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See detailWhy does the red algal plastid lineage lack plastocyanin?
Baurain, Denis ULg; Demoulin, Vincent ULg

Conference (2005, February 03)

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See detailL'astronomie dans le monde
Manfroid, Jean ULg

Article for general public (2005)

Ultrasons solaires, GMT, Caméra infrarouge géante, Mars, Titan et Dioné, Japet, les anneaux, Mimas, Huygens sur Titan, découverte d'un nouveau monde, Swift débute, pulsar 3C58, Jeunes galaxies, 2004 MN4 ... [more ▼]

Ultrasons solaires, GMT, Caméra infrarouge géante, Mars, Titan et Dioné, Japet, les anneaux, Mimas, Huygens sur Titan, découverte d'un nouveau monde, Swift débute, pulsar 3C58, Jeunes galaxies, 2004 MN4 near miss, volcans martiens, Et de cinq Champs magnétiques et nébuleuses planétaires, [less ▲]

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See detailOctreotide (long-acting release formulation) treatment in patients with graves' orbitopathy: clinical results of a four-month, randomized, placebo-controlled, double-blind study.
Wemeau, J. L.; Caron, P.; Beckers, Albert ULg et al

in Journal of Clinical Endocrinology and Metabolism (2005), 90(2), 841-848

There are few effective, safe modalities for the management of Graves' ophthalmopathy (GO), a cell-mediated immune comorbidity of thyroid disease. Somatostatin analogs inhibit lymphocyte proliferation and ... [more ▼]

There are few effective, safe modalities for the management of Graves' ophthalmopathy (GO), a cell-mediated immune comorbidity of thyroid disease. Somatostatin analogs inhibit lymphocyte proliferation and activation, and accumulate in the orbital tissue of patients with GO. A double-blind, placebo-controlled study of a long-acting somatostatin analog [16 wk of long-acting release formulation of octreotide (octreotide-LAR)] was conducted in 51 patients with mild active GO with the aim of preventing deterioration and precluding the need for more aggressive therapeutic modalities, such as glucocorticoids or radiotherapy. No treatment effect was observed for the primary end point (a composite parameter defining the outcome as either success or failure on the basis of changes in class/grade of the severity index and Clinical Activity Scale of GO). The Clinical Activity Scale score was reduced for patients treated with octreotide-LAR, but without any significant difference with respect to patients receiving placebo. However, octreotide-LAR significantly reduced proptosis (as measured by exophthalmometry). This was associated with nonsignificant differences in favor of octreotide-LAR in a series of proptosis-related parameters: class III grade, opening of the upper eyelid, the difference in ocular pressure between primary position and upgaze, and extraocular muscle involvement. By magnetic resonance imaging evaluation the extraocular muscle volumes appeared reduced, but nonsignificantly. No significant correlation between the initial uptake of the somatostatin analog indium-labeled and the response to treatment was observed. One patient in the octreotide-LAR group developed gallstones. In this study, octreotide-LAR did not seem suitable to mitigate activity in mild GO. Surprisingly, it significantly reduced proptosis, one of the most debilitating symptoms of GO. Additional studies are warranted to define the benefit to risk ratio of the somatostatin analogs in this indication. [less ▲]

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See detailGamma-ray attenuation for measuring cryogenic slush mixture density
Carapelle, Alain ULg; Collette, Jean-Pierre ULg

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2005), 229(1), 111-116

Gamma-ray attenuation is used to measure cryogenic mixture density. Parameters are optimized for specific space application. A simple error formula is established. The feasibility of the measurement is ... [more ▼]

Gamma-ray attenuation is used to measure cryogenic mixture density. Parameters are optimized for specific space application. A simple error formula is established. The feasibility of the measurement is demonstrated. An automatic measurement device is built. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailArchitecture de Metafor - code EF orienté objet
Boman, Romain ULg

Scientific conference (2005, February)

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See detailMalaise dans les médias
Durand, Pascal ULg

in Espace de Libertés : Magazine du Centre d'Action Laïque (2005)

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See detailAn empirical Bayesian solution to the source reconstruction problem in EEG
Phillips, Christophe ULg; Mattout Jeremie; Rugg, Michael D et al

in Neuroimage (2005), 24(4), 997-1011

Distributed linear solutions of the EEG source localisation problem are used routinely. In contrast to discrete dipole equivalent models, distributed linear solutions do not assume a fixed number of ... [more ▼]

Distributed linear solutions of the EEG source localisation problem are used routinely. In contrast to discrete dipole equivalent models, distributed linear solutions do not assume a fixed number of active sources and rest on a discretised fully 3D representation of the electrical activity of the brain. The ensuing inverse problem is underdetermined and constraints or priors are required to ensure the uniqueness of the solution. In a Bayesian framework, the conditional expectation of the source distribution, given the data, is attained by carefully balancing the minimisation of the residuals induced by noise and the improbability of the estimates as determined by their priors. This balance is specified by hyperparameters that control the relative importance of fitting and conforming to various constraints. Here we formulate the conventional "Weighted Minimum Norm" (WMN) solution in terms of hierarchical linear models. An "Expectation-Maximisation" (EM) algorithm is used to obtain a "Restricted Maximum Likelihood" (ReML) estimate of the hyperparameters, before estimating the "Maximum a Posteriori" solution itself. This procedure can be considered a generalisation of previous work that encompasses multiple constraints. Our approach was compared with the "classic" WMN and Maximum Smoothness solutions, using a simplified 2D source model with synthetic noisy data. The ReML solution was assessed with four types of source location priors: no priors, accurate priors, inaccurate priors, and both accurate and inaccurate priors. The ReML approach proved useful as: (1) The regularisation (or influence of the a priori source covariance) increased as the noise level increased. (2) The localisation error (LE) was negligible when accurate location priors were used. (3) When accurate and inaccurate location priors were used simultaneously, the solution was not influenced by the inaccurate priors. The ReML solution was then applied to real somatosensory-evoked responses to illustrate the application in an empirical setting. (C) 2004 Elsevier Inc. All rights reserved. [less ▲]

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See detailAbdominal aortic aneurysm due to Brucella melitensis
Quaniers, Janine ULg; DURIEUX, Rodolphe ULg; de Leval, Laurence ULg et al

in Acta Chirurgica Belgica (2005), 105(1), 93-95

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See detailL'image du mois. Quadricuspidie aortique, une cause rare d'insuffisance aortique
RADERMECKER, Marc ULg; Jastrzebska, V.; Hiernaux, M. et al

in Revue Médicale de Liège (2005), 60(2), 75-6

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See detailSimulation of crashworthiness problems with implicit time integration methods for non-linear dynamics
Noels, Ludovic ULg; Stainier, Laurent; Ponthot, Jean-Philippe ULg

Scientific conference (2005, February)

When studying impact problems, time integration of the equations of evolution occurs in the non-linear range. Usually, explicit algorithms are used in such a context. Nevertheless, due to its lack of ... [more ▼]

When studying impact problems, time integration of the equations of evolution occurs in the non-linear range. Usually, explicit algorithms are used in such a context. Nevertheless, due to its lack of stability in the non-linear range, and its limitation in the time step size, an implicit scheme could advantageously be used. The most widely used implicit algorithm is the Newmark algorithm. Nevertheless, with this algorithm used in the non-linear range, the conservation of the energy is no longer satisfied. To avoid divergence due to the numerical instabilities, numerical damping was introduced, leading to the generalized- methods. But these schemes can exhibit instabilities in the non-linear range too. Therefore a new family of integration algorithms for problems in structural dynamics has appeared that satisfies the mechanical laws of conservation (i.e. conservation of linear momentum, angular momentum and total energy) and that remains stable in the non-linear range. The first algorithm verifying these properties was described by Simo and Tarnow. They called this algorithm Energy Momentum Conserving Algorithms or EMCA. It consists in a mid-point scheme with an adequate evaluation of the internal forces. This adequate evaluation was given for a Saint Venant-Kirchhoff hyperelastic material. A generalization to other hyperelastic models was given by Laursen, who iteratively solved a new equation for each Gauss point to determine the adequate second Piola-Kirchhoff stress tensor. Another solution that avoids this iterative procedure leads to a general formulation of the second Piola-Kirchhoff stress tensor, was given by Gonzalez. This formulation is valid for general hyperelastic materials. The EMCA was recently extended to dynamic finite deformation plasticity by Meng and Laursen. Armero and Romero also introduced numerical dissipation in these conserving algorithms. This dissipation only affects the total energy but preserves the angular momentum. Moreover, it is proved to be stable in the non-linear range, contrarily to the generalized-algorithms. It is called Energy Dissipative Momentum Conserving algorithm or EDMC. Besides, Armero and Petöcz proposed a treatment of contact interactions in a consistent way in the non-linear range. All the conserving methods described above were established for hyperelastic materials. We have recently established a new expression of the internal forces for the hypoelastic materials using the final rotation scheme. When associated with the mid-point scheme, this expression ensures the conservation laws of the mechanics for a hypoelastic constitutive model. Moreover, using the radial return mapping, we prove that this adaptation remains consistent with the Drucker postulate when plastic deformation occurs. In this work we introduce numerical dissipation in a consistent way for such hypoelastic constitutive models. Moreover, we propose a method to enhance the contact simulation proposed by Armero and Petöcz to surfaces with discontinuous normal as is the case when the two bodies in contact are deformable and are thus discretized by finite elements. With such improvements, we are able to simulate complex simulations of impact such as a blade-loss in a turbo engine. [less ▲]

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See detailLe déséquilibre de force musculaire favorise-t-il la survenue d’une lésion ?
Croisier, Jean-Louis ULg

in Actes du 2ème Colloque Médico-sportif « Entre laboratoire et terrain » (Liège) (2005, February)

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See detailPourquoi s'intéresser au paysage ?
Partoune, Christine ULg

in TRACeS de ChanGements (2005), 169

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See detailFollicular dendritic cells related to nerve fibres and cellular prion protein expression in ileal and jejunal Peyer’s patches of cows and calves
Defaweux, Valérie ULg; Antoine, Nadine ULg; Dorban, G. et al

Poster (2005, February)

Prion pathogenesis following oral exposure is thought to involve gut-associated lymphoid tissue, which includes Peyer’s patches (PP). Before neuroinvasion, early accumulation of infectious prion protein ... [more ▼]

Prion pathogenesis following oral exposure is thought to involve gut-associated lymphoid tissue, which includes Peyer’s patches (PP). Before neuroinvasion, early accumulation of infectious prion protein (PrPsc) takes place on follicular dendritic cells (FDC) which are resident cells in germinal centres. The strain, the infection pathway and the lesions in the central nervous system are similar between bovine spongiform encephalopathy (BSE) and variant Creutzfeldt Jakob diseases. But in BSE, the agent tropism differs from lymphoid organs. Only bovine ileal PP are infectious. In order to study the replication and the possible ways of neuroinvasion of PrPsc in bovine PP, we studies the expression of cellular prion protein (PrPc), necessary for PrPsc accumulation, and compared the innervation of germinal centres related to FDC on ileal and jejunal PP of cows and calves. We performed classical immunoperoxydase staining and double immunofluorescence staining analyzed with a confocal microscopy. Differences in the innervation of germinal centres and expression of PrPc were evident. More contacts between FDC and nerve fibres are observed in calves PP. PrPc expression, carried out with different anti-PrPc antibodies, highlighted a heterogeneous labelling between calves and cows PP. Such results permit us to show that the innervation of PP is a dynamic process which could influence the first way of neuroinvasion in prion diseases. Moreover differences in the affinity of some antibody for PrPc allow us to postulate that PrPc glycoforms differ with age of bovines and thus could interfere with PrPsc tropism. [less ▲]

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See detailCarte hydrogéologique du plateau d’Oulmès (Maroc)
Elbatloussi, Dounia; Cheddadi, Meriem; Dadi, Sliman et al

Report (2005)

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See detailImproving the alkalophilic performances of the Xyl1 xylanase from Streptomyces sp S38: Structural comparison and mutational analysis
De Lemos Esteves, Frédéric ULg; Gouders, T.; Lamotte-Brasseur, J. et al

in Protein Science : A Publication of the Protein Society (2005), 14(2), 292-302

Endo-beta-1,4-xylanases of the family 11 glycosyl-hydrolases are catalytically active over a wide range of pH. Xyl1 from Streptomyces sp. S38 belongs to this family, and its optimum pH for enzymatic ... [more ▼]

Endo-beta-1,4-xylanases of the family 11 glycosyl-hydrolases are catalytically active over a wide range of pH. Xyl1 from Streptomyces sp. S38 belongs to this family, and its optimum pH for enzymatic activity is 6. Xyn11 from Bacillus agaradhaerens and XylJ from Bacillus sp. 41M-1 share 85% sequence identity and have been described as highly alkalophilic enzymes. In an attempt to better understand the alkalophilic adaptation of xylanases, the three-dimensional structures of Xyn11 and Xyl1 were compared. This comparison highlighted an increased number of salt-bridges and the presence of more charged residues in the catalytic cleft as well as an eight-residue-longer loop in the alkalophilic xylanase Xyn11. Some of these charges were introduced in the structure of Xyl1 by site-directed mutagenesis with substitutions Y16D, S18E, G50R, N92D, A135Q, E139K, and Y186E. Furthermore, the eight additional loop residues of Xyn11 were introduced in the homologous loop of Xyl1. In addition, the coding sequence of the XylJ catalytic domain was synthesized by recursive PCR, expressed in a Streptomyces host, purified, and characterized together with the Xyl1 mutants. The Y186E substitution inactivated Xyl1, but the activity was restored when this mutation was combined with the G50R or S18E substitutions. Interestingly, the E139K mutation raised the optimum pH of Xyl1 from 6 to 7.5 but had no effect when combined with the N92D substitution. Modeling studies identified the possible formation of an interaction between the introduced lysine and the substrate, which could be eliminated by the formation of a putative salt-bridge in the N92D/E139K mutant. [less ▲]

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See detailEffect of concrete surface treatment on adhesion in repair systems
Garbacz, A.; Gorka, M.; Courard, Luc ULg

in Magazine of Concrete Research (2005), 57(1), 49-60

Existing concrete surfaces need to be roughened to a profile necessary to achieve mechanical interlocking with any repair material. In this study, different surface treatments (e.g. grinding, sandblasting ... [more ▼]

Existing concrete surfaces need to be roughened to a profile necessary to achieve mechanical interlocking with any repair material. In this study, different surface treatments (e.g. grinding, sandblasting, shotblasting, hand- and mechanical milling) were performed and the quality of the preparation established on the basis of three main parameters: surface geometry, superficial concrete microcracking and adhesion. Surface geometry was characterised on the basis of the measurement of surface profile-profilometry-and the analysis of statistical and amplitude parameters calculated from the waviness (lower frequencies) and the roughness (higher frequencies) profiles of the surface. Investigations were also performed to assess the quality of the superficial zone of concrete and cracks were systematically observed in relation to surface treatment where both scanning electron microscopy and light microscopy were used for analysis. Finally, a repair mortar with or without bond coat, was applied to the concrete substrates in order to measure adhesion. Relationships clearly show the effect of roughness on adhesion in the case where no bond coat was used and also the influence of the power of the surface treatment on the waviness shape of the profile and the presence of microcracks in the near-surface layer related to failure type. [less ▲]

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See detailFurther insight on carapid - holothuroid relationships
Parmentier, Eric ULg; Vandewalle, Pierre ULg

in Marine Biology (2005), 146(3), 455-465

Carapidae (or pearlfish) are eel-like fishes that live inside different invertebrates, such as holothurians, sea stars, or bivalves. Those of the genus Carapus are commensal and use their host as a ... [more ▼]

Carapidae (or pearlfish) are eel-like fishes that live inside different invertebrates, such as holothurians, sea stars, or bivalves. Those of the genus Carapus are commensal and use their host as a shelter, while Encheliophis species are parasitic and eat the host's gonads. In areas where they live in sympatry, C. boraborensis, C. homei, C. mourlani and E. gracilis are able to inhabit the same host species. Infestation is considered as monospecific when several conspecifics are observed in the same host. However, many aspects of this particular relation remain obscure, e.g. communication between carapids and the defence systems of the different protagonists (carapids and hosts). Experiments have been conducted in the field and laboratory to investigate several aspects of the carapids' relationships with their hosts. Sampling carried out in the Bay of Opunohu (Moorea, French Polynesia) determined the sex ratio of C. boraborensis (3:1) and C. homei (1:1) and their distribution rate within different Echinodermata. Our study showed that neither species was capable of determining whether a heterospecific already occupied a sea cucumber or not. They were, however, able to locate the sea cucumber's cloaca, due to the excurrent resulting from respiration. The sea cucumber's defence system (Cuverian tubules) minimises predator attacks, but is not effective against carapid intrusion. The Carapidae defence system is twofold. Due to a passive system related to the sea cucumber's low cloacal position, the Cuverian tubules are not expelled when fish enter the cloaca. Moreover, carapids resist sea cucumber toxins better than other reef fish. Their increased resistance might be related to their gills rather than to their mucus coating; however, the latter may assist the fish in resisting the sticky substances emitted by the Cuverian tubules. [less ▲]

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See detailMoisture profiles determination during convective drying using x-ray microtomography
Léonard, Angélique ULg; Blacher, Silvia ULg; Marchot, Pierre ULg et al

in Canadian Journal of Chemical Engineering (2005), 83(1), 127-131

The knowledge of internal moisture profiles which develop during drying is essential for model validation purposes, but they are difficult to determine experimentally. This paper shows that X-ray ... [more ▼]

The knowledge of internal moisture profiles which develop during drying is essential for model validation purposes, but they are difficult to determine experimentally. This paper shows that X-ray microtomography, together with image analysis, provides an accurate, non destructive and easy to use technique to determine moisture profiles. Results reported concern the drying of wastewater sludges whose management is becoming a real environmental challenge. An analysis of the development of moisture gradients at the sample external wall shows an influence of drying operating conditions. Finally, mass diffusion coefficients are estimated from the knowledge of both the moisture gradients and the drying flux. [less ▲]

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See detailPreparation, characterization and in vitro release properties of ibuprofen-loaded microspheres based on polylactide, poly(epsilon-caprolactone) and their copolymers
Zhu, K. J.; Li, Y.; Jiang, H. L. et al

in Journal of Microencapsulation (2005), 22(1), 25-36

In this paper, ibuprofen was encapsulated into microspheres by oil-in-water (o/w) emulsion solvent evaporation method. Biodegradable polymers with certain compositions and characteristics such as ... [more ▼]

In this paper, ibuprofen was encapsulated into microspheres by oil-in-water (o/w) emulsion solvent evaporation method. Biodegradable polymers with certain compositions and characteristics such as polylactide (PLA), poly(epsilon-caprolactone) (PCL) and their block copolymer were used to prepare the microspheres. The results indicate that, under the same processing conditions, the drug entrapment efficiency was similar (similar to 80%) for microspheres prepared with PLA and P(LA-b-CL) (78.7/21.3 by mole), but it was only 25.4% for PCL microspheres. The in vitro drug release rate decreased in the order of PCL, P(LA-b-CL) (78.7/21.3 by mole) and PLA microspheres. PCL microspheres showed more serious burst release during the first day (almost 80%) than P(LA-b-CL) (50%) and PLA microspheres (18%). The complete ibuprofen release duration from the last two kinds of microspheres exceeded I month. Characterization of the microspheres by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and polarized optical microscope (POM) revealed that ibuprofen was amorphous in PCL microspheres and partially crystalline in P(LA-h-CL) and PI-A microspheres. The different release behaviour of ibuprofen from the three kinds of microspheres could be attributed to the different crystallinity of the studied polymers and drug dispersion state in polymer matrices. All the above results suggest that the copolymer with a certain ratio of lactide to epsilon-caprolactone could have potential applications for long-term ibuprofen release. [less ▲]

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