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See detailFoot identification from digital 3D models of lion tracks and paws
Marchal, Antoine ULg; Lejeune, Philippe ULg; De Bruyn, Nico

Conference (2016, March 15)

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See detailStructural basis for recognition of histone H3K36me3 nucleosome by human de novo DNA methyltransferases 3A and 3B
Rondelet, Grégoire; Dal Maso, Thomas; Willems, Luc ULg et al

in Journal of Structural Biology (2016), 194

DNA methylation is an important epigenetic modification involved in chromatin organization and gene expression. The function of DNA methylation depends on cell context and is correlated with histone ... [more ▼]

DNA methylation is an important epigenetic modification involved in chromatin organization and gene expression. The function of DNA methylation depends on cell context and is correlated with histone modification patterns. In particular, trimethylation of Lys36 on histone H3 tail (H3K36me3) is associated with DNA methylation and elongation phase of transcription. PWWP domains of the de novo DNA methyltransferases DNMT3A and DNMT3B read this epigenetic mark to guide DNA methylation. Here we report the first crystal structure of the DNMT3B PWWP domain–H3K36me3 complex. Based on this structure, we propose a model of the DNMT3A PWWP domain–H3K36me3 complex and build a model of DNMT3A (PWWP-ADD-CD) in a nucleosomal context. The trimethylated side chain of Lys36 (H3K36me3) is inserted into an aromatic cage similar to the ‘‘Royal” superfamily domains known to bind methylated histones. A key interaction between trimethylated Lys36 and a conserved water molecule stabilized by Ser270 explains the lack of affinity of mutated DNMT3B (S270P) for the H3K36me3 epigenetic mark in the ICF (Immunodeficiency, Centromeric instability and Facial abnormalities) syndrome. The model of the DNMT3A-DNMT3L heterotetramer in complex with a dinucleosome highlights the mechanism for recognition of nucleosome by DNMT3s and explains the periodicity of de novo DNA methylation. [less ▲]

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See detailDEVELOPMENT OF PHARMACOLOGICAL TOOLS FOR THE IDENTIFICATION OF G PROTEIN-COUPLED RECEPTORS LIGANDS
Gilissen, Julie ULg

Doctoral thesis (2016)

G protein-coupled receptors (GPCRs) represent the protein family most successfully targeted for treating human diseases. They couple to G proteins to mobilize second messenger pathways that lead to ... [more ▼]

G protein-coupled receptors (GPCRs) represent the protein family most successfully targeted for treating human diseases. They couple to G proteins to mobilize second messenger pathways that lead to cellular responses and ultimately to physiological changes. However many are poorly characterized with few ligands reported or remain completely orphans. Therefore, there is a growing need for screening-compatible and sensitive assays in order to identify new ligands. The present project aims at developing pharmacological tools to characterize the pharmacology and physiology of GPCRs. Our approach rely on i) development of receptor models and assays for the identification of ligands, ii) screening of chemical and virtual small molecules libraries and iii) analysis of structure-activity relationships study of active molecules. The project has been divided in two parts. To set-up assays for the evaluation of GPCRs activation, we selected the understudied succinate receptor 1 (SUCNR1) that is proposed to affect cellular metabolism and pathophysiology of diseases in multiple organs. Nevertheless the receptor has never been validated as a drug target because very few ligands have been described. So, developing pharmacological tools for SUCNR1 remains of great interest in therapeutic drug discovery. First, we have started by examining SUCNR1 signaling pathways in HEK293 cells. Our investigations have highlighted the efficient coupling to Gαi and thus the negative modulation of intracellular cAMP levels. Consequently we have implemented an assay sensitive to cAMP variations to identify ligands able to induce SUCNR1 activation. However, an important drawback to track agonists for Gαi-coupled receptors is the mandatory stimulation of cAMP levels. Inducers such as forskolin must be used and are sources of variations and errors. In order to avoid these artifacts we have set-up and validated a cAMP-inducer free method based on the GloSensor biosensor. This real time assay was amenable to high-throughput screening for the detection of Gαi-coupled receptors agonists. The strategy monitoring basal cAMP levels compared to the stimulated cAMP levels allowed to decrease recording time and artifcats from forskolin use, leading to the identification of fewer false positives and unidentified false negatives. Although both methods found agonists in the chemical library screened, no active new scaffolds on SUCNR1 were discovered. We infer that this method could facilitate the study and screening of Gαi-coupled receptors for active ligands. Secondly, given the interesting potential of SUCNR1 for promising therapeutic advances, we have carried out the study of the receptor interaction with its natural ligand, succinate. We have optimized the previous three-dimensional model for SUCNR1 binding pocket by means of more detailed structure-activity relationships study of succinate related molecules. The study of structure-activity relationships performed by Pierre Geubelle, in parallel to this work, allowed the deduction of the structural elements required to be active on SUCNR1. Thus we have defined a pharmacophore for activity on the receptor and subsequently evaluated various cycloalkanes. With our cAMP assay, Pierre Geubelle has highlighted the (1R, 2S)-1,2-cyclopropanedicarboxylate to be able to activate SUCNR1. We confirmed the activity of this compound on SUCNR1 capacity to recruit arrestin 3 and determined the pharmacological properties of this new ligand as SUCNR1 agonist, in vitro and in vivo. To confirm our in vitro results, we have also assessed the hypertensive properties of this cyclic analogue. Intravenous addition at the dose of 0.1 mg.kg-1 in rats has been demonstrated to increase blood pressure in the same range as succinate. Consequently we have demonstrated that (1R, 2S)-1,2-cyclopropanedicarboxylate could be regarded as an original synthetic full agonist for SUCNR1. In addition, the pharmacophore for SUCNR1 should help to generate synthetic compounds characterized by an increased potency and/or efficacy compared to succinate. [less ▲]

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See detailThe transition to conservation agriculture : an insularization process towards sustainability
Vankeerberghen, Audrey ULg; Stassart, Pierre M ULg

in International Journal of Agricultural Sustainability (2016)

Part of the Sustainability Transition Studies, this work addresses the question of the relationship between niches and regimes by examining the transition to conservation agriculture. It seeks to ... [more ▼]

Part of the Sustainability Transition Studies, this work addresses the question of the relationship between niches and regimes by examining the transition to conservation agriculture. It seeks to understand how farmers' transition to conservation agriculture can contribute to a better understanding of the transition of agro-food systems towards sustainability. Based on an analysis of farmers' trajectories in the Walloon region in Belgium, the paper develops the notion of insularization in order to characterize the emergence of conservation agriculture as a niche that is a dynamic process, growing from within and progressively detaching itself from the conventional agricultural regime. The analysis of farmers' transition shows how, after an initial phase of destabilization of the conventional ploughing regime, learning and experiencing processes can lead to a transformation in soil and soil quality management perceptions. Our hypothesis is that this cognitive transformation constitutes a tipping point in the insularization process because of its effects on agricultural practices, which increase the detachment of conservation agriculture from the regime and thus embed the irreversibility and sustainability of the transition. The term insularization is used to describe an ecologization pathway of agricultural practices endogenous to the regime that can not only lead to adaptive changes on the periphery of the system, but might also induce a deep and systemic transformation of conventional agricultural practices. [less ▲]

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See detailC'est la faute à l'Europe !
Grandjean, Geoffrey ULg

Conference given outside the academic context (2016)

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See detailGel Beads to Investigate Sedimentation
Leleu, David ULg; Pfennig, Andreas ULg

Scientific conference (2016, March 14)

Separation of liquid-liquid dispersions with multiple phases involves different interactions between the different dispersed species present in the system, which makes it difficult to predict e.g. the ... [more ▼]

Separation of liquid-liquid dispersions with multiple phases involves different interactions between the different dispersed species present in the system, which makes it difficult to predict e.g. the separation behaviour. Nevertheless such systems are relevant in chemical engineering e.g. for systems involving gas bubbles and simultaneously solid particles like in a fermentation broth. Models for describing the sedimentation behaviour as a basis for settler design are available in principle but have not been systematically validated for variation in size-distribution and e.g. density differences between the various species in the system. Thus, to design technical separation equipment, the separation process has to be better understood, which requires the study of the sedimentation as a first step. This project is focused on the interactions which may occur between each species during the sedimentation e.g. the effect on sedimentation of descending particles when they meet ascending drops. However, a proper study of the sedimentation with fluid phases is difficult due to other phenomena occurring simultaneously, e.g. coalescence. To overcome this issue, the use of gel beads is proposed, which due to their solid interface cannot coalesce. In addition, it is easy to define their parameters which are the density, the hardness and the size distribution. Besides, they can also be preserved during an extended period of time, experiments can thus be reproduced many times with identical beads. During the project, gel beads are designed with different particle size distributions and with different densities. Different batches of the produced gel beads will be mixed to simulate systems with different dispersed phases discriminated via density and different size distributions. With these multiple dispersed phases Experiments will be performed in a settling cell in order to evaluate the overall sedimentation velocity at certain hold up. Simultaneously a new method for measurement of local hold-up profile in the dispersion is tested, which allows hold-up measurement even in opaque systems. Finally sedimentation models found in the literature are compared and adapted to experimental results for predict the sedimentation of systems which involve different dispersed phases. In the presentation the new hold-up measurement will be presented together with an error analysis, experiments on the sedimentation of multiple dispersed phases and the model evaluation will be presented. [less ▲]

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See detailCaractérisation et tests de traitement des déchets ménagers et boues de vidange par voie anaérobie et compostage pour la ville de Kinshas
Mindele Ukondalemba, Léonard ULg

Doctoral thesis (2016)

Dans les pays en développement (PED) en général et en République Démocratique du Congo en particulier, la problématique de l’assainissement (eaux usées et des déchets solides) constitue un enjeu majeur ... [more ▼]

Dans les pays en développement (PED) en général et en République Démocratique du Congo en particulier, la problématique de l’assainissement (eaux usées et des déchets solides) constitue un enjeu majeur pour les spécialistes et les autorités locales. Cette thèse a comme objectif général de faire une évaluation de l’état des lieux et de dégager des pistes possibles de traitements des déchets solides et liquides en vue de protéger les populations et de s’orienter vers des traitements qui respectent au mieux les principes du développement durable. Pour réaliser cet objectif, il a été question de caractériser les déchets municipaux solides, spécialement des déchets ménagers, par une méthode de caractérisation rapide, simple et peu couteuse. Pour ce qui concerne la gestion des eaux usées, spécialement les boues de vidange provenant de l’assainissement non collectif (ANC), par une méthode sociologique mobilisant des techniques d'enquêtes et d'observation sur site, qui a permis de bien comprendre les pratiques d'assainissement non collectif sur terrain dans le contexte de la République démocratique du Congo ; enfin d’un essai de traitement par une digestion anaérobie (ou co-digestion anaérobie) des déchets suivi du compostage (ou co-compostage).Parmi les modes de traitement de déchets, la digestion anaérobie paraît être une option attrayante pour la dégradation des déchets ménagers fermentescibles en produits utiles tels que le biogaz et le compost de haute qualité. De ce fait, nous avons mené une étude expérimentale comparative entre la digestion anaérobie des déchets ménagers fermentescibles uniquement et la co-digestion anaérobie des déchets ménagers fermentescibles et de boues de vidange de fosse septique. L’expérience a été conduite dans deux cuves de 80 litres. La digestion et la co-digestion anaérobies se sont déroulées à la température de 25°C et en deux étapes, de sorte que la première étape dans la cuve de 80 L, s’arrête à l'acidogenèse et que la deuxième étape se passe dans un autre digesteur de 10 L allant de l’acétogenèse à la méthanogenèse. Les résultats ont montré que 1,3 Nm3 de méthane sont produits à partir de la digestion anaérobie des déchets uniquement et 1,8 Nm3 de méthane sont produits à partir de la co-digestion des déchets et des boues de vidange, confirmant l’intérêt de la co-digestion.Les résultats préliminaires trouvés sont encourageants, notamment en matière de gain detemps dans la durée du processus. Le procédé a entre autres avantages de limiter la manipulation du déchet en cours de traitement et de fournir à la fin deux produits directement valorisables : le compost et le méthane. Bien entendu ces résultats préliminaires devront être validés par des essais à une échelle un peu plus grande avant de proposer de passer à des projets en vraie grandeur. Ainsi nous espérons que ce travail pourra contribuer à la relance des digesteurs anaérobies pour favoriser les énergies renouvelables tels que prôné ce dernier temps par la COP21 et ainsi éviter la déforestation intempestives des nos forets. Mots clés : assainissement non collectif, déchets solides fermentescibles, boue de vidange, co-digestion anaérobie, indicateur d'assainissement, digestion anaérobie, compost. [less ▲]

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See detail"Car telle est notre foi par laquelle vous serez sauvés". Les Carolingiens et la défense de l’orthodoxie
Close, Florence ULg

Scientific conference (2016, March 14)

Dès 796, Charlemagne ne se dit plus seulement rector et defensor ecclesiae mais également praedicator. Partant de ce constat, bien établi par quelques solides recherches récentes, Florence Close pose la ... [more ▼]

Dès 796, Charlemagne ne se dit plus seulement rector et defensor ecclesiae mais également praedicator. Partant de ce constat, bien établi par quelques solides recherches récentes, Florence Close pose la question du cheminement qui a amené le fils de Pépin le Bref à affiner au fil des décennies l’aspect religieux de la mission royale franque au point de se considérer comme le défenseur de l’orthodoxie en Occident. [less ▲]

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See detailOpening risk gouvernance with a vigilance system: lessons learned from the Blue Tongue Virus outbreak in 2006
Fallon, Catherine ULg

Conference (2016, March 14)

This contribution results from a field research by a multidisciplinary group of veterinary and political scientists and gives an analyses of the transformations of an epidemiosurveillance governance ... [more ▼]

This contribution results from a field research by a multidisciplinary group of veterinary and political scientists and gives an analyses of the transformations of an epidemiosurveillance governance system dedicated to animal diseases, when confronted to new emerging threats in the wake of global changes (Fallon et al., in Vertigo 12(3) 2012) . The research field refers to the emergence of bluetongue virus serotype 8 in 2006 in Belgium and it mobilises the results of a survey based on Delphi method involving relevant public servants and scientists, which showed that most of the means proposed by the authorities are based on the logic of known risk management. However we can identify attempts for renewal and organisational learning, especially with the proposal of a new vigilance system, which allows open discussion and reporting through the decision process. In terms of prevention and anticipation of the adverse event), these changes are intended to accommodate the surveillance system reactivity against uncertain and unforeseen events. We question the problems faced by this transformation and its potential for enriching and reconfiguring the conceptualisation of risk management which is currently dominant in the sector. Finally the article identifies two drivers for change in the governance network : by admitting the persistence of unavoidable cognitive uncertainty and by recognizing the importance for opening up arenas of expert knowledge. [less ▲]

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See detailL’aménagement forestier au Congo engendre-t-il plus de déforestation ?
Karsenty, Alain; Cerutti, P.; Doucet, Jean-Louis ULg et al

E-print/Working paper (2016)

Un article publié dans Land Use Policy début 2016 arrive à la conclusion a priori étonnante que la déforestation serait, au Congo, plus élevée dans les concessions forestières avec des plans d’aménagement ... [more ▼]

Un article publié dans Land Use Policy début 2016 arrive à la conclusion a priori étonnante que la déforestation serait, au Congo, plus élevée dans les concessions forestières avec des plans d’aménagement que dans celles qui n’en ont pas. L’analyse d’évaluation d’impact qui a conduit ces chercheurs à un tel résultat se base sur un appariement de parcelles sélectionnées aléatoirement dans des concessions avec et sans plans d’aménagement. Ces chercheurs indiquent que le réseau de routes forestières plus développé dans les concessions aménagées serait un des facteurs explicatifs. L’autre facteur serait le développement local lié aux cahiers des charges des plans d’aménagement, lequel conduirait à une augmentation de la population dans ces concessions et à une déforestation accrue. Notre groupe d’une vingtaine de chercheurs connaissant bien la problématique de l’aménagement forestier en Afrique centrale s’est penché à son tour sur cette question et a analysé la déforestation au niveau des concessions sur le même intervalle de temps. Nos résultats montrent, cette fois, que la déforestation est moins importante dans les concessions avec un plan d’aménagement que dans les autres. Et si l’on compare à production égale la déforestation dans des concessions avec et sans plan d’aménagement, il apparaît que les UFA aménagées sont environ deux fois plus « efficaces », c’est-à-dire qu’on observe deux fois moins de perte de couvert forestier par mètre-cube produit. Nous en concluons qu’il est nécessaire d’analyser précisément la dynamique des différents facteurs de déforestation, et éviter d’imputer mécaniquement à l’aménagement forestier un rôle excessif dans l’évolution dans un sens ou dans l’autre du taux de déboisement. Enfin, toute évaluation doit rappeler que les effets de l’aménagement forestier doivent être mesurés sur le long terme : l’objectif de l’aménagement est de permettre une mise en valeur forestière durable, en conservant l’essentiel du capital productif pour éviter, autant que possible, la conversion à d’autres usages après les cycles de coupe initiaux. [less ▲]

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See detailGetting on Board but How? Conflicting Perspectives on the Role of the Social Sciences and Humanities in Radiation Protection
Van Oudheusden, Michiel ULg; Rossignol, Nicolas ULg; Perko, Tanja et al

Conference (2016, March 14)

In Europe, science research policy is predicated on the understanding that science and technology (S&T) serve societal needs. Accordingly, European Framework Programs urge scientists and technologists to ... [more ▼]

In Europe, science research policy is predicated on the understanding that science and technology (S&T) serve societal needs. Accordingly, European Framework Programs urge scientists and technologists to give due attention to societal and ethical aspects of S&T, and to engage with social scientists and humanists when doing research and reaching out to society. Starting from these policy prescriptions and from invitations from befriended life scientists to "get on board," we explore the terms of our involvement as social scientists and humanists in a European Joint Program on radiation protection research (EJP-CONCERT). We illuminate recurring tensions between instrumental, normative, and substantive perspectives on the role of the social sciences and humanities (SSH) in radioprotection research and nuclear S&T. Our aim is to shed light on the controversial and contingent nature of integrating SSH into nuclear S&T, as actors articulate divergent assumptions and expectations about SSH and society. These expectations pertain to the value of SSH research for S&T, issues of trust and legitmacy, and different perspectives on risk and uncertainty. By rendering these tensions explicit we seek to probe the implications for SSH of developing a separate SSH Strategic Research Agenda (SRA) within radiation protection research. [less ▲]

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See detailAb initio phonon limited transport
Verstraete, Matthieu ULg

Speech/Talk (2016)

We revisit the thermoelectric (TE) transport properties of two champion materials, PbTe and SnSe, using fully first principles methods. In both cases the performance of the material is due to subtle ... [more ▼]

We revisit the thermoelectric (TE) transport properties of two champion materials, PbTe and SnSe, using fully first principles methods. In both cases the performance of the material is due to subtle combinations of structural effects, scattering, and phase space reduction. In PbTe anharmonic effects are completely opposite to the predicted quasiharmonic evolution of phonon frequencies and to frequently (and incorrectly) cited extrapolations of experiments. This stabilizes the material at high T, but also tends to enhance its thermal conductivity, in a non linear manner, above 600 Kelvin. This explains why PbTe is in practice limited to room temperature applications. SnSe has recently been shown to be the most efficient TE material in bulk form. This is mainly due to a strongly enhanced carrier concentration and electrical conductivity, after going through a phase transition from 600 to 800 K. We calculate the transport coefficients as well as the defect concentrations ab initio, showing excellent agreement with experiment, and elucidating the origin of the double phase transition as well as the new charge carriers. AH Romero, EKU Gross, MJ Verstraete, and O Hellman PRB 91, 214310 (2015) O. Hellman, IA Abrikosov, and SI Simak, PRB 84 180301 (2011) [less ▲]

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See detailRetrieval of HCFC-142b (CH3CClF2) from ground-based high-resolution infrared solar spectra: Atmospheric increase since 1989 and comparison with surface and satellite measurements
Mahieu, Emmanuel ULg; Lejeune, Bernard ULg; Bovy, Benoît ULg et al

in Journal of Quantitative Spectroscopy & Radiative Transfer (2016)

We have developed an approach for retrieving HCFC-142b (CH3CClF2) from ground-based high-resolution infrared solar spectra, using its ν7 band Q branch in the 900–906 cm-1 interval. Interferences by HNO3 ... [more ▼]

We have developed an approach for retrieving HCFC-142b (CH3CClF2) from ground-based high-resolution infrared solar spectra, using its ν7 band Q branch in the 900–906 cm-1 interval. Interferences by HNO3, CO2 and H2O have to be accounted for. Application of this approach to observations recorded within the framework of long-term monitoring activities carried out at the northern mid-latitude, high-altitude Jungfraujoch station in Switzerland (46.5°N, 8.0°E, 3580 m above sea level) has provided a total column times series spanning the 1989 to mid-2015 time period. A fit to the HCFC-142b daily mean total column time series shows a statistically-significant long-term trend of (1.23±0.08×1013 molec cm-2) per year from 2000 to 2010, at the 2-σ confidence level. This corresponds to a significant atmospheric accumulation of (0.94±0.06) ppt (1 ppt=10-12) per year for the mean tropospheric mixing ratio, at the 2−σ confidence level. Over the subsequent time period (2010–2014), we note a significant slowing down in the HCFC-142b buildup. Our ground-based FTIR (Fourier Transform Infrared) results are compared with relevant data sets derived from surface in situ measurements at the Mace Head and Jungfraujoch sites of the AGAGE (Advanced Global Atmospheric Gases Experiment) network and from occultation measurements by the ACE-FTS (Atmospheric Chemistry Experiment-Fourier Transform Spectrometer) instrument on-board the SCISAT satellite. [less ▲]

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See detailJean-Jacques Boissard dit le Bisontin : un antiquaire du XVIe siècle
De Marco, Rosa ULg

Conference given outside the academic context (2016)

Né à Besançon, Jean-Jacques Boissard (1528-1602) arpente l’Europe. En Allemagne, en Prusse, en Italie, en Grèce, il dessine les reliefs antiques et entretient des échanges savants avec les plus grands ... [more ▼]

Né à Besançon, Jean-Jacques Boissard (1528-1602) arpente l’Europe. En Allemagne, en Prusse, en Italie, en Grèce, il dessine les reliefs antiques et entretient des échanges savants avec les plus grands érudits de son temps en partageant la passion archéologique et l’idéal humaniste. La communication approfondira les voyages romains de Boissard, ses rencontres, ses explorations, sa vision de Rome antique et moderne. En parcourant l’œuvre multiforme de l’antiquaire, collectionneur, faussaire, poète, moraliste bisontin, nous montrerons la manière dont l’auteur appréhende l’Antiquité et ses vestiges : données documentaires, mise en scène antiquisante, ou encore signes et reliques d’un passé supérieur. [less ▲]

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See detailAgeism and communication in oncology
Schroyen, Sarah ULg; Adam, Stéphane ULg; Marquet, Manon ULg et al

Poster (2016, March 11)

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See detailSaisir les transformations des espaces politiques par le prisme des instruments de finances publiques
Piron, Damien ULg

Scientific conference (2016, March 11)

Detailed reference viewed: 17 (3 ULg)
See detailVirtual Leodium - Modélisation 3D de la ville de Liège - Etat d’avancement mars 2016
Carré, Cyril ULg

Diverse speeche and writing (2016)

Detailed reference viewed: 21 (5 ULg)