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“Optimization of NBED simulations for disc-detection measurements”. Grieb T, Krause FF, Mahr C, Zillmann D, Müller-Caspary K, Schowalter M, Rosenauer A, Ultramicroscopy 181, 50 (2017). http://doi.org/10.1016/J.ULTRAMIC.2017.04.015
Abstract: Nano-beam electron diffraction (NBED) is a method which can be applied to measure lattice strain and polarisation fields in strained layer heterostructures and transistors. To investigate precision, accuracy and spatial resolution of such measurements in dependence of properties of the specimen as well as electron optical parameters, simulations of NBED patterns are required which allow to predict the result of common disc-detection algorithms. In this paper we demonstrate by focusing on the detection of the central disc in crystalline silicon that such simulations require to take several experimental characteristics into account in order to obtain results which are comparable to those from experimental NBED patterns. These experimental characteristics are the background intensity, the presence of Poisson noise caused by electron statistics and blurring caused by inelastic scattering and by the transfer quality of the microscope camera. By means of these optimized simulations, different effects of specimen properties on disc detection – such as strain, surface morphology and compositional changes on the nanometer scale – are investigated and discussed in the context of misinterpretation in experimental NBED evaluations. It is shown that changes in surface morphology and chemical composition lead to measured shifts of the central disc in the NBED pattern of tens to hundreds of grad. These shifts are of the same order of magnitude or even larger than shifts that could be caused by an electric polarisation field in the range of MV/cm. (C) 2017 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 6
DOI: 10.1016/J.ULTRAMIC.2017.04.015
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“The influence of acids on tuning the pore size of mesoporous TiO2 templated by non-ionic block copolymers”. Loreto S, Vanrompay H, Mertens M, Bals S, Meynen V, European journal of inorganic chemistry 2018, 62 (2018). http://doi.org/10.1002/EJIC.201701266
Abstract: <script type='text/javascript'>document.write(unpmarked('We show the possibility to tune the pore size of mesoporous TiO2 templated by non-ionic block copolymers by adding different inorganic acids at well-chosen concentration. The effect of the inorganic anions on both the TiO2 cluster formation and the non-ionic block copolymers micelles is investigated to explain the experimental results.'));
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 2.444
Times cited: 6
DOI: 10.1002/EJIC.201701266
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“Comparative study of the magnetic properties of La3Ni2B'O9 for B' = Nb, Ta or Sb”. Chin C-M, Battle PD, Blundell SJ, Hunter E, Lang F, Hendrickx M, Sena RP, Hadermann J, Journal of solid state chemistry 258, 825 (2018). http://doi.org/10.1016/J.JSSC.2017.12.018
Abstract: Polycrystalline samples of La3Ni2NbO9 and La3Ni2TaO9 have been characterised by X-ray and neutron diffraction, electron microscopy, magnetometry and muon spin relaxation (mu SR); the latter technique was also applied to La3Ni2SbO9. On the length scale of a neutron diffraction experiment, the six-coordinate sites of the monoclinic perovskite structure are occupied in a 1:1 ordered manner by Ni and a random 1/3Ni/2/3B' mixture. Electron microscopy demonstrated that this 1:1 ordering is maintained over microscopic distances, although diffuse scattering indicative of short-range ordering on the mixed site was observed. No magnetic Bragg scattering was observed in neutron diffraction patterns collected from La3Ni2B'O-9 (B' = Nb or Ta) at 5 K although in each case mu SR identified the presence of static spins below 30 K. Magnetometry showed that La3Ni2NbO9 behaves as a spin glass below 29 K but significant short-range interactions are present in La3Ni2NbO9 below 85 K. The contrasting properties of these compounds are discussed in terms of their microstructure.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 6
DOI: 10.1016/J.JSSC.2017.12.018
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“Diversified vortex phase diagram for a rotating trapped two-band Fermi gas in the BCS-BEC crossover”. Klimin SN, Tempere J, Milošević, MV, New journal of physics 20, 025010 (2018). http://doi.org/10.1088/1367-2630/AAACEB
Abstract: We report the equilibrium vortex phase diagram of a rotating two-band Fermi gas confined to a cylindrically symmetric parabolic trapping potential, using the recently developed finite-temperature effective field theory (Klimin et al 2016 Phys. Rev. A 94 023620). A non-monotonic resonant dependence of the free energy as a function of the temperature and the rotation frequency is revealed for a two-band superfluid. We particularly focus on novel features that appear as a result of interband interactions and can be experimentally resolved. The resonant dependence of the free energy is directly manifested in vortex phase diagrams, where areas of stability for both integer and fractional vortex states are found. The study embraces the BCS-BEC crossover regime and the entire temperature range below the critical temperature T-c. Significantly different behavior of vortex matter as a function of the interband coupling is revealed in the BCS and BEC regimes.
Keywords: A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 6
DOI: 10.1088/1367-2630/AAACEB
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“β-Na1.7IrO3: A Tridimensional Na-Ion Insertion Material with a Redox Active Oxygen Network”. Pearce PE, Rousse G, Karakulina OM, Hadermann J, Van Tendeloo G, Foix D, Fauth F, Abakumov AM, Tarascon J-M, Chemistry of materials 30, 3285 (2018). http://doi.org/10.1021/acs.chemmater.8b00320
Abstract: The revival of the Na-ion battery concept has prompted an intense search for new high capacity Na-based positive electrodes. Recently, emphasis has been placed on manipulating Na-based layered compounds to trigger the participation of the anionic network. We further explored this direction and show the feasibility of achieving anionic-redox activity in three-dimensional Na-based compounds. A new 3D β-Na1.7IrO3 phase was synthesized in a two-step process, which involves first the electrochemical removal of Li from β-Li2IrO3 to produce β-IrO3, which is subsequently reduced by electrochemical Na insertion. We show that β-Na1.7IrO3 can reversibly uptake nearly 1.3 Na+ per formula unit through an uneven voltage profile characterized by the presence of four plateaus related to structural transitions. Surprisingly, the β-Na1.7IrO3 phase was found to be stable up to 600 °C, while it could not be directly synthesized via conventional synthetic methods. Although these Na-based iridate phases are of limited practical interest, they help to understand how introducing highly polarizable guest ions (Na+) into host rocksalt-derived oxide structures affects the anionic redox mechanism.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 6
DOI: 10.1021/acs.chemmater.8b00320
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“Single Atom Detection from Low Contrast-to-Noise Ratio Electron Microscopy Images”. Fatermans J, den Dekker A J, Müller-Caspary K, Lobato I, O’Leary C M, Nellist P D, Van Aert S, Physical review letters 121, 056101 (2018). http://doi.org/10.1103/PhysRevLett.121.056101
Abstract: Single atom detection is of key importance to solving a wide range of scientific and technological problems. The strong interaction of electrons with matter makes transmission electron microscopy one of the most promising techniques. In particular, aberration correction using scanning transmission electron microscopy has made a significant step forward toward detecting single atoms. However, to overcome radiation damage, related to the use of high-energy electrons, the incoming electron dose should be kept low enough. This results in images exhibiting a low signal-to-noise ratio and extremely weak contrast, especially for light-element nanomaterials. To overcome this problem, a combination of physics-based model fitting and the use of a model-order selection method is proposed, enabling one to detect single atoms with high reliability.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Impact Factor: 8.462
Times cited: 6
DOI: 10.1103/PhysRevLett.121.056101
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“Nature of the Positron State in CdSe Quantum Dots”. Shi W, Callewaert V, Barbiellini B, Saniz R, Butterling M, Egger W, Dickmann M, Hugenschmidt C, Shakeri B, Meulenberg R W, Brück E, Partoens B, Bansil A, Eijt SW H, Physical review letters 121, 057401 (2018). http://doi.org/10.1103/PhysRevLett.121.057401
Abstract: Previous studies have shown that positron-annihilation spectroscopy is a highly sensitive probe of the electronic structure and surface composition of ligand-capped semiconductor quantum dots (QDs) embedded in thin films. The nature of the associated positron state, however, whether the positron is confined inside the QDs or localized at their surfaces, has so far remained unresolved. Our positron-annihilation lifetime spectroscopy studies of CdSe QDs reveal the presence of a strong lifetime component in the narrow range of 358–371 ps, indicating abundant trapping and annihilation of positrons at the surfaces of the QDs. Furthermore, our ab initio calculations of the positron wave function and lifetime employing a recent formulation of the weighted density approximation demonstrate the presence of a positron surface state and predict positron lifetimes close to experimental values. Our study thus resolves the long-standing question regarding the nature of the positron state in semiconductor QDs and opens the way to extract quantitative information on surface composition and ligand-surface interactions of colloidal semiconductor QDs through highly sensitive positron-annihilation techniques.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 6
DOI: 10.1103/PhysRevLett.121.057401
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“Understanding the Effect of Iodide Ions on the Morphology of Gold Nanorods”. Amini MN, Altantzis T, Lobato I, Grzelczak M, Sánchez-Iglesias A, Van Aert S, Liz-Marzán LM, Partoens B, Bals S, Neyts EC, Particle and particle systems characterization 35, 1800051 (2018). http://doi.org/10.1002/ppsc.201800051
Abstract: The presence of iodide ions during the growth of gold nanorods strongly affects the shape of the final products, which is proposed to be due to selective iodide adsorption on certain crystallographic facets. Therefore, a detailed structural and morphological characterization of the starting rods is crucial toward understanding this effect. Electron tomography is used to determine the crystallographic indices of the lateral facets of gold nanorods, as well as those present at the tips. Based on this information, density functional theory calculations are used to determine the surface and interface energies of the observed facets and provide insight into the relationship between the amount of iodide ions in the growth solution and the final morphology of anisotropic gold nanoparticles.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.474
Times cited: 6
DOI: 10.1002/ppsc.201800051
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“Electrostrictive behavior of confined water subjected to GPa pressure”. de Aquino BRH, Ghorbanfekr-Kalashami H, Neek-Amal M, Peeters FM, Physical review B 97, 144111 (2018). http://doi.org/10.1103/PHYSREVB.97.144111
Abstract: Water inside a nanocapillary exhibits unconventional structural and dynamical behavior due to its ordered structure. The confining walls, density, and lateral pressures control profoundly the microscopic structure of trapped water. Here we study the electrostriction of confined water subjected to pressures of the order of GPa for two different setups: (i) a graphene nanochannel containing a constant number of water molecules independent of the height of the channel, (ii) an open nanochannel where water molecules can be exchanged with those in a reservoir. For the former case, a square-rhombic structure of confined water is formed when the height of the channel is d = 6.5 angstrom having a density of rho = 1.42 g cm(-3). By increasing the height of the channel, a transition from a flat to a buckled state occurs, whereas the density rapidly decreases and reaches the bulk density for d congruent to 8.5 angstrom. When a perpendicular electric field is applied, the water structure and the lateral pressure change. For strong electric fields (similar to 1 V/angstrom), the square-rhombic structure is destroyed. For an open setup, a solid phase of confined water consisting of an imperfect square-rhombic structure is formed. By applying a perpendicular field, the density and phase of confined water change. However, the density and pressure inside the channel decrease as compared to the first setup. Our study is closely related to recent experiments on confined water, and it reveals the sensitivity of the microscopic structure of confined water to the size of the channel, the external electric field, and the experimental setup.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PHYSREVB.97.144111
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“Negative magnetoresistance in thin superconducting films with parallel orientation of current and magnetic field”. Vodolazov DY, Berdiyorov G, Peeters FM, Physica: C : superconductivity 552, 64 (2018). http://doi.org/10.1016/J.PHYSC.2018.07.002
Abstract: Thin superconducting films can exhibit negative magnetoresistance when an in-plane external magnetic field is aligned parallel with the transport current. We explain this effect as due to appearance of parallel vortices in the plain of the film at the first critical magnetic field H-c1 which leads to an enhancement of the superconducting properties and impedes the motion of the current induced perpendicular vortices. Our theoretical results are based on a numerical solution of the time-dependent and stationary 3D Ginzburg-Landau equations.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.404
Times cited: 6
DOI: 10.1016/J.PHYSC.2018.07.002
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“Ferrimagnetism as a consequence of unusual cation ordering in the Perovskite SrLa2FeCoSbO9”. Tang Y, Hunter EC, Battle PD, Hendrickx M, Hadermann J, Cadogan JM, Inorganic chemistry 57, 7438 (2018). http://doi.org/10.1021/ACS.INORGCHEM.8B01012
Abstract: A polycrystalline sample of SrLa2FeCoSbO9 has been prepared in a solid-state reaction and studied by a combination of electron microscopy, magnetometry, Mossbauer spectroscopy, X-ray diffraction, and neutron diffraction. The compound adopts a monoclinic (space group P2(1)/n; a = 5.6218(6), b = 5.6221(6), c = 7.9440(8) angstrom, beta = 90.050(7)degrees at 300 K) perovskite-like crystal structure with two crystallographically distinct six-coordinate sites. One of these sites is occupied by 2/3 Co-2(+),1/3 Fe3+ and the other by 2/3 Sb5+, 1/3 Fe3+. This pattern of cation ordering results in a transition to a ferrimagnetic phase at 215 K. The magnetic moments on nearest-neighbor, six-coordinate cations align in an antiparallel manner, and the presence of diamagnetic Sb5+ on only one of the two sites results in a nonzero remanent magnetization of similar to 1 mu(B) per formula unit at 5 K.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 6
DOI: 10.1021/ACS.INORGCHEM.8B01012
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“Confined states in graphene quantum blisters”. Abdullah HM, Bahlouli H, Peeters FM, Van Duppen B, Journal of physics : condensed matter 30, 385301 (2018). http://doi.org/10.1088/1361-648X/AAD9C7
Abstract: Bilayer graphene samples may exhibit regions where the two layers are locally delaminated forming a so-called quanttun blister in the graphene sheet. Electron and hole states can be confined in this graphene quantum blisters (GQB) by applying a global electrostatic bias. We scrutinize the electronic properties of these confined states under the variation of interlayer bias, coupling, and blister's size. The spectra display strong anti-crossings due to the coupling of the confined states on upper and lower layers inside the blister. These spectra are layer localized where the respective confined states reside on either layer or equally distributed. For finite angular momentum, this layer localization can be at the edge of the blister and corresponds to degenerate modes of opposite momenta. Furthermore, the energy levels in GQB exhibit electron-hole symmetry that is sensitive to the electrostatic bias. Finally, we demonstrate that confinement in GQB persists even in the presence of a variation in the interlayer coupling.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 6
DOI: 10.1088/1361-648X/AAD9C7
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“Correlation functions in electron-electron and electron-hole double quantum wells : temperature, density, and barrier-width dependence”. Dharma-Wardana MWC, Neilson D, Peeters FM, Physical review B 99, 035303 (2019). http://doi.org/10.1103/PHYSREVB.99.035303
Abstract: The classical-map hypernetted-chain (CHNC) scheme, developed for treating fermion fluids at strong coupling and at finite temperatures, is applied to electron-electron and electron-hole double quantum wells. The pair-distribution functions and the local field factors needed in linear-response theory are determined for a range of temperatures, carrier densities, and barrier widths typical for experimental double-quantum-well systems in GaAs-GaAlAs. For electron-hole double quantum wells, a large enhancement in the pair-distribution functions is found for small carrier separations. The CHNC equations for electron-hole systems no longer hold at low densities where bound-state formation occurs.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PHYSREVB.99.035303
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“Nanocrystal Core Size and Shape Substitutional Doping and Underlying Crystalline Order in Nanocrystal Superlattices”. Jishkariani D, Elbert KC, Wu Y, Lee JD, Hermes M, Wang D, van Blaaderen A, Murray CB, ACS nano 13, 5712 (2019). http://doi.org/10.1021/ACSNANO.9B01107
Abstract: Substitutional doping is a potentially powerful technique to control the properties of nanocrystal (NC) superlattices (SLs). However, not every NC can be substituted into any lattice, as the NCs have to be close in size and shape, limiting the application of substitutional doping. Here we show that this limitation can be overcome by employing ligands of various size. We show that small NCs with long ligands can be substituted into SLs of big NCs with short ligands. Furthermore, we show that shape differences can also be overcome and that cubes can substitute spheres when both are coated with long ligands. Finally, we use the NC effective ligand size, softness, and effective overall size ratio to explain observed doping behaviors.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.942
Times cited: 6
DOI: 10.1021/ACSNANO.9B01107
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“Tetragonal Cs1.17In0.81Cl3 : a charge-ordered indium halide perovskite derivative”. Tan X, Stephens PW, Hendrickx M, Hadermann J, Segre CU, Croft M, Kang C-J, Deng Z, Lapidus SH, Kim SW, Jin C, Kotliar G, Greenblatt M, Chemistry of materials 31, 1981 (2019). http://doi.org/10.1021/ACS.CHEMMATER.8B04771
Abstract: Polycrystalline samples of Cs1.17In0.81Cl3 were prepared by annealing a mixture of CsCl, InCl, and InCl3, stoichiometric for the targeted CsInCl3. Synchrotron powder X-ray diffraction refinement and chemical analysis by energy dispersive X-ray indicated that Cs1.17In0.81Cl3, a tetragonal distorted perovskite derivative (I4/m), is the thermodynamically stable product. The refined unit cell parameters and space group were confirmed by electron diffraction. In the tetragonal structure, In+ and In3+ are located in four different crystallographic sites, consistent with their corresponding bond lengths. In1, In2, and In3 are octahedrally coordinated, whereas In4 is at the center of a pentagonal bipyramid of Cl because of the noncooperative octahedral tilting of In4Cl6. The charged-ordered In+ and In3+ were also confirmed by X-ray absorption and Raman spectroscopy. Cs1.17In0.81Cl3 is the first example of an inorganic halide double perovskite derivative with charged-ordered In+ and In3+. Band structure and optical conductivity calculations were carried out with both generalized gradient approximation (GGA) and modified Becke-Johnson (mBJ) approach; the GGA calculations estimated the band gap and optical band gap to be 2.27 eV and 2.4 eV, respectively. The large and indirect band gap suggests that Cs1.17In0.81Cl3 is not a good candidate for photovoltaic application.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 6
DOI: 10.1021/ACS.CHEMMATER.8B04771
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“Accelerated Discovery of Efficient Solar Cell Materials Using Quantum and Machine-Learning Methods”. Choudhary K, Bercx M, Jiang J, Pachter R, Lamoen D, Tavazza F, Chemistry of materials 31, 5900 (2019). http://doi.org/10.1021/acs.chemmater.9b02166
Abstract: Solar energy plays an important role in solving serious environmental
problems and meeting the high energy demand. However, the lack of suitable
materials hinders further progress of this technology. Here, we present the largest
inorganic solar cell material search till date using density functional theory (DFT) and
machine-learning approaches. We calculated the spectroscopic limited maximum
efficiency (SLME) using the Tran−Blaha-modified Becke−Johnson potential for 5097
nonmetallic materials and identified 1997 candidates with an SLME higher than 10%,
including 934 candidates with a suitable convex-hull stability and an effective carrier
mass. Screening for two-dimensional-layered cases, we found 58 potential materials
and performed G0W0 calculations on a subset to estimate the prediction uncertainty. As the above DFT methods are still computationally expensive, we developed a high accuracy machine-learning model to prescreen efficient materials and applied it to over a million materials. Our results provide a general framework and universal strategy for the design of high-efficiency solar
cell materials. The data and tools are publicly distributed at: https://www.ctcms.nist.gov/~knc6/JVASP.html, https://www.
ctcms.nist.gov/jarvisml/, https://jarvis.nist.gov/, and https://github.com/usnistgov/jarvis.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 6
DOI: 10.1021/acs.chemmater.9b02166
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“Chemical and Structural Configuration of Pt Doped Metal Oxide Thin Films Prepared by Atomic Layer Deposition”. Ramachandran RK, Filez M, Solano E, Poelman H, Minjauw MM, Van Daele M, Feng J-Y, La Porta A, Altantzis T, Fonda E, Coati A, Garreau Y, Bals S, Marin GB, Detavernier C, Dendooven J, Chemistry of materials 31, 9673 (2019). http://doi.org/10.1021/acs.chemmater.9b03066
Abstract: Pt doped semiconducting metal oxides and Pt metal clusters embedded in an oxide matrix are of interest for applications such as catalysis and gas sensing, energy storage and memory devices. Accurate tuning of the dopant level is crucial for adjusting the properties of these materials. Here, a novel atomic layer deposition (ALD) based method for doping Pt into In2O3 in specific, and metals in metal oxides in general, is demonstrated. This approach combines alternating exposures of Pt and In2O3 ALD processes in a single ‘supercycle’, followed by supercycle repetition leading to multilayered nanocomposites. The atomic level control of ALD and its conformal nature make the method suitable for accurate dopant control even on high surface area supports. Oxidation state, local structural environment and crystalline phase of the embedded Pt dopants were obtained by means of X-ray characterization methods and high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). In addition, this approach allows characterization of the nucleation stages of metal ALD processes, by stacking those states multiple times in an oxide matrix. Regardless of experimental conditions, a few Pt ALD cycles leads to the formation of oxidized Pt species due to their highly dispersed nature, as proven by X-ray absorption spectroscopy (XAS). Grazing-incidence small-angle X-ray scattering (GISAXS) and highresolution scanning transmission electron microscopy, combined with energy dispersive X-ray spectroscopy (HR-STEM/EDXS) show that Pt is evenly distributed in the In2O3 metal oxide matrix without the formation of clusters. For a larger number of Pt ALD
cycles, typ. > 10, the oxidation state gradually evolves towards fully metallic, and metallic Pt clusters are obtained within the In2O3 metal oxide matrix. This work reveals how tuning of the ALD supercycle approach for Pt doping allows controlled engineering of the Pt compositional and structural configuration within a metal oxide matrix.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 9.466
Times cited: 6
DOI: 10.1021/acs.chemmater.9b03066
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“Cold Atmospheric Plasma-Treated PBS Eliminates Immunosuppressive Pancreatic Stellate Cells and Induces Immunogenic Cell Death of Pancreatic Cancer Cells”. Van Loenhout J, Flieswasser T, Freire Boullosa L, De Waele J, Van Audenaerde J, Marcq E, Jacobs J, Lin A, Lion E, Dewitte H, Peeters M, Dewilde S, Lardon F, Bogaerts A, Deben C, Smits E, Cancers 11, 1597 (2019). http://doi.org/10.3390/cancers11101597
Abstract: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers with a low response to treatment and a five-year survival rate below 5%. The ineffectiveness of treatment is partly because of an immunosuppressive tumor microenvironment, which comprises tumor-supportive pancreatic stellate cells (PSCs). Therefore, new therapeutic strategies are needed to tackle both the immunosuppressive PSC and pancreatic cancer cells (PCCs). Recently, physical cold atmospheric plasma consisting of reactive oxygen and nitrogen species has emerged as a novel treatment option for cancer. In this study, we investigated the cytotoxicity of plasma-treated phosphate-buffered saline (pPBS) using three PSC lines and four PCC lines and examined the immunogenicity of the induced cell death. We observed a decrease in the viability of PSC and PCC after pPBS treatment, with a higher efficacy in the latter. Two PCC lines expressed and released damage-associated molecular patterns characteristic of the induction of immunogenic cell death (ICD). In addition, pPBS-treated PCC were highly phagocytosed by dendritic cells (DCs), resulting in the maturation of DC. This indicates the high potential of pPBS to trigger ICD. In contrast, pPBS induced no ICD in PSC. In general, pPBS treatment of PCCs and PSCs created a more immunostimulatory secretion profile (higher TNF-α and IFN-γ, lower TGF-β) in coculture with DC. Altogether, these data show that plasma treatment via pPBS has the potential to induce ICD in PCCs and to reduce the immunosuppressive tumor microenvironment created by PSCs. Therefore, these data provide a strong experimental basis for further in vivo validation, which might potentially open the way for more successful combination strategies with immunotherapy for PDAC.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Laboratory for Experimental Hematology (LEH); Center for Oncological Research (CORE)
Times cited: 6
DOI: 10.3390/cancers11101597
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“A Roman Egyptian Painting Workshop : technical investigation of the portraits from Tebtunis, Egypt”. Salvant J, Williams J, Ganio M, Casadio F, Daher C, Sutherland K, Monico L, Vanmeert F, De Meyer S, Janssens K, Cartwright C, Walton M, Archaeometry 60, 815 (2018). http://doi.org/10.1111/ARCM.12351
Abstract: Roman-period mummy portraits are considered to be ancient antecedents of modern portraiture. However, the techniques and materials used in their manufacture are not thoroughly understood. Analytical study of the pigments as well as the binding materials helps to address questions on what aspects of the painting practices originate from Pharaonic and/or Graeco-Roman traditions, and can aid in determining the provenance of the raw materials from potential locations across the ancient Mediterranean and European worlds. Here, one of the largest assemblages of mummy portraits to remain intact since their excavation from the site of Tebtunis in Egypt was examined using multiple analytical techniques to address how they were made. The archaeological evidence suggests that these portraits were products of a single workshop and, correspondingly, they are found to be made using similar techniques and materials: wax-based and lead white-rich paint combined with a variety of iron-based pigments (including hematite, goethite and jarosite), as well as Egyptian blue, minium, indigo and madder lake to create subtle variations and tones.
Keywords: A1 Journal article; History; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.47
Times cited: 6
DOI: 10.1111/ARCM.12351
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“Alteration of fossil-bearing shale (Autun, France, Permian), part II : monitoring artificial and natural ageing by combined use of S and Ca K-edge XANES analysis, Rock-Eval pyrolysis and FTIR analysis”. Odin GP, Vanmeert F, Farges F, Gand G, Janssens K, Romero-Sarmiento M-F, Steyer JS, Vantelon D, Rouchon V, Annales de paléontologie 101, 225 (2015). http://doi.org/10.1016/J.ANNPAL.2015.03.001
Abstract: Fossil-bearing shale specimens that include sulfides in their compositions are chemically reactive and sometimes also mechanically fragile. This decay is often related to iron sulfate efflorescence resulting from the oxidation of sulfide compounds. The processes underlying these degradations are poorly known, thus impeding the elaboration of curative or preventive treatments. The present contribution aims to identify the origin of museum specimen alterations. It focuses on the Flouest collection housed at the Museum National d'Histoire Naturelle (MNHN, Paris, France) and originating from the Autun Basin (Saone-et-Loire, France, Permian). To evaluate the alteration of MNHN specimens, it appeared necessary to compare their composition with that of unaltered shale so as to identify chemical changes occurring during ageing. Therefore, new material was collected in the Autun Basin, among others on the locality of Muse that corresponds to the same lithostratigraphic unit as that of the MNHN specimens. This material was, if necessary, artificially aged. The first part of this work, presented elsewhere, deals with the use of Xray diffraction and Mossbauer spectroscopy for characterizing iron reactivity and speciation. It leads to the conclusion that the reactivity of iron in the shale matrix was limited and could not account for the large efflorescence of iron (II) sulfate occurring nearby the fossil. The second part presented here focuses on the use of S K-edge X-ray Absorption Near Edge Structure (XANES) spectroscopy for characterizing sulfur speciation and reactivity. Measurements were performed on the shale matrix and on thin layers of maceral found in the proximity of damaged areas. As sulfur may be found in association with calcium or organic matter, complementary techniques were implemented, such as FTIR spectroscopy, Rock-Eval pyrolysis (characterization of organic matter content) and Ca K-edge XANES (analysis of calcium speciation) spectroscopy. It was shown that sulfur is mainly related to thioether, sulfoxide, iron sulfide, and sulfates whereas calcium is mainly bound to carboxylate, carbonate and/or sulfate groups. FTIR analysis of the macerals confirmed the presence of vitrinite on damaged MNHN specimens. The low oxygen content of new shale samples determined by Rock-Eval pyrolysis indicates that the organic matter is well preserved, despite the fact that samples come from outcrop surface. In the newly collected material, sulfur is mainly related to organic sulfides (thioether) with a minor occurrence of iron sulfide. In the shale fraction of damaged MNHN specimens, sulfur is mostly oxidized into a mixture of iron and calcium sulfate. However, in the vitrinite layers of the same specimens, a large proportion of sulfur corresponds to organic sulfides. Also the oxidation of sulfur does not occur homogeneously but preferentially in the shale fraction, probably because this latter is porous whereas vitrinite is not. Artificial ageing of new shale material showed that the oxidation of organic sulfides could be reproduced at 90 degrees C, 80% of relative humidity. However, the obtained efflorescence almost exclusively corresponds to calcium sulfate whereas iron (II) sulfates are mostly observed on MNHN specimens. The new material collected on site is probably to be questioned, and future studies will have to select new samples with fossil remains. This will be the object of the third part of this work. (C) 2015 Elsevier Masson SAS. All rights reserved.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.113
Times cited: 6
DOI: 10.1016/J.ANNPAL.2015.03.001
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“Cephalosporin antibiotics : electrochemical fingerprints and core structure reactions investigated by LC-MSMS”. Sleegers N, van Nuijs ALN, van den Berg M, De Wael K, Analytical chemistry 91, 2035 (2019). http://doi.org/10.1021/ACS.ANALCHEM.8B04487
Abstract: Electrochemistry and exploiting electrochemical fingerprints is a potent approach to address newly emerging surveillance needs, for instance for antibiotics. However, a comprehensive insight in the electrochemical oxidation behaviour and mechanism is re-quired for this sensing strategy. To address the lack in knowledge of the voltammetric behaviour of the cephalosporins antibiotics, a selection of cephalosporin antibiotics and two main intermediates were subjected to an electrochemical study of their redox behaviour by means of pulsed voltammetric techniques and small-scale electrolysis combined with HPLC-MS/MS analyses. Sur-prisingly, the detected oxidation products did not fit the earlier suggested oxidation of the sulfur group to the corresponding sul-foxide. The influence of different side chains, both at the three and the seven position of the β-lactam core structure on the elec-trochemical fingerprint were investigated. Additional oxidation signals at lower potentials were elucidated and linked to different side chains. These signals were further exploited to allow simultaneous detection of different cephalosporins in one voltammetric sweep. These fundamental insights can become the building blocks for an new on-site screening method.
Keywords: A1 Journal article; Pharmacology. Therapy; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre
Impact Factor: 6.32
Times cited: 6
DOI: 10.1021/ACS.ANALCHEM.8B04487
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“An N-myristoylated globin with a redox-sensing function that regulates the defecation cycle in Caenorhabditis elegans”. Tilleman L, De Henau S, Pauwels M, Nagy N, Pintelon I, Braeckman BP, De Wael K, Van Doorslaer S, Adriaensen D, Timmermans J-P, Moens L, Dewilde S, PLoS ONE 7, e48768 (2012). http://doi.org/10.1371/JOURNAL.PONE.0048768
Abstract: Globins occur in all kingdoms of life where they fulfill a wide variety of functions. In the past they used to be primarily characterized as oxygen transport/storage proteins, but since the discovery of new members of the globin family like neuroglobin and cytoglobin, more diverse and complex functions have been assigned to this heterogeneous family. Here we propose a function for a membrane-bound globin of C. elegans, GLB-26. This globin was predicted to be myristoylated at its N-terminus, a post-translational modification only recently described in the globin family. In vivo, this globin is found in the membrane of the head mesodermal cell and in the tail stomato-intestinal and anal depressor muscle cells. Since GLB-26 is almost directly oxidized when exposed to oxygen, we postulate a possible function as electron transfer protein. Phenotypical studies show that GLB-26 takes part in regulating the length of the defecation cycle in C. elegans under oxidative stress conditions.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 2.806
Times cited: 6
DOI: 10.1371/JOURNAL.PONE.0048768
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“Urban air pollutants and their micro effects on medieval stained glass windows”. Kontozova-Deutsch V, Deutsch F, Godoi RHM, Van Grieken R, De Wael K, Microchemical journal 99, 508 (2011). http://doi.org/10.1016/J.MICROC.2011.07.003
Abstract: Levels of urban gaseous and particulate pollutants were investigated in the Cathedral of Cologne, Germany in the framework of the EU-project VIDRIO. The purpose of this study was to evaluate the influence of a protective double glazing system on the preservation of ancient stained glass windows by sampling at protected and unprotected windows (indoors, in the interspace and outdoor of the Cathedral). The interspace between the ancient stained glass window and the protective glazing is flushed in the Cathedral by indoor air, hence isolating the historic glass from the outdoor air and exposing it to indoor air on both sides of the glass panels. Concentrations of aggressive gaseous pollutants such as NO2, SO2, O3 and CO2 as well as elemental concentrations of bulk particles and relative abundances of single particles were surveyed at all sampling locations. Elemental concentrations in bulk particulate matter were found to be significantly lower inside the Cathedral in comparison to the outdoor air. This result is advantageous for the stained glass windows. Single particle analysis of the samples from Cologne showed also soil dust and organic particles as well as sulphates and nitrates, from which the latter two compounds are dangerous for the stained glass windows. On the base of the obtained results, it can be concluded that the protective glazing system in the Cathedral of Cologne can be considered as predominantly advantageous from both the gases' point of view (except for NO2-candles burning) and from the particles' point of view.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.034
Times cited: 6
DOI: 10.1016/J.MICROC.2011.07.003
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“Harvesting hydrogen gas from air pollutants with an un-biased gas phase photo-electrochemical cell”. Verbruggen SW, Van Hal M, Bosserez T, Rongé, J, Hauchecorne B, Martens JA, Lenaerts S, Chemsuschem 10, 1413 (2017). http://doi.org/10.1002/CSSC.201601806
Abstract: The concept of an all-gas-phase photo-electrochemical cell (PEC) producing hydrogen gas from volatile organic contaminated gas and light is presented. Without applying any external bias, organic contaminants are degraded and hydrogen gas is produced in separate electrode compartments. The system works most efficiently with organic pollutants in inert carrier gas. In the presence of oxygen gas, the cell performs less efficiently but still significant photocurrents are generated, showing the cell can be run on organic contaminated air. The purpose of this study is to demonstrate new application opportunities of PEC technology and to encourage further advancement toward photo-electrochemical remediation of air pollution with the attractive feature of simultaneous energy recovery and pollution abatement.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 7.226
Times cited: 6
DOI: 10.1002/CSSC.201601806
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“Hierarchically dual-mesoporous TiO2 microspheres for enhanced photocatalytic properties and lithium storage”. Xiao S, Lu Y, Xiao B-Y, Wu L, Song J-P, Xiao Y-X, Wu S-M, Hu J, Wang Y, Chang G-G, Tian G, Lenaerts S, Janiak C, Yang X-Y, Su B-L, Chemistry: a European journal 24, 13246 (2018). http://doi.org/10.1002/CHEM.201801933
Abstract: Hierarchically dual‐mesoporous TiO2 microspheres have been synthesized via a solvothermal process in the presence of 1‐butyl‐3‐methylmidazolium tetrafluoroborate ([BMIm][BF4]) and diethylenetriamine (DETA) as co‐templates. Secondary mesostructured defects in the hierarchical TiO2 microspheres produce the oxygen vacancies, which not only significantly enhance the photocatalytic activity on degrading methyl blue (over 1.7 times to P25) and acetone (over 2.9 times of P25), but which also are beneficial for lithium storage. Moreover, we propose a mechanism to obtain a better understanding of the role of dual mesoporosity of TiO2 microspheres for enhancing the molecular diffusion, ion transportation and electron transformation.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 5.317
Times cited: 6
DOI: 10.1002/CHEM.201801933
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“Integrated assessment of agro-ecological systems : the case study of the “Alta Murgia&rdquo, National park in Italy”. Moretti M, De Boni A, Roma R, Fracchiolla M, Van Passel S, Agricultural Systems 144, 144 (2016). http://doi.org/10.1016/J.AGSY.2016.02.007
Abstract: Several indicators and methods are already applied for sustainability assessment in agriculture. The links between sustainability indicators, agricultural management and policies are not well explained. The aim of this study is to combine biophysical and monetary sustainability assessment tools to support agriculture policy decision-making. Three methodological steps are considered: i) the environmental impacts of farms are assessed using terrestrial acidification, freshwater eutrophication, soil and freshwater ecotoxicity as well as natural land transformation; ii) the most relevant indicators of agriculture damages on ecosystems quality are aggregated into an index; iii) the farms' index scores are integrated with farm assets, land and labor, into the Sustainable Value approach (SVA), as indicator of natural resources used by farms. As a case study, the methodology was applied to arable farms with and without animal husbandry of the “Alta Murgia” National Park. The crop farms, in our sample, have a higher sustainable value using their economic and environmental resources. Mixed farms need to improve their resources use efficiency. Although crop farms have lower land-use efficiency compared to mixed farms, our results suggest supporting, by means of policy options, the specialized crop farms that, on average, perform better in terms of ecosystems quality preservation. Finally, we find that Life Cycle Assessment (LCA) to soundly measure the environmental impacts clearly enriches the SVA. (C) 2016 Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering Management (ENM)
Impact Factor: 2.571
Times cited: 6
DOI: 10.1016/J.AGSY.2016.02.007
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“Agricultural land conversion drivers in Northeast Iran : application of structural equation model”. Azadi H, Akbar Barati A, Rafiaani P, Raufirad V, Zarafshani K, Mamoorian M, Van Passel S, Lebailly P, Applied Spatial Analysis And Policy 9, 591 (2016). http://doi.org/10.1007/S12061-015-9160-4
Abstract: Identifying driving forces behind agricultural land conversion (ALC) remains one of the most difficult challenges that agricultural and environmental scientists must continually deal with. The difficulty emerges from the fact that in ALC, multiple actions and interactions between different factors (i.e., economic, political, environmental, biophysical, institutional, and cultural) exist and make it difficult to understand the function of the processes behind the changes. The phenomenon of ALC in different countries is varied in terms of intensity, trends and drivers. The main goal of this study was to understand these drivers in Northeast Iran through applying structural equation model (SEM). Using multi-stage stratified random sampling, 101 executive officers participated in the study. Data were collected through a structured questionnaire. A multi-stakeholder analysis and a mixed-method (qualitative and quantitative) approach were applied. Results revealed that not only from the policy makers perspective but also based on the SEM, economic, political, technological, social and environmental factors should respectively be the five major drivers of ALC. The results also showed that among other drivers, more profitability of non-agriculture sectors, excessive rising of land prices, farmers income instability, land fragmentation, urban sprawl and inheritance laws are the main six causes of ALC. Hence, it can be concluded that policy-makers and planners need to take these drivers and subsidiaries more into consideration in order to properly respond to ALC.
Keywords: A1 Journal article; Economics; Engineering Management (ENM)
Impact Factor: 1.825
Times cited: 6
DOI: 10.1007/S12061-015-9160-4
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“Non-thermal plasma-induced immunogenic cell death in cancer”. Khalili M, Daniels L, Lin A, Krebs FC, Snook AE, Bekeschus S, Bownel WB, Miller V, Journal of physics: D: applied physics 52, 423001 (2019). http://doi.org/10.1088/1361-6463/AB31C1
Abstract: Recent advances in biomedical research in cancer immunotherapy have identified the use of an oxidative stress-based approach to treat cancers, which works by inducing immunogenic cell death (ICD) in cancer cells. Since the anti-cancer effects of non-thermal plasma (NTP) are largely attributed to the reactive oxygen and nitrogen species that are delivered to and generated inside the target cancer cells, it is reasonable to postulate that NTP would be an effective modality for ICD induction. NTP treatment of tumors has been shown to destroy cancer cells rapidly and, under specific treatment regimens, this leads to systemic tumorspecific immunity. The translational benefit of NTP for treatment of cancer relies on its ability to enhance the interactions between NTP-exposed minor cells and local immune cells which initiates subsequent protective immune responses. This review discusses results from recent investigations of NTP application to induce ICD in cancer cells. With further optimization of clinical devices and treatment protocols, NTP can become an essential part of the therapeutic armament against cancer.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
Times cited: 6
DOI: 10.1088/1361-6463/AB31C1
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“On the importance of the work function and electron carrier density of oxide electrodes for the functional properties of ferroelectric capacitors”. Wang J, Nguyen MD, Gauquelin N, Verbeeck J, Do MT, Koster G, Rijnders G, Houwman E, Physica Status Solidi-Rapid Research Letters 14, 1900520 (2020). http://doi.org/10.1002/PSSR.201900520
Abstract: It is important to understand the effect of the interfaces between the oxide electrode layers and the ferroelectric layer on the polarization response for optimizing the device performance of all-oxide ferroelectric devices. Herein, the effects of the oxide La0.07Ba0.93SnO3 (LBSO) as an electrode material in an PbZr0.52Ti0.48O3 (PZT) ferroelectric capacitor are compared with those of the more commonly used SrRuO3 (SRO) electrode. SRO (top)/PZT/SRO (bottom), SRO/PZT/LBSO, and SRO/PZT/2 nm SRO/LBSO devices are fabricated. Only marginal differences in crystalline properties, determined by X-ray diffraction and scanning transmission electron microscopy, are found. High-quality polarization loops are obtained, but with a much larger coercive field for the SRO/PZT/LBSO device. In contrast to the SRO/PZT/SRO device, the polarization decreases strongly with increasing field cycling. This fatigue problem can be remedied by inserting a 2 nm SRO layer between PZT and LBSO. It is argued that strongly increased charge injection into the PZT occurs at the bottom interface, because of the low PZT/LBSO interfacial barrier and the much lower carrier density in LBSO, as compared with that in SRO, causing a low dielectric constant, depleted layer in LBSO. The charge injection creates a trapped space charge in the PZT, causing the difference in fatigue behavior.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.8
Times cited: 6
DOI: 10.1002/PSSR.201900520
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“Open circuit voltage generated by dragging superconducting vortices with a dynamic pinning potential”. Xue C, He A, Milošević, MV, Silhanek A V, Zhou Y-H, New journal of physics 21, 113044 (2019). http://doi.org/10.1088/1367-2630/AB54AE
Abstract: We theoretically investigate, through Ginzburg?Landau simulations, the possibility to induce an open circuit voltage in absence of applied current, by dragging superconducting vortices with a dynamic pinning array as for instance that created by a nearby sliding vortex lattice or moving laser spots. Different dynamic regimes, such as synchronous vortex motion or dynamic vortex chains consisting of laggard vortices, can be observed by varying the velocity of the sliding pinning potential and the applied magnetic field. Additionally, due to the edge barrier, significantly different induced voltage is found depending on whether the vortices are dragged along the superconducting strip or perpendicular to the lateral edges. The output voltage in the proposed mesoscopic superconducting dynamo can be tuned by varying size, density and directions of the sliding pinning potential.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.786
Times cited: 6
DOI: 10.1088/1367-2630/AB54AE
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