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See detailThe paralogous salivary anti-complement proteins IRAC I and IRAC II encoded by Ixodes ricinus ticks have broad and complementary inhibitory activities against the complement of different host species.
Schroeder, Hélène ULg; Daix, Virginie; Gillet, Laurent ULg et al

in Microbes & Infection (2007), 9(2), 247-50

Several observations suggest that inhibition of the host complement alternative pathway by Ixodes tick saliva is crucial to achieve blood feeding. We recently described two paralogous anti-complement ... [more ▼]

Several observations suggest that inhibition of the host complement alternative pathway by Ixodes tick saliva is crucial to achieve blood feeding. We recently described two paralogous anti-complement proteins called Ixodes ricinus anti-complement (IRAC) proteins I and II co-expressed in I. ricinus salivary glands. Phylogenetic analyses suggested that these sequences were diversifying by a process of positive Darwinian selection, possibly leading to molecules with different biological properties. In the present study, we tested the hypothesis that each paralogue may have different inhibitory activities against the complement of different natural host species, thereby contributing to broaden the host range of I. ricinus ticks. IRAC I and IRAC II were tested against the complement of eight I. ricinus natural host species (six mammals and two birds). The results demonstrate that IRAC I and IRAC II have broad and complementary inhibition activities against the complement of different host species. This report is the first description of paralogous anti-complement molecules encoded by a pathogen with broad and complementary inhibitory activities against the complement of different host species. [less ▲]

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See detailParalysie non traumatique du nerf interosseux antébrachial postérieur liée à la pratique du vélo tout-terrain
WANG, François-Charles ULg; GOFFINET, Estelle ULg

in Lettre du Neurologue (La) : le Courrier du Spécialiste (2010)

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See detailParalysie non traumatique du nerf interosseux antébrachial postérieur liée à la pratique du VTT
Goffinet, Estelle; Zeevaert, Bernard; Claes, Frédérique et al

in Journal de Traumatologie du Sport (2004)

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See detailParalysie vélo-palatine et oculomotrice d'apparition brutale : une forme particulière de polyradiculonévrite
Franckart, Geneviève; Fakif, K.; Trippaerts, Marc ULg et al

in Comptes Rendus des Journées Annuelles de la Société Belge de Pédiatrie (1990)

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See detailLes paralysies du nerf moteur oculaire commun chez l'enfant: a propos d'une observation de tumeur germinale hypophysaire.
Kalenga, Mbu; COLLIGNON, Nathalie ULg; ANDRIS, Cécile ULg et al

in Bulletin de la Société Belge d'Ophtalmologie (2011), (318), 31-6

PURPOSE: Third cranial nerve palsies are unfrequent in childhood and adolescence and are most often congenital. The association of sellar germ cell tumor and ophthalmoplegia is considered as being very ... [more ▼]

PURPOSE: Third cranial nerve palsies are unfrequent in childhood and adolescence and are most often congenital. The association of sellar germ cell tumor and ophthalmoplegia is considered as being very rare at this age. CASE REPORT: A 11-year-old young girl was examined in emergency with a third left cranial nerve partial palsy associated with one- year duration history of hypopituitarism with insipid diabetes and growth retardation. Cerebral IRM revealed a tumor of the pituitary gland. In histopathological examination of pituitary gland biopsies, lesions were compatibles with a sellar germ cell tumor. CONCLUSION: Although they are most often of a congenital nature, third cranial nerve palsies in childhood may be secondary to other causes that should be always taken in mind. When they are secondary to a sellar tumor and according to the clinical presentation and the IRM, the histopahological examination of biopsies is mandatory to have a precise diagnosis. [less ▲]

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See detailParamagnetic nanoparticles as potential MRI contrast agents: characterization, NMR relaxation, simulations and theory
Quoc Lam Vuong; Van Doorslaer, Sabine; Bridot, Jean-Luc et al

in MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE (2012), 25(6), 467-478

Paramagnetic nanoparticles, mainly rare earth oxides and hydroxides, have been produced these last few years for use as MRI contrast agents. They could become an interesting alternative to iron oxide ... [more ▼]

Paramagnetic nanoparticles, mainly rare earth oxides and hydroxides, have been produced these last few years for use as MRI contrast agents. They could become an interesting alternative to iron oxide particles. However, their relaxation properties are not well understood. Magnetometry, H-1 and H-2 NMR relaxation results at different magnetic fields and electron paramagnetic resonance are used to investigate the relaxation induced by paramagnetic particles. When combined with computer simulations of transverse relaxation, they allow an accurate description of the relaxation induced by paramagnetic particles. For gadolinium hydroxide particles, both T (1) and T (2) relaxation are due to a chemical exchange of protons between the particle surface and bulk water, called inner sphere relaxation. The inner sphere is also responsible for T (1) relaxation of dysprosium, holmium, terbium and erbium containing particles. However, for these latter compounds, T (2) relaxation is caused by water diffusion in the field inhomogeneities created by the magnetic particle, the outer-sphere relaxation mechanism. The different relaxation behaviors are caused by different electron relaxation times (estimated by electron paramagnetic resonance). These findings may allow tailoring paramagnetic particles: ultrasmall gadolinium oxide and hydroxide particles for T (1) contrast agents, with shapes ensuring the highest surface-to-volume ratio. All the other compounds present interesting T (2) relaxation performance at high fields. These results are in agreement with computer simulations and theoretical predictions of the outer-sphere and static dephasing regime theories. The T (2) efficiency would be optimum for spherical particles of 40-50 nm radius. [less ▲]

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See detailParamagnetic reentrance of ac screening: Evidence of vortex avalanches in Pb thin films
Silhanek, Alejandro ULg; Raedts, S.; Moshchalkov, V. V.

in Physical Review. B : Condensed Matter (2004), 70(14),

We have studied the influence of a square array of pinning centers on the dynamics of vortex avalanches in Pb thin films by means of ac- and dc-magnetization measurements. Close to the superconducting ... [more ▼]

We have studied the influence of a square array of pinning centers on the dynamics of vortex avalanches in Pb thin films by means of ac- and dc-magnetization measurements. Close to the superconducting transition T-c, the commensurability between the vortex lattice and the pinning array leads to the well known local increments of the critical current. As temperature T decreases, matching features progressively fade out and eventually disappear. Further down in temperature, vortex avalanches develop and dominate the magnetic response. These avalanches manifest themselves as jumps in the dc magnetization and produce a lower ac shielding, giving rise to a paramagnetic reentrance in the ac screening chi(')(T). Within the flux-jump regime, two subregimes can be identified. Close to the boundary where vortex avalanches develop, the field separation between consecutive jumps follows the periodicity of the pinning array and a field- and temperature-dependent screening is observed. In this regime, the response also depends on frequency f in agreement with theoretical models for magnetothermal instabilities. At low enough temperatures and fields, the screening saturates to a constant value independent of T, H, and f, where jumps are randomly distributed. We have also found that vortex instabilities occupy a larger portion of the H-T diagram in patterned samples than in films without nanoengineered pinning sites. Finally, we discuss the possible origin of the vortex avalanches and compare our results with previous experimental and theoretical studies. [less ▲]

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See detailParameter estimation and structural model updating using modal methods in the presence of nonlinearity
Golinval, Jean-Claude ULg

Conference given outside the academic context (2009)

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See detailParameter estimation in biochemical reaction networks: An observer-based approach
Fey, Dirk; Bullinger, Eric ULg

Conference (2008, March 27)

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See detailParameter estimation in kinetic reaction models using nonlinear observers is facilitated by model extensions
Fey, Dirk ULg; Findeisen, Rolf; Bullinger, Eric ULg

in 17th IFAC World Congress, Seoul, Korea (2008)

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See detailParameter estimation using slug tests : application to a heat injection and storage experiment
Vandenbohede, Alexander; Louwyck, Andy; Daoudi, Moubarak et al

Poster (2011, September 19)

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See detailParameter identification and shape/process optimization in metal forming simulation
Kleinermann, J. P.; Ponthot, Jean-Philippe ULg

in Journal of Materials Processing Technology (2003), 139(1-3), 521-526

Nowadays, computer simulations of metal forming processes using the finite element method (FEM) have reached some level of maturity. The purpose of inverse problems is to determine the simulation input ... [more ▼]

Nowadays, computer simulations of metal forming processes using the finite element method (FEM) have reached some level of maturity. The purpose of inverse problems is to determine the simulation input data for one or more of these forming processes, leading to a desired result. The first example is called parameter identification. This consists in evaluating the material parameters for material behavior laws that would lead to the most accurate model, minimizing the difference between experimental results and the corresponding FEM simulation. The second example is initial geometry and tool shape design, consisting in determining the initial shape of the specimen and/or the shape of the forming tools, in order to provide the desired final geometry after the forming process. Both inverse problem examples can be formulated as optimization problems. In this paper, the authors propose to solve these optimization problems with different non-linear optimization methods and to compare their efficiency. (C) 2003 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailParameter identification for biological models
Fey, Dirk ULg

Doctoral thesis (2011)

This thesis concerns the identification of dynamic models in systems biology. and is structured into two parts. Both parts concern building dynamic models from observed data, but are quite different in ... [more ▼]

This thesis concerns the identification of dynamic models in systems biology. and is structured into two parts. Both parts concern building dynamic models from observed data, but are quite different in perspective, rationale and mathematics. The first part considers the development of novel identification techniques that are particularly tailored to (molecular) biology and considers two approaches. The first approach reformulates the parameter estimation problem as a feasibility problem. This reformulation allows the invalidation of models by analysing entire parameter regions. The second approach utilises nonlinear observers and a transformation of the model equations into parameter free coordinates. The parameter free coordinates allow the design of a globally convergent observer, which in turn estimates the parameter values, and further, allows to identify modelling errors or unknown inputs/influences. Both approaches are bottom up approaches that require a mechanistic understanding of the underlying processes (in terms of a biochemical reaction network) leading to complex nonlinear models. The second part is an example of what can be done with classical, well developed tools from systems identification when applied to hitherto unattended problems.In particular, part two of my thesis develops a modelling framework for rat movements in an experimental setup that it widely used to study learning and memory.The approach is a top down approach that is data driven resulting in simple linear models. [less ▲]

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See detailParameter identification for inverse problems in metal forming simulation
KLEINERMANN, J. P.; Ponthot, Jean-Philippe ULg; Hogge, Michel ULg

in Proceedings of FIELD ANALYSIS FOR DETERMINATION OF MATERIAL PARAMETERS. EXPERIMENTAL AND NUMERICAL ASPECTS (2003)

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See detailParameter Identification in a Model of the Cardiovascular System Including the Atria
Pironet, Antoine ULg; Revie, James A.; Paeme, Sabine ULg et al

in 10th Belgian Day on Biomedical Engineering (2011, December 02)

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See detailParameter Identification in a Model of the Cardiovascular System Including the Atria
Pironet, Antoine ULg; Revie, James A.; Paeme, Sabine ULg et al

Poster (2011, December 02)

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See detailParameter Identification of Material Models using the "GCMMA" method
KLEINERMANN, J. P.; Ponthot, Jean-Philippe ULg

in Proceedings of "NUMIFORM'98, Simulation of Materials Processing: Theory, Methods and Applications (1998, June)

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See detailParameter identification of nolinear mechanical systems using POD
Lenearts, Vincent; Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in 18th International Modal Analysis Conference, San Antonio, 2000 (2000)

Proper Orthogonal Decomposition (POD), also known as Karhunen-Loeve decomposition, or principal components analysis (PCA), is emerging as a useful experimental tool in dynamics and vibrations. The POD is ... [more ▼]

Proper Orthogonal Decomposition (POD), also known as Karhunen-Loeve decomposition, or principal components analysis (PCA), is emerging as a useful experimental tool in dynamics and vibrations. The POD is a statistical pattern analysis technique for finding the dominant structures in an ensemble of spatially distributed data. These structures can be used as an orthogonal basis for efficient representation of the ensemble. The Proper Orthogonal Modes (POM) have been interpreted mainly as empirical system modes. They have been shown to represent the optimal distributions of kinetic energy or power, and the proper orthogonal values indicate the power associated with these principal distributions. We investigate the use of the proper orthogonal modes of displacements for the identification of parameters of nonlinear dynamical structures with an optimization procedure based on the difference between the experimental and simulated POM. A numerical example of a beam with a local nonlinear component will illustrate the method. [less ▲]

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See detailParameter Identification Using Inverse Problems Methodology in Metal Forming Simulation
KLEINERMANN, J. P.; Stainier, Laurent ULg; Ponthot, Jean-Philippe ULg

in Proc. of the Second International Conference on Engineering Computational Technology “Finite Element Techniques and development (2000)

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See detailParameter identification of the STICS crop model, using an accelerated formal MCMC approach
Dumont, Benjamin ULg; Leemans, Vincent ULg; Mansouri, Majdi ULg et al

in Environmental Modelling & Software (2014), 52

This study presents a Bayesian approach for the parameters’ identification of the STICS crop model based on the recently developed Differential Evolution Adaptive Metropolis (DREAM) algorithm. The ... [more ▼]

This study presents a Bayesian approach for the parameters’ identification of the STICS crop model based on the recently developed Differential Evolution Adaptive Metropolis (DREAM) algorithm. The posterior distributions of nine specific crop parameters of the STICS model were sampled with the aim to improve the growth simulations of a winter wheat (Triticum aestivum L.) culture. The results obtained with the DREAM algorithm were initially compared to those obtained with a Nelder-Mead Simplex algorithm embedded within the OptimiSTICS package. Then, three types of likelihood functions implemented within the DREAM algorithm were compared, namely the standard least square, the weighted least square, and a transformed likelihood function that makes explicit use of the coefficient of variation (CV). The results showed that the proposed CV likelihood function allowed taking into account both noise on measurements and heteroscedasticity which are regularly encountered in crop modelling [less ▲]

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