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See detailMetallicity Gradients in Globular Cluster Systems : the Trace of a Self-Enrichment Process ?
Parmentier, G.; Magain, Pierre ULg; Noels-Grötsch, Arlette ULg et al

in Geisler, E. K.; Grebel, E.; Minniti, D. (Eds.) Extragalactic Star Clusters (2002)

We have developed a model of globular cluster self-enrichment, based on the ability of the globular cluster gaseous progenitors to retain the ejecta of a first generation of Type II Supernovae. The key ... [more ▼]

We have developed a model of globular cluster self-enrichment, based on the ability of the globular cluster gaseous progenitors to retain the ejecta of a first generation of Type II Supernovae. The key point is that this ability depends on the pressure exerted on the progenitor cloud by the surrounding protogalactic medium and therefore on the location of the cloud in the protogalaxy. The model is able to explain the galactic halo metallicities and the metallicity gradient of the Old Halo which is thought to be the genuine galactic globular cluster system. The possibility that metallicity gradients are a common property of extragalactic globular cluster systems is also presented. [less ▲]

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See detailA metallo-beta-lactamase enzyme in action: Crystal structures of the monozinc carbapenemase CphA and its complex with biapenem
Garau, Gianpiero; Bebrone, Carine ULg; Anne, Christine et al

in Journal of Molecular Biology (2005), 345(4), 785-795

One strategy developed by bacteria to resist the action of beta-lactam antibiotics is the expression of metallo-beta-lactamases. CphA from Aeromonas hydrophila is a member of a clinically important ... [more ▼]

One strategy developed by bacteria to resist the action of beta-lactam antibiotics is the expression of metallo-beta-lactamases. CphA from Aeromonas hydrophila is a member of a clinically important subclass of metallo-beta-lactamases that have only one zinc ion in their active site and for which no structure is available. The crystal structures of wild-type CphA and its N220G mutant show the structural features of the active site of this enzyme, which is modeled specifically for carbapenem hydrolysis. The structure of CphA after reaction with a carbapenem substrate, biapenem, reveals that the enzyme traps a reaction intermediate in the active site. These three X-ray structures have allowed us to propose how the enzyme recognizes carbapenems and suggest a mechanistic pathway for hydrolysis of the beta-lactam. This will be relevant for the design of metallo-beta-lactamase inhibitors as well as of antibiotics that escape their hydrolytic activity. (C) 2004 Elsevier Ltd. All rights reserved. [less ▲]

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See detailMetallo-beta-lactamases (classification, activity, genetic organization, structure, zinc coordination) and their superfamily
Bebrone, Carine ULg

in Biochemical Pharmacology (2007), 74(12), 1686-1701

One strategy employed by bacterial strains to resist beta-lactam antibiotics is the expression of metallo-beta-lactamases requiring Zn+2 for activity. In the last few years, many new zinc beta-lactamases ... [more ▼]

One strategy employed by bacterial strains to resist beta-lactam antibiotics is the expression of metallo-beta-lactamases requiring Zn+2 for activity. In the last few years, many new zinc beta-lactamases have been described and several pathogens are now known to synthesize members of this class. Metallo-beta-lactamases are especially worrisome due to: (1) their broad activity profiles that encompass most beta-lactam antibiotics, including the carbapenems; (2) potential for horizontal transference; and (3) the absence of clinically useful inhibitors. on the basis of the known sequences, three different lineages, identified as subclasses B1, B2, and B3 have been characterized. The three-dimensional structure of at least one metallo-p-lactamase of each subclass has been solved. These very similar 3D structures are characterized by the presence of an alpha beta beta alpha-fold. In addition to metallo-beta-lactamases which cleave the amide bond of the beta-lactam ring, the metallo-beta-lactamase superfamily includes enzymes which hydrolyze thiol-ester, phosphodiester and sulfuric ester bonds as well as oxydoreductases. Most of the 6000 members of this superfamily share five conserved motifs, the most characteristic being the His116-X-His118-X-Asp120-His121 signature. They all exhibit an alpha beta beta alpha-fold, similar to that found in the structure of zinc beta-lactamases. Many members of this superfamily are involved in mRNA maturation and DNA reparation. This fact suggests the hypothesis that metallo-beta-lactamases may be the result of divergent evolution starting from an ancestral protein which did not have a beta-lactamase activity. (c) 2007 Elsevier Inc. All rights reserved. [less ▲]

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See detailMetallo-beta-lactamases as emerging resistance determinants in Gram-negative pathogens: open issues
Cornaglia, G.; Akova, M.; Amicosante, G. et al

in International Journal of Antimicrobial Agents (2007), 29(4), 380-388

The rapid spread of acquired metallo-beta-lactamases (MBLs) among major Gram-negative pathogens is a matter of particular concern worldwide and primarily in Europe, one of first continents where the ... [more ▼]

The rapid spread of acquired metallo-beta-lactamases (MBLs) among major Gram-negative pathogens is a matter of particular concern worldwide and primarily in Europe, one of first continents where the emergence of acquired MBLs has been reported and possibly the geographical area where the increasing diversity of these enzymes and the number of bacterial species affected are most impressive. This spread has not been paralleled by accuracy/standardisation of detection methods, completeness of epidemiological knowledge or a clear understanding of what MBL production entails in terms of clinical impact, hospital infection control and antimicrobial chemotherapy. A number of European experts in the field met to review the current knowledge on this phenomenon, to point out open issues and to reinforce and relate to one another the existing activities set forth by research institutes, scientific societies and European Union-driven networks. (c) 2006 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved. [less ▲]

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See detailMetallo-supramolecular micellar gels: a structural study
Mugemana, Clément; Joset, Arnaud ULg; Guillet, Pierre et al

Conference (2013, May 17)

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See detailMetallo-supramolecular micellar gels: a structural study
Mugemana, Clément; Joset, Arnaud ULg; Guillet, Pierre et al

Poster (2013, July 10)

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See detailMetallocene catalyzed polymerization of ethylene in the presence of graphite. 1. Synthesis and characterization of the composites
Alexandre, Michaël ULg; Pluta, Miroslaw; Dubois, Philippe ULg et al

in Macromolecular Chemistry and Physics (2001), 202(11), 2239-2246

Polyethylene/graphite composites have been prepared by two different methods. In a first approach, the ethylene polymerization has been catalyzed by metallo-cene in the presence of neat graphite particles ... [more ▼]

Polyethylene/graphite composites have been prepared by two different methods. In a first approach, the ethylene polymerization has been catalyzed by metallo-cene in the presence of neat graphite particles (NGC composites). A second series of composites (TGC) has been prepared by the polymerization-filling technique, which requires that the metallocene/methylalumoxane catalyst is fixed onto the graphite surface prior to the ethylene polymerization. The two series of composites exhibit significantly different morphology and thermal properties. The filler distribution is very heterogeneous in the NGC series. The morphology changes from an intimate mixture of PE and filler particles at low graphite content to graphite covered by patches of PE at high filler loading. The graphite distribution is much more homogeneous in the TGC samples, and the morphology consists of particles covered by a layer of PE in the whole composition range. Differences in the thermal properties are discussed in relation to the morphology. [less ▲]

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See detailMetallocene catalyzed polymerization of ethylene in the presence of graphite. 2. Structure and electrical properties of the composites
Pluta, Miroslaw; Alexandre, Michaël ULg; Blacher, Silvia ULg et al

in Polymer (2001), 42(22), 9293-9300

Structure and electrical properties of conducting polyethylene/graphite composites have been studied in relation to the preparation method, i.e. (i) the polymerization-filling technique (PFT), in which ... [more ▼]

Structure and electrical properties of conducting polyethylene/graphite composites have been studied in relation to the preparation method, i.e. (i) the polymerization-filling technique (PFT), in which the polyolefinic chains are growing from the graphite surface, (ii) the slurry polymerization of ethylene in the presence of untreated graphite, and (iii) the mechanical blending of preformed polyethylene and graphite. The extent of the filler dispersion depends on the method used for the composite preparation. Moreover, the graphite particles can be oriented by the molding of the samples used for the measurement of the electrical properties. This orientation is as pronounced as the melt viscosity of polyethylene is low, this characteristic feature changing with the preparation method. These structural details have consequences on the electrophysical properties and the percolation threshold. Finally, the thermal dependence of the electrical resistivity has been studied. [less ▲]

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See detailMetallographic analysis and damage characterization of Pt-Rh alloy
Reginster, Sylvie ULg

Conference given outside the academic context (2014)

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See detailthe metalloproteinase ADAM-12 regulates bronchial epithelial cell proliferation and apoptosis.
Rocks, Natacha ULg; Estrella, C.; Paulissen, Geneviève ULg et al

in Cell Proliferation (2008), 41(6), 988-1001

Objectives: The ADAMs (a disintegrin and metalloproteinase) enzymes compose a family of membrane-bound proteins characterized by their multi-domain structure and ADAM-12 expression is elevated in human ... [more ▼]

Objectives: The ADAMs (a disintegrin and metalloproteinase) enzymes compose a family of membrane-bound proteins characterized by their multi-domain structure and ADAM-12 expression is elevated in human non-small cell lung cancers. The aim of this study was to investigate the roles played by ADAM-12 in critical steps of bronchial cell transformation during carcinogenesis. Materials and methods: To assess the role of ADAM-12 in tumorigenicity, BEAS-2B cells were transfected with a plasmid encoding human full-length ADAM-12 cDNA, and then the effects of ADAM-12 overexpression on cell behaviour were explored. Treatment of clones with heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) neutralizing antibodies as well as an EGFR inhibitor allowed the dissection of mechanisms regulating cell proliferation and apoptosis. Results: Overexpression of ADAM-12 in BEAS-2B cells promoted cell proliferation. ADAM-12 overexpressing clones produced higher quantities of HB-EGF in their culture medium which may rely on membrane-bound HB-EGF shedding by ADAM-12. Targeting HB-EGF activity with a neutralizing antibody abrogated enhanced cell proliferation in the ADAM-12 overexpressing clones. In sharp contrast, targeting of amphiregulin, EGF or transforming growth factor-α failed to influence cell proliferation; moreover, ADAM-12 transfectants were resistant to etoposide-induced apoptosis and the use of a neutralizing antibody against HB-EGF activity restored rates of apoptosis to be similar to controls. Conclusions: ADAM-12 contributes to enhancing HB-EGF shedding from plasma membranes leading to increased cell proliferation and reduced apoptosis in this bronchial epithelial cell line. [less ▲]

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See detailMetalloproteinases and serine proteases activities in mixed spheroids of mouse B16 melanoma cells and fibroblasts
Coucke, Paul; Baramova, Eugenia; Leprince, Pierre ULg et al

in International Journal of Oncology (1994), 5

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See detailMetallothioneins in Marine Mammals
Das, Krishna ULg; Debacker, Virginie ULg; Bouquegneau, Jean-Marie ULg

in Cellular and Molecular Biology (2000), 46(2),

Metallothioneins (MTs) have been detected in livers and kidneys of 10 marine mammals species (Pinnipeds and Odontocetes). Characterization of renal MTs of striped dolphin has shown that the protein has ... [more ▼]

Metallothioneins (MTs) have been detected in livers and kidneys of 10 marine mammals species (Pinnipeds and Odontocetes). Characterization of renal MTs of striped dolphin has shown that the protein has two isoforms (MT-1 and MT-2) with a molecular weight estimated around 6,800. MT concentrations also vary widely in marine mammals tissues (from 58 to 1,200 microg x g(-1) ww) underlying the numerous parameters involved: physiological status, pregnancy, age, diet. The participation of this protein in metal detoxification has been investigated since high levels of cadmium (Cd) and mercury (Hg) have been measured in livers and kidneys of marine mammals. It has been suggested that those animals can mitigate at least in part, the toxic effects of Cd and Hg through binding to MTs. The percentage of the cytosolic Cd bound to MTs can reach almost 100%. On the contrary, the percentage of hepatic and renal Hg bound to MT is very low (generally less than 10%) and this metal is mainly associated with selenium (HgSe) under a detoxified form in the insoluble fraction of the tissues. MTs appear to play a minor role in the binding and detoxification of Hg by marine mammals. On the contrary, close and dynamic interactions occur between Cd and MTs. Cytosolic MTs appear as a potential short term way of detoxification of Cd accumulated from diet. Long-term detoxification would imply a sequestration of the metal under a precipitated form (e.g. in lysosomes). [less ▲]

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See detailMetallothioneins pattern during ontogeny of coastal dolphin, Pontoporia blainvillei, from Argentina
Polizzi, P.S.; Romero, M.B.; Chiodi Boudet, L.N. et al

in Marine Pollution Bulletin (2014)

Metallothioneins are signals of metal exposure and widely used in biomonitoring. Franciscana dolphin is an endemic cetacean from the Southwestern Atlantic Ocean, classified as Vulnerable A3d by the IUCN ... [more ▼]

Metallothioneins are signals of metal exposure and widely used in biomonitoring. Franciscana dolphin is an endemic cetacean from the Southwestern Atlantic Ocean, classified as Vulnerable A3d by the IUCN. Metallothionein, copper and zinc in Franciscana were assessed in two geographic groups; one inhabits La Plata River estuary, anthropogenically impacted, and the other inhabits marine coastal ecosystems, with negligible pollution. Despite the environment, hepatic and renal MT concentrations were similar, but there was a declining trend from early to later developmental stages. Metallothionein K/L, Cu and Zn levels corresponded to normal reported ranges. MT was not related with Cd. Fetal concentrations were higher than its mother. These results and the health status of dolphins are suggesting that MT correspond to physiological ranges for the species, and they are closely to homeostasis of Zn and Cu, according to its ontogenetic changes. The information constitutes the first MT information on Franciscana dolphin and can be considered as baseline for the species conservation. [less ▲]

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See detailMetallurgical and mechanical analysis from thixoforging steel shape
Becker, Eric; Bigot, Regis; Langlois, Laurent et al

in International Journal of Material Forming (2008), 1(1), 977-980

Since always, Industry minimizes manufacturing process plan and increases mechanical behaviour. In this topic, the thixoforging process offers important perspectives especially steel thixoforging. It is ... [more ▼]

Since always, Industry minimizes manufacturing process plan and increases mechanical behaviour. In this topic, the thixoforging process offers important perspectives especially steel thixoforging. It is on the way of industrial development between casting and forging process. Previous works have illustrated the importance many parameters such as steel grade, slide speed, slug and tool temperature on the geometry from thixoforging part and of the forming load. This paper completes the previous results. It presents an analysis from mechanical resistance of samples extracted of from thixo-extrusion parts on a high speed hydraulic press. This strength investigation is correlated with metallurgical analysis. Macrograph analyses allow identifying the material yield during the process and the different phases. [less ▲]

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See detailMetallurgical assessment of two HSS rolls grades for Hot Strip Mill
Lecomte-Beckers, Jacqueline ULg; Delaunois, Fabienne; Breyer, Jean-Pierre et al

in AISTech-Proceedings of the Iron and Steel Technology Conference (2007)

Aurora and Kosmos grades are HSS alloys used for the manufacturing of rolling mill work rolls for early finishing stands of Hot Strip Mills. Both alloys were metallurgically assessed using Electron ... [more ▼]

Aurora and Kosmos grades are HSS alloys used for the manufacturing of rolling mill work rolls for early finishing stands of Hot Strip Mills. Both alloys were metallurgically assessed using Electron Microscopy, X Rays analysis on carbides and Differential Thermal Analysis. These methods allow a better understanding of the behaviour of the studied alloys during solidification and cooling. Some mechanical tests were also performed. A connection between the laboratory results and the performance in operation of both grades is performed. The strong metallurgical differences especially as concern the nature and amount of carbides allow to explain the good behaviour in service of Aurora. [less ▲]

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See detailLa métallurgie ancienne en "Terre de Durbuy" : Utilisation des macroscories en dynamique fluviale
Houbrechts, Geoffrey ULg; Petit, François ULg

in Bulletin de la Société Géographique de Liège (2001), 40

Avant d’utiliser les scories métallurgiques comme traceur et indicateur de la compétence de l’Aisne à différents endroits de son cours, nous avons relevé les différents atouts qui ont favorisé le ... [more ▼]

Avant d’utiliser les scories métallurgiques comme traceur et indicateur de la compétence de l’Aisne à différents endroits de son cours, nous avons relevé les différents atouts qui ont favorisé le développement de la sidérurgie dans la « Terre de Durbuy » et nous avons étudié l’évolution des techniques sidérurgiques afin de mieux comprendre la genèse des scories. Dans cet article, nous étudions plus particulièrement l’évolution longitudinale de la taille des scories dans l’Aisne, entre Blier et Bomal où elle se jette dans l’Ourthe. Vu la trop grande proximité des sites de rejets, nous n’avons pu proposer qu’une vitesse minimum d’avancée de la charge de fond ; les scories prélevées nous ont cependant renseignés sur les variations de puissances spécifiques dans les différents tronçons de la rivière. [less ▲]

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See detailMetals at finite temperature: a modified smearing scheme
Verstraete, Matthieu ULg; Gonze, Xavier

in Computational Materials Science (2004), 30

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