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See detailControlled synthesis of fluorinated copolymers via cobalt-mediated radical copolymerization of perfluorohexylethylene and vinyl acetate
Demarteau, Jérémy ULg; Améduri, Bruno; Ladmiral, Vincent et al

in Macromolecules (2017), 50(10), 3750-3760

Designing novel polyfluoropolymer architectures is attractive for the development of new applications, such as advanced coatings, purification membranes, or materials for energy. Nevertheless, controlling ... [more ▼]

Designing novel polyfluoropolymer architectures is attractive for the development of new applications, such as advanced coatings, purification membranes, or materials for energy. Nevertheless, controlling the radical polymerization of fluoroalkenes is very challenging due to the high reactivity of the propagating fluorinated macroradicals. This study aims at exploring the controlled copolymerization of perfluoro- hexylethylene (PFHE) and vinyl acetate (VAc) in order to prepare a range of well-defined statistical poly(PFHE-stat-VAc) copolymers with different compositions. Cobalt-mediated radical polymerization demonstrated to be active at 40 °C starting from an alkylcobalt(III) initiator, and copolymers with a fluorinated monomer content as high as ca. 80 wt % were successfully prepared. Reactivity ratios were determined to be rVAc = 0.18 and rPFHE = 0 at 40 °C and emphasized a clear tendency for alternation. Unprecedented PFHE/VAc containing block copolymers were also prepared via a single-step approach or through sequential copolymerizations. Finally, hydrolysis of the pendant ester groups of these copolymers led to the corresponding fluorinated copolymers bearing vinyl alcohol (VOH). A preliminary solution behavior study, carried out by dynamic light scattering and transmission electron microscopy on block copolymers composed of PFHE and VAc or VOH units, evidenced a marked amphiphilicity of the copolymer composed of an extremely hydrophobic PFHE block associated with a highly hydrophilic PVOH segment. [less ▲]

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See detailCis-perturbation of cancer drivers by the HTLV-1/BLV proviruses is an early determinant of leukemogenesis
Rosewick, Nicolas; Durkin, Keith ULg; Artesi, Maria ULg et al

in Nature Communications (2017), 8

Detailed reference viewed: 37 (5 ULg)
See detailStudy of volatile organic compounds active against barley pathogens
De Clerck, Caroline ULg; Kaddes, Amine ULg; Fiers, Marie et al

Conference (2017, May 23)

Detailed reference viewed: 27 (2 ULg)
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See detailÉvaluer les performances des étudiants à l’Université
Detroz, Pascal ULg

Scientific conference (2017, May 23)

Évaluer des étudiants à l’université ou en haute école est une lourde responsabilité. À travers les notes distribuées, ce sont des rêves, des aspirations, un parcours universitaire, une vie ... [more ▼]

Évaluer des étudiants à l’université ou en haute école est une lourde responsabilité. À travers les notes distribuées, ce sont des rêves, des aspirations, un parcours universitaire, une vie professionnelle qui se constituent ou qui, dans certains cas plus négatifs, sont altérés ou détruits. L’édumétrie s’est, depuis plus de 70 ans, intéressée à la qualité des examens et des épreuves scolaires. Avec une conclusion redondante et sans concession : les biais dans la mesure récoltée, autrement dit dans le score attribué aux étudiants, sont nombreux et variés et la part d’erreur y est signifiante. Il y a donc des enjeux sociaux importants - d’équité notamment - à proposer des dispositifs d’évaluation robustes reflétant avec exactitude les capacités réelles des étudiants. Ces dernières années, le travail des évaluateurs s’est considérablement complexifié. L’enseignement universitaire a subi une profonde mutation. Sous l’impulsion d’exigences sociales nouvelles, un nouveau vocable s’est érigé en mantra dans nos institutions. Qu’ils s’agissent de compétences, de performances complexes, de soft skills, d’apprentissages authentiques, tous ces concepts ont pour point commun de viser un apprentissage holistique, contextualisé, intégré, multidisciplinaire. Toutes ces évolutions, souvent très pertinentes, se confrontent toutefois aujourd’hui aux limites de nos connaissances dans le domaine de l’évaluation. Certes les modèles de l’évaluation changent peu à peu. Dans les écrits, la focale porte aujourd’hui sur une évaluation porteuse de sens, émancipatrice, axée sur une rétroaction favorisant les apprentissages, partenariale, prenant en compte la complexité des apprentissages visés par l’enseignement. C’est une évolution saine et utile. Mais dans le contexte de l’enseignement supérieur, dans lequel l’avenir des étudiants dépend de la note finale, on peut s’inquiéter en observant que ces modèles en gestation se structurent sans préoccupation particulière quant à la qualité de la mesure. Autour de ces thématiques, nous proposerons un modèle structurant permettant d’augmenter la qualité des dispositifs d’évaluation, y compris dans ces contextes émergents. [less ▲]

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See detailCorrection de questions à réponses ouvertes: le logiciel SQORE
Crahay, Vinciane ULg; Bonnet, Pierre ULg

Conference (2017, May 23)

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See detailLaccase detoxification of lignocellulose hydrolysate
Cornet, Iris; Soti, Valentin; Richel, Aurore ULg et al

Poster (2017, May 22)

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See detailDEVELOPPEMENT D’UN MODELE DE SYSTEME DE CLIMATISATION AUTOMOBILE MULTI-EVAPORATEURS
Gillet, Thomas ULg; Gendebien, Samuel ULg; Lemort, Vincent ULg et al

Conference (2017, May 22)

La modélisation numérique d’un climatiseur d’automobile multi-évaporateurs, composé de deux évaporateurs et d’un refroidisseur d’eau, a été réalisée à l’aide du logiciel LMS Imagine.Lab Amesim® 1D avec le ... [more ▼]

La modélisation numérique d’un climatiseur d’automobile multi-évaporateurs, composé de deux évaporateurs et d’un refroidisseur d’eau, a été réalisée à l’aide du logiciel LMS Imagine.Lab Amesim® 1D avec le fluide frigorigène R-134a. Un banc d’essai capable de reproduire les conditions extérieures d’un climatiseur automobile a été conçu afin de tester l’architecture de cette machine multi-évaporateurs avec le fluide frigorigène R-1234yf. Les bilans thermiques des premiers résultats expérimentaux sont analysés et présentés. Afin d’illustrer la complexité du contrôle d’une telle architecture en régime dynamique, l’activation d’une vanne électromagnétique dans la boucle batterie du banc d’essais est présentée. Enfin, une perturbation de type échelon a été générée dans le modèle numérique afin de vérifier si les phénomènes transitoires observés expérimentalement sont reproduits. [less ▲]

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See detailPuzzling Out Synaptic Vesicle 2 Family Members Functions
Bartholomé, Odile ULg; Van Den Ackerveken, Priscilla ULg; Sanchez Gil, Judit ULg et al

in Frontiers in Molecular Neuroscience (2017)

Detailed reference viewed: 4 (1 ULg)
See detailUnprecendeted fluoroalkene-based copolymers through cobalt-mediated radical polymerization
Demarteau, Jérémy ULg; Ameduri, Bruno; Ladmiral, Vincent et al

Poster (2017, May 22)

The precision design of fluorinated copolymers is challenging but also attractive for future developments in a wide range of applications involving fluoropolymers, such as advanced coatings or ... [more ▼]

The precision design of fluorinated copolymers is challenging but also attractive for future developments in a wide range of applications involving fluoropolymers, such as advanced coatings or purification membranes. In particular, controlling the radical polymerization of fluoroalkenes remains extremely difficult because of the high reactivity of these monomers due to the lack of resonance stabilizing group on their double bond. Herein, Cobalt-Mediated Radical Polymerization (CMRP) was used to efficiently control the bulk copolymerization of perfluorohexylethylene (PFHE) and vinyl acetate (VAc). Well-defined statistical poly(PFHE-stat-VAc) copolymers with different compositions (0 < FPFHE < 0.5) were obtained accordingly. In some cases, fluorinated monomer content as high as 80 % by weight were achieved. Reactivity ratios were determined (rVAc = 0.18 and rPFHE = 0) and emphasized a clear tendency for alternation. Single step approach and sequential polymerization were assessed for the synthesis of novel PFHE/VAc block copolymers. Finally, the acidic hydrolysis of the pendant ester groups of these block copolymers led to the formation of novel highly amphiphilic macromolecules bearing a PVOH hydrophilic segment and a hydrophobic PFHE-based block. [less ▲]

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See detailProtein encapsulation into nanostructured CaCO3 microparticles templated by PEO-b-polyphosphoester using a supercritical CO2 process
Ergül, Zeynep ULg; Debuigne, Antoine ULg; Calvignac, Brice et al

Poster (2017, May 22)

The use of calcium carbonate microparticles is becoming more and more attractive in biomedical applications as proteins carriers for their controlled delivery in the body. We investigate the protein ... [more ▼]

The use of calcium carbonate microparticles is becoming more and more attractive in biomedical applications as proteins carriers for their controlled delivery in the body. We investigate the protein encapsulation by in situ precipitation of CaCO3 particles prepared by a process based on supercritical CO2 and using a new type of degradable well-defined double hydrophilic block copolymer composed of poly(ethylene oxide) and polyphosphoester block with an affinity for calcium like poly(phosphotriester)s bearing pendent carboxylic acids on each repeating monomer unit which evidenced an efficient structure for templating the formation of CaCO3 leading to unprecedented small-sized particles. Lysozyme was chosen as a model for therapeutic protein for its availability and ease of detection. It was found that by this green process, loading into the CaCO3 microparticles with a diameter about 2 μm can be obtained as determined by scanning electron microscopy. A protein loading up to 6.5% active lysozyme was measured by a specific bioassay (Micrococcus lysodeikticus). By encapsulating fluorescent-labelled lysozyme (lysozyme-FITC), the confocal microscopy images confirmed its encapsulation and suggested a core–shell distribution of lysozyme into CaCO3. [less ▲]

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See detailSynthesis of cross-linked P(HEMA) particles in supercritical carbon dioxide for protein delivery
Parilti, Rahmet ULg; Howdle, Steven M.; Jérôme, Christine ULg

Poster (2017, May 22)

This project aims to develop a novel one-pot strategy to obtain well-defined cross-linked particles able to carry peptides/proteins in their core, as along with targeting and/or imaging agents on their ... [more ▼]

This project aims to develop a novel one-pot strategy to obtain well-defined cross-linked particles able to carry peptides/proteins in their core, as along with targeting and/or imaging agents on their surface. In addition to this objective, polymerisations will be carried out in supercritical carbon dioxide (scCO2), which confers environmentally benign features to the process. Here, we investigate the feasibility of free radical dispersion polymerizations of 2-hydroxyethyl methacrylate (HEMA) in scCO2. In order to ensure the successful dispersion in scCO2 novel diblock CO2-philic surfactants are employed. These diblock surfactants are formed from two different segments, a CO2-phobic block which has an affinity to the growing particles and a second CO2-philic block that ensures surfactant solubility. [less ▲]

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See detailPERFORMANCES D’UNE MINI POMPE À CHALEUR RÉVERSIBLE FONCTIONNANT SUR L’AIR EXTRAIT : ÉTUDE NUMERIQUE ET EXPERIMENTALE
Ransy, Frédéric ULg; Gendebien, Samuel ULg; Lemort, Vincent ULg

Poster (2017, May 22)

La majeure partie de la consommation d’énergie des immeubles à appartement dits « basse énergie » est liée à la production d’eau chaude sanitaire et aux pertes par ventilation. De plus, ces immeubles sont ... [more ▼]

La majeure partie de la consommation d’énergie des immeubles à appartement dits « basse énergie » est liée à la production d’eau chaude sanitaire et aux pertes par ventilation. De plus, ces immeubles sont soumis à un risque de surchauffe non négligeable en été. Afin de minimiser leur consommation d’énergie, les systèmes HVAC utilisés dans ces bâtiments se doivent d’être performants et multitâches. Dans cette optique, l’Université de Liège teste actuellement une mini-pompe à chaleur réversible sur air extrait. Cet article présente les résultats expérimentaux obtenus en laboratoire et démontre quelles sont les variables qui influencent les performances de cette machine. Un modèle polynomial est également proposé. [less ▲]

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See detailMerging CO2 transformation and utilization with renewable bio-resources: a step forward to a double vision of sustainable chemistry
Grignard, Bruno ULg; Poussard, Loïc; Raquez, Jean-Marie et al

Conference (2017, May 22)

Valorizing waste CO2 as a cheap, inexhaustible and renewable C1 feedstock is an early stage technology with strong innovation potential that imposes itself as a strategic driver for developing future low ... [more ▼]

Valorizing waste CO2 as a cheap, inexhaustible and renewable C1 feedstock is an early stage technology with strong innovation potential that imposes itself as a strategic driver for developing future low carbon footprints materials. Beside its use as raw chemical, the “physical” valorization of CO2 in a series of industrial cost-efficient processes will also accelerate the development of a low carbon economy and support the elaboration of a global low carbon vision scheme. The synergistic and paradigm-transforming holistic project we propose perfectly illustrates these concepts by encompassing a “cradle” to “grave” vision, i.e. from the products conception from CO2 and bio-resources to their production and processing through sustainable processes compatible with existing industrial relevant infrastructures. It focuses on the elaboration of sustainable isocyanate-free polyurethane foams with promising thermal insulation properties. By its objectives, this study also proposes an ideal alternative to the conventional synthesis of PUs and a practical answer to the challenge the PU sector is facing due to changes in the REACH regulations limiting the use of isocyanates. The success of the project relies on 3 key steps involving: i) The synthesis of bio- and CO2-sourced cyclic carbonates monomers: Due to the low reactivity of CO2 versus epoxides, addition of catalysts is necessary. To overcome this limitation, we developed a new highly-efficient bicomponent homogeneous organocatalyst that showed unexpected activity for the fast (within a few minutes) and selective addition of CO2 onto model epoxides and epoxidized vegetable oil under solvent-free and mild experimental conditions at the multiKg scale. The use of this powerful dual organocatalyst was further extended to the first organocatalytic coupling of CO2 with less reactive oxetanes to produce hydroxyl telechelic oligocarbonate entering the synthesis of CO2-sourced conventional PUs. - The synthesis of sustainable bio- and CO2- sourced isocyanates-free polyurethanes (NIPU): Sustainable NIPUs were produced by step-growth polymerization between the so-produced bio- and CO2-sourced cyclic carbonates and biosourced amino-telechelic comonomers derived from linseed fatty acids according to a process compatible with existing industrial infrastructures (extrusion). - The foaming of NIPUs: Sustainable foams with thermal insulation were produced by the supercritical CO2 assisted foaming technology. Due to its solubility in polymers, CO2 can replace conventional flammable VOCs and ozone depletion physical blowing agents as hydro- or fluorocarbons exhibiting long atmospheric life-time and/or mean global warming potential 2800 higher than CO2. By finely choosing the CO2 impregnation and the foaming conditions, low density microcellular NIPU foams with a thermal conductivity as low as 0.050 Wm-1K-1 were produced. Our study shows that CO2 is not only sequestered in the material for long-term application, but is also valorized as a blowing agent in the production of sustainable thermally insulating NIPU foams. Such low carbon footprints materials will contribute to energy conservation and savings by reducing CO2 emissions. [less ▲]

Detailed reference viewed: 43 (3 ULg)
See detailFunctional emulsion-templated porous polymers by macromolecular surfactant anchoring strategies
Mathieu, Kevin ULg; Jérôme, Christine ULg; Debuigne, Antoine ULg

Poster (2017, May 22)

Macroporous polymer monoliths with interconnected structures have attracted considerable interest in the fields of supported catalysis, chromatography, water purification, etc. A popular and ... [more ▼]

Macroporous polymer monoliths with interconnected structures have attracted considerable interest in the fields of supported catalysis, chromatography, water purification, etc. A popular and straightforward synthesis approach for such open-cell polymers is based on the polymerization of high internal phase emulsion (HIPE). Advanced functional polyHIPEs were also produced via different post-modification strategies but the latter often consists in tedious multi-step processes. This communication aims at reporting an efficient one-pot macromolecular surfactant-assisted method for the simultaneous synthesis and chemical functionalization of macroporous polyHIPEs. Briefly, amphiphilic block copolymers prepared by nitroxide-mediated radical polymerization (NMP) or reversible addition-fragmentation chain transfer (RAFT) were used as HIPE stabilizers and grafted at the surface of the walls of polyHIPE during the polymerization process. The impact of the controlled radical polymerization mechanism on the porous structure, openness and functionalization of the monoliths will be discussed. This strategy was also implemented with alkyne-terminated copolymers in order to decorate the surface of the polyHIPE’s cavities with “clickable” moieties which broadens the scope of functional macroporous polymers. [less ▲]

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See detailPerineuronal nets and song learning-related neuroplasticity in the songbird brain
Cornez, Gilles ULg; Jonckers, Elisabeth; Schevchouk, Olesya et al

Conference (2017, May 22)

Perineuronal nets (PNN) are aggregations of extracellular matrix components surrounding the soma of some neurons, mainly GABAergic interneurons expressing the calcium binding protein parvalbumin (PV+). In ... [more ▼]

Perineuronal nets (PNN) are aggregations of extracellular matrix components surrounding the soma of some neurons, mainly GABAergic interneurons expressing the calcium binding protein parvalbumin (PV+). In mammals, the development of PNN limits synaptogenesis around PV+ neurons and PNN have been validated as a marker characterizing the end of critical periods for visual learning. In songbirds, song learning is limited to critical periods during ontogeny in close-ended learners such as zebra finches and to specific phases of the annual cycle in open-ended learners such as canaries that are able to modify their song seasonally. Sensitive periods for song learning are associated with neuroplasticity including morphological changes due to neurogenesis and synaptic reorganization in the song control nuclei during development and adult seasonal song modifications. The hormonal control of developmental and seasonal neuroplasticity is well documented in songbirds but little is known about the possible regulation of sensitive periods for vocal learning by PNN. First, to explore the expression of PNN throughout the development, we used zebra finches brains collected at different key ages in the song learning process (10, 20, 30, 40, 50, 60, 90, 120 days post-hatch, dph) and we quantified PNN expression and their colocalization around PV+ interneurons. The number of PNN and the % of PNN around PV+ interneurons increased progressively during developmental song learning in 3 of the main song control nuclei (HVC, RA and Area X). Moreover, we confirmed that females that never sing have fewer PNN than males in HVC and RA, two song nuclei involved in song production, at all ages after the peak in PNN numbers seen in males between 50 and 90 dph. Secondly we used adult male and female canaries (in 2 different experiments) treated with a subcutaneous implant filled with testosterone or left empty in control subjects to mimic what happens in the spring when the seasonal modification of the song ends and the song crystallizes. Testosterone significantly increased the number of PNN in the main song control nuclei in both sexes. Together these data suggest that increased expression of PNN in the songbird brain might limit neuroplasticity at the end of developmental and seasonal vocal learning [less ▲]

Detailed reference viewed: 36 (2 ULg)