References of "2002"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailPolyester layered silicate nanohybrids by controlled grafting polymerization
Lepoittevin, Bénédicte; Pantoustier, Nadège; Alexandre, Michaël ULg et al

in Journal of Materials Chemistry (2002), 12(12), 3528-3535

Poly( epsilon-caprolactone) (PCL) layered silicate nanohybrids were synthesized by ring opening polymerization of epsilon-caprolactone according to a well-controlled coordination-insertion mechanism ... [more ▼]

Poly( epsilon-caprolactone) (PCL) layered silicate nanohybrids were synthesized by ring opening polymerization of epsilon-caprolactone according to a well-controlled coordination-insertion mechanism. Montmorillonites were surface-modified by non functional (trimethylhexadecylammonium) and hydroxy functional alkylammonium cations, i.e., (2-hydroxyethyl) dimethylhexadecylammonium. The hydroxy functions available at the clay surface were activated into tin( II or IV) or Al(III) alkoxide initiators for lactone polymerization, thus yielding surface-grafted PCL chains. The surface-grafted PCL chains were recovered by an ionic exchange reaction with lithium chloride and they were analyzed by size exclusion chromatography. The PCL molar mass was measured as a function of the hydroxy content of the clay that was modulated by exchanging the Na cations with mixtures of non-functional and hydroxy functional ammonium cations of different compositions. Nanohybrids were also characterized by small-angle X-ray diffraction, transmission electron microscopy and thermogravimetry. The PCL molar mass and the nanocomposite morphology (i.e., exfoliation and/or intercalation) were readily tuned by the content of the hydroxy groups available at the clay surface. Surface-grafted aluminium trialkoxide species proved highly efficient in initiating polymerization that leads to PCL chains of controlled molar mass and narrow molecular weight distribution with polydispersity indices as low as 1.2. [less ▲]

Detailed reference viewed: 17 (0 ULg)
Full Text
See detailOntología y fenomenología en el pensamiento de Saussure
Badir, Sémir ULg

in Topicos del Seminario (2002), 8

Detailed reference viewed: 11 (0 ULg)
Peer Reviewed
See detailLinguaggio e visione: note sulle preposizioni
Boccaccini, Federico ULg

Conference (2002)

Detailed reference viewed: 12 (1 ULg)
Full Text
Peer Reviewed
See detailRelationship between markers of blood oxidant status and physiological variables in healthy and heaves-affected horses after exercise
Kirschvink, Nathalie; Art, Tatiana ULg; de Moffarts, Brieuc et al

in Equine Veterinary Journal. Supplement (2002), 34

Exercise-induced oxidative stress is investigated as a potential performance-limiting factor in human sports medicine. Therefore, the present study aimed to assess whether physiological variables that ... [more ▼]

Exercise-induced oxidative stress is investigated as a potential performance-limiting factor in human sports medicine. Therefore, the present study aimed to assess whether physiological variables that change with exercise intensity were correlated with blood oxidant markers in healthy and heaves-affected horses. Seven healthy horses, 8 heaves-affected in remission and 7 heaves-affected in crisis performed a standardised exercise test (SET) of stepwise increasing intensity. Variables monitored during exercise were heart rate (HR), venous plasma lactate (LA), packed cell volume (PCV) and arterial oxygen tension (PaO2). Oxidant markers (uric acid [UA], 8-iso-PGF2alpha and reduced [GSH] and oxidised glutathione [GSSG]) were analysed in venous peripheral blood sampled at rest (R), at peak-exercise intensity (Emax), 15 (E15) and 60 (E60) min after SET. There was a significant effect of heaves on oxidant markers and, therefore, correlation analyses between physiological variables and oxidant markers were performed separately per horse group. In healthy horses, UA analysed at Emax was positively correlated with LA. Furthermore, GSH analysed at Emax and E15 was positively correlated with PaO2. In healthy and heaves-affected horses in remission, GSH and GSSG determined at Emax were negatively correlated with HR. There was no significant correlation between 8-iso-PGF2alpha and physiological variables. In conclusion, a correlation between the physiological response to exercise and some oxidant markers exists in healthy horses. However, in heaves-affected horses the blood oxidant status is probably more dependant on airway disease than on exercise. Future studies should be undertaken to assess whether antioxidant supplementation might positively influence the oxidant-antiodidant balance in exercising horses. [less ▲]

Detailed reference viewed: 9 (3 ULg)
Full Text
Peer Reviewed
See detailC.R. de P.T. Ricketts et al., Concordance de l’occitan médiéval (COM)
Henrard, Nadine ULg

in Moyen Age (Le) (2002), CVIII(2), 384-386

Detailed reference viewed: 12 (0 ULg)
Full Text
Peer Reviewed
See detailDetermination of affinity, stoichiometry and sequence selectivity of minor groove binder complexes with double-stranded oligodeoxynucleotides by electrospray ionization mass spectrometry
Rosu, Frédéric ULg; Gabelica, Valérie ULg; Houssier, Claude ULg et al

in Nucleic Acids Research (2002), 30(16), 82

Electrospray mass spectrometry was evaluated regarding the reliability of the determination of the stoichiometries and equilibrium association constants from single spectra. Complexes between minor groove ... [more ▼]

Electrospray mass spectrometry was evaluated regarding the reliability of the determination of the stoichiometries and equilibrium association constants from single spectra. Complexes between minor groove binders (Hoechst 33258, Hoechst 33342, DAPI, netropsin and berenil) and 12mer oligonucleotide duplexes with a central sequence (A/T)(4) flanked by G/C base pairs were chosen as model systems. To validate the electrospray ionization mass spectrometry (ESI-MS) method, comparisons were made with circular dichroism and fluorescence spectroscopy measurements. ESI-MS allowed the detection of minor (2 drug + DNA) species for Hoechst 33258, Hoechst 33342, DAPI and berenil with duplex d(GGGG(A/T)(4)GGGG). d(CCCC(A/T)(4)CCCC), which were undetectable with the other techniques. Assuming that the duplexes and the complexes have the same electrospray response factors, the equilbrium association constants of the 1:1 and 2:1 complexes were determined by ESI-MS, and the values show a good quantitative agreement with fluorescence determined constants for Hoechst 33258 and Hoechst 33342. It is also shown that ESI-MS can quickly give reliable information on the A/T sequence selectivity of a drug: the signal of a complex is directly related to the affinity of the drug for that particular duplex. The potential of ESI-MS as a qualitative and quantitative affinity screening method is emphasized. [less ▲]

Detailed reference viewed: 53 (5 ULg)
Full Text
Peer Reviewed
See detailFirst synthesis of a '1,2-diquinone-calix[4]arene'. Interaction of its reduced form with Ag+
Vataj, Rame; Ridaoui, Hassan; Louati, Alain et al

in Journal of Electroanalytical Chemistry (2002), 519(1-2), 123129

Electrochemical oxidation of 5,11,17,23-tetra-tert-butyl-25,26-bis(diphenylphosphinoylmethoxy)-27,28-dihydroxycalix[4]arene (3), a calixarene with two phosphoryl units appended on proximal positions ... [more ▼]

Electrochemical oxidation of 5,11,17,23-tetra-tert-butyl-25,26-bis(diphenylphosphinoylmethoxy)-27,28-dihydroxycalix[4]arene (3), a calixarene with two phosphoryl units appended on proximal positions, affords the corresponding '1,2-diquinonecalix[4]arene' (4). The formation of 4 results from nucleophilic attack of residual water on anodically generated diphenoxylium. cations. Preliminary voltammetric experiments in CH3CN on a platinum electrode showed that 4 is suitable for electrochemical detection of the silver metal cation. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

Detailed reference viewed: 103 (6 ULg)
Full Text
See detailEvidence For a Self-Enrichment Process in Galactic Halo Globular Clusters
Parmentier, G.; Jehin, Emmanuel ULg; Magain, Pierre ULg et al

in Grebel, E.; Bradner, W. (Eds.) Modes of Star Formation and the Origin of Field Populations (2002)

Not Available

Detailed reference viewed: 11 (4 ULg)
See detailLa nitrification dans le cadre du traitement des eaux usées: production de nitrites, préservation des nitrifiants et effet d'un support
Malchair, Sandrine ULg

Master's dissertation (2002)

Le monde actuel est confronté à de nombreux problèmes environnementaux résultant des activités anthropiques. Parmi ceux-ci se pose le problème de la pollution de l’eau. Veiller au maintien de la qualité ... [more ▼]

Le monde actuel est confronté à de nombreux problèmes environnementaux résultant des activités anthropiques. Parmi ceux-ci se pose le problème de la pollution de l’eau. Veiller au maintien de la qualité de l’eau devient une nécessité pour les sociétés humaines. Ce mémoire s’inscrit dans le cadre du traitement des eaux usées. Nous avons étudié le processus de nitrification, qui associé à la dénitrification, permet de diminuer l’impact de la pollution par l’azote. Ce mémoire s’inscrit dans le cadre d’un projet de la région wallonne qui étudie l’élimination de la charge azotée des eaux usées d’origine agricole par dans une première phase, le développement d’un procédé biotechnologique permettant de produire préférentiellement des nitrites ; pour ensuite, éliminer ceux-ci par dénitrification. La nitrification peut être définie comme étant la transformation biologique de composés organiques et inorganiques (NH4+) d’une forme réduite en forme plus oxydée (NO2-, NO3-). Ce processus peut être le fait d’organismes autotrophes et hétérotrophes. La présence de nitrate dans les cours d’eau peut provoquer l’eutrophisation de ces systèmes aquatiques entraînant des conditions anoxiques et la diminution de la diversité. Ce mémoire est composé de trois chapitres traitant chacun un aspect de la nitrification dans le traitement des eaux usées. Le premier chapitre tente de déterminer les conditions du milieu favorisant les bactéries responsables de la nitritation. Pour cela, des systèmes d’étude en continu sont mis en place. Lors de cette expérience, il est apparu nécessaire de toujours disposer d’inocula stables. C’est pourquoi, dans le second chapitre, nous avons testé différentes méthodes de préservation des populations bactériennes. Le dernier chapitre de ce mémoire étudie l’effet de différents supports sur la nitrification. Dans le premier volet de ce mémoire, les systèmes de culture en continu ont permis d’établir les conditions du milieu favorables à la production de nitrites. Ces conditions sont les suivantes : Concentration en N-NH4+ de 300 mg N/l, pH de 8.2 ± 0.2, température de 30°C et concentration en oxygène dissous inférieure à 2mg/l. Les paramètres les plus importants pour favoriser les populations bactériennes oxydant l’ammonium sont le pH et la teneur en oxygène dissous. Nous avons mis en évidence que les fluctuations de pH sont néfastes pour le maintien de la nitritation. Les teneurs en oxygènes dissous faibles (inférieures à 2mg/l) stimulent les bactéries oxydant l’ammonium mais n’affectent pas celles qui oxydent les nitrites. Le second volet de ce mémoire étudie les méthodes de préservation de la population nitrifiante afin d’envisager la méthode de stockage adéquate permettant à ces populations de maintenir leur activité nitrifiante. Les différentes méthodes de conservation envisagées sont les suivantes : conservation à court terme à 4°C, conservation à plus long terme à -20°C, -80°C ou par lyophilisation, en présence ou en absence de cryoprotecteurs (DMSO et glycérol). Il apparaît que les traitements employés ont des effets significatifs sur les taux de production de nitrites plus nitrates (p<0.05). La lyophilisation ne semble pas être une technique adéquate pour la préservation des nitrifiants. L’emploi de DMSO comme cryoprotecteur semble plus adéquat que l’emploi de glycérol. La conservation à court terme à 4°C semble appropriée aux nitrifiants. A plus long terme, la conservation à -80°C en présence de DMSO semble la plus adéquate aux populations de bactéries nitrifiantes. Le dernier volet de ce mémoire envisage l’effet d’un support sur la nitrification. Notre hypothèse de départ était que la présence d’un support favorise la nitrification. Dans le sol, les bactéries se lient fortement aux argiles. Nous avons utilisé quatre argiles comme support dans cette expérience. Nous avons employé, également des cubes de mousses de polyuréthane (grande surface pour que les bactéries se fixent) et de la craie (tamponner le milieu). Les traitements envisagés n’ont aucun effet significatif sur la production de nitrites plus nitrates (p> 0.05). Notre hypothèse de départ a été infirmée. Cependant, aucune inhibition due à la présence du support sur la nitrification n’est observée. En conclusion, nous pouvons dire qu’il est possible en ajustant le pH et la teneur en oxygène dissous de favoriser les populations de bactéries oxydant l’ammoniac et donc la production de nitrites. Les conservations à court et à long terme de populations nitrifiantes sont envisageables. La présence de support a maintenu la nitrification à un taux identique à celui observé pour des populations témoins sans support. Malgré leurs propriétés respectives, aucun support testé n’a favorisé la nitrification. [less ▲]

Detailed reference viewed: 102 (3 ULg)
See detailChandra X-ray Observations of the Jovian System
Elsner, R. F.; Waite, J. H.; Crary, F. et al

Conference (2002)

High-spatial resolution Chandra x-ray obsrvations have demonstrated that most of Jupiter's northern auroral x-rays come from a hot spot located significantly poleward of the latitudes connected to the ... [more ▼]

High-spatial resolution Chandra x-ray obsrvations have demonstrated that most of Jupiter's northern auroral x-rays come from a hot spot located significantly poleward of the latitudes connected to the inner magnetosphere. This hot spot appears fixed in magnetic latitude and longitude and coincides with a region exhibiting anomalous ultraviolet and infrared emissions. The hot spot also exhibited approximately 45 minute quasi-periodic oscillations, a period similar to those reported for high-latitude radio and energetic electron bursts observed by near-Jupiter spacecraft. These results invalidate the idea that jovian auroral x-ray emissions are mainly excited by steady precipitation of energetic heavy ions from the inner magnetosphere. Instead, the x-rays appear to result from currently unexplained processes in the outer magnetosphere that produce highly localized and highly variable emissions over an extremely wide range of wavelengths. The Chandra observations also revealed for the first time x-ray emission (about 0.1 GW) from the Io Plasma Torus, as well as very faint x-ray emission (about 1-2 MW) from the Galilean moons Io, Europa, and possibly Ganymede. The emission from the moons is almost certainly due to Kalpha emission of surface atoms (and possibly impact atoms) excited by the impact of highly energetic protons, oxygen, and sulfur atoms and ions from the Torus. The Torus emission is less well understood at present, although bremsstrahlung from the non-thermal tail of the electron distribution may provide a significant fraction. In any case, further observations, already accepted and in the process of being planned, with Chandra, some with the moderate energy resolution of the CCD camera, together with simultaneous Hubble Space Telescope observations and hopefully ground-based IRTF observations should soon provide greater insight into these various processes. [less ▲]

Detailed reference viewed: 4 (0 ULg)
Full Text
Peer Reviewed
See detailAutonomie corporelle de la personne et responsabilité médicale
Leleu, Yves-Henri ULg; Genicot, Gilles ULg

in Revue de Jurisprudence de Liège, Mons et Bruxelles (2002), liv. 13

Detailed reference viewed: 38 (2 ULg)
Full Text
See detailCompte rendu de V. de Coorebyter, Sartre face à la phénoménologie
Cormann, Grégory ULg

in Revue Philosophique de Louvain (2002), 1-2

Detailed reference viewed: 38 (1 ULg)
See detailLa gestion de l'agressivité dans le cadre des relations familiales
Naziri, Despina ULg

Conference given outside the academic context (2002)

Detailed reference viewed: 6 (2 ULg)
Full Text
Peer Reviewed
See detailCombining problem structure and basis reduction to solve a class of hard integer programs
Louveaux, Quentin ULg; Wolsey, Laurence A.

in Mathematics of Operations Research (2002), 27(3), 470-484

We consider a hard integer programming problem that is difficult for the standard branch-and-bound approach even for small instances. A reformulation based on lattice basis reduction is known to be more ... [more ▼]

We consider a hard integer programming problem that is difficult for the standard branch-and-bound approach even for small instances. A reformulation based on lattice basis reduction is known to be more effective. However the step to compute the reduced basis, even if it is found in polynomial time, becomes a bottleneck for small to medium instances. By using the structure of the problem, we show that we can decompose the problem and obtain the basis by taking the kronecker product of two smaller bases easier to compute. Furthermore, if the two small bases are reduced, the kronecker product is also reduced up to a reordering of the vectors. Computational results show the gain from such an approach. [less ▲]

Detailed reference viewed: 61 (15 ULg)
Full Text
See detailDrugs and crime deviant pathways
Born, Michel ULg; Gavray, Claire ULg

in Brochu, S.; Da Agra, C.; Cousineau, M. (Eds.) Deviant trajectories at the turning point between adolescence and adulthood (2002)

Detailed reference viewed: 26 (3 ULg)
Full Text
Peer Reviewed
See detailSingle step synthesis of metal catalysts supported on porous carbon with controlled texture
Job, Nathalie ULg; Ferauche, fabrice; Pirard, René ULg et al

in Studies in Surface Science and Catalysis (2002), 143

Detailed reference viewed: 11 (1 ULg)
Full Text
See detailUn incunable de la bibliothèque de Liévin Torrentius (1525-1595) retrouvé (Bruxelles, Bibliothèque Royale, Réserve Précieuse, INC B 1192)
Adam, Renaud ULg

in Bulletin de la Société Royale Le Vieux-Liège (2002), 14(11-12), 335-337

Detailed reference viewed: 11 (0 ULg)