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See detailEvidence of a limited contribution of feto-maternal interactions to trophoblast differentiation along the invasive pathway
Goffin, Frédéric ULg; Munaut, Carine ULg; Malassine, A. et al

in Tissue Antigens (2003), 62(2), 104-116

Trophoblast differentiation is a key event in human placental development. During extravillous trophoblast (EVT) differentiation, stem cells from the anchoring villi detach from their basement membrane ... [more ▼]

Trophoblast differentiation is a key event in human placental development. During extravillous trophoblast (EVT) differentiation, stem cells from the anchoring villi detach from their basement membrane and proliferate to form aggregates called trophoblast cell columns (TCCs). They subsequently invade the decidua and differentiate into interstitial and endovascular trophoblasts. The influence of the decidua on EVT differentiation is controversial. We therefore compared the pattern of trophoblast differentiation marker expression in viable intrauterine and tubal pregnancies, as decidual cell markers (prolactin [PRL] and insulin-like growth factor binding Protein-1 [IGFBP1]) were only expressed in endometrial implantation sites. Extravillous trophoblast differentiation in anchoring villi from uterine and ectopic pregnancies exhibited a comparable phenotypical switch: alpha6 integrin subunit, E-cadherin, EGF receptor, Ki 67 and connexin 40 were localized in the proximal part of the TCC, while alpha5beta1 and alpha1 integrins, c-erb B2, hPL and HLA-G were expressed by invasive cytotrophoblasts. The cyclin-dependent kinase inhibitors p16 and p57 were mainly detected in invasive cytotrophoblasts some distance from the columns. However, the TCC was markedly longer in tubal pregnancy than in intrauterine pregnancy. These findings suggest that the decidua is not necessary to trigger EVT invasion, but that it is likely to limit the extent of the TCC and to accelerate the onset of EVT migration. [less ▲]

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See detailReconstructing neutrino properties from collider experiments in a Higgs triplet neutrino mass model
Aristizabal Sierra, Diego ULg; Hirsch, M.; Valle, J. W. F. et al

in Physical Review. D : Particles and Fields (2003), 68

We extend the minimal supersymmetric standard model with bilinear R-parity violation to include a pair of Higgs triplet superfields. The neutral components of the Higgs triplets develop small vacuum ... [more ▼]

We extend the minimal supersymmetric standard model with bilinear R-parity violation to include a pair of Higgs triplet superfields. The neutral components of the Higgs triplets develop small vacuum expectation values (VEVs) quadratic in the bilinear R-parity breaking parameters. In this scheme the atmospheric neutrino mass scale arises from bilinear R-parity breaking while for reasonable values of parameters the solar neutrino mass scale is generated from the small Higgs triplet VEVs. We calculate neutrino masses and mixing angles in this model and show how the model can be tested at future colliders. The branching ratios of the doubly charged triplet decays are related to the solar neutrino angle via a simple formula. [less ▲]

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See detailComprehensive Analysis of PBDEs, PCDD/Fs and PCBs
PIRARD, Catherine ULg; De Pauw, Edwin ULg; Focant, Jean-François ULg

Conference (2003, August)

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See detailRecent progress in ring-opening of ε-caprolactone and derivatives
Lecomte, Philippe ULg; Jérôme, Robert ULg

Conference (2003, July 02)

This oral communication was presented by Philippe Lecomte

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See detailA Hare and Hound in a BAG: Asteroseismology of Beta Cephei stars
Thoul, Anne ULg; Ausseloos, M.; Barban, C. et al

in Communications in Asteroseismology (2003), 143

Several members of the COROT Seismology Working Group (SWG) have performed several ``hare-and-hound'' exercises to prepare the data exploitation of the mission in the past few years. These exercises ... [more ▼]

Several members of the COROT Seismology Working Group (SWG) have performed several ``hare-and-hound'' exercises to prepare the data exploitation of the mission in the past few years. These exercises consist in reproducing a theoretical model on the basis of a light curve obtained from a frequency spectrum computed from an ``unknown'' theoretical model of a solar-like or a Delta Scuti star. Members of the BAG (Belgian Asteroseismology Group) have now shown that such an exercise in the mass range of Beta Cephei stars is extremely convincing, making these stars excellent targets for asteroseismology space missions. [less ▲]

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See detailA quadruply imaged quasar with an optical Einstein ring candidate: 1RXS J113155.4-123155
Sluse, D.; Surdej, Jean ULg; Claeskens, Jean-François ULg et al

in Astronomy and Astrophysics (2003), 406(Letters), 43-46

We report the discovery of a new quadruply imaged quasar surrounded by an optical Einstein ring candidate. Spectra of the different components of 1RXS J113155.4-123155 reveal a source at z= 0.658. Up to ... [more ▼]

We report the discovery of a new quadruply imaged quasar surrounded by an optical Einstein ring candidate. Spectra of the different components of 1RXS J113155.4-123155 reveal a source at z= 0.658. Up to now, this object is the closest known gravitationally lensed quasar. The lensing galaxy is clearly detected. Its redshift is measured to be z= 0.295. Additionally, the total V magnitude of the system has varied by 0.3 mag between two epochs separated by 33 weeks. The measured relative astrometry of the lensed images is best fitted with an SIS model plus shear. This modeling suggests very high magnification of the source (up to 50 for the total magnification) and predicts flux ratios between the lensed images significantly different from what is actually observed. This suggests that the lensed images may be affected by a combination of micro or milli-lensing and dust extinction effects. Based on data collected at the European Southern Observatory, La Silla, Chile. [less ▲]

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See detailSeismic modelling of the beta Cep star EN (16) Lacertae
Thoul, Anne ULg; Aerts, C.; Dupret, Marc-Antoine ULg et al

in Astronomy and Astrophysics (2003), 406(1), 287-292

We perform seismic modelling of the massive beta Cep star EN Lacertae. The starting point of our analysis is the spectroscopic mode identification recently performed. To this, we add a new updated ... [more ▼]

We perform seismic modelling of the massive beta Cep star EN Lacertae. The starting point of our analysis is the spectroscopic mode identification recently performed. To this, we add a new updated photometric mode identification based upon a non-adiabatic description of the eigenfunctions in the outer atmosphere. Both mode identifications agree and this allows us to fine-tune the stellar parameters of EN Lacertae with unprecedented precision. This is done by producing a huge amount of stellar models with different parameters and selecting those that fulfill the frequency values and the mode identification. Our study is the first one of its kind in which a reconcilation between observed pulsational characteristics and theoretical models can be achieved at a level that allows accurate determination of the basic stellar parameters of a massive oscillator. We derive a mass of M=9.62+/- 0.11 M[SUB]sun[/SUB] and an age of 15.7 million years if we assume that convective overshooting does not occur. [less ▲]

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See detailRegulation of membrane-type 1 matrix metalloproteinase activity by vacuolar H+-ATPases
Maquoi, Erik ULg; Peyrollier, K.; Noël, Agnès ULg et al

in Biochemical Journal (2003), 373(Pt 1), 19-24

Membrane-type I matrix metalloprotemase (MT1-MMP) is a key enzyme in normal development and malignant processes. The regulation of MT1-MMP activity on the cell surface is a complex process involving ... [more ▼]

Membrane-type I matrix metalloprotemase (MT1-MMP) is a key enzyme in normal development and malignant processes. The regulation of MT1-MMP activity on the cell surface is a complex process involving autocatalytic processing, tissue inhibitor of MMPs (TIMP) binding and constitutive internalization. However, the fate of internalized MT1-MMP is not known. Acidification of intracellular vacuolar compartments is essential for membrane trafficking, protein sorting and degradation. This acidification is controlled by vacuolar H+-ATPases, which can be selectively inhibited by bafilomycin-A(1). Here, we treated human tumour cell lines expressing MT1-MMP with bafilomycin-A(1), and analysed its effects on MT1-MMP activity, internalization and processing. We show that the activity of MT1-MMP on the cell surface is constitutively down-regulated through a vacuolar HI-ATPase-dependent degradation process. Blockade of this degradation caused the accumulation of TIMP-free active MT1-MMP molecules on the cell surface, although internalization was not affected. As a consequence of this impaired degradation, pro-MMP-2 activation was strongly enhanced. This study demonstrates that the catalytic activity of MT1-MMP on the cell surface is regulated through a vacuolar H+-ATPase-dependent degradation process. [less ▲]

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See detail2-oxepane-1,5-dione: a precursor of a novel class of versatile semicrystalline biodegradable (co)-polyesters
Lecomte, Philippe ULg; Latere Dwan'Isa, Jean-Pierre; Dubois, Philippe et al

Poster (2003, July 01)

2-oxepane-1,5-dione (OPD) was synthesized by Baeyer-Villiger oxidation of 1,4-cyclohexanedione and ring-opening polymerized by 1-phenyl-2-propanol / tin octoate with formation of a semicrystalline ... [more ▼]

2-oxepane-1,5-dione (OPD) was synthesized by Baeyer-Villiger oxidation of 1,4-cyclohexanedione and ring-opening polymerized by 1-phenyl-2-propanol / tin octoate with formation of a semicrystalline polyester of high melting temperature (Tm: 147°C). A crystallographic study showed that the polyester is orthorombic in the P212121 space with two molecules extended along the c-axis as is the case for poly(ε-caprolactone) (PCL). Dibutyltin dimethoxide and 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP) proved to be efficient initiators for the random copolymerization of ε-caprolactone (εCL) and OPD. Random distribution of the comonomer units was confirmed by DSC, 1H and 13C NMR analyses. A single Tm was observed, which varies regularly and monotonically with the OPD content as result of a cocrystallisation phenomenon. The single glass transition temperature (Tg) obeys the Fox equation. It is noteworthy that a copolymer containing 30 mol % OPD exhibits a Tm of 90°C. It is stable up to 140°C under nitrogen for one hour, such that processing by extrusion is quite possible. The OPD decomposition is maximum at 223°C for a heating rate of 10°C/min. The mechanism of thermal degradation was investigated and cleared up. The ketone increases the copolymer hydrophilicity and thus sensitivity to hydrolysis. The mechanical properties are quite reminiscent of PCL of comparable molecular weight. Quite interestingly, OPD imparts sensitivity to photo-cross-linking to this novel class of materials. [less ▲]

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See detailBulletin agrométéorologique - Juin 2003
Tychon, Bernard ULg; Ozer, P.; Eerens, H. et al

in Bulletin Agrométéorologique (2003)

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See detailLa modélisation de la dispersion atmosphérique. Cas particulier des odeurs.
Nicolas, Jacques ULg; Craffe, Flavien

Report (2003)

The report was written in the frame of a general project concerning the "plan of air in Wallonia", aiming at inventory the policies, standards and measurement methods concerning the air quality. The ... [more ▼]

The report was written in the frame of a general project concerning the "plan of air in Wallonia", aiming at inventory the policies, standards and measurement methods concerning the air quality. The present report refers to the atmospheric dispersion models and their particular use to simulate the odour plumes. [less ▲]

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See detailÀ quel âge est-on prêt à voter ? La participation des jeunes à la vie collective
Hudon, Raymond; Fournier, Bernard ULg

in Perspectives électorales/Electoral Insight (2003), 5(2), 36-41

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See detailHow Old Is Old Enough to Vote. Youth Participation in Society
Hudon, Raymond; Fournier, Bernard ULg

in Perspectives électorales/Electoral Insight (2003), 5(2), 38-43

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See detailHybrid Acceleration using Real Vector Automata
Boigelot, Bernard ULg; Herbreteau, Frédéric; Jodogne, Sébastien ULg

in Lecture Notes in Computer Science (2003, July), 2725

This paper addresses the problem of computing an exact and effective representation of the set of reachable configurations of a linear hybrid automaton. Our solution is based on accelerating the state ... [more ▼]

This paper addresses the problem of computing an exact and effective representation of the set of reachable configurations of a linear hybrid automaton. Our solution is based on accelerating the state-space exploration by computing symbolically the repeated effect of control cycles. The computed sets of configurations are represented by Real Vector Automata (RVA), the expressive power of which is beyond that of the first-order additive theory of reals and integers. This approach makes it possible to compute in finite time sets of configurations that cannot be expressed as finite unions of convex sets. The main technical contributions of the paper consist in a powerful sufficient criterion for checking whether a hybrid transformation (i.e., with both discrete and continuous features) can be accelerated, as well as an algorithm for applying such an accelerated transformation on RVA. Our results have been implemented and successfully applied to several case studies, including the well-known leaking gas burner, and a simple communication protocol with timers. [less ▲]

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See detailSocial insurance competition between Bismarck and Beveridge
Cremer, H.; Pestieau, Pierre ULg

in Journal of Urban Economics (2003), 54(1), 181-196

Social insurance schemes differ according to the relationship between contributions and benefits. Bismarckian systems provide earnings-related benefits, while Beveridgean systems offer flat payments. The ... [more ▼]

Social insurance schemes differ according to the relationship between contributions and benefits. Bismarckian systems provide earnings-related benefits, while Beveridgean systems offer flat payments. The conventional wisdom is that with factor mobility poor people have incentives to move towards Beveridgean countries. Consequently, Beveridgean regimes would not be sustainable under economic integration. This paper studies the validity of such a conjecture within a simple model. It is shown that mobility does have a significant impact on social protection. However, the equilibrium patterns that can emerge are more complex and diversified than the initial conjecture suggests. In some cases, the equilibrium may even imply that all the poor move to the Bismarckian country. (C) 2003 Elsevier Inc. All rights reserved. [less ▲]

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