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See detailDeep Impact at ESO Telescopes
Kaufl, Hans-Ullrich; Ageorges, Nancy; Bagnulo, Stefano et al

in The Messenger (2005), 121

This article is a first summary of the observations done with ESO telescopes and instrumentation in the context of NASA's Deep Impact (DI) space mission. The ESO observers were part of an extremely active ... [more ▼]

This article is a first summary of the observations done with ESO telescopes and instrumentation in the context of NASA's Deep Impact (DI) space mission. The ESO observers were part of an extremely active, communicative and thus successful worldwide network of observers. Through this network all information was freely exchanged and highlights are reported here as well. [less ▲]

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See detailIsotopic abundances of carbon and nitrogen in Jupiter-family and Oort Cloud comets
Hutsemekers, Damien ULg; Manfroid, Jean ULg; Jehin, Emmanuel ULg et al

in Astronomy and Astrophysics (2005), 440(Letters), 21-24

The [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]12[/SUP]C[SUP]15[/SUP]N and [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]13[/SUP]C[SUP]14[/SUP]N isotopic ratios are determined for the first time in a Jupiter-family comet, 88P ... [more ▼]

The [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]12[/SUP]C[SUP]15[/SUP]N and [SUP]12[/SUP]C[SUP]14[/SUP]N/[SUP]13[/SUP]C[SUP]14[/SUP]N isotopic ratios are determined for the first time in a Jupiter-family comet, 88P/1981 Q1 Howell, and in the chemically peculiar Oort Cloud comet C/1999 S4 (LINEAR). By comparing these measurements to previous ones derived for six other Oort Cloud comets (including one of Halley-type), we find that both the carbon and nitrogen isotopic ratios are constant within the uncertainties. The mean values are [SUP]12[/SUP]C/[SUP]13[/SUP]C ~= 90 and [SUP]14[/SUP]N/[SUP]15[/SUP]N ~=145 for the eight comets. These results strengthen the view that CN radicals originate from refractory organics formed in the protosolar molecular cloud and subsequently incorporated in comets. [less ▲]

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See detailMembrane-type 1 matrix metalloproteinase expression is regulated by zonula occludens-1 in human breast cancer cells
Polette, M.; Gilles, Christine ULg; Nawrocki-Raby, B. et al

in Cancer Research (2005), 65(17), 7691-7698

The acquisition of a migratory/invasive phenotype by tumor cells is characterized by the loss of cell-cell adhesion contacts and the expression of degradative properties. In this study, we examined the ... [more ▼]

The acquisition of a migratory/invasive phenotype by tumor cells is characterized by the loss of cell-cell adhesion contacts and the expression of degradative properties. In this study, we examined the effect of the disorganization of occludin/zomda occludens (ZO)-1 tight junction (TJ) complexes on the expression of membrane-type I matrix metalloproteinase (MT1-MMP). We first compared the expression of MT1-MMP and the localization of occludin/ZO-1 complexes in breast tumor cell lines displaying various degrees of invasiveness. We showed that the expression of MT1-MMP in invasive breast tumor cell lines correlates with the absence of occludin and with a cytoplasmic localization of ZO-1. In contrast, noninvasive cell lines displayed a membrane staining for both ZO-1 and occludin and did not express MT1-MMP. In vivo, cytoplasmic ZO-1 and MTI-MMP could be detected in invasive tumor clusters of human breast carcinomas. We then used RNA interference strategy to inhibit ZO-1 expression in invasive BT549 cells and to evaluate the effect of ZO-1 downregulation on MTI-MMP expression. We observed that ZO-1 small interfering RNA transfection down-regulates MT1-MMP mRNAs and proteins and subsequently decreases the ability of tumor cells to invade a reconstituted basement membrane in a Boyden chamber assay. Inversely, transfection of expression vectors encoding wild-type ZO-1 or the NH2-terminal fragment of ZO-1 comprising the PSD95/DLG/ZO-1 domains in BT549 activated a human MT1-MMP promoter luciferase reporter construct and increased cell invasiveness. Such transfections concomitantly activated the beta-catenin/TCF/LEF pathway. Our results therefore show that ZO-1, besides its structural role in TJ assembly, can intervene in signaling events promoting tumor cell invasion. [less ▲]

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See detailL'astronomie dans le monde
Manfroid, Jean ULg

Article for general public (2005)

Deep Impact, Mars, Le cratère Nicholson, 248 MARSIS, CLUSTER, Aurores de Saturne, Sylvia, Planète X (suite), Supernova de M51

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See detailAn asteroseismic study of the β Cephei star θ Ophiuchi: spectroscopic results
Briquet, Maryline ULg; Lefever, K.; Uytterhoeven, K. et al

in Monthly Notices of the Royal Astronomical Society (2005), 362

We present the results of a detailed analysis of 121 ground-based high-resolution, high signal-to-noise ratio spectroscopic measurements spread over 3 yr for the β Cephei star θ Ophiuchi. We discovered θ ... [more ▼]

We present the results of a detailed analysis of 121 ground-based high-resolution, high signal-to-noise ratio spectroscopic measurements spread over 3 yr for the β Cephei star θ Ophiuchi. We discovered θ Oph to be a triple system. In addition to the already known speckle B5 companion of the B2 primary, we showed the presence of a low-mass spectroscopic companion and we derived an orbital period of 56.71 d with an eccentricity of 0.1670. After removing the orbit we determined two frequencies for the primary in the residual radial velocities: f[SUB]1[/SUB]= 7.1160 cd[SUP]-1[/SUP] and f[SUB]2[/SUB]= 7.4676 cd[SUP]-1[/SUP]. We also found the presence of f[SUB]3[/SUB]= 7.3696 cd[SUP]-1[/SUP] by means of a two-dimensional frequency search across the SiIII 4567-Åprofiles. We identified the m-value of the main mode with frequency f[SUB]1[/SUB] by taking into account the photometric identifications of the degrees l. By means of the moment method and the amplitude and phase variations across the line profile, we derived (l[SUB]1[/SUB], m[SUB]1[/SUB]) = (2, -1). This result allows us to fix the mode identifications of the whole quintuplet for which three components were detected in photometry. This is of particular use for our forthcoming seismic modelling of the primary. We also determined stellar parameters of the primary by non-local thermodynamic equilibrium hydrogen, helium and silicon line profile fitting and we obtained T[SUB]eff[/SUB]= 24000 K and logg= 4.1, which is consistent with photometrically determined values. [less ▲]

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See detailChemical abundances in 43 metal-poor stars
Jonsell, K.; Edvardsson, B.; Gustafsson, B. et al

in Astronomy and Astrophysics (2005), 440

We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni, and Ba for 43 metal-poor field stars in the solar neighbourhood, most of them subgiants or turn-off-point stars with iron ... [more ▼]

We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni, and Ba for 43 metal-poor field stars in the solar neighbourhood, most of them subgiants or turn-off-point stars with iron abundances [Fe/H] ranging from -0.4 to -3.0. About half of this sample has not been spectroscopically analysed in detail before. Effective temperatures were estimated from uvby photometry, and surface gravities primarily from Hipparcos parallaxes. The analysis is differential relative to the Sun, and was carried out with plane-parallel MARCS models. Various sources of error are discussed and found to contribute a total error of about 0.1-0.2 dex for most elements, while relative abundances, such as [Ca/Fe], are most probably more accurate. For the oxygen abundances, determined in an NLTE analysis of the 7774 Å triplet lines, the errors may be somewhat larger. We made a detailed comparison with similar studies and traced the reasons for the, in most cases, relatively small differences. Among the results we find that [O/Fe] possibly increases beyond [Fe/H] = -1.0, though considerably less so than in results obtained by others from abundances based on OH lines. We did not trace any tendency toward strong overionization of iron, and find the excesses, relative to Fe and the Sun, of the alpha elements Mg, Si, and Ca to be smaller than those of O. We discuss some indications that also the abundances of different alpha elements relative to Fe vary and the possibility that some of the scatter around the trends in abundances relative to iron may be real. This may support the idea that the formation of Halo stars occurred in smaller systems with different star formation rates. We verify the finding by Gratton et al. (2003b, A&A, 406, 131) that stars that do not participate in the rotation of the galactic disk show a lower mean and larger spread in [ alpha/Fe] than stars participating in the general rotation. The latter stars also seem to show some correlation between [ alpha/Fe] and rotation speed. We trace some stars with peculiar abundances, among these two Ba stars, <ASTROBJ>HD 17072</ASTROBJ> and <ASTROBJ>HD 196944</ASTROBJ>, the second already known to be rich in s elements. Finally we advocate that a spectroscopic study of a larger sample of halo stars with well-defined selection criteria is very important, in order to add to the very considerable efforts that various groups have already made. [less ▲]

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See detailDeux ans d'analyse de saisies d'heroine en region liegeoise
Denooz, Raphael ULg; Dubois, Nathalie ULg; Charlier, Corinne ULg

in Revue Médicale de Liège (2005), 60(9), 724-8

The results of heroin analysis from seizures in the Liege area during the last two years are presented in this article. Between January 2003 and January 2005, 50 samples were analysed in the Laboratory of ... [more ▼]

The results of heroin analysis from seizures in the Liege area during the last two years are presented in this article. Between January 2003 and January 2005, 50 samples were analysed in the Laboratory of Clinical Toxicology and Forensic Toxicology of the University of Liege. Mean heroin concentration was 14,7%. Noscapine and papaverine, other opium alcaloids, were simultaneously present with heroin. As diluents, we only identified caffein and acetaminophen. [less ▲]

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See detailRole of disulfide bridges in the activity and stability of a cold-active alpha-amylase
Siddiqui, K. S.; Poljak, A.; Guilhaus, M. et al

in Journal of Bacteriology (2005), 187(17), 6206-6212

The cold-adapted alpha-amylase from Pseudoalteromonas haloplanktis unfolds reversibly and cooperatively according to a two-state mechanism at 30 degrees C and unfolds reversibly and sequentially with two ... [more ▼]

The cold-adapted alpha-amylase from Pseudoalteromonas haloplanktis unfolds reversibly and cooperatively according to a two-state mechanism at 30 degrees C and unfolds reversibly and sequentially with two transitions at temperatures below 12 degrees C. To examine the role of the four disulfide bridges in activity and conformational stability of the enzyme, the eight cysteine residues were reduced with beta-mercaptoethanol or chemically modified using iodoacetamide or iodoacetic acid. Matrix-assisted laser desorption-time of flight mass spectrometry analysis confirmed that all of the cysteines were modified. The iodoacetamide-modified enzyme reversibly folded/unfolded and retained approximately one-third of its activity. Removal of all disulfide bonds resulted in stabilization of the least stable region of the enzyme (including the active site), with a concomitant decrease in activity (increase in activation enthalpy). Disulfide bond removal had a greater impact on enzyme activity than on stability (particularly the active-site region). The functional role of the disulfide bridges appears to be to prevent the active site from developing ionic interactions. Overall, the study demonstrated that none of the four disulfide bonds are important in stabilizing the native structure of enzyme, and instead, they appear to promote a localized destabilization to preserve activity. [less ▲]

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See detailThe active site is the least stable structure in the unfolding pathway of a multidomain cold-adapted alpha-amylase
Siddiqui, K. S.; Feller, Georges ULg; D'Amico, Salvino ULg et al

in Journal of Bacteriology (2005), 187(17), 6197-6205

The cold-active alpha-amylase from the Antarctic bacterium Pseudoalteromonas haloplanktis (AHA) is the largest known multidomain enzyme that displays reversible thermal unfolding (around 30 degrees C ... [more ▼]

The cold-active alpha-amylase from the Antarctic bacterium Pseudoalteromonas haloplanktis (AHA) is the largest known multidomain enzyme that displays reversible thermal unfolding (around 30 degrees C) according to a two-state mechanism. Transverse urea gradient gel electrophoresis (TUG-GE) from 0 to 6.64 M was performed under various conditions of temperature (3 degrees C to 70 degrees C) and pH (7.5 to 10.4) in the absence or presence of Ca2+ and/or Tris (competitive inhibitor) to identify possible low-stability domains. Contrary to previous observations by strict thermal unfolding, two transitions were found at low temperature (12 degrees C). Within the duration of the TUG-GE, the structures undergoing the first transition showed slow interconversions between different conformations. By comparing the properties of the native enzyme and the N12R mutant, the active site was shown to be part of the least stable structure in the enzyme. The stability data supported a model of cooperative unfolding of structures forming the active site and independent unfolding of the other more stable protein domains. In light of these findings for AHA, it will be valuable to determine if active-site instability is a general feature of heat-labile enzymes from psychrophiles. Interestingly, the enzyme was also found to refold and rapidly regain activity after being heated at 70 degrees C for 1 h in 6.5 M urea. The study has identified. fundamental new properties of AHA and extended our understanding of structure/stability relationships of cold-adapted enzymes. [less ▲]

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See detailUsage des données 3D IGN, PICC et SETHY pour l’orthorectification d’une image QuickBird en région liégeoise.
Binard, Marc ULg

in AM/FM-GIS BELUX News (2005), 32

This paper presents the first results of the SPIDER project obtained on a VHR satellite image (QuickBird) acquired on the Liège area (315 km²). It shows how a selection of data in the Walloon cartographic ... [more ▼]

This paper presents the first results of the SPIDER project obtained on a VHR satellite image (QuickBird) acquired on the Liège area (315 km²). It shows how a selection of data in the Walloon cartographic gateway allowed the making of a DSM needed at the orthorectification of the satellite image. [less ▲]

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See detailLa création comme (seule) identité
Brausch, Géraldine ULg

in Espace de Libertés : Magazine du Centre d'Action Laïque (2005), 334

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See detailCharacterisation of an original model of myocardial infarction provoked by coronary artery thrombosis induced by ferric chloride in pig
Dogné, Jean-Michel ULg; Rolin, S.; Tchana-Sato, Vincent ULg et al

in European Heart Journal (2005, September), 26(Suppl. 1), 455-456

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See detailÉ́tude du logiciel libre – Une innovation sociale
Rieppi, Stéphane ULg

Master's dissertation (2005)

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See detailLe cas clinique du mois: traitement d'un kyste hydatique hepatique par hepatectomie laparoscopique (Bisegmentectomie II-III)
Detry, Olivier ULg; Leonard, Philippe ULg; Delwaide, Jean ULg et al

in Revue Médicale de Liège (2005), 60(9), 700-2

Most of the echinococcosis cases treated in Belgium are contracted in African and Mediterranean countries. In this paper the authors describe the case of a Mediterranean patient suffering from a hepatic ... [more ▼]

Most of the echinococcosis cases treated in Belgium are contracted in African and Mediterranean countries. In this paper the authors describe the case of a Mediterranean patient suffering from a hepatic hydatid cyst treated by oral albendazole and laparoscopic liver resection. [less ▲]

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See detailAortic valve replacement in octogenarians: operative outcome and long-term results
Kolh, Philippe ULg; Kerzmann, Arnaud ULg; Jacquart, Julie ULg et al

in European Heart Journal (2005, September), 26(Suppl. 1), 676

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See detailContribution au développement de biomarqueurs d'exposition aux PCBs chez Gammarus Pulex Linné, 1758 (Crustacé Amphipode)
Michel, Loïc ULg

Master's dissertation (2005)

Le présent travail avait pour but la mise en évidence de biomarqueurs d’exposition aux polychlorobiphényles (PCBs) chez le crustacé amphipode d’eau douce Gammarus pulex. Dans cette optique, deux ... [more ▼]

Le présent travail avait pour but la mise en évidence de biomarqueurs d’exposition aux polychlorobiphényles (PCBs) chez le crustacé amphipode d’eau douce Gammarus pulex. Dans cette optique, deux biomarqueurs potentiels ont été testés, à savoir l’activité d’une enzyme de détoxification de la phase I (l’éthoxyrésorufine-O-dééthylase, ou EROD) et l’activité d’une famille d’enzymes de détoxification de la phase II (les glutathion-S-transférases, ou GSTs). Afin de détecter une éventuelle induction de l’activité de ces enzymes chez des individus exposés aux PCBs, un protocole a été mis au point pour contaminer des gammares in vitro. Des spécimens provenant d’un site de référence faiblement contaminé, le Blanc Gravier à Colonster, ont ainsi été exposés à des congénères de PCBs utilisé seuls (congénères n° 77 ou n° 169) ou en mélange (congénères n° 28, 52, 101, 118, 138, 153 et 180). Ce protocole s’est révélé adéquat, dans la mesure où il allie une mortalité acceptable et des taux élevés d’accumulation des toxiques. Une induction significative de l’activité des GSTs a pu être mise en évidence chez les gammares exposés in vitro aux PCBs, mais aussi chez des gammares prélevés dans le milieu naturel en des sites pollués par les PCBs (Vesdre à Vaux-sous-Chèvremont, Ourthe à Angleur et Mehaigne à Wanze). Ceci nous amène à penser que l’induction de l’activité des GSTs constitue un biomarqueur d’exposition potentiel intéressant. Nous ne sommes pas parvenus à mettre au point le dosage de l’activité de l’EROD chez Gammarus pulex. Ces essais ne peuvent donc être considérés que comme une première approche, et il nous est impossible d’arriver à une conclusion concernant l’intérêt de l’induction de l’activité de l’EROD en tant que biomarqueur d’exposition aux PCBs chez Gammarus pulex. A côté de ces mesures d’activité enzymatiques, des analyses protéomiques (électrophorèse bidimensionnelle sur gel de polyacrylamide) ont également été réalisées, dans le but de détecter d’éventuelles variations d’expression protéique entre individus témoins ou contaminés in vitro par les PCBs. Ces variations pourraient, le cas échéant, être utilisées pour le développement de biomarqueurs d’exposition aux PCBs. Bien que, dans le cadre de ce mémoire, nous n’ayons pas pu mettre en évidence de différences d’expression directement imputables à l’action des toxiques, nous somme parvenus à obtenir des gels d’électrophorèse potentiellement utilisables pour l’identification des protéines contenues dans ces gels, et la méthode utilisée ici est donc susceptible d’être utilisée lors d’études ultérieures similaires. [less ▲]

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