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Peer Reviewed
See detailIodide organification disorder in autonomous thyroid nodule.
Tang, B. N. T.; Corvilain, B.; Seret, Alain ULg et al

Poster (2005, November 15)

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Peer Reviewed
See detailIodide organification disorder in autonomous thyroid nodule.
Tang, B.; Corvilain, B.; Seret, Alain ULg et al

in European Journal of Nuclear Medicine and Molecular Imaging (2006), 33(S2), 351

Detailed reference viewed: 32 (1 ULg)
See detailIon abundance rations of the Jovian magnetosphere
Radioti, Aikaterini ULg; Krupp, N.; Woch, J. et al

Conference (2004)

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See detailIon abundance ratios in the Jovian magnetosphere
Radioti, Aikaterini ULg; Krupp, N.; Woch, J. et al

in Journal of Geophysical Research. Space Physics (2005), 110

Galileo, as the first orbiting spacecraft around Jupiter, provides the opportunity to study globally the composition of the energetic ion population in the equatorial plane of the Jovian magnetosphere ... [more ▼]

Galileo, as the first orbiting spacecraft around Jupiter, provides the opportunity to study globally the composition of the energetic ion population in the equatorial plane of the Jovian magnetosphere. This enables us to derive the relative importance of the various sources and sinks of plasma and energetic particles in the largest magnetosphere of our solar system. In this paper we use data from the Energetic Particles Detector (EPD) on board Galileo and derive relative ion abundance ratio maps of S/O, S/He, O/He, and p/He. We extend the previous work in terms of global coverage, species, and energy range. In addition we compare them with previous results and especially with those derived on board Voyager 2. We found that the S/O abundance ratio is relatively constant throughout the magnetosphere decreasing slightly with radial distance. Within the error bars the S/O ratios could be reproduced. Only a minor energy dependence is observed for this ratio pointing to a common source for both ions. The S/He-, O/He-, and p/He-ratios decrease with increasing radial distance, furthering the notion that sulfur, oxygen, and protons originate mainly from a source within the Jovian system, in contrast with helium, which originates from the solar wind. A spectral kink observed at energies of several 100 keV/ nuc for all species and most pronounced for helium explains the observed energy dependence of the ratios relative to helium. Differences in the abundance ratios up to more than one order of magnitude between sequential orbits are evidence of large temporal variations taking place in the Jovian magnetosphere. These variations and the strong energy dependence can explain the differences between the results derived from Galileo EPD measurements and those from Voyager data. [less ▲]

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See detailIon beam figuring for precision optics
Gailly, Patrick ULg

E-print/Working paper (2008)

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See detailION BEAM FIGURING OF CVD SILICON CARBIDE MIRRORS
Gailly, Patrick ULg

in Warmbein, B (Ed.) Proceedings of the 5th International Conference on Space Optics (ICSO 2004) (2004, March)

Optical and structural elements made of silicon carbide are increasingly found in space instruments. Chemical vapor deposited silicon carbide (CVD-SiC) is used as a reflective coating on SiC optics in ... [more ▼]

Optical and structural elements made of silicon carbide are increasingly found in space instruments. Chemical vapor deposited silicon carbide (CVD-SiC) is used as a reflective coating on SiC optics in reason of its good behavior under polishing. The advantage of applying ion beam figuring (IBF) to CVD-SiC over other surface figure-improving techniques is discussed herein. The results of an IBF sequence performed at the Centre Spatial de Liège on a 100 mm CVD-SiC mirror are reported. The process allowed to reduce the mirror surface errors from 243 nm to 13 nm rms . Beside the surface figure, roughness is another critical feature to consider in order to preserve the optical quality of CVD-SiC . Thus, experiments focusing on the evolution of roughness were performed in various ion beam etching conditions. The roughness of samples etched at different depths down to 3 m was determined with an optical profilometer. These measurements emphasize the importance of selecting the right combination of gas and beam energy to keep roughness at a low level. Kaufman-type ion sources are generally used to perform IBF but the performance of an end-Hall ion source in figuring CVD-SiC mirrors was also evaluated in this study. In order to do so, ion beam etching profiles obtained with the end-Hall source on CVD-SiC were measured and used as a basis for IBF simulations. [less ▲]

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See detailIon beam figuring of precision aspheric optical surfaces
Gailly, Patrick ULg; Collette, Jean-Paul; Tock, Jean-Philippe et al

Conference (1999)

An ion beam figuring facility is fully operational at the Centre Spatial de Liège since 1997. Ion beam figuring principle is briefly reminded and the present capabilities of the technique are described ... [more ▼]

An ion beam figuring facility is fully operational at the Centre Spatial de Liège since 1997. Ion beam figuring principle is briefly reminded and the present capabilities of the technique are described. An extensive characterisation programme is running in order to determine the optimised parameters for numerous materials and operating conditions. In this frame, tests have been performed on various optics to demonstrate the capability of the technique to figure aspheric shapes on glass or metallic substrates. At first, an aspherisation on a spherical gold-coated aluminium mirror plated in between with Nickel is presented. After removal of the gold coating with the ion beam, micro-roughness and etching rate measurements have been performed on the substrate material. Finally, the mirror has been figured from the original sphere to a parabola. The surface characteristics evolution is described in terms of micro-roughness and surface error. Other examples of complex aspherical figuring (polynomials of high order, ...) are shown. In conclusion, the potential impact and the results of this technique on optics fabrication, especially for exotic shapes, are exposed. The integration of the ion beam figuring process in a classical optics manufacturing sequence will be discussed, identifying the potential time and money savings. [less ▲]

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See detailIon beam figuring of small BK7 and Zerodur optics : thermal effects
Gailly, Patrick ULg; Collette, Jean-Paul; Renson, Luc et al

in Geyl, Roland; Maxwell, Jonathan (Eds.) Optical Fabrication and Testing, Proc. SPIE Volume: 3739 (1999, September 06)

optics these last years. One of the disadvantages of ion figuring is the high surface temperature of the workpiece. Temperature aspects have already been mentioned by some authors but are weakly detailed ... [more ▼]

optics these last years. One of the disadvantages of ion figuring is the high surface temperature of the workpiece. Temperature aspects have already been mentioned by some authors but are weakly detailed. Therefore thermal effects on BK7 and Zerodur, mainly surface figure distortions and surface temperature measurements, have been investigated here in more detail. Distortion of the optical figure due to high temperature and temperature gradients induced by ion figuring is described. High figure distortion has been observed on 10 cm diameter BK7 samples. Distortions can also be observed on Zerodur samples (although much weaker). Differences between BK7 and Zerodur distortions are discussed. In order to analyse the nonuniform heating of the workpiece during ion bombardment, the surface temperature has been monitored with an infrared camera. Furthermore, surface temperature measurements with respect to ion beam parameters have also been performed. All these measurements show the necessity to care about thermal aspects during ion beam figuring for some sensible materials like BK7, but even for low expansion material like Zerodur. [less ▲]

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See detailIon Beam Induced Luminescence & Cultural Heritage
Calvo Del Castillo, Helena ULg

Scientific conference (2007, December)

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See detailIon Beam Induced Luminescence & Cultural Heritage
Calvo Del Castillo, Helena ULg

Scientific conference (2007, April)

Detailed reference viewed: 5 (0 ULg)
Peer Reviewed
See detailIon beam induced luminescence of minerals
Calvo Del Castillo, Helena ULg; Ruvalcaba Sil, Jose Luis; Calderón, Tomás

Poster (2006)

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See detailIon channel modulators: more diversity than previously thought
Dilly, Sébastien ULg; Lamy, Cédric; Marrion, Neil et al

in Chembiochem : A European Journal of Chemical Biology (2011), 12(12), 1808-1812

Ion channel function can be modified in various ways. For example, numerous studies have shown that currents through voltage-gated ion channels are affected by pore block or modification of voltage ... [more ▼]

Ion channel function can be modified in various ways. For example, numerous studies have shown that currents through voltage-gated ion channels are affected by pore block or modification of voltage-dependence of activation/inactivation. Recent experiments performed on various ion channels show that allosteric modulation is an important mechanism to affect channel function. For instance, in KCa2 (formerly SK) channels, the prototypic “blocker” apamin prevents conduction by an allosteric mechanism, while TRPV1 channels are prevented from closing by a tarantula toxin, DkTx, through an interaction with residues located away from the selectivity filter. The recent evidence therefore suggests that, in several ion channels, the region around the outer mouth of the pore is rich in binding sites which may be exploited therapeutically. These discoveries also suggest that the pharmacological vocabulary should be adapted to define these various actions. [less ▲]

Detailed reference viewed: 47 (13 ULg)
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See detailIon Dissociation Kinetics in Mass Spectrometry
Leyh, Bernard ULg

in Reedijk, J. (Ed.) Reference Module in Chemistry, Molecular Sciences and Chemical Engineering (2013)

The variation of fragmentation rate constants as a function of the parent ion internal energy, or, alternatively, as a function of temperature, is crucial information to unravel the dissociation ... [more ▼]

The variation of fragmentation rate constants as a function of the parent ion internal energy, or, alternatively, as a function of temperature, is crucial information to unravel the dissociation mechanisms of molecular ions. This contribution provides the reader first with basic information on the statistical theories used to model unimolecular rate constants. Various experimental methods to measure such rate constants in the 102 to 1010 s^(-1) range are then discussed. Kinetic isotope effects are also briefly dealt with. How reaction mechanisms can be inferred from kinetic data is handled in an extensive section where selected examples from the recent literature are discussed. [less ▲]

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See detailIon homeostasis in the chloroplast
Hanikenne, Marc ULg; Bernal, Maria; Urzica, Eugen

in Wollman, Francis-Andre; Theg, Steve M. (Eds.) Plastid Biology (in press)

The chloroplast is an organelle of high demand for macro- and micro-nutrient ions, which are required for the maintenance of the photosynthetic process. To avoid deficiency while preventing excess ... [more ▼]

The chloroplast is an organelle of high demand for macro- and micro-nutrient ions, which are required for the maintenance of the photosynthetic process. To avoid deficiency while preventing excess, homeostasis mechanisms must be tightly regulated. Here, we describe the needs for nutrient ions in the chloroplast and briefly highlight their functions in the chloroplastidial metabolism. We further discuss the impact of nutrient deficiency on chloroplasts and the acclimation mechanisms that evolved to preserve the photosynthetic apparatus. We finally present what is known about import and export mechanisms for these ions. Whenever possible, a comparison between cyanobacteria, algae and plants is provided to add an evolutionary perspective to the description of ion homeostasis mechanisms in photosynthesis. [less ▲]

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See detailIon Mobility - Mass Spectrometry as a new approach for the screening of pesticide residues in food
Joly, Laure; Goscinny, Séverine ULg; Touilloux, Romain et al

Conference (2011, September)

Detailed reference viewed: 35 (0 ULg)