“Micro-Raman spectroscopy for the analysis of environmental particles”. Potgieter-Vermaak S, Worobiec A, Darchuk L, Van Grieken R page 193 (2011).
Keywords: H1 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP)
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“Monitoring of tropospheric ozone in the ambient air with passive samplers”. Alejo ellys, Morales MC, Nuñez V, Bencs L, Van Grieken R, van Espen P, Microchemical journal 99, 383 (2011). http://doi.org/10.1016/J.MICROC.2011.06.010
Abstract: Two sampling campaigns in suburban places in the north zone of Santa Clara city, Cuba, have been carried out on a weekly base with the use of Radiello passive diffusion tubes in order to monitor the tropospheric ozone (O3) levels in 2010. The first campaign was scheduled from February to April (cold season) and the second one in August and October (warm season), both of them at two sampling sites, i.e., Farm and School of Art Instructors. After aqueous extraction, the samples were analyzed by UVVIS spectrophotometry. A seasonal trend was observed with the maximum O3 concentrations in the cold season and the minimum levels in the warm season. Samples collected during the cold season showed the highest O3 levels. Higher levels were reached at the Farm site with average values of about 58 ± 12 μg/m3, which exceeded the limit of the Cuban Standard 99:1999. In the warm season, the O3 concentrations were similar for both sites, but lower than those observed in the cold season. The overall, seasonal average value was found to be 24 μg/m3. Despite the higher weekly average temperatures in August, the O3 concentrations during this month showed the lowest values of the whole sampling period, which finding is in agreement with that reported by the Meteorological Institute of Cuba. Mathematical models, based on the Cochrane-Orcutt algorithm, were fitted to the acquired data set to explain the change in the tropospheric ozone concentrations under various meteorological conditions during the two campaigns. The correlation coefficients for both the cold and the warm seasons demonstrated a strong correlation, i.e., 0.779 and 0.951, respectively. The high correlation of wind speed in the model from the first sampling campaign explains the sharp decrease in O3 concentrations at the SAI sampling site from the sixth week of sampling.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.MICROC.2011.06.010
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“Multiscale modeling of radiation damage and annealing in Si samples implanted with 57-Mn radioactive ions”. Abreu Y, Cruz CM, van Espen P, Piñera I, Leyva A, Cabal AE, IEEE conference record
T2 –, IEEE Nuclear Science Symposium/Medical Imaging Conference (NSS/MIC)/18th, International Workshop on Room-Temperature Semiconductor X-Ray and, Gamma-Ray Detectors, OCT 23-29, 2011, Valencia, SPAIN , 1754 (2011)
Abstract: The radiation damage created in silicon materials by Mn-57 -> Fe-57 ion implantation has been studied and characterized by Mossbauer spectroscopy showing four main lines, assigned to: substitutional, interstitial and damaged configuration sites of the implanted ions. Nevertheless, the Mossbauer spectrum of Fe-57 in this materials remains with some ambiguous identification regarding the implantation configurations before and after annealing, specially the damaged configurations and its evolution. In the present work some possible implantation configurations are suggested and evaluated using a multiscale approach by Monte Carlo ion transport and electronic structure calculations within DFT. The proposed implantation environments were evaluated in terms of stability and the Fe-57 hyperfine parameters were calculated to establish the connections with the experimental observations. Good agreement was found between the experimental and the calculated hyperfine parameters for some configurations; suggesting which ones could be the implantation environments before and after sample annealing.
Keywords: P1 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Platinum : environmental pollution and health effects”. Bencs L, Ravindra K, Van Grieken R page 580 (2011).
Keywords: H2 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Radiation damage evaluation on LYSO and LuYAP materials through Dpa calculation assisted by Monte Carlo method”. Piñera I, Abreu Y, van Espen P, Diaz A, Leyva A, Cruz CM, IEEE conference record
T2 –, IEEE Nuclear Science Symposium/Medical Imaging Conference (NSS/MIC)/18th, International Workshop on Room-Temperature Semiconductor X-Ray and, Gamma-Ray Detectors, OCT 23-29, 2011, Valencia, SPAIN , 1609 (2011)
Abstract: The aim of the present work is to study the radiation damage induced in LYSO and LuYAP crystals by the gamma radiation and the secondary electrons/positrons generated. The displacements per atom (dpa) distributions inside each material were calculated following the Monte Carlo assisted Classical Method (MCCM) introduced by the authors. As gamma sources were used Sc-44, Na-22 and V-48. Also the energy of gammas from the annihilation processes (511 keV) was included in the study. This procedure allowed studying the in-depth dpa distributions inside each crystal for all four sources. It was also possible to obtain the separate contribution from each atom to the total dpa. The LYSO crystals were found to receive more damage, mainly provoked by the displacements of silicon and oxygen atoms.
Keywords: P1 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Raman spectroscopy for the analysis of coal : a review”. Potgieter-Vermaak S, Maledi N, Wagner N, van Heerden JHP, Van Grieken R, Potgieter JH, Journal of Raman spectroscopy 42, 123 (2011). http://doi.org/10.1002/JRS.2636
Abstract: The advances in the characterization of amorphous carbons by Raman spectroscopy over the last four decades are of interest to many industries, especially those involving the combustion, gasification and pyrolysis of coal. Many researchers report on the Raman character of the natural organic matter in carbon-containing compounds, such as coal, and relate the Raman bands to the structural order of the amorphous carbons. The basis of most of these studies evolved around the assignment of the G (graphitic, ∼1580 cm−1) band to crystalline graphite and any other bands, called D bands, (disorder, various from 1100 to 1500 cm−1) to any type of structural disorder in the graphitic structure. Concerning coal analysis, the information gained by Raman investigations has been used to describe char evolution as a function of temperature, the presence of catalysts and different gasification conditions. In addition, researchers looked at maturation, grade, doppleritization and many more aspects of interest. One aspect that has, however, not been addressed by most of the researchers is the natural inorganic matter (NIM) in the carbon-containing compounds. Micro-Raman spectroscopy (MRS) has many advantages over other characterization tools, i.e. in situ analysis, nondestructive, no sample preparation, low detection limit, micrometer-scale characterization, versatility and sensitivity to many amorphous compounds. With the distinct advantages it has over that of other molecular characterization tools, such as powder X-ray diffraction (PXRD), Fourier-transform infrared spectrometry (FT-IR) and scanning electron microscopy with X-ray detection (SEM/EDS), it is surprising that it has not yet been fully exploited up to this point for the characterization of the NIM in coal and other amorphous carbons. This paper reviews the work published on the Raman characterization of the natural organic matter (NOM) of coals and reports on preliminary results of the NIM character of various South African coals, whereby various inorganic compounds and minerals in the coal have been characterized.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1002/JRS.2636
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“Research for preventive conservation and optimal presentation of world heritage in Museum Plantin-Moretus, Antwerp”. Kontozova V, Krupińska B, Van Grieken R, Janssen E, Moris H, Aerts D, Watteeuw L, van Bos M, Peckstadt A, (2011)
Keywords: P3 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Stripping voltammetry of tinidazole in solubilized system and biological fluids”. Jain R, Rather JA, Colloids and surfaces: A: physicochemical and engineering aspects 378, 27 (2011). http://doi.org/10.1016/J.COLSURFA.2011.01.045
Abstract: The adsorptive voltammetric behaviour of tinidazole onto the HMDE was investigated and validated in solubilized system and biological fluids by CV, SWCAdSV and DPCAdSV. Addition of CTAB to the solution containing drug enhanced the peak current while anionic and non-ionic surfactants showed an opposite effect. The electrode process is irreversible and adsorption controlled. Various chemical and instrumental parameters affecting the monitored electroanalytical response were investigated and optimized for tinidazole determination. Under optimized conditions; the adsorptive stripping peak current is linear over the concentration range 7.0 × 10−9 to 6.2 × 10−7 mol/L with detection limit of 4.5 × 10−10 mol/L. The precision of the proposed method in terms of RSD is 1.2% and mean recovery of 100.01%. The applicability of proposed method is further extended to in vitro determination of the drug in biological fluids.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.COLSURFA.2011.01.045
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“Structural features of human tooth tissues affected by high dose of external ionizing radiation after nuclear catastrophe of Chernobyl plant”. Darchuk LA, Zaverbna LV, Worobiec A, Van Grieken R, Microchemical journal 97, 282 (2011). http://doi.org/10.1016/J.MICROC.2010.09.016
Abstract: The application of micro-Raman spectroscopy is discussed for the analysis of structural features of human tooth tissues affected by high doses of external ionizing radiation (0.51.7 Gy) after the nuclear plant catastrophe in Chernobyl in 1986. The results have shown significant changes in the mineral matrix of dental enamel that lead to the decrease of tooth enamel hardness. Destruction of the collagen chain of the organic matrix has been observed for dentin and cementum.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP)
DOI: 10.1016/J.MICROC.2010.09.016
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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 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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“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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“X-ray spectrometry for preventive conservation of cultural heritage”. Van Grieken R, Worobiec A, Pramåna: a journal of physics 72, 191 (2011). http://doi.org/10.1007/S12043-011-0041-3
Abstract: Analytical chemistry does play a key role in the chemical characterization of the environment and it appears that X-ray spectrometry, in its many forms, is one of the most relevant analytical techniques in preventive conservation, as it is in cultural heritage research in general. X-ray spectrometry has indeed been the method of choice for the characterization of the inorganic composition of atmospheric aerosols, for a long time. We have, over the last decade, intensively used various forms of X-ray spectrometry, viz., mostly energy-dispersive X-ray fluorescence, e.g. with polarized high-energy beam excitation, and automated electron probe X-ray microanalysis, together with other techniques, to identify particle types and their sources in indoor environments, including museums, while gaseous indoor pollutants were assessed using passive diffusion samplers. In each case, both bulk aerosols and individual aerosol particles were studied. For microanalysis of single particles, we have investigated a dozen techniques, but for wide, real-life applications, automated electron probe X-ray microanalysis is the most rewarding. We have first studied atmospheric aerosols in and around the Correr Museum in Venice, many other museums in Austria, Japan and England, and in the caves with prehistoric rock paintings in Altamira, Spain. Very recently, measurements were done in the Metropolitan Museum of Art in New York and theWawel Castle in Cracow, in Italian and Polish mountain churches, in a number of museums in Belgium and the Netherlands, and in cathedrals with medieval stained glass windows. In the Correr museum, it appeared that the particles most threatening for the Bellini paintings were released by the deteriorating plaster renderings, and this could be avoided by simply improving the rendering on the museum walls. In the Wawel Castle, outdoor pollution particles, like fine soot from diesel traffic, entering via leaks in the windows and doors, and also street-deicing salts and coal burning pollution particles, brought in by visitors, mostly in winter, were found to be most worrisome. Urgent questions that are not solved at this moment pertain to the deposition processes from the atmosphere to the cultural heritage items, the critical surface interactions that take place on these items, and the establishment of suitable particle concentration standards.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP)
DOI: 10.1007/S12043-011-0041-3
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“Particle deposition in airways of chronic respiratory patients exposed to an urban aerosol”. Horemans B, Van Holsbeke C, Vos W, Darchuk L, Novakovic V, Fontan AC, de Backer J, van Grieken R, de Backer W, De Wael K, Environmental science and technology 46, 12162 (2012). http://doi.org/10.1021/es302755s
Abstract: Urban atmospheres in modern cities carry characteristic mixtures of particulate pollution which are potentially aggravating for chronic respiratory patients (CRP). Although air quality surveys can be detailed, the obtained information is not always useful to evaluate human health effects. This paper presents a novel approach to estimate particle deposition rates in airways of CRP, based on real air pollution data. By combining computational fluid dynamics with physical-chemical characteristics of particulate pollution, deposition rates are estimated for particles of different toxicological relevance, that is, minerals, iron oxides, sea salts, ammonium salts, and carbonaceous particles. Also, it enables some qualitative evaluation of the spatial, temporal, and patient specific effects on the particle dose upon exposure to the urban atmosphere. Results show how heavy traffic conditions increases the deposition of anthropogenic particles in the trachea and lungs of respiratory patients (here, +0.28 and +1.5 μg·h1, respectively). In addition, local and synoptic meteorological conditions were found to have a strong effect on the overall dose. However, the pathology and age of the patient was found to be more crucial, with highest deposition rates for toxic particles in adults with a mild anomaly, followed by mild asthmatic children and adults with severe respiratory dysfunctions (7, 5, and 3 μg·h1, respectively).
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP)
Impact Factor: 6.198
Times cited: 5
DOI: 10.1021/es302755s
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“Aptasensing of chloramphenicol in the presence of its analogues : reaching the maximum residue limit”. Pilehvar S, Mehta J, Dardenne F, Robbens J, Blust R, De Wael K, Analytical chemistry 84, 6753 (2012). http://doi.org/10.1021/AC3012522
Abstract: A novel label-free folding induced aptamer-based electrochemical biosensor for the detection of chloramphenicol (CAP) in the presence of its analogues has been developed. CAP is a broad-spectrum antibiotic which has lost its favor due to its serious adverse toxic effects on human health. Aptamers are artificial nucleic acid ligands (ssDNA or RNA) able to specifically recognize a target such as CAP. In this article, the aptamers are fixed onto a gold electrode surface by a self-assembly approach. In the presence of CAP, the unfolded ssDNA on the electrode surface changes to a hairpin structure bringing the target molecules close to the surface and trigger electron transfer. Detection limits were determined to be 1.6×10-9 mol L-1. In addition, thiamphenicol (TAP) and florfenicol (FF), antibiotics with a similar structure to CAP, did not influence the performance of the aptasensor, suggesting a good selectivity of the CAP-aptasensor. Simplicity and lower detection limit (because of the home-selected aptamers) make that the electrochemical aptasensor is suitable for practical use in the detection of CAP in milk samples.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.32
Times cited: 68
DOI: 10.1021/AC3012522
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“Assessment of the air quality (NO2, SO2, O3 and particulate matter) in the Plantin-Moretus Museum/Print Room in Antwerp, Belgium, in different seasons of the year”. Krupińska B, Worobiec A, Rotondo GG, Novaković, V, Kontozova V, Ro C-U, Van Grieken R, De Wael K, Microchemical journal 102, 49 (2012). http://doi.org/10.1016/J.MICROC.2011.11.008
Abstract: The Plantin-Moretus Museum/Print Room in Antwerp, Belgium, gathers one of the most precious collections of typographical material and old printed books in the world. Rich decorations of this former printing-house and the history of the building itself underline its uniqueness. The cultural heritage (CH) objects collected in the museum, in particular books and manuscripts are vulnerable to the atmospheric pollution and can be irreversibly damaged. To assess the air quality inside the museum, four consecutive sampling campaigns were performed in each season of the year. The gas monitoring of nitrogen dioxide (NO2), sulphur dioxide (SO2) and ozone (O3) was carried out outside the building, in galleries and in showcases by means of using diffusive samplers. The particulate matter (PM) was collected in bulk form and as single particles and then analysed with use of energy dispersive X-ray fluorescence (EDXRF) and electron probe micro-analyser (EPMA), respectively. The museum complex turned out to show good protection against gaseous pollutants, especially SO2 and O3. The concentrations of these pollutants were significantly reduced inside the building in comparison to the outdoor ones. Similar protective character of the museum complex was established in case of the coarse fraction of PM; however with some limitations. Single particle analysis showed that the relative abundance of carbon-rich particles inside the museum was greater than outside. Moreover, these particles contributed more to the fine fraction of PM than to the coarse fraction. Therefore, for better preservation of cultural heritage, special attention should be paid to the small particles and their distribution within the museum.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP)
Impact Factor: 3.034
Times cited: 25
DOI: 10.1016/J.MICROC.2011.11.008
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“Atmospheric composition and micro-climate in the Alhambra monument, Granada (Spain), in the context of preventive conservation”. Horemans B, Schalm O, De Wael K, Cardell C, Van Grieken R, IOP conference series : materials science and engineering 37, 012002 (2012). http://doi.org/10.1088/1757-899X/37/1/012002
Abstract: The world famous Alhambra monument in Granada, Southern Spain, listed as UNESCO world cultural heritage since 1984, represents probably the most beautiful example of Islamic art and architecture from the Middle Ages in Europe. It is visited by ca. 2 million people annually. Granada is situated in a natural basin, surrounded by mountains with altitudes up to 3500 m. Due to this topography and the prevailing low wind speeds, pollution-derived and especially traffic-derived particulate matter often accumulates in the urban air. In order to evaluate the potential conservation risks from the surrounding air, the atmospheric composition in the Alhambra monument was evaluated. Indoor temperature and relative humidity fluctuations were evaluated for their potential degenerative effects. Furthermore, the atmospheric composition in the Alhambra was analyzed in terms of inorganic gases (NO2, SO2, O3, and NH3) and black carbon. It was found that the open architecture protected the indoor environments from developing a potentially harmful microclimate, such as the build-up of humidity resulting from the huge number of daily tourists. On the downside, the strong ventilation made the indoor air hardly different from outdoor air, as characterized by strong diurnal temperature and relative humidity gradients and high traffic-derived pollutant levels.
Keywords: P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 1
DOI: 10.1088/1757-899X/37/1/012002
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“Chemical boundary conditions for the classification of aerosol particles using computer controlled electron probe microanalysis”. Anaf W, Horemans B, Van Grieken R, De Wael K, Talanta : the international journal of pure and applied analytical chemistry 101, 420 (2012). http://doi.org/10.1016/J.TALANTA.2012.09.051
Abstract: A method for the classification of individual aerosol particles using computer controlled electron probe microanalysis is presented. It is based on chemical boundary conditions (CBC) and enables quick and easy processing of a large set of elemental concentration data (mass%), derived from the X-ray spectra of individual particles. The particles are first classified into five major classes (sea salt related, secondary inorganic, minerals, iron-rich and carbonaceous), after which advanced data mining can be performed by examining the elemental composition of particles within each class into more detail (e.g., by ternary diagrams). The CBC method is validated and evaluated by comparing its results with the output obtained with hierarchical cluster analysis (HCA) for well-known standard particles as well as real aerosol particles collected with a cascade impactor. The CBC method gives reliable results and has a major advantage compared to HCA. CBC is based on boundary conditions that are derived from chemical logical thinking and does not require a translation of a mathematical algorithm output as does HCA. Therefore, the CBC method is more objective and enables comparison between samples without intermediate steps.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.162
Times cited: 3
DOI: 10.1016/J.TALANTA.2012.09.051
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“Combined use of synchrotron radiation based micro-X-ray fluorescence, micro-X-ray diffraction, micro-X-ray absorption near-edge, and micro-fourier transform infrared spectroscopies for revealing an alternative degradation pathway of the pigment cadmium yellow in a painting by Van Gogh”. van der Snickt G, Janssens K, Dik J, de Nolf W, Vanmeert F, Jaroszewicz J, Cotte M, Falkenberg G, Van der Loeff L, Analytical chemistry 84, 10221 (2012). http://doi.org/10.1021/AC3015627
Abstract: Over the past years a number of studies have described the instability of the pigment cadmium yellow (CdS). In a previous paper we have shown how cadmium sulfide on paintings by James Ensor oxidizes to CdSO4 center dot H2O. The degradation process gives rise to the fading of the bright yellow color and the formation of disfiguring white crystals that are present on the paint surface in approximately 50 mu m sized globular agglomerations. Here, we study cadmium yellow in the painting “Flowers in a blue vase” by Vincent van Gogh. This painting differs from the Ensor case in the fact that (a) a varnish was superimposed onto the degraded paint surface and (b) the CdS paint area is entirely covered with an opaque crust. The latter obscures the yellow color completely and thus presents a seemingly more advanced state of degradation. Analysis of a cross-sectioned and a crushed sample by combining scanning microscopic X-ray diffraction (mu-XRD), microscopic X-ray absorption near-edge spectroscopy (mu-XANES), microscopic X-ray fluorescence (mu-XRF) based chemical state mapping and scanning microscopic Fourier transform infrared (mu-FT-IR) spectrometry allowed unravelling the complex alteration pathway. Although no crystalline CdSO4 compounds were identified on the Van Gogh paint samples, we conclude that the observed degradation was initially caused by oxidation of the original CdS pigment, similar as for the previous Ensor case. However, due to the presence of an overlying varnish containing lead-based driers and oxalate ions, secondary reactions took place. In particular, it appears that upon the photoinduced oxidation of its sulfidic counterion, the Cd2+ ions reprecipitated at the paint/varnish interface after having formed a complex with oxalate ions that themselves are considered to be degradation products of the resin and/or oil in the varnish. The SO42- anions, for their part, found a suitable reaction partner in Pb2+ ions stemming from a dissolved lead-based siccative that was added to the varnish to promote its drying. The resulting opaque anglesite compound in the varnish, in combination with the underlying CdC2O4 layer at the paint/varnish interface, account for the orange-gray crust that is disfiguring the painting on a macroscopic level. In this way, the results presented in this paper demonstrate how, through a judicious combined use of several microanalytical methods with speciation capabilities, many new insights can be obtained from two minute, but highly complex and heterogeneous paint samples.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.32
Times cited: 59
DOI: 10.1021/AC3015627
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“Composition and state of alteration of 18th century glass from the Cistercian nunnery of Clairefontaine (Belgium)”. Herremans D, Cagno S, Vincke A, de Clercq W, Janssens K, Proceedings of the Society of Photo-optical Instrumentation Engineers
T2 –, Conference on Integrated Approaches to the Study of Historical Glass, (IASHG), APR 16-17, 2012, Brussels, BELGIUM , 842206 (2012). http://doi.org/10.1117/12.975247
Abstract: An extended set of 18th century glass vessels was analyzed by means of SEM-EDX (major and minor element composition) The fragmented archaeological objects were recovered from a latrine belonging to the early 18th century building phase of the nunnery of Clairefontaine, near Arlon (B). On the basis of typology and decoration, the major part of the vessels could be dated around the middle of the 18th century. Variety in color and weathering of the glass suggest differences in glassmaking recipes and in the composition and origin of raw materials. The results of the analysis show how two main compositional groups constitute about 90% of the analyzed glass set, and these are constituted by potash glass (transparent beakers) and high lime low alkali glass (green bottles). Next to these, a few potash-lime and soda glasses are also found. The type of alteration has also a clear relation with the original glass composition.
Keywords: P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1117/12.975247
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“Composition of Facon de Venise glass from early 17th century London in comparison with luxury glass of the same age”. Cagno S, de Raedt I, Jeffries T, Janssens K, Proceedings of the Society of Photo-optical Instrumentation Engineers
T2 –, Conference on Integrated Approaches to the Study of Historical Glass, (IASHG), APR 16-17, 2012, Brussels, BELGIUM , 842205 (2012). http://doi.org/10.1117/12.975212
Abstract: SEM-EDX and LA-ICP-MS analyses were performed on a set of early 17th century London glass fragments. The samples originate from two archaeological sites (Aldgate and Old Broad Street) where glass workshops were active in this period. The great majority of the samples are made of soda glass. Two distinct compositional groups are observed, each typical of one site of provenance. The samples originating from the Old Broad Street excavation feature a silica-soda-lime composition, with a moderate amount of potash. The samples from Aldgate are richer in potassium and feature higher amounts of trace elements such as Rb, Zr and Cu. The distinction between the two groups stems from different flux and silica sources used for glassmaking. A comparison with different European glass compositions of that time reveals no resemblance with genuine Venetian production, yet the composition of the Old Broad Street glass shows a close similarity to that of fragments produced 'a la facon de Venise' in Antwerp at the end of the 16th century. This coincides with historical sources attesting the arrival of glassworkers from the Low Countries in England and suggests that a transfer of technology took place near the turn of the century.
Keywords: P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 1
DOI: 10.1117/12.975212
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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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De Vis K, Cagno S, Van Mol W, Schalm O, Janssens K, Caen J (2012) The decolourization of manganese-stained glass : the conversion reaction and evaluation of its effectiveness. 463–468
Keywords: P2 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Effect of operating and sampling conditions on the exhaust gas composition of small-scale power generators”. Smits M, Vanpachtenbeke F, Horemans B, De Wael K, Hauchecorne B, Van Langenhove H, Demeestere K, Lenaerts S, PLoS ONE 7, e32825 (2012). http://doi.org/10.1371/JOURNAL.PONE.0032825
Abstract: Small stationary diesel engines, like in generator sets, have limited emission control measures and are therefore responsible for 44% of the particulate matter (PM) emissions in the United States. The diesel exhaust composition depends on operating conditions of the combustion engine. Furthermore, the measurements are influenced by the used sampling method. This study examines the effect of engine loading and exhaust gas dilution on the composition of small-scale power generators. These generators are used in different operating conditions than road-transport vehicles, resulting in different emission characteristics. Experimental data were obtained for gaseous volatile organic compounds (VOC) and PM mass concentration, elemental composition and nitrate content. The exhaust composition depends on load condition because of its effect on fuel consumption, engine wear and combustion temperature. Higher load conditions result in lower PM concentration and sharper edged particles with larger aerodynamic diameters. A positive correlation with load condition was found for K, Ca, Sr, Mn, Cu, Zn and Pb adsorbed on PM, elements that originate from lubricating oil or engine corrosion. The nitrate concentration decreases at higher load conditions, due to enhanced nitrate dissociation to gaseous NO at higher engine temperatures. Dilution on the other hand decreases PM and nitrate concentration and increases gaseous VOC and adsorbed metal content. In conclusion, these data show that operating and sampling conditions have a major effect on the exhaust gas composition of small-scale diesel generators. Therefore, care must be taken when designing new experiments or comparing literature results.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 2.806
Times cited: 5
DOI: 10.1371/JOURNAL.PONE.0032825
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“Electrochemical determination of hydrogen peroxide with cytochrome c peroxidase and horse heart cytochrome c entrapped in a gelatin hydrogel”. De Wael K, Bashir Q, van Vlierberghe S, Dubruel P, Heering HA, Adriaens A, Bioelectrochemistry: an international journal devoted to electrochemical aspects of biology and biological aspects of electrochemistry 83, 15 (2012). http://doi.org/10.1016/J.BIOELECHEM.2011.07.001
Abstract: A novel and versatile method, based on a membrane-free enzyme electrode in which both the enzyme and a mediator protein are entrapped in a gelatine hydrogel was developed for the fabrication of biosensors. As a proof of principle, we prepared a hydrogen peroxide biosensor by successfully entrapping both horse heart cytochrome c (HHC) and Saccharomyces cerevisae cytochrome c peroxidase (CCP) in a gelatin matrix which is immobilized on a gold electrode. This electrode was first pretreated with 6-mercaptohexanol. The biosensor displayed a rapid response and an expanded linear response range from 0 to 0.3 mM (R = 0.987) with a detection limit of 1 × 10− 5 M in a HEPES buffer solution (pH 7.0). This method of encapsulation is now further investigated for industrial biosensor applications.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.346
Times cited: 31
DOI: 10.1016/J.BIOELECHEM.2011.07.001
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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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“Enzyme-gelatin electrochemical biosensors : scaling down”. De Wael K, De Belder S, Pilehar S, Van Steenberge G, Herrebout W, Heering HA, Biosensors 2, 101 (2012). http://doi.org/10.3390/BIOS2010101
Abstract: In this article we investigate the possibility of scaling down enzyme-gelatin modified electrodes by spin coating the enzyme-gelatin layer. Special attention is given to the electrochemical behavior of the selected enzymes inside the gelatin matrix. A glassy carbon electrode was used as a substrate to immobilize, in the first instance, horse heart cytochrome c (HHC) in a gelatin matrix. Both a drop dried and a spin coated layer was prepared. On scaling down, a transition from diffusion controlled reactions towards adsorption controlled reactions is observed. Compared to a drop dried electrode, a spin coated electrode showed a more stable electrochemical behavior. Next to HHC, we also incorporated catalase in a spin coated gelatin matrix immobilized on a glassy carbon electrode. By spincoating, highly uniform sub micrometer layers of biocompatible matrices can be constructed. A full electrochemical study and characterization of the modified surfaces has been carried out. It was clear that in the case of catalase, gluteraldehyde addition was needed to prevent leaking of the catalase from the gelatin matrix.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Molecular Spectroscopy (MolSpec)
DOI: 10.3390/BIOS2010101
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“Evidence of early medieval soda ash glass in the archaeological site of San Genesio (Tuscany)”. Cagno S, Favaretto L, Mendera M, Izmer A, Vanhaecke F, Janssens K, Journal of archaeological science 39, 1540 (2012). http://doi.org/10.1016/J.JAS.2011.12.031
Abstract: The early medieval period marks an important turning point in the history of glassmaking, since it comprises the transition period between the mineral-based silica-soda-lime glass of the Roman tradition and the plant ash-based glass. With the aim of expanding the knowledge on the glass recipes and technologies of this period, 37 glass samples were analyzed, originating from the archaeological excavations of San Genesio (Tuscany) and dated from the fourth to the eleventh century. The major and minor element concentrations were measured with SEM-EDX, while the trace elements were quantified with LA-ICP-MS. The results were compared with published compositions of glass samples of similar age in order to highlight differences and similarities. The results offer a very interesting view on the glass circulation in the religious/residential/manufacturing center of San Genesio in the early medieval period. Most of the glass has a typical late-Roman composition, but some glass fragments are identified as soda ash glass. These are among the earliest medieval ash-fluxed glasses ever found in the Italian peninsula. (C) 2011 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Philosophy; History; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.602
Times cited: 24
DOI: 10.1016/J.JAS.2011.12.031
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Bruijnen Y, Caen JMA, Cagno S, Janssens K, et al. (2012) Getekend Jan R. : Jan Rombouts, een renaissancemeester herontdekt. 207 p
Keywords: ME2 Book as editor or co-editor; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“An N-myristoylated globin with a redox-sensing function that regulates the defecation cycle in Caenorhabditis elegans”. Tilleman L, De Henau S, Pauwels M, Nagy N, Pintelon I, Braeckman BP, De Wael K, Van Doorslaer S, Adriaensen D, Timmermans J-P, Moens L, Dewilde S, PLoS ONE 7, e48768 (2012). http://doi.org/10.1371/JOURNAL.PONE.0048768
Abstract: Globins occur in all kingdoms of life where they fulfill a wide variety of functions. In the past they used to be primarily characterized as oxygen transport/storage proteins, but since the discovery of new members of the globin family like neuroglobin and cytoglobin, more diverse and complex functions have been assigned to this heterogeneous family. Here we propose a function for a membrane-bound globin of C. elegans, GLB-26. This globin was predicted to be myristoylated at its N-terminus, a post-translational modification only recently described in the globin family. In vivo, this globin is found in the membrane of the head mesodermal cell and in the tail stomato-intestinal and anal depressor muscle cells. Since GLB-26 is almost directly oxidized when exposed to oxygen, we postulate a possible function as electron transfer protein. Phenotypical studies show that GLB-26 takes part in regulating the length of the defecation cycle in C. elegans under oxidative stress conditions.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.806
Times cited: 6
DOI: 10.1371/JOURNAL.PONE.0048768
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