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See detailElaboration d'outils intégrés de gestion des données topographiques et morphologiques pour la modélisation des crues et inondations
Detrembleur, Sylvain ULg

Master of advanced studies dissertation (2003)

L’activité de recherche dont bénéficie ce travail a consisté à poursuivre le développement du logiciel quasi-tridimensionnel de modélisation des écoulements de surface de la suite WOLF. Plus ... [more ▼]

L’activité de recherche dont bénéficie ce travail a consisté à poursuivre le développement du logiciel quasi-tridimensionnel de modélisation des écoulements de surface de la suite WOLF. Plus particulièrement, ce travail vise à développer et à rendre opérationnelle une filière automatique de traitement de données topographiques et morphologiques directement exploitables par WOLF2D. Ces algorithmes sont basés sur des approches hydrauliques ou sédimentaires, afin de générer une information complète sur grids réguliers organisés en blocs. Il s’agit d’exploiter des informations parcellaires, soit acquises par laser ou sonar multi-faisceaux, soit issues de campagnes plus classiques d’acquisition de profils en travers par méthodes topographiques. Une adaptation des lois classiques de frottement est également suggérée et traitée numériquement afin de tenir compte de ce nouveau type d’information très dense ainsi que des obstacles locaux constitués par les ouvrages d’art imposant des mises en charge et des pertes de charge locales. Le bien-fondé de ces développements est mis en lumière par le routage de grosses applications réelles pour lesquelles des campagnes complémentaires sur sites, l’exploitation de laisses de crue locales et des enquêtes de terrain permettent des comparaisons significatives. [less ▲]

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See detailExpression pattern of metalloproteinases and tissue inhibitors of matrix-metalloproteinases in cycling human endometrium
Goffin, Frédéric ULg; Munaut, Carine ULg; Frankenne, Francis et al

in Biology of Reproduction (2003), 69(3), 976-984

The cyclic growth, differentiation, and cell death of endometrium represents the most dynamic example of steroid-driven tissue turnover in human adults. Key effectors in these processes-matrix ... [more ▼]

The cyclic growth, differentiation, and cell death of endometrium represents the most dynamic example of steroid-driven tissue turnover in human adults. Key effectors in these processes-matrix metalloproteinases (MMPs) and their specific inhibitors (TIMPs)-are regulated by ovarian steroids and, locally, by cytokines. We used reverse transcription-polymerase chain reaction to evaluate the expression of both transcriptionally regulated molecules such as estrogen receptor-alpha, progesterone receptor, and prolactin and a large array of MMPs and TIMPs (MMP-1, -2, -3, -7, -8, -9, -11, -12, -19, -26, MT1-MMP, MT2-MMP, MT3-MMP, TIMP-1, -2, -3). Altogether, three distinct patterns of MMP and two patterns of TIMP expression were detected in cycling endometrium: 1). MMPs restricted to the menstrual period (MMPs-1, -3, -8, -9, -12); 2). MMPs and TIMPs expressed throughout the cycle (MMP-2, MT1-MMP, MT2-MMP, MMP-19, TIMP-1, and TIMP-2); 3). MMPs predominantly expressed during the proliferative phase (MMP-7, MMP-11, MMP-26, and MT3-MMP); and 4). TIMP-3, which, contrary to the other TIMPs, shows significant modulations, with maximum expression during the late secretory and menstrual phases. These specific patterns of MMP expression associated with each phase of the cycle may point to specific roles in the processes of menstruation, housekeeping activities, angiogenesis, tissue growth, and extracellular matrix remodeling. [less ▲]

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See detailStress echocardiography in horses: comparison of cardiac output during incremental dobutamine infusion in atropinised and non-atropinised ponies
Sandersen, Charlotte ULg; Detilleux, Johann ULg; Delguste, Catherine ULg et al

in Proceedings of the 42d Annual Congress of the British Equine Veterinairy Association (2003, September)

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See detailMoritella cold-active dihydrofolate reductase: Are there natural limits to optimization of catalytic efficiency at low temperature?
Xu, Y.; Feller, Georges ULg; Gerday, Charles ULg et al

in Journal of Bacteriology (2003), 185(18), 5519-5526

Adapting metabolic enzymes of microorganisms to low temperature environments may require a difficult compromise between velocity and affinity. We have investigated catalytic efficiency in a key metabolic ... [more ▼]

Adapting metabolic enzymes of microorganisms to low temperature environments may require a difficult compromise between velocity and affinity. We have investigated catalytic efficiency in a key metabolic enzyme (dihydrofolate reductase) of Moritella profunda sp. nov., a strictly psychrophilic bacterium with a maximal growth rate at 2degreesC or less. The enzyme is monomeric (M-r = 18,291), 55% identical to its Escherichia coli counterpart, and displays T-m and denaturation enthalpy changes much lower than E. coli and Thermotoga maritima homologues. Its stability curve indicates a maximum stability above the temperature range of the organism, and predicts cold denaturation below 0degreesC. At mesophilic temperatures the apparent K-m value for dihydrofolate is 50- to 80-fold higher than for E. coli, Lactobacillus casei, and T. maritima dihydrofolate reductases, whereas the apparent K-m value for NADPH, though higher, remains in the same order of magnitude. At 5degreesC these values are not significantly modified. The enzyme is also much less sensitive than its E. coli counterpart to the inhibitors methotrexate and trimethoprim. The catalytic efficiency (k(cat)/K-m) with respect to dihydrofolate is thus much lower than in the other three bacteria. The higher affinity for NADPH could have been maintained by selection since NADPH assists the release of the product tetrahydrofolate. Dihydrofolate reductase adaptation to low temperature thus appears to have entailed a pronounced trade-off between affinity and catalytic velocity. The kinetic features of this psychrophilic protein suggest that enzyme adaptation to low temperature may be constrained by natural limits to optimization of catalytic efficiency. [less ▲]

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See detailDe LAT-relatie tussen strip en literatuur. Over de 'verstripping' van literaire werken
Meesters, Gert ULg

in Ons Erfdeel (2003), 46(4), 523-530

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See detailQualitative and quantitative criteria for comfortable urban public spaces
Reiter, Sigrid ULg; De Herde, André

in Carmeliet, Jan; Hens, Hugo; Vermeir, Gerrit (Eds.) Research in building physics. Proceedings of the 2nd International Conference on Building Physics (2003, September)

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See detailInvestigation of singlet oxygen reactivity towards propofol
Heyne, Belinda; Kohnen, Stephan ULg; Brault, Daniel et al

in Photochemical & Photobiological Sciences (2003), 2(9), 939-945

The reaction between the anaesthetic agent 2,6-diisopropylphenol (propofol, PPF) and singlet oxygen (1O2) has been investigated in aqueous solution by means of HPLC, GC, absorption spectroscopy and laser ... [more ▼]

The reaction between the anaesthetic agent 2,6-diisopropylphenol (propofol, PPF) and singlet oxygen (1O2) has been investigated in aqueous solution by means of HPLC, GC, absorption spectroscopy and laser flash photolysis with infrared luminescence detection. The rate constants for the physical and chemical quenching of 1O2 by PPF (kPPF) are found to be 2.66 x 10(5) M(-1) s(-1) and approximately 3.2 x 10(6) M(-1) s(-1) in CD3OD and D2O-CD3OD (75:25 v/v), respectively. The reaction of propofol with singlet oxygen produced by light irradiation of Rose Bengal leads essentially to two reaction products, 2,6-diisopropyl-p-benzoquinone and 3,5,3',5'-tetraisopropyl-(4,4')-diphenoquinone that are unambiguously identified from comparison with authentic samples. [less ▲]

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See detailStructure of liquid semiconductors
Gaspard, Jean-Pierre ULg; Raty, Jean-Yves ULg

in Journal de Physique IV (2003), 111

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See detailThe in situ Glyptostroboxylon forest of Hoegaarden (Belgium) at the Initial Eocene Thermal Maximum (55 Ma)
Fairon-Demaret, Muriel ULg; Steurbaut, Etienne; Damblon, Freddy ULg et al

in Review of Palaeobotany and Palynology (2003), 126(1-2), 103-129

Hundreds of silicified standing stumps have been discovered within a lignitic horizon in the middle of the Tienen Formation near Hoegaarden in northeast Belgium. The anatomical features of the fossil ... [more ▼]

Hundreds of silicified standing stumps have been discovered within a lignitic horizon in the middle of the Tienen Formation near Hoegaarden in northeast Belgium. The anatomical features of the fossil stumps, as those of the numerous silicified secondary xylem remains collected since the last century from this area, demonstrate that they all belong to a single taxodiaceous taxon. The stumps bear characteristics shared by Taxodioxylon gypsaceum and Glyptostroboxylon tenerum, but affinities with the latter appear closer. They are attributed to Glyptostroboxylon sp. Calibration of the sedimentological, stratigraphical and organic carbon isotope data reveals that these taxodiaceous fossil trees developed in a swampy lowland environment most probably during the Initial Eocene Thermal Maximum at ca. 55 Ma. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

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See detailLearned material content and acquisition level modulate cerebral reactivation during posttraining rapid-eye-movements sleep
Peigneux, Philippe ULg; Laureys, Steven ULg; Fuchs, Sonia et al

in NeuroImage (2003), 20(1), 125-134

We have previously shown that several brain areas are activated both during sequence learning at wake and during subsequent rapid-eye-movements (REM) sleep (Nat. Neurosci. 3 (2000) 831-836), suggesting ... [more ▼]

We have previously shown that several brain areas are activated both during sequence learning at wake and during subsequent rapid-eye-movements (REM) sleep (Nat. Neurosci. 3 (2000) 831-836), suggesting that REM sleep participates in the reprocessing of recent memory traces in humans. However, the nature of the reprocessed information remains open. Here, we show that regional cerebral reactivation during posttraining REM sleep is not merely related to the acquisition of basic visuomotor skills during prior practice of the serial reaction time task, but rather to the implicit acquisition of the probabilistic rules that defined stimulus sequences. Moreover, functional connections between the reactivated cuneus and the striatum-the latter being critical for implicit sequence learning-are reinforced during REM sleep after practice on a probabilistic rather than on a random sequence of stimuli. Our results therefore support the hypothesis that REM sleep is deeply involved in the reprocessing and optimization of the high-order information contained in the material to be learned. In addition, we show that the level of acquisition of probabilistic rules attained prior to sleep is correlated to the increase in regional cerebral blood flow during subsequent REM sleep. This suggests that posttraining cerebral reactivation is modulated by the strength of the memory traces developed during the learning episode. Our data provide the first experimental evidence for a link between behavioral performance and cerebral reactivation during REM sleep. (C) 2003 Elsevier Inc. All rights reserved. [less ▲]

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See detailConférence citoyenne sur les tests génétiques "Lire dans mes gènes" - Rapport d'évaluation
Mormont, Marc ULg; Melard, François ULg

Report (2003)

Rapport d'évaluation sur la première conférence citoyenne nationale en Belgique (FRB). Le rapport présente les implications méthodologiques liées au fonctionnement de la conférence citoyenne.

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See detailDurability of mortars modified with metakaolin
Courard, Luc ULg; Darimont, Anne ULg; Schouterden, M. et al

in Cement & Concrete Research (2003), 33(9), 1473-1479

Results of an investigation to determine the effects of metakaolin additions on transport properties of mortars are reported. Comparisons are made to ordinary Portland cement (OPC) to determine the ... [more ▼]

Results of an investigation to determine the effects of metakaolin additions on transport properties of mortars are reported. Comparisons are made to ordinary Portland cement (OPC) to determine the influence of addition and replacement percentage. Cement is replaced on a mass basis of 5-20% for metakaolin. A mixture with natural kaolin is also studied. The transport properties and chemical behaviors are analyzed by means of chloride diffusion tests and sulfate immersion. Obserdvations after more than 100 days are used to prescribe mixtures that reduce the rate of chloride diffusion and sulfate degradation. For metakaolin, the optimum seems to be between 10% and 15% with regard to inhibition effect on chloride diffusion and sulfate attack. (C) 2003 Elsevier Ltd. All rights reserved. [less ▲]

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See detailA tool to design steel elements submitted to compartment fires - OZone V2. Part 2: Methodology and application
Cadorin, Jean-François; Pintea, Dan; Dotreppe, Jean-Claude ULg et al

in Fire Safety Journal (2003), 38(5), 429-451

The methodology implemented in the tool OZone V2 to design steel elements submitted to compartment fires is presented. Input needed to define a fire compartment are first quoted. The procedure to define ... [more ▼]

The methodology implemented in the tool OZone V2 to design steel elements submitted to compartment fires is presented. Input needed to define a fire compartment are first quoted. The procedure to define the design fire is then explained. This procedure enables to take into account the benefits of active measures on the fire safety. The combined use of a two- and a one-zone model is then presented. A particular attention is given to the criteria of choice of the model and to the different scenarios that can occur. The calculation of steel element temperature is then explained. The proposed procedure takes into account the localised effect of a fire with the help of Hasemi's model. The fire resistance is then calculated with the EUROCODE 3 methods. An application is finally presented. (C) 2003 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailEarly onset neonatal sepsis and meningitis in Belgium: a decade review
MELIN, Pierrette ULg; Maquet, Julie; Ducoffre, Geneviève et al

in American Society of Microbiology (Ed.) Program and Abstracts of the 43rd Intersciences Conference on Antimicrobial Agents and Chemotherapy (2003, September)

Background: In the late 1990s, Belgium has reached the era of “group B streptococcal (GBS) prevention” and after 1996, some institutions, but not the majority, had implemented intrapartum ... [more ▼]

Background: In the late 1990s, Belgium has reached the era of “group B streptococcal (GBS) prevention” and after 1996, some institutions, but not the majority, had implemented intrapartum antibioprophylaxis for GBS prevention. Concern exists that one unintended consequence of GBS prevention efforts through chemoprophylaxis may be an increase in the rate of serious neonatal infections due to Gram negative bacteria (GNB). To monitor trends, continued surveillance of neonatal sepsis is needed. Methods: On a weekly basis, laboratories of the Belgian sentinel network notified each case of neonatal bacteremia or meningitis occurring within 28 days after birth. We reviewed on a year-base data collected from 1991-2001 for early–onset diseases (EOD; < 5 days). Results: A yearly mean of 47 cases (24-90) were notified by 28 (16-35) laboratories. Overall GBS remained the leading cause and represented annually 37.9% (25-54.7%) of EOD and did not show significant change. It was followed by E.coli 11.4%, coagulase negative staphylococci (CNS) 11.9%, S.aureus 9.9%, Listeria sp 3.9%, S.pyogenes (GAS) 2.5%, S.pneumoniae 2.7%, H.influenzae 2.7% and others. During the decade, whereas a significant reduction in the rate of E.coli and other GNB EOD occurred (p <0.01), significant increases in the rate of EOD due to GAS (p <0.001), S.aureus (p <0.001), and CNS (p <0.01), were found. For CNS, we did not have data to distinguish definite or possible infections from contaminations. Conclusions: 1) During the last decade, GBS has remained the leading cause of neonatal EOD. 2) A decline in the rate of E.coli and other GNB infections occurred. 3) In the late 1990s, S.aureus and CNS were more frequently reported. 4) An increase in GAS occurrence was found 5) Potential change in pathogens overtime requires confirmation by ongoing surveillance. [less ▲]

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See detailAntimicrobial Susceptibilities of recent clinical isolates of group B streptococci agalactiae from Belgium
MELIN, Pierrette ULg; Maquet, Julie; Rodriguez Cuns, Grisel et al

in American Society of Microbiology (Ed.) Program and Abstracts of the 43rd Intersciences Conference on Antimicrobial Agents and Chemotherapy (2003, September)

Background: : GBS cause severe infections in neonates, pregnant women and other adults. Empiric therapy is usually started before susceptibility results are available. Early neonatal diseases can be ... [more ▼]

Background: : GBS cause severe infections in neonates, pregnant women and other adults. Empiric therapy is usually started before susceptibility results are available. Early neonatal diseases can be prevented with intrapartum antibiotic prophylaxis based on accurate susceptibility surveillance data. A previous Belgian study showed an increase of 3 to 10 % R to erythromycin (EM) through the 1990s. Methods: 187 GBS isolates consecutively received at the reference laboratory between 2001 to March 2003 were from 73 neonates (52 early-onset and 21 late-onset diseases), 52 adults and 62 from pregnant women’s vagina. MICs of penicillin (PG), EM, clindamycin (CM) and gentamicin (GM) were determined with Etest. PG MBCs were also determined by inactivating the drug in MIC plates using betalactamase. EM resistant (R) isolates were tested by the CM + EM double disk to determine macrolide R phenotypes. Results: All strains were susceptible (S) to PG and no tolerance was observed with MBCs falling within 2 dilutions of MICs. 19.2% of isolates were R to EM, with significantly more R isolates from adults (30.8%; p <0.01) and serotype V (46.8%; p <0,001). 80% had the MLSB phenotype (R to EM and CM), 16 were constitutive and 12 inducible. The M phenotype (R to EM and S to CM) was seen in 7 (20%) of isolates. Less than 10% of isolates were inhibited by GM MIC of <=64 mg/L, 83.6% by 128-256 mg/L and 2.9% by >/=512 mg/L. Non typable strains were more R to GM (p <0.01). Conclusions: 1) PG remained active against all isolates and no tolerance was seen. 2) Prevalence of R to macrolides had increased since 1999, particularly in adult isolates and serotype V. 3) Intermediate to high level R to GM was seen and potential synergy of PG + GM should be investigated. 4) R surveillance is mandatory to guide prophylaxis and treatment of serious GBS infections. [less ▲]

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See detailIncreased Mrna Expression of Decorin in the Prolapsing Posterior Leaflet of the Mitral Valve
Radermecker, M. A.; Limet, Raymond ULg; Lapiere, C. M. et al

in Interactive Cardiovascular and Thoracic Surgery (2003), 2(3), 389-94

To improve our understanding of myxomatous degeneration of the valvar tissue as seen in mitral valve prolapse, we have compared the biosynthetic phenotype of the connective tissue cells in myxomatous ... [more ▼]

To improve our understanding of myxomatous degeneration of the valvar tissue as seen in mitral valve prolapse, we have compared the biosynthetic phenotype of the connective tissue cells in myxomatous segments (n=4) resected during surgery with that of homologous segments of normal valves (n=4) harvested in age-matched organ donors. The steady-state level of mRNA for selected extracellular matrix macromolecules and metalloproteinases was assessed by quantitative (internal standard controlled) reverse transcriptase-polymerase chain reaction (RT-PCR). Among the investigated gene products, the decorin mRNA expression was significantly increased in degenerative valve compared with normal tissue (211+/-48 vs. 100+/-70, p<0.02). The level of fibrillin 2 also tended to be increased (194+/-88 vs. 100+/-81, p=0.08). These results suggest that myxomatous valvar tissue is characterized by an overexpression of mRNA for decorin. Owing to the role of this small leucine-rich proteoglycan in the regulation of fibril assembly and stability, this alteration may account for or is a result of a defective organization of the collagen and elastic fibers in this disease and contribute to the intrinsic distensibility and fragility of the myxomatous tissue. [less ▲]

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See detailComparative study of different lipases acting on milk fat globule membrane monolayers.
Danthine, Sabine ULg; Blecker, Christophe ULg; Deroanne, Claude

Poster (2003, September)

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