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“Atomic resolution mapping of phonon excitations in STEM-EELS experiments”. Egoavil R, Gauquelin N, Martinez GT, Van Aert S, Van Tendeloo G, Verbeeck J, Ultramicroscopy 147, 1 (2014). http://doi.org/10.1016/j.ultramic.2014.04.011
Abstract: Atomically resolved electron energy-loss spectroscopy experiments are commonplace in modern aberration-corrected transmission electron microscopes. Energy resolution has also been increasing steadily with the continuous improvement of electron monochromators. Electronic excitations however are known to be delocalized due to the long range interaction of the charged accelerated electrons with the electrons in a sample. This has made several scientists question the value of combined high spatial and energy resolution for mapping interband transitions and possibly phonon excitation in crystals. In this paper we demonstrate experimentally that atomic resolution information is indeed available at very low energy losses around 100 meV expressed as a modulation of the broadening of the zero loss peak. Careful data analysis allows us to get a glimpse of what are likely phonon excitations with both an energy loss and gain part. These experiments confirm recent theoretical predictions on the strong localization of phonon excitations as opposed to electronic excitations and show that a combination of atomic resolution and recent developments in increased energy resolution will offer great benefit for mapping phonon modes in real space.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 22
DOI: 10.1016/j.ultramic.2014.04.011
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“Graphane”. Sahin H, Leenaerts O, Singh SK, Peeters FM, Wiley Interdisciplinary Reviews: Computational Molecular Science 5, 255 (2015). http://doi.org/10.1002/wcms.1216
Abstract: Atomically thin crystals have recently been the focus of attention, in particular, after the synthesis of graphene, a monolayer hexagonal crystal structure of carbon. In this novel material class, the chemically derived graphenes have attracted tremendous interest. It was shown that, although bulk graphite is a chemically inert material, the surface of single layer graphene is rather reactive against individual atoms. So far, synthesis of several graphene derivatives have been reported such as hydrogenated graphene graphane' (CH), fluorographene (CF), and chlorographene (CCl). Moreover, the stability of bromine and iodine covered graphene were predicted using computational tools. Among these derivatives, easy synthesis, insulating electronic behavior and reversibly tunable crystal structure of graphane make this material special for future ultra-thin device applications. This overview surveys structural, electronic, magnetic, vibrational, and mechanical properties of graphane. We also present a detailed overview of research efforts devoted to the computational modeling of graphane and its derivatives. Furthermore recent progress in synthesis techniques and possible applications of graphane are reviewed as well. WIREs Comput Mol Sci 2015, 5:255-272. doi: 10.1002/wcms.1216 For further resources related to this article, please visit the . Conflict of interest: The authors have declared no conflicts of interest for this article.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 14.016
Times cited: 54
DOI: 10.1002/wcms.1216
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“Isolating hydrogen in hexagonal boron nitride bubbles by a plasma treatment”. He L, Wang H, Chen L, Wang X, Xie H, Jiang C, Li C, Elibol K, Meyer J, Watanabe K, Taniguchi T, Wu Z, Wang W, Ni Z, Miao X, Zhang C, Zhang D, Wang H, Xie X, Nature communications 10, 2815 (2019). http://doi.org/10.1038/s41467-019-10660-9
Abstract: Atomically thin hexagonal boron nitride (h-BN) is often regarded as an elastic film that is impermeable to gases. The high stabilities in thermal and chemical properties allow h-BN to serve as a gas barrier under extreme conditions. Here, we demonstrate the isolation of hydrogen in bubbles of h-BN via plasma treatment. Detailed characterizations reveal that the substrates do not show chemical change after treatment. The bubbles are found to withstand thermal treatment in air, even at 800°C. Scanning transmission electron microscopy investigation shows that the h-BN multilayer has a unique aligned porous stacking nature, which is essential for the character of being transparent to atomic hydrogen but impermeable to hydrogen molecules. In addition, we successfully demonstrated the extraction of hydrogen gases from gaseous compounds or mixtures containing hydrogen element. The successful production of hydrogen bubbles on h-BN flakes has potential for further application in nano/ micro-electromechanical systems and hydrogen storage.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 12.124
Times cited: 8
DOI: 10.1038/s41467-019-10660-9
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“Nanoribbons: From fundamentals to state-of-the-art applications”. Yagmurcukardes M, Peeters FM, Senger RT, Sahin H, Applied physics reviews 3, 041302 (2016). http://doi.org/10.1063/1.4966963
Abstract: Atomically thin nanoribbons (NRs) have been at the forefront of materials science and nanoelectronics in recent years. State-of-the-art research on nanoscale materials has revealed that electronic, magnetic, phononic, and optical properties may differ dramatically when their one-dimensional forms are synthesized. The present article aims to review the recent advances in synthesis techniques and theoretical studies on NRs. The structure of the review is organized as follows: After a brief introduction to low dimensional materials, we review different experimental techniques for the synthesis of graphene nanoribbons (GNRs) with their advantages and disadvantages. In addition, theoretical investigations on width and edge-shape-dependent electronic and magnetic properties, functionalization effects, and quantum transport properties of GNRs are reviewed. We then devote time to the NRs of the transition metal dichalcogenides (TMDs) family. First, various synthesis techniques, E-field-tunable electronic and magnetic properties, and edge-dependent thermoelectric performance of NRs of MoS2 and WS2 are discussed. Then, strongly anisotropic properties, growth-dependent morphology, and the weakly width-dependent bandgap of ReS2 NRs are summarized. Next we discuss TMDs having a T-phase morphology such as TiSe2 and stable single layer NRs of mono-chalcogenides. Strong edge-type dependence on characteristics of GaS NRs, width-dependent Seebeck coefficient of SnSe NRs, and experimental analysis on the stability of ZnSe NRs are reviewed. We then focus on the most recently emerging NRs belonging to the class of transition metal trichalcogenides which provide ultra-high electron mobility and highly anisotropic quasi-1D properties. In addition, width-, edge-shape-, and functionalization-dependent electronic and mechanical properties of blackphosphorus, a monoatomic anisotropic material, and studies on NRs of group IV elements (silicene, germanene, and stanene) are reviewed. Observation of substrate-independent quantum well states, edge and width dependent properties, the topological phase of silicene NRs are reviewed. In addition, H-2 concentration-dependent transport properties and anisotropic dielectric function of GeNRs and electric field and strain sensitive I-V characteristics of SnNRs are reviewed. We review both experimental and theoretical studies on the NRs of group III-V compounds. While defect and N-termination dependent conductance are highlighted for boron nitride NRs, aluminum nitride NRs are of importance due to their dangling bond, electric field, and strain dependent electronic and magnetic properties. Finally, superlattice structure of NRs of GaN/AlN, Si/Ge, G/BN, and MoS2/WS2 is reviewed. Published by AIP Publishing.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 13.667
Times cited: 63
DOI: 10.1063/1.4966963
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“Optical versus electron diffraction imaging of Twist-angle in 2D transition metal dichalcogenide bilayers”. Psilodimitrakopoulos S, Orekhov A, Mouchliadis L, Jannis D, Maragkakis GM, Kourmoulakis G, Gauquelin N, Kioseoglou G, Verbeeck J, Stratakis E, npj 2D Materials and Applications 5, 77 (2021). http://doi.org/10.1038/S41699-021-00258-5
Abstract: Atomically thin two-dimensional (2D) materials can be vertically stacked with van der Waals bonds, which enable interlayer coupling. In the particular case of transition metal dichalcogenide (TMD) bilayers, the relative direction between the two monolayers, coined as twist-angle, modifies the crystal symmetry and creates a superlattice with exciting properties. Here, we demonstrate an all-optical method for pixel-by-pixel mapping of the twist-angle with a resolution of 0.55(degrees), via polarization-resolved second harmonic generation (P-SHG) microscopy and we compare it with four-dimensional scanning transmission electron microscopy (4D STEM). It is found that the twist-angle imaging of WS2 bilayers, using the P-SHG technique is in excellent agreement with that obtained using electron diffraction. The main advantages of the optical approach are that the characterization is performed on the same substrate that the device is created on and that it is three orders of magnitude faster than the 4D STEM. We envisage that the optical P-SHG imaging could become the gold standard for the quality examination of TMD superlattice-based devices.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Times cited: 4
DOI: 10.1038/S41699-021-00258-5
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“Free energy barriers from biased molecular dynamics simulations”. Bal KM, Fukuhara S, Shibuta Y, Neyts EC, Journal Of Chemical Physics 153, 114118 (2020). http://doi.org/10.1063/5.0020240
Abstract: Atomistic simulation methods for the quantification of free energies are in wide use. These methods operate by sampling the probability density of a system along a small set of suitable collective variables (CVs), which is, in turn, expressed in the form of a free energy surface (FES). This definition of the FES can capture the relative stability of metastable states but not that of the transition state because the barrier height is not invariant to the choice of CVs. Free energy barriers therefore cannot be consistently computed from the FES. Here, we present a simple approach to calculate the gauge correction necessary to eliminate this inconsistency. Using our procedure, the standard FES as well as its gauge-corrected counterpart can be obtained by reweighing the same simulated trajectory at little additional cost. We apply the method to a number of systems—a particle solvated in a Lennard-Jones fluid, a Diels–Alder reaction, and crystallization of liquid sodium—to demonstrate its ability to produce consistent free energy barriers that correctly capture the kinetics of chemical or physical transformations, and discuss the additional demands it puts on the chosen CVs. Because the FES can be converged at relatively short (sub-ns) time scales, a free energy-based description of reaction kinetics is a particularly attractive option to study chemical processes at more expensive quantum mechanical levels of theory.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.4
DOI: 10.1063/5.0020240
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“Graphene nanoribbons subjected to axial stress”. Neek-Amal M, Peeters FM, Physical review : B : condensed matter and materials physics 82, 085432 (2010). http://doi.org/10.1103/PhysRevB.82.085432
Abstract: Atomistic simulations are used to study the bending of rectangular graphene nanoribbons subjected to axial stress both for free boundary and supported boundary conditions. The shapes of the deformations of the buckled graphene nanoribbons, for small values of the stress, are sine waves where the number of nodal lines depend on the longitudinal size of the system and the applied boundary condition. The buckling strain for the supported boundary condition is found to be independent of the longitudinal size and estimated to be 0.86%. From a calculation of the free energy at finite temperature we find that the equilibrium projected two-dimensional area of the graphene nanoribbon is less than the area of a flat sheet. At the optimum length the boundary strain for the supported boundary condition is 0.48%.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 92
DOI: 10.1103/PhysRevB.82.085432
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“Direct observation of realistic-temperature fuel combustion mechanisms in atomistic simulations”. Bal KM, Neyts EC, Chemical science 7, 5280 (2016). http://doi.org/10.1039/C6SC00498A
Abstract: Atomistic simulations can in principle provide an unbiased description of all mechanisms, intermediates, and products of complex chemical processes. However, due to the severe time scale limitation of conventional simulation techniques, unrealistically high simulation temperatures are usually applied, which are a poor approximation of most practically relevant low-temperature applications. In this work, we demonstrate the direct observation at the atomic scale of the pyrolysis and oxidation of n-dodecane at temperatures as low as 700 K through the use of a novel simulation technique, collective variable-driven hyperdynamics (CVHD). A simulated timescale of up to 39 seconds is reached. Product compositions and dominant mechanisms are found to be strongly temperature-dependent, and are consistent with experiments and kinetic models. These simulations provide a first atomic-level look at the full dynamics of the complicated fuel combustion process at industrially relevant temperatures and time scales, unattainable by conventional molecular dynamics simulations.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 8.668
Times cited: 22
DOI: 10.1039/C6SC00498A
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“Transport of hydrogen isotopes through interlayer spacing in van der Waals crystals”. Hu S, Gopinadhan K, Rakowski A, Neek-Amal M, Heine T, Grigorieva IV, Haigh SJ, Peeters FM, Geim AK, Lozada-Hidalgo M, Nature nanotechnology 13, 468 (2018). http://doi.org/10.1038/S41565-018-0088-0
Abstract: Atoms start behaving as waves rather than classical particles if confined in spaces commensurate with their de Broglie wavelength. At room temperature this length is only about one angstrom even for the lightest atom, hydrogen. This restricts quantum-confinement phenomena for atomic species to the realm of very low temperatures(1-5). Here, we show that van der Waals gaps between atomic planes of layered crystals provide angstrom-size channels that make quantum confinement of protons apparent even at room temperature. Our transport measurements show that thermal protons experience a notably higher barrier than deuterons when entering van der Waals gaps in hexagonal boron nitride and molybdenum disulfide. This is attributed to the difference in the de Broglie wavelengths of the isotopes. Once inside the crystals, transport of both isotopes can be described by classical diffusion, albeit with unexpectedly fast rates comparable to that of protons in water. The demonstrated angstrom-size channels can be exploited for further studies of atomistic quantum confinement and, if the technology can be scaled up, for sieving hydrogen isotopes.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 38.986
Times cited: 32
DOI: 10.1038/S41565-018-0088-0
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“Three-dimensional atomic structure of supported Au nanoparticles at high temperature”. Liu P, Arslan Irmak E, De Backer A, De wael A, Lobato I, Béché, A, Van Aert S, Bals S, Nanoscale 13 (2021). http://doi.org/10.1039/D0NR08664A
Abstract: Au nanoparticles (NPs) deposited on CeO2 are extensively used as thermal catalysts since the morphology of the NPs is expected to be stable at elevated temperatures. Although it is well known that the activity of Au NPs depends on their size and surface structure, their three-dimensional (3D) structure at the atomic scale has not been completely characterized as a function of temperature. In this paper, we overcome the limitations of conventional electron tomography by combining atom counting applied to aberration-corrected scanning transmission electron microscopy images and molecular dynamics relaxation. In this manner, we are able to perform an atomic resolution 3D investigation of supported Au NPs. Our results enable us to characterize the 3D equilibrium structure of single NPs as a function of temperature. Moreover, the dynamic 3D structural evolution of the NPs at high temperatures, including surface layer jumping and crystalline transformations, has been studied.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 7.367
Times cited: 13
DOI: 10.1039/D0NR08664A
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“Au particles supported on (110) anatase-TiO2”. Giorgio S, Henry CR, Pauwels B, Van Tendeloo G, Microstructure And Processing 297, 197 (2001). http://doi.org/10.1016/S0921-5093(00)01261-2
Abstract: Au particles were prepared by evaporation in ultra high vacuum at high temperature, on the surfaces of TiO2 micro-spheres with the anatase structure. The morphology and the structural deformation in Au deposits were studied by high resolution transmission electron microscopy and image simulations by the multislice technique. The particles were polyhedral, limited by (100) and (111) faces. Patches with a hexagonal lattice were found around the particles, which was interpreted as thin Au islands on the surface. In these islands the Au lattice was deformed and perfectly accommodated to the (110) surface of TiO2. (C) 2001 Elsevier Science B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.094
Times cited: 40
DOI: 10.1016/S0921-5093(00)01261-2
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“Auger electron emission initiated by the creation of valence-band holes in graphene by positron annihilation”. Chirayath VA, Callewaert V, Fairchild AJ, Chrysler MD, Gladen RW, Mcdonald AD, Imam SK, Shastry K, Koymen AR, Saniz R, Barbiellini B, Rajeshwar K, Partoens B, Weiss AH, Nature communications 8, 16116 (2017). http://doi.org/10.1038/ncomms16116
Abstract: Auger processes involving the filling of holes in the valence band are thought to make important contributions to the low-energy photoelectron and secondary electron spectrum from many solids. However, measurements of the energy spectrum and the efficiency with which electrons are emitted in this process remain elusive due to a large unrelated background resulting from primary beam-induced secondary electrons. Here, we report the direct measurement of the energy spectra of electrons emitted from single layer graphene as a result of the decay of deep holes in the valence band. These measurements were made possible by eliminating competing backgrounds by employing low-energy positrons (<1.25 eV) to create valence-band holes by annihilation. Our experimental results, supported by theoretical calculations, indicate that between 80 and 100% of the deep valence-band holes in graphene are filled via an Auger transition.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 12.124
Times cited: 20
DOI: 10.1038/ncomms16116
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“Optimization of Automated Crystal Orientation Mapping in a TEM for Ni4Ti3 Precipitation in All-Round SMA”. Yao X, Amin-Ahmadi B, Li Y, Cao S, Ma X, Zhang X-P, Schryvers D, Shape memory and superelasticity 2, 286 (2016). http://doi.org/10.1007/s40830-016-0082-z
Abstract: Automated crystal orientation and phase mapping in TEM are applied to the quantification of Ni4Ti3 precipitates in Ni–Ti shape memory alloys which will be used for the implantation of artificial sphincters operating using the all-round shape memory effect. This paper focuses on the optimization process of the technique to obtain best values for all major parameters in the acquisition of electron diffraction patterns as well as template generation. With the obtained settings, vast statistical data on nano- and microstructures essential to the operation of these shape memory devices become available.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 2
DOI: 10.1007/s40830-016-0082-z
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“Geochemistry of suspended matter from the baltic sea : 1 : results of individual particle characterization by automated electron microprobe”. Bernard PC, Van Grieken RE, Brügmann L, Marine chemistry 26, 155 (1989). http://doi.org/10.1016/0304-4203(89)90058-3
Abstract: Automated electron probe X-ray microanalysis was used to characterize some 15 000 individual suspension particles from 50 samples of suspended matter collected from different depths at 18 stations throughout the Baltic Sea and the transient area to the North Sea. For each particle, 14 minor and major elements were determined and size information data were obtained. To process this huge amount of results, multivariate analysis techniques were invoked: the particles were classified into specific types and the abundance variations of these groups were studied. It appeared that 80% of all investigated particles contained mostly silicon, and seemed to consist of quartz, and K-rich and Fe-rich aluminosilicates. The abundance of BaSO4 particles averaged 5% throughout the Baltic Sea, but amounted to up to 44% at some stations. The abundance of the Fe-rich particles varied significantly with location and depth, and averaged ∼ 4%. They were often found to be associated with significant amounts of P. Both of these particle types and the Mn-rich particles are thought to be mainly authigenic. Calcium carbonate particles are more abundant towards the North Sea (which seems to act as a source). Principal component analysis of the data revealed that most of the compositional variability can be explained by differences between deep and surface waters and by the influences of inflowing North Sea waters. Additional information about the types and sources of the suspended matter in the Baltic Sea was gained from the comparison and correlation of the single particle results with different fractions of the bulk concentrations of elements such as Al, Ca, Mn, Fe, Zn and Ba.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/0304-4203(89)90058-3
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“Sulfur-based denitrification treating regeneration water from ion exchange at high performance and low cost”. Vandekerckhove TGL, Kobayashi K, Janda J, Van Nevel S, Vlaeminck SE, Bioresource technology 257, 266 (2018). http://doi.org/10.1016/J.BIORTECH.2018.02.047
Abstract: Autotrophic denitrification with sulfur is an underexplored alternative to heterotrophic denitrification to remove nitrate from wastewater poor in organics. The application on ion exchange regeneration water (19.432.1 mS cm−1) is novel. Three fixed bed reactors were tested at 15 °C for >4 months, inoculated with activated sludge from sewage treatment. All were fast in start-up (<10 days) with high performance (94 ± 2% removal efficiency). pH control with NaOH rendered higher nitrate removal rates than limestone addition to the bed (211 ± 13 vs. 102 ± 13 mg N L−1 d−1), related to higher pH (6.64 vs. 6.24) and sulfur surface area. Bacterial communities were strongly enriched in Sulfurimonas (6367%) and Thiobacillus (2426%). In an economic comparison, sulfur-based denitrification (5.3 kg−1 N) was 15% cheaper than methanol-based denitrification (6.22 kg−1 N) and both treatments were opex dominated (85.9 vs. 86.5%). Overall, the technological and economic feasibility should boost further implementation of sulfurotrophic denitrification.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1016/J.BIORTECH.2018.02.047
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“Boron structure evolution in magnetic Cr₂O₃, thin films”. Sun C, Street M, Zhang C, Van Tendeloo G, Zhao W, Zhang Q, Materials Today Physics 27, 100753 (2022). http://doi.org/10.1016/J.MTPHYS.2022.100753
Abstract: B substituting O in antiferromagnetic Cr2O3 is known to increase the Ne ' el temperature, whereas the actual B dopant site and the corresponding functionality remains unclear due to the complicated local structure. Herein, A combination of electron energy loss spectroscopy and first-principles calculations were used to unveil B local structures in B doped Cr2O3 thin films. B was found to form either magnetic active BCr4 tetrahedra or various inactive BO3 triangles in the Cr2O3 lattice, with a* and z* bonds exhibiting unique spectral features. Identification of BO3 triangles was achieved by changing the electron momentum transfer to manipulate the differential cross section for the 1s-z* and 1s-a* transitions. Modeling the experimental spectra as a linear combination of simulated B K edges reproduces the experimental z* / a* ratios for 15-42% of the B occupying the active BCr4 structure. This result is further supported by first-principles based thermodynamic calculations.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 11.5
DOI: 10.1016/J.MTPHYS.2022.100753
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“Coverage determinants of breast cancer screening in Flanders : an evaluation of the past decade”. Ding L, Jidkova S, Greuter MJW, Van Herck K, Goossens M, Martens P, de Bock GH, Van Hal G, International journal for equity in health 19, 212 (2020). http://doi.org/10.1186/S12939-020-01323-Z
Abstract: Background Breast cancer (BC) is the most common cancer in women in the developed world. In order to find developing cancers in an early stage, BC screening is commonly used. In Flanders, screening is performed in and outside an organized breast cancer screening program (BCSP). However, the determinants of BC screening coverage for both screening strategies are yet unknown. Objective To assess the determinants of BC screening coverage in Flanders. Methods Reimbursement data were used to attribute a screening status to each woman in the target population for the years 2008-2016. Yearly coverage data were categorized as screening inside or outside BCSP or no screening. Data were clustered by municipality level. A generalized linear equation model was used to assess the determinants of screening type. Results Over all years and municipalities, the median screening coverage rate inside and outside BCSP was 48.40% (IQR: 41.50-54.40%) and 14.10% (IQR: 9.80-19.80%) respectively. A higher coverage rate outside BSCP was statistically significantly (P < 0.001) associated with more crowded households (OR: 3.797, 95% CI: 3.199-4.508), younger age, higher population densities (OR: 2.528, 95% CI: 2.455-2.606), a lower proportion of unemployed job seekers (OR: 0.641, 95% CI: 0.624-0.658) and lower use of dental care (OR: 0.969, 95% CI: 0.967-0.972). Conclusion Coverage rate of BC screening is not optimal in Flanders. Women with low SES that are characterized by younger age, living in a high population density area, living in crowded households, or having low dental care are less likely to be screened for BC in Flanders. If screened, they are more likely to be screened outside the BCSP.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Social Epidemiology & Health Policy (SEHPO)
DOI: 10.1186/S12939-020-01323-Z
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“Reporter gene-expressing bone marrow-derived stromal cells are immune-tolerated following implantation in the central nervous system of syngeneic immunocompetent mice”. Bergwerf I, de Vocht N, Tambuyzer B, Verschueren J, Reekmans K, Daans J, Ibrahimi A, Van Tendeloo V, Chatterjee S, Goossens H, Jorens PG, Baekelandt V, Ysebaert D, Van Marck E, Berneman ZN, Van Der Linden A, Ponsaerts P, BMC biotechnology (2009). http://doi.org/10.1186/1472-6750-9-1
Abstract: Background Cell transplantation is likely to become an important therapeutic tool for the treatment of various traumatic and ischemic injuries to the central nervous system (CNS). However, in many pre-clinical cell therapy studies, reporter gene-assisted imaging of cellular implants in the CNS and potential reporter gene and/or cell-based immunogenicity, still remain challenging research topics. Results In this study, we performed cell implantation experiments in the CNS of immunocompetent mice using autologous (syngeneic) luciferase-expressing bone marrow-derived stromal cells (BMSC-Luc) cultured from ROSA26-L-S-L-Luciferase transgenic mice, and BMSC-Luc genetically modified using a lentivirus encoding the enhanced green fluorescence protein (eGFP) and the puromycin resistance gene (Pac) (BMSC-Luc/eGFP/Pac). Both reporter gene-modified BMSC populations displayed high engraftment capacity in the CNS of immunocompetent mice, despite potential immunogenicity of introduced reporter proteins, as demonstrated by real-time bioluminescence imaging (BLI) and histological analysis at different time-points post-implantation. In contrast, both BMSC-Luc and BMSC-Luc/eGFP/Pac did not survive upon intramuscular cell implantation, as demonstrated by real-time BLI at different time-points post-implantation. In addition, ELISPOT analysis demonstrated the induction of IFN-ã-producing CD8+ T-cells upon intramuscular cell implantation, but not upon intracerebral cell implantation, indicating that BMSC-Luc and BMSC-Luc/eGFP/Pac are immune-tolerated in the CNS. However, in our experimental transplantation model, results also indicated that reporter gene-specific immune-reactive T-cell responses were not the main contributors to the immunological rejection of BMSC-Luc or BMSC-Luc/eGFP/Pac upon intramuscular cell implantation. Conclusion We here demonstrate that reporter gene-modified BMSC derived from ROSA26-L-S-L-Luciferase transgenic mice are immune-tolerated upon implantation in the CNS of syngeneic immunocompetent mice, providing a research model for studying survival and localisation of autologous BMSC implants in the CNS by real-time BLI and/or histological analysis in the absence of immunosuppressive therapy.
Keywords: A1 Journal article; Antwerp Surgical Training, Anatomy and Research Centre (ASTARC); Laboratory Experimental Medicine and Pediatrics (LEMP); Bio-Imaging lab; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.415
Times cited: 33
DOI: 10.1186/1472-6750-9-1
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“INTER-ACT : prevention of pregnancy complications through an e-health driven interpregnancy lifestyle intervention: study protocol of a multicentre randomised controlled trial”. Bogaerts A, Ameye L, Bijlholt M, Amuli K, Heynickx D, Devlieger R, BMC pregnancy and childbirth 17, 154 (2017). http://doi.org/10.1186/S12884-017-1336-2
Abstract: Background Excessive maternal pre-pregnancy and gestational weight gain are related to pregnancy- and birth outcomes. The interpregnancy time window offers a unique opportunity to intervene in order to acquire a healthy lifestyle before the start of a new pregnancy. Methods INTER-ACT is an e-health driven multicentre randomised controlled intervention trial targeting women at high risk of pregnancy- and birth related complications. Eligible women are recruited for the study at day 2 or 3 postpartum. At week 6 postpartum, participants are randomised into the intervention or control arm of the study. The intervention focuses on weight, diet, physical activity and mental well-being, and comprises face-to-face coaching, in which behavioural change techniques are central, and use of a mobile application, which is Bluetooth-connected to a weighing scale and activity tracker. The intervention is rolled out postpartum (4 coaching sessions between week 6 and month 6) and in a new pregnancy (3 coaching sessions, one in each trimester of pregnancy); the mobile app is used throughout the two intervention phases. Data collection includes data from the medical record of the participants (pregnancy outcomes and medical history), anthropometric data (height, weight, waist- and hip circumferences, skinfold thickness and body composition by bio-electrical impedance analysis), data from the mobile app (physical activity and weight; intervention group only) and questionnaires (socio-demographics, breastfeeding, food intake, physical activity, lifestyle, psychosocial factors and process evaluation). Medical record data are collected at inclusion and at delivery of the subsequent pregnancy. All other data are collected at week 6 and month 6 postpartum and every subsequent 6 months until a new pregnancy, and in every trimester in the new pregnancy. Primary outcome is the composite endpoint score of pregnancy-induced hypertension, gestational diabetes mellitus, caesarean section, and large-for-gestational-age infant in the subsequent pregnancy.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Centre for Research and Innovation in Care (CRIC)
Impact Factor: 2.263
Times cited: 4
DOI: 10.1186/S12884-017-1336-2
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“Monitoring the laccase reaction of vanillin and poplar hydrolysate”. Sóti V, Jacquet N, Apers S, Richel A, Lenaerts S, Cornet I, Journal of chemical technology and biotechnology 91, 1914 (2016). http://doi.org/10.1002/JCTB.4789
Abstract: BACKGROUND Laccase is an intensively researched enzyme for industrial use. Except for decolorisation measurements, HPLC analysis is the conventional method for monitoring the phenolic removal during laccase enzyme reaction. This paper reports an investigation of the continuous UV absorbance follow-up of the laccase reaction with steam pretreated poplar hydrolysate. RESULTS Vanillin was used as a model substrate and lignocellulose xylose rich fraction (XRF) as a biologically complex substrate for laccase detoxification. The reaction was followed by HPLC-UV as well as by UV spectrometric measurements. Results suggest that the reaction can be successfully monitored by measuring the change of UV absorbance at 280 nm, without previous compound separation. In case of XRF experiments the spectrophotometric follow-up is especially useful, as HPLC analysis takes a long time and provides less information than in case of single substrates. The method seems to be suitable for optimization and process control. CONCLUSION The obtained results can help to construct a fast, easy and straightforward monitoring system for laccase-phenolic substrate reactions.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL); Biochemical Wastewater Valorization & Engineering (BioWaVE)
Impact Factor: 3.135
Times cited: 3
DOI: 10.1002/JCTB.4789
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“Effects of salinity, pH and growth phase on the protein productivity by Dunaliella salina”. Sui Y, Vlaeminck SE, Journal of chemical technology and biotechnology 94, 1032 (2019). http://doi.org/10.1002/JCTB.5850
Abstract: BACKGROUND Microalgae have long been adopted for use as human food, animal feed and high‐value products. For carotenogenesis, Dunaliella salina is one of the most studied microalgae, yet its protein synthesis has been limitedly reported. In this study, D. salina was cultivated at different NaCl and pH levels to optimize its protein productivity. RESULTS The biomass protein content followed an increasedecrease pattern throughout the growth phases, with a maximum in the exponential phase (6080% over ash‐free dry weight). Adversely, the biomass pigment contents were at relatively stable levels (around 0.5% carotenoids, 1.3% chlorophyll a and 0.5% chlorophyll b over ash‐free dry weight). Among the tested conditions (13 mol L−1 salinity, pH 7.59.5), the highest protein productivity (43.5 mg L−1 day−1) was achieved at 2 mol L−1 salinity and pH 7.5 during the exponential phase, which surpassed others by 1697%. Additionally, table salts were tested to be equivalent and cost‐efficient salt sources for the growth medium. CONCLUSION This study highlighted the suitability of D. salina as a protein source, providing guidelines for 70% cheaper medium formulation in the lab and for maximum protein productivity at larger scale.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1002/JCTB.5850
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“OrBITS : label-free and time-lapse monitoring of patient derived organoids for advanced drug screening”. Deben C, Cardenas De La Hoz E, Le Compte M, Van Schil P, Hendriks JMH, Lauwers P, Yogeswaran SK, Lardon F, Pauwels P, van Laere S, Bogaerts A, Smits E, Vanlanduit S, Lin A, Cellular Oncology (2211-3428) , 1 (2022). http://doi.org/10.1007/S13402-022-00750-0
Abstract: Background Patient-derived organoids are invaluable for fundamental and translational cancer research and holds great promise for personalized medicine. However, the shortage of available analysis methods, which are often single-time point, severely impede the potential and routine use of organoids for basic research, clinical practise, and pharmaceutical and industrial applications. Methods Here, we developed a high-throughput compatible and automated live-cell image analysis software that allows for kinetic monitoring of organoids, named Organoid Brightfield Identification-based Therapy Screening (OrBITS), by combining computer vision with a convolutional network machine learning approach. The OrBITS deep learning analysis approach was validated against current standard assays for kinetic imaging and automated analysis of organoids. A drug screen of standard-of-care lung and pancreatic cancer treatments was also performed with the OrBITS platform and compared to the gold standard, CellTiter-Glo 3D assay. Finally, the optimal parameters and drug response metrics were identified to improve patient stratification. Results OrBITS allowed for the detection and tracking of organoids in routine extracellular matrix domes, advanced Gri3D (R)-96 well plates, and high-throughput 384-well microplates, solely based on brightfield imaging. The obtained organoid Count, Mean Area, and Total Area had a strong correlation with the nuclear staining, Hoechst, following pairwise comparison over a broad range of sizes. By incorporating a fluorescent cell death marker, infra-well normalization for organoid death could be achieved, which was tested with a 10-point titration of cisplatin and validated against the current gold standard ATP-assay, CellTiter-Glo 3D. Using this approach with OrBITS, screening of chemotherapeutics and targeted therapies revealed further insight into the mechanistic action of the drugs, a feature not achievable with the CellTiter-Glo 3D assay. Finally, we advise the use of the growth rate-based normalised drug response metric to improve accuracy and consistency of organoid drug response quantification. Conclusion Our findings validate that OrBITS, as a scalable, automated live-cell image analysis software, would facilitate the use of patient-derived organoids for drug development and therapy screening. The developed wet-lab workflow and software also has broad application potential, from providing a launching point for further brightfield-based assay development to be used for fundamental research, to guiding clinical decisions for personalized medicine.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Antwerp Surgical Training, Anatomy and Research Centre (ASTARC); Center for Oncological Research (CORE)
Impact Factor: 6.6
DOI: 10.1007/S13402-022-00750-0
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“Enhanced carbon and nitrogen removal performance of simultaneous anammox and denitrification (SAD) with mannitol addition treating saline wastewater”. Yang Z, Zhu W, Yu D, Bo Y, Li J, Journal of chemical technology and biotechnology 94, 377 (2019). http://doi.org/10.1002/JCTB.5781
Abstract: BACKGROUND Simultaneous anammox and denitrification (SAD) can remove carbon and nitrogen. However, its performance is suppressed under saline surroundings. In this work, mannitol was used to enhance a SAD process treating saline wastewater. RESULTS The optimum carbon and nitrogen removal was achieved at 0.2 mmol L-1 mannitol, during which ammonium removal efficiency (ARE), nitrite removal efficiency (NRE) and chemical oxygen demand (COD) removal efficiency were 96.95%, 93.70% and 90.05%, respectively. The maximum ammonium removal rate (ARR), nitrite removal rate (NRR) and the specific anammox activity (SAA) were increased by 25.49%, 55.84% and 33.83% with optimum addition (0.2 mmol L-1 mannitol) respectively. The diameter of sludge was enlarged with the addition of mannitol (<= 0.2 mmol L-1). The Tseng-Wayman model was more suitable to simulate the whole SAD process. The modified logistic model, the modified Boltzman model and the modified Gompertz model were all appropriate to describe nitrogen removal in a typical cycle with the addition of mannitol. CONCLUSION Mannitol was effective in enhancing a SAD process treating saline wastewater, and maximum nitrogen removal was achieved at mannitol = 0.2 mmol L-1. The Tseng-Wayman model satisfactorily predicted the whole SAD process treating saline wastewater with mannitol addition. (c) 2018 Society of Chemical Industry
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1002/JCTB.5781
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“Electrochemical detection of Toxocara canis excretory-secretory antigens in children from rural communities in Esmeraldas Province, Ecuador : association between active infection and high eosinophilia”. Morales-Yánez F, Trashin S, Sariego I, Roucher C, Paredis L, Chico M, De Wael K, Muyldermans S, Cooper P, Polman K, Parasites &, Vectors 13, 245 (2020). http://doi.org/10.1186/S13071-020-04113-2
Abstract: Background The diagnosis of active Toxocara canis infections in humans is challenging. Larval stages of T. canis do not replicate in human tissues and disease may result from infection with a single T. canis larva. Recently, we developed a nanobody-based electrochemical magnetosensor assay with superior sensitivity to detect T. canis excretory-secretory (TES) antigens. Here, we evaluate the performance of the assay in children from an Ecuadorian birth cohort that followed children to five years of age. Methods Samples were selected based on the presence of peripheral blood eosinophilia and relative eosinophil counts. The samples were analyzed by the nanobody-based electrochemical magnetosensor assay, which utilizes a bivalent biotinylated nanobody as capturing agent on the surface of streptavidin pre-coated paramagnetic beads. Detection was performed by a different nanobody chemically labelled with horseradish peroxidase. Results Of 87 samples tested, 33 (38%) scored positive for TES antigen recognition by the electrochemical magnetosensor assay. The average concentration of TES antigen in serum was 2.1 ng/ml (SD = 1.1). The positive result in the electrochemical assay was associated with eosinophilia > 19% (P = 0.001). Parasitological data were available for 57 samples. There was no significant association between positivity by the electrochemical assay and the presence of other soil-transmitted helminth infections. Conclusions Our nanobody-based electrochemical assay provides highly sensitive quantification of TES antigens in serum and has potential as a valuable tool for the diagnosis of active human toxocariasis.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.2
DOI: 10.1186/S13071-020-04113-2
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“Respiratory muscle activity after spontaneous, neostigmine- or sugammadex-enhanced recovery of neuromuscular blockade : a double blind prospective randomized controlled trial”. Schepens T, Janssens K, Maes S, Wildemeersch D, Vellinga J, Jorens PG, Saldien V, BMC anesthesiology 19, 187 (2019). http://doi.org/10.1186/S12871-019-0863-Y
Abstract: Background The use of neostigmine after neuromuscular blockade (NMB) has been associated with postoperative respiratory complications. In previous studies, we found lower diaphragmatic activity after neostigmine reversal of NMB, compared to sugammadex. It is still unclear whether the adequate use of neostigmine guarantees normal respiratory muscle function after NMB. In this study, we wanted to assess the effect of commonly used degrees of NMB and their possible reversal strategies on respiratory muscle activity after the return of normal neuromuscular transmission. Methods This is a randomized, controlled, parallel-group, single-centre, double-blind study in patients scheduled for intracranial surgery at a tertiary academic hospital in Belgium. All participants received target controlled propofol/remifentanil anesthesia and were randomized into one of five groups, receiving either a shallow NMB with no reversal (shallow/saline), a shallow NMB with sugammadex reversal (shallow/sugammadex), a moderate NMB with neostigmine reversal (moderate/neostigmine), a moderate NMB with sugammadex reversal (moderate/sugammadex), or a deep NMB with sugammadex reversal (deep/sugammadex). Primary and secondary outcome parameters were diaphragm and intercostal electromyographic (EMG) activity at the moment of resumed spontaneous breathing activity, defined as a maximal interval of 10 min after the first spontaneous breath. Results For the five groups, a total of 55 patients could be included in the final analysis. Median time of spontaneous breathing analyzed was 5 min (IQR 3-9.5 min). Both the moderate/sugammadex and the moderate/neostigmine groups had lower levels of diaphragm EMG compared to the shallow/sugammadex group. The moderate/neostigmine group had lower levels of intercostal EMG activity compared to the shallow/saline group. Conclusions In this study, the depth of neuromuscular blockade and type of reversal strategy impacts respiratory muscle activity at the moment of resumed spontaneous breathing and recovery of neuromuscular blockade. Both groups that received moderate NMB had lower levels of diaphragm EMG, compared to the shallow NMB group with sugammadex reversal. Compared to the shallow NMB group with no reversal, the moderate NMB with neostigmine reversal group had lower intercostal EMG activity.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Surgical Training, Anatomy and Research Centre (ASTARC); Laboratory Experimental Medicine and Pediatrics (LEMP)
Impact Factor: 1.525
DOI: 10.1186/S12871-019-0863-Y
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“Auranofin repurposing for lung and pancreatic cancer : low CA12 expression as a marker of sensitivity in patient-derived organoids, with potentiated efficacy by AKT inhibition”. Deben C, Freire Boullosa L, Rodrigues Fortes F, Cardenas De La Hoz E, Le Compte M, Seghers S, Peeters M, Vanlanduit S, Lin A, Dijkstra KK, Van Schil P, Hendriks JMH, Prenen H, Roeyen G, Lardon F, Smits E, Journal of Experimental and Clinical Cancer Research 43, 88 (2024). http://doi.org/10.1186/S13046-024-03012-Z
Abstract: Background This study explores the repurposing of Auranofin (AF), an anti-rheumatic drug, for treating non-small cell lung cancer (NSCLC) adenocarcinoma and pancreatic ductal adenocarcinoma (PDAC). Drug repurposing in oncology offers a cost-effective and time-efficient approach to developing new cancer therapies. Our research focuses on evaluating AF's selective cytotoxicity against cancer cells, identifying RNAseq-based biomarkers to predict AF response, and finding the most effective co-therapeutic agents for combination with AF. Methods Our investigation employed a comprehensive drug screening of AF in combination with eleven anticancer agents in cancerous PDAC and NSCLC patient-derived organoids (n = 7), and non-cancerous pulmonary organoids (n = 2). Additionally, we conducted RNA sequencing to identify potential biomarkers for AF sensitivity and experimented with various drug combinations to optimize AF's therapeutic efficacy. Results The results revealed that AF demonstrates a preferential cytotoxic effect on NSCLC and PDAC cancer cells at clinically relevant concentrations below 1 µM, sparing normal epithelial cells. We identified Carbonic Anhydrase 12 (CA12) as a significant RNAseq-based biomarker, closely associated with the NF-κB survival signaling pathway, which is crucial in cancer cell response to oxidative stress. Our findings suggest that cancer cells with low CA12 expression are more susceptible to AF treatment. Furthermore, the combination of AF with the AKT inhibitor MK2206 was found to be particularly effective, exhibiting potent and selective cytotoxic synergy, especially in tumor organoid models classified as intermediate responders to AF, without adverse effects on healthy organoids. Conclusion Our research offers valuable insights into the use of AF for treating NSCLC and PDAC. It highlights AF's cancer cell selectivity, establishes CA12 as a predictive biomarker for AF sensitivity, and underscores the enhanced efficacy of AF when combined with MK2206 and other therapeutics. These findings pave the way for further exploration of AF in cancer treatment, particularly in identifying patient populations most likely to benefit from its use and in optimizing combination therapies for improved patient outcomes.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Antwerp Surgical Training, Anatomy and Research Centre (ASTARC); Center for Oncological Research (CORE)
DOI: 10.1186/S13046-024-03012-Z
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“A real-world analysis on the efficacy and tolerability of liposomal irinotecan plus 5-fluorouracil and folinic acid in metastatic pancreatic ductal adenocarcinoma in Belgium”. Verbruggen L, Verheggen L, Vanhoutte G, Loly C, Lybaert W, Borbath I, Vergauwe P, Hendrickx K, Debeuckelaere C, de Haar-Holleman A, Van Laethem J-L, Peeters M, Therapeutic advances in medical oncology 15, 1 (2023). http://doi.org/10.1177/17588359231181500
Abstract: Background: Currently, nanoliposomal irinotecan (nal-IRI) + 5-fluorouracil/folinic acid (5-FU/ LV) is the only approved second-line treatment for patients suffering from metastatic pancreatic ductal adenocarcinoma (mPDAC). However, also other chemotherapeutic regimens are used in this setting and due to the lack of clear real-world data on the efficacy of the different regimens, there is no consensus on the optimal treatment sequence for mPDAC patients. Objectives: To provide information on the safe and efficacious use of nal-IRI + 5-FU/LV in clinical practice in Belgium, which is needed for healthcare professionals to estimate the risk-benefit ratio of the intervention. Methods: Medical data of adult patients with mPDAC who were treated with nal-IRI + 5-FU/ LV in one of the participating Belgian hospitals were retrospectively collected. Kaplan-Meier analysis was performed to obtain survival curves to estimate the median overall survival (OS) and progression-free survival (PFS). All other results were presented descriptively. Results: A total of 56 patients [median age at diagnosis: 69 years (range 43 years), 57.1% male] were included. Patients received a median of 5 (range 49 cycles) nal-IRI + 5-FU/LV cycles, extended over 10 weeks (range 130.8 weeks). The median start dose for nal-IRI was 70 mg/ m(2) (range 49.24 mg/m(2)) and chemotherapy dose reduction and delay occurred in, respectively, 42.8% and 37.5% of the patients. The median OS was 6.8 months (95% CI: 5.6-8.4 months) with a 6-month survival rate of 57.4% and a 1-year survival rate of 27.8% in the overall study population. The median OS for patients treated with nal-IRI as second-line therapy or as laterline treatment was, respectively, 6.8 months (95% CI: 5.9-7.0 months) and 5.6 months (95% CI: 4.2-no upper limit). In the overall study population, a median PFS of 3.1 months (95% CI: 2.4-4.6 months) and a disease control rate of 48.3%, comprising 30.4% stable disease, 16.1% partial and 1.8% complete response, was observed. The median PFS for patients treated with nal-IRI as second-line therapy was 3.9 months (95% CI: 2.8-4.8 months) while this was 2.4 months (95% CI: 1.9-9.1 months) for those that received nal-IRI in a later-line treatment. In terms of safety, gastrointestinal problems occurred most (64.3% of the patients) and from all reported treatment emergent adverse events, 39.2% were grade 3 or 4. Conclusion: Nal-IRI + 5-FU/LV is a valuable, effective, and safe sequential treatment option following gemcitabine-based therapy in patients with mPDAC.
Keywords: A1 Journal article; Center for Oncological Research (CORE)
Impact Factor: 4.9
DOI: 10.1177/17588359231181500
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“Novel functional imaging of changes in small airways of patients treated with extrafine beclomethasone/formoterol”. Vos W, de Backer J, Poli G, De Volder A, Ghys L, Van Holsbeke C, Vinchurkar S, De Backer L, de Backer W, Respiration 86, 393 (2013). http://doi.org/10.1159/000347120
Abstract: Background: Inhaled formulations using extrafine particles of long-acting beta(2)-agonists and corticosteroids were developed to optimize asthma treatment. Findings that these combinations reach and treat smaller airways more effectively are predominantly based on general non-specific outcomes with little information on regional characteristics. Objectives: This study aims to assess long-term effects of extrafine beclomethasone/formoterol on small airways of asthmatic patients using novel functional imaging methods. Methods: Twenty-four stable asthma patients were subdivided into three groups (steroid naive, n = 7; partially controlled, n = 6; well controlled, n = 11). Current treatment was switched to a fixed combination of extrafine beclomethasone/formoterol (Foster (R); Chiesi Pharmaceuticals, Parma, Italy). Patients underwent lung function evaluation and thorax high-resolution computerized tomography (HRCT) scan. Local airway resistance was obtained from computational fluid dynamics (CFD). Results: After 6 months, the entire population showed improvement in pre-bronchodilation imaging parameters, including small airway volume (p = 0.0007), resistance (p = 0.011), and asthma control score (p = 0.016). Changes in small airway volume correlated with changes in asthma control score (p = 0.004). Forced expiratory volume in 1 s (p = 0.044) and exhaled nitric oxide (p = 0.040) also improved. Functional imaging provided more detail and clinical relevance compared to lung function tests, especially in the well-controlled group where only functional imaging parameters showed significant improvement, while the correlation with asthma control score remained. Conclusions: Extrafine beclomethasone/formoterol results in a significant reduction of small airway obstruction, detectable by functional imaging (HRCT/CFD). Changes in imaging parameters correlated significantly with clinically relevant improvements. This indicates that functional imaging is a useful tool for sensitive assessment of changes in the respiratory system after asthma treatment. Copyright (C) 2013 S. Karger AG, Basel
Keywords: A1 Journal article; Biophysics and Biomedical Physics; Condensed Matter Theory (CMT); Laboratory Experimental Medicine and Pediatrics (LEMP)
Impact Factor: 2.772
Times cited: 30
DOI: 10.1159/000347120
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“Associations between PM2.5 and heart rate variability are modified by particle composition and beta-blocker use in patients with coronary heart disease”. de Hartog JJ, Lanki T, Timonen KL, Hoek G, Janssen NAH, Ibald-Mulli A, Peters A, Heinrich J, Tarkainen TH, Van Grieken R, van Wijnen JH, Brunekreef B, Pekkanen J, Environmental health perspectives 117, 105 (2009). http://doi.org/10.1289/EHP.11062
Abstract: Background: It has been hypothesized that ambient particulate air pollution is able to modify the autonomic nervous control of the heart, measured as heart rate variability (HRV) . Previously we reported heterogeneous associations between particulate matter with aerodynamic diameter < 2.5 µm (PM2.5) and HRV across three study centers. Objective: We evaluated whether exposure misclassification, effect modification by medication, or differences in particle composition could explain the inconsistencies. Methods: Subjects with coronary heart disease visited clinics biweekly in Amsterdam, the Netherlands ; Erfurt, Germany ; and Helsinki, Finland for 68 months. The standard deviation (SD) of NN intervals on an electrocardiogram (ECG ; SDNN) and high frequency (HF) power of HRV was measured with ambulatory ECG during paced breathing. Outdoor levels of PM2.5 were measured at a central site. In Amsterdam and Helsinki, indoor and personal PM2.5 were measured during the 24 hr preceding the clinic visit. PM2.5 was apportioned between sources using principal component analyses. We analyzed associations of indoor/personal PM2.5, elements of PM2.5, and source-specific PM2.5 with HRV using linear regression. Results: Indoor and personal PM2.5 were not associated with HRV. Increased outdoor PM2.5 was associated with decreased SDNN and HF at lags of 2 and 3 days only among persons not using beta-blocker medication. Traffic-related PM2.5 was associated with decreased SDNN, and long-range transported PM2.5 with decreased SDNN and HF, most strongly among persons not using beta blockers. Indicators for PM2.5 from traffic and long-range transport were also associated with decreased HRV. Conclusions: Our results suggest that differences in the composition of particles, beta-blocker use, and obesity of study subjects may explain some inconsistencies among previous studies on HRV.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1289/EHP.11062
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“Effect of high-dose N-acetylcysteine on airway geometry, inflammation, and oxidative stress in COPD patients”. de Backer J, Vos W, Van Holsbeke C, Vinchurkar S, Claes R, Parizel PM, de Backer W, International Journal Of Chronic Obstructive Pulmonary Disease 8, 569 (2013). http://doi.org/10.2147/COPD.S49307
Abstract: Background: Previous studies have demonstrated the potential beneficial effect of N-acetylcysteine (NAC) in chronic obstructive pulmonary disease (COPD). However, the required dose and responder phenotype remain unclear. The current study investigated the effect of high-dose NAC on airway geometry, inflammation, and oxidative stress in COPD patients. Novel functional respiratory imaging methods combining multislice computed tomography images and computer-based flow simulations were used with high sensitivity for detecting changes induced by the therapy. Methods: Twelve patients with Global Initiative for Chronic Obstructive Lung Disease stage II COPD were randomized to receive NAC 1800 mg or placebo daily for 3 months and were then crossed over to the alternative treatment for a further 3 months. Results: Significant correlations were found between image-based resistance values and glutathione levels after treatment with NAC (P = 0.011) and glutathione peroxidase at baseline (P = 0.036). Image-based resistance values appeared to be a good predictor for glutathione peroxidase levels after NAC (P = 0.02), changes in glutathione peroxidase levels (P = 0.035), and reduction in lobar functional residual capacity levels (P = 0.00084). In the limited set of responders to NAC therapy, the changes in airway resistance were in the same order as changes induced by budesonide/formoterol. Conclusion: A combination of glutathione, glutathione peroxidase, and imaging parameters could potentially be used to phenotype COPD patients who would benefit from addition of NAC to their current therapy. The findings of this small pilot study need to be confirmed in a larger pivotal trial.
Keywords: A1 Journal article; Biophysics and Biomedical Physics; Condensed Matter Theory (CMT); Antwerp Surgical Training, Anatomy and Research Centre (ASTARC); Laboratory Experimental Medicine and Pediatrics (LEMP)
Impact Factor: 3.157
Times cited: 21
DOI: 10.2147/COPD.S49307
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