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See detailGadolinium DOTA Chelates Featuring Alkyne Groups Directly Grafted on the Tetraaza Macrocyclic Ring: Synthesis, Relaxation Properties, "Click" Reaction, and High-Relaxivity Micelles
Vanasschen, Christian; Bouslimani, Nouri ULg; Thonon, David ULg et al

in Inorganic Chemistry (2011), 50(18), 8946-8958

This paper reports on the synthesis and relaxivity properties of tetraacetic DOTA-type chelating agents featuring one or two alkyne groups directly grafted on the tetraaza macrocyclic ring and available ... [more ▼]

This paper reports on the synthesis and relaxivity properties of tetraacetic DOTA-type chelating agents featuring one or two alkyne groups directly grafted on the tetraaza macrocyclic ring and available for "click" reactions with azide-bearing substrates. The racemic DOTAma ligand bearing one alkyne group was obtained by a bisaminal template route. The same approach was used to prep. ligand DOTAda substituted by two alkyne groups located on two adjacent carbon atoms. The S,S enantiomer of DOTAda was also prepd. by a "crab-like" condensation. This ligand is the first example of a DOTA deriv. featuring two reactive functions adjacent to each other on the macrocyclic ring. A triacetic monoalkyne ligand (DO3ma) was also synthesized for comparison purposes. NMR studies indicate that the Yb(III) chelates of DOTAma and DOTAda adopt two conformations in solns. in which the tetraaza ring is rigidified. The hydration state of the Eu(III) chelates was detd. by luminescence spectroscopy, and the water exchange time of the Gd(III) complexes was measured by 17O NMR. Ring substitution accelerates the water exchange. These data were used to interpret nuclear magnetic relaxation dispersion curves of the Gd(III) chelates. Two long aliph. chains have been added to DOTAda by a "click" procedure to form the (C18)2DOTAda ligand. The corresponding Gd(III) complex forms micelles of unusually high relaxivity presumably because of the close proximity of the aliph. chains on the macrocyclic ring that ensures a rigid double anchoring into the micelles. [less ▲]

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See detailA gadolinium triacetic monoamide DOTA derivative with a methanethiosulfonate anchor group. Relaxivity properties and conjugation with albumin and thiolated particles
Thonon, David ULg; Jacques, Vincent; Desreux, Jean-François ULg

in Contrast Media & Molecular Imaging (2007), 2

The gadolinium(III) complex with a new DOTA-based ligand bearing a methanethiosulfonate group (MTS) was synthesized and its relaxivity properties were investigated. MTS-ADO3A is a triacid DOTA derivative ... [more ▼]

The gadolinium(III) complex with a new DOTA-based ligand bearing a methanethiosulfonate group (MTS) was synthesized and its relaxivity properties were investigated. MTS-ADO3A is a triacid DOTA derivative with an amide arm substituted by an ethylmethanethiosulfonate function. This ligand was obtained in two steps: tri-tert-butyl 2,2′,2″-(1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetate was reacted with S-(2-aminoethyl)methanesulfonothioate and the tert-butyl groups were removed with trifluoroacetic acid. The Gd(III) MTS–ADO3A complex readily formed disulfide bonds with albumin (BSA) in its native and reduced forms and with thiolated silica particles. Four- to five-fold relaxivity increases at 20 MHz were measured on the isolated adducts. The EuMTS-ADO3A chelate was found to be monohydrated by fluorescence and the relaxivity parameters of the Gd(III) complex were obtained by 17O NMR and by measuring the nuclear magnetic relaxation dispersion between 0.01 and 80 MHz. The water exchange time τm is increased upon forming disulfide bonds with macromolecules and particles and the relaxivity gains of all the complexes are limited by the τm factor. Forming covalent or hydrophobic/electrostatic bonds with BSA seems to bring about similar relaxivity changes but the covalent BSA adducts can be isolated and their properties can be directly studied. The addition of dithiothreitol or glutathione leads to the removal of the metal chelates from the macromolecules, as indicated by the relaxation times reverting to their values before binding. It is thus expected that the chelate will stay in the body long enough for imaging but will still be excreted through the kidneys. [less ▲]

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See detailGAIA and the spectroscopic binaries: what to expect in terms of orbit determination?
Pourbaix, D.; Jancart, Sylvie ULg

in GAIA Spectroscopy: Science and Technology (2003)

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See detailThe Gaia astrophysical parameters inference system (Apsis). Pre-launch description
Bailer-Jones, C. A. L.; Andrae, R.; Arcay, B. et al

in Astronomy and Astrophysics (2013), 559

The Gaia satellite will survey the entire celestial sphere down to 20th magnitude, obtaining astrometry, photometry, and low resolution spectrophotometry on one billion astronomical sources, plus radial ... [more ▼]

The Gaia satellite will survey the entire celestial sphere down to 20th magnitude, obtaining astrometry, photometry, and low resolution spectrophotometry on one billion astronomical sources, plus radial velocities for over one hundred million stars. Its main objective is to take a census of the stellar content of our Galaxy, with the goal of revealing its formation and evolution. Gaia's unique feature is the measurement of parallaxes and proper motions with hitherto unparalleled accuracy for many objects. As a survey, the physical properties of most of these objects are unknown. Here we describe the data analysis system put together by the Gaia consortium to classify these objects and to infer their astrophysical properties using the satellite's data. This system covers single stars, (unresolved) binary stars, quasars, and galaxies, all covering a wide parameter space. Multiple methods are used for many types of stars, producing multiple results for the end user according to different models and assumptions. Prior to its application to real Gaia data the accuracy of these methods cannot be assessed definitively. But as an example of the current performance, we can attain internal accuracies (RMS residuals) on F,G,K,M dwarfs and giants at G=15 (V=15-17) for a wide range of metallicites and interstellar extinctions of around 100K in effective temperature (Teff), 0.1mag in extinction (A0), 0.2dex in metallicity ([Fe/H]), and 0.25dex in surface gravity (logg). The accuracy is a strong function of the parameters themselves, varying by a factor of more than two up or down over this parameter range. After its launch in November 2013, Gaia will nominally observe for five years, during which the system we describe will continue to evolve in light of experience with the real data. [less ▲]

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See detailThe Gaia satellite: a tool for Emission Line Stars and Hot Stars
Martayan, C.; Frémat, Y.; Blomme, R. et al

in SF2A-2008 (2008, November 01)

The Gaia satellite will be launched at the end of 2011. It will observe at least 1 billion stars, and among them several million emission line stars and hot stars. Gaia will provide parallaxes for each ... [more ▼]

The Gaia satellite will be launched at the end of 2011. It will observe at least 1 billion stars, and among them several million emission line stars and hot stars. Gaia will provide parallaxes for each star and spectra for stars till V magnitude equal to 17. After a general description of Gaia, we present the codes and methods, which are currently developed by our team. They will provide automatically the astrophysical parameters and spectral classification for the hot and emission line stars in the Milky Way and other close local group galaxies such as the Magellanic Clouds. [less ▲]

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See detailGaia spectroscopy: processing, performances and scientific returns
Katz, D.; Cropper, M.; Meynadier, F. et al

in EAS Publication Series (2011, February 01)

During the five years of the mission, the Gaia spectrograph, the Radial Velocity Spectrometer (RVS) will repeatedly survey the celestial sphere down to magnitude V ~ 17-18. This talk presents: (i) the ... [more ▼]

During the five years of the mission, the Gaia spectrograph, the Radial Velocity Spectrometer (RVS) will repeatedly survey the celestial sphere down to magnitude V ~ 17-18. This talk presents: (i) the system which is currently developed within the Gaia Data Processing and Analysis Consortium (DPAC) to reduce and calibrate the spectra and to derive the radial and rotational velocities, (ii) the RVS expected performances and (iii) scientific returns. [less ▲]

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See detailGaïa, le stress géoclimatique et la peau.
Pierard, Sébastien ULg; Noel, Fanchon; Franchimont, Claudine ULg et al

in Dermo'Sphère (2010), 2

Le Soleil est à l’origine de la vie sur Terre. Le grand ensemble d’interactions biogéochimiques entre la vie, le sol, l’atmosphère et l’océan n’est pas sans rappeler la physiologie d’un grand organisme ... [more ▼]

Le Soleil est à l’origine de la vie sur Terre. Le grand ensemble d’interactions biogéochimiques entre la vie, le sol, l’atmosphère et l’océan n’est pas sans rappeler la physiologie d’un grand organisme unique. Ce dernier a reçu le nom de Gaïa. Tout le fonctionnement de la biosphère qui en fait partie est largement dépendant de l’apport énergétique solaire. Celui-ci est diversifié car le spectre des rayonnements électromagnétiques est large et variable en intensité et en nature. Le réchauffement global de la Terre et le « trou d’ozone » sont sous les feux de l’actualité. De tels bouleversements sont-ils la préfiguration d’une apocalypse ? L’écologie et la dérive géoclimatique vont-elles influencer la dermatologie de demain ? [less ▲]

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See detailGaia, lumière et biosphère.
Hermanns, Jean-François ULg; Hermanns-Le, Trinh ULg; Pierard, Gérald ULg

in Revue Médicale de Liège (2005), 60 Suppl 1

Some aspects of life are tightly bound to light exposure. Photosynthesis, chronobiology and various manifestations of the socio-cultural behaviour are typical examples.

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See detailGAIMS: A Reliable Non-Intrusive Gait Measuring System
Pierard, Sébastien ULg; Azrour, Samir ULg; PHAN BA, Remy ULg et al

in ERCIM News (2013), 95

Gait observation and analysis can provide invaluable information about an individual [1]. Studies that have interpreted gait using traditional imaging devices have demonstrated that it is difficult to ... [more ▼]

Gait observation and analysis can provide invaluable information about an individual [1]. Studies that have interpreted gait using traditional imaging devices have demonstrated that it is difficult to make reliable measurements with colour cameras. GAIMS, our new system resulting from a multidisciplinary project born from collaboration between engineers and neurologists, aims at developing non-intrusive and reliable tools to provide quantitative measures of gait and interpretations of the acquired data. Following a current trend in imaging, it takes advantage of imaging sensors that measure distance instead of colour. While its principles are general, GAIMS is currently used for the diagnosis of multiple sclerosis (MS) and the continued evaluation of disease progression [2]. It is the first available system to fully satisfy the clinical routine and its associated constraints. [less ▲]

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See detailGain baro-réflexe calculé lors d’un test d’orthostatisme (« squatting ») : reproductibilité et effet de l’âge dans une population normale
PHILIPS, Jean-Christophe ULg; MARCHAND, Monique ULg; Estrella, F. et al

in Archives des Maladies du Coeur et des Vaisseaux (2004), 97(suppl), 5392

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See detailGain-scheduled, model-based anti-windup for LPV systems
Forni, Fulvio ULg; Galeani, Sergio

in Automatica (2010), 46(1), 222-225

The aim of this paper is to show that a recently proposed technique for anti-windup control of exponentially unstable plants can be easily extended to solve the corresponding robust anti-windup problem ... [more ▼]

The aim of this paper is to show that a recently proposed technique for anti-windup control of exponentially unstable plants can be easily extended to solve the corresponding robust anti-windup problem for linear parameter varying systems, for which the time varying parameters are measured online. The proposed technique is minimally conservative with respect to the size of the resulting operating region (which coincides, up to an arbitrarily small quantity, with the largest set on which asymptotic stability can be guaranteed for the considered plant with the given saturation level and uncertainty characteristics), and is not limited to plants having only small uncertainties or being open-loop stable. [less ▲]

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See detailGaining speed in molecular dynamics simulations by implicit representation of water and membrane molecules
Steinhauer, Sven ULg; Crowet, Jean-Marc ULg; Brasseur, Robert ULg et al

Poster (2013, June 19)

Molecular dynamics (MD) is an appropriate method for investigation of peptide-membrane systems and helps in analyzing results from experiments. In many cases, the ability of viral fusion proteins and ... [more ▼]

Molecular dynamics (MD) is an appropriate method for investigation of peptide-membrane systems and helps in analyzing results from experiments. In many cases, the ability of viral fusion proteins and toxins for destabilizing the membrane is due to their hydrophobic profile, leading to particular membrane insertion. By now, many relevant processes for drug design, toxicological studies and other fields of application, are not feasible by MD simulations, when each atom is represented over time. Processes such as protein folding, often take place above the time scales reachable by MD simulations, which are of the order of micro seconds. The necessary time effort for carrying out such simulations stays considerable and depends mainly on (1) the complexity of the simulated system (2) the simulated time scale (3) the simulation method (4) the efficiency of used hardware and software algorithms. Nowadays, MD simulations can still take weeks of calculation on high end computers. Impala is an implicit water and lipids forcefield, initially developed by our laboratory. Implicit forcefields replace water and/or lipid molecules by a couple of simple and partially precalculable equations. Using this method, thousands of water and lipid molecules can be replaced in MD simulations using Gromacs software. This leads to a considerable reduction of system complexity. The original Impala algorithm based on the assumption of rigid peptides and used a Monte Carlo algorithm with the aim of finding the insertion characteristics of these molecules in membranes. Our current work is the integration of the Impala forcefield into Gromacs, a freely accessible MD software. Replacing the aqueous and lipid phase atomic description in Gromacs MD by an implicit forcefield is supposed to lead to a gain of speed compared to full atomistic simulations. A gain of precision compared to Impala is expected, too. This will be achieved by turning molecules flexible, when implementing Impala into Gromacs. [less ▲]

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See detailGains d’efficience : La Cour AELE, peu sensible à l’approche économique, rejette le pourvoi de la poste norvégienne, condamnée à 12 millions d’euros d’amendes pour avoir empêché l’accès d’entreprises concurrentes au marché de la distribution de colis aux particuliers
Sibony, Anne-Lise ULg

in Concurrences : Revue des Droits de la Concurrence (2012), 4

Cour AELE, 18 avril 2012, Posten Norge/Autorité AELE, aff. E-15/10 Gains d’efficience : La Cour AELE, peu sensible à l’approche économique, rejette le pourvoi de la poste norvégienne, condamnée à 12 ... [more ▼]

Cour AELE, 18 avril 2012, Posten Norge/Autorité AELE, aff. E-15/10 Gains d’efficience : La Cour AELE, peu sensible à l’approche économique, rejette le pourvoi de la poste norvégienne, condamnée à 12 millions d’euros d’amendes pour avoir empêché l’accès d’entreprises concurrentes au marché de la distribution de colis aux particuliers. [less ▲]

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See detailGaio, l'insegnamento e il Belgio
Gerkens, Jean-François ULg

Conference (2012, June 11)

What was the impact of the discovery of the Veronese Palimpsest on the teaching methods in Belgium?

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See detailGait analysis during an original walking test
Croisier, Jean-Louis ULg; Crielaard, Jean-Michel ULg; Chapelier, Dominique et al

in Parkinsonism & Related Disorders (2008), 14

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See detailGait analysis during an original walking test: application in fibromyalgia syndrome
Maquet, Didier ULg; Chapelier, Dominique; Bouquegneau, Adeline ULg et al

in Journal of Rehabilitation Medicine Supplement (2008, June), 47

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