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See detailCdc42 downregulates MMP-1 expression by inhibiting the ERK1/2 pathway.
Deroanne, Christophe ULg; Hamelryckx, Delphine; Ho, Thi Thanh Giang ULg et al

in Journal of Cell Science (2005), 118(Pt 6), 1173-83

The small GTPases of the Rho family are key intermediates in cellular signalling triggered by activated cell-adhesion receptors. In this study, we took advantage of RNA interference (RNAi) using small ... [more ▼]

The small GTPases of the Rho family are key intermediates in cellular signalling triggered by activated cell-adhesion receptors. In this study, we took advantage of RNA interference (RNAi) using small interfering RNAs (siRNAs) to define the roles of the best-characterized members of the RhoGTPase family, RhoA, Rac1 and Cdc42, in the control of MMP-1, MMP-2 and type-I-collagen expression in normal human skin fibroblasts (HSFs). A specific and long-lasting repression, up to 7 days after transfection, of the three GTPases was achieved by transient transfection of specific siRNA. The silencing of Cdc42, but not that of RhoA or Rac1, induced a 15-fold increase in MMP-1 secretion. This upregulation was confirmed at the mRNA level and observed with two different siRNAs targeting Cdc42. Such a regulation was also observed in various human cell lines and was rescued by re-expressing wild-type Cdc42 encoded by a construct bearing silent mutations impeding its recognition by the siRNA. By contrast, MMP-2 and type-I-collagen expression was not affected by the individual silencing of each Rho GTPase. Cytokine protein array, enzyme-linked immunosorbent assays and reverse-transcription PCR measurements revealed that ablation of Cdc42 induced an overexpression of interleukin 8 and MCP-1. Although these cytokines are known to induce the expression of MMP-1, we showed that they were not involved in the Cdc42-mediated upregulation of MMP-1. Silencing of Cdc42 also induced an increased phosphorylation of ERK1/2 and p38 MAP kinase. The use of chemical inhibitors on Cdc42-ablated cells revealed that the upregulation of MMP-1 is dependent on the ERK1/2 pathways, whereas the p38 MAP kinase pathway displayed an inhibitory role. Simultaneous knock-down of two or three Rho GTPases allowed us to demonstrate that the RhoA-ROCK pathway was not involved in this regulation but that the silencing of Rac1 reduced the effect of Cdc42 suppression. These data suggest that, in vivo, when cell/extracellular-matrix interactions via integrins induce cytoskeleton organization, MMP-1 expression is maintained at a low level by Cdc42 via a repression of the Rac1 and ERK1/2 pathways. Therefore, Cdc42 contributes to ECM homeostasis and connective tissue integrity. [less ▲]

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See detailPas d’avenir sans les filles
Lafontaine, Dominique ULg

in TRACeS de ChanGements (2005), 170(2), 2

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See detailL'évaluation des compétences, une entreprise impossible ? (Résolution de problèmes complexes et maîtrise de procédures mathématiques)
Crahay, Marcel ULg; Detheux, Monique

in Mesure et Evaluation en Education [=MEE] (2005), 28(1), 57-58

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See detailDiabetes mellitus in the elderly: insulin resistance and/or impaired insulin secretion?
Scheen, André ULg

in Diabètes & Métabolism (2005), 31 Spec No 2

Elderly people are more glucose intolerant and insulin resistant than young individuals, and many of them will develop type 2 diabetes. It remains, however, controversial whether this decrease in function ... [more ▼]

Elderly people are more glucose intolerant and insulin resistant than young individuals, and many of them will develop type 2 diabetes. It remains, however, controversial whether this decrease in function is due to an inevitable consequence of "biological aging" or due to environmental or lifestyle variables. Indeed, increased adiposity/altered fat distribution, decreased fat free mass/abnormal muscle composition, poor dietary habits and physical inactivity all contribute to reduce insulin sensitivity. Insulin resistance in elderly people appears to predominate in skeletal muscle, whereas hepatic glucose output seems to be almost unaffected. Several abnormalities in islet beta-cell and insulin secretion were also pointed out in elderly people such as increased amyloid deposition and decreased amylin secretion, impaired insulin secretion pulsatility, decreased insulin sensitivity of pancreatic beta-cells to insulinotropic gut hormones and diminished insulin response to non-glucose stimuli such as arginine. Controversial results were reported concerning the effects of aging on absolute insulin secretion in response to oral or intravenous glucose. However, insulin secretion appears to decrease with age, with significantly diminished beta-cell sensitivity and acute insulin response to glucose, provided it is analyzed relative to concomitant decreased insulin sensitivity. Thus, there is an interplay between decreased insulin secretion and increased insulin resistance that largely explains the abnormal glucose metabolism seen in elderly. Weight loss, especially reduction of abdominal adiposity, and increased physical activity may contribute to improve insulin sensitivity and glucose tolerance, and prevent the development of type 2 diabetes in elderly people. [less ▲]

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See detailL'anémie par spoliation sanguine volontaire : le syndrome de Lasthénie de Ferjol
Farcy, L.; Fillet, Georges ULg; Couvreur, Véronique ULg et al

in Revue Médicale de Liège (2005), 60(9), 719-723

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See detailL'image du mois. Une image de "lâcher de ballons" à l'imagerie thoracique
Wauters, O.; Sautois, Brieuc ULg; Fillet, Georges ULg

in Revue Médicale de Liège (2005), 60

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See detailQuelles indications pour les statines hormis le traitement de l'hypercholesterolemie?
Scheen, André ULg; Sadzot, Bernard ULg

in Revue Médicale Suisse (2005), 1(30), 19541956-9

Statins are essential drugs for the prevention of coronary and cerebral vascular complications. Besides their specific cholesterol-lowering effect, these agents exert various pleiotropic effects, which ... [more ▼]

Statins are essential drugs for the prevention of coronary and cerebral vascular complications. Besides their specific cholesterol-lowering effect, these agents exert various pleiotropic effects, which probably contribute to the cardiovascular protection, but may also play a favourable effect in various other pathologies. Some recent data suggested that statins may play a positive effect in the prevention of Alzheimer disease and colorectal cancer. In contrast, after some initial hope, recent observations in the field of osteoporosis prevention provided discordant and finally rather disappointing results. New prospective studies are mandatory before accepting such new potential indications of statins. [less ▲]

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See detailDe la plus-value therapeutique au surcout d'un nouveau medicament: a propos d'un hiatus croissant.
Scheen, André ULg

in Revue Médicale Suisse (2005), 1(30), 1931-2

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See detailEsquisse d’une émotion théorique
Cormann, Grégory ULg

in Von Wroblewsky, Vincent (Ed.) Pourquoi Sartre ? (2005)

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See detailStructurer ses acquis en sciences : le rôle de l'écrit
Giot, Bernadette ULg; Quittre, Valérie ULg

in Site du Ministère de la Communauté française de Belgique (2005)

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See detailResearch on the students ’ motivation in physical education
Cloes, Marc ULg

in Carreiro da Costa, F.; Cloes, Marc; Gonzalez Valeiro, M. (Eds.) The art and science of teaching in physcal education and sport. A homage to Maurice Piéron (2005)

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See detailAnalyse des structures mises en place à l'intention des sportifs de haut niveau de l'enseignement supérieur. Comparaison dans différentes régions et pays
Polis, Arianne; Cloes, Marc ULg

Book published by ULg - Département des Sciences de la motricité - n° dépôt légal: D/2005/10.095/1 (2005)

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See detailThe situation of school physical education in Belgium
De Knop, Paul; Theeboom, M.; Huts, K. et al

in Pühse, U.; Gerber, M. (Eds.) International comparison of PE (2005)

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See detailRandom Subwindows for Robust Image Classification
Marée, Raphaël ULg; Geurts, Pierre ULg; Piater, Justus ULg et al

in Proceedings of the IEEE International Conference on Computer Vision and Pattern Recognition (CVPR 2005) (2005)

We present a novel, generic image classification method based on a recent machine learning algorithm (ensembles of extremely randomized decision trees). Images are classified using randomly extracted ... [more ▼]

We present a novel, generic image classification method based on a recent machine learning algorithm (ensembles of extremely randomized decision trees). Images are classified using randomly extracted subwindows that are suitably normalized to yield robustness to certain image transformations. Our method is evaluated on four very different, publicly available datasets (COIL-100, ZuBuD, ETH-80, WANG). Our results show that our automatic approach is generic and robust to illumination, scale, and viewpoint changes. An extension of the method is proposed to improve its robustness with respect to rotation changes. [less ▲]

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See detailClassification automatique d'images par arbres de d́ecision
Marée, Raphaël ULg

Doctoral thesis (2005)

The work presented in this thesis is motivated by the problem of automatic image classification. Image classification methods seek to automatically classify previously unseen images using databases of ... [more ▼]

The work presented in this thesis is motivated by the problem of automatic image classification. Image classification methods seek to automatically classify previously unseen images using databases of labeled images provided by human experts. The main contribution of this thesis is a novel approach for image classification that has been shown to perform well on a variety of tasks. It uses some recent machine learning algorithms based on ensembles of decision trees that we applied directly on pixel values. We combine it with techniques of random extraction and transformation of subwindows from images so as to improve robustness to certain image transformations. The method has been evaluated on 7 publicly available datasets corresponding to various image classification tasks: recognition of handwritten digits, faces, 3D objects, textures, buildings, themes, or landscapes. Some of these datasets contain images representing widely varying conditions: occlusions, cluttered background, illumination, viewpoint, orientation, and scale changes. The accuracy of our method is generally comparable with the state of the art and it is particularly attractive in terms of computational efficiency. [less ▲]

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See detailDecision Trees and Random Subwindows for Object Recognition
Marée, Raphaël ULg; Geurts, Pierre ULg; Piater, Justus ULg et al

in ICML workshop on Machine Learning Techniques for Processing Multimedia Content (MLMM2005) (2005)

In this paper, we compare five tree-based machine learning methods within a recent generic image classification framework based on random extraction and classification of subwindows. We evaluate them on ... [more ▼]

In this paper, we compare five tree-based machine learning methods within a recent generic image classification framework based on random extraction and classification of subwindows. We evaluate them on three publicly available object recognition datasets (COIL-100, ETH-80, and ZuBuD). Our comparison shows that this general and conceptually simple framework yields good results when combined with ensemble of decision trees, especially when using Tree Boosting or Extra-Trees. The latter is also particularly attractive in terms of computational efficiency. [less ▲]

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See detailAdvanced particle characterization for improved understanding of cold spray coating quality
Pirard, Eric ULg; Campana, Florent; Janssen, Jean-Pierre

in Pawlowski, Lech (Ed.) 2e Rencontres Int. Projection Thermique (2005)

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See detailRobustness of Planar Shape Descriptors of Particles
Pirard, Eric ULg; Dislaire, Godefroid

in Chung, C.-F. (Ed.) Proceedings Mathematical Geology Congress (2005)

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