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See detailModelling the mortality of Hylotrupes bajulus (L.) larvae exposed to anoxic treatment for disinfestation of wooden art objects
de Streel, Géraud; Henin, Jean-Marc; Bogaert, Patrick et al

Conference (2016, September 13)

Experiments were conducted to quantify the effect of several variables on the mortality of insects exposed to an anoxic treatment in order to generate a model linking mortality to these variables. This ... [more ▼]

Experiments were conducted to quantify the effect of several variables on the mortality of insects exposed to an anoxic treatment in order to generate a model linking mortality to these variables. This study aims to explore the possible interest of using such a model to determine the characteristics of treatment (especially duration) needed to guarantee insect mortality with a given level of probability. Trials were performed on Hylotrupes bajulus larvae, which is a widespread species known for its high tolerance to anoxic conditions. The studied variables are the initial mass of the larvae, the treatment temperature (21, 30 and 40 °C), the treatment duration (four durations for each temperature tested) and whether the larva is held in wood or in a petri dish (directly exposed to anoxic atmosphere) during the experiment. It was found that, while the last variable is not correlated with mortality, treatment duration and temperature are significantly and positively correlated with it. Larvae with higher body mass were also shown to have a better resistance to the treatment. Based on these results, a model including insect initial mass, treatment temperature and duration, together with the interaction between these two variables, was determined. This relatively simple model appeared to be a useful tool in overcoming the difficulty in defining the modalities for anoxic treatment in order to reach a given level of mortality. [less ▲]

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See detailSynthesis and characterizations of non-isocyanate polyurethane (NIPU) hydrogels
Gennen, Sandro ULg; Grignard, Bruno ULg; Thomassin, Jean-Michel ULg et al

Poster (2016, September 12)

Polyurethane (PU) is on of the most used polymers for the preparation of hydrogels due to its good biocompatibility, biodegradation and excellent mechanical properties. PU hydrogels are found in lot of ... [more ▼]

Polyurethane (PU) is on of the most used polymers for the preparation of hydrogels due to its good biocompatibility, biodegradation and excellent mechanical properties. PU hydrogels are found in lot of applications such as wound dressing, soft contact lenses, drug delivery and scaffolds for tissue engineering. Classicaly, PU is produced by a step-growth polymerization between diols and diisocyanates. However, in order to avoid the use of harmful isocyanates compounds and because of regulations which tend to ban the use of isocyanates, we developed hydrogels based on a non-isocyanate polyurethane (NIPU) chemistry by valorizing CO2-sourced cyclic carbonates and amines. Precisely, NIPU hydrogels were prepared by a solvent-free copolymerization between bifunctional hydrophilic polyethylene glycol cyclic carbonates and diamines in presence of a triamine as a crosslinker, followed by a water swelling of the obtained cross-linked gel. Parameters such as the cross-linking ratio and diamine’s nature were optimized. Different clay contents (cloiste 30B) as nanofiller were dispersed in the ideal cyclic carbonate/diamine/triamine formulation prior polymerization in order to reinforce the compression properties of NIPU hydrogels. Finaly, we were able to prepare NIPU hydrogels with water content up to 80 % and good compression properties using low clay content. [less ▲]

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See detailPolyphosphoester containing amphiphilic block copolymers as drug nanocarriers
Ergül, Zeynep ULg; Vanslambrouck, Stéphanie; Thiry, Justine ULg et al

Poster (2016, September 12)

The design of drug delivery systems often requires biodegradable and biocompatible materials that allow safe retention and controlled release of the drug. In this respect, supramolecularly self-assembled ... [more ▼]

The design of drug delivery systems often requires biodegradable and biocompatible materials that allow safe retention and controlled release of the drug. In this respect, supramolecularly self-assembled amphiphilic block copolymers into spherical micelles are appropriate carriers for poorly soluble drugs. In that framework, we have designed novel functional poly(ethylene oxide)-b-polyphosphoester amphiphilic block copolymers able to cross-linked under UV and degrade in response to a reduction of the pH from neutral conditions. Therefore, an unsaturated alkene side-chain was introduced on the cyclic phosphate monomer according to a one-step reaction followed by its organocatalyzed polymerization initiated by a poly(ethylene oxide) macroinitiator. After self-assembly into water, the micelles were cross-linked by UV irradiation. Then, these cross-linked micelles have been loaded by doxorubicin, i.e. a drug used in cancer therapy. We observed that the doxorubicin loading increased with the number of double bonds on the polyphosphate block of non-cross-linked micelles. This diblock amphiphilic copolymer bearing pendant unsaturations appears thus particularly promising candidate to build micellar drug delivery systems for intravenous injection. [less ▲]

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See detailJoint learning and pruning of decision forests
Begon, Jean-Michel ULg; Joly, Arnaud ULg; Geurts, Pierre ULg

Conference (2016, September 12)

Decision forests such as Random Forests and Extremely randomized trees are state-of-the-art supervised learning methods. Unfortunately, they tend to consume much memory space. In this work, we propose an ... [more ▼]

Decision forests such as Random Forests and Extremely randomized trees are state-of-the-art supervised learning methods. Unfortunately, they tend to consume much memory space. In this work, we propose an alternative algorithm to derive decision forests under heavy memory constraints. We show that under such constraints our method usually outperforms simpler baselines and can even sometimes beat the original forest. [less ▲]

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See detailOverhanging Constraints in Addivitive Manufacturing Using Two Different Tools
Bauduin, Simon ULg; Collet, Maxime ULg; Duysinx, Pierre ULg

Conference (2016, September 12)

Topology optimization is widely used as a design tool for advanced application in mechanical, aerospace and automotive industries. This technique offers an optimal distribution of a predetermined amount ... [more ▼]

Topology optimization is widely used as a design tool for advanced application in mechanical, aerospace and automotive industries. This technique offers an optimal distribution of a predetermined amount of material in a given design space. In the last years, a lot of efforts has been invested into the development of high performance methods such as homogenization, SIMP or BESO. However as the state of the art in manufacturing experiences evolution, a coupling between topology optimization and additive manufacturing is needed. Additive manufacturing has numerous advantages that fits the characteristics of topology optimized designs. It can manufacture highly complex design without high cost increase and furthermore continuous density material of the SIMP method could be manufactured by lattice structures. With all the opportunities given by the additive manufacturing the urge to bind the last one to topology optimization is heavily required. Specific constraints related to manufacturing issues have to be taken into account such as the need of supports structures to ensure a good heat evacuation during the manufacturing process, as well as to hold up overhanging section. Some researches have been done to try to include this constraint in the optimization problem such as Leary and al or Andrew T. Gaynor. However this work focuses on 2 different methods (projection scheme and mechanical approach) to tackle the overhanging problem and compare them . [less ▲]

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See detailOrganocobalt complexes as source of radicals for the controlled polymerization of unconjugated monomers
Demarteau, Jérémy ULg; Cordella, Daniela ULg; Kermagoret, Anthony et al

Poster (2016, September 12)

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See detailETUDE FONCTIONNELLE DES FACTEURS D’ÉPISSAGE SR D’ARABIDOPSIS THALIANA
Stankovic, Nancy ULg

Doctoral thesis (2016)

Dans ce travail, nous avons montré que la protéine RSZ22, est une protéine hautement dynamique. Cette protéine fait partie de la sous-famille des protéines RSZ d’Arabidopsis et est l’homologue de la ... [more ▼]

Dans ce travail, nous avons montré que la protéine RSZ22, est une protéine hautement dynamique. Cette protéine fait partie de la sous-famille des protéines RSZ d’Arabidopsis et est l’homologue de la protéine SRSF7 humaine. Elle possède un domaine RRM, un domaine RS et entre les deux un domaine de liaison au RNA Zn-knuckle de type CCHC. L’utilisation des approches de FRAP (Fluorescence Recovery After Photobleaching) et de FLIP (Fluorescence Loss In Photobleaching) ont permis d’étudier la dynamique de cette protéine mais aussi sa capacité de navette entre le noyau et le cytoplasme comme son homologue humain SRSF7. Ces études ont été réalisées avec RSZ22 fusionnée à la GFP et surexprimée transitoirement dans des cellules foliaires mais aussi en transformation stable chez Arabidopsis (Rausin et al., 2010; Tillemans et al., 2006). Dans cette étude, nous avons montré que RSZ22, comme les protéines de la famille SR, est une protéine navette. Par analyses de FLIP-shuttling nous avons pu établir des cinétiques d'exportation et confirmer que les protéines SR végétales utilisent le récepteur CRM1/XPO1 comme voie d’exportation. Sa mobilité dépend du niveau de phosphorylation et de la concentration en ATP de la cellule. La complémentarité des techniques de surexpression en transformation transitoire et de l’expression stable ayant été démontrée (Rausin et al., 2010), nous nous y sommes référés pour notre étude de dynamique des protéines nucléaires. Nous avons également cherché à évaluer les rôles des domaines d’accrochage au RNA de RSZ22 dans sa localisation et sa dynamique. Par mutagenèse dirigée, nous avons modifié les acides aminés conservés connus pour jouer un rôle dans les interactions avec le RNA (Clery et al., 2008; Hargous et al., 2006; Lunde et al., 2007; Maris et al., 2005; Phelan et al., 2012). Nos résultats montrent que les domaines Zn-knuckle et RRM fonctionnels ne sont pas nécessaires à la localisation nucléaire de la protéine RSZ22, ni à sa localisation en speckles. La dynamique nucléocytoplasmique de la protéine RSZ22 n’est pas altérée par la mutation des motifs Zn-knuckle et RNP1. Cependant, les protéines mutées de RSZ22 répondent différemment aux traitements par la LMB. En effet, celles-ci ne sont plus « retenues » dans le noyau après un tel traitement et continuent d’être exportées vers le cytoplasme. Sachant que la LMB est un inhibiteur spécifique de la voie CRM1/XPO1, ce dernier récepteur est impliqué dans l’exportation des protéines SR en interaction avec le RNA (Williams et al., 2008). Dans la suite des recherches réalisées au sein du laboratoire, nous avons étudié la dynamique nucléo-cytoplasmique des protéines SR, en étudiant la sous-famille SRSF1-like. Chez Arabidopsis thaliana, cette famille se compose des protéines SR34, SR34a, SR34b et SR30 et possède deux domaines RRM et un domaine RS. Comme RSZ22, SR34 et SR34a font la navette entre le noyau et le cytoplasme. Nous formulons ainsi l’hypothèse que comme son homologue humain SRSF1, SR34 pourrait être impliquée dans l’exportation du mRNA vers le cytoplasme. Nous avons analysé les rôles des différents domaines de SR34 par mutagénèse dirigée. Nous avons montré que le domaine RS de la protéine SR34 est nécessaire pour la localisation nucléaire et la stabilité de la protéine. Les motifs de liaison au RNA sont impliqués dans l’exportation de SR34 par la voie CRM1/XPO1. Par la technique du double hybride en levure, une interaction entre SR34 et SR45 a pu être mise en évidence et confirmée par FLIM-FRET (Fluorescence-Lifetime Imaging Microscopy - Fluorescence Resonance Energy Transfert). L’analyse des interactions entre SR45 et les protéines SR34 mutantes montre l’importance des différents domaines de la protéine dans les interactions protéine-protéine. [less ▲]

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See detailChapter 16 - Solar thermal powered Organic Rankine Cycles
Orosz, Matthew; Dickes, Rémi ULg

in Macchi, Ennio; Astolfi, Marco (Eds.) Organic Rankine Cycle (ORC) Power Systems: Technologies and Applications (2016)

Reference chapter about solar-based organic Rankine cycle power systems published in the book "Organic Rankine Cycle (ORC) Power Systems: Technologies and Applications"

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See detailRandom subspace with trees for feature selection under memory constraints
Sutera, Antonio ULg; Châtel, Célia; Louppe, Gilles et al

Conference (2016, September 12)

Detailed reference viewed: 41 (7 ULg)
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See detailMicrostructural design using stress–based topology optimization
Collet, Maxime ULg; Bruggi, Matteo; Noël, Lise ULg et al

Conference (2016, September 12)

New additive manufacturing techniques break the limitations encountered for years when producing components descending from topology optimization. Classical design procedures focus on macro-structural ... [more ▼]

New additive manufacturing techniques break the limitations encountered for years when producing components descending from topology optimization. Classical design procedures focus on macro-structural optimization to sustain given loads but today innovative manufacturing processes allow considering structures exhibiting tailored microstructures, i.e. the well known microstructural design. The practical applications of structures including material design is mainly motivated by the greater performances that can be achieved compared to classical solutions. Microstructural design has been shown a great interest as attested by recent works. However, stress–based topology optimization has not yet been extensively exploited when addressing microstructural design using numerical homogenization though stress constraints is an important feature and have gained in interest in the field of topology optimization. This contribution investigates the problem of material design enforcing stress constraints within periodic microstructures by considering a representative volume element (RVE) subject to prescribed strain fields. The SIMP approach is adopted as material interpolation law while the optimization problems are solved using a sequential convex programming approach. In particular the well known method of moving asymptotes (MMA) is considered. Numerical homogenization is used to assess the effective elastic properties of the microstructures. The Von Mises stress criterion is used to impose the constraints on the stress level. This work discusses the formulation of a well-posed design problem as well as some numerical issues encountered. The developed solution procedure is first validated by comparison against analytical results, e.g. the single inclusion of Vigdergauz microstructure. [less ▲]

Detailed reference viewed: 65 (3 ULg)
See detailPAI Annual Meeting
Ouhib, Farid ULg; Aqil, Abdelhafid ULg; Dirani, Ali et al

Poster (2016, September 12)

Detailed reference viewed: 9 (1 ULg)