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“Non-thermal plasma accelerates astrocyte regrowth and neurite regeneration following physical trauma in vitro”. Katiyar KS, Lin A, Fridman A, Keating CE, Cullen DK, Miller V, Applied Sciences 9, 3747 (2019). http://doi.org/10.3390/APP9183747
Abstract: Non-thermal plasma (NTP), defined as a partially ionized gas, is an emerging technology with several biomedical applications, including tissue regeneration. In particular, NTP treatment has been shown to activate endogenous biological processes to promote cell regrowth, differentiation, and proliferation in multiple cell types. However, the effects of this therapy on nervous system regeneration have not yet been established. Accordingly, the current study explored the effects of a nanosecond-pulsed dielectric barrier discharge plasma on neural regeneration. Following mechanical trauma in vitro, plasma was applied either directly to (1) astrocytes alone, (2) neurons alone, or (3) neurons or astrocytes in a non-contact co-culture. Remarkably, we identified NTP treatment intensities that accelerated both neurite regeneration and astrocyte regrowth. In astrocyte cultures alone, an exposure of 20-90 mJ accelerated astrocyte re-growth up to three days post-injury, while neurons required lower treatment intensities (<= 20 mJ) to achieve sub-lethal outgrowth. Following injury to neurons in non-contact co-culture with astrocytes, 20 mJ exposure of plasma to only neurons or astrocytes resulted in increased neurite regeneration at three days post-treatment compared to the untreated, but no enhancement was observed when both cell types were treated. At day seven, although regeneration further increased, NTP did not elicit a significant increase from the control. However, plasma exposure at higher intensities was found to be injurious, underscoring the need to optimize exposure levels. These results suggest that growth-promoting physiological responses may be elicited via properly calibrated NTP treatment to neurons and/or astrocytes. This could be exploited to accelerate neurite re-growth and modulate neuron-astrocyte interactions, thereby hastening nervous system regeneration.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.679
Times cited: 2
DOI: 10.3390/APP9183747
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“Plasma medicine technologies”. Kaushik NK, Bekeschus S, Tanaka H, Lin A, Choi EH, Applied Sciences-Basel 11, 4584 (2021). http://doi.org/10.3390/APP11104584
Abstract: This Special Issue, entitled “Plasma Medicine Technologies”, covers the latest remarkable developments in the field of plasma bioscience and medicine. Plasma medicine is an interdisciplinary field that combines the principles of plasma physics, material science, bioscience, and medicine, towards the development of therapeutic strategies. A study on plasma medicine has yielded the development of new treatment opportunities in medical and dental sciences. An important aspect of this issue is the presentation of research underlying new therapeutic methods that are useful in medicine, dentistry, sterilization, and, in the current scenario, that challenge perspectives in biomedical sciences. This issue is focused on basic research on the characterization of the bioplasma sources applicable to living cells, especially to the human body, and fundamental research on the mutual interactions between bioplasma and organic–inorganic liquids, and bio or nanomaterials.
Keywords: Editorial; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.679
DOI: 10.3390/APP11104584
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“Coincidence Detection of EELS and EDX Spectral Events in the Electron Microscope”. Jannis D, Müller-Caspary K, Béché, A, Verbeeck J, Applied Sciences-Basel 11, 9058 (2021). http://doi.org/10.3390/app11199058
Abstract: Recent advances in the development of electron and X-ray detectors have opened up the possibility to detect single events from which its time of arrival can be determined with nanosecond resolution. This allows observing time correlations between electrons and X-rays in the transmission electron microscope. In this work, a novel setup is described which measures individual events using a silicon drift detector and digital pulse processor for the X-rays and a Timepix3 detector for the electrons. This setup enables recording time correlation between both event streams while at the same time preserving the complete conventional electron energy loss (EELS) and energy dispersive X-ray (EDX) signal. We show that the added coincidence information improves the sensitivity for detecting trace elements in a matrix as compared to conventional EELS and EDX. Furthermore, the method allows the determination of the collection efficiencies without the use of a reference sample and can subtract the background signal for EELS and EDX without any prior knowledge of the background shape and without pre-edge fitting region. We discuss limitations in time resolution arising due to specificities of the silicon drift detector and discuss ways to further improve this aspect.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.679
Times cited: 9
DOI: 10.3390/app11199058
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“A scanning electron microscopy study on hollow silica microspheres: defects and influences of the synthesis composition”. Liu S, Wei M, Sui X, Cheng X, Cool P, Van Tendeloo G, Journal of sol-gel science and technology 49, 373 (2009). http://doi.org/10.1007/s10971-008-1875-0
Abstract: Defects on hollow silica spheres synthesized in a tetraethylorthosilicate-octylamine-HCl-H2O system were recorded by scanning microscope. Based on the results, influences of synthesis composition on the formation of these defects are discussed. It is evidenced that products prepared with different octylamine-to-tetraethylorthosilicate ratios may have surface depressions, cracks and non-hollow microspheres. However, by changing water and acid additions, these defects could be reduced or eliminated. Generally, samples synthesized with a large octylamine addition commonly exhibit surface depressions. A small octylamine or a large water addition benefits the formation of solid silica microspheres among the product. Acid, although is not indispensable for the formation of hollow spheres, helps to eliminate or reduce depressions on the hollow shells. It is explained that the added acid gives rise to a relative localized fast hydrolysis versus condensation, facilitating an easy mobility of hydrolyzed silica species, and consequently the shell surface is smoothened.
Keywords: A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Electron microscopy for materials research (EMAT)
Impact Factor: 1.575
Times cited: 1
DOI: 10.1007/s10971-008-1875-0
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“Effect of high-frequency electromagnetic field on Te+-implanted (001) Si</tex>”. Kalitzova M, Vlakhov E, Marinov Y, Gesheva K, Ignatova VA, Lebedev O, Muntele C, Gijbels R, Vacuum: the international journal and abstracting service for vacuum science and technology 76, 325 (2004). http://doi.org/10.1016/j.vacuum.2004.07.055
Abstract: The analysis of high-frequency electromagnetic field (HFEMF) effects on the microstructure and electrical properties of Te+ implanted (0 0 1) Si is reported. Cross-sectional high-resolution transmission electron microscopy (XHRTEM) demonstrates the formation of Te nanoclusters (NCs) embedded in the Si layer amorphized by implantation (a-Si) at fluences greater than or equal to 1 x 10(16) cm(-2). Post-implantation treatment with 0.45 MHz HFEMF leads to enlargement of Te NCs, their diffusion and accumulation at the a-Si surface and formation of laterally connected extended tellurium structures above the percolation threshold, appearing at an ion fluence of 1 x 10(17) cm(-2). AC electrical conductivity measurements show nearly four orders of magnitude decrease of impedance resistivity in this case, which is in good agreement with the results of our structural studies. The results obtained are discussed in terms of the two-phase isotropic spinodal structure. (C) 2004 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.53
Times cited: 2
DOI: 10.1016/j.vacuum.2004.07.055
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“Multistep loading of titania nanoparticles in the mesopores of SBA-15 for enhanced photocatalytic activity”. de Witte K, Cool P, de Witte I, Ruys L, Rao J, Van Tendeloo G, Vansant EF, Journal of nanoscience and nanotechnology 7, 2511 (2007). http://doi.org/10.1166/jnn.2007.445
Keywords: A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Electron microscopy for materials research (EMAT)
Impact Factor: 1.483
Times cited: 13
DOI: 10.1166/jnn.2007.445
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“Nanoscale Characterization of Growth of Secondary Phases in Off-Stoichiometric CZTS Thin Films”. Vishwakarma M, Karakulina OM, Abakumov AM, Hadermann J, Mehta BR, Journal of nanoscience and nanotechnology 18, 1688 (2018). http://doi.org/10.1166/jnn.2018.14261
Abstract: The presence of secondary phases is one of the main issues that hinder the growth of pure kesterite Cu2ZnSnS4 (CZTS) based thin films with suitable electronic and junction properties for efficient solar cell devices. In this work, CZTS thin films with varied Zn and Sn content have been prepared by RF-power controlled co-sputtering deposition using Cu, ZnS and SnS targets and a subsequent sulphurization step. Detailed TEM investigations show that the film shows a layered structure with the majority of the top layer being the kesterite phase. Depending on the initial thin film composition, either about ~1 μm Cu-rich and Zn-poor kesterite or stoichiometric CZTS is formed as top layer. X-ray diffraction, Raman spectroscopy and transmission electron microscopy reveal the presence of Cu2−x S, ZnS and SnO2 minor secondary phases in the form of nanoinclusions or nanoparticles or intermediate layers.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 1.483
DOI: 10.1166/jnn.2018.14261
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“Electrochemical sensing of phenicol antibiotics at gold”. Pilehvar S, Dardenne F, Blust R, De Wael K, International journal of electrochemical science 7, 5000 (2012)
Abstract: Phenicols are an effective and a broad spectrum class of antibiotics which has lost favour due to their side effects on human health. A rapid and sensitive electrochemical detection system is developed for the simultaneous detection of chloramphenicol (CAP), thiamphenicol (TAP) and florfenicol (FF). The electrochemical behaviour of CAP in the presence of its derivatives was investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV). At a gold electrode, CAP gives rise to a sensitive cathodic peak at −0.68V (versus SCE) in a tris buffer solution (pH 7.6). This behavior gives us the opportunity to introduce a method for sensing CAP electrochemically in the presence of its derivatives. Calibration graphs were linear in the 2.5-7.4 μmol L-1 concentration range. Deviations from linearity were observed for higher concentrations and this was interpreted to be due to kinetic limitation caused by the saturation of CAP and its reduction products onto the gold electrode surface. A limit of detection of 1 μmol L-1 was found.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.469
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“The electrochemistry of a gelatin modified gold electrode”. De Wael K, Verstraete A, van Vlierberghe S, Dejonghe W, Dubruel P, Adriaens A, International journal of electrochemical science 6, 1810 (2011)
Abstract: This paper discusses the electrochemical behaviour of gelatin coated gold electrodes in physiological pH conditions in a potential window −1.5 till 1.0 V vs SCE by performing cyclic voltammetry. A comparison is made between gelatin A and gelatin B, which have respectively a positive and a negative net charge at physiological pH. The deposition of gelatin onto the gold surface is confirmed by means of attenuated total reflection-infrared (ATR-IR) spectroscopic analyses.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.469
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“Dynamics of nanoclustering in Te+ implanted Si after application of high frequency electromagnetic field and thermal annealing”. Kalitzova M, Lebedev OI, Zollo G, Gesheva K, Vlakhov E, Marinov Y, Ivanova T;, Applied physics A : materials science &, processing 91, 515 (2008). http://doi.org/10.1007/s00339-008-4441-2
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.455
DOI: 10.1007/s00339-008-4441-2
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“Formation of Mn304/C core-shell nanowires and a new MN-O phase by electron beam irradiation”. Du GH, Van Tendeloo G, Applied physics A : materials science &, processing 91, 393 (2008). http://doi.org/10.1007/s00339-008-4430-5
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.455
Times cited: 1
DOI: 10.1007/s00339-008-4430-5
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“Interpretation of TOF-SIMS depth profiles from ultrashallow high-k dielectric stacks assisted by hybrid collisional computer simulation”. Ignatova VA, Möller W, Conard T, Vandervorst W, Gijbels R, Applied physics A : materials science &, processing 81, 71 (2005). http://doi.org/10.1007/s00339-005-3239-8
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.455
Times cited: 4
DOI: 10.1007/s00339-005-3239-8
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“Measurement of the size of embedded metal clusters by mass spectrometry, transmission electron microscopy, and small-angle X-ray scattering”. Hendrich C, Favre L, Ievlev DN, Dobrynin AN, Bras W, Hörmann U, Piscopiello E, Van Tendeloo G, Lievens P, Temst K, Applied physics A : materials science &, processing 86, 533 (2007). http://doi.org/10.1007/s00339-006-3808-5
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.455
Times cited: 11
DOI: 10.1007/s00339-006-3808-5
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“A TEM study of nanoparticles in lustre glazes”. Fredrickx P, Helary D, Schryvers D, Darque-Ceretti E, Applied physics A : materials science &, processing 79, 283 (2004). http://doi.org/10.1007/s00339-004-2515-3
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.455
Times cited: 16
DOI: 10.1007/s00339-004-2515-3
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“The corrosion process of sterling silver exposed to a Na2S solution: monitoring and characterizing the complex surface evolution using a multi-analytical approach”. Schalm O, Crabbé, A, Storme P, Wiesinger R, Gambirasi A, Grieten E, Tack P, Bauters S, Kleber C, Favaro M, Schryvers D, Vincze L, Terryn H, Patelli A, Applied Physics A-Materials Science &, Processing 122, 903 (2016). http://doi.org/10.1007/s00339-016-0436-6
Abstract: Many historical ‘silver’ objects are composed of sterling silver, a silver alloy containing small amounts of copper. Besides the dramatic impact of copper on the corrosion process, the chemical composition of the corrosion layer evolves continuously. The evolution of the surface during the exposure to a Na2S solution was monitored by means of visual observation at macroscopic level, chemical analysis at microscopic level and analysis at the nanoscopic level. The corrosion process starts with the preferential oxidation of copper, forming mixtures of oxides and sulphides while voids are being created beneath the corrosion layer. Only at a later stage, the silver below the corrosion layer is consumed. This results in the formation of jalpaite and at a later stage of acanthite. The acanthite is found inside the corrosion layer at the boundaries of jalpaite grains and as individual grains between the jalpaite grains but also as a thin film on top of the corrosion layer. The corrosion process could be described as a sequence of 5 subsequent surface states with transitions between these states.
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Impact Factor: 1.455
Times cited: 9
DOI: 10.1007/s00339-016-0436-6
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“Analysis of micro computed tomography images, a look inside historic enamelled metal objects”. van der Linden V, Van de Casteele E, Thomas MS, de Vos A, Janssen E, Janssens K, Applied physics A : materials science &, processing 98, 385 (2010). http://doi.org/10.1007/S00339-009-5394-9
Abstract: In this study the usefulness of micro-Computed Tomography (µ-CT) for the in-depth analysis of enamelled metal objects was tested. Usually investigations of enamelled metal artefacts are restricted to non-destructive surface analysis or analysis of cross sections after destructive sampling. Radiography, a commonly used technique in the field of cultural heritage studies, is limited to providing two-dimensional information about a three-dimensional object (Lang and Middleton, Radiography of Cultural Material, pp. 6061, Elsevier-Butterworth-Heinemann, Amsterdam-Stoneham-London, 2005). Obtaining virtual slices and information about the internal structure of these objects was made possible by CT analysis. With this technique the underlying metal work was studied without removing the decorative enamel layer. Moreover visible defects such as cracks were measured in both width and depth and as of yet invisible defects and weaker areas are visualised. All these features are of great interest to restorers and conservators as they allow a view inside these objects without so much as touching them.
Keywords: A1 Journal article; Vision lab; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.455
Times cited: 3
DOI: 10.1007/S00339-009-5394-9
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“Cultural heritage and archaeology materials studied by synchrotron spectroscopy and imaging”. Bertrand L, Robinet L, Thoury M, Janssens K, Cohen SX, Schöder S, Applied physics A : materials science &, processing 106, 377 (2012). http://doi.org/10.1007/S00339-011-6686-4
Abstract: The use of synchrotron radiation techniques to study cultural heritage and archaeological materials has undergone a steep increase over the past 10-15 years. The range of materials studied is very broad and encompasses painting materials, stone, glass, ceramics, metals, cellulosic and wooden materials, and a cluster of organic-based materials, in phase with the diversity observed at archaeological sites, museums, historical buildings, etc. Main areas of investigation are: (1) the study of the alteration and corrosion processes, for which the unique non-destructive speciation capabilities of X-ray absorption have proved very beneficial, (2) the understanding of the technologies and identification of the raw materials used to produce archaeological artefacts and art objects and, to a lesser extent, (3) the investigation of current or novel stabilisation, conservation and restoration practices. In terms of the synchrotron methods used, the main focus so far has been on X-ray techniques, primarily X-ray fluorescence, absorption and diffraction, and Fourier-transform infrared spectroscopy. We review here the use of these techniques from recent works published in the field demonstrating the breadth of applications and future potential offered by third generation synchrotron techniques. New developments in imaging and advanced spectroscopy, included in the UV/visible and IR ranges, could even broaden the variety of materials studied, in particular by fostering more studies on organic and complex organic-inorganic mixtures, while new support activities at synchrotron facilities might facilitate transfer of knowledge between synchrotron specialists and users from archaeology and cultural heritage sciences.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.455
Times cited: 55
DOI: 10.1007/S00339-011-6686-4
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“Efficiency of applying ammonium oxalate for protection of monumental limestone by poultice, immersion and brushing methods”. Mudronja D, Vanmeert F, Hellemans K, Fazinic S, Janssens K, Tibljas D, Rogosic M, Jakovljevic S, Applied physics A : materials science &, processing 111, 109 (2013). http://doi.org/10.1007/S00339-012-7365-9
Abstract: Samples of cretaceous limestone have been treated with three application methods (poultice, immersion and brushing) using different concentrations of ammonium oxalate solution (AmOx) and varying treatment time in order to test the efficiency of surface and in-depth formation of a protective layer of calcium oxalate (CaOx). Synchrotron-based microanalytical techniques (SR-mu XRD with 12.5 mu mx7.5 mu m (HxV) probe size, SR-mu FTIR with 10 mu mx10 mu m and 8 mu mx20 mu m probe sizes) and laboratory mu FTIR, XRD and SEM have been employed for analysis of the treated samples. Synchrotron-based techniques showed variations in the CaOx distribution along the surface on a micrometer scale. All treatments resulted in the development of a CaOx layer with a maximum thickness of approximately 40 mu m. Application by the brushing method with 10 1-min applications with 5-min breaks during one hour showed a development of the calcium oxalate layer equivalent to the poultice treatment taking 10 h. This treatment could be preferred for large marble or limestone surfaces where poultice usage is economically not feasible.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.455
Times cited: 13
DOI: 10.1007/S00339-012-7365-9
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“FTIR techniques applied to the detection of gelatine in paper artifacts: from macroscopic to microscopic approach”. Rouchon V, Pellizzi E, Janssens K, Applied physics A : materials science &, processing 100, 663 (2010). http://doi.org/10.1007/S00339-010-5649-5
Abstract: In order to render paper hydrophobic for ink and thus adequate for writing, gelatine has been largely used. To this day, it is still employed in conservation workshops as an adhesive or a sizing agent, for instance, during the treatment of iron gall ink manuscripts. Various types and concentrations of gelatine are recommended, depending on the desired effect, but little information is available regarding to the physical distribution of gelatine in the paper. This aspect is however determinant for a better control of conservation treatments. In this work, we investigate the possibilities offered by FTIR microscopy for the measurement of the gelatine distribution in paper. Laboratory papers were preliminary treated with different types of gelatine and then embedded in a resin and cut in thin slices. Mapping techniques enable to compare the penetration of different types of gelatine in a semiquantitative way. The performance of conventional laboratory equipment and synchrotron radiation experimental setup are discussed.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.455
Times cited: 12
DOI: 10.1007/S00339-010-5649-5
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“μ-XRF/μ-RS vs. SR μ-XRD for pigment identification in illuminated manuscripts”. van der Snickt G, de Nolf W, Vekemans B, Janssens K, Applied physics A : materials science &, processing 92, 59 (2008). http://doi.org/10.1007/S00339-008-4447-9
Abstract: For the non-destructive identification of pigments and colorants in works of art, in archaeological and in forensic materials, a wide range of analytical techniques can be used. Bearing in mind that every method holds particular limitations, two complementary spectroscopic techniques, namely confocal ì-Raman spectroscopy (ì-RS) and ì-X-ray fluorescence spectroscopy (ì-XRF), were joined in one instrument. The combined ì-XRF and ì-RS device, called PRAXIS unites both complementary techniques in one mobile setup, which allows ì- and in situ analysis. ì-XRF allows one to collect elemental and spatially-resolved information in a non-destructive way on major and minor constituents of a variety of materials. However, the main disadvantages of ì-XRF are the penetration depth of the X-rays and the fact that only elements and not specific molecular combinations of elements can be detected. As a result ì-XRF is often not specific enough to identify the pigments within complex mixtures. Confocal Raman microscopy (ì-RS) can offer a surplus as molecular information can be obtained from single pigment grains. However, in some cases the presence of a strong fluorescence background limits the applicability. In this paper, the concrete analytical possibilities of the combined PRAXIS device are evaluated by comparing the results on an illuminated sheet of parchment with the analytical information supplied by synchrotron radiation ì-X-ray diffraction (SR ì-XRD), a highly specific technique.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.455
Times cited: 56
DOI: 10.1007/S00339-008-4447-9
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“Monitoring the impact of the indoor air quality on silver cultural heritage objects using passive and continuous corrosion rate assessments”. 't Hart L, Storme P, Anaf W, Nuyts G, Vanmeert F, Dorriné, W, Janssens K, De Wael K, Schalm O, Applied physics A : materials science &, processing 122, 923 (2016). http://doi.org/10.1007/S00339-016-0456-2
Abstract: There is a long tradition in evaluating industrial atmospheres by measuring the corrosion rate of exposed metal coupons. The heritage community also uses this method, but the interpretation of the corrosion rate often lacks clarity due to the low corrosivity in indoor museum environments. This investigation explores the possibilities and drawbacks of different silver corrosion rate assessments. The corrosion rate is determined by three approaches: (1) chemical characterization of metal coupons using analytical techniques such as electrochemical measurements, SEM-EDX, XRD, and µ-Raman spectroscopy, (2) continuous corrosion monitoring methods based on electrical resistivity loss of a corroding nm-sized metal wire and weight gain of a corroding silver coated quartz crystal, and (3) characterization of the visual degradation of the metal coupons. This study confirms that subtle differences in corrosivity between locations inside a museum can be determined on condition that the same corrosion rate assessment is used. However, the impact of the coupon orientation with respect to the prevailing direction of air circulation can be substantially larger than the impact of the coupon location.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
Impact Factor: 1.455
Times cited: 3
DOI: 10.1007/S00339-016-0456-2
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“Neutron activation autoradiography and scanning macro-XRF of Rembrandt van Rijn's Susanna and the Elders (Gemaldegalerie Berlin) : a comparison of two methods for imaging of historical paintings with elemental contrast”. Alfeld M, Laurenze-Landsberg C, Denker A, Janssens K, Noble P, Applied physics A : materials science &, processing 119, 795 (2015). http://doi.org/10.1007/S00339-015-9081-8
Abstract: Imaging methods with elemental contrast are of great value for the investigation of historical paintings, as they allow for study of sub-surface layers that provide insight into a painting's creation process. Two of the most important methods are neutron activation autoradiography (NAAR) and scanning macro-XRF (MA-XRF). Given the differences between these methods in the fundamental physical phenomena exploited, a theoretical comparison of their capabilities is difficult and until now a critical comparison of their use on the same painting is missing. In this paper, we present a study of Rembrandt van Rijn's painting Susanna and the Elders from the Gemaldegalerie in Berlin employing both techniques. The painting features a considerable number of overpainted features and a wide range of pigments with different elemental tracers, including earth pigments (Mn/Fe), Azurite (Cu), lead white (Pb), vermilion (Hg) and smalt (Co, As). MA-XRF can detect all elements above Si (Z = 14), suffers from few spectral overlaps and can be performed in a few tens of hours in situ, i.e. in a museum. NAAR requires the stay of the painting at a research facility for several weeks, and inter-element interferences can be difficult to resolve. Also, only a limited number of elements contribute to the acquired autoradiographs, most notably Mn, Cu, As, Co, Hg and P. However, NAAR provides a higher lateral resolution and is less hindered by absorption in covering layers, which makes it the only method capable of visualizing P in lower paint layers.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.455
Times cited: 11
DOI: 10.1007/S00339-015-9081-8
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“Rembrandt's An Old Man in Military Costume: the underlying image re-examined”. Trentelman K, Janssens K, van der Snickt G, Szafran Y, Woollett AT, Dik J, Applied physics A : materials science &, processing 121, 801 (2015). http://doi.org/10.1007/S00339-015-9426-3
Abstract: The painting An Old Man in Military Costume in the J. Paul Getty Museum, by Rembrandt Harmensz van Rijn, was studied using two complementary, element-specific imaging techniques-neutron activation autoradiography (NAAR) and macro-X-ray fluorescence (MA-XRF) mapping-to reveal the second, hidden painting. NAAR provided a strong image of the face and cloak of the underlying figure, along with an indication of the chemical composition. The single-element distribution maps produced by MA-XRF mapping provided additional details into the shape of the underlying image and the composition of the pigments used. The underlying figure's face is richer in mercury, indicative of the pigment vermilion, than the face of the figure on the surface. Likewise, the cloak of the underlying figure is richer in copper than the surface figure though the identity of the copper-containing pigment cannot be determined from these data. The use of iron earth pigments, specifically Si-rich umbers, is indicated through the complementary information provided by the NAAR and MA-XRF maps. These data are used to create a false color digital reconstruction, yielding the most detailed representation of the underlying painting to date.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.455
Times cited: 22
DOI: 10.1007/S00339-015-9426-3
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“Scanning XRF investigation of a Flower Still Life and its underlying composition from the collection of the Kröller-Muller Museum”. Alfeld M, van der Snickt G, Vanmeert F, Janssens K, Dik J, Appel K, van der Loeff L, Chavannes M, Meedendorp T, Hendriks E, Applied physics A : materials science &, processing 111, 165 (2013). http://doi.org/10.1007/S00339-012-7526-X
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.455
Times cited: 35
DOI: 10.1007/S00339-012-7526-X
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“Visualizing the 17th century underpainting in Portrait of an Old Man by Rembrandt van Rijn using synchrotron-based scanning macro-XRF”. Alfeld M, Siddons DP, Janssens K, Dik J, Woll A, Kirkham R, van de Wetering E, Applied physics A : materials science &, processing 111, 157 (2013). http://doi.org/10.1007/S00339-012-7490-5
Abstract: In 17th century Old Master Paintings, the underpainting generally refers to the first sketch of a composition. The underpainting is applied to a prepared ground using a monochrome, brown oil paint to roughly indicate light, shade and contours. So far, methods to visualize the underpainting-other than in localized cross-sections-have been very limited. Neither infrared reflectography nor neutron induced autoradiography have proven to be practical, adequate visualization tools. Thus, although of fundamental interest in the understanding of a painting's genesis, the underpainting has virtually escaped all imaging efforts. In this contribution we will show that 17th century underpainting may consist of a highly heterogeneous mixture of pigments, including copper pigments. We suggest that this brown pigment mixture is actually the recycled left-over of a palette scraping. With copper as the heaviest exclusive elemental component, we will hence show in a case study on a Portrait of an Old Man attributed to Rembrandt van Rijn how scanning macro-XRF can be used to efficiently visualize the underpainting below the surface painting and how this information can contribute to the discussion of the painting's authenticity.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.455
Times cited: 26
DOI: 10.1007/S00339-012-7490-5
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“Addition of yttrium into HfO2 films: microstructure and electrical properties”. Dubourdieu C, Rauwel E, Roussel H, Ducroquet F, Hollaender B, Rossell M, Van Tendeloo G, Lhostis S, Rushworth S, Journal of vacuum science and technology: A: vacuum surfaces and films 27, 503 (2009). http://doi.org/10.1116/1.3106627
Abstract: The cubic phase of HfO2 was stabilized by addition of yttrium in thin films grown on Si/SiO2 by metal-organic chemical vapor deposition. The cubic phase was obtained for contents of 6.5 at. % Y or higher at a temperature as low as 470 °C. The complete compositional range (from 1.5 to 99.5 at. % Y) was investigated. The crystalline structure of HfO2 was determined from x-ray diffraction, electron diffraction, and attenuated total-reflection infrared spectroscopy. For cubic films, the continuous increase in the lattice parameter indicates the formation of a solid-solution HfO2Y2O3. As shown by x-ray photoelectron spectroscopy, yttrium silicate is formed at the interface with silicon; the interfacial layer thickness increases with increasing yttrium content and increasing film thickness. The dependence of the intrinsic relative permittivity r as a function of Y content was determined. It exhibits a maximum of ~30 for ~8.8 at. % Y. The cubic phase is stable upon postdeposition high-temperature annealing at 900 °C under NH3.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.374
Times cited: 29
DOI: 10.1116/1.3106627
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“Crystalline structure of very hard tungsten carbide thin films obtained by reactive pulsed laser deposition”. Mihailescu IN, Gyorgy E, Marin G, Popescu M, Teodorescu VS, van Landuyt J, Grivas C, Hatziapostolou A, Journal of vacuum science and technology: A: vacuum surfaces and films 17, 249 (1999). http://doi.org/10.1116/1.581579
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.374
Times cited: 8
DOI: 10.1116/1.581579
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“Electromagnetic effects in high-frequency large-area capacitive discharges : a review”. Liu Y-X, Zhang Y-R, Bogaerts A, Wang Y-N, Journal of vacuum science and technology: A: vacuum surfaces and films 33, 020801 (2015). http://doi.org/10.1116/1.4907926
Abstract: In traditional capacitively coupled plasmas, the discharge can be described by an electrostatic model, in which the Poisson equation is employed to determine the electrostatic electric field. However, current plasma reactors are much larger and driven at a much higher frequency. If the excitation wavelength k in the plasma becomes comparable to the electrode radius, and the plasma skin depth d becomes comparable to the electrode spacing, the electromagnetic (EM) effects will become significant and compromise the plasma uniformity. In this regime, capacitive discharges have to be described by an EM model, i.e., the full set of Maxwells equations should be solved to address the EM effects. This paper gives an overview of the theory, simulation and experiments that have recently been carried out to understand these effects, which cause major uniformity problems in plasma processing for microelectronics and flat panel display industries. Furthermore, some methods for improving the plasma uniformity are also described and compared.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.374
Times cited: 10
DOI: 10.1116/1.4907926
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“Fluid simulation of the bias effect in inductive/capacitive discharges”. Zhang Y-R, Gao F, Li X-C, Bogaerts A, Wang Y-N, Journal of vacuum science and technology: A: vacuum surfaces and films 33, 061303 (2015). http://doi.org/10.1116/1.4928033
Abstract: Computer simulations are performed for an argon inductively coupled plasma (ICP) with a capacitive radio-frequency bias power, to investigate the bias effect on the discharge mode transition and on the plasma characteristics at various ICP currents, bias voltages, and bias frequencies. When the bias frequency is fixed at 13.56 MHz and the ICP current is low, e.g., 6A, the spatiotemporal averaged plasma density increases monotonically with bias voltage, and the bias effect is already prominent at a bias voltage of 90 V. The maximum of the ionization rate moves toward the bottom electrode, which indicates clearly the discharge mode transition in inductive/capacitive discharges. At higher ICP currents, i.e., 11 and 13 A, the plasma density decreases first and then increases with bias voltage, due to the competing mechanisms between the ion acceleration power dissipation and the capacitive power deposition. At 11 A, the bias effect is still important, but it is noticeable only at higher bias voltages. At 13 A, the ionization rate is characterized by a maximum at the reactor center near the dielectric window at all selected bias voltages, which indicates that the ICP power, instead of the bias power, plays a dominant role under this condition, and no mode transition is observed. Indeed, the ratio of the bias power to the total power is lower than 0.4 over a wide range of bias voltages, i.e., 0300V. Besides the effect of ICP current, also the effect of various bias frequencies is investigated. It is found that the modulation of the bias power to the spatiotemporal distributions of the ionization rate at 2MHz is strikingly different from the behavior observed at higher bias frequencies. Furthermore, the minimum of the plasma density appears at different bias voltages, i.e., 120V at 2MHz and 90V at 27.12 MHz.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.374
Times cited: 9
DOI: 10.1116/1.4928033
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“Influence of sticking coefficients on the behavior of sputtered atoms in an argon glow discharge: modeling and comparison with experiment”. Bogaerts A, Naylor J, Hatcher M, Jones WJ, Mason R, Journal of vacuum science and technology: A: vacuum surfaces and films 16, 2400 (1998). http://doi.org/10.1116/1.581359
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.374
Times cited: 12
DOI: 10.1116/1.581359
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