References of "Jérôme, Christine"
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See detailUse of response surface methodology for the optimization of the lipase-catalyzed synthesis of mannosyl myristate in pure ionic liquid
Galonde, Nadine ULg; Brostaux, Yves ULg; Richard, Gaetan ULg et al

in Process Biochemistry (2013), 48(11), 1914-1920

The purpose of the present study is to find the conditions allowing to reach the highest 24 h-yield(24 h- ) for the synthesis of mannosyl myristate catalyzed by the immobilized lipase B from Candida ... [more ▼]

The purpose of the present study is to find the conditions allowing to reach the highest 24 h-yield(24 h- ) for the synthesis of mannosyl myristate catalyzed by the immobilized lipase B from Candida antarctica (Novozym®435) in the ionic liquid (IL) [Bmpyrr][TFO] (1-butyl-1-methylpyrrolidinium tri-fluoromethanesulfonate). A full factorial design (FFD) was used in order to study the influence of three variables (temperature, mannose/vinyl myristate ratio and total substrate quantity) on the 24 h- . This design led to a model based on a second order polynomial response function. The resulting predicted con-tour plots have shown that the highest 24 h- should be obtained with high temperatures, low sugar/vinylester molar ratio and intermediate total substrate quantities (mmol). The model has been successfully verified and experimentally confirmed at the optimal conditions of 80◦C, substrate molar ratio of 1/10and total substrate quantity of 0.26 mmol leading to the highest predicted 24 h- of 72.2%. [less ▲]

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See detailCarbon nanotubes/polypropylene nanocomposites foams for EMI shielding applications
Tran, Minh Phuong ULg; Detrembleur, Christophe ULg; Thomassin, Jean-Michel ULg et al

Conference (2013, September 12)

In order to reduce the undesired effect of the electromagnetic interference, the developing of the materials with high capacity of electromagnetic interference (EMI) shielding has attracted a great ... [more ▼]

In order to reduce the undesired effect of the electromagnetic interference, the developing of the materials with high capacity of electromagnetic interference (EMI) shielding has attracted a great attention to scientific and industrial communities during last two decades.Indeed, polymer carbon nanotubes (CNTs) nanocomposites foams are addressed due to their high electrical conductivity and a great potential applications in electrostatic dissipation (ESD) and in electromagnetic interferences (EMI) shielding. However, the shortcoming of the addition of CNTs is that it usually leads to an increase of permittivity which results in enhancing undesirably the electromagnetic reflectivity due to the mismatch between the wave impedances for the signal propagating into air and into the absorbing material, respectively. To solve this problem, the introduction of air into these nanocomposites by the formation of foam will be favorable in order to reduce the permittivity of conductive composites. A good understanding of the influence of the foam structural parameters on the electrical properties of the foam will ultimately enable the optimum design of these materials for the targeted applications. A wide range of poly (propylene)/CNTs nanocomposites foams were synthesized using the supercritical CO2 technology. Different foaming parameters, such as the temperature, impregnation pressure will be controlled to modify the foam structure. Nanocomposite foams show higher electrical conductivity than non-foamed nanocomposites at the same volume content of CNTs. Effects of foam morphology such as cell density, pore size, volume expansion, and cell-wall thickness on electrical conductivity were comprehensively assessed. Similarly to our previous study on PMMA foam nanocomposites, the electrical conductivity of foams show higher value when the volume expansion is increased and when the average pore size is decreased. The preliminary EMI performances have highlighted that PP/CNTs foams containing 0.1 vol%CNTs are able to absorb about 90% of the incident radiation in the 25 to 40 GHz frequency range. [less ▲]

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See detailMorphology and electrical conductivity of poly(propylene)/multi-walled carbon nanotubes nanocomposites foams compatibilized by poly(propylene) -graft-maleic anhydride (PP-g-MA)
Tran, Minh Phuong ULg; Detrembleur, Christophe ULg; Alexandre, Michaël et al

Poster (2013, September 09)

The agglomerate of carbon nanotubes (CNTs) in poly(propylene) (PP) matrix often results in low electrical conductivity and poor mechanical properties. In order to improve the dispersion of CNTs, different ... [more ▼]

The agglomerate of carbon nanotubes (CNTs) in poly(propylene) (PP) matrix often results in low electrical conductivity and poor mechanical properties. In order to improve the dispersion of CNTs, different amounts of compatibilizer based on poly(propylene-graft-maleic anhydride) (PP-g-MA) were added in the PP matrix. Carbon nanotubes materbatches pre-dispersed at a high loading in the compatibilizer were used to create the samples used in this study. The nanocomposites of PP/PP-g-MA/CNTs were then foamed in supercritical carbon diozide (scCO2) followed by analysis of the foam morphology and the electrical conductivity. The presence of PPgMA did not significantly change the foam morphology, which exhibits good homogeneity and highly uniform closed-cells with penta-heptagonal cell-form. The expansion volume of the foams is not adversely affected by the addition of the compatibilizer; very high expansion volume (around 15 - 25 times) was achieved. The most interesting point is that the PP-PPgMA - 4wt%CNTs foams show a significantly higher electrical conductivity than the uncompatibilized PP-4wt%CNTs at the same volume percent content of CNTs [less ▲]

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See detail"Product-oriented engineering" applied to the development of porous scaffolds for tissue engineering.
de Bien, Charlotte ULg; Ounally, Thameur ULg; Collard, Valérie ULg et al

in Procedia Engineering (2013, September 02)

This work applies a “product-oriented engineering” approach to the development of porous scaffolds for tissue engineering. Polylactic acid scaffolds were obtained by a freeze-drying process. Their 2D/3D ... [more ▼]

This work applies a “product-oriented engineering” approach to the development of porous scaffolds for tissue engineering. Polylactic acid scaffolds were obtained by a freeze-drying process. Their 2D/3D microstructure was characterized by X-ray microtomography and related to the operating conditions used. Two types of scaffold end-use properties were characterized in relation to their microstructure: the mechanical and the transport properties. Scaffold young's modulus was computed from data measured on tension-compression devices. To evaluate the permeability, Darcy’s experiments were carried out. The obtained results allowed highlighting the quantitative relationships existing between elaboration conditions, microstructure and end use properties of the fabricated PLA scaffolds. [less ▲]

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See detailTunable self-assembled nanogels composed of well-defined thermoresponsive hyaluronic acid-polymer conjugates
Jing, Jing; Alaimo, David ULg; De Vlieghere, Elly et al

in Journal of Materials Chemistry B (2013), 1(32), 3883-3887

Here we report that grafting temperature-responsive polymers onto hyaluronic acid allows temperature-induced self-assembly into nanogels with tunable size. These nanogels can be easily loaded with ... [more ▼]

Here we report that grafting temperature-responsive polymers onto hyaluronic acid allows temperature-induced self-assembly into nanogels with tunable size. These nanogels can be easily loaded with hydrophobic molecules and hold potential for anti-cancer drug delivery towards human ovarian cancer cells. [less ▲]

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See detailTailor made amphiphilic copolymers for the design of smart drug delivery systems
Riva, Raphaël ULg; Cajot, Sébastien; Jérôme, Christine ULg

Conference (2013, August 21)

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See detailDevice-based controlled local delivery for the treatment of peritoneal pathologies
Riva, Raphaël ULg; Krier, Fabrice; Defrère, Sylvie et al

Poster (2013, August 18)

This contribution aims at reporting the developpment of a controlled drug delivery system (DDS) dedicated to the treatment of intra-peritoneal pathologies, especially endometriosis. At present time ... [more ▼]

This contribution aims at reporting the developpment of a controlled drug delivery system (DDS) dedicated to the treatment of intra-peritoneal pathologies, especially endometriosis. At present time, endometriosis is generally treated by daily oral absorption of drug with the purpose to improve the life quality of patients by the reduction of the pain caused by endometrial lesions. Nevertheless, deleterious side-effects, mainly infertility, are observed as a consequence of the important amount of absorbed active principle. One main advantage of controlled drug delivery devices, e.g. polymer implants, is to maintain sustained drug release over a prolonged period of time thereby eliminating fluctuations in the drug plasma concentration. Moreover, DDS allows a local release of the drug at a specific area, which significantly decreases the active principle concentration in the body and limits side-effects. The peritoneal cavity is a convenient site for the implantation of a DDS against endometriosis because large parts of lesion are localized in this region. At our knowledge, no application of an implant dedicated to the treatment of endometriosis is reported in the literature, whereas the local controlled release of an active principle presents several advantages compared to systemic administration. In this study, anastrozole (2,2’-[5-1H-1,2,4-triazole-1-yl-methyl)-1,3-phenylene]bis(2-methylpropiononitrile)), a well-known aromatase-inhibiting drug, was selected as active molecule. Typically, two non-biodegradable polymers were tested for the elaboration of an anastrozole loaded intra-peritoneal implant, namely polydimethylsiloxane (PDMS) and poly(ethylene-co-vinyl acetate) (EVA). As preliminary research, the ‘in vivo’ biocompatibility of PDMS and EVA in the intra-peritoneal cavity was confirmed by implantation of PDMS and EVA rod-shaped implants in rats. The kinetic of release was determined ‘in vitro’ and confirmed ‘in vivo’. Besides, the efficiency of the implants was improved by the addition of a polymer membrane, which allowed a controlled release of anastrozole over a period of 400 days. [less ▲]

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See detailMacroporous poly(ionic liquid)s and poly(acrylamide)s monoliths from CO2-in-water emulsion templates stabilized by sugar-based surfactants
Boyère, Cédric ULg; Favrelle, Audrey; Léonard, Alexandre ULg et al

in Journal of Materials Chemistry A (2013), 1(29), 8479-8487

Highly interconnected poly(acrylamide) (PAM) and poly(vinylimidazolium) (PVIm) porous monoliths were templated by carbon 10 dioxide-in-water (CO2/W) high internal phase emulsions (HIPEs), a toxic-solvent ... [more ▼]

Highly interconnected poly(acrylamide) (PAM) and poly(vinylimidazolium) (PVIm) porous monoliths were templated by carbon 10 dioxide-in-water (CO2/W) high internal phase emulsions (HIPEs), a toxic-solvent free process. A range of sugar-based fluorinated surfactants prepared by chemoenzymatic synthesis were used as emulsifiers. Both the concentration and the structure of the surfactants, especially the length of their CO2-philic part and of their spacer between the sugar head and the tail, were found to strongly affect the cellular structure and morphology of the PAM polyHIPEs, i.e. the size of pores and cells. A mannose derivative bearing a chain ranging from 6 to 10 perfluorinated carbons and a long spacer emerged as the best stabilizer, leading to a porous monolith with average pores and 15 cells sizes (about 2.6 1m and 5-10 1m, respectively) among the lowest reported for polyHIPEs produced from CO2/W emulsions. The same template then served for the preparation of the first macroporous poly(ionic liquid)s (PILs) polyHIPE by using 1-vinyl-3- ethylimidazolium bromide as monomer. Shrinkage of the final material was prevented by adjusting the divinylimidazolium crosslinker content. The resulting low density polyHIPE exhibits small spherical cells (~5 1m) connected by numerous small pores (~2 1m), confirming that the CO2/W HIPE templating methodology based on fluorinated glycosurfactants is a technique of choice for the 20 preparation of macroporous PILs. [less ▲]

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See detailElectrografting onto ITO substrates of poly(thiophene)-based micelles decorated by acrylate groups
Ouhib, Farid ULg; Desbief, Simon; Lazzaroni, Roberto et al

in Polymer Chemistry (2013), 4(15), 4151-4161

We report on a simple process for the chemisorption of poly(thiophene)-based block copolymers onto ITO substrates. Two poly(thiophene) block copolymers functionalized by acrylates on the second block are ... [more ▼]

We report on a simple process for the chemisorption of poly(thiophene)-based block copolymers onto ITO substrates. Two poly(thiophene) block copolymers functionalized by acrylates on the second block are prepared by the Grignard Metathesis (GRIM) process. The first block is composed of poly(3-hexylthiophene) (P3HT) and the second block is either a polythiophene bearing an acrylate group on each monomer unit (PAcET), or a polythiophene bearing both acrylate and poly(ethylene glycol) side chains (P(AcET-co-PEGET)). After characterizing their macromolecular parameters and optical properties, we investigate their ability to self-assemble into micelles in DMF solutions. This solvent is required for the electrografting procedure that is used for strongly anchoring the polymer to ITO. These micelles are expected to be formed by a P3HT core and a PAcET or P(AcET-co-PEGET) shell. When PEG side chains are present in the second block, the copolymer nicely self-assembles into micelles decorated by acrylates. Cathodic polarization of ITO induces chemisorption and polymerization of acrylate groups, leading to an adherent organized film of poly(thiophene)-based micelles. The optical absorption spectra show that the electrografted polymer chains have a degree of π-electron conjugation similar to that of crystalline P3HT films. In the absence of the PEG chains, the copolymer does not organize into micelles, due to the low stabilizing ability of the second block in DMF. [less ▲]

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See detailA novel strategy towards cyclic aliphatic (co)polyesters
Gao, Ch; Li, Y; Chi, J et al

in eXPRESS Polymer Letters (2013), 7(8), 690-702

This feature article focuses on a novel strategy towards macrocyclic (co)polyesters that combines controlled ring-opening polymerization of lactones initiated by a cyclic tin(IV) dialkoxide and ... [more ▼]

This feature article focuses on a novel strategy towards macrocyclic (co)polyesters that combines controlled ring-opening polymerization of lactones initiated by a cyclic tin(IV) dialkoxide and intramolecular cyclization by photocross- linking of pendant unsaturations next to the propagating sites. No linear species is ever involved in the polymerization and permanent cyclization steps, which allows higher molecular weight macrocycles to be prepared with high efficiency and no need for further purification. Moreover, this synthetic route is very flexible to the point where macrocyclic polyesters with more complex although well-defined architectures, such as tadpole-shaped and sun-shaped copolyesters, can be tailored. Synthesis of well-defined eight-shaped polyesters and twin tadpole-shaped copolymers has also been explored by using a spirocyclic tin(IV) alkoxides as an initiator. When functional lactones were introduced, the ‘click’ copper-mediated cycloaddition [3+2] reaction was utilized to make the eight-shaped and twin tadpole-shaped copolyesters amphiphilic. [less ▲]

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See detailCharacterization and optimization of GMO-based gels with long term release for intraarticular administration
Réeff, J.; Gaignaux, A.; Goole, J. et al

in International Journal of Pharmaceutics (2013), 451(1-2), 95-103

Osteoarthritis is characterized by slow degenerative processes in the articular cartilage within synovial joints. It could be interesting to develop a sustained-release formulation that could be effective ... [more ▼]

Osteoarthritis is characterized by slow degenerative processes in the articular cartilage within synovial joints. It could be interesting to develop a sustained-release formulation that could be effective on both pain/inflammation and restoration of mechanical integrity of the joint. Recently, an injectable system based on glycerol monooleate (GMO), containing clonidine as a model hydrophilic analgesic/anti-inflammatory drug and hyaluronic acid as a viscoelastic scaffold, showed promising potential as a biodegradable and biocompatible preparation to sustain the drug activity. However, drug release from the system is relatively fast (complete within 1 week) and the underlying drug release mechanisms not fully understood. The aims of this study were: (i) to significantly improve this type of local controlled drug delivery system by further sustaining clonidine release, and (ii) to elucidate the underlying mass transport mechanisms. The addition of FDA-approved inactive ingredients such as sodium oleate or purified soybean oil was found to be highly effective. The release rate could be substantially reduced (e.g., 50% release after 10 days), due to the increased hydrophobicity of the systems, resulting in slower and reduced water uptake and reduced drug mobility. Interestingly, Fick's second law of diffusion could be used to quantitatively describe drug release. [less ▲]

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See detailBiomimetic polymers
Clement, Benoît ULg; Vanslambrouck, Stéphanie ULg; Koole, Leo H. et al

Poster (2013, July 08)

Detailed reference viewed: 15 (2 ULg)