918 results on '"Wagemans, J"'
Search Results
302. Similarity extraction and modeling
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Van Gool, L., primary, Wagemans, J., additional, Vandeneede, J., additional, and Oosterlinck, A., additional
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303. Review of S.M. Kosslyn, Image and Brain: The Resolution of the Imagery Debate
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Wagemans, J.
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- 1996
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304. Perceptual-cognitive skills in offside decision making: expertise and training effects.
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Catteeuw P, Gilis B, Wagemans J, Helsen W, Catteeuw, Peter, Gilis, Bart, Wagemans, Johan, and Helsen, Werner
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This two-experiment study aims to investigate the role of expertise in offside decision making (Experiment 1) and the effect of perceptual-cognitive training (Experiment 2). In Experiment 1, a video-based offside decision-making task followed by a frame recognition task demonstrated a bias toward flag errors and a forward memory shift for less-successful elite-standard assistant referees that is in line with the predictions from the flash-lag effect. In Experiment 2, an offside decision-making training program demonstrated a substantial progress from pre- to posttest for response accuracy, but not for accuracy of memory in the frame recognition task. In both experiments, no differences were found for visual scan patterns. First, these results suggest that less-successful elite-standard assistant referees are more affected by the flash-lag effect. Second, an off-field perceptual-cognitive training program can help assistant referees to deal with the perceptual consequences of the flash-lag illusion and to readjust their decision-making process accordingly. [ABSTRACT FROM AUTHOR]
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- 2010
305. Computational and Psychophysical Mechanisms of Visual Coding; M. Jenkin, L. Harris (Eds.); Cambridge University Press, New York, 1997, (xi + 361) pages, ISBN 0-521-57104-9
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Wagemans, J
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- 1999
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306. Study of Reactor Core Loading Monitoring at the GUINEVERE Facility.
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Bailly, A., Lecouey, J.-L., Billebaud, A., Chabod, S., Kochetkov, A., Krása, A., Lecolley, F.-R., Lehaut, G., Marie, N., Messaoudi, N., Vittiglio, G., and Wagemans, J.
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NUCLEAR reactor cores , *NUCLEAR research , *MONTE Carlo method , *FISSION counters , *NUCLEAR fusion - Abstract
The potential use of a pulsed neutron source (PNS) to measure reactivity during nuclear fuel loading as a means to prevent core loading errors has been studied at the GUINEVERE facility. This facility couples the deuteron accelerator GENEPI-3C to the fast neutron subcritical reactor VENUS-F at the Belgian Nuclear Research Center SCK·CEN. The 14-MeV neutrons are produced in the reactor core center via T (d , n) 4 H e fusion reactions. PNS experiments were performed in five reactor configurations corresponding to the different loading steps of VENUS-F. The evolution of the neutron flux during these PNS experiments was measured by several 235U fission chambers in various positions in the inner and outer reflector and analyzed using the area-ratio method. The results show that, despite strong spatial effects, a strong correlation between the reactivity values given by the area-ratio method and some reference reactivity values remains throughout the reactor unloading. Monte Carlo simulations were first validated by comparison with the data and then used to investigate the sensitivity of the method to a core loading error. First results show that some loading errors could be experimentally detected using a PNS. [ABSTRACT FROM AUTHOR]
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- 2023
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307. Deep Subcriticality Determination Using the Source Jerk Integral Method in the SALMON Program.
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Kochetkov, A., Krása, A., Messaoudi, N., Vittiglio, G., Wagemans, J., Bailly, A., Billebaud, A., Chabod, S., Lecolley, F.-R., Lecouey, J.-L., Lehaut, G., and Marie, N.
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ACCELERATOR-driven systems , *MONTE Carlo method , *NEUTRON sources , *SALMON , *CORRECTION factors , *ACCELERATOR mass spectrometry - Abstract
The Source Jerk Integral (SJI) method has been extensively used to determine the subcriticality in VENUS-F zero-power experiments since 2012. The obtained results were in the range from −5 $ to about −20 $ and concerned the subcriticalities of accelerator-driven system MYRRHA mockup cores. Within the SALMON program, which is dedicated to the safe loading procedure of pressurized power reactors, five subcritical core configurations were assembled and studied in the VENUS-F reactor in 2019. These cores simulated the loading process in inverse mode: from more reactive to deep subcritical. The subcriticality of five variants of the SC11 VENUS-F core was changed in steps from −20 $ to about −100 $ by replacing the fuel assemblies with lead reflector assemblies. The subcriticality levels were determined with the pulsed neutron source (PNS) and SJI methods. The GENEPI-3C deuterium accelerator coupled with VENUS-F was used as an external neutron source. The results of the measurements obtained with the SJI method are presented in this paper. Time-dependent Monte Carlo calculations were performed to simulate the SJI experiments and to determine spatial-energy correction factors. Static Monte Carlo simulations were performed to calculate neutron spectra and reactivity. The results of the measurements (both SJI and PNS) are compared with the static MCNP calculations. [ABSTRACT FROM AUTHOR]
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- 2023
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308. Back to the Roots: Agrobacterium-Specific Phages Show Potential to Disinfect Nutrient Solution from Hydroponic Greenhouses.
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Fortuna, K. J., Holtappels, D., Venneman, J., Baeyen, S., Vallino, M., Verwilt, P., Rediers, H., De Coninck, B., Maes, M., Van Vaerenbergh, J., Lavigne, R., and Wagemans, J.
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HYDROPONICS , *SOILBORNE plant pathogens , *ROOT diseases , *BELL pepper , *AGROBACTERIUM , *WATER pollution , *GREENHOUSES , *BACTERIOPHAGES - Abstract
Agrobacterium biovar 1 is a soilborne plant pathogen with the ability to colonize the irrigation system of greenhouses, causing hairy root disease (HRD). Currently, management focuses on using hydrogen peroxide to disinfect the nutrient solution, but due to the emergence of resistant strains, its efficacy and sustainability are questioned. Using a relevant collection of pathogenic Agrobacterium biovar 1 strains, OLIVR1 to 6, six phages specific to this pathogen and belonging to three different genera were isolated from Agrobacterium biovar 1-infected greenhouses. All phages were named OLIVR, referring to their location of isolation, Onze-Lieve-Vrouwe-Waver, and were characterized by whole-genome analysis, confirming their strictly lytic lifestyle. They remained stable under greenhouse-relevant conditions. To assess the efficacy of the phages, their ability to disinfect greenhouse nutrient solution inoculated with agrobacteria was tested. Each of the phages infected their host, but their ability to decrease the bacterial concentration differed. For instance, OLIVR1 reduced the bacterial concentration with 4 log units without phage resistance emerging. While OLIVR4 and OLIVR5 were also infectious in nutrient solution, they did not always decrease the bacterial load below the limit of detection, and phage resistance emerged. Finally, the mutations causing phage resistance by receptor modification were identified. For OLIVR4-resistant Agrobacterium isolates, but not for OLIVR5-resistant isolates, motility decreased. Together, these data show the potential of some of these phages as disinfectant of nutrient solution, and they might be a valuable tool to tackle HRD. IMPORTANCE: Hairy root disease, caused by rhizogenic Agrobacterium biovar 1 is a rapidly emerging bacterial disease worldwide. It affects tomatoes, cucumbers, eggplant, and bell pepper, causing high yield losses in hydroponic greenhouses. Recent findings suggest that the current management practices, mainly focusing on UV-C and hydrogen peroxide to disinfect contaminated water, have a questionable efficacy. Hence, we investigate the potential of phages as a biological means of preventing this disease. Using a diverse collection of Agrobacterium biovar 1, we isolated three different phage species that together infect 75% of the collection. Since these phages are strictly lytic, while remaining both stable and infectious under greenhouse-relevant conditions, they might be suitable candidates for biological control. [ABSTRACT FROM AUTHOR]
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- 2023
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309. Isolation, characterization and genome analysis of an orphan phage FoX4 of the new Foxquatrovirus genus.
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Holtappels, D., Fortuna, K. J., Vallino, M., Lavigne, R., and Wagemans, J.
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BACTERIOPHAGES , *BRUSSELS sprouts , *XANTHOMONAS campestris , *ORPHANS , *BACTERIAL cultures , *GENOMES , *XANTHOMONAS - Abstract
The growing interest in the therapeutic application of bacteriophages leads to a drastic increase in the number of sequenced genomes. Luckily, recent insights in phage taxonomy facilitate the classification of phages in a comprehensive and data-driven manner as recently proposed by the International Committee on Taxonomy of Viruses. In this research, we present the taxonomical classification of a novel, narrow host range Xanthomonas phage FoX4, isolated from a Brussels sprouts field in Belgium infested with Xanthomonas campestris pv. campestris. The phage has a limited ability to lyse a bacterial culture, yet adsorbs efficiently to its host. Based on its genome sequence and low similarity to previously described phages, the phage comprises the novel phage genus Foxquatrovirus. [ABSTRACT FROM AUTHOR]
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- 2022
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310. Calibration of Large Photonis Fission Chambers in Standard Neutron Fields of the BR1 Reactor.
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Kochetkov, A., Krasa, A., Borms, L., Malambu, E., Vittiglio, G., Wagemans, J., and Willems, J.
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FISSION counters , *NEUTRON flux , *NEUTRONS , *CALIBRATION , *CORRECTION factors , *NUCLEAR reactors , *RESEARCH reactors - Abstract
Small fission chambers manufactured by Photonis, Reuter-Stokes, CEA, and Centronic are routinely calibrated in standard neutron fields of the BR1 reactor at SCK CEN in Mol, Belgium. Two irradiation fields are available: fast spectrum in the MARK3 convertor and thermal spectrum in the Empty Cavity. In this work, for the first time the calibration procedure of larger fission chambers (Photonis CFUL01 and CFUM21 type) with the deposit length exceeding the length of the convertor is presented. Spatial energy correction factors taking into account the neutron flux shape beyond the convertor and radial gradient of the neutron flux were calculated with MCNP and experimentally validated. The combination of calibration (i.e., effective mass measurement) in fast and thermal irradiation fields allows for determination of the purity of 238U deposit. This is demonstrated on three CFUL01-type fission chambers with purity between 99.8% and 99.998%. [ABSTRACT FROM AUTHOR]
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- 2022
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311. Perceptual wholes can reduce the conscious accessibility of their parts.
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Poljac E, de-Wit L, and Wagemans J
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- 2012
312. Shared neural resources between left and right interlimb coordination skills: The neural substrate of abstract motor representations
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Swinnen, S.P., Vangheluwe, S., Wagemans, J., Coxon, J.P., Goble, D.J., Van Impe, A., Sunaert, S., Peeters, R., and Wenderoth, N.
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MAGNETIC resonance imaging of the brain , *MOTOR cortex , *BRAIN physiology , *BIOLOGICAL neural networks , *CEREBRAL hemispheres , *SCIENTIFIC observation - Abstract
Abstract: Functional magnetic resonance imaging was used to reveal the shared neural resources between movements performed with effectors of the left versus right body side. Prior to scanning, subjects extensively practiced a complex coordination pattern involving cyclical motions of the ipsilateral hand and foot according to a 90° out-of-phase coordination mode. Brain activity associated with this (nonpreferred) coordination pattern was contrasted with pre-existing isodirectional (preferred) coordination to extract the learning-related brain networks. To identify the principal candidates for effector-independent movement encoding, the conjunction of training-related activity for left and right limb coordination was determined. A dominantly left-lateralized parietal-to-(pre)motor activation network was identified, with activation in inferior and superior parietal cortex extending into intraparietal sulcus and activation in the premotor areas, including inferior frontal gyrus (pars opercularis). Similar areas were previously identified during observation of complex coordination skills by expert performers. These parietal-premotor areas are principal candidates for abstract (effector-independent) movement encoding, promoting motor equivalence, and they form the highest level in the action representation hierarchy. [Copyright &y& Elsevier]
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- 2010
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313. Preparation and characterisation of an 39Ar sample and study of the 39Ar(nth,α)36S reaction.
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Goeminne, G., Wagemans, C., Wagemans, J., Köster, U., Geltenbort, P., Denecke, B., Johansson, L., and Pommé, S.
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NUCLEAR reactions , *ION implantation - Abstract
The 39Ar(nth,α)36S reaction has been studied for the first time. A sample containing 2.85×1014 39Ar atoms was produced at the ISOLDE facility at CERN. The number of 39Ar atoms in the layer was determined by measuring the 39Ar β-activity using a primary standardisation method. Subsequently, the sample was irradiated with thermal neutrons at the High Flux Reactor of the Institut Laue–Langevin. An upper limit of 0.29b was obtained for the 39Ar(nth,α)36S reaction cross-section. [Copyright &y& Elsevier]
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- 2002
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314. An 26Al target for (n,p) and (n,α) cross-section measurements
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Ingelbrecht, C., Moens, A., Wagemans, J., Denecke, B., Altzitzoglou, T., and Johnston, P.
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RADIOISOTOPES , *ASTROPHYSICS , *NUCLEOSYNTHESIS - Abstract
The radionuclide 26Al plays an important role in astrophysics. It can be detected via the 1.8 MeV γ-ray it emits, providing information on stellar nucleosynthesis processes using maps of the universe made by γ-ray telescopes. In addition, the decay of 26Al to 26Mg in meteorites producing anomalous 26/24Mg ratios gives clues to the origin of the solar system. New studies of the 26Al(n,p)26Mg and 26Al(n,α)23Na destruction mechanisms required an 26Al target containing significantly more 26Al than that previously used. This target was prepared by molecular plating from isopropanol onto a nickel foil substrate with a yield close to 100%. The total number of 26Al atoms, determined by γ-spectrometry, was (2.6±0.2)×1017, corresponding to 11.2±1.0 μg (expanded uncertainty, coverage factor
k=2 ). The areal density was 0.37 μg/cm2. Measurements of (n,p) and (n,α) cross-sections in a thermal neutron beam exhibited sufficient resolution of the p- and α-peaks to allow detection of a number of new transitions. [Copyright &y& Elsevier]- Published
- 2002
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315. THE APPLICABILITY RANGE OF THE MODIFIED SOURCE MULTIPLICATION (MSM) METHOD TESTED IN THE FAST VENUS-F REACTOR.
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Margulis, M., Blaise, P., Krása, A, Kochetkov, A, Messaoudi, N, Vittiglio, G, and Wagemans, J
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MONTE Carlo method , *THERMAL hydraulics , *NEUTRON transport theory , *NUCLEAR reactor cores , *NUCLEAR fission - Abstract
The MSM method is an experimental technique for determination of reactivity of a sub-critical reactor. It consists of one dynamic measurement followed by two static measurements, which use an extraneous neutron source. For the data analysis, the core averaged kinetic parameters need to be calculated as well as a spatially-dependent correction factor that corrects for the point kinetics approximation. In order to test the range for which the method is valid and to demonstrate the reliability of the correction factor calculations in a fast reactor, a dedicated experimental campaign was performed in the fast lead-bismuth VENUS-F reactor. The reactivity of a dozen of sub-critical configurations was measured with the MSM method using ten 235U fission chambers. The detectors were located at various distances from the active zone and from the extraneous neutron source, leading to a large range of values of a correction factor (calculated with the Monte Carlo MCNP5 code) used in the data analysis. [ABSTRACT FROM AUTHOR]
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- 2021
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316. EXTENDED MSM METHOD TO ESTIMATE THE REACTIVITY OF A SUB-CRITICAL CORE DRIVEN BY AN ACCELERATOR BASED NEUTRON SOURCE.
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Billebaud, A., Lecouey, J.-L., Chevret, T., Chabod, S., Doligez, X., Kochetkov, A., Krása, A., Lecolley, F.-R., Lehaut, G., Marie, N., Messaoudi, N., Uyttenhove, W., Vittiglio, G., Wagemans, J., Bécares, V., Villamarin, D., and Mellier, F.
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NUCLEAR reactor reactivity , *NEUTRON transport theory , *NUCLEAR fission , *NUCLEAR reactor cores , *NUCLEAR counters - Abstract
The Modified Source Multiplication method is used to determine an unknown reactivity level of a reactor from a known one if one has access to the detector counting for both levels when the reactor is fed by a constant neutron source like an Am-Be source. When available, an accelerator driven source, in continuous mode, can be useful as its intensity can be tunable and then adapted to the experimental conditions. However, in that case, the MSM technique must be extended to account for an external source whose intensity, energy and angular distributions can vary from one measurement to another. In this paper, this Modified Multi-Source Multiplication (MMSM) method is applied to measurements done during the FREYA project in the GUINEVERE facility, operated with the GENEPI-3C accelerator providing a mixture of (D,T) and (D,D) neutrons. The monitoring of these sources through the detection of the associated charged particles allows the calculation of the MMSM factors and the estimate of the reactivity values. The results are compared in different configurations with the reactivity obtained with an Am-Be source or in dynamic measurements performed with GENEPI-3C. Their excellent agreement shows the possibility of using such accelerator-based neutron sources for MSM measurements when they are correctly monitored. This is of great interest for deep sub-critical level characterization for which detector count rates per source neutrons might be low. [ABSTRACT FROM AUTHOR]
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- 2021
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317. THE SOURCE JERK INTEGRAL METHOD FOR SUB-CRITICALITY MEASUREMENTS IN ADS.
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Kochetkov, A., Billebaud, A., Chabod, S., Krása, A., Lecolley, F.-R., Lecouey, J.-L., Lehaut, G., Marie, N., Messaoudi, N., Vittiglio, G., and Wagemans, J.
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NUCLEAR reactor cores , *NEUTRON transport theory , *THERMAL hydraulics , *NUCLEAR fission , *MONTE Carlo method - Abstract
Three sub-critical (SC) core configurations were investigated in the VENUS-F zero power reactor coupled with the GENEPI-3C accelerator. The SC10 and SC12 were a mock-up of a MYRRHA start-up core and SC11 represented a more complex MYRRHA core loaded with various types of in-pile-sections. The sub-criticality of 11 variants of these VENUS-F cores was changed in several steps from -6$ down to -30$ using the safety and control rods. Their sub-criticalities were determined with the Source Jerk Integral (SJI) method using 11 fission chambers located all over the reactor. For the data analysis, the 8-group delayed neutron parameters from the JEFF-3.1.2 evaluated nuclear data library were used. Reliability and reproducibility of the experimental results were tested by repeating the measurements, swapping the detectors and varying the accelerator beam intensity, thus changing the detector count rates and verifying the validity of the dead time corrections. The obtained results are compared with MCNP calculations. [ABSTRACT FROM AUTHOR]
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- 2021
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318. Training of perceptual-cognitive skills in offside decision making.
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Catteeuw P, Gilis B, Jaspers A, Wagemans J, Helsen W, Catteeuw, Peter, Gilis, Bart, Jaspers, Arne, Wagemans, Johan, and Helsen, Werner
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This study investigates the effect of two off-field training formats to improve offside decision making. One group trained with video simulations and another with computer animations. Feedback after every offside situation allowed assistant referees to compensate for the consequences of the flash-lag effect and to improve their decision-making accuracy. First, response accuracy improved and flag errors decreased for both training groups implying that training interventions with feedback taught assistant referees to better deal with the flash-lag effect. Second, the results demonstrated no effect of format, although assistant referees rated video simulations higher for fidelity than computer animations. This implies that a cognitive correction to a perceptual effect can be learned also when the format does not correspond closely with the original perceptual situation. Off-field offside decision-making training should be considered as part of training because it is a considerable help to gain more experience and to improve overall decision-making performance. [ABSTRACT FROM AUTHOR]
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- 2010
319. Reactivity monitoring of the accelerator driven VENUS-F subcritical reactor with the "current-to-flux" method.
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Marie, N., Lecouey, J.L., Lehaut, G., Chevret, T., Billebaud, A., Chabod, S., Doligez, X., Kochetkov, A., Krása, A., Lecolley, F.R., Mellier, F., Uyttenhove, W., Vittiglio, G., and Wagemans, J.
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CONTROL elements (Nuclear reactors) , *MONTE Carlo method , *BORON carbides , *NEUTRON sources , *FISSION counters - Abstract
Highlights • The "current-to flux" method for monitoring ADS subcriticality was successfully tested experimentally. • Spatial effects affecting the reactivity estimation can be corrected with Monte Carlo simulations. • The robustness and precision of the correction technique is demonstrated. Abstract In this article, we evaluate the quality and robustness of a method envisaged for the on-line monitoring of the subcriticality of an ADS, called the "current-to flux" (CTF) method. For this evaluation, we performed a dedicated experiment at the GUINEVERE facility. It is hosted at the SCK-CEN and consists of the subcritical VENUS-F reactor coupled to a continuous external neutron source provided by the GENEPI-3C accelerator. During this experiment, the reactor control rods were moved in various patterns, and the subsequent dynamical evolutions of the reactor reactivity were monitored using nine fission chambers (FCs). The space-energy effects that bias the reactivity values are corrected using a procedure based on simulations computed with the Monte Carlo neutron transport code MCNP. We investigate the precision of this correction procedure by comparison with a reactivity value extracted with the beam interruption technique and we demonstrate its insensitivity to the simplifications made on the VENUS-F reactor modeling and to a simulation key parameter such as the boron carbide density filling the control rods. [ABSTRACT FROM AUTHOR]
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- 2019
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320. The neutronic modelling of the VENUS-F critical core experiments with the ERANOS deterministic code (FREYA EU FP7 project).
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Sarotto, M., Kochetkov, A., Krása, A., Bianchini, G., Fabrizio, V., Carta, M., Peluso, V., Vittiglio, G., and Wagemans, J.
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NEUTRONS , *NUCLEAR reactors , *NUCLEAR fission , *NUCLIDES , *RADIAL distribution function - Abstract
The EURATOM FP7 project FREYA was launched in 2011 to support the design and licensing of lead-cooled reactors, by choosing as reference the MYRRHA and ALFRED fast spectrum systems. During the five-year project, a number of critical experiments were conducted in the VENUS-F zero-power reactor with the main aim to validate the neutronic codes adopted for the core design. Five critical core configurations were assembled in VENUS-F: the start-up core, the mock-up dedicated to ALFRED and three layouts simulating the MYRRHA reactor conditions. The ERANOS code system, coupled with the JEFF-3.1 nuclear data library, was one of the tools adopted for the design and characterisation of the experiments. In this paper, the results obtained with the ERANOS deterministic code are compared with the experimental measurements of integral and local parameters, such as: the core reactivity and kinetic parameters, the lead void reactivity worth, the axial and radial distributions of fission rates for the nuclides of major interest, the spectral indexes of important actinides ( e.g. , U 238 , Pu 239 , Np 237 , Am 241 ) respect to U 235 . The comparison between measurements and simulations shows a general good agreement, with some discrepancies for few local parameters that are here discussed. [ABSTRACT FROM AUTHOR]
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- 2018
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321. Effective delayed neutron fraction measurement in the critical VENUS-F reactor using noise techniques
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Wagemans, J. [SCK.CEN, Belgian Nuclear Research Centre (Belgium)]
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- 2015
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322. Vision, High-level Theory of
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Wagemans, J.
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323. Experimental results from the VENUS-F critical reference state for the GUINEVERE accelerator driven system project
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Wagemans, J [SCK.CEN, Belgian Nuclear Research Centre, Boeretang 200, BE-2400 Mol (Belgium)]
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- 2011
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324. Spectral indices measurements using miniature fission chambers at the MINERVE zero-power reactor at CEA using calibration data obtained at the BR1 reactor at SCK.CEN
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Wagemans, J [Belgian Nuclear Research Centre, SCK.CEN, Boeretang 200, 2400 Mol (Belgium)]
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- 2011
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325. Electrophysiological markers of predictive coding in multisensory integration and autism spectrum disorder
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van Laarhoven, T.J.T.M., Vroomen, Jean, Stekelenburg, Jeroen, Geurts, H.M., Talsma, D., Wagemans, J., Swerts, Marc, and Cognitive Neuropsychology
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Autism Spectrum Disorders ,multisensory integration ,ERPs ,predictive coding - Abstract
Publiekssamenvatting De manier waarop we de wereld om ons heen waarnemen is niet alleen gebaseerd op informatie die we via onze zintuigen ontvangen, maar wordt ook gevormd door onze ervaringen uit het verleden. Een recent geïntroduceerde theorie over de verwerking en integratie van sensorische informatie en eerdere ervaringen, de zogeheten predictive coding theorie, gaat ervan uit dat ons brein continu een intern predictiemodel van de wereld om ons heen genereert op basis van informatie die we ontvangen via onze zintuigen en gebeurtenissen die we in het verleden hebben meegemaakt. Het kunnen voorspellen wat we in bepaalde situaties zullen gaan zien, horen, voelen, ruiken en proeven, stelt ons in staat om te anticiperen op sensorische prikkels. Om deze reden reageren we vaak sneller en accurater op voorspelbare sensorische signalen. Op neuraal niveau zijn er ook aanwijzingen gevonden voor de aanwezigheid van een intern predictiemodel. Na het horen van een geluid, bijvoorbeeld van de claxon van een auto, genereert ons brein automatisch elektrische activiteit die met behulp van elektro-encefalografie (EEG) te meten is. Wanneer we datzelfde geluid zelf initiëren, door bijvoorbeeld zelf op de claxon te drukken, kunnen we beter voorspellen wanneer het geluid optreedt en hoe dit ongeveer zal klinken. Deze toename in voorspelbaarheid van het geluid is terug te zien in een vermindering van het EEG signaal. Wanneer we luisteren naar een reeks voorspelbare geluiden waarin onverwacht een geluid wordt weggelaten genereert het brein ook een duidelijk elektrisch signaal, een zogeheten predictie error, dat kan worden gemeten met behulp van EEG. De sterkte van dit signaal wordt verondersteld samen te hangen met de hoeveelheid cognitieve vermogens die aan de onverwachtse verstoring van de voorspelling worden toegewezen. De bevindingen beschreven in dit proefschrift laten zien dat het zelf initiëren van een geluid bij mensen met autisme spectrum stoornis (ASS) niet automatisch resulteert in een afname in elektrische hersenactiviteit. Ook is gevonden dat een plotselinge verstoring in sensorische stimulatie bij mensen met ASS kan resulteren in verhoogde elektrische hersenactiviteit. Deze bevindingen suggereren dat mensen met ASS minder goed in staat lijken te zijn om te anticiperen op sensorische prikkels, en mogelijk meer moeite hebben met de verwerking van onverwachtse verstoringen in sensorische stimulatie. Een verminderd vermogen om te kunnen anticiperen op sensorische prikkels en omgaan met onverwachtse verstoringen in sensorische stimulatie kan niet alleen leiden tot atypische gedragsreacties, waaronder onder- en overgevoeligheid voor sensorische prikkels (symptomen die veel voorkomen bij ASS), maar heeft mogelijk ook gevolgen voor de sociale cognitieve vaardigheden. In sociale situaties is het kunnen anticiperen op hetgeen een ander zegt of doet van cruciaal belang. Het begrijpen van sarcasme vereist bijvoorbeeld de integratie van subtiele verschillen in auditieve (toonhoogte en prosodie) en visuele informatie (gezichtsuitdrukkingen, lichaamstaal). Het juist interpreteren van dergelijke dubbelzinnige sociale signalen is vaak lastig voor mensen met ASS. De bevindingen beschreven in dit proefschrift suggereren dat de oorzaak hiervoor mogelijk ligt in verstoringen in het vermogen om te kunnen anticiperen op sensorische prikkels. Toekomstig onderzoek moet uitwijzen of mensen met ASS ook meer moeite hebben met het anticiperen op sensorische prikkels en verwerken van onverwachtse verstoringen in andere sensorische domeinen. Naast het vergroten van wetenschappelijke kennis over de sensorische informatieverwerking in ASS kan verder onderzoek naar de neurale mechanismen van sensorische anticipatie potentieel leiden tot een elektrofysiologische marker voor ASS die kan worden toegepast als diagnostisch hulpmiddel. Met name voor mensen waarbij de gedragskenmerken niet altijd goed te beoordelen zijn kan een dergelijke biomarker mogelijk als objectief meetinstrument worden ingezet in de klinische praktijk.
- Published
- 2021
326. Spectral indices measurements using miniature fission chambers at the MINERVE zero-power reactor at CEA using calibration data obtained at the BR1 reactor at SCK.CEN
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Wagemans, J. [CEN SCK, Belgian Nucl Res Ctr, B-2400 Mol, (Belgium)]
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- 2012
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327. Monitoring radiation embrittlement during life extension periods.
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Ballesteros, A., Altstadt, E., Gillemot, F., Hein, H., Wagemans, J., Rouden, J., Barthelmes, J., Wilford, K., Serrano, M., Brumovsky, M., Chaouadi, R., and Ortner, S.
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RADIATION , *SURVEILLANCE detection , *EMBRITTLEMENT , *INTEGRALS , *RADIATION monitoring devices - Abstract
Highlights: [•] Techniques and methods for monitoring radiation embrittlement are described. [•] The life extension of the standard surveillance programmes is discussed. [•] Guidance is given for the design of new surveillance capsules. [•] Recommendations for Integrated and Coordinated Surveillance Programmes are given. [ABSTRACT FROM AUTHOR]
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- 2014
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328. Structural Analysis of Jumbo Coliphage phAPEC6
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Jessica Tsonos, Maria Bacia-Verloop, Jeroen Wagemans, Dominique Holtappels, Christine Moriscot, Rob Lavigne, Jean-Paul Noben, Guy Schoehn, Henri De Greve, Jean-Pierre Hernalsteens, Leandro F. Estrozi, Kiandro Fortuna, Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Department of Biology, Vrije Universiteit Brussel (VUB), Institut de biologie structurale (IBS - UMR 5075), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Hasselt University (UHasselt), EM platform ISBG, platforms of the Grenoble Instruct-ERIC centre (ISBG, UMS 3518 CNRS-CEA-UGA-EMBL), Grenoble Partnership for Structural Biology (PSB), ANR-10-INBS-0005,FRISBI,Infrastructure Française pour la Biologie Structurale Intégrée(2010), ANR-17-EURE-0003,CBH-EUR-GS,CBH-EUR-GS(2017), Wagemans, J, Tsonos, J, Holtappels, D, Fortuna, K, Hernalsteens, JP, De Greve, H, Estrozi, LF, Bacia-Verloop, M, Moriscot, C, NOBEN, Jean-Paul, Schoehn, G, Lavigne, R, Biology, Faculty of Sciences and Bioengineering Sciences, Viral Genetics, Structural Biology Brussels, and Department of Bio-engineering Sciences
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0301 basic medicine ,Cryo-electron microscopy ,viruses ,030106 microbiology ,medicine.disease_cause ,Coliphages ,Catalysis ,Virus ,Article ,Inorganic Chemistry ,lcsh:Chemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Viral Proteins ,Genome Size ,Tandem Mass Spectrometry ,jumbo phage ,Microscopy ,medicine ,Physical and Theoretical Chemistry ,Molecular Biology ,Gene ,Escherichia coli ,lcsh:QH301-705.5 ,Spectroscopy ,[SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM] ,Molecular Structure ,Organic Chemistry ,Cryoelectron Microscopy ,Virion ,Viral Genome Packaging ,General Medicine ,3. Good health ,Computer Science Applications ,030104 developmental biology ,chemistry ,Capsid ,lcsh:Biology (General) ,lcsh:QD1-999 ,Transmission electron microscopy ,HK97-fold ,Biophysics ,cryo-EM ,DNA - Abstract
The phAPEC6 genome encodes 551 predicted gene products, with the vast majority (83%) of unknown function. Of these, 62 have been identified as virion-associated proteins by mass spectrometry (ESI-MS/MS), including the major capsid protein (Gp225, present in 1620 copies), which shows a HK97 capsid protein-based fold. Cryo-electron microscopy experiments showed that the 350-kbp DNA molecule of Escherichia coli virus phAPEC6 is packaged in at least 15 concentric layers in the phage capsid. A capsid inner body rod is also present, measuring about 91 nm by 18 nm and oriented along the portal axis. In the phAPEC6 contractile tail, 25 hexameric stacked rings can be distinguished, built of the identified tail sheath protein (Gp277). Cryo-EM reconstruction reveals the base of the unique hairy fibers observed during an initial transmission electron microscopy (TEM) analysis. These very unusual filaments are ordered at three annular positions along the contractile sheath, as well as around the capsid, and may be involved in host interaction.
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- 2020
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329. The BOLD correlates of the visual P1 and N1 in single-trial analysis of simultaneous EEG-fMRI recordings during a spatial detection task
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Novitskiy, N., Ramautar, J.R., Vanderperren, K., De Vos, M., Mennes, M., Mijovic, B., Vanrumste, B., Stiers, P., Van den Bergh, B., Lagae, L., Sunaert, S., Van Huffel, S., and Wagemans, J.
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PERIPHERAL vision , *MAGNETIC resonance imaging , *ELECTRODES , *VISUAL cortex , *INFORMATION processing , *COGNITION - Abstract
Abstract: Simultaneous EEG-fMRI measurements can combine the high spatial resolution of fMRI with the high temporal resolution of EEG. Therefore, we applied this approach to the study of peripheral vision. More specifically, we presented visual field quadrant fragments of checkerboards and a full central checkerboard in a simple detection task. A technique called “integration-by-prediction” was used to integrate EEG and fMRI data. In particular, we used vectors of single-trial ERP amplitude differences between left and right occipital electrodes as regressors in an ERP-informed fMRI analysis. The amplitude differences for the regressors were measured at the latencies of the visual P1 and N1 components. Our results indicated that the traditional event-related fMRI analysis revealed mostly activations in the vicinity of the primary visual cortex and in the ventral visual stream, while both P1 and N1 regressors revealed activation of areas in the temporo-parietal junction. We conclude that simultaneous EEG-fMRI in a spatial detection task can separate visual processing at 100–200ms from stimulus onset from the rest of the information processing in the brain. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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330. Open issues in reactor dosimetry
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Ballesteros, A., Debarberis, L., Voorbraak, W., Wagemans, J., and D’hondt, P.
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RADIATION dosimetry , *NUCLEAR reactors , *NUCLEAR energy , *FIELD emission , *RENEWABLE energy sources , *DECOMMISSIONING of nuclear power plants , *CONFERENCES & conventions , *NEUTRON transport theory - Abstract
Abstract: The need for more energy in a worldwide scope, as well as the necessity to reduce emission, diversification of energy sources and to preserve the environment equilibrium has renewed the expectations of nuclear energy. Programmes for construction of 3rd and 4th generation reactors, modernization of existing nuclear power plants (NPP), and plant life extension are being developed worldwide. Reactor dosimetry plays an important role within all these activities. Most important, it is an essential safety parameter for the assessment of the degradation during operation of structural materials undergoing irradiation in both research and power reactors. This paper reviews and summarizes the open issues that today’s experts consider as the key ones in the reactor dosimetry field. The present paper is based on workshop discussions held in Akersloot, in May 2008, as part of the 13th international symposium on reactor dosimetry. The discussions were focused on the following topics: Reactor surveillance, nuclear data for dosimetry cross-sections, retrospective dosimetry and decommissioning data, neutron and gamma-ray transport calculations, need for benchmarks, radiation damage correlations, and reactor dosimetry for next generation reactors, fusion and high-energy neutron sources. One particular common aspect deserves to be mentioned here. The harmonization among the countries operating NPPs in terms of calculation approaches, measurement techniques, and adjustment procedures should be of high priority. Only then, the NPP end-of-life prediction and its reliability can be substantially improved. This activity has to be based on the exchange of experiences, inter-comparisons, joint experiments, and calculations. [Copyright &y& Elsevier]
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- 2010
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331. Investigation of the (n,p) and (n,α) reactions on 26Al and 36Cl and their astrophysical relevance
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De Smet, L., Wagemans, C., Goeminne, G., Wagemans, J., Heyse, J., and Van Gils, J.
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NUCLEAR reactions , *NUCLEAR astrophysics , *PARTICLES (Nuclear physics) , *CHEMICAL kinetics - Abstract
This paper reports on the results of measurements of the (n,p) and (n,α) reactions on 26Al and 36Cl, in the neutron energy region up to 140 keV and 350 keV, respectively. The experiments were carried out at the GELINA neutron facility of the IRMM (Geel, Belgium). For both reactions several resonances could be identified which were never observed before. Using the obtained cross section data, reaction rates were calculated and compared with other experimental and theoretical values. [Copyright &y& Elsevier]
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- 2005
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332. High resolution measurement of the 36Cl(<f>n,p</f>)36S and 36Cl(<f>n,α</f>)33P reactions
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Wagemans, C., Goeminne, G., De Smet, L., and Wagemans, J.
- Published
- 2003
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333. Realization of nuclear targets by ion implantation: the 17O case.
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Gaelens, M., Loiselet, M., Wagemans, C., Wagemans, J., and Goeminne, G.
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ION implantation , *ION sources - Abstract
At the Centre de Recherches du Cyclotron at Louvain-la-Neuve, we have used the ion implantation technique to provide both radioactive and stable nuclear targets using an ECR ion source. This paper will describe the realization of 17O samples produced for the measurement of the 17O(n,α)14C reaction. The motivation for investigating this reaction and the specific needs for the target are given in another article of this conference (Nikos Prantzos, Sotiris Harinopulos (Eds.), Proceedings of the International Symposium on Nuclear Astrophysics “Nuclei in the Cosmos”, Volos, Greece, 6–11 July, 1998, Editions Frontière, Dreux, p. 33). Here, we will limit ourselves to the technical aspects of the sample production. [Copyright &y& Elsevier]
- Published
- 2002
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334. Comments on Observations on some cases of phenomenal transparency obtained with line drawings
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Zavagno, D, Bianchi, I, Davies, R, Gepstein, S, Ferraris, M, Kelly, R, Smith, B, Orilia, F, Paolini Paoletti, M, Casati, R, Mulligan, K, Savardi, U, Kubovy, M, Bertamini, M, Burigana, L, Zecchinelli, L, Zavagno, D, Agostini, T, Galmonte, A, Verstegen, I, Fossaluzza, C M, Costall, A, and Wagemans, J
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transparency, line drawings, Paolo Bozzi, color ,M-PSI/01 - PSICOLOGIA GENERALE - Abstract
In his 1975 paper, Bozzi presented a sample of transparency effects obtained with achromatic line drawings, that is with drawings made only of black lines and dots. Commenting his work, I will follow the structure of his paper. Without the time to run appropriate experi - ments, and having shown the demos proposed in this work only to a few expert observers, whose descriptions are however consistent with my own impressions, when describing the effects I will rely on what I see, aware of the need for proper experiments to be carried out.
- Published
- 2019
335. The relation between visual orienting functions, daily visual behaviour and visuoperceptual performance in children with (suspected) cerebral visual impairment.
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Ben Itzhak, N., Kooiker, M.J.G., van der Steen, J., Pel, J.J.M., Wagemans, J., and Ortibus, E.
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- *
VISION disorders , *PERFORMANCE in children , *VISUAL perception , *SPACE perception , *EYE tracking - Abstract
Background: Children with cerebral visual impairment (CVI) present heterogeneous visual orienting functions (VOF) and higher-order perception. Multiple assessment methods evaluate CVI, but the relations between them remain unclear.Aim: To investigate the relations between VOF and (1) daily life behaviour and (2) visuoperceptual tests in children with (suspected) CVI.Methods and Procedures: VOF were tested with a validated eye tracking-based paradigm. Visual perception was assessed using the children's visual impairment test for 3- to 6-year olds (CVIT 3-6) and (retrospective) visuoperceptual dimension results. Caregivers completed the Flemish cerebral visual impairment questionnaire (FCVIQ) and an expert panel scored relations between VOF and the other methods. We compared experts' survey responses with data-based results (linear mixed models and correlations).Outcomes and Results: Fourty-four children (23 boys, 21 girls; median age = 7y11mo, SD = 2y7mo) participated. Twenty-one experts completed the survey. Slower VOF was significantly associated with (1) object and face processing impairments, (2) visual (dis)interest, (3) worse visual spatial perception (to local motion and form stimuli), and (4) worse CVIT 3-6 object and scene recognition (to cartoon stimuli).Conclusions and Implications: Integration of VOF with existing visual assessments provides a better clinical picture of CVI and can prevent misdiagnosing children as inattentive, incapable, or unmotivated. [ABSTRACT FROM AUTHOR]- Published
- 2021
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336. Integral experiments in the VENUS-F reactor.
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Kochetkov, A., Aït Abderrahim, H., Baeten, P., Krása, A., Messaoudi, N., Vittiglio, G., and Wagemans, J.
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INTEGRALS , *NUCLEAR power plants , *FLUORITE , *EMPLOYEE training facilities , *DESIGN education , *EXPERIMENTS - Abstract
• Massimo Salvatores was the key persons in the promotion of integral experiments. • He initiated many international programs of integral experiments in the world. • He expressed a great interest to the integral experiments in the VENUS-F facility. • VENUS-F experiments to support ADS MYRRHA and LFR core designs are presented. In spite of the remarkable progress of computational tools in the last decades, integral experiments in zero-power facilities are still of a great importance in the world for nuclear data validation, licensing of new core designs and education and training. Massimo Salvatores was one of the key persons in the promotion of integral experiments and their analysis since the early 1980s. He initiated many international programs of integral experiments in different zero-power facilities in the world. He expressed a great interest to the integral experiments in the VENUS-F facility that have been performed since 2011 to support ADS MYRRHA and LFR core designs. Some of these experiments and associated calculations are presented in this paper. [ABSTRACT FROM AUTHOR]
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- 2021
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337. Eidolons: Novel stimuli for vision research
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Jan, Koenderink, Matteo, Valsecchi, Andrea, van Doorn, Johan, Wagemans, Karl, Gegenfurtner, Koenderink J., Valsecchi M., Doorn A.V., Wagemans J., and Gegenfurtner K.
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Biomedical Research ,Appearance ,Awarene ,Awareness ,Amblyopia ,Contrast Sensitivity ,Form Perception ,Local sign ,Sensory Thresholds ,Natural image ,Humans ,Algorithms ,Human ,Sensory Threshold - Abstract
Meanings and qualities are fundamental attributes of visual awareness. We propose ''eidolons'' as a tool for establishing equivalence classes of appearance along meaningful dimensions. The ''eidolon factory'' is an algorithm that generates stimuli in such a meaningful and transparent way. The algorithm allows us to focus on location, scale, and size of perceptually salient structures, proto-objects, and perhaps even semantics rather than global overall parameters, such as contrast and spatial frequency. The eidolon factory is based on models of the psychogenesis of visual awareness. It affects the image in terms of the disruption of image structure across space and spatial scales. This is a very general method with many potential applications. We illustrate a few instances. We present results for the example of tarachopic amblyopia, showing that scrambled vision is indeed an apt interpretation.
- Published
- 2017
338. Mutual interplay between perceptual organization and attention: a neuropsychological perspective
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Gillebert, C, Humphreys, G, and Wagemans, J
- Abstract
An efficient representation of the environment requires both the selection of a fraction of the information that reaches our senses and the organization of this information into coherent and meaningful elements. Here we discuss the dynamic interplay between selective attention and perceptual organization, important processes that allow us to perceive a seamless, integrated world. Based on evidence from behavioral and neuroimaging studies with normal observers and neuropsychological patients, we examine whether: (i) perceptual grouping constrains visual attention, determining which objects will be selected and be candidates for explicit report; (ii) visual attention modulates perceptual grouping, determining how elements are grouped to form meaningful wholes. The data suggest that, whilst not being necessary for at least some forms of perceptual grouping, visual attention can nevertheless modulate grouping. We conclude that selection is dynamically set by bottom-up stimulus factors, top-down knowledge and the allocation of attention to space and within grouped regions of objects.
- Published
- 2016
339. Tactile and haptic perceptual organization
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Kappers, A.M.L., Bergmann Tiest, W.M., and Wagemans, J.
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- 2015
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340. Mechanisms for neutron and light charged-particle emission during nuclear fission
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CARJAN, N., Mas, Virginie, C. Wagemans, J. Wagemans, P. D'Hondt, C. Wagemans, J. Wagemans, and P. D'Hondt
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[PHYS.NUCL] Physics [physics]/Nuclear Theory [nucl-th] ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,ComputingMilieux_MISCELLANEOUS - Published
- 2010
341. Systematics on even-odd effects in fission fragments yields: comparison between symmetric and asymmetric splits
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F. Rejmund, M. Caamano, Lion, Michel, C. Wagemans, J. Wagemans, P. D'hondt, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), C. Wagemans, J. Wagemans, and P. D'hondt
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Nuclear physics ,Systematics ,Fission ,[PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex] ,Nuclear Theory ,Physics::Atomic and Molecular Clusters ,Zoology ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,Biology ,Nuclear Experiment - Abstract
International audience; Even-odd effects in fission fragment yields is investigated for symmetric and asymmetric splits of different fissioning systems. Data in inverse kinematics obtained at GSI gave for the first time the complete elemental yields over a broad range of fissioning systems. These data indicate that the even-odd effetct at symmetry is independent of the fissibility of the fissioning sytem. New data in inverse kinematics are required to conclude on this topic that impacts strongly our understanding on fission dynamics.
- Published
- 2008
342. Altered category learning and reduced generalization in autistic adults.
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Van Overwalle J, Van der Donck S, Geusens B, Boets B, and Wagemans J
- Abstract
Individuals with autism spectrum condition (ASC) are suggested to experience difficulties with categorization and generalization. However, empirical studies have mainly focused on one process at a time, and neglected underlying neural mechanisms. Here, we investigated categorization and generalization at a behavioral and neural level in 38 autistic and 38 neurotypical (NT) adults. By presenting shapes sampled from an artificial multidimensional stimulus space, we investigated (1) behavioral and neural underpinnings of category learning and (2) behavioral generalization of trained categorization to both an extended version of the stimulus space and a novel stimulus space. Our previous findings showed that individuals with autism were slower in category learning. In this study, we demonstrate that this slower learning in autism was not related to differences in applied categorization strategy. In contrast, electroencephalography recordings during training did reveal a reduced amplitude of the N1 component in the right occipital temporal cortex after stimulus presentation in autistic participants, which suggests atypical categorical proficiency. In addition, we observed delayed and higher activation in the frontal regions after receiving (negative) feedback in the autistic group, potentially suggesting more explicit feedback processing or a higher salience of prediction errors in autism. Finally, autistic and NT individuals were able to generalize their learned categorization after training. However, when generalizing to a novel set of shapes, autistic individuals were significantly less accurate. Reduced generalization significantly correlated with increased intolerance to uncertainty scores. This multi-level approach reveals behavioral and neural differences in learning and generalization that could be related to clinical symptoms in autism., (© 2024 International Society for Autism Research and Wiley Periodicals LLC.)
- Published
- 2024
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343. Isolation, characterization and genome analysis of the orphan phage Kintu infecting Xanthomonas vasicola pv. musacearum.
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Nakayinga R, Ntulume I, Wagemans J, Vallino M, Kanaabi R, Kajubi A, and Kwetegyeka J
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- Sewage virology, Sewage microbiology, Microscopy, Electron, Transmission, Phylogeny, DNA, Viral genetics, Genome, Viral, Xanthomonas virology, Xanthomonas genetics, Musa microbiology, Musa virology, Plant Diseases microbiology, Bacteriophages genetics, Bacteriophages isolation & purification, Bacteriophages classification, Bacteriophages physiology, Siphoviridae genetics, Siphoviridae isolation & purification, Siphoviridae classification, Siphoviridae physiology
- Abstract
Background: Xanthomonas vasicola pv. musacearum is responsible for the widespread Banana Xanthomonas Wilt in banana cultivation regions across the globe. Biocontrol measures for disease management remain limited amidst increasing antimicrobial resistance and unsustainable conventional agricultural practices. The purpose of this study is to explore a viable alternative or adjunct strategy through the use of bacteriophages for disease management., Results: Kintu was isolated from sewage and displayed clear and circular plaques measuring 3 mm. Based on transmission electron microscopy, Kintu displays siphovirus characteristics, including an icosahedral head and a non-contractile tail. Kintu infects 78% (22 out of 28) Ugandan Xvm strains, has an optimal multiplicity of infection of 1, a 10 min adsorption and latent period, a 35 min burst period, and a burst size of 15 particles per bacterium. Phage titers remain stable for two and half months (75 days) in SM buffer at -20
o C and - 40o C but decrease significantly (p ≤ 0.0001) at 4o C. Kintu is active at pH 3 and 11, maintains viability at temperatures between 25o C and 120o C and tolerates UV irradiation for up to 2 min and 20 s. Kintu inhibits Xvm growth at MOI ratios of 0.1, 1 and 10. The genome is a double stranded DNA molecule that consists of 48,985 base pairs and a G + C content of 51.71%. Antibiotic resistance genes or genes associated with a lysogenic life cycle are absent. There is limited sequence similarity of Kintu with other phages, making it a novel phage belonging to an unclassified genus of the class Caudoviricetes., Conclusion: Kintu is a novel bacteriophage that infects and lyses Xanthomonas vasicola pv. musacearum, the causative agent for Banana Xanthomonas Wilt. Its stability across diverse temperatures and pH conditions highlights its potential as a biocontrol agent for managing the disease., Competing Interests: Declarations Ethics approval and consent to participate Not applicable. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)- Published
- 2024
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344. Antibiotic profile classification of Proteus mirabilis using machine learning: An investigation into multidimensional radiomics features.
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Khorasani A, Moghim S, Wagemans J, Lavigne R, and Mirzaei A
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- Humans, Proteus Infections diagnostic imaging, Proteus Infections microbiology, Urinary Tract Infections diagnostic imaging, Urinary Tract Infections microbiology, Radiomics, Proteus mirabilis drug effects, Machine Learning, Anti-Bacterial Agents pharmacology
- Abstract
Antimicrobial resistance (AMR) presents a significant threat to global healthcare. Proteus mirabilis causes catheter-associated urinary tract infections (CAUTIs) and exhibits increased antibiotic resistance. Traditional diagnostics still rely on culture-based approaches, which remain time-consuming. Here, we study the use of machine learning (ML) to classify bacterial resistance profiles using straightforward microscopic imaging of P. mirabilis for resistance classification integrated with radiomics feature analysis and ML models. From 150 P. mirabilis strains isolated from catheters of patients diagnosed with a CAUTI, 30 % displayed multidrug resistance using the standardized disk diffusion method, and 60 % showed strong biofilm activity in microtiter plate assays. As a more rapid alternative, we introduce wavelet-based and regular microscopy imaging with feature extraction/selection, following image preprocessing steps (image denoising, normalization, and mask creation). These features enable training and testing different ML models with 5-fold cross-validation for P. mirabilis resistance classification. From these models, the Random Forest (RF) algorithm exhibited the highest performance with ACC = 0.95, specificity = 0.97, sensitivity = 0.88, and AUC = 0.98 among the other ML algorithms considered in this study for P. mirabilis resistance classification. This successful application of wavelet-based feature Radiomics analysis with RF model represents a crucial step towards a precise, rapid, and cost-effective method to distinguish antibiotic resistant P. mirabilis strains., Competing Interests: Declaration of competing interest The authors of this manuscript have no conflicts of interest to declare, and all the listed authors have actively contributed to the research and preparation of this manuscript. We have included the names and affiliations of all authors in the manuscript file., (Copyright © 2024 Elsevier Ltd. All rights reserved.)
- Published
- 2024
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345. Characterization of four Acidovorax phages and their potential in phage biocontrol for lamb's lettuce seed decontamination.
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Holtappels D, Vieira FG, Voet M, Vallino M, Van Vaerenbergh J, Lavigne R, and Wagemans J
- Abstract
Bacterial black spot, caused by Acidovorax valerianellae , is responsible for significant yield losses in lamb's lettuce ( Valerianella locusta ) in many producing countries, especially Europe. Currently, no resistant varieties of V. locusta are available that effectively control the disease under field conditions. Bacteriophage-based biocontrol has been suggested as a sustainable and natural alternative strategy to combat bacterial pathogens. In this study, novel phages infecting A. valerianellae and Acidovorax cattleyae , Alfacinha1, Alfacinha3, Acica, and Aval, were isolated and characterized. Based on comparative genomics, these phages represent three new phage genera. Aval and Acica phages revealed genomic features characteristic of temperate lifestyle, encoding toxins likely associated with lysogenic conversion, which contrasts with Alfacinha1 and Alfacinha3. The latter was selected for application as a biocontrol agent during seed steeping. This phage reaches an 87% reduction in the A. valerianellae concentration on artificially infested seeds. Importantly, this reduction results in an increased germination rate from 58.9% to 93.3%. Moreover, the infected seedlings had a dramatic reduction in vigor index after 22 days of growth, whereas the phage-treated ones had a vigor index similar to the negative control, reinforcing the ability of bacteriophages to effectively reduce disease progression. We further evaluated the impact of lipopolysaccharides in phage suspensions on the development of seedlings. Here, we demonstrated that the presence of lipopolysaccharides do have an impact on seedling development, significantly reducing the number of roots developed. This study shows how genomic analyses and tailored bioassays represent an essential route to ensure safe phage application and demonstrates the potential of a phage-based biocontrol strategy against A. valerianellae .IMPORTANCEBacteria continue to globally cause serious damage to a variety of crops. One example is a bacterial black spot of lamb's lettuce caused by Acidovorax valerianellae . It has spread across Europe, resulting in economic losses of at least 10% in tonnage annually. Faced with the inefficiency of conventional control methods, an alternative and sustainable strategy based on the use of bacteriophages was pursued in this study. We present for the first time the isolation and characterization of A. valerianellae -specific phages. Moreover, we assessed their biocontrol potential in seed decontamination since the disease primarily spreads from seeds to seedlings. Interestingly, seed treatment with one of our phages reaches an 87% reduction in bacterial concentration. More importantly, this reduction results in an increased germination rate from 58.9% to 93.3%. Finally, our study demonstrated for the first time the need for removing endotoxins from phage suspensions as they impact plant development when used as a biocontrol agent.
- Published
- 2024
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346. Isolation and Antibiofilm Activity of Bacteriophages against Cutibacterium acnes from Patients with Periprosthetic Joint Infection.
- Author
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Chen B, Chittò M, Tao S, Wagemans J, Lavigne R, Richards RG, Metsemakers WJ, and Moriarty TF
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- Humans, Phage Therapy methods, Gram-Positive Bacterial Infections therapy, Gram-Positive Bacterial Infections microbiology, Host Specificity, Propionibacteriaceae physiology, Bacterial Load, Biofilms drug effects, Bacteriophages physiology, Bacteriophages isolation & purification, Prosthesis-Related Infections microbiology, Prosthesis-Related Infections therapy
- Abstract
Background: Infections following shoulder surgery, particularly periprosthetic joint infection (PJI), are challenging to treat. Cutibacterium acnes is the causative pathogen in 39% to 76% of these cases. This study explores the efficacy of bacteriophage therapy as an alternative to conventional antibiotics for treating such infections., Methods: Nine phages with lytic activity were isolated from the skin of humans using C. acnes ATCC 6919 as the indicator host. These phages were tested individually or in combination to assess host range and antibiofilm activity against clinical strains of C. acnes associated with PJIs. The phage cocktail was optimized for broad-spectrum activity and tested in vitro against biofilms formed on titanium discs to mimic the prosthetic environment., Results: The isolated phages displayed lytic activity against a range of C. acnes clinical isolates. The phage cocktail significantly reduced the bacterial load of C. acnes strains 183, 184, and GG2A, as compared with untreated controls ( p < 0.05). Individual phages, particularly CaJIE7 and CaJIE3, also demonstrated significant reductions in bacterial load with respect to specific strains. Moreover, phages notably disrupted the biofilm structure and reduced biofilm biomass, confirming the potential of phage therapy in targeting biofilm-associated infections., Conclusions: Our preclinical findings support the potential of phage therapy as a viable adjunct to traditional antibiotics for treating C. acnes infections in orthopedic device-related infections. The ability of phages to disrupt biofilms may be particularly beneficial for managing infections associated with prosthetic implants.
- Published
- 2024
- Full Text
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347. Targeting Pseudomonas aeruginosa biofilm with an evolutionary trained bacteriophage cocktail exploiting phage resistance trade-offs.
- Author
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Kunisch F, Campobasso C, Wagemans J, Yildirim S, Chan BK, Schaudinn C, Lavigne R, Turner PE, Raschke MJ, Trampuz A, and Gonzalez Moreno M
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- Pseudomonas Phages physiology, Pseudomonas Phages genetics, Humans, Phage Therapy methods, Drug Resistance, Multiple, Bacterial, Pseudomonas Infections therapy, Pseudomonas Infections microbiology, Host Specificity, Microbial Sensitivity Tests, Pseudomonas aeruginosa virology, Pseudomonas aeruginosa physiology, Pseudomonas aeruginosa drug effects, Biofilms growth & development, Bacteriophages physiology, Bacteriophages genetics, Anti-Bacterial Agents pharmacology
- Abstract
Spread of multidrug-resistant Pseudomonas aeruginosa strains threatens to render currently available antibiotics obsolete, with limited prospects for the development of new antibiotics. Lytic bacteriophages, the viruses of bacteria, represent a path to combat this threat. In vitro-directed evolution is traditionally applied to expand the bacteriophage host range or increase bacterial suppression in planktonic cultures. However, while up to 80% of human microbial infections are biofilm-associated, research towards targeted improvement of bacteriophages' ability to combat biofilms remains scarce. This study aims at an in vitro biofilm evolution assay to improve multiple bacteriophage parameters in parallel and the optimisation of bacteriophage cocktail design by exploiting a bacterial bacteriophage resistance trade-off. The evolved bacteriophages show an expanded host spectrum, improved antimicrobial efficacy and enhanced antibiofilm performance, as assessed by isothermal microcalorimetry and quantitative polymerase chain reaction, respectively. Our two-phage cocktail reveals further improved antimicrobial efficacy without incurring dual-bacteriophage-resistance in treated bacteria. We anticipate this assay will allow a better understanding of phenotypic-genomic relationships in bacteriophages and enable the training of bacteriophages against other desired pathogens. This, in turn, will strengthen bacteriophage therapy as a treatment adjunct to improve clinical outcomes of multidrug-resistant bacterial infections., (© 2024. The Author(s).)
- Published
- 2024
- Full Text
- View/download PDF
348. Optimization of bacteriophage therapy for difficult-to-treat musculoskeletal infections: a bench-to-bedside perspective.
- Author
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Bessems L, Chen B, Uyttebroek S, Devolder D, Lood C, Verwimp S, De Munter P, Debaveye Y, Depypere M, Spriet I, Van Gerven L, Dupont L, Wagemans J, van Noort V, Lavigne R, Metsemakers WJ, and Onsea J
- Subjects
- Humans, Prospective Studies, Bacterial Infections therapy, Musculoskeletal Diseases therapy, Musculoskeletal Diseases microbiology, Bacteria virology, Phage Therapy methods, Bacteriophages physiology
- Abstract
Given the increasing threat of antimicrobial resistance, scientists are urgently seeking adjunct antimicrobial strategies, such as phage therapy (PT). However, despite promising results for the treatment of musculoskeletal infections in our center, crucial knowledge gaps remain. Therefore, a prospective observational study (PHAGEFORCE) and a multidisciplinary approach was set up to achieve and optimize standardized treatment guidelines. At our center, PT is strictly controlled and monitored by a multidisciplinary taskforce. Each phage treatment follows the same pathway to ensure standardization and data quality. Within the PHAGEFORCE framework, we established a testing platform to gain insight in the safety and efficacy of PT, biodistribution, phage kinetics and the molecular interaction between phages and bacteria. The draining fluid is collected to determine the phage titer and bacterial load. In addition, all bacterial isolates are fully characterized by genome sequencing to monitor the emergence of phage resistance. We hereby present a standardized bench-to-bedside protocol to gain more insight in the kinetics and dynamics of PT for musculoskeletal infections., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Bessems, Chen, Uyttebroek, Devolder, Lood, Verwimp, De Munter, Debaveye, Depypere, Spriet, Van Gerven, Dupont, Wagemans, van Noort, Lavigne, Metsemakers and Onsea.)
- Published
- 2024
- Full Text
- View/download PDF
349. Varieties of pictorial vision.
- Author
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Koenderink J, van Doorn A, and Wagemans J
- Abstract
Pictorial awareness is addressed through experimental phenomenology involving over 90 naïve participants. Since one can't look at the "same" picture twice the study uses one-shot trials. The participant's fascination for the duration of a session is held through the artistic principle of theme and variation. Six variations focus on the theme of pictorial geometry, both two-dimensional and three-dimensional. Major findings are: Idiosyncratic deviations from veridical are huge as compared to common textbook "effects." Observers wield arbitrary heuristics for tasks that are "formally related." The assumption of a common formal framework is apparently unsound. The notion of "inverse optics" is misleading. A fair fraction of the population appears to lack monocular stereopsis as intuitive awareness. It suggests an as-yet unrecognized, but perhaps common variety of aphantasia., Competing Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2024.)
- Published
- 2024
- Full Text
- View/download PDF
350. Evaluation of antibiofilm agents for treatment of cystic fibrosis-related chronic rhinosinusitis.
- Author
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Uyttebroek S, Dupont L, Wagemans J, Lavigne R, Merabishvili M, Coenye T, and Van Gerven L
- Abstract
Key Points: Treatment of cystic fibrosis-related chronic rhinosinusitis should target sinonasal biofilms. NaHCO
3 salts with/without xylitol have limited antibiofilm properties, whereas rhDNAse has not. Phage effectivity varies and depends on the phage and the combination with antibiotics., (© 2024 The Author(s). International Forum of Allergy & Rhinology published by Wiley Periodicals LLC on behalf of American Academy of Otolaryngic Allergy and American Rhinologic Society.)- Published
- 2024
- Full Text
- View/download PDF
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