“Hf/porphyrin-based metal-organic framework PCN-224 for CO2 cycloaddition with epoxides”. Carrasco S, Orcajo G, Martínez F, Imaz I, Kavak S, Arenas-Esteban D, Maspoch D, Bals S, Calleja G, Horcajada P, Materials Today Advances 19, 100390 (2023). http://doi.org/10.1016/j.mtadv.2023.100390
Abstract: Herein, we describe for the first time the synthesis of the highly porous Hf-tetracarboxylate porphyrin-based metal-organic framework (MOF) (Hf)PCN-224(M) (M = H2, Co2+). (Hf)PCN-224(H2) was easily and efficiently prepared following a simple microwave-assisted procedure with good yields (56–67%; space-time yields: 1100–1270 kg m−3·day−1), high crystallinity and phase purity by using trifluoromethanesulfonic acid and benzoic acid as modulators in less than 30 min. By simply introducing a preliminary step (10 min), 5,10,15,20-(tetra-4-carboxyphenyl)porphyrin linker (TCPP) was quantitatively metalated with Co2+ without additional purification and/or time consuming protection/deprotection steps to further obtain (Hf)PCN-224(Co). (Hf)PCN-224(Co) was then tested as catalyst in CO2 cycloaddition reaction with different epoxides to yield cyclic carbonates, showing the best catalytic performance described to date compared to other PCNs, under mild conditions (1 bar CO2, room temperature, 18–24 h). Twelve epoxides were tested, obtaining from moderate to excellent conversions (35–96%). Moreover, this reaction was gram scaled-up (x50) without significant loss of yield to cyclic carbonates. (Hf)PCN-224(Co) maintained its integrity and crystallinity even after 8 consecutive runs, and poisoning was efficiently reverted by a simple thermal treatment (175 °C, 6 h), fully recovering the initial catalytic activity.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 10
Times cited: 1
DOI: 10.1016/j.mtadv.2023.100390
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“Cavity nucleation and growth in Cu-Zn-Al irradiated with Cu+ ions at different temperatures”. Zelaya E, Schryvers D, Tolley A, Fitchner PFP, Intermetallics 18, 493 (2010). http://doi.org/10.1016/j.intermet.2009.09.010
Abstract: The effects of high dose ion irradiation in β CuZnAl were investigated between room temperature and 150 °C. Single crystal samples with surface normal close to [001]β were irradiated with 300 keV Cu+ ions. Microstructural changes were characterized using transmission electron microscopy. Irradiation induced cavities located on the surface exposed to the irradiation were observed. The morphology, size and density distribution of these cavities were analyzed as a function of different irradiation conditions. The shape and location of the cavities with respect to the irradiation surface were not affected by irradiation temperature or irradiation dose. Instead, the cavity size distribution showed a bi-modal shape for a dose of 15 dpa, regardless of irradiation temperature. For a dose of 30 dpa the bi-modal distribution was only observed after room temperature irradiation. The diffusion effects of vacancies produced by irradiation are analyzed in shape memory CuZnAl alloys, which main characteristic is the diffusionless martensitic transformation. Particularly, the cavity size distributions were analyzed in terms of nucleation, growth and coalescence.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.14
Times cited: 1
DOI: 10.1016/j.intermet.2009.09.010
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“Effect of mold hardness on microstructure and contraction porosity in ductile cast iron”. Khalil-Allafi J, Amin-Ahmadi B, Journal of iron and steel research international 18, 44 (2011). http://doi.org/10.1016/S1006-706X(11)60048-4
Abstract: The effect of mold hardness on the microstructure of ductile iron and the contraction porosity was investigated. Molds with different hardnesses (0.41, 0.48, 0.55, 0.62 MPa) and a sand mold prepared by Co2 method were used. The influence of silicon content on the induced expansion pressure owing to the formation of graphite was also investigated. The contraction during solidification can be compensated by an induced expansion owing to the graphite relief when the hardness of mold increases; therefore, the possibility of achieving a sound product without using any riser increases.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.836
Times cited: 1
DOI: 10.1016/S1006-706X(11)60048-4
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“The mode-deviation effect of trapped spinor bose gas beyond mean field theory”. Xu Y, Jia D-J, Chen Z, Gao Y, Li F-S, International journal of modern physics: B: condensed matter physics, statistical physics, applied physics 18, 1339 (2004). http://doi.org/10.1142/S0217979204024719
Abstract: The deviation effect of spinor mode from the single-mode for a spin-1 Bose gas of trapped atoms is studied beyond the mean field theory. Based on the effective Hamiltonian with nondegenerated level of the collective spin states, the splitting level of the system energy due to the deviation effect has been calculated. For the large condensates of (87)Rb and (23)Na with atom number N > 10(5), the splitting fraction of the energy, arising from the magnetization exhibited by the trapped Bose gas, is found to have a typical order of (10(-4) similar to 10(-8)), decreasing as N(-2) for (87)Rb and increasing as -N(-2) for 23 Na, respectively.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 0.736
Times cited: 1
DOI: 10.1142/S0217979204024719
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“On the phase-like nature of the 7M structure in Ni-Al”. Schryvers D, Tanner LE, MRS Japan: shape memory materials 18, 849 (1993)
Keywords: A3 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 1
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“Vortex states in mescopic superconductors”. Peeters FM, Baelus BJ, Milošević, MV, Physica. E: Low-dimensional systems and nanostructures 18, 312 (2003). http://doi.org/10.1016/S1386-9477(02)01058-5
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.221
Times cited: 1
DOI: 10.1016/S1386-9477(02)01058-5
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“Social risk screening using a socio-political ambiguity approach : the case of organic agriculture in Iran”. Mahmoudi H, Renn O, Hoffmann V, Van Passel S, Azadi H, Journal Of Risk Research 18, 747 (2015). http://doi.org/10.1080/13669877.2014.910696
Keywords: A1 Journal article; Sociology; Engineering Management (ENM)
Impact Factor: 1.34
Times cited: 1
DOI: 10.1080/13669877.2014.910696
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“HREM of ceramic high Tc superconductors”. Van Tendeloo G, Krekels T, Journal of the European Ceramic Society 16, 367 (1996). http://doi.org/10.1016/0955-2219(95)00193-X
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.947
Times cited: 1
DOI: 10.1016/0955-2219(95)00193-X
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“Color-switchable nanosilicon fluorescent probes”. Chen H, Xu J, Wang Y, Wang D, Ferrer-Espada R, Wang Y, Zhou J, Pedrazo-Tardajos A, Yang M, Tan J-H, Yang X, Zhang L, Sychugov I, Chen S, Bals S, Paulsson J, Yang Z, ACS nano 16, 15450 (2022). http://doi.org/10.1021/ACSNANO.2C07443
Abstract: Fluorescent probes are vital to cell imaging by allowing specific parts of cells to be visualized and quantified. Color-switchable probes (CSPs), with tunable emission wavelength upon contact with specific targets, are particularly powerful because they not only eliminate the need to wash away all unbound probe but also allow for internal controls of probe concentrations, thereby facilitating quantification. Several such CSPs exist and have proven very useful, but not for all key cellular targets. Here we report a pioneering CSP for in situ cell imaging using aldehydefunctionalized silicon nanocrystals (SiNCs) that switch their intrinsic photoluminescence from red to blue quickly when interacting with amino acids in live cells. Though conventional probes often work better in cell-free extracts than in live cells, the SiNCs display the opposite behavior and function well and fast in universal cell lines at 37 ? while requiring much higher temperature in extracts. Furthermore, the SiNCs only disperse in cytoplasm not nucleus, and their fluorescence intensity correlated linearly with the concentration of fed amino acids. We believe these nanosilicon probes will be promising tools to visualize distribution of amino acids and potentially quantify amino acid related processes in live cells.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 17.1
Times cited: 1
DOI: 10.1021/ACSNANO.2C07443
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“Atomic resolution mapping using quantitative high-angle annular dark field scanning transmission electron microscopy”. Van Aert S, Verbeeck J, Bals S, Erni R, van Dyck D, Van Tendeloo G, Microscopy and microanalysis 15, 464 (2009). http://doi.org/10.1017/S1431927609093957
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Impact Factor: 1.891
Times cited: 1
DOI: 10.1017/S1431927609093957
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“Fiber bundle description of flow and nonlinear hydrodynamics on circles”. Ludu A, Journal of nonlinear mathematical physics 15, 157 (2008). http://doi.org/10.2991/jnmp.2008.15.s2.11
Abstract: We introduce a differential geometry description of the path lines, stream lines and particles contours in hydrodynamics. We present a generalized form of a Korteweg-de Vries type of equation for the exterior of a circle. Nonlinearities from the boundary conditions, surface tension and the Euler equations are taken into account, but the flow is considered inviscid and irrotational. For the circular case we describe the traveling waves shapes, solitons and the particles trajectories.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 0.986
Times cited: 1
DOI: 10.2991/jnmp.2008.15.s2.11
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“Nanoscale insight into silk-like protein self-assembly: effect of design and number of repeat units”. Razzokov J, Naderi S, van der Schoot P, Physical biology 15, 066010 (2018). http://doi.org/10.1088/1478-3975/aadb5e
Abstract: By means of replica exchange molecular dynamics simulations we investigate how the length of a silk-like, alternating diblock oligopeptide influences its secondary and quaternary structure. We carry out simulations for two protein sizes consisting of three and five blocks, and study the stability of a single protein, a dimer, a trimer and a tetramer. Initial configurations of our simulations are β-roll and β-sheet structures. We find that for the triblock the secondary and quaternary structures upto and including the tetramer are unstable: the proteins melt into random coil structures and the aggregates disassemble either completely or partially. We attribute this to the competition between conformational entropy of the proteins and the formation of hydrogen bonds and hydrophobic interactions between proteins. This is confirmed by our simulations on the pentablock proteins, where we find that, as the number of monomers in the aggregate increases, individual monomers form more hydrogen bonds whereas their solvent accessible surface area decreases. For the pentablock β-sheet protein, the monomer and the dimer melt as well, although for the β-roll protein only the monomer melts. For both trimers and tetramers remain stable. Apparently, for these the entropy loss of forming β-rolls and β-sheets is compensated for in the free-energy gain due to the hydrogen-bonding and hydrophobic interactions. We also find that the middle monomers in the trimers and tetramers are conformationally much more stable than the ones on the top and the bottom. Interestingly, the latter are more stable on the tetramer than on the trimer, suggesting that as the number of monomers increases protein-protein interactions cooperatively stabilize the assembly.
According to our simulations, the β-roll and β-sheet aggregates must be approximately equally
stable.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Times cited: 1
DOI: 10.1088/1478-3975/aadb5e
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“Real-time tilt undersampling optimization during electron tomography of beam sensitive samples using golden ratio scanning and RECAST3D”. Craig TM, Kadu AA, Batenburg KJ, Bals S, Nanoscale 15, 5391 (2023). http://doi.org/10.1039/D2NR07198C
Abstract: Electron tomography is a widely used technique for 3D structural analysis of nanomaterials, but it can cause damage to samples due to high electron doses and long exposure times. To minimize such damage, researchers often reduce beam exposure by acquiring fewer projections through tilt undersampling. However, this approach can also introduce reconstruction artifacts due to insufficient sampling. Therefore, it is important to determine the optimal number of projections that minimizes both beam exposure and undersampling artifacts for accurate reconstructions of beam-sensitive samples. Current methods for determining this optimal number of projections involve acquiring and post-processing multiple reconstructions with different numbers of projections, which can be time-consuming and requires multiple samples due to sample damage. To improve this process, we propose a protocol that combines golden ratio scanning and quasi-3D reconstruction to estimate the optimal number of projections in real-time during a single acquisition. This protocol was validated using simulated and realistic nanoparticles, and was successfully applied to reconstruct two beam-sensitive metal–organic framework complexes.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 6.7
Times cited: 1
DOI: 10.1039/D2NR07198C
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“Quantum wavefront shaping with a 48-element programmable phase plate for electrons”. Yu CP, Vega Ibañez F, Béché, A, Verbeeck J, SciPost Physics 15, 223 (2023). http://doi.org/10.21468/SciPostPhys.15.6.223
Abstract: We present a 48-element programmable phase plate for coherent electron waves produced by a combination of photolithography and focused ion beam. This brings the highly successful concept of wavefront shaping from light optics into the realm of electron optics and provides an important new degree of freedom to prepare electron quantum states. The phase plate chip is mounted on an aperture rod placed in the C2 plane of a transmission electron microscope operating in the 100-300 kV range. The phase plate's behavior is characterized by a Gerchberg-Saxton algorithm, showing a phase sensitivity of 0.075 rad/mV at 300 kV, with a phase resolution of approximately 3x10e−3π. In addition, we provide a brief overview of possible use cases and support it with both simulated and experimental results.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT)
Impact Factor: 5.5
Times cited: 1
DOI: 10.21468/SciPostPhys.15.6.223
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“Pressure as an additional control handle for non-thermal atmospheric plasma processes”. Belov I, Paulussen S, Bogaerts A, Plasma processes and polymers 14, 1700046 (2017). http://doi.org/10.1002/ppap.201700046
Abstract: above atmospheric) pressure regimes (1–3.5 bar). It was demonstrated that these operational conditions significantly influence both the discharge dynamics and the process efficiencies of O2 and CO2 discharges. For the case of the O2 DBD, the pressure rise results in the amplification of the discharge current, the appearance of emission lines of the metal electrode material (Fe, Cr, Ni) in the optical emission spectrum and the formation of a granular film of the erosion products (10–300 nm iron oxide nanoparticles) on the reactor walls. Somewhat similar behavior was observed also for the CO2 DBD. The discharge current, the relative intensity of the CO Angstrom band measured by Optical Emission Spectroscopy (OES) and the CO2 conversion rates could be stimulated to some extent by the rise in pressure. The optimal conditions for the O2 DBD (P = 2 bar) and the CO2 DBD (P = 1.5 bar) are demonstrated. It can be argued that the dynamics of the microdischarges (MD) define the underlying process of this behavior. It could be
demonstrated that the pressure increase stimulates the formation of more intensive but fewer MDs. In this way, the operating pressure can represent an additional tool to manipulate the properties of the MDs in a DBD, and as a result also the discharge performance.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.846
Times cited: 1
DOI: 10.1002/ppap.201700046
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“Quantitatively linking morphology and optical response of individual silver nanohedra”. Wang Y, Sztranyovszky Z, Zilli A, Albrecht W, Bals S, Borri P, Langbein W, Nanoscale 14, 11028 (2022). http://doi.org/10.1039/D2NR02131E
Abstract: The optical response of metal nanoparticles is governed by plasmonic resonances, which are dictated by the particle morphology. A thorough understanding of the link between morphology and optical response requires quantitatively measuring optical and structural properties of the same particle. Here we present such a study, correlating electron tomography and optical micro-spectroscopy. The optical measurements determine the scattering and absorption cross-section spectra in absolute units, and electron tomography determines the 3D morphology. Numerical simulations of the spectra for the individual particle geometry, and the specific optical set-up used, allow for a quantitative comparison including the cross-section magnitude. Silver nanoparticles produced by photochemically driven colloidal synthesis, including decahedra, tetrahedra and bi-tetrahedra are investigated. A mismatch of measured and simulated spectra is found in some cases when assuming pure silver particles, which is explained by the presence of a few atomic layers of tarnish on the surface, not evident in electron tomography. The presented method tightens the link between particle morphology and optical response, supporting the predictive design of plasmonic nanomaterials.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 6.7
Times cited: 1
DOI: 10.1039/D2NR02131E
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“Low-cost electron detector for scanning electron microscope”. Vlasov E, Denisov N, Verbeeck J, HardwareX 14, e00413 (2023). http://doi.org/10.1016/j.ohx.2023.e00413
Abstract: Electron microscopy is an indispensable tool for the characterization of (nano) materials. Electron microscopes are typically very expensive and their internal operation is often shielded from the user. This situation can provide fast and high quality results for researchers focusing on e.g. materials science if they have access to the relevant instruments. For researchers focusing on technique development, wishing to test novel setups, however, the high entry price can lead to risk aversion and deter researchers from innovating electron microscopy technology further. The closed attitude of commercial entities about how exactly the different parts of electron microscopes work, makes it even harder for newcomers in this field. Here we propose an affordable, easy-to-build electron detector for use in a scanning electron microscope (SEM). The aim of this project is to shed light on the functioning of such detectors as well as show that even a very modest design can lead to acceptable performance while providing high flexibility for experimentation and customization.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 1
DOI: 10.1016/j.ohx.2023.e00413
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“Absence of a pressure gap and atomistic mechanism of the oxidation of pure Co nanoparticles”. Vijayakumar J, Savchenko TM, Bracher DM, Lumbeeck G, Béché, A, Verbeeck J, Vajda Š, Nolting F, Vaz Caf, Kleibert A, Nature communications 14, 174 (2023). http://doi.org/10.1038/s41467-023-35846-0
Abstract: Understanding chemical reactivity and magnetism of 3<italic>d</italic>transition metal nanoparticles is of fundamental interest for applications in fields ranging from spintronics to catalysis. Here, we present an atomistic picture of the early stage of the oxidation mechanism and its impact on the magnetism of Co nanoparticles. Our experiments reveal a two-step process characterized by (i) the initial formation of small CoO crystallites across the nanoparticle surface, until their coalescence leads to structural completion of the oxide shell passivating the metallic core; (ii) progressive conversion of the CoO shell to Co<sub>3</sub>O<sub>4</sub>and void formation due to the nanoscale Kirkendall effect. The Co nanoparticles remain highly reactive toward oxygen during phase (i), demonstrating the absence of a pressure gap whereby a low reactivity at low pressures is postulated. Our results provide an important benchmark for the development of theoretical models for the chemical reactivity in catalysis and magnetism during metal oxidation at the nanoscale.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 16.6
Times cited: 1
DOI: 10.1038/s41467-023-35846-0
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“Preventing cation intermixing enables 50% quantum yield in sub-15 nm short-wave infrared-emitting rare-earth based core-shell nanocrystals”. Arteaga Cardona F, Jain N, Popescu R, Busko D, Madirov E, Arús BA, Gerthsen D, De Backer A, Bals S, Bruns OT, Chmyrov A, Van Aert S, Richards BS, Hudry D, Nature communications 14, 4462 (2023). http://doi.org/10.1038/s41467-023-40031-4
Abstract: Short-wave infrared (SWIR) fluorescence could become the new gold standard in optical imaging for biomedical applications due to important advantages such as lack of autofluorescence, weak photon absorption by blood and tissues, and reduced photon scattering coefficient. Therefore, contrary to the visible and NIR regions, tissues become translucent in the SWIR region. Nevertheless, the lack of bright and biocompatible probes is a key challenge that must be overcome to unlock the full potential of SWIR fluorescence. Although rare-earth-based core-shell nanocrystals appeared as promising SWIR probes, they suffer from limited photoluminescence quantum yield (PLQY). The lack of control over the atomic scale organization of such complex materials is one of the main barriers limiting their optical performance. Here, the growth of either homogeneous (α-NaYF<sub>4</sub>) or heterogeneous (CaF<sub>2</sub>) shell domains on optically-active α-NaYF<sub>4</sub>:Yb:Er (with and without Ce<sup>3+</sup>co-doping) core nanocrystals is reported. The atomic scale organization can be controlled by preventing cation intermixing only in heterogeneous core-shell nanocrystals with a dramatic impact on the PLQY. The latter reached 50% at 60 mW/cm<sup>2</sup>; one of the highest reported PLQY values for sub-15 nm nanocrystals. The most efficient nanocrystals were utilized for in vivo imaging above 1450 nm.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 16.6
Times cited: 1
DOI: 10.1038/s41467-023-40031-4
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“Plasma processes and polymers third special issue on plasma and cancer”. Laroussi M, Bogaerts A, Barekzi N, Plasma processes and polymers 13, 1142 (2016). http://doi.org/10.1002/ppap.201600193
Keywords: Editorial; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.846
Times cited: 1
DOI: 10.1002/ppap.201600193
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“Metal-polymer heterojunction in colloidal-phase plasmonic catalysis”. Rogolino A, Claes N, Cizaurre J, Marauri A, Jumbo-Nogales A, Lawera Z, Kruse J, Sanroman-Iglesias M, Zarketa I, Calvo U, Jimenez-Izal E, Rakovich YP, Bals S, Matxain JM, Grzelczak M, The journal of physical chemistry letters 13, 2264 (2022). http://doi.org/10.1021/ACS.JPCLETT.1C04242
Abstract: Plasmonic catalysis in the colloidal phase requires robust surface ligands that prevent particles from aggregation in adverse chemical environments and allow carrier flow from reagents to nanoparticles. This work describes the use of a water-soluble conjugated polymer comprising a thiophene moiety as a surface ligand for gold nanoparticles to create a hybrid system that, under the action of visible light, drives the conversion of the biorelevant NAD+ to its highly energetic reduced form NADH. A combination of advanced microscopy techniques and numerical simulations revealed that the robust metal-polymer heterojunction, rich in sulfonate functional groups, directs the interaction of electron-donor molecules with the plasmonic photocatalyst. The tight binding of polymer to the gold surface precludes the need for conventional transition-metal surface cocatalysts, which were previously shown to be essential for photocatalytic NAD(+) reduction but are known to hinder the optical properties of plasmonic nanocrystals. Moreover, computational studies indicated that the coating polymer fosters a closer interaction between the sacrificial electron-donor triethanolamine and the nanoparticles, thus enhancing the reactivity.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 5.7
Times cited: 1
DOI: 10.1021/ACS.JPCLETT.1C04242
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“Electronic structure of the valence band in cylindrical strained InP/InGaP quantum dots in an external magnetic field”. Tadic, Peeters FM, Physica. E: Low-dimensional systems and nanostructures
T2 –, 14th International Conference on the Electronic Properties of, Two-Dimensional Systems, July 30-August 03, 2001, Prague, Czech Republic 12, 880 (2002). http://doi.org/10.1016/S1386-9477(01)00445-3
Abstract: The multiband effective-mass model of cylindrical self-assembled quantum dots in a magnetic field normal to the layer of the quantum dots is presented. The strain distribution is computed by the valence force field method. The strain-dependent multiband Hamiltonian is modified into an axially symmetric form, which commutes with the total angular momentum F-2 = fh. where f denotes the total magnetic quantum number. The heavy hole and the light hole parts in the mixed hole state are resolved. It is found that the heavy hole component dominates in the ground states for both f = 1/2 and 3/2. The electronic structure exhibits numerous anticrossings between the hole levels. The Zeeman splitting between the +\f\ and -\f\ states is also computed. (C) 2002 Elsevier Science B.V. All rights reserved.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.221
Times cited: 1
DOI: 10.1016/S1386-9477(01)00445-3
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“Symmetry-adapted rotator functions for molecules in cylindrical confinement”. Verberck B, International journal of molecular sciences 12, 317 (2011). http://doi.org/10.3390/ijms12010317
Abstract: We present a general description of the formalism of symmetry-adapted rotator functions (SARFs) for molecules in cylindrical confinement. Molecules are considered as clusters of interaction centers (ICs), can have any symmetry, and can display different types of ICs. Cylindrical confinement can be realized by encapsulation in a carbon nanotube (CNT). The potential energy of a molecule surrounded by a CNT can be calculated by evaluating a limited number of terms of an expansion into SARFs, which offers a significant reduction of the computation time. Optimal molecular orientations can be deduced from the resulting potential energy landscape. Examples, including the case of a molecule with cubic symmetry inside a CNT, are discussed.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.226
Times cited: 1
DOI: 10.3390/ijms12010317
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“Inverse heavy-atom effect in near infrared photoluminescent gold nanoclusters”. Pramanik G, Kvakova K, Thottappali MA, Rais D, Pfleger J, Greben M, El-Zoka A, Bals S, Dracinsky M, Valenta J, Cigler P, Nanoscale 12, 10462 (2021). http://doi.org/10.1039/D1NR90138A
Abstract: Fluorophores functionalized with heavy elements show enhanced intersystem crossing due to increased spin-orbit coupling, which in turn shortens the fluorescence decay lifetime (tau(PL)). This phenomenon is known as the heavy-atom effect (HAE). Here, we report the observation of increased tau(PL) upon functionalisation of near-infrared photoluminescent gold nanoclusters with iodine. The heavy atom-mediated increase in tau(PL) is in striking contrast with the HAE and referred to as inverse HAE. Femtosecond and nanosecond transient absorption spectroscopy revealed overcompensation of a slight decrease in lifetime of the transition associated with the Au core (ps) by a large increase in the long-lived triplet state lifetime associated with the Au shell, which contributed to the observed inverse HAE. This unique observation of inverse HAE in gold nanoclusters provides the means to enhance the triplet excited state lifetime.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 7.367
Times cited: 1
DOI: 10.1039/D1NR90138A
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“Formation of a nanoscale SiO2 capping layer on photoresist lines with an Ar/SiCl4/O2 inductively coupled plasma : a modeling investigation”. Tinck S, Altamirano-Sánchez E, De Schepper P, Bogaerts A, Plasma processes and polymers 11, 52 (2014). http://doi.org/10.1002/ppap.201300062
Abstract: PECVD of a nanoscale SiO2 capping layer using low pressure SiCl4/O-2/Ar plasmas is numerically investigated. The purpose of this capping layer is to restore photoresist profiles with improved line edge roughness. A 2D plasma and Monte Carlo feature profile model are applied for this purpose. The deposited films are calculated for various operating conditions to obtain a layer with desired shape. An increase in pressure results in more isotropic deposition with a higher deposition rate, while a higher power creates a more anisotropic process. Dilution of the gas mixture with Ar does not result in an identical capping layer shape with a thickness linearly correlated to the dilution. Finally, a substrate bias seems to allow proper control of the vertical deposition rate versus sidewall deposition as desired.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.846
Times cited: 1
DOI: 10.1002/ppap.201300062
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“Nanoscale inhomogeneities in melt-spun Ni-Al”. Potapov P, Ochin P, Pons J, Schryvers D, Journal de physique: 4 11, 439 (2001). http://doi.org/10.1051/jp4:2001873
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 1
DOI: 10.1051/jp4:2001873
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“Structural characterisation of melt-spun Ti-Ni-Cu-ribbons”. Schryvers D, Potapov P, Ledda A, Shelyakov A, Journal de physique: 4 11, 363 (2001). http://doi.org/10.1051/jp4:2001861
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 1
DOI: 10.1051/jp4:2001861
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“Surface Functionalization of Grown-on-Tip ZnO Nanopyramids: From Fabrication to Light-Triggered Applications”. Gasparotto A, Maccato C, Carraro G, Sada C, Štangar UL, Alessi B, Rocks C, Mariotti D, La Porta A, Altantzis T, Barreca D, Acs Applied Materials &, Interfaces 11, 15881 (2019). http://doi.org/10.1021/acsami.8b22744
Abstract: We report on a combined chemical vapor deposition (CVD)/radio frequency (RF) sputtering synthetic strategy for the controlled surface modification of ZnO nanostructures by Ti-containing species. Specifically, the proposed approach consists in the CVD of grown-on-tip ZnO nanopyramids, followed by titanium RF sputtering under mild conditions. The results obtained by a thorough characterization demonstrate the successful ZnO surface functionalization with dispersed Ti-containing species in low amounts. This phenomenon, in turn, yields a remarkable enhancement of photoactivated superhydrophilic behavior, self-cleaning ability, and photocatalytic performances in comparison to bare ZnO. The reasons accounting for such an improvement are unravelled by a multitechnique analysis, elucidating the interplay between material chemico-physical properties and the corresponding functional behavior. Overall, the proposed strategy stands as an amenable tool for the mastering of semiconductor-based functional nanoarchitectures through ad hoc engineering of the system surface.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 7.504
Times cited: 1
DOI: 10.1021/acsami.8b22744
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“Synergistic Effects of Melittin and Plasma Treatment: A Promising Approach for Cancer Therapy”. Shaw P, Kumar N, Hammerschmid D, Privat-Maldonado A, Dewilde S, Bogaerts A, Cancers 11, 1109 (2019). http://doi.org/10.3390/cancers11081109
Abstract: Melittin (MEL), a small peptide component of bee venom, has been reported to exhibit anti-cancer effects in vitro and in vivo. However, its clinical applicability is disputed because of its non-specific cytotoxicity and haemolytic activity in high treatment doses. Plasma-treated phosphate buffered saline solution (PT-PBS), a solution rich in reactive oxygen and nitrogen species (RONS) can disrupt the cell membrane integrity and induce cancer cell death through oxidative stress-mediated pathways. Thus, PT-PBS could be used in combination with MEL to facilitate its access into cancer cells and to reduce the required therapeutic dose. The aim of our study is to determine the reduction of the effective dose of MEL required to eliminate cancer cells by its combination with PT-PBS. For this purpose, we have optimised the MEL threshold concentration and tested the combined treatment of MEL and PT-PBS on A375 melanoma and MCF7 breast cancer cells, using in vitro, in ovo and in silico approaches. We investigated the cytotoxic effect of MEL and PT-PBS alone and in combination to reveal their synergistic cytological effects. To support the in vitro and in ovo experiments, we showed by computer simulations that plasma-induced oxidation of the phospholipid bilayer leads to a decrease of the free energy barrier for translocation of MEL in comparison with the non-oxidized bilayer, which also suggests a synergistic effect of MEL with plasma induced oxidation. Overall, our findings suggest that MEL in combination with PT-PBS can be a promising combinational therapy to circumvent the non-specific toxicity of MEL, which may help for clinical applicability in the future.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Times cited: 1
DOI: 10.3390/cancers11081109
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“Transformations of supported gold nanoparticles observed by in situ electron microscopy”. Liu P, Wu T, Madsen J, Schiotz J, Wagner JB, Hansen TW, Nanoscale 11, 11885 (2019). http://doi.org/10.1039/C9NR02731A
Abstract: Oxide supported metal nanoparticles play an important role in heterogeneous catalysis. However, understanding the metal/oxide interface and their evolution under reaction conditions remains challenging. Herein, we investigate the interface between Au nanoparticles and a CeO2 substrate by environmental transmission electron microscopy with atomic resolution. We find that the Au nanoparticles have two preferential epitaxial relationships with the substrate, i.e. Type I (111)[-110]CeO2//(111)[-110]Au and Type II (111)[-110]CeO2//(111)[1-10]Au orientation relationships, where Type I is preferred. In situ observations in the presence of O-2 show that the gas can stimulate the supported Au nanoparticles to transform between these two orientations even at room temperature. Moreover, when increasing the temperature to 973 K, the transformation of an Au nanoparticle between the two orientation states and a non-crystalline state in the presence of O-2 is also observed. DFT calculations of the binding between Au and CeO2 in the two relationships are strongly influenced by the presence of oxygen vacancies. For a given position of a vacancy, there is a significant energy difference between the energy of the two types. However, for some positions, Type I is preferred, and for others, Type II, but the most favourable position of the vacancy for the two types has a very similar energy. This is consistent with the observation of both types of adhesion.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 7.367
Times cited: 1
DOI: 10.1039/C9NR02731A
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