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Author Pilehvar, S.; Mehta, J.; Dardenne, F.; Robbens, J.; Blust, R.; De Wael, K.
Title (down) Aptasensing of chloramphenicol in the presence of its analogues : reaching the maximum residue limit Type A1 Journal article
Year 2012 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 84 Issue 15 Pages 6753-6758
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000307159200069 Publication Date 2012-06-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 68 Open Access
Notes ; ; Approved Most recent IF: 6.32; 2012 IF: 5.695
Call Number UA @ admin @ c:irua:98816 Serial 5477
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Author Casavola, M.; van Huis, M.A.; Bals, S.; Lambert, K.; Hens, Z.; Vanmaekelbergh, D.
Title (down) Anisotropic cation exchange in PbSe/CdSe core/shell nanocrystals of different geometry Type A1 Journal article
Year 2012 Publication Chemistry of materials Abbreviated Journal Chem Mater
Volume 24 Issue 2 Pages 294-302
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We present a study of Cd2+-for-Pb2+ exchange in PbSe nanocrystals (NCs) with cube, star, and rod shapes. Prolonged temperature-activated cation exchange results in PbSe/CdSe heterostructured nanocrystals (HNCs) that preserve their specific overall shape, whereas the PbSe core is strongly faceted with dominance of {111} facets. Hence, cation exchange proceeds while the Se anion lattice is preserved, and well-defined {111}/{111} PbSe/CdSe interfaces develop. Interestingly, by quenching the reaction at different stages of the cation exchange new structures have been isolated, such as coreshell nanorods, CdSe rods that contain one or two separated PbSe dots and fully zinc blende CdSe nanorods. The crystallographically anisotropic cation exchange has been characterized by a combined HRTEM/HAADF-STEM study of heterointerface evolution over reaction time and temperature. Strikingly, Pb and Cd are only intermixed at the PbSe/CdSe interface. We propose a plausible model for the cation exchange based on a layer-by-layer replacement of Pb2+ by Cd2+ enabled by a vacancy-assisted cation migration mechanism.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000299367500008 Publication Date 2011-11-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0897-4756;1520-5002; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 9.466 Times cited 136 Open Access
Notes Esteem 026019 Approved Most recent IF: 9.466; 2012 IF: 8.238
Call Number UA @ lucian @ c:irua:94211 Serial 124
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Author Lu, Y.-G.; Verbeeck, J.; Turner, S.; Hardy, A.; Janssens, S.D.; De Dobbelaere, C.; Wagner, P.; Van Bael, M.K.; Van Tendeloo, G.
Title (down) Analytical TEM study of CVD diamond growth on TiO2 sol-gel layers Type A1 Journal article
Year 2012 Publication Diamond and related materials Abbreviated Journal Diam Relat Mater
Volume 23 Issue Pages 93-99
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The early growth stages of chemical vapor deposition (CVD) diamond on a solgel TiO2 film with buried ultra dispersed diamond seeds (UDD) have been studied. In order to investigate the diamond growth mechanism and understand the role of the TiO2 layer in the growth process, high resolution transmission electron microscopy (HRTEM), energy-filtered TEM and electron energy loss spectroscopy (EELS) techniques were applied to cross sectional diamond film samples. We find evidence for the formation of TiC crystallites inside the TiO2 layer at different diamond growth stages. However, there is no evidence that diamond nucleation starts from these crystallites. Carbon diffusion into the TiO2 layer and the chemical bonding state of carbon (sp2/sp3) were both extensively investigated. We provide evidence that carbon diffuses through the TiO2 layer and that the diamond seeds partially convert to amorphous carbon during growth. This carbon diffusion and diamond to amorphous carbon conversion make the seed areas below the TiO2 layer grow and bend the TiO2 layer upwards to form the nucleation center of the diamond film. In some of the protuberances a core of diamond seed remains, covered by amorphous carbon. It is however unlikely that the remaining seeds are still active during the growth process.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000302887600017 Publication Date 2012-01-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0925-9635; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.561 Times cited 16 Open Access
Notes Iap; Esteem 026019; Fwo Approved Most recent IF: 2.561; 2012 IF: 1.709
Call Number UA @ lucian @ c:irua:95037UA @ admin @ c:irua:95037 Serial 111
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Author Margui, E.; Hidalgo, M.; Queralt, I.; van Meel, K.; Fontas, C.
Title (down) Analytical capabilities of laboratory, benchtop and handheld X-ray fluorescence systems for detection of metals in aqueous samples pre-concentrated with solid-phase extraction disks Type A1 Journal article
Year 2012 Publication Spectrochimica acta: part B : atomic spectroscopy Abbreviated Journal
Volume 67 Issue Pages 17-23
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract We aimed to achieve improved instrumental sensitivity and detection limits for the analysis of several elements (Cu, Ni, Zn, Pb and Cd) in aqueous samples with energy dispersive X-ray fluorescence spectrometry (EDXRF). The metals were pre-concentrated from aqueous solutions using commercially available organic-based solid-phase extraction (SPE) disks functionalized with iminodiacetate groups. These thin-layer organic materials provide an ideal support for XRF analysis. The elements were collected on the SPE extraction disks using a simple filtration procedure (starting with 1 L of aqueous sample) that allows direct XRF measurements to be performed in the field (in situ). We evaluated the analytical possibilities and drawbacks of using this pre-concentration procedure in combination with the following XRF configurations: a handheld unit, a benchtop EDXRF system and a high-energy polarized-beam EDXRF instrument (HE-P-EDXRF). Using the HE-P-EDXRF system, the detection limits for all metals were more than one order of magnitude lower than those attained using handheld and benchtop EDXRF instrumentation. For the detection of metal concentrations higher than similar to 20 mu g/L, however, handheld or benchtop systems remain a very good option due to their extreme simplicity of operation and low-cost, compact design. We demonstrate the application of these methodologies, using the three equipment systems, to the analysis of trace concentrations of metals in different types of aqueous samples, including tap water and waste water. (C) 2011 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000302757200003 Publication Date 2011-12-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0584-8547; 1873-3565 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:98338 Serial 7454
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Author Zhao, H.J.; Misko, V.R.; Peeters, F.M.
Title (down) Analysis of pattern formation in systems with competing range interactions Type A1 Journal article
Year 2012 Publication New journal of physics Abbreviated Journal New J Phys
Volume 14 Issue Pages 063032
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We analyzed pattern formation and identified various morphologies in a system of particles interacting through a non-monotonic potential with a competing range interaction characterized by a repulsive core (r < r(c)) and an attractive tail (r > r(c)), using molecular-dynamics simulations. Depending on parameters, the interaction potential models the inter-particle interaction in various physical systems ranging from atoms, molecules and colloids to vortices in low kappa type-II superconductors and in recently discovered 'type-1.5' superconductors. We constructed a 'morphology diagram' in the plane 'critical radius r(c)-density n' and proposed a new approach to characterizing the different types of patterns. Namely, we elaborated a set of quantitative criteria in order to identify the different pattern types, using the radial distribution function (RDF), the local density function and the occupation factor.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000306946600003 Publication Date 2012-06-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1367-2630; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.786 Times cited 45 Open Access
Notes ; We acknowledge useful discussions with Ernst Helmut Brandt, Charles Reichhardt and Cynthia Olson Reichhardt. This work was supported by the 'Odysseus' Program of the Flemish Government and the Flemish Science Foundation (FWO-Vl). ; Approved Most recent IF: 3.786; 2012 IF: 4.063
Call Number UA @ lucian @ c:irua:101140 Serial 102
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Author Tilleman, L.; De Henau, S.; Pauwels, M.; Nagy, N.; Pintelon, I.; Braeckman, B.P.; De Wael, K.; Van Doorslaer, S.; Adriaensen, D.; Timmermans, J.-P.; Moens, L.; Dewilde, S.
Title (down) An N-myristoylated globin with a redox-sensing function that regulates the defecation cycle in Caenorhabditis elegans Type A1 Journal article
Year 2012 Publication PLoS ONE Abbreviated Journal Plos One
Volume 7 Issue 12 Pages e48768-9
Keywords A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000313236200008 Publication Date 2012-12-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.806 Times cited 6 Open Access
Notes ; SDH is a Ph.D. fellow of the Fund for Scientific Research (FWO). Financial support to SD and LM was provided by the University of Antwerp (BOF UA TOP 2006) and to SD, LM, BPB, by FWO project G.0247.09. The UltraVIEW VoX spinning disk confocal microscope was purchased with support of the Hercules Foundation (Hercules Type 1: AUHA 09/001). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. ; Approved Most recent IF: 2.806; 2012 IF: 3.730
Call Number UA @ admin @ c:irua:102591 Serial 5741
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Author Aerts, R.; Tu, X.; De Bie, C.; Whitehead, J.C.; Bogaerts, A.
Title (down) An investigation into the dominant reactions for ethylene destruction in non-thermal atmospheric plasmas Type A1 Journal article
Year 2012 Publication Plasma processes and polymers Abbreviated Journal Plasma Process Polym
Volume 9 Issue 10 Pages 994-1000
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract A crucial step, which is still not well understood in the destruction of volatile organic compounds (VOCs) with low temperature plasmas, is the initiation of the process. Here, we present a kinetic model for the destruction of ethylene in low temperature plasmas that allows us to calculate the relative importance of all plasma species and their related reactions. Modifying the ethylene concentration and/or the SED had a major impact on the relative importance of the radicals (i.e., mainly atomic oxygen) and the metastable nitrogen (i.e., more specifically N2(equation image)) in the destruction process. Our results show that the direct destruction by electron impact reactions for ethylene can be neglected; however, we can certainly not neglect the influence of N2(equation image)).
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000309750300008 Publication Date 2012-07-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1612-8850; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.846 Times cited 46 Open Access
Notes Approved Most recent IF: 2.846; 2012 IF: 3.730
Call Number UA @ lucian @ c:irua:101765 Serial 1727
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Author Li, B.
Title (down) Aharonov-Bohm effect in semiconductor quantum rings Type Doctoral thesis
Year 2012 Publication Abbreviated Journal
Volume Issue Pages
Keywords Doctoral thesis; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Antwerpen Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:99488 Serial 85
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Author Wang, B.; Idrissi, H.; Galceran, M.; Colla, M.S.; Turner, S.; Hui, S.; Raskin, J.P.; Pardoen, T.; Godet, S.; Schryvers, D.
Title (down) Advanced TEM investigation of the plasticity mechanisms in nanocrystalline freestanding palladium films with nanoscale twins Type A1 Journal article
Year 2012 Publication International journal of plasticity Abbreviated Journal Int J Plasticity
Volume 37 Issue Pages 140-156
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Nanocrystalline palladium thin films deposited by electron-beam evaporation and deformed by on-chip tensile testing reveal a surprisingly large strain hardening capacity when considering the small similar to 25 nm grain size. The as-grown films contain several coherent single and multifold twin boundaries. The coherency of the twin boundaries considerably decreases with deformation due to dislocation/twin boundary interactions. These reactions are described based on a detailed analysis of the number and the type of dislocations located at the twin boundaries using high-resolution TEM, including aberration corrected microscopy. Sessile Frank dislocations were observed at the twin/matrix interfaces, explaining the loss of the TB coherency due to the Burgers vector pointing out of the twinning plane. Grain boundary mediated processes were excluded as a mechanism dominating the plastic deformation based on the investigation of the grain size distribution as well as the crystallographic texture using Automated Crystallographic Orientation Indexation TEM. Other factors influencing the plastic deformation such as impurities and the presence of a native passivation oxide layer at the surface of the films were investigated using analytical TEM. The twin boundaries observed in the present work partly explain the high strain hardening capacity by providing both increasing resistance to dislocation motion with deformation and a source for dislocation multiplication. (C) 2012 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000307416100009 Publication Date 2012-05-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0749-6419; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.702 Times cited 44 Open Access
Notes Iap; Fwo Approved Most recent IF: 5.702; 2012 IF: 4.356
Call Number UA @ lucian @ c:irua:101082 Serial 74
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Author Van Tendeloo, G.; Bals, S.; Van Aert, S.; Verbeeck, J.; van Dyck, D.
Title (down) Advanced electron microscopy for advanced materials Type A1 Journal article
Year 2012 Publication Advanced materials Abbreviated Journal Adv Mater
Volume 24 Issue 42 Pages 5655-5675
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Vision lab
Abstract The idea of this Review is to introduce newly developed possibilities of advanced electron microscopy to the materials science community. Over the last decade, electron microscopy has evolved into a full analytical tool, able to provide atomic scale information on the position, nature, and even the valency atoms. This information is classically obtained in two dimensions (2D), but can now also be obtained in 3D. We show examples of applications in the field of nanoparticles and interfaces.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000310602200001 Publication Date 2012-08-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0935-9648; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 19.791 Times cited 107 Open Access
Notes This work was supported by funding from the European Research Council under the 7th Framework Program (FP7), ERC grant No 246791 – COUNTATOMS. J.V. Acknowledges funding from the European Research Council under the 7th Framework Program (FP7), ERC Starting Grant 278510 VORTEX. The authors gratefully acknowledge funding from the Research Foundation Flanders (FWO, Belgium). The Qu-Ant-EM microscope was partly funded by the Hercules Fund from the Flemish Government. We thank Rafal Dunin-Borkowski for providing Figure 5d. The authors would like to thank the colleagues who have contributed to this work over the years, including K.J. Batenburg, R. Erni, B. Goris, F. Leroux, H. Lichte, A. Lubk, B. Partoens, M. D. Rossell, P. Schattschneider, B. Schoeters, D. Schryvers, H. Tan, H. Tian, S. Turner, M. van Huis. ECASJO_; Approved Most recent IF: 19.791; 2012 IF: 14.829
Call Number UA @ lucian @ c:irua:100470UA @ admin @ c:irua:100470 Serial 70
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Author Jacobs, L.; Buczyńska, A.; Walgraeve, C.; Potgieter-Vermaak, S.; Van Grieken, R.; et al.
Title (down) Acute changes in pulse pressure in relation to constituents of particulate air pollution in elderly persons Type A1 Journal article
Year 2012 Publication Environmental research Abbreviated Journal
Volume 117 Issue Pages 60-67
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract An increased pulse pressure (difference between systolic and diastolic blood pressure) suggests aortic stiffening. The objective of this study was to examine the acute effects of both particulate matter (PM) mass and composition on blood pressure, among elderly persons. We carried out a panel study in persons living in elderly homes in Antwerp, Belgium. We recruited 88 non-smoking persons, 70% women with a mean age of 83 years (standard deviation: 5.2). Blood pressure was measured and a blood sample was collected on two time points, which were chosen so that there was an exposure contrast in ambient PM exposure. The elemental content of the collected indoor and outdoor PM2.5 (particulate matter with an aerodynamic diameter <2.5 μm) mass concentration was measured. Oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) on outdoor PM10 (particulate matter with an aerodynamic diameter <10 μm) were measured. Each interquartile range increase of 20.8 μg/m³ in 24-h mean outdoor PM2.5 was associated with an increase in pulse pressure of 4.0 mmHg (95% confidence interval: 1.86.2), in persons taking antihypertensive medication (n=57), but not in persons not using antihypertensive medication (n=31) (p for interaction: 0.02). Vanadium, iron and nickel contents of PM2.5 were significantly associated with systolic blood pressure and pulse pressure, among persons on antihypertensive medication. Similar results were found for indoor concentrations. Of the oxy-PAHs, chrysene-5,6-dione and benzo[a]pyrene-3,6-dione were significantly associated with increases in systolic blood pressure and pulse pressure. In elderly, pulse pressure was positively associated with acute increases in outdoor and indoor air pollution, among persons taking antihypertensive medication. These results might form a mechanistic pathway linking air pollution as a trigger of cardiovascular events.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000307912900008 Publication Date 2012-06-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0013-9351; 1096-0953 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:102569 Serial 7418
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Author Roelandts, T.; Batenburg, K.J.; Biermans, E.; Kübel, C.; Bals, S.; Sijbers, J.
Title (down) Accurate segmentation of dense nanoparticles by partially discrete electron tomography Type A1 Journal article
Year 2012 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 114 Issue Pages 96-105
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Accurate segmentation of nanoparticles within various matrix materials is a difficult problem in electron tomography. Due to artifacts related to image series acquisition and reconstruction, global thresholding of reconstructions computed by established algorithms, such as weighted backprojection or SIRT, may result in unreliable and subjective segmentations. In this paper, we introduce the Partially Discrete Algebraic Reconstruction Technique (PDART) for computing accurate segmentations of dense nanoparticles of constant composition. The particles are segmented directly by the reconstruction algorithm, while the surrounding regions are reconstructed using continuously varying gray levels. As no properties are assumed for the other compositions of the sample, the technique can be applied to any sample where dense nanoparticles must be segmented, regardless of the surrounding compositions. For both experimental and simulated data, it is shown that PDART yields significantly more accurate segmentations than those obtained by optimal global thresholding of the SIRT reconstruction.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000301954300011 Publication Date 2012-01-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 34 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:97710 Serial 52
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Author Ramezanipour, F.; Greedan, J.E.; Siewenie, J.; Donaberger, R.L.; Turner, S.; Botton, G.A.
Title (down) A vacancy-disordered, oxygen-deficient perovskite with long-range magnetic ordering : local and average structures and magnetic properties of Sr2Fe1.5Cr0.5O5 Type A1 Journal article
Year 2012 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
Volume 51 Issue 4 Pages 2638-2644
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The local and average crystal structures and magnetic properties of the oxygen-deficient perovskite Sr2Fe1.5Cr0.5O5+y were studied using powder X-ray and neutron diffraction, neutron-pair distribution function analysis, and electron energy-loss spectroscopy. This material crystallizes in the cubic Pm3̅m space group, with a = 3.94491(14) Å. The oxygen vacancies are distributed randomly throughout the perovskite-type structure, and the average coordination number of the Fe(Cr) sites is 5. Refinement of the neutron diffraction data indicates y 0.05. This is in discordance with an earlier report on a material with the same nominal composition and cell constant. Electron energy-loss Cr L2,3-edge spectroscopy shows that Cr3+ is present, which is also contrary to previous speculation. Neutron-pair distribution function studies show that a brownmillerite-like model involving ordered vacancies and alternating octahedral and tetrahedral coordination at the metal sites, gives a better description of the local structure out to 5 Å. A remarkable phenomenon determined by neutron diffraction in Sr2Fe1.5Cr0.5O5 is the occurrence of a long-range G-type antiferromagnetic ordering with Tc ≈ 565 K because cubic oxygen-deficient perovskites with B-site disorder usually do not undergo transitions to magnetically ordered states. The observation of long-range antiferromagnetic order and the Tc value are in accordance with previous Mössbauer spectroscopic studies.
Address
Corporate Author Thesis
Publisher Place of Publication Easton, Pa Editor
Language Wos 000300466300079 Publication Date 2012-01-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-1669;1520-510X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.857 Times cited 12 Open Access
Notes Fwo Approved Most recent IF: 4.857; 2012 IF: 4.593
Call Number UA @ lucian @ c:irua:95039 Serial 3828
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Author Quintana, M.; Grzelczak, M.; Spyrou, K.; Calvaresi, M.; Bals, S.; Kooi, B.; Van Tendeloo, G.; Rudolf, P.; Zerbetto, F.; Prato, M.
Title (down) A simple road for the transformation of few-layer graphene into MWNTs Type A1 Journal article
Year 2012 Publication Journal of the American Chemical Society Abbreviated Journal J Am Chem Soc
Volume 134 Issue 32 Pages 13310-13315
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We report the direct formation of multiwalled carbon nanotubes (MWNT) by ultrasonication of graphite in dimethylformamide (DMF) upon addition of ferrocene aldehyde (Fc-CHO). The tubular structures appear exclusively at the edges of graphene layers and contain Fe clusters. Pc in conjunction with benzyl aldehyde, or other Fc derivatives, does not induce formation of NT. Higher amounts of Fc-CHO added to the dispersion do not increase significantly MWNT formation. Increasing the temperature reduces the amount of formation of MWNTs and shows the key role of ultrasound-induced cavitation energy. It is concluded that Fc-CHO first reduces the concentration of radical reactive species that slice graphene into small moieties, localizes itself at the edges of graphene, templates the rolling up of a sheet to form a nanoscroll, where it remains trapped, and finally accepts and donates unpaired electron to the graphene edges and converts the less stable scroll into a MWNT. This new methodology matches the long held notion that CNTs are rolled up graphene layers. The proposed mechanism is general and will lead to control the production of carbon nanostructures by simple ultrasonication treatments.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000307487200034 Publication Date 2012-05-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-7863;1520-5126; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.858 Times cited 56 Open Access
Notes This work was supported by the University of Trieste, the Italian Ministry of Education MIUR (cofin Prot. 20085M27SS), the European Union through the ERC grant No. 246791 – COUNTATOMS, the grant agreement for an Integrated Infrastructure Initiative N. 262348 ESMI, and the “Graphene-based electronics” research program of the Foundation for Fundamental Research on Matter (FOM). Approved Most recent IF: 13.858; 2012 IF: 10.677
Call Number UA @ lucian @ c:irua:101109 Serial 3003
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Author Li, M.R.; Adem, U.; McMitchell, S.R.C.; Xu, Z.; Thomas, C.I.; Warren, J.E.; Giap, D.V.; Niu, H.; Wan, X.; Palgrave, R.G.; Schiffmann, F.; Cora, F.; Slater, B.; Burnett, T.L.; Cain, M.G.; Abakumov, A.M.; Van Tendeloo, G.; Thomas, M.F.; Rosseinsky, M.J.; Claridge, J.B.;
Title (down) A polar corundum oxide displaying weak ferromagnetism at room temperature Type A1 Journal article
Year 2012 Publication Journal of the American Chemical Society Abbreviated Journal J Am Chem Soc
Volume 134 Issue 8 Pages 3737-3747
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Combining long-range magnetic order with polarity in the same structure is a prerequisite for the design of (magnetoelectric) multiferroic materials. There are now several demonstrated strategies to achieve this goal, but retaining magnetic order above room temperature remains a difficult target. Iron oxides in the +3 oxidation state have high magnetic ordering temperatures due to the size of the coupled moments. Here we prepare and characterize ScFeO3 (SFO), which under pressure and in strain-stabilized thin films adopts a polar variant of the corundum structure, one of the archetypal binary oxide structures. Polar corundum ScFeO3 has a weak ferromagnetic ground state below 356 K-this is in contrast to the purely antiferromagnetic ground state adopted by the well-studied ferroelectric BiFeO3.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000301161600027 Publication Date 2012-01-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-7863;1520-5126; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 13.858 Times cited 48 Open Access
Notes Approved Most recent IF: 13.858; 2012 IF: 10.677
Call Number UA @ lucian @ c:irua:97200 Serial 2658
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Author Verbeeck, J.; Tian, H.; Béché, A.
Title (down) A new way of producing electron vortex probes for STEM Type A1 Journal article
Year 2012 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 113 Issue Pages 83-87
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract A spiral holographic aperture is used in the condensor plane of a scanning transmission electron microscope to produce a focussed electron vortex probe carrying a topological charge of either −1, 0 or +1. The spiral aperture design has a major advantage over the previously used forked aperture in that the three beams with topological charge m=−1, 0, and 1 are not side by side in the specimen plane, but rather on top of each other, focussed at different heights. This allows us to have only one selected beam in focus on the sample while the others contribute only to a background signal. In this paper we describe the working principle as well as first experimental results demonstrating atomic resolution HAADF STEM images obtained with electron vortex probes. These results pave the way for atomic resolution magnetic information when combined with electron energy loss spectroscopy.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000300554400002 Publication Date 2011-10-31
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 62 Open Access
Notes J.V. wants to thank Miles Padgett for suggesting this setup and pointing to the relevant optics literature. Peter Schattschneider is acknowledged for in depth discussions on related topics. J.V acknowledges funding from the European Research Council under the 7th Framework Program (FP7), ERC Grant no. 46791-COUN-TATOMS and ERC Starting Grant no. 278510 VORTEX. The Qu-Ant-EM microscope is partially funded by the Hercules fund of the Flemish Government. ECASJO_; Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:93624UA @ admin @ c:irua:93624 Serial 2336
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Author Vandenberghe, W.G.; Verhulst, A.S.; Kao, K.-H.; De Meyer, K.; Sorée, B.; Magnus, W.; Groeseneken, G.
Title (down) A model determining optimal doping concentration and material's band gap of tunnel field-effect transistors Type A1 Journal article
Year 2012 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 100 Issue 19 Pages 193509-193509,4
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We develop a model for the tunnel field-effect transistor (TFET) based on the Wentzel-Kramer-Brillouin approximation which improves over existing semi-classical models employing generation rates. We hereby introduce the concept of a characteristic tunneling length in direct semiconductors. Based on the model, we show that a limited density of states results in an optimal doping concentration as well as an optimal material's band gap to obtain the highest TFET on-current at a given supply voltage. The observed optimal-doping trend is confirmed by 2-dimensional quantum-mechanical simulations for silicon and germanium. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4714544]
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000304108000098 Publication Date 2012-05-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.411 Times cited 25 Open Access
Notes ; William Vandenberghe gratefully acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). This work was supported by IMEC's Industrial Affiliation Program. ; Approved Most recent IF: 3.411; 2012 IF: 3.794
Call Number UA @ lucian @ c:irua:98948 Serial 2105
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Author Bernardi, A.; Becherini, F.; Bonazza, A.; Van Grieken, R.; et al.
Title (down) A methodology to monitor the pollution impact on historic buildings surfaces : the TeACH project Type P1 Proceeding
Year 2012 Publication Lecture notes in computer science T2 – Progress in Cultural Heritage Preservation : proceedings of EUROMED-2012, the 4th International Conference on Cultural Heritage / Ioannides, M. [edit.]; et al. Abbreviated Journal
Volume Issue Pages 765-775
Keywords P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract The available scenarios of pollutant trends in Europe indicate that the effect of industrial, domestic and transport emissions on corrosion and soiling will continue to constitute a serious threat to Cultural Heritage. Such effects require improved methods for a more accurate diagnosis, monitoring and assessment of the damage. Within this framework, the monitoring methodology applied within the European project TeACH (Technologies and tools to prioritize assessment and diagnosis of air pollution impact on immovable and movable cultural heritage) (2008-2012) allows to assess the impact of the main pollutants on historic buildings. As a part of this approach, a new kit able to monitor the environmental parameters critical for the conservation of architectural surfaces and to evaluate the related damage in terms of surface color change was developed. The monitoring methodology described in the present paper has valuable application potential in the definition of preventive conservation strategies for a wide range of heritage assets.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2012-10-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-3-642-34233-2 ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:126672 Serial 8222
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Author Verbeeck, J.; Béché, A.; van den Broek, W.
Title (down) A holographic method to measure the source size broadening in STEM Type A1 Journal article
Year 2012 Publication Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 120 Issue Pages 35-40
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Source size broadening is an important resolution limiting effect in modern STEM experiments. Here, we propose an alternative method to measure the source size broadening making use of a holographic biprism to create interference patterns in an empty Ronchigram. This allows us to measure the exact shape of the source size broadening with a much better sampling than previously possible. We find that the shape of the demagnified source deviates considerably from a Gaussian profile that is often assumed. We fit the profile with a linear combination of a Gaussian and a bivariate Cauchy distribution showing that even though the full width at half maximum is similar to previously reported measurements, the tails of the profile are considerable wider. This is of fundamental importance for quantitative comparison of STEM simulations with experiments as these tails make the image contrast dependent on the interatomic distance, an effect that cannot be reproduced by a single Gaussian profile of fixed width alone.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000308082600005 Publication Date 2012-06-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 29 Open Access
Notes This work was supported by funding from the European Research Council under the 7th Framework Program (FP7), ERC Grant no. 246791 COUNTATOMS and ERC Starting Grant 278510 VORTEX. The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. W. Van den Broek acknowledges funding from the Condor project, a project under the supervision of the Embedded Systems Institute (ESI) and FEI. This project is partially supported by the Dutch Ministry of Economic Affairs under the BSIK program. ECASJO_; Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:100466UA @ admin @ c:irua:100466 Serial 1483
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Author Vos, P.E.J.; Nikolova, I.; Janssen, S.
Title (down) A high-order model for accurately simulating the size distribution of ultrafine particles in a traffic tunnel Type A1 Journal article
Year 2012 Publication Atmospheric environment : an international journal Abbreviated Journal
Volume 59 Issue Pages 415-425
Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)
Abstract We present a computational model for simulating the dispersion of traffic emitted particulate matter inside a road tunnel, with an emphasis on the number concentration of ultrafine particles (UFP). The model primarily calculates the size distribution of the particle number concentration at each location inside the tunnel. The proposed model differs from existing models in the sense that it uses a continuous representation of the size distribution based upon the high-order finite element method and that it solves the governing equations using the state-of-the-art discontinuous Galerkin method. Next to the traditional transport processes, the model also implements the most important aerosol transformation processes such as coagulation, condensation and dry deposition. It is shown that based upon parametrisations found in literature, the process of condensation in a traffic tunnel cannot properly be modelled. Therefore, we present a correction factor that allows for a better parametrisation. The adequate performance of the model is demonstrated by both a verification study and a validation study. For the verification we show that the discretisation error converges consistently while for the validation we compare the modelled results with a suitable set of data from a UFP measurement campaign in a Taiwanese traffic tunnel. The model is shown to correctly simulate the observed behaviour and by applying a statistical model evaluation we demonstrate that the proposed model meets widely accepted air quality model acceptance criteria. (C) 2012 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000309081100047 Publication Date 2012-05-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1352-2310 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:101793 Serial 8033
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Author Vinchurkar, S.; De Backer, L.; Vos, W.; Van Holsbeke, C.; de Backer, J.; de Backer, W.
Title (down) A case series on lung deposition analysis of inhaled medication using functional imaging based computational fluid dynamics in asthmatic patients : effect of upper airway morphology and comparison with in vivo data Type A1 Journal article
Year 2012 Publication Inhalation Toxicology Abbreviated Journal Inhal Toxicol
Volume 24 Issue 2 Pages 81-88
Keywords A1 Journal article; Pharmacology. Therapy; Biophysics and Biomedical Physics; Condensed Matter Theory (CMT); Laboratory Experimental Medicine and Pediatrics (LEMP)
Abstract Context: Asthma affects 20 million Americans resulting in an economic burden of approximately $18 billion in the US alone (Allergies and Asthma Foundation 2000; National Center for Environmental Health (NCEH) 1999). Research studies based on differences in patient-specific airway morphology for asthma and the associated effect on deposition of inhaled aerosols are currently not available in the literature. Therefore, the role of morphological variations such as upper airway (extrathoracic) occlusion is not well documented. Objective: Functional imaging based computational fluid dynamics (CFD) of the respiratory airways for five asthmatic subjects is performed in this study using computed tomography (CT) based patient-specific airway models and boundary conditions. Methods: CT scans for 5 asthma patients were used to reconstruct 3D lung models using segmentation software. An averaged inhalation profile and patient-specific lobar flow distribution were used to perform the simulation. The simulations were used to obtain deposition for BDP/Formoterol (R) HFA pMDI in the patient-specific airway models. Results: The lung deposition obtained using CFD was in excellent agreement with available in vivo data using the same product. Specifically, CFD resulted in 30% lung deposition, whereas in vivo lung deposition was reported to be approximately 31%. Conclusion: It was concluded that a combination of patient-specific airway models and lobar boundary conditions can be used to obtain accurate lung deposition estimates. Lower lung deposition can be expected for patients with higher extrathoracic resistance. Novel respiratory drug delivery devices need to accommodate population subgroups based on these morphological and anatomical differences in addition to subject age.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000299744800001 Publication Date 2012-01-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0895-8378;1091-7691; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.751 Times cited 36 Open Access
Notes ; ; Approved Most recent IF: 1.751; 2012 IF: 1.894
Call Number UA @ lucian @ c:irua:96238 Serial 286
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Author Tan, H.; Turner, S.; Yucelen, E.; Verbeeck, J.; Van Tendeloo, G.
Title (down) 2D atomic mapping of oxidation states in transition metal oxides by scanning transmission electron microscopy and electron energy-loss spectroscopy : reply Type Editorial
Year 2012 Publication Physical review letters Abbreviated Journal Phys Rev Lett
Volume 108 Issue 25 Pages 259702
Keywords Editorial; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000305568700038 Publication Date 2012-06-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007 ISBN Additional Links UA library record; WoS full record
Impact Factor 8.462 Times cited Open Access
Notes Approved Most recent IF: 8.462; 2012 IF: 7.943
Call Number UA @ admin @ c:irua:100293 Serial 5370
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Author Tsirlin, A.A.; Abakumov, A.M.; Ritter, C.; Rosner, H.
Title (down) (CuCl)LaTa2O\text{7} and quantum phase transition in the (CuX)LaM2O7 family (X=Cl, Br; M=Nb, Ta) Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 86 Issue 6 Pages 064440-12
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We apply neutron diffraction, high-resolution synchrotron x-ray diffraction, magnetization measurements, electronic structure calculations, and quantum Monte-Carlo simulations to unravel the structure and magnetism of (CuCl)LaTa2O7. Despite the pseudo-tetragonal crystallographic unit cell, this compound features an orthorhombic superstructure, similar to the Nb-containing (CuX)LaNb2O7 with X = Cl and Br. The spin lattice entails dimers formed by the antiferromagnetic fourth-neighbor coupling J(4), as well as a large number of nonequivalent interdimer couplings quantified by an effective exchange parameter J(eff). In (CuCl)LaTa2O7, the interdimer couplings are sufficiently strong to induce the long-range magnetic order with the Neel temperature T-N similar or equal to 7 K and the ordered magnetic moment of 0.53 mu(B), as measured with neutron diffraction. This magnetic behavior can be accounted for by J(eff)/J(4) similar or equal to 1.6 and J(4) similar or equal to 16 K. We further propose a general magnetic phase diagram for the (CuCl)LaNb2O7-type compounds, and explain the transition from the gapped spin-singlet (dimer) ground state in (CuCl)LaNb2O7 to the long-range antiferromagnetic order in (CuCl)LaTa2O7 and (CuBr)LaNb2O7 by an increase in the magnitude of the interdimer couplings J(eff)/J(4), with the (CuCl)LaM2O7 (M = Nb, Ta) compounds lying on different sides of the quantum critical point that separates the singlet and long-range-ordered magnetic ground states.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000308127600006 Publication Date 2012-08-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 6 Open Access
Notes Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:101886 Serial 3526
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