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“Voltammetric assay of anti-vertigo drug betahistine hydrochloride in sodium lauryl sulphate”. Jain R, Yadav RK, Rather JA, Colloids and surfaces: A: physicochemical and engineering aspects 366, 63 (2010). http://doi.org/10.1016/J.COLSURFA.2010.05.027
Abstract: Assay and electrochemical behaviour of betahistine hydrochloride in BrittonRobinsons (BR) buffer of pH range 2.512.0 at a glassy carbon electrode have been investigated. Addition of anionic surfactant (sodium lauryl sulphate) to the betahistine hydrochloride solution containing electrolyte enhanced the reduction current signal while neutral surfactant (Tween-20) and cationic surfactant cetyl trimethylammonium bromide (CTAB) showed an opposite effect. Voltammograms of betahistine hydrochloride exhibited a single wave. Based on reduction behaviour of betahistine hydrochloride, a direct square-wave voltammetric method has been developed for the assay of betahistine hydrochloride in pharmaceutical formulation. The proposed method has been validated as per ICH guideline. System and method precision in terms of RSD were 1.88% and 1.60% respectively, whereas the method accuracy was indicated by the recovery of 97.6101.9%. Reduction peak current was linear over the target concentration with correlation coefficient 0.998. The proposed method was successfully applied to the determination of betahistine hydrochloride in pharmaceutical formulation. The results were compared with those obtained by the reference high performance liquid chromatographic method. No significant differences were found between results of proposed and reference methods.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.COLSURFA.2010.05.027
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“Voltammetric behaviour of drotaverine hydrochloride in surfactant media and its enhancement determination in Tween-20”. Jain R, Vikas, Rather JA, Colloids and surfaces: B : biointerfaces 82, 333 (2011). http://doi.org/10.1016/J.COLSURFB.2010.09.005
Abstract: Simple, sensitive and rapid adsorptive voltammetric behaviour of drotaverine hydrochloride onto the HMDE has been explored and validated in surfactant media by using cyclic, differential pulse and square-wave voltammetry. Addition of Tween-20 to the drotaverine hydrochloride containing electrolyte enhances the reduction current signal. The voltammograms of the drug with Tween-20 in phosphate buffers of pH 2.511.0 exhibit a single well defined reduction peak which may be due to the reduction of Cdouble bond; length as m-dashC group. The cyclic voltammetric studies indicated the reduction of drotaverine hydrochloride at the electrode surface through two electron irreversible step and diffusion-controlled. The peak current showed a linear dependence with the drug concentration over the range 0.87.2 μg mL−1. The calculated LOD and LOQ are 1.8 and 6.0 ng mL−1 by SWCAdSV and 8.1 and 27.2 ng mL−1 by DPCAdSV, respectively. The procedure was applied to the assay of the drug in tablet form with mean percentage recoveries of 100.2% with SWCAdSV and 99.7% with DPCAdSV. The validity of the proposed methods was further assessed by applying a standard addition technique.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.COLSURFB.2010.09.005
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“Voltammetric determination of antibacterial drug gemifloxacin in solubilized systems at multi-walled carbon nanotubes modified glassy carbon electrode”. Jain R, Rather JA, Colloids and surfaces: B : biointerfaces 83, 340 (2011). http://doi.org/10.1016/J.COLSURFB.2010.12.003
Abstract: A sensitive electroanalytical method for determination of gemifloxacin in pharmaceutical formulation has been investigated on the basis of the enhanced electrochemical response at multi-walled carbon nanotubes modified glassy carbon electrode in the presence of CTAB. Solubilized system of different surfactants including SDS, Tween-20 and CTAB were taken for the study of electrochemical behaviour of gemifloxacin at modified electrode. The reduction peak current increases in the presence of CTAB while other surfactants show opposite effect. The modified electrode exhibits catalytic activity, high sensitivity, stability and is applicable over wide range of concentration for the determination of gemifloxacin. The mechanism of electrochemical reduction of gemifloxacin has been proposed on the basis of CV, SWV, DPV and coulometeric techniques. The proposed squarewave voltammetric method shows linearity over the concentration range 2.4715.5 μg/mL. The achieved limits of detection (LOD) and quantification (LOQ) are 0.90 ng/mL and 3.0 ng/mL respectively.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.COLSURFB.2010.12.003
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“Morphology and the chemical make-up of the inorganic components of black corals”. Nowak D, Florek M, Nowak J, Kwiatek W, Lekki J, Chevallier P, Hacura A, Wrzalik R, Ben-Nissan B, Van Grieken R, Kuczumow A, Materials science and engineering: part C: biomimetic materials 29, 1029 (2009). http://doi.org/10.1016/J.MSEC.2008.08.028
Abstract: Black corals (Cnidaria, Antipatharia) from three different sources were investigated with the aim of detecting inorganic components and their morphology. In general, the skeleton of black corals was composed of the chitin fibrils admixed with peptides and the chitin presence was confirmed by the X-ray diffraction (XRD), Fourier Transformed Infrared Spectrometry (FTIR) and microRaman Microscopy, the latter giving the opportunity of tracing single fibrils and their location. The composition and concentrations of the inorganic components of the black corals were measured, using a scanning electron microprobe and micro-Particle Induced X-ray Emission (µ-PIXE). The application of such instruments enabled the estimation of the constituent distributions in a microscale. The mapping option was the most useful technique of making analyses in these studies, just to reveal the composition of chamber-like cells. Analysis of the morphology and microstructure showed that there were three distinct regions within the coral: a core and the cells encircled with adjacent interface gluing strips. The majority of the elements analyzed were selectively distributed and segregated in a striking way in mentioned distinctive zones of the skeleton and it was detected for the first time. The core area was characterized by the relatively elevated concentrations of Ca. The measurements gave extremely clear images of the distribution of particular elements in the skeletal tissue, with I, Ca, K and Fe much more concentrated in the gluing zones, while C, N, Na and Mg present in the interiors of particular skeletal cells. The distribution of some elements (Mg, Fe) and some compounds (chitin) and functional groups (SS, CI) allows differentiating the biological and mechanical functions of particular fragments of the rods. The kinds of elements and their concentrations measured were essentially in compliance with rare data available in the literature. The Raman technique gave the additional qualitative information about the structure of gluing zone and the chitin fibrils and surrounding matrix inside the cell interior.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.MSEC.2008.08.028
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“Voltammetric behaviour of nitroxazepine in solubilized system and biological fluids”. Jain R, Rather JA, Dwivedi A, Materials science and engineering: part C: biomimetic materials 31, 230 (2011). http://doi.org/10.1016/J.MSEC.2010.09.001
Abstract: This study reports the development and validation of sensitive and selective assay method for the determination of the antidepressant drug in solubilized system and biological fluids. Solubilized system of different surfactants including cationic, anionic and non-ionic influences the electrochemical response of drug. Addition of cationic surfactant cetrimide to the solution containing drug enhances the peak current signal while anionic and non-ionic showed an opposite effect. The current signal due to reduction process was function of concentration of nitroxazepine, pH, type of surfactant and preconcentration time at the electrode surface. The reduction process is irreversible and adsorption controlled at HMDE. Various chemical and instrumental parameters affecting the monitored electroanalytical response were investigated and optimized for niroxazepine hydrochloride determination. The proposed SWCAdSV and DPCAdSV methods are linear over the concentration range 2.0 × 10-7 5.0 × 10-9 mol/L and 6.1 × 10-7 1.0 × 10-8 mol/L with detection limit of 1.62 × 10-10 mo/L and 1.4 × 10-9 mo/L respectively. The method shows good sensitivity, selectivity, accuracy and precision that makes it very suitable for determination of nitroxazepine in pharmaceutical formulation and biological fluids.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.MSEC.2010.09.001
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“Leaf area-length allometry and its implications in leaf shape evolution”. Shi P, Liu M, Ratkowsky DA, Gielis J, Su J, Yu X, Wang P, Zhang L, Lin Z, Schrader J, Trees: structure and function 33, 1073 (2019). http://doi.org/10.1007/S00468-019-01843-4
Abstract: According to Thompson’s principle of similarity, the area of an object should be proportional to its length squared. However, leaf area–length data of some plants have been demonstrated not to follow the principle of similarity. We explore the reasons why the leaf area–length allometry deviates from the principle of similarity and examine whether there is a general model describing the relationship among leaf area, width and length. We sampled more than 11,800 leaves from six classes of woody and herbaceous plants and tested the leaf area–length allometry. We compared six mathematical models based on root-mean-square error as the measure of goodness-of-fit. The best supported model described a proportional relationship between leaf area and the product of leaf width and length (i.e., the Montgomery model). We found that the extent to which the leaf area–length allometry deviates from the principle of similarity depends upon the extent of variation of the ratio of leaf width to length. Estimates of the parameter of the Montgomery model ranged between 1/2, which corresponds to a triangular leaf with leaf length as its height and leaf width as its base, and π/4, which corresponds to an elliptical leaf with leaf length as its major axis and leaf width as its minor axis, for the six classes of plants. The narrow range in practice of the Montgomery parameter implies an evolutionary stability for the leaf area of large-leaved plants despite the fact that leaf shapes of these plants are rather different.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1007/S00468-019-01843-4
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“Einfluss verschiedener Silbersalze auf die Farbintensität von Silbergelb : analytische Untersuchungen”. De Vis K, Jembrih-Simbürger D, Schalm O, Schreiner M, Caen J, Zeitschrift für Kunsttechnologie und Konservierung 16, 147 (2002)
Keywords: A2 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Phosphorus, calcium and lead distribution in collagen in lead induced soft tissue calcification : an ultrastructural and X-ray microanalytical study”. Vandeputte DF, Jacob WA, Van Grieken RE, Matrix 10, 33 (1990). http://doi.org/10.1016/S0934-8832(11)80135-6
Abstract: Repeated intraperitoneal injections of lead acetate in rats caused a calcification of the skin of the abdomen near the site of the injections. In the lead-induced calcifications, electron dense collagen bundles could be observed. On the surface of the collagen fibrils, needle-like crystals were visible. With energy-dispersive X-ray analysis, phosphorus, calcium and lead were detected in the electron dense collagen bundles. X-ray maps of the P-Kα, Ca-Kα, and Pb-Lα plus Pb-Lβ lines showed an equivalent distribution along the collagen fibrils for phosphorus and calcium. The occurrence of the most electron dense areas in the STEM-image was comparable to the lead distribution. A good correlation existed between the structural and the elemental images of the same area. Although the medicinal use of preparations containing lead is no longer recommended, some are still prescribed. From our results we can conclude that they should not be applied to injured or inflamed skin.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/S0934-8832(11)80135-6
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“Mathematical description of a direct current glow discharge in argon”. Bogaerts A, Gijbels R, Fresenius' journal of analytical chemistry 355, 853 (1996)
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Times cited: 12
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“Micro-heterogeneity study of trace elements in BCR CRM 680 by means of synchrotron micro-XRF”. Kempenaers L, de Koster C, van Borm W, Janssens K, Fresenius' journal of analytical chemistry 369, 733 (2001). http://doi.org/10.1007/S002160000679
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 15
DOI: 10.1007/S002160000679
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“The non-destructive determination of REE in fossilized bone using synchrotron radiation induced K-line X-ray microfluorescence analysis”. Janssens K, Vincze L, Vekemans B, Williams CT, Radtke M, Haller M, Knöchel A, Fresenius' journal of analytical chemistry 363, 413 (1999). http://doi.org/10.1007/S002160051212
Abstract: The sensitivity and applicability of the synchrotron radiation induced X-ray microfluorescence (mu-SRXRF) spectrometer at the Hamburg synchrotron laboratory Hasylab for the determination of the distribution of trace concentrations of rare-earth elements (REE) in fossilized bone are discussed and critically compared to those of other trace analytical methods such as instrumental neutron activation analysis (INAA) and LAMP-ICPMS (laser ablation microprobe inductively-coupled plasma mass spectrometry). Measurements were carried out on two bone samples from contrasting terrestrial depositional environments at Olduvai Gorge (Tanzania). Results indicate that the microdistribution of the REE in these biological materials is not homogeneous and that the relative abundance of these elements can provide information on the palaeoenvironment during the fossilization process. The heterogeneous distribution of the REE can be determined in a quantitative and completely non-destructive manner provided the concentrations of individual REE are above 10 mu g/g.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S002160051212
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“Applications of micro-analysis to individual environmental particles”. Jambers W, de Bock L, Van Grieken R, Fresenius' journal of analytical chemistry 355, 521 (1996). http://doi.org/10.1007/S0021663550521
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S0021663550521
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“Performance of total reflection and grazing emission X-ray fluorescence spectrometry for the determination of trace metals in drinking water in relation to other analytical techniques”. Hołynska B, Olko M, Ostachowicz B, Ostachowicz J, Wegrzynek D, Claes M, Van Grieken R, de Bokx P, Kump P, Necemer M, Fresenius' journal of analytical chemistry 362, 294 (1998). http://doi.org/10.1007/S002160051077
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S002160051077
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“Quantitative characterization of individual particle surfaces by fractal analysis of scanning electron microscope images”. van Put A, Vertes A, Wegrzynek D, Treiger B, Van Grieken R, Fresenius' journal of analytical chemistry 350, 440 (1994). http://doi.org/10.1007/BF00321787
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/BF00321787
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“The use of a secondary cathode to analyse solid non-conducting samples with direct current glow discharge mass spectrometry: potential and restrictions”. Schelles W, de Gendt S, Maes K, Van Grieken R, Fresenius' journal of analytical chemistry 355, 858 (1996). http://doi.org/10.1007/S0021663550858
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S0021663550858
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“A GLUE uncertainty analysis of a drying model of pharmaceutical granules”. Mortier STFC, Van Hoey S, Cierkens K, Gernaey KV, Seuntjens P, De Baets B, De Beer T, Nopens I, European journal of pharmaceutics and biopharmaceutics 85, 984 (2013). http://doi.org/10.1016/J.EJPB.2013.03.012
Abstract: A shift from batch processing towards continuous processing is of interest in the pharmaceutical industry. However, this transition requires detailed knowledge and process understanding of all consecutive unit operations in a continuous manufacturing line to design adequate control strategies. This can be facilitated by developing mechanistic models of the multi-phase systems in the process. Since modelling efforts only started recently in this field, uncertainties about the model predictions are generally neglected. However, model predictions have an inherent uncertainty (i.e. prediction uncertainty) originating from uncertainty in input data, model parameters, model structure, boundary conditions and software. In this paper, the model prediction uncertainty is evaluated for a model describing the continuous drying of single pharmaceutical wet granules in a six-segmented fluidized bed drying unit, which is part of the full continuous from-powder-to-tablet manufacturing line (Consigma (TM), GEA Pharma Systems). A validated model describing the drying behaviour of a single pharmaceutical granule in two consecutive phases is used. First of all, the effect of the assumptions at the particle level on the prediction uncertainty is assessed. Secondly, the paper focuses on the influence of the most sensitive parameters in the model. Finally, a combined analysis (particle level plus most sensitive parameters) is performed and discussed. To propagate the uncertainty originating from the parameter uncertainty to the model output, the Generalized Likelihood Uncertainty Estimation (GLUE) method is used. This method enables a modeller to incorporate the information obtained from the experimental data in the assessment of the uncertain model predictions and to find a balance between model performance and data precision. A detailed evaluation of the obtained uncertainty analysis results is made with respect to the model structure, interactions between parameters and uncertainty boundaries. (C) 2013 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Pharmacology. Therapy; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.EJPB.2013.03.012
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“Heavy metals distribution in the sediments of Ganges and Brahmaputra rivers”. Subramanian V, Van Grieken R, Van 't dack L, Environmental geology 9, 93 (1987). http://doi.org/10.1007/BF02449940
Abstract: Bed sediments were collected from the entire region of the Ganges basin and some parts of the Brahmaputra. In addition, selected stations were sampled for suspended sediments as well. The samples were analysed for a number of heavy metals (Fe, Mn, Ni, Cr, Cu, and Zn) by the thin-film energy dispersive X-ray fluorescence technique. There are pronounced temporal and spatial variations in the heavy metals distributions. Suspended sediments are 510 times richer than the bed sediments. None of the tributaries contribute significant heavy metal load, but around urban areas in Yamuna (tributary of Ganges), very high levels due to the distribution from the drainage network are observed. Compared to the Brahmaputra, the distribution and fractionation of heavy metals in the Ganges sediments are more erratic and highly variable. All the metals considered show high correlation among themselves. Given the high flux of suspended sediments from the Himalayan rivers (nearly 20% of the global flux), the worldwide budget for heavy metal transport may need to be suitably revised.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/BF02449940
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“Field demonstration and evaluation of the passive flux meter on a CAH groundwater plume”. Verreydt G, Annable MD, Kaskassian S, van Keer I, Bronders J, Diels L, Vanderauwera P, Environmental Science and Pollution Research 20, 4621 (2013). http://doi.org/10.1007/S11356-012-1417-8
Abstract: This study comprises the first application of the Passive Flux Meter (PFM) for the measurement of chlorinated aliphatic hydrocarbon (CAH) mass fluxes and Darcy water fluxes in groundwater at a European field site. The PFM was originally developed and applied to measurements near source zones. The focus of the PFM is extended from near source to plume zones. For this purpose, 48 PFMs of 1.4 m length were constructed and installed in eight different monitoring wells in the source and plume zone of a CAH-contaminated field site located in France. The PFMs were retrieved, sampled, and analyzed after 3 to 11 weeks of exposure time, depending on the expected contaminant flux. PFM evaluation criteria include analytical, technical, and practical aspects as well as conditions and applicability. PFM flux data were compared with so-called traditional soil and groundwater concentration data obtained using active sampling methods. The PFMs deliver reasonable results for source as well as plume zones. The limiting factor in the PFM applicability is the exposure time together with the groundwater flux. Measured groundwater velocities at the field site range from 2 to 41 cm/day. Measured contaminant flux data raise up to 13 g/m(2)/day for perchloroethylene in the plume zone. Calculated PFM flux averaged concentration data and traditional concentration data were of similar magnitude for most wells. However, both datasets need to be compared with reservation because of the different sampling nature and time. Two important issues are the PFM tracer loss during installation/extraction and the deviation of the groundwater flow field when passing the monitoring well and PFM. The demonstration of the PFM at a CAH-contaminated field site in Europe confirmed the efficiency of the flux measurement technique for source as well as plume zones. The PFM can be applied without concerns in monitoring wells with European standards. The acquired flux data are of great value for the purpose of site characterization and mass discharge modeling, and can be used in combination with traditional soil and groundwater sampling methods.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Biochemical Wastewater Valorization & Engineering (BioWaVE)
DOI: 10.1007/S11356-012-1417-8
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“Health implications of atmospheric aerosols from asbestos-bearing road pavements traditionally used in Southern Brazil”. Godoi RHM, Goncalves SJ Jr, Sayama C, Polezer G, Reis Neto JM, Alfoldy B, Van Grieken R, Riedi CA, Yamamoto CI, Godoi AFL, Bencs L, Environmental Science and Pollution Research
T2 –, 1st International Caparica Conference on Pollutant Toxic Ions and, Molecules (PTIM), 2015, Caparica, PORTUGAL 23, 25180 (2016). http://doi.org/10.1007/S11356-016-7586-0
Abstract: Serpentine and amphibole asbestos occur naturally in certain geologic settings worldwide, most commonly in association with ultramafic rocks, along associated faults. Ultramafic rocks have been used in Pin County, Southern Brazil for decades for the purpose of road paving in rural and urban areas, but without the awareness of their adverse environmental and health impact. The aim of this study was the chemical characterization of aerosols re-suspended in two rural roads of Pin, paved with ultramafic rocks and to estimate the pulmonary deposition of asbestos aerosols. Bulk aerosol samples were analyzed by means of X-ray fluorescence spectrometry and X-ray diffraction analysis, in order to characterize elemental composition and crystallinity. Single-particle compositions of aerosols were analyzed by computer-controlled electron-probe microanalysis, indicating the presence of a few percentages of serpentine and amphibole. Given the chemical composition and size distribution of aerosol particles, the deposition efficiency of chrysotile, a sub-group of serpentine, in two principal segments of the human respiratory system was estimated using a lung deposition model. As an important finding, almost half of the inhaled particles were calculated to be deposited in the respiratory system. Asbestos depositions were significant (similar to 25 %) in the lower airways, even though the selected breathing conditions (rest situation, nose breathing) implied the lowest rate of respiratory deposition. Considering the fraction of inhalable suspended chrysotile near local roads, and the long-term exposure of humans to these aerosols, chrysotile may represent a hazard, regarding more frequent development of lung cancer in the population of the exposed region.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S11356-016-7586-0
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“Sorption and desorption of organophosphate esters with different hydrophobicity by soils”. Cristale J, Álvarez-Martín A, Rodriguez-Cruz S, Sanchez-Martin MJ, Lacorte S, Environmental Science and Pollution Research 24, 27870 (2017). http://doi.org/10.1007/S11356-017-0360-0
Abstract: Organophosphate esters (OPEs) are ubiquitous contaminants with potentially hazardous effects on both the environment and human health. Knowledge about the soil sorption-desorption process of organic chemicals is important in order to understand their fate, mobility, and bioavailability, enabling an estimation to be made of possible risks to the environment and biota. The aim of this study was to use the batch equilibrium technique to evaluate the sorption-desorption behavior of seven OPEs (TCEP, TCPP, TBEP, TDCP, TBP, TPhP, and EHDP) in soils with distinctive characteristics (two unamended soils and a soil amended with sewage sludge). The equilibrium concentrations of the OPEs were determined by high performance liquid chromatography coupled to a triple quadrupole mass spectrometer (HPLC-MS/MS). All the compounds were sorbed by the soils, and soil organic carbon (OC) played an important role in this process. The sorption of the most soluble OPEs (TCEP, TCPP, and TBEP) depended on soil OC content, although desorption was 58.1%. The less water-soluble OPEs (TDCP, TBP, TPhP, and EHDP) recorded total sorption (100% for TPhP and EHDP) or very high sorption (34.9%) by all the soils and were not desorbed, which could be explained by their highly hydrophobic nature, as indicated by the logarithmic octanol/water partition coefficient (K-ow) values higher than 3.8, resulting in a high affinity for soil OC. The results of the sorption-desorption of the OPEs by soils with different characteristics highlighted the influence of these compounds' physicochemical properties and the content and nature of soil OC in this process.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S11356-017-0360-0
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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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“Chemical composition of building materials used in Turkey”. Čevik U, Damla N, Van Grieken R, Vefa Akpinar M, Construction and building materials 25, 1546 (2011). http://doi.org/10.1016/J.CONBUILDMAT.2010.08.011
Abstract: The main goal of this work was to determine the chemical composition of building materials used in Turkey by utilizing energy dispersive X-ray fluorescence (EDXRF) spectrometry. Gas concrete, cement, sand, bricks, roofing tiles, marble, lime and gypsum materials were selected as building materials for this research. The chemical contents and their trace concentrations of the selected samples were determined. The most abundant oxides measured were generally SiO2, Al2O3, CaO, MgO, Fe2O3, K2O and SO3 for all samples. While the main chemical component of gas concrete, cement, sand and marble samples were SiO2 and CaO, brick and roofing tile mainly consisted of SiO2 and Al2O3. CaO and SO3 were major component of lime and gypsum samples, respectively. For U and Th concentrations in the samples, activities of 226Ra and 232Th were measured by utilizing gamma spectrometry. ANOVA and Pearson correlation analyses were performed on the studied data for statistical analysis.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.CONBUILDMAT.2010.08.011
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“Salt-induced decay in calcareous stone monuments and buildings in a marine environment in SW France”. Cardell C, Delalieux F, Roumpopoulos K, Moropoulou A, Auger F, Van Grieken R, Construction and building materials 17, 165 (2003). http://doi.org/10.1016/S0950-0618(02)00104-6
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/S0950-0618(02)00104-6
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“Structural aspects of the combination of Si and YBa2Cu3O7-x”. Vasiliev AL, Van Tendeloo G, Boikov Y, Olsson E, Ivanov Z, Claeson T, Kiselev NA, Institute of physics conference series 146, 333 (1995)
Abstract: The microstructure of defects and interfaces as well as interfacial reactions of the YBa2Cu3O7-x (YBCO) thin films on Si or Si on sapphire with single Y-stabilized ZrO2 (YSZ), double CeO2/YSZ or triple MgO/CeO2/YSZ buffer layer has been characterized by transmission electron microscopy The complex buffer made it possible to prevent detrimental interdiffusion and to control the orientation of YBCO layers.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
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“A microanalytical study of the gills of aluminium-exposed catfish”. Eeckhaoudt S, Landsberg J, Van Grieken R, Jacob W, Watt F, Witters H, Institute of physics conference series
T2 –, Proceedings of the 13th International Congress on X-Ray Optics and Microanalysis / Kenway, P.B. [edit.] , 251 (1993)
Abstract: Through a combined use of light- and electron microscopy with microanalytical techniques, the aluminium distribution in gills of aluminium-exposed catfish was investigated. This study demonstrates that also with the ''acid-resistant'' catfish, exposed during seven days to acidified water (pH=4.3) with an elevated aluminium concentration (1 mg Al/l), aluminium can be found at, and even in, the gills.
Keywords: P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Desorption-ionization of inorganic compounds in Fourier transform laser microprobe mass spectrometry with external ion source”. Struyf H, Van Vaeck L, Van Grieken R, Rapid communications in mass spectrometry 10, 551 (1996). http://doi.org/10.1002/(SICI)1097-0231(19960331)10:5<551::AID-RCM414>3.0.CO;2-S
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/(SICI)1097-0231(19960331)10:5<551::AID-RCM414>3.0.CO;2-S
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“Improving footprint calculations of small open economies : combining local with multi-regional input-output tables”. Christis M, Geerken T, Vercalsteren A, Vrancken KCM, Economic systems research 29, 25 (2017). http://doi.org/10.1080/09535314.2016.1245653
Abstract: In a small, open and resource-poor economy, import and export dependency have an ever-growing impact on local policy decisions, which makes local (environmental) policy-makers increasingly depend on global data. This increases the interest in models that link local production and consumption data to global production, trade and environmental data. The recent increase in availability of global environmentally extended multi-regional input-output tables (EE-MRIO tables) provides an opportunity to link them with existing local environmentally extended input-output tables (EE-RIO tables). These combined tables make it possible (1) to analyse the links between local and global production and consumption and (2) to study global value chains, material use and environmental impacts simultaneously. However, estimations using input-output (I-O) analyses contain errors due to imperfect databases. In this article the magnitude of specification, aggregation and time errors are estimated and compared. The results show the need to combine local datasets with multi-regional ones and show that highest detailed (country and sector levels) as well as time series of I-O tables are the way forward for using I-O analyses in local policy-making. The paper provides guidance on trading off investments in model adoption and/or extension and the reliability of estimation results.
Keywords: A1 Journal article; Economics; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1080/09535314.2016.1245653
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“Self-assembled vortex crystals induced by inhomogeneous magnetic textures”. Menezes RM, Sardella E, Cabral LRE, de Souza Silva CC, Journal of physics : condensed matter 31, 175402 (2019). http://doi.org/10.1088/1361-648X/AB035A
Abstract: We investigate the self-assembly of vortices in a type-II superconducting disk subjected to highly nonuniform confining potentials produced by inhomogeneous magnetic textures. Using a series of numerical experiments performed within the Ginzburg–Landau theory, we show that vortices can arrange spontaneously in highly nonuniform, defect-free crystals, reminiscent of conformal lattices, even though the strict conditions for the conformal crystal are not fulfilled. These results contradict continuum-limit theory, which predicts that the order of a nonuniform crystal is unavoidably frustrated by the presence of topological defects. By testing different cooling routes of the superconductor, we observed several different self-assembled configurations, each of which corresponding to one in a set of allowed conformal transformations, which depends on the magnetic and thermal histories of the system.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1088/1361-648X/AB035A
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“Valley filtering in graphene due to substrate-induced mass potential”. da Costa DR, Chaves A, Farias GA, Peeters FM, Journal of physics : condensed matter 29, 215502 (2017). http://doi.org/10.1088/1361-648X/AA6B24
Abstract: The interaction of monolayer graphene with specific substrates may break its sublattice symmetry and results in unidirectional chiral states with opposite group velocities in the different Dirac cones (Zarenia et al 2012 Phys. Rev. B 86 085451). Taking advantage of this feature, we propose a valley filter based on a transversal mass kink for low energy electrons in graphene, which is obtained by assuming a defect region in the substrate that provides a change in the sign of the substrate-induced mass and thus creates a non-biased channel, perpendicular to the kink, for electron motion. By solving the time-dependent Schrodinger equation for the tight-binding Hamiltonian, we investigate the time evolution of a Gaussian wave packet propagating through such a system and obtain the transport properties of this graphene-based substrate-induced quantum point contact. Our results demonstrate that efficient valley filtering can be obtained, provided: (i) the electron energy is sufficiently low, i.e. with electrons belonging mostly to the lowest sub-band of the channel, and (ii) the channel length (width) is sufficiently long (narrow). Moreover, even though the transmission probabilities for each valley are significantly affected by impurities and defects in the channel region, the valley polarization in this system is shown to be robust against their presence.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 15
DOI: 10.1088/1361-648X/AA6B24
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“The work function of few-layer graphene”. Leenaerts O, Partoens B, Peeters FM, Volodin A, van Haesendonck C, Journal of physics : condensed matter 29, 035003 (2017). http://doi.org/10.1088/0953-8984/29/3/035003
Abstract: A theoretical and experimental study of the work function of few-layer graphene is reported. The influence of the number of layers on the work function is investigated in the presence of a substrate, a molecular dipole layer, and combinations of the two. The work function of few-layer graphene is almost independent of the number of layers with only a difference between monolayer and multilayer graphene of about 60 meV. In the presence of a charge-donating substrate the charge distribution is found to decay exponentially away from the substrate and this is directly reflected in the work function of few-layer graphene. A dipole layer changes the work function only when placed in between the substrate and few-layer graphene through a change of the charge transfer between the two.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 61
DOI: 10.1088/0953-8984/29/3/035003
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