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See detailDeficiency of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) impairs nutritionally induced obesity in mice.
Lijnen, Roger; Demeulemeester, Diego; Van Hoef, B. et al

in Thrombosis and Haemostasis (2003), 89(2), 249-255

Tissue inhibitor of matrix metalloproteinase-1 deficient (TIMP-1(-/-)) mice and wild-type (TIMP-1(+/+)) controls were kept on a standard (SFD) or a high fat diet (HFD) for 15 weeks. At the time of ... [more ▼]

Tissue inhibitor of matrix metalloproteinase-1 deficient (TIMP-1(-/-)) mice and wild-type (TIMP-1(+/+)) controls were kept on a standard (SFD) or a high fat diet (HFD) for 15 weeks. At the time of sacrifice, TIMP-1(-/-) mice on HFD had a significantly lower body weight (29 +/- 1.5 versus 41 +/- 1.8 g, p <0.005), and significantly less subcutaneous (0.81 +/- 0.19 versus 1.78 +/- 0.21 g, p <0.05) and gonadal (0.87 +/- 0.17 versus 1.85 +/- 0.18 g, p <0.005) fat mass. These differences were much less pronounced for mice on SFD. On HFD but not on SFD, adipocyte diameters were significantly lower in the adipose tissue of TIMP-1(-/-) mice. Plasma leptin levels in TIMP-1(-/-) mice on HFD were significantly lower as compared to TIMP-1(+/-) mice, and strongly correlated with adipose tissue mass for both genotypes. Staining with an endothelial cell specific lectin revealed a significantly higher blood vessel density, larger stained area and vessel size in adipose tissue of TIMP-1(-/-) mice on HFD. This difference disappeared after normalization to the adipocyte number, suggesting that it does not represent a true enhancement of angiogenesis. Thus, in a murine model of nutritionally induced obesity, TIMP-1 promotes adipose tissue development. [less ▲]

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See detailA new proposal of a simple model for the lateral-torsional buckling of unrestrained steel I-beams in case of fire: experimental and numerical validation
Vila Real, Paolo; Piloto, Paolo; Franssen, Jean-Marc ULg

in Journal of Constructional Steel Research (2003), 59(2), 179-199

The behaviour of Steel I-Beams exhibiting lateral-torsional buckling at elevated temperature has been studied by means of experimental and numerical analysis. The authors in an earlier paper have ... [more ▼]

The behaviour of Steel I-Beams exhibiting lateral-torsional buckling at elevated temperature has been studied by means of experimental and numerical analysis. The authors in an earlier paper have presented an analytical formula for the buckling resistance moment in the fire design situation. This new proposal, different from the actual proposal of the Eurocode 3 Part 1.2 has been validated in this work by comparison with the results from a set of 120 experimental and numerical tests performed on IPE 100 beams, submitted to temperatures varying from room temperature to 600 degreesC. The numerical simulations have been based on the measured geometrical dimensions of the cross-sections, the longitudinal imperfections, i.e. the out of straightness of the beams, the residual stresses and the yield strength. The Eurocode simple model promotes ultimate loads that depend mainly on the non-dimensional slenderness of the beams. The analytical results provided by the Eurocode 3, for a certain range of the slenderness, appear to be unsafe when compared with the numerical and experimental results. It is shown that the new proposal is safer than the Eurocode 3 formulas. (C) 2002 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailFamily size and optimal income taxation
Cremer, Helmuth; Dellis, Arnaud; Pestieau, Pierre ULg

in Journal of Population Economics (2003), 16(1), 37-54

This paper studies the role of family size in the design of optimal income taxation. We consider a second best setting where the government observes the number of children and the income of the parents ... [more ▼]

This paper studies the role of family size in the design of optimal income taxation. We consider a second best setting where the government observes the number of children and the income of the parents but not their productivity. With a linear tax schedule the marginal tax rate is shown to decrease with the number of children, while the relationship between the demogrant and family size appears to be ambiguous. With two ability levels, optimal non-linear income tax implies zero marginal tax rates for the higher ability parents; low ability parents have positive marginal tax rates that decrease with family size. [less ▲]

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See detailLine profile variability in the spectra of Oef stars. I. BD + 60deg 2522
Rauw, Grégor ULg; De Becker, Michaël ULg; Vreux, Jean-Marie ULg

in Astronomy and Astrophysics (2003), 399

We report the analysis of a long term observing campaign designed to monitor the spectroscopic variability of the Oef star BD +60deg 2522. We find that the double-peaked He {II} lambda 4686 emission line ... [more ▼]

We report the analysis of a long term observing campaign designed to monitor the spectroscopic variability of the Oef star BD +60deg 2522. We find that the double-peaked He {II} lambda 4686 emission line undergoes strong profile variability on time scales of 2-3 day. However, the time scale as well as the pattern of these variations turn out to be epoch dependent and the phenomenon is thus most likely not ruled by a single stable clock. On the other hand, the absorption lines in the spectrum of BD +60deg 2522 display line profile variability on time scales of a few hours that might be related to non-radial pulsations. We tentatively propose that the beating of several non-radial pulsation modes triggers transient large-scale density perturbations in a confined stellar wind that produce the 2-3 day time scale variability. [less ▲]

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See detailClient, Mon Cher Client !
Van Caillie, Didier ULg

Article for general public (2003)

This chronicle insists on the importance of the Customer Relationship Management in modern firms, even in the smallest ones, and insists on the ability of the firm to adequately value its relation with ... [more ▼]

This chronicle insists on the importance of the Customer Relationship Management in modern firms, even in the smallest ones, and insists on the ability of the firm to adequately value its relation with its main clients. [less ▲]

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See detailGuide Technique Parasismique Belge pour Maisons Individuelles
Plumier, André ULg; Doneux, Catherine; Caporaletti, Valeria et al

Book published by Département M&S de l'Université de Liège (2003)

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See detailLire ou ne pas lire : état de la question
Baye, Ariane ULg; Lafontaine, Dominique ULg; Vanhulle, Sabine

in Cahiers du Centre de Lecture publique de la Communauté française (2003), 4

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See detailTraitement hormonal apres cancer du sein. Oui ... ou non?
Foidart, Jean-Michel ULg; Desreux, Joëlle ULg; Lifrange, Eric ULg et al

in Revue Médicale de Liège (2003), 58(2), 77-82

Clinical and experimental studies indicate that combined unique conjugated estrogens and medroxyprogesterone acetate moderately increase the risk of breast cancer in postmenopausal women. Classically ... [more ▼]

Clinical and experimental studies indicate that combined unique conjugated estrogens and medroxyprogesterone acetate moderately increase the risk of breast cancer in postmenopausal women. Classically, hormone replacement therapy is contra-indicated in women with a past history of breast cancer due to the fear of recurrence. However, these postmenopausal patients complain about hot flushes and adjuvant hormonal therapies (such as aromatase inhibitors, SERMs and Tamoxifen...) aggravate their symptoms. Observational studies and their meta-analyses do not show a deleterious effect but rather a beneficial impact of hormone replacement therapy among women with a past history of breast cancer. We summarise all these studies and their biological, clinical and epidemiological interpretations. We conclude that short term hormone replacement therapy is safe among those women requesting a replacement therapy after complete information. It is however advisable to conclude definitely only when prospective randomised trials with estradiol or tibolone (a promising alternative) will be available. Such ongoing studies will allow to conclude definitely the possible benefits and risks of hormone replacement therapy among patients with a past history of breast cancer. [less ▲]

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See detailMorphological study of magnesium hydroxide nanoparticles precipitated in dilute aqueous solution
Henrist, Catherine ULg; Mathieu, J. P.; Vogels, C. et al

in Journal of Crystal Growth (2003), 249(1-2), 321-330

Among other applications, magnesium hydroxide is commonly used as a flame-retardant filler in composite materials, as well as a precursor for magnesium oxide refractory ceramic. The microstructure of the ... [more ▼]

Among other applications, magnesium hydroxide is commonly used as a flame-retardant filler in composite materials, as well as a precursor for magnesium oxide refractory ceramic. The microstructure of the powder is of prime importance in both technical applications. The influence of synthesis parameters on the morphological characteristics of magnesium hydroxide nanoparticles precipitated in dilute aqueous medium was studied. Several parameters were envisaged such as chemical nature of the base precipitant, type of counter-ion, temperature and hydrothermal treatment. Special attention was given to the obtaining of platelet-shaped, nanometric and de-agglomerated powders. The powders were characterized in terms of particle size distribution, crystal habits, morphology and ability to be redispersed in water. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption and laser diffusion analyses were used for this purpose. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailRegulation of training system for adults in educational technology
Denis, Brigitte ULg; Piette, Sylvie-Anne

in Stacey, E.; Davies, E. (Eds.) Quality education @ a distance (2003, February)

This paper reports the characteristics of a post graduate diploma on educational technologies based on a combination of face-to-face and distance activities and assesses its quality. We first define the ... [more ▼]

This paper reports the characteristics of a post graduate diploma on educational technologies based on a combination of face-to-face and distance activities and assesses its quality. We first define the bases of the training program and present several tools (logbook, portfolio and questionnaires) which have been used to evaluate and regulate both training and individual learning process. Our observations indicate an increase and better regulation of the quality of the educational and learning processes. On the basis of the results we achieved, we propose that our original design could be extended to similar adult training programs. The way this innovative system is integrated in the universities shows an evolution due to its success that implies a certain kind of return on investment due to the demand of such kinds of device. [less ▲]

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See detailLa notion de réseau en sciences sociales
Claisse, Frédéric ULg

Scientific conference (2003, January 22)

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See detailClonage, caractérisation et étude de la régulation transcriptionnelle du gène Aox1 encodant l'oxydase alternative chez Chlamydomonas reinhardtii
Baurain, Denis ULg

Doctoral thesis (2003)

Au sein de la membrane interne des mitochondries, quatre complexes multiprotéiques sont impliqués dans le transfert des électrons depuis les équivalents réducteurs jusqu'à l'oxygène moléculaire. L'énergie ... [more ▼]

Au sein de la membrane interne des mitochondries, quatre complexes multiprotéiques sont impliqués dans le transfert des électrons depuis les équivalents réducteurs jusqu'à l'oxygène moléculaire. L'énergie associée à ce transport au travers des complexes I, III et IV est couplée à la synthèse d'ATP par l'intermédiaire d'un gradient de protons. Chez les plantes supérieures, de nombreux champignons et quelques protistes, une seconde voie de transfert diverge de la voie principale au niveau du pool d'ubiquinone, celui-ci étant alors oxydé directement par l'oxygène moléculaire. Lorsque les électrons empruntent cette voie alternative, deux sites d'éjection de protons sont court-circuités et l'énergie produite est dissipée sous forme de chaleur. Cette réaction est catalysée par une enzyme unique, l'oxydase alternative (AOX), souvent encodée par une petite famille multigénique chez les plantes supérieures. Une activité accrue de la voie alternative est observée suite à divers stimuli développementaux et environnementaux, en particulier en conditions de stress. Cette augmentation d'activité résulte d'une activation transcriptionnelle du gène Aox et/ou de modifications post-traductionnelles de la protéine mature. L'AOX de l'algue verte unicellulaire Chlamydomonas reinhardtii est encodée par deux gènes différents, Aox1 et Aox2, le premier étant beaucoup plus transcrit que le second. Les cDNAs Aox1 et Aox2, de même que la séquence génomique Aox2, ont été isolés et caractérisés dans notre laboratoire. Dans un premier temps, nous avons entrepris le clonage et la caractérisation de la séquence génomique Aox1, ce qui nous a permis de comparer sa structure avec celle de son homologue Aox2. Ensuite, afin d'étudier sa régulation transcriptionnelle, nous avons fusionné un segment de 1,4 kb contenant la région promotrice Aox1 à la région codante du gène (Ars) de l'arylsulfatase et mesuré les activités ARS dans des transformants porteurs de la construction chimérique. Nous avons ainsi montré que le promoteur Aox1 est insensible à la plupart des inducteurs classiques de l'AOX, parmi lesquels des agents de stress, des inhibiteurs respiratoires et des métabolites. En revanche, l'expression du gène Aox1 répond à la nature de la source d'azote, sa transcription étant réprimée par l'ammonium et stimulée par le nitrate. De plus, en milieu contenant du nitrate, l'inactivation de la nitrate réductase (première enzyme de la voie d'assimilation du nitrate) conduit à une expression du gène Aox1 encore plus importante. Nous avons en outre observé que cette stimulation par le nitrate se répercute aux niveaux protéique et respiratoire. Une étude de délétion de la région promotrice Aox1 indique qu'un segment court (de −253 à +59 par rapport à l'origine de transcription) est suffisant pour assurer la transcription et la régulation du gène, mais que son expression maximale requiert également des éléments distaux. Aucun motif nucléotidique susceptible d'intervenir dans l'expression du gène Aox1 n'a été identifié à l'issue d'une analyse bioinformatique du promoteur. L'effet de la nature de la source d'azote sur l'expression de l'AOX est interprété sous l'angle d'une optimisation de la synthèse d'ATP mitochondrial sans modification de l'activité respiratoire, en relation avec un possible accroissement de la production d'ATP photosynthétique lorsque le nitrate est utilisé comme source d'azote. [less ▲]

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See detailCalcification and organic production of coccolithophorids Emiliania huxleyi under different atmospheric pCO2 in a mesocosm experiment
Delille, Bruno ULg; Harlay, Jérôme ULg; Chou, Lei et al

Poster (2003, January 07)

The response of primary production and calcification of the coccolithophorid Emiliania huxleyi to different partial pressures of CO2 (p CO2) have been investigated during a mesocosm bloom experiment in a ... [more ▼]

The response of primary production and calcification of the coccolithophorid Emiliania huxleyi to different partial pressures of CO2 (p CO2) have been investigated during a mesocosm bloom experiment in a Norwegian fjord. Glacial, present and next century atmospheric p CO2 conditions (respectively 180, 370 and 700 ppmV) have been simulated above the surface of large sea-water enclosures. If production of organic matter remains constant under elevated p CO2, the production of inorganic carbon appears to be affected in two ways. First, the beginning of calcification is delayed. Second, the production rate of inorganic carbon appears to be lowered by 40% in the future conditions, decreasing subsequently the calcification/photosynthesis ratio from 1 to 0.6. During the experiment a strong viral growth have been experienced, which have seriously depressed calcification as well. We propose the threshold of 5.10 6 cell/ml for E huxleyi virus abundance above which the production and calcification of the population of E. huxleyi are severely affected. [less ▲]

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See detailAssessment of the importance of the carbonate pump in surface waters of the Bay of Biscay
Harlay, Jérôme ULg; Chou, Lei; Dedonder, Virginie et al

Poster (2003, January 07)

Marine carbon research in the past decade has been mainly devoted to the understanding and quantification of processes controlling the fluxes of organic matter in the ocean. Little attention has been paid ... [more ▼]

Marine carbon research in the past decade has been mainly devoted to the understanding and quantification of processes controlling the fluxes of organic matter in the ocean. Little attention has been paid until now to the particulate inorganic carbon whose net fluxes to the sediments are comparable to those of the organic matter. There remains still a large uncertainty in the production and the fate of biogenic calcium carbonate in the oceanic carbon cycle. In the framework of the Belgian global change programme, we have developed a project devoted to the study of the inorganic carbon cycle in the Bay of Biscay where coccolithophorid blooms occur frequently. The study focuses on processes associated with the oceanic production and dissolution of calcium carbonate, by combining field investigations, laboratory experiments and modelling efforts. The rate of primary production and of calcification by phytoplankton is evaluated by 14C incubation experiments during a coccolithophorid bloom-forming period in the area of investigation. The relative production of organic matter and calcium carbonate in the photic zone along a transect from the continental shelf across the slope to deep waters will be presented. A tentative mass balance of the carbon fluxes for this area will be constructed. These preliminary results confirm the importance that the calcium carbonate pump may play in open ocean. [less ▲]

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See detailDe novo backbone and sequence design of an idealized alpha/beta-barrel protein: Evidence of stable tertiary structure
Offredi, Fabrice; Dubail, Fabien; Kischel, Philippe ULg et al

in Journal of Molecular Biology (2003), 325(1), 163-174

We have designed, synthesized, and characterized a 216 amino acid residue sequence encoding a putative idealized alpha/beta-barrel protein. The design was elaborated in two steps. First, the idealized ... [more ▼]

We have designed, synthesized, and characterized a 216 amino acid residue sequence encoding a putative idealized alpha/beta-barrel protein. The design was elaborated in two steps. First, the idealized backbone was defined with geometric parameters representing our target fold: a central eight parallel-stranded beta-sheet surrounded by eight parallel alpha-helices, connected together with short structural turns on both sides of the barrel. An automated sequence selection algorithm, based on the dead-end elimination theorem, was used to find the optimal amino acid sequence fitting the target structure. A synthetic gene coding for the designed sequence was constructed and the recombinant artificial protein was expressed in bacteria, purified and characterized. Far-UV CD spectra with prominent bands at 222nm and 208nm revealed the presence of alpha-helix secondary structures (50%) in fairly good agreement with the model. A pronounced absorption band in the near-UV CD region, arising from immobilized aromatic side-chains, showed that the artificial protein is folded in solution. Chemical unfolding monitored by tryptophan fluorescence revealed a conformational stability (DeltaG(H2O)) of 35kJ/mol. Thermal unfolding monitored by near-UV CD revealed a cooperative transition with an apparent T(m) of 65 degrees C. Moreover, the artificial protein did not exhibit any affinity for the hydrophobic fluorescent probe 1-anilinonaphthalene-8-sulfonic acid (ANS), providing additional evidence that the artificial barrel is not in the molten globule state, contrary to previously designed artificial alpha/beta-barrels. Finally, 1H NMR spectra of the folded and unfolded proteins provided evidence for specific interactions in the folded protein. Taken together, the results indicate that the de novo designed alpha/beta-barrel protein adopts a stable three-dimensional structure in solution. These encouraging results show that de novo design of an idealized protein structure of more than 200 amino acid residues is now possible, from construction of a particular backbone conformation to determination of an amino acid sequence with an automated sequence selection algorithm. [less ▲]

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See detailDifferential expression of plasminogen activator inhibitor-1, tumor necrosis factor-alpha, TNF-alpha converting enzyme and ADAMTS family members in murine fat territories
Vörös, Gabor; Maquoi, Erik ULg; Collen, Désiré et al

in Biochimica et Biophysica Acta-Gene Structure and Expression (2003), 1625(1), 36-42

ur objective was to investigate expression of A disintegrin and metalloproteinase (ADAM) and ADAM proteins with a thrombospondin (TS) motif (ADAMTS) family members in adipose tissue of lean and obese mice ... [more ▼]

ur objective was to investigate expression of A disintegrin and metalloproteinase (ADAM) and ADAM proteins with a thrombospondin (TS) motif (ADAMTS) family members in adipose tissue of lean and obese mice. Five-week-old male mice were kept on standard chow (SFD) or on high fat diet (HFD) for 15 weeks, and subcutaneous (SC) and gonadal (GON) adipose tissue, as well as mature adipocytes and stromal–vascular (S–V) cells were harvested. mRNA levels of plasminogen activator inhibitor-1 (PAI-1), tumor necrosis factor-α (TNF-α), ADAM-17 (TACE or TNF-α converting enzyme), ADAMTS-1 and ADAMTS-8 were quantified in isolated adipose tissues and cell fractions, and during differentiation of murine preadipocytes. The HFD resulted in a significantly enhanced weight of isolated SC and GON fat pads, and in enhanced blood levels of glucose, cholesterol and PAI-1. ADAM-17, TNF-α, PAI-1, ADAMTS-1 and ADAMTS-8 mRNA were detected in both SC and GON adipose tissue of lean mice (SFD). In SC adipose tissue of obese mice (HFD), the expression of ADAM-17 and PAI-1 was enhanced and that of ADAMTS-1 reduced, whereas in GON adipose tissue expression of TNF-α was enhanced and that of ADAMTS-8 reduced. In lean and obese mice, expression of ADAM-17, ADAMTS-1 and ADAMTS-8 was higher in the S–V cell fraction than in mature adipocytes. During differentiation of murine 3T3-F442A preadipocytes, expression of ADAM-17 and ADAMTS-1 remained virtually unaltered, whereas that of ADAMTS-8 decreased as adipocytes matured. Several ADAM and ADAMTS family members are expressed in adipose tissue and during differentiation of preadipocytes. Modulation of their expression upon development of obesity is adipose tissue-dependent. [less ▲]

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See detailSimulation of metal forming processes : Numerical aspects of contact and friction
Boman, Romain ULg

Scientific conference (2003, January)

During this presentation, two numerical methods for managing contact in large stresses/strains problems are described: the Lagrange Multipliers method (available in Cast3M - FE code used in LaCaN) and the ... [more ▼]

During this presentation, two numerical methods for managing contact in large stresses/strains problems are described: the Lagrange Multipliers method (available in Cast3M - FE code used in LaCaN) and the penalty method (available in Metafor - FE code used at LTAS-MCT - University of Liège). Contact algorithms can be divided into three steps. The first one - the contact search - is purely geometric and answers the question: which nodes are currently in contact. Main problems and their solutions are discussed. The computation of the normal force is the second step. Non-penetration conditions are applied on the contact nodes. Finally, during the third step, a tangent force due to friction is applied when the nodes are sticking or sliding. Methods are compared in details in the case of metal forming processes. The penalty method seems to be more efficient when a large number of contact nodes are involved during the simulation. The system to be solved is smaller, the convergence is faster and curved analytical surfaces can be easily used for the tools. However, a good penalty coefficient can sometimes be hard to find. As a conclusion, numerical examples coming from Metafor are presented including skin-pass simulation, hydroforming of a tube and blade loss in a aeronautic engine. [less ▲]

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See detailCréation d'entreprise et utilisation de l'informatique
Robert, Jocelyne ULg

in Quel genre pour l'égalité? (2003)

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