.942
	Call Number	UA @ admin @ c:irua:196061			Serial	8631
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	Author	Avranovich Clerici, E.; De Meyer, S.; Vanmeert, F.; Legrand, S.; Monico, L.; Miliani, C.; Janssens, K.
	Title	Multi-scale X-ray imaging of the pigment discoloration processes triggered by chlorine compounds in the Upper Basilica of Saint Francis of Assisi			Type	A1 Journal article
	Year	2023	Publication	Molecules: a journal of synthetic chemistry and natural product chemistry	Abbreviated Journal
	Volume	28	Issue	16	Pages	6106-6123
	Keywords	A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract	In this paper, the chromatic alteration of various types of paints, present on mural painting fragments derived from the vaults of The Upper Basilica of Saint Francis of Assisi in Italy (12th-13th century), is studied using synchrotron radiation. Six painted mural fragments, several square centimeters in size, were available for analysis, originating from the ceiling paintings attributed to Cimabue and Giotto; they correspond to originally white, blue/green, and brown/yellow/orange areas showing discoloration. As well as collecting macroscopic X-ray fluorescence and diffraction maps from the entire fragments in the laboratory and at the SOLEIL synchrotron, corresponding paint cross-sections were also analyzed using microscopic X-ray fluorescence and powder diffraction mapping at the PETRA-III synchrotron. Numerous secondary products were observed on the painted surfaces, such as (a) copper tri-hydroxychloride in green/blue areas; (b) corderoite and calomel in vermillion red/cinnabar-rich paints; (c) plattnerite and/or scrutinyite assumed to be oxidation products of (hydro)cerussite (2PbCO(3)center dot Pb(OH)(2)) in the white areas, and (d) the calcium oxalates whewellite and weddellite. An extensive presence of chlorinated metal salts points to the central role of chlorine-containing compounds during the degradation of the 800-year-old paint, leading to, among other things, the formation of the rare mineral cumengeite (21PbCl(2)center dot 20Cu(OH) (2) center dot 6H(2)O).
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	001056388600001	Publication Date	2023-08-17
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1420-3049	ISBN		Additional Links	UA library record; WoS full record
	Impact Factor	4.6	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 4.6; 2023 IF: 2.861
	Call Number	UA @ admin @ c:irua:199265			Serial	8902
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	Author	Monico, L.; d'Acapito, F.; Cotte, M.; Janssens, K.; Romani, A.; Ricci, G.; Miliani, C.; Cartechini, L.
	Title	Total electron yield (TEY) detection mode Cr K-edge XANES spectroscopy as a direct method to probe the composition of the surface of darkened chrome yellow (PbCr1-xSxO4) and potassium chromate paints			Type	A1 Journal article
	Year	2023	Publication	Nuclear instruments and methods in physics research: B: beam interactions with materials and atoms	Abbreviated Journal
	Volume	539	Issue		Pages	141-147
	Keywords	A1 Journal article; Engineering sciences. Technology; Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract	The darkening of chromate-pigments, including chrome yellows (PbCr1-xSxO4), is a surface phenomenon affecting late 19th-early 20th c. paintings, such as those by Van Gogh. Exploring analytical strategies that contribute to a deep understanding of darkening is therefore significant for the long-term conservation of unique masterpieces. Here, we examined the capabilities of Cr K-edge XANES spectroscopy collected at the same time in X-ray fluorescence yield (XFY) and total electron yield (TEY) detection modes to selectively study the surface composition of darkened oil paint mock-ups composed of chrome yellow (PbCr0.2S0.8O4) or potassium chromate. By discussing advantages and drawbacks in using XFY/TEY modes in relation to XFY & mu;-XANES analysis from sectioned samples, we aim at assessing if TEY-XANES spectroscopy: (i) is a selective surface method to determine the abundance of different Cr-species from paint fragments; (ii) can contribute to optimize the analytical strategy by limiting time consuming sample preparation procedures; (iii) can decrease the probability of radiation damage.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	001041485400001	Publication Date	2023-04-10
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0168-583x	ISBN		Additional Links	UA library record; WoS full record
	Impact Factor	1.3	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 1.3; 2023 IF: 1.109
	Call Number	UA @ admin @ c:irua:198427			Serial	8944
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	Author	Ortega Saez, N.; Arno, R.; Marchetti, A.; Cauberghs, S.; Janssens, K.; Van der Snickt, G.; Al-Emam, E.
	Title	Towards a novel strategy for soot removal from water-soluble materials : the synergetic effect of hydrogels and cyclomethicone on gelatine emulsion-based photographs			Type	A1 Journal article
	Year	2023	Publication	Heritage science	Abbreviated Journal
	Volume	11	Issue	1	Pages	78-17
	Keywords	A1 Journal article; Engineering sciences. Technology; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract	Gels are a popular cleaning method for paper conservators and a lot of research has been done concerning gel cleaning of paper objects over the last 15 years. Despite the close interconnection between the conservation fields of paper and photographic material, research on using gels for cleaning photographs is very scarce. However, gels can provide an excellent cleaning method for photographic material. Cleaning silver gelatine prints with aqueous solvents is very complex due to the hydrophilic properties and fragility of the gelatine layer which makes mechanical cleaning difficult. The properties of gels ensure better control over the flow and evaporation of the solvent, facilitating the cleaning process. This study is the first insight into the viability of using gellan gum gel and polyvinyl acetate-borax (PVAc-borax) gel to clean contaminants from the surface of silver gelatine photographs. It is based on self-made samples that were artificially aged and contaminated with soot. Water, ethanol (EtOH), and Kodak Photo-flo were studied as solvents to remove the soot from the silver gelatine-based prints. These solvents were loaded into the aforementioned gels and applied to the samples in two different methods. These gel cleaning methods were subsequently compared with traditional cleaning methods. In addition, the usage of cyclomethicone D4 as a protective mask for the gelatine layer was studied. Measuring methods used to evaluate the cleaning were visual comparison, microscopic observation, and densitometry. ATR-FTIR measurements were also conducted to investigate potential side-effects of the cleaning methods on the prints, such as unwanted chemical transformations or the presence of gel residues after the treatments. Most of the gel cleaning methods within this study proved to be inadequate, with the exception of the gellan gum gel loaded with 30% EtOH. It was used as a granulated gel applied mechanically on a print saturated with cyclomethicone (octamethylcyclotetrasiloxane D4). Cyclomethicone proved to be a very effective protective barrier for the water-sensitive gelatine layer with minimal reduction in cleaning effectiveness.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000970139500001	Publication Date	2023-04-18
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2050-7445	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.5	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 2.5; 2023 IF: NA
	Call Number	UA @ admin @ c:irua:196445			Serial	8945
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	Author	Broers, F.T.H.; Janssens, K.; Weker, J.N.; Webb, S.M.; Mehta, A.; Meirer, F.; Keune, K.
	Title	Two pathways for the degradation of orpiment pigment (As₂S₃) found in paintings			Type	A1 Journal article
	Year	2023	Publication	Journal of the American Chemical Society	Abbreviated Journal
	Volume	145	Issue	16	Pages	8847-8859
	Keywords	A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract	Paintings are complex objects containing many different chemical compounds that can react over time. The degradation of arsenic sulfide pigments causes optical changes in paintings. The main degradation product was thought to be white arsenolite (As2O3), but previous research also showed the abundant presence of As(V) species. In this study, we investigate the influence of the presence of a medium on the degradation mechanism of orpiment (As2S3) using synchrotron radiation (SR)-based tomographic transmission X-ray microscopy, SR-based micro-X-ray fluorescence, and Xray absorption near edge structure spectroscopy. Upon direct illumination of dry orpiment powder using UV-visible light, only the formation of As2O3 was observed. When As2S3 was surrounded by a medium and illuminated, As2O3 was only observed in the area directly exposed to light, while As(V) degradation species were found elsewhere in the medium. Without accelerated artificial light aging, As(V)(aq) species are formed and migrate throughout the medium within weeks after preparation. In both scenarios, the As(V) species form via intermediate As(III)(aq) species and the presence of a medium is necessary. As(V)(aq) species can react with available cations to form insoluble metal arsenates, which induces stress within the paint layers (leading to, e.g., cracks and delamination) or can lead to a visual change of the image of the painting.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000974346900001	Publication Date	2023-04-14
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0002-7863	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	15	Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: 15; 2023 IF: 13.858
	Call Number	UA @ admin @ c:irua:196762			Serial	8948
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