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“Plasma modelling and numerical simulation”. van Dijk J, Kroesen GMW, Bogaerts A, Journal of physics: D: applied physics 42, 190301 (2009). http://doi.org/10.1088/0022-3727/42/19/190301
Abstract: Plasma modelling is an exciting subject in which virtually all physical disciplines are represented. Plasma models combine the electromagnetic, statistical and fluid dynamical theories that have their roots in the 19th century with the modern insights concerning the structure of matter that were developed throughout the 20th century. The present cluster issue consists of 20 invited contributions, which are representative of the state of the art in plasma modelling and numerical simulation. These contributions provide an in-depth discussion of the major theories and modelling and simulation strategies, and their applications to contemporary plasma-based technologies. In this editorial review, we introduce and complement those papers by providing a bird's eye perspective on plasma modelling and discussing the historical context in which it has surfaced.
Keywords: Editorial; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 64
DOI: 10.1088/0022-3727/42/19/190301
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“Sputter-deposited Mg-Al-O thin films: linking molecular dynamics simulations to experiments”. Georgieva V, Saraiva M, Jehanathan N, Lebelev OI, Depla D, Bogaerts A, Journal of physics: D: applied physics 42, 065107 (2009). http://doi.org/10.1088/0022-3727/42/6/065107
Abstract: Using a molecular dynamics model the crystallinity of MgxAlyOz thin films with a variation in the stoichiometry of the thin film is studied at operating conditions similar to the experimental operating conditions of a dual magnetron sputter deposition system. The films are deposited on a crystalline or amorphous substrate. The Mg metal content in the film ranged from 100% (i.e. MgO film) to 0% (i.e. Al2O3 film). The radial distribution function and density of the films are calculated. The results are compared with x-ray diffraction and transmission electron microscopy analyses of experimentally deposited thin films by the dual magnetron reactive sputtering process. Both simulation and experimental results show that the structure of the MgAlO film varies from crystalline to amorphous when the Mg concentration decreases. It seems that the crystalline MgAlO films have a MgO structure with Al atoms in between.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 37
DOI: 10.1088/0022-3727/42/6/065107
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“Original close-packed structure and magnetic properties of the Pb4Mn9O20 manganite”. Abakumov AM, Hadermann J, Tsirlin AA, Tan H, Verbeeck J, Zhang H, Dikarev EV, Shpanchenko RV, Antipov EV, Journal of solid state chemistry 182, 2231 (2009). http://doi.org/10.1016/j.jssc.2009.06.003
Abstract: The crystal structure of the Pb4Mn9O20 compound (previously known as Pb0.43MnO2.18) was solved from powder X-ray diffraction, electron diffraction, and high resolution electron microscopy data (S.G. Pnma, a=13.8888(2) Å, b=11.2665(2) Å, c=9.9867(1) Å, RI=0.016, RP=0.047). The structure is based on a 6H (cch)2 close packing of pure oxygen h-type (O16) layers alternating with mixed c-type (Pb4O12) layers. The Mn atoms occupy octahedral interstices formed by the oxygen atoms of the close-packed layers. The MnO6 octahedra share edges within the layers, whereas the octahedra in neighboring layers are linked through corner sharing. The relationship with the closely related Pb3Mn7O15 structure is discussed. Magnetization measurements reveal a peculiar magnetic behavior with a phase transition at 52 K, a small net magnetization below the transition temperature, and a tendency towards spin freezing.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 5
DOI: 10.1016/j.jssc.2009.06.003
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“Synthesis and magnetic properties of rare earth ruthenates, Ln5Ru2O12 (Ln=Pr, Nd, SmTb)”. Bharathy M, Gemmill WR, Fox AH, Darriet J, Smith MD, Hadermann J, Remy MS, zur Loye H-C, Journal of solid state chemistry 182, 1164 (2009). http://doi.org/10.1016/j.jssc.2009.02.013
Abstract: Single crystals of Ln5Ru2O12 (Ln=Pr, Nd, SmTb) were grown out of either NaOH or KOH fluxes in sealed silver tubes. The crystals of all the phases were observed to be twinned as confirmed by TEM studies. The series crystallize in the C2/m monoclinic system with lattice parameters, a=12.4049(4)12.7621(6) Å, b=5.8414(2)5.9488(3) Å, c=7.3489(2)7.6424(4) Å, β=107.425(3)107.432(2)° and Z=2. The crystal structure is isotypic with the defect/disorder model of Ln5Re2O12 (Ln = Y, Gd) and consists of one dimensional edge shared RuO6 octahedral chains separated by a two dimensional LnOx polyhedral framework. Magnetic measurements indicate paramagnetic and antiferromagnetic behavior for Ln=Nd, SmGd and Ln=Tb, respectively.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 4
DOI: 10.1016/j.jssc.2009.02.013
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“Synthesis, crystal structure and magnetic properties of the Sr2Al0.78Mn1.22O5.2 anion-deficient layered perovskite”. d' Hondt H, Hadermann J, Abakumov AM, Kalyuzhnaya AS, Rozova MG, Tsirlin AA, Tan H, Verbeeck J, Antipov EV, Van Tendeloo G, Journal of solid state chemistry 182, 356 (2009). http://doi.org/10.1016/j.jssc.2008.11.002
Abstract: A new layered perovskite Sr2Al0.78Mn1.22O5.2 has been synthesized by solid state reaction in a sealed evacuated silica tube. The crystal structure has been determined using electron diffraction, high-resolution electron microscopy, and high-angle annular dark field imaging and refined from X-ray powder diffraction data (space group P4/mmm, a=3.89023(5) Å, c=7.8034(1) Å, RI=0.023, RP=0.015). The structure is characterized by an alternation of MnO2 and (Al0.78Mn0.22)O1.2 layers. Oxygen atoms and vacancies, as well as the Al and Mn atoms in the (Al0.78Mn0.22)O1.2 layers are disordered. The local atomic arrangement in these layers is suggested to consist of short fragments of brownmillerite-type tetrahedral chains of corner-sharing AlO4 tetrahedra interrupted by MnO6 octahedra, at which the chain fragments rotate over 90°. This results in an averaged tetragonal symmetry. This is confirmed by the valence state of Mn measured by EELS. The relationship between the Sr2Al0.78Mn1.22O5.2 tetragonal perovskite and the parent Sr2Al1.07Mn0.93O5 brownmillerite is discussed. Magnetic susceptibility measurements indicate spin glass behavior of Sr2Al0.78Mn1.22O5.2. The lack of long-range magnetic ordering contrasts with Mn-containing brownmillerites and is likely caused by the frustration of interlayer interactions due to presence of the Mn atoms in the (Al0.78Mn0.22)O1.2 layers.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 12
DOI: 10.1016/j.jssc.2008.11.002
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“EPXMA survey of shelf sediments (Southern Bight, North Sea): a glance beyond the XRD-invisible”. de Maeyer-Worobiec A, Dekov VM, Laane RWPM, Van Grieken R, Microchemical journal 91, 21 (2009). http://doi.org/10.1016/J.MICROC.2008.07.001
Abstract: Shelf sediments of the southern North Sea, were studied with a microanalytical [electron probe X-ray microanalysis (EPXMA)] and two bulk [X-ray diffraction (XRD) and X-ray fluorescence (XRF)] techniques. The investigation proved that the promptness of the microanalytical method is combined with a reasonable analytical reliability. XRD studies of such a type of sediments with monotonous mineral composition are not able to provide mineralogical information beyond the main well-crystalline minerals and the mineralogical quantitative characteristic of the sediment based on XRD estimations are incorrect. The EPXMA mineralogical interpretations are based on the statistical evaluation of a huge data set (thousands of mineral particles) and provide a rather correct quantitative determination of the main minerals. The comparative EPXMAXRF study revealed that the Al, Si, K, Ca, Fe and to some extent Ti contents estimated by EPXMA are fairly reliable. In this respect the accuracy of the EPXMA-based mineral identification of the pure silicates, pure aluminosilicates, and Al-, Ca-, Fe- and Ti-containing minerals with simple composition is very high. Mg-calcite, augite and apatite determinations are assessed to be correct. The supposed accuracy of the clay mineral determinations is slightly lower (7080%) than that of the other main minerals due to the complex and varying composition of the clays. The identification of XRD-invisible accessory minerals and quantification of their presence in the sediments is an essential advantage of the EPXMA, which makes it a useful approach in tracing the origin of the sediments, the pathways of their transport and the geochemical processes they have undergone. However, the EPXMA has several flaws, which need to be solved in the future sediment investigations: (1) calibration with natural standards is needed in order to provide a higher accuracy of the mineral determinations; (2) any EPXMA study of sediments needs to be secured with XRF examinations of selected samples since EPXMA gives only semi-quantitative information about the abundance of the elements; (3) ultra-thin window EPXMA of low-Z elements has to be used since some of them (O, C) are always present in the main sediment components: silicates, aluminosilicates, carbonates and metal oxyhydroxides; (4) the interpretations of the clay fraction have to be supported with detailed XRD investigations of selected samples, while the mineralogy of the silt and sand fractions needs to be backed up with optical microscopy studies. The information from different analytical techniques (EPXMA with XRFXRD-optical microscopy of selected samples) combined with the knowledge about the most possible minerals in a given environment, would give the most reliable results in studying mineralogical composition of shelf sediments.
Keywords: A1 Journal article; Laboratory Experimental Medicine and Pediatrics (LEMP); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.MICROC.2008.07.001
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“Organic surface coating on Coccolithophores –, Emiliania huxleyi: its determination and implication in the marine carbon cycle”. Godoi RHM, Aerts K, Harlay J, Kaegi R, Ro C-U, Chou L, Van Grieken R, Microchemical journal 91, 266 (2009). http://doi.org/10.1016/J.MICROC.2008.12.009
Abstract: Most of the marine precipitation of CaCO3 is due to the biological activities of planktonic and benthic organisms in waters largely oversaturated with respect to calcium carbonates. This saturation state is expected to decrease as CO2 increases in seawater. A conventional view in oceanography suggests that calcium carbonates organisms are preserved in oversaturated waters and dissolve only below the lysocline. However, it has be postulated that a fraction of the CaCO3 precipitated biogenically could dissolve in oversaturated waters due to the formation of microenvironments in which respired CO2 decreases the saturation state of seawater (Ù) in the vicinity of CaCO3 crystals. In the present study, cells of the coccolithophore Emiliania huxleyi obtained from laboratory cultures and field samples collected in the Gulf of Biscay, were examined using variable-energy electron-probe microanalysis, to determine the presence and thickness of their organic coating. In addition, a new approach for transferring micrometer-sized particles from a filter onto transmission electron microscope grids using manipulators was used to investigate individual coccolithophores. The dry thickness of an organic coating over the coccolithophore surface was found to range between 280 and 350 nm. The resemblance of this coating to the carbohydrates produced and released by the cell is discussed as well as their potential for constituting a microenvironment that hosts bacteria. The properties of this organic coating and its role in the preservation/dissolution and export of biogenic carbonates in the water column are one of the major issues of carbonate geochemistry.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.MICROC.2008.12.009
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“Adsorption of small molecules on graphene”. Leenaerts O, Partoens B, Peeters FM, Microelectronics journal 40, 860 (2009). http://doi.org/10.1016/j.mejo.2008.11.022
Abstract: We investigate the adsorption process of small molecules on graphene through first-principles calculations and show the presence of two main charge transfer mechanisms. Which mechanism is the dominant one depends on the magnetic properties of the adsorbing molecules. We explain these mechanisms through the density of states of the system and the molecular orbitals of the adsorbates, and demonstrate the possible difficulties in calculating the charge transfer from first principles between a graphene sheet and a molecule. Our results are in good agreement with experiment.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.163
Times cited: 116
DOI: 10.1016/j.mejo.2008.11.022
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“Dielectric mismatch effect on coupled impurity states in a freestanding nanowire”. Li B, Partoens B, Peeters FM, Magnus W, Microelectronics journal 40, 446 (2009). http://doi.org/10.1016/j.mejo.2008.06.028
Abstract: We studied the coupled impurity states in a freestanding semiconductor nanowire (NW), within the effective mass approximation and including the effect of the dielectric mismatch, by using finite element method. Bonding and anti-bonding states are found and their energies converge with increasing distance di between the two impurities. The dependence of the binding energy on the wire radius R and the distance di between the two impurities is investigated, and we compare it with the result of a freestanding NW that contains a single impurity.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.163
Times cited: 4
DOI: 10.1016/j.mejo.2008.06.028
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“Neutral shallow donors near a metallic interface”. Slachmuylders AF, Partoens B, Magnus W, Peeters FM, Microelectronics journal 40, 753 (2009). http://doi.org/10.1016/j.mejo.2008.11.010
Abstract: The effect of a metallic gate on the bound states of a shallow donor located near the gate is studied. We calculate the energy spectrum as a function of the distance between the metallic gate and the donor and find an anti-crossing behavior in the energy levels for certain distances. We show how a transverse electric field can tune the average position of the electron with respect to the metallic gate and the impurity.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.163
Times cited: 1
DOI: 10.1016/j.mejo.2008.11.010
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“Holstein polarons near surfaces”. Goodvin GL, Covaci L, Berciu M, Physical Review Letters 103, 176402 (2009). http://doi.org/10.1103/PhysRevLett.103.176402
Abstract: We study the effects of a nearby surface on the spectral weight of a Holstein polaron, using the inhomogeneous momentum average approximation which is accurate over the entire range of electron-phonon (e-ph) coupling strengths. The broken translational symmetry is taken into account exactly. We find that the e-ph coupling gives rise to a large additional surface potential, with strong retardation effects, which may bind surface states even when they are not normally expected. The surface, therefore, has a significant effect and bulk properties are recovered only very far away from it. These results demonstrate that interpretation in terms of bulk quantities of spectroscopic data sensitive only to a few surface layers is not always appropriate.
Keywords: A1 Journal article
Impact Factor: 8.462
Times cited: 8
DOI: 10.1103/PhysRevLett.103.176402
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“Polaron formation in the presence of Rashba spin-orbit coupling: implications for spintronics”. Covaci L, Berciu M, Physical Review Letters 102, 186403 (2009). http://doi.org/10.1103/PhysRevLett.102.186403
Abstract: We study the effects of the Rashba spin-orbit coupling on polaron formation, using a suitable generalization of the momentum average approximation. While previous work on a parabolic band model found that spin-orbit coupling increases the effective mass, we show that the opposite holds for a tight-binding model, unless both the spin-orbit and the electron-phonon couplings are weak. It is thus possible to lower the effective mass of the polaron by increasing the spin-orbit coupling. We also show that when the spin-orbit coupling is large as compared to the phonon energy, the polaron retains only one of the spin-polarized bands in its coherent spectrum. This has major implications for the propagation of spin-polarized currents in such materials, and thus for spintronic applications.
Keywords: A1 Journal article
Impact Factor: 8.462
Times cited: 25
DOI: 10.1103/PhysRevLett.102.186403
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“Coherent three-level mixing in an electronic quantum dot”. Payette C, Yu G, Gupta JA, Austing DG, Nair SV, Partoens B, Amaha S, Tarucha S, Physical review letters 102, 026808 (2009). http://doi.org/10.1103/PhysRevLett.102.026808
Abstract: We observe magnetic-field-induced level mixing and quantum superposition phenomena between three approaching single-particle states in a quantum dot probed via the ground state of an adjacent quantum dot by single-electron resonant tunneling. The mixing is attributed to anisotropy and anharmonicity in realistic dot confining potentials. The pronounced anticrossing and transfer of strengths (both enhancement and suppression) between resonances can be understood with a simple coherent level mixing model. Superposition can lead to the formation of a dark state by complete cancellation of an otherwise strong resonance, an effect resembling coherent population trapping in a three-level-system of quantum and atom optics.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 26
DOI: 10.1103/PhysRevLett.102.026808
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“Confinement effects on intermediate-state flux patterns in mesoscopic type-I superconductors”. Berdiyorov GR, Hernandez AD, Peeters FM, Physical review letters 103, 267002 (2009). http://doi.org/10.1103/PhysRevLett.103.267002
Abstract: Intermediate-state flux structures in mesoscopic type-I superconductors are studied within the Ginzburg-Landau theory. In addition to well-established tubular and laminar structures, the strong confinement leads to the formation of (i) a phase of singly quantized vortices, which is typical for type-II superconductors and (ii) a ring of a normal domain at equilibrium. The stability region and the formation process of these intermediate-state structures are strongly influenced by the geometry of the sample.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 28
DOI: 10.1103/PhysRevLett.103.267002
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“Local current injection into mesoscopic superconductors for the manipulation of quantum states”. Milošević, MV, Kanda A, Hatsumi S, Peeters FM, Ootuka Y, Physical review letters 103, 217003 (2009). http://doi.org/10.1103/PhysRevLett.103.217003
Abstract: We perform strategic current injection in a small mesoscopic superconductor and control the (non)equilibrium quantum states in an applied homogeneous magnetic field. In doing so, we realize a current-driven splitting of multiquanta vortices, current-induced transitions between states with different angular momenta, and current-controlled switching between otherwise degenerate quantum states. These fundamental phenomena form the basis for the electronic and logic applications discussed, and are confirmed in both theoretical simulations and multiple-small-tunnel-junction transport measurements.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 48
DOI: 10.1103/PhysRevLett.103.217003
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“Magnetic-field asymmetry of electron wave packet transmission in bent channels capacitively coupled to a metal gate”. Kalina R, Szafran B, Bednarek S, Peeters FM, Physical review letters 102, 066807 (2009). http://doi.org/10.1103/PhysRevLett.102.066807
Abstract: We study the electron wave packet moving through a bent channel. We demonstrate that the packet transmission probability becomes an asymmetric function of the magnetic field when the electron packet is capacitively coupled to a metal plate. The coupling occurs through a nonlinear potential which translates a different kinetics of the transport for opposite magnetic-field orientations into a different potential felt by the scattered electron.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 14
DOI: 10.1103/PhysRevLett.102.066807
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“Unconventional vortex dynamics in mesoscopic superconducting corbino disks”. Lin NS, Misko VR, Peeters FM, Physical review letters 102, 197003 (2009). http://doi.org/10.1103/PhysRevLett.102.197003
Abstract: The discrete shell structure of vortex matter strongly influences the flux dynamics in mesoscopic superconducting Corbino disks. While the dynamical behavior is well understood in large and in very small disks, in the intermediate-size regime it occurs to be much more complex and unusual, due to (in)commensurability between the vortex shells. We demonstrate unconventional vortex dynamics (inversion of shell velocities with respect to the gradient driving force) and angular melting (propagating from the boundary where the shear stress is minimum, towards the center) in mesoscopic Corbino disks.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 18
DOI: 10.1103/PhysRevLett.102.197003
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“Supercooled molecular liquids and the glassy phases of chemically bonded N, P, As, Si and Ge”. Matthai CC, March NH, Lamoen D, Physics and chemistry of liquids 47, 607 (2009). http://doi.org/10.1080/00319100903148553
Abstract: Glassy phases which have insulating character exist for a variety of monatomic species. By contrast, until recently, it has been possible to make bulk metallic glasses (BMG) by vitrification only for multicomponent systems. After a relatively brief summary on supercooling of a few molecular liquids, we review some of the recently reported results on molecular assemblies of the series N, P, As and amorphous Si and Ge. Based on these results, we suggest that the transition metals with their directional bonding might be suitable candidates for the production of BMG by vitrification.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.145
Times cited: 1
DOI: 10.1080/00319100903148553
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“Variation of K X-ray fluorescence cross-sections of Cu, Y and Ba in YBa2Cu3O7-\delta superconductor”. Baltas H, Čevik U, Solid state communications 149, 231 (2009). http://doi.org/10.1016/J.SSC.2008.11.010
Abstract: K X-ray fluorescence cross-sections of Cu, Y and Ba elements were measured in CuO, Y(2)O(3), BaCO(3) Compounds and YBa(2)Cu(3)O(7-delta) superconductor samples (nonreacted agent, calcined and sintered states). A superconductor sample of YBa(2)Cu(3)O(7-delta) was prepared by using a solid-state reaction technique. The samples were excited by gamma rays of energy 59.5 keV from a (241)Am radioisotope source. The Cu, Y and Ba K X-ray intensities counted with a Si(Li) detector were measured in different solid-state conditions. The obtained values of K X-ray fluorescence cross-section were compared with the theoretical values of pure Cu, Y and Ba elements. We found that the K X-ray fluorescence cross-section of Cu, Y and Ba in YBa(2)Cu(3)O(7-delta) sample is changed in different solid-state conditions, depending on the mixture (nonreacted agent), calcined and sintered states. (c) 2008 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.SSC.2008.11.010
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“Effects of nanocracks on the magnetic and electrical properties of La0.8Sr0.2MnO3 single crystals”. Dominiczak M, Ruyter A, Limelette P, Monot-Laffez I, Giovannelli F, Rossell MD, Van Tendeloo G, Solid state communications 149, 1543 (2009). http://doi.org/10.1016/j.ssc.2009.06.001
Abstract: An investigation of the physical properties of La0.8Sr0.2MnO3 single crystals grown by the molten zone technique is realized close to the metal-to-insulator transition temperature (TMI). In this paper, we review the effect of the structural defects through magnetotransport and local magnetic microstructures. From electron microscopy observations, some nanocrack defects (i.e. defects at a nanometer scale) were found, essentially in the center part of the single crystals. At room temperature, magnetic force microscopy measurements have shown that the absence of defects allowed a magnetic ordering of the domains at the crystal edge, which is the best-crystallized region. In addition, the magnetization loops have permitted us to verify that the crystal was ferromagnetically weaker in the center. On analyzing the electrical resistivity data, we observed in the linear current regime a sensitive variation of the resistivity due to defects, by comparing the center and the edge of the material at TMI. Additionally, at strong current, non-linearity phenomena have been supposed to be related to local heating. Finally, we discuss the structural disorder effect on the relaxation of the ferromagnetic domains.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.554
Times cited: 3
DOI: 10.1016/j.ssc.2009.06.001
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“Magneto-ballistic transport through micro-structured junctions on a curved two-dimensional electron gas”. Papp G, Peeters FM, Solid state communications 149, 778 (2009). http://doi.org/10.1016/j.ssc.2009.02.033
Abstract: We investigate theoretically the ballistic transport in a two-dimensional electron gas, which is rolled up as a tube and is micro-structured into a Hall bar. A uniform magnetic field applied to such a curved surface results in a non-uniform perpendicular magnetic field. The bend resistances become asymmetric with respect to the orientation of the magnetic field due to the varying magnetic field along the junction. The resistance asymmetry is strongly affected by corrugation due to the varying mobility along different crystallographic directions. We compare our results with a recent transport measurement.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.554
Times cited: 1
DOI: 10.1016/j.ssc.2009.02.033
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“Single-run ion chromatographic separation of inorganic and low-molecular-mass organic anions under isocratic elution: application to environmental samples”. Krata A, Kontozova-Deutsch V, Bencs L, Deutsch F, Van Grieken R, Talanta : the international journal of pure and applied analytical chemistry 79, 16 (2009). http://doi.org/10.1016/J.TALANTA.2009.02.044
Abstract: For the isocratic ion chromatography (IC) separation of low-molecular-mass organic acids and inorganic anions three different anion-exchange columns were studied: IonPac AS14 (9 ìm particle size), Allsep A-2 (7 ìm particle size), and IC SI-50 4E (5 ìm particle size). A complete baseline separation for all analyzed anions (i.e., F−, acetate, formate, Cl−, NO2−, Br−, NO3−, HPO42− and SO42−) in one analytical cycle of shorter than 17 min was achieved on the IC SI-50 4E column, using an eluent mixture of 3.2 mM Na2CO3 and 1.0 mM NaHCO3 with a flow rate of 1.0 mL min−1. On the IonPac AS14 column, it was possible to separate acetate from inorganic anions in one run (i.e., less than 9 min), but not formate, under the following conditions: 3.5 mM Na2CO3 plus 1.0 mM NaHCO3 with a flow rate of 1.2 mL min−1. Therefore, it was necessary to adapt a second run with a 2.0 mM Na2B4O7 solution as an eluent under a flow rate of 0.8 mL min−1 for the separation of organic ions, which considerably enlarged the analysis time. For the Allsep A-2 column, using an eluent mixture of 1.2 mM Na2CO3 plus 1.5 mM NaHCO3 with a flow rate of 1.6 mL min−1, it was possible to separate almost all anions in one run within 25 min, except the fluoride-acetate critical pair. A Certified Multianion Standard Solution PRIMUS for IC was used for the validation of the analytical methods. The lowest RSDs (less than 1%) and the best LODs (0.02, 0.2, 0.16, 0.11, 0.06, 0.05, 0.04, 0.14 and 0.09 mg L−1 for F−, Ac−, For−, Cl−, NO2−, Br−, NO3−, HPO42− and SO42−, respectively) were achieved using the IC SI-50 4E column. This column was applied for the separation of concerned ions in environmental precipitation samples such as snow, hail and rainwater.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.TALANTA.2009.02.044
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“Estimation of ecotoxicity of petroleum hydrocarbon mixtures in soil based on HPLC-GCXGC analysis”. Mao D, Lookman R, van de Weghe H, Weltens R, Vanermen G, Brucker N, Diels L, Chemosphere 77, 1508 (2009). http://doi.org/10.1016/J.CHEMOSPHERE.2009.10.004
Abstract: Detailed HPLCGCXGC/FID (high performance liquid chromatography followed by comprehensive two-dimensional gas chromatography with flame-ionization detection) analysis of oil-contaminated soils was performed to interpret results of selected acute ecotoxicity assays. For the five ecotoxicity assays tested, plant seed germination and Microtox® were selected as most sensitive for evaluating ecotoxicity of the oil in the soil phase and in the leaching water, respectively. The measured toxicity for cress when testing the soil samples did not correspond to TPH concentration in the soil. A detailed chemical composition analysis of the oil contamination using HPLCGCXGC/FID allows to better predict the ecotoxicological risk and leaching potential of petroleum hydrocarbons in soil. Cress biomass production per plant was well correlated to the total aromatic hydrocarbon concentration (R2 = 0.79, n = 6), while cress seed germination was correlated (R2 = 0.82, n = 6) with total concentration of highly water-soluble aromatic hydrocarbons (HSaromatics). The observed ecotoxicity of the leaching water for Microtox-bacteria related well to calculated (based on the HPLCGCXGC/FID results) petroleum hydrocarbon equilibrium concentrations in water.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.CHEMOSPHERE.2009.10.004
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“Exposure assessment of a cyclist to PM10 and ultrafine particles”. Berghmans P, Bleux N, Int Panis L, Mishra VK, Torfs R, Van Poppel M, The science of the total environment 407, 1286 (2009). http://doi.org/10.1016/J.SCITOTENV.2008.10.041
Abstract: Estimating personal exposure to air pollution is a crucial component in identifying high-risk populations and situations. It will enable policy makers to determine efficient control strategies. Cycling is again becoming a favorite mode of transport both in developing and in developed countries due to increasing traffic congestion and environmental concerns. in Europe, it is also seen as a healthy sports activity. However, due to high levels of hazardous pollutants in the present day road microenvironment the cyclist might be at a higher health risk due to higher breathing rate and proximity to the vehicular exhaust. In this paper we present estimates of the exposure of a cyclist to particles of various size fractions including ultrafine particles (UFP) in the town of Mol (Flanders, Belgium). The results indicate relatively higher UFP concentration exposure during morning office hours and moderate UFP levels during afternoon. The major sources of UFP and PM(10) were identified, which are vehicular emission and construction activities, respectively. We also present a dust mapping technique which can be a useful tool for town planners and local policy makers. (C) 2008 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.SCITOTENV.2008.10.041
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“Particulate matter and gaseous pollutants in residences in Antwerp, Belgium”. Stranger M, Potgieter-Vermaak SS, Van Grieken R, The science of the total environment 407, 1182 (2009). http://doi.org/10.1016/J.SCITOTENV.2008.10.019
Abstract: This comprehensive study, a first in Flanders, Belgium, aimed at characterizing the residential indoor air quality of subgroups that took part in the European Community Respiratory Health Survey (ECRHS I1991 and ECHRS II1996) questionnaire-based asthma and related illnesses studies. This pilot study aimed at the evaluation of particulate matter and various inorganic gaseous compounds in residences in Antwerp. In addition personal exposure to the gaseous compounds of one individual per residence was assessed. The main objective was to obtain some base-line pollutant levels and compare these with studies performed in other cities, to estimate the indoor air quality in residences in Antwerp. Correlations between the various pollutant levels, indoor:outdoor ratios and the micro-environments of each residence were investigated. This paper presents results on indoor and ambient PM1, PM2.5 and PM10 mass concentrations, its elemental composition in terms of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Pb, Al, Si, S and Cl and the water-soluble ionic concentrations in terms of SO42−, NO32−, Cl−, NH4+ K+, Ca2+. In addition, indoor, ambient and personal exposure levels of the gases NO2, SO2, and O3 were determined. Elevated indoor:outdoor ratios were found for NO2 in residences containing gas stoves. In smoker's houses increased PM concentrations of 58 and 43% were found for the fine and coarse fractions respectively. Contrary to the fact that all I/O ratios of the registered elements in each individual house were significantly correlated to each other, no correlation could be established between the I/O ratios of the different houses, thus indicating a unique micro-environment for each residence. Linear relationships between the particulate matter elemental composition, SO2 and O3 levels indoors and outdoors could be established. No linear relationships between indoor and outdoor NO2 and particulate mass concentrations were found.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.SCITOTENV.2008.10.019
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“Tracing the metal pollution history of the Tisza River through the analysis of a sediment depth profile”. Nguyen HL, Braun M, Szaloki I, Baeyens W, Van Grieken R, Leermakers M, Water, air and soil pollution 200, 119 (2009). http://doi.org/10.1007/S11270-008-9898-2
Abstract: The vertical profiles of 20 major and trace metals were investigated along a 180-cm-long sediment core, which was sampled at Kiss-Janosne-Holt Tisza, an oxbow lake located in the upper part of the Tisza River in Hungary. The vertical profiles showed sharp peaks at different depths, reflecting historical pollution events and unusual changes of river water characteristics. Five different groups of metals, containing metals which were strongly correlated and showing a similar behaviour, could be distinguished by factor analysis. Six areas, with variable degrees and types of contamination, were classified in the sediment core with cluster analysis. The most polluted sections were found in the upper 50-cm part (significantly contaminated by Cu, Zn, Pb, Cd and Hg) and the deeper 100120-cm part (characterised by high concentrations of metals associated with mining activities, such as Fe and Mn, as well as Cu, Zn and Pb). In recent years, important pollution events, such as the one which took place in March of 2000, were the reason for pollution of the upper sediment layers, whereas mining activities during the last century were responsible for the pollution of the deeper core sections.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S11270-008-9898-2
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“Hepatocellular transport and gastrointestinal absorption of lanthanum in chronic renal failure”. Bervoets ARJ, Behets GJ, Schryvers D, Roels F, Yang Z, Verberckmoes SC, Damment SJP, Dauwe S, Mubiana VK, Blust R, de Broe ME, d' Haese PC, Kidney international 75, 389 (2009). http://doi.org/10.1038/ki.2008.571
Abstract: Lanthanum carbonate is a new phosphate binder that is poorly absorbed from the gastrointestinal tract and eliminated largely by the liver. After oral treatment, we and others had noticed 23 fold higher lanthanum levels in the livers of rats with chronic renal failure compared to rats with normal renal function. Here we studied the kinetics and tissue distribution, absorption, and subcellular localization of lanthanum in the liver using transmission electron microscopy, electron energy loss spectrometry, and X-ray fluoresence. We found that in the liver lanthanum was located in lysosomes and in the biliary canal but not in any other cellular organelles. This suggests that lanthanum is transported and eliminated by the liver via a transcellular, endosomal-lysosomal-biliary canicular transport route. Feeding rats with chronic renal failure orally with lanthanum resulted in a doubling of the liver levels compared to rats with normal renal function, but the serum levels were similar in both animal groups. These levels plateaued after 6 weeks at a concentration below 3 g/g in both groups. When lanthanum was administered intravenously, thereby bypassing the gastrointestinal tract-portal vein pathway, no difference in liver levels was found between rats with and without renal failure. This suggests that there is an increased gastrointestinal permeability or absorption of oral lanthanum in uremia. Lanthanum levels in the brain and heart fluctuated near its detection limit with long-term treatment (20 weeks) having no effect on organ weight, liver enzyme activities, or liver histology. We suggest that the kinetics of lanthanum in the liver are consistent with a transcellular transport pathway, with higher levels in the liver of uremic rats due to higher intestinal absorption.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Pathophysiology
Impact Factor: 8.395
Times cited: 29
DOI: 10.1038/ki.2008.571
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“Associations between PM2.5 and heart rate variability are modified by particle composition and beta-blocker use in patients with coronary heart disease”. de Hartog JJ, Lanki T, Timonen KL, Hoek G, Janssen NAH, Ibald-Mulli A, Peters A, Heinrich J, Tarkainen TH, Van Grieken R, van Wijnen JH, Brunekreef B, Pekkanen J, Environmental health perspectives 117, 105 (2009). http://doi.org/10.1289/EHP.11062
Abstract: Background: It has been hypothesized that ambient particulate air pollution is able to modify the autonomic nervous control of the heart, measured as heart rate variability (HRV) . Previously we reported heterogeneous associations between particulate matter with aerodynamic diameter < 2.5 µm (PM2.5) and HRV across three study centers. Objective: We evaluated whether exposure misclassification, effect modification by medication, or differences in particle composition could explain the inconsistencies. Methods: Subjects with coronary heart disease visited clinics biweekly in Amsterdam, the Netherlands ; Erfurt, Germany ; and Helsinki, Finland for 68 months. The standard deviation (SD) of NN intervals on an electrocardiogram (ECG ; SDNN) and high frequency (HF) power of HRV was measured with ambulatory ECG during paced breathing. Outdoor levels of PM2.5 were measured at a central site. In Amsterdam and Helsinki, indoor and personal PM2.5 were measured during the 24 hr preceding the clinic visit. PM2.5 was apportioned between sources using principal component analyses. We analyzed associations of indoor/personal PM2.5, elements of PM2.5, and source-specific PM2.5 with HRV using linear regression. Results: Indoor and personal PM2.5 were not associated with HRV. Increased outdoor PM2.5 was associated with decreased SDNN and HF at lags of 2 and 3 days only among persons not using beta-blocker medication. Traffic-related PM2.5 was associated with decreased SDNN, and long-range transported PM2.5 with decreased SDNN and HF, most strongly among persons not using beta blockers. Indicators for PM2.5 from traffic and long-range transport were also associated with decreased HRV. Conclusions: Our results suggest that differences in the composition of particles, beta-blocker use, and obesity of study subjects may explain some inconsistencies among previous studies on HRV.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1289/EHP.11062
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“In situ study of ballast tank corrosion on ships: part 1”. Verstraelen H, de Baere K, Schillemans W, Lemmens L, Dewil R, Lenaerts S, Potters G, Materials performance 48, 48 (2009)
Keywords: A1 Journal article; Engineering sciences. Technology; Theory of quantum systems and complex systems; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 0.149
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“In situ study of ballast tank corrosion on ships: part 2”. Verstraelen H, de Baere K, Schillemans W, Lemmens L, Dewil R, Lenaerts S, Potters G, Materials performance 48, 54 (2009)
Abstract: A study was undertaken to determine causes and effects of corrosion processes in ballast tanks. Part 1 of this article (October 2009 MP) described the data collection. Part 2 describes the development of a corrosion index (CI) derived from the general International Association of Classification Societies corrosion assessment methods. The CI can be used in situ to assess ballast tank corrosion. An average timeline for-corrosion of tanks is presented.
Keywords: A1 Journal article; Engineering sciences. Technology; Theory of quantum systems and complex systems; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 0.149
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