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See detailRGD surface functionalization of the hydrophilic acrylic intraocular lens material to control posterior capsular opacification
Huang, Yi-Shiang ULg; Bertrand, Virginie ULg; Bozukova, Dimitriya et al

in PLoS ONE (in press)

Posterior Capsular Opacification (PCO) is the capsule fibrosis developed on implanted IntraOcular Lens (IOL) by the de-differentiation of Lens Epithelial Cells (LECs) undergoing Epithelial Mesenchymal ... [more ▼]

Posterior Capsular Opacification (PCO) is the capsule fibrosis developed on implanted IntraOcular Lens (IOL) by the de-differentiation of Lens Epithelial Cells (LECs) undergoing Epithelial Mesenchymal Transition (EMT). Literature has shown that the incidence of PCO is multifactorial including the patient’s age or disease, surgical technique, and IOL design and material. Reports comparing hydrophilic and hydrophobic acrylic IOLs have shown that the former has more severe PCO. On the other hand, we have previously demonstrated that the adhesion of LECs is favored on hydrophobic compared to hydrophilic materials. By combining these two facts and contemporary knowledge in PCO development via the EMT pathway, we propose a biomimetically inspired strategy to promote LEC adhesion without de-differentiation to reduce the risk of PCO development. By surface grafting of a cell adhesion molecule (RGD peptide) onto the conventional hydrophilic acrylic IOL material, the surface-functionalized IOL can be used to reconstitute a capsule-LEC-IOL sandwich structure, which has been considered to prevent PCO formation in literature. Our results show that the innovative biomaterial improves LEC adhesion, while also exhibiting similar optical (light transmittance, optical bench) and mechanical (haptic compression force, IOL injection force) properties compared to the starting material. In addition, compared to the hydrophobic IOL material, our bioactive biomaterial exhibits similar abilities in LEC adhesion, morphology maintenance, and EMT biomarker expression, which is the crucial pathway to induce PCO. The in vitro assays suggest that this biomaterial has the potential to reduce the risk factor of PCO development. [less ▲]

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See detailEstimation of sarcopenia prevalence using various assessment tools
Beaudart, Charlotte ULg; Reginster, Jean-Yves ULg; Slomian, Justine ULg et al

in Experimental Gerontology (in press)

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See detailPersonnalité antisociale et psychopathologie
Englebert, Jérôme ULg

Conference (2015, July 14)

Notre communication a pour objectif de confronter les critères de la personnalité antisociale du DSM-IV et du DSM-5 à une réflexion psychopathologique. Nous commencerons par une analyse des différentes ... [more ▼]

Notre communication a pour objectif de confronter les critères de la personnalité antisociale du DSM-IV et du DSM-5 à une réflexion psychopathologique. Nous commencerons par une analyse des différentes contradictions propres au diagnostic qui nous mèneront à l’identification du critère « primaire » de cette entité qui est l’« incapacité à se conformer aux lois et normes sociales ». Nous confronterons ensuite à des situations cliniques l’hétérogénéité des profils pouvant répondre à ce diagnostic. Nos constats nous conduiront à mettre en doute la validité apparente du concept de personnalité antisociale, puisqu’il recouvre des modes de fonctionnement psychologique variés. La valeur discriminative faible, en matière de fonctionnement psychologique, suggère que c’est une dimension autre que psychopathologique qui organise ce diagnostic. Dénuée de toute attention pour les modes d’interactions, pour le vécu émotionnel et pour les états de subjectivité, la notion de personnalité antisociale ne porte pas d’intérêt à l’individu qu’elle catégorise, mais bien à l’acte délinquant commis par ce dernier. Nous conclurons sur le constat de l’absence de dimension psychopathologique de la personnalité antisociale, qui se révèle être un diagnostic principalement criminologique, à l’inverse des fondements de l’éthique psychopathologique. [less ▲]

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See detailSemiótica de la acción: textualización y notación
Dondero, Maria Giulia ULg

in Tópicos del seminario (2015), 31

Our essay focuses on some methodological issues concerning the semiotic analysis of practice. We will initially retrace the debate about the epistemological relationship between text and action, outlining ... [more ▼]

Our essay focuses on some methodological issues concerning the semiotic analysis of practice. We will initially retrace the debate about the epistemological relationship between text and action, outlining the forms of enunciative praxis through different levels of pertinence analysis. Secondly, we propose the concept of ‘textualization’ as a mediation between text and action: textualizations (photographs, videos, notes) organize and represent practices which are in themselves ephemeral and elusive. Finally, we will consider the textual diagrammatization that we call ‘notation’: this analytical form of mediation between text and practice does not have the same status of in-vivo textualisations, but it works like an ex-post reconstruction which highlights the main gestures and exchanges while performing their grammaticalization. A more general aim of this essay is an enquiry into the legitimate objects of textual semiotics: what are the objects that it can analyze without betraying its principle of immanence, but also without being confined to it and, as a consequence, being unable to analyze practices and respond to topical questions on social issues and on the research in the human sciences? [less ▲]

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See detailAnisotropy and tension-compression asymmetry modeling of the room temperature plastic response of Ti-6A1-4V
Tuninetti, Victor; Gilles, Gaëtan ULg; Pardoen, Thomas et al

in International Journal of Plasticity (2015)

The mechanical behavior of the alloy Ti-6A1-4V is characterized using uniaxial tension, uniaxial compression, simple shear and place strain tests in three orthogonal material directions. The experimental ... [more ▼]

The mechanical behavior of the alloy Ti-6A1-4V is characterized using uniaxial tension, uniaxial compression, simple shear and place strain tests in three orthogonal material directions. The experimental results reveal tension/compression asymmetry, anisotropic yielding and anisotropic strain-hardening. These features are incorporated into an elasto-plastic constitutive law based on the macroscopic orthotropic yield criterion "CPB06" adapted to hexagonal metals. A new identification method for the yield criterion parameters is proposed by inverse modeling of the axial strain field compression specimens in the three orthogonal directions of the material. The sensitivity of different sets of material parameters to the identification method is also analysed and the capacity of the model to accurately predict the forces and displacement field is discussed. A validation of the best set of identified CPB06material parameters is performed by comparing the load-displacement curves in different loading directions for tensile tests on notched round bars with different levels of stress triaxiality and for compression tests on elliptical cross-section specimens, both tests involving multiaxial strain fields and large deformations. [less ▲]

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See detailSubjectivations politiques et épreuve de soi. Le cas Sartre/Fanon
Cormann, Grégory ULg

Scientific conference (2015, March 05)

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See detailLes Grecs ont-ils étudié le latin ?
Rochette, Bruno ULg

Scientific conference (2015, February 19)

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See detailTypus melancholicus et recommandations pratiques
Ramackers, Amélia; Englebert, Jérôme ULg

Scientific conference (2015, February 16)

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See detailQuand la clinique bouscule les concepts
Englebert, Jérôme ULg

Scientific conference (2015, February 11)

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See detailSuppression of Limit Cycle Oscillations using the Nonlinear Tuned Vibration Absorber
Habib, Giuseppe ULg; Kerschen, Gaëtan ULg

in Proceeding IMAC XXXIII A Conference and Exposition on Structural Dynamics, Orlando 2-5 February 2015 (2015, February 03)

The objective of the present study is to mitigate, or even completely eliminate, the limit cycle oscillations in mechanical systems using a passive nonlinear absorber, termed the nonlinear tuned vibration ... [more ▼]

The objective of the present study is to mitigate, or even completely eliminate, the limit cycle oscillations in mechanical systems using a passive nonlinear absorber, termed the nonlinear tuned vibration absorber (NLTVA). An unconventional aspect of the NLTVA is that the mathematical form of its restoring force is not imposed a priori, as it is the case for most existing nonlinear absorbers. The NLTVA parameters are determined analytically using stability and bifurcation analyses, and the resulting design is validated numerically using the MATCONT software. The proposed developments are illustrated using a Van der Pol-Du ng primary system. [less ▲]

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See detailEffects of low dose endosulfan exposure on brain neurotransmitter levels in the African clawed frog Xenopus laevis
Preud'Homme, Valérie; Milla, Sylvain; Gillardin, Virginie et al

in Chemosphere (2015), 120(2), 357-364

Understanding the impact of pesticides in amphibians is of growing concern to assess the causes of their decline. Among pesticides, endosulfan belongs to one of the potential sources of danger because of ... [more ▼]

Understanding the impact of pesticides in amphibians is of growing concern to assess the causes of their decline. Among pesticides, endosulfan belongs to one of the potential sources of danger because of its wide use and known effects, particularly neurotoxic, on a variety of organisms. However, the effect of endosulfan was not yet evaluated on amphibians at levels encompassing simultaneously brain neurotransmitters and behavioural endpoints. In this context, tadpoles of the African clawed frog Xenopus laevis were submitted to four treatments during 27 d: one control, one ethanol control, and two low environmental concentrations of endosulfan (0.1 and 1 μg L−1). Endosulfan induced a significant increase of brain serotonin level at both concentrations and a significant increase of brain dopamine and GABA levels at the lower exposure but acetylcholinesterase activity was not modified by the treatment. The gene coding for the GABA transporter 1 was up-regulated in endosulfan contaminated tadpoles while the expression of other genes coding for the neurotransmitter receptors or for the enzymes involved in their metabolic pathways was not significantly modified by endosulfan exposure. Endosulfan also affected foraging, and locomotion in links with the results of the physiological assays, but no effects were seen on growth. These results show that low environmental concentrations of endosulfan can induce adverse responses in X. laevis tadpoles. At a broader perspective, this suggests that more research using and linking multiple markers should be used to understand the complex mode of action of pollutants. [less ▲]

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See detailAntoine Galland et l'épigraphie
Famerie, Etienne ULg

in Bauden, Frédéric; Waller, Richard (Eds.) Colloque international A. Galland (2015, February)

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See detailLa démocratie sous expertise. Médias, think tanks et privatisation du débat européen (en préparation, parution début 2015)
Geuens, Geoffrey ULg

Book published by Éditions du Croquant, collection "Savoir / Agir" (2015)

L’ouvrage questionne la genèse des think tanks eurofédéralistes participant à la fabrication et à la légitimation des politiques d’intégration, avant de s’intéresser à ces autres agents sociaux de ... [more ▼]

L’ouvrage questionne la genèse des think tanks eurofédéralistes participant à la fabrication et à la légitimation des politiques d’intégration, avant de s’intéresser à ces autres agents sociaux de production et de diffusion de la pensée européenne que sont notamment les correspondants bruxellois et éditorialistes de quelques grands médias européens. L’ouvrage montre combien le discours journalistique sur l’Europe et le discours de certains « spécialistes » des questions européennes, qui trouve aussi à s’exprimer dans l’espace médiatique, sont la plupart du temps limités à quelques expressions stéréotypées et argumentaires clichés s’expliquant autant par la position occupée dans le champ du pouvoir par les agents qui s’en font les relais que par les dispositions de ces mêmes agents sociaux à l’égard du « projet européen ». [less ▲]

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See detailExperimental modal analysis of nonlinear structures using broadband data
Noël, Jean-Philippe ULg; Renson, Ludovic ULg; Grappasonni, Chiara ULg et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXIII (2015, February)

The objective of the present paper is to develop a rigorous identification methodology of nonlinear normal modes (NNMs) of engineering structures. This is achieved by processing experimental measurements ... [more ▼]

The objective of the present paper is to develop a rigorous identification methodology of nonlinear normal modes (NNMs) of engineering structures. This is achieved by processing experimental measurements collected under broadband forcing. The use of such a type of forcing signal allows to excite multiple NNMs simultaneously and, in turn, to save testing time. A two-step methodology integrating nonlinear system identification and numerical continuation of periodic solutions is proposed for the extraction of the individual NNMs from broadband input and output data. It is demonstrated using a numerical cantilever beam possessing a cubic nonlinearity at its free end. The proposed methodology can be viewed as a nonlinear generalization of the phase separation techniques routinely utilized for experimental modal analysis of linear structures. The paper ends with a comparison between this new nonlinear phase separation technique and a previously-developed nonlinear phase resonance method. [less ▲]

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See detailExperimental nonlinear identification of an aircraft with bolted connections
De Filippis, Giovanni; Noël, Jean-Philippe ULg; Kerschen, Gaëtan ULg et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXIII (2015, February)

Aircraft structures are known to be prone to nonlinear phenomena, especially as they constantly become lighter and hence more flexible. One specific challenge that is regularly encountered is the modeling ... [more ▼]

Aircraft structures are known to be prone to nonlinear phenomena, especially as they constantly become lighter and hence more flexible. One specific challenge that is regularly encountered is the modeling of the mounting interfaces between aircraft subcomponents. Indeed, for large amplitudes of vibration, such interfaces may loosen and, in turn, trigger complex mechanisms such as friction and clearances. In this context, the present work intends to investigate the nonlinear dynamics of the Morane–Saulnier Paris aircraft, accessible at ONERA. This aircraft possesses multiple bolted connections between two external fuel tanks and wing tips. The objective of the paper is specifically to carry out an adequate identification of the numerous nonlinearities affecting the dynamics of this full-scale structure. Nonlinearity detection and the subsequent subspace-based parameter estimation have been performed on experimental data, collected during an on-ground test campaign. Nonlinearity detection is first achieved by the comparison of frequency response functions estimated at low excitation level, with those obtained at high amplitude level, yielding insight towards accurately characterizing the behavior of the bolted connections. Then, a nonlinear subspace identification method is applied to measured data to estimate the linear and nonlinear parameters of the structure and novel strategies and tools that overcome specific arisen problems are developed. [less ▲]

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See detailNonlinear generalization of Den Hartog׳s equal-peak method
Habib, Giuseppe ULg; Detroux, Thibaut ULg; Viguié, Régis et al

in Mechanical Systems & Signal Processing (2015), 52-53

This study addresses the mitigation of a nonlinear resonance of a mechanical system. In view of the narrow bandwidth of the classical linear tuned vibration absorber, a nonlinear absorber, termed the ... [more ▼]

This study addresses the mitigation of a nonlinear resonance of a mechanical system. In view of the narrow bandwidth of the classical linear tuned vibration absorber, a nonlinear absorber, termed the nonlinear tuned vibration absorber (NLTVA), is introduced in this paper. An unconventional aspect of the NLTVA is that the mathematical form of its restoring force is tailored according to the nonlinear restoring force of the primary system. The NLTVA parameters are then determined using a nonlinear generalization of Den Hartog׳s equal-peak method. The mitigation of the resonant vibrations of a Duffing oscillator is considered to illustrate the proposed developments. [less ▲]

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See detailExperimental demonstration of a 3D-printed nonlinear tuned vibration absorber
Grappasonni, Chiara ULg; Habib, Giuseppe ULg; Detroux, Thibaut ULg et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXIII (2015, February)

Engineering structures are designed to be lighter and more flexible, hence reducing the extent of application of linear dynamic models. Concurrently, vibration mitigation is required for enhancing the ... [more ▼]

Engineering structures are designed to be lighter and more flexible, hence reducing the extent of application of linear dynamic models. Concurrently, vibration mitigation is required for enhancing the performance, comfort or safety in real-life applications. Passive linear vibration absorbers are purpose-built, often designed using Den Hartog's equal-peak strategy. However, nonlinear systems are known to exhibit frequency-energy-dependent oscillations which linear absorbers cannot effectively damp out. In this context, the paper introduces a new nonlinear tuned vibration absorber (NLTVA) whose nonlinear functional form is tailored according to the frequency-energy dependence of the nonlinear primary structure. The NLTVA design aims at ensuring equal peaks in the nonlinear receptance function for an as large as possible range of forcing amplitudes, hence generalizing Den Hartog's method to nonlinear systems. Our focus in this study is on experimental demonstration of the NLTVA performance using a primary structure consisting of a cantilever beam with a geometrically nonlinear component at its free end. The absorber is implemented using a doubly-clamped beam fabricated thanks to 3D printing. The NLTVA performance is also compared with that of the classical linear tuned vibration absorber. [less ▲]

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See detailUsing shear strain localisation to model the fracturing around gallery in unsaturated Callovo-Oxfordian claystone
Pardoen, Benoît ULg; Levasseur, Séverine ULg; Collin, Frédéric ULg

in Chau, Kam Tim; Zhao, Jidong (Eds.) Bifurcation and Degradation of Geomaterials in the New Millennium (2015, January 28)

Galleries drilling leads to damage propagation, fracturing and properties modifications in the surrounding medium. The prediction of the damaged zone behaviour is an important matter and needs to be ... [more ▼]

Galleries drilling leads to damage propagation, fracturing and properties modifications in the surrounding medium. The prediction of the damaged zone behaviour is an important matter and needs to be properly assessed. To do so the fractures can be modelled using shear strain localisation. The coupled local second gradient model is used under unsaturated conditions to correctly model the strain localisation behaviour. The permeability evolution and the rock desaturation due to air ventilation in galleries are considered. Finally, a hydro-mechanical modelling of a gallery excavation in Callovo-Oxfordian claystone is performed leading to a fairly good representation of the damaged zone. [less ▲]

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