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See detailLes macrolichens de Belgique, du Luxembourg et du nord de la France. Clés de détermination
Sérusiaux, Emmanuël ULg; Diederich, Paul; Lambinon, Jacques ULg

Book published by Musée d'histoire naturelle Luxembourg (2004)

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See detailThe Macrolide Antibiotic Azithromycin Interacts With Lipids And Affects Membrane Organization And Fluidity: Studies On Langmuir-Blodgett Monolayers, Liposomes And J774 Macrophages
Tyteca, D.; Schanck, A.; Dufrene, Yf. et al

in Journal of Membrane Biology (2003), 192(3), 203-215

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See detailMacrolophus pygmaeus (Rambur) as an efficient predator of the tomato leafminer Tuta absoluta (Meyrick) in Europe. A review
De Backer, Lara ULg; Caparros Megido, Rudy ULg; Haubruge, Eric ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014)

The tomato leafminer, Tuta absoluta (Meyrick), originates from South America, and remains one of the main tomato pests in this continent. Since its introduction to Europe in 2006, Mediterranean countries ... [more ▼]

The tomato leafminer, Tuta absoluta (Meyrick), originates from South America, and remains one of the main tomato pests in this continent. Since its introduction to Europe in 2006, Mediterranean countries have also been exposed to this pest. Because of the endophytic habits of the larvae and ability of adults to reproduce parthenogenetically, chemicals and sexual pheromone- based control methods generate poor results. Recently, the use of biocontrol agents, such as Macrolophus pygmaeus Rambur (Heteroptera: Miridae), has been investigated as an alternative means of control, the results of which are presented in this review. Macrolophus pygmaeus is a mirid bug that is widely used to control different phytophagous insects in integrated pest management strategies through Europe. Several studies have confirmed the high predation potential of M. pygmaeus on T. absoluta under laboratory and semi-field conditions. This predator spontaneously colonizes tomato greenhouses in the southern Mediterranean countries. The use of banker plants (i.e., plants that provide a habitat to the predator) improves the colonization ability of this natural enemy. Hence, if the local population size is low, an augmentative strategy could be adopted. Predators may be released before or after the onset of pest infestation, with recommendations varying depending on natural population densities of both the pest and predator. The efficiency of M. pygmaeus has also been evaluated when used in combination with other biocontrol agents or with chemicals. This work presents an overview of different types of control strategies using M. pygmaeus against the tomato leafminer, T. absoluta. [less ▲]

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See detailMacromixing versus hydrodynamics in trickle-flow columns
Crine, Michel ULg; Marchot, Pierre ULg; Lekhlif, B. et al

in Chemical Engineering Science (1992), 47

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See detailMacromolecular engineering of aliphatic polyesters
Lecomte, Philippe ULg

Scientific conference (2003, September)

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See detailMacromolecular engineering of aliphatic polyesters based on macrocyclic units
Lecomte, Philippe ULg; Li, Haiying; Riva, Raphaël ULg et al

Poster (2007, August 31)

The last decades have witnessed a steadily increasing progress in the macromolecular engineering of the main families of synthetic polymers. Ring-shaped copolymers show a unique topology due to the ... [more ▼]

The last decades have witnessed a steadily increasing progress in the macromolecular engineering of the main families of synthetic polymers. Ring-shaped copolymers show a unique topology due to the absence of any chain-end and exhibit distinct properties from their linear counterparts, such as glass transition temperature, order-disorder transition, reduced viscosity, lower hydrodynamic volumes. This communication aims at reporting on a novel route to biodegradable cyclic polyesters. Our strategy is based on the work of Prof. Kricheldorf who initiated the ring-opening polymerization of ε-caprolactone by cyclic tin dialkoxides, e.g., 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP) in order to obtain “living” macrocyclic PCL, still containing two endocyclic tin-oxygen bonds. In this work, the resumption of polymerization by a few units of ε-caprolactone substituted by an acrylic unit, e.g., 1-(2-oxooxepan-3-yl)ethyl prop-2-enoate, followed by intramolecular photo-cross-linking of pendant unsaturations and finally by hydrolysis gave rise to macrocyclic PCL. As a rule, this strategy is very well-suited for the synthesis of high molecular weight PCL. Moreover, tin alkoxides were kept untouched after the cross-linking step and remained thus available for further macromolecular engineering. The process was extended to the synthesis of other architectures such as sun-shaped, two-tail tadpole-shaped, eight-shaped and symmetrical four-tail eight-shaped copolyesters. [less ▲]

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See detailMacromolecular engineering of aliphatic polyesters by click chemistry
Lecomte, Philippe ULg

Scientific conference (2009, September 10)

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See detailMacromolecular engineering of aliphatic polyesters by ring-opening polymerization
Lecomte, Philippe ULg; Jérôme, Christine ULg; Jérôme, Robert ULg

Conference (2008, September 09)

During the past few years, a steadily increasing attention was paid to the synthesis of biodegradable and biocompatible aliphatic polyesters because of potential applications as biomaterials or as ... [more ▼]

During the past few years, a steadily increasing attention was paid to the synthesis of biodegradable and biocompatible aliphatic polyesters because of potential applications as biomaterials or as environmentally friendly thermoplastics. The first purpose of this work is to show that the modification of these aliphatic polyesters by pendant functional groups is an efficient tool to tailor the main properties, including biodegradation rate, bioadhesion, hydrophilicity, degree of crystallinity. The strategies implemented for the synthesis of aliphatic polyesters bearing pendant functional groups rely on the synthesis of g-substituted e-caprolactones followed by their ring-opening polymerization and on the chemical modification of duly functionalized aliphatic polyesters.The second part of the lecture will be dedicated to some recent examples dealing with the use of functional caprolactones to prepare various architectures such as star-shaped copolymers, graft copolymers, macrocycles and networks. [less ▲]

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See detailMacromolecular engineering of biodegradable polyesters by ring-opening polymerization and 'Click' chemistry
Lecomte, Philippe ULg; Riva, Raphaël ULg; Jérôme, Christine ULg et al

in Macromolecular Rapid Communications (2008), 29(12-13), 982-997

Biodegradability makes aliphatic polyesters valuable candidates for biomaterials and environmentally friendly thermoplastics. Nevertheless, their chemical modification, which is mandatory for a series of ... [more ▼]

Biodegradability makes aliphatic polyesters valuable candidates for biomaterials and environmentally friendly thermoplastics. Nevertheless, their chemical modification, which is mandatory for a series of potential applications, is usually a problem because it must be carried out under very mild conditions in order to prevent degradation by hydrolysis and/or transesterification from occurring. In this review, the copper(i) -catalyzed azide-alkyne cycloaddition, which is a click reaction, is shown to be very efficient to bypass these problems and to tailor the macromolecular architecture and functionality of those polyesters without facing undesired degradation reactions. [less ▲]

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See detailMacromolecular engineering of cyclic aliphatic polyesters
Li, Haiying

Doctoral thesis (2007)

This works aims at reporting a novel strategy that combines the controlled ring-opening polymerization of lactones initiated by a cyclic tin(IV) dialkoxide and intramolecular cyclization by photo-cross ... [more ▼]

This works aims at reporting a novel strategy that combines the controlled ring-opening polymerization of lactones initiated by a cyclic tin(IV) dialkoxide and intramolecular cyclization by photo-cross-linking of pendant unsaturations next to the propagating sites. No linear species is ever involved in the polymerization, which allows higher molecular weight macrocycles to be prepared with high efficiency. Moreover, the 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 star- and eight-shaped polyesters and twin tadpole-shaped amphiphilic copolymers has also been explored by using a spirocyclic tin(IV) alkoxide as an initiator. [less ▲]

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See detailMacromolecular engineering of cyclic aliphatic polyesters by ring-opening polymerization
Lecomte, Philippe ULg; Riva, Raphaël ULg; Li, Haiying et al

Conference (2006, September 24)

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See detailMacromolecular engineering of cyclic aliphatic polyesters by ring-opening polymerization and "click" chemistry
Lecomte, Philippe ULg; Li, Haiying; Riva, Raphaël ULg et al

Conference (2007, September 04)

The last decades have witnessed a steadily increasing progress in the macromolecular engineering of the main families of synthetic polymers. Ring-shaped copolymers show a unique topology due to the ... [more ▼]

The last decades have witnessed a steadily increasing progress in the macromolecular engineering of the main families of synthetic polymers. Ring-shaped copolymers show a unique topology due to the absence of any chain-end and exhibit distinct properties from their linear counterparts, such as glass transition temperature, order-disorder transition, reduced viscosity, lower hydrodynamic volumes. This communication aims at reporting on a novel route to biodegradable cyclic polyesters. Our strategy is based on the work of Prof. Kricheldorf who initiated the ring-opening polymerization of ε-caprolactone by cyclic tin dialkoxides, e.g., 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP) in order to obtain “living” macrocyclic PCL, still containing two endocyclic tin-oxygen bonds. In this work, the resumption of polymerization by a few units of ε-caprolactone substituted by an acrylic unit, e.g., 1-(2-oxooxepan-3-yl)ethyl prop- 2-enoate, followed by intramolecular photo-crosslinking of pendant unsaturations and finally by hydrolysis gave rise to macrocyclic PCL. As a rule, this strategy is very well-suited for the synthesis of high molecular weight PCL. Moreover, tin alkoxides were kept untouched after the cross-linking step and remained thus available for further macromolecular engineering. The process was extended to the synthesis of other architectures such as sun-shaped, two-tail tadpoleshaped, and eight-shaped copolyesters. The second part of the lecture, it will be shown that the copper(I)-catalyzed Huisgen’s [3+2] cycloaddition, which is the most popular “Click" reaction, is very efficient to graft alkynes, duly substituted by functional groups or chains, onto aliphatic copolyesters bearing pendant azides. Interestingly enough, mild conditions were found and no degradation was observed during the “click” derivatization of copolyesters of PCL. The “click” reactions of alkynes onto pendant azides of copolyesters of PLA, by far more sensitive than PCL, was also successfully carried out without any detectable degradation. ”Click” chemistry is very versatile because this reaction was successfully implemented to graft functional groups or chains directly onto ω-azido-ε-caprolactone, without any ring-opening of the lactone, in order to make available a new range of functional caprolactones. Finally, the “click” grafting of PEO onto the tails of tadpole-shaped copolymers will be shown to be a route to amphiphilic copolymers with an original architecture. [less ▲]

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See detailMacromolecular engineering of lactone-based (co)polymers for biomedical applications
Dubois, Philippe ULg; Grandfils, Christian ULg; Jérôme, Robert ULg et al

in Polymer Chemistry (1991), 32 (1)

Ring-opening polymerization of epsilon-caprolactone and lactides by aluminum alkoxides allows aliphatic polyesters to be tailored at will and fitted to requirements for biomedical applications ... [more ▼]

Ring-opening polymerization of epsilon-caprolactone and lactides by aluminum alkoxides allows aliphatic polyesters to be tailored at will and fitted to requirements for biomedical applications, particularly for controlled drug delivery systems. Variation in molecular weight controls the effective life time of microspheres or implants in vivo. Block copolymerization leads to microphase separated materials and opportunity to modify the overall release kinetics and to get, for instance, a zero-order. Macromonomers and dimacromonomers are ideal precursors for physically and chemically stabilized hydrogels, respectively. Dimacromonomers can actually generate amphiphilic networks. [less ▲]

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See detailMacromolecular engineering of lactones and lactides. 24. Controlled synthesis of (R,S)-β-butyrolactone-b-ε-caprolactone block copolymers by anionic and coordination polymerization
Kurcok, Piotr; Dubois, Philippe ULg; Sikorska, Wanda et al

in Macromolecules (1997), 30(19), 5591-5595

Block copolymers of (R,S)-β-butyrolactone and ε-caprolactone have been synthesized by combining the anionic polymerization of the first monomer with the coordinative ring-opening polymerization of the ... [more ▼]

Block copolymers of (R,S)-β-butyrolactone and ε-caprolactone have been synthesized by combining the anionic polymerization of the first monomer with the coordinative ring-opening polymerization of the second one. The copolymerization yield is close to 100% and the final molecular weight of each sequence can be predicted from the initial monomer-to-initiator molar ratio. The molecular weight distribution of copolymers obtained is quite narrow (Mw/Mn ≤ 1.3). According to NMR and DSC analysis, the polybutyrolactone block is atactic and totally amorphous, in contrast to the polycaprolactone block which is semicrystalline. A partial miscibility of the two blocks in the amorphous phase has however been detected. Thermal and enzymatic degradations of the block copolymers have been investigated. The enzymatic degradation rate promoted by the lipase form Rhizopus arrhizus strongly depends on the copolyester composition and increases with the β-butyrolactone content. [less ▲]

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See detailMacromolecular engineering of poly(ε-caprolactone) based on macrocyclic units
Lecomte, Philippe ULg; Li, Haiying; Riva, Raphaël ULg et al

Poster (2007, May 24)

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See detailMacromolecular engineering of polylactones and polylactides. 11. Synthesis and use of alkylaluminium dialkoxides and dithiolates as promoters of hydroxy telechelic poly(epsilon-capprolactone) and alph,omega-dihydroxy triblock copolymers containing outer polyester blocks
Dubois, Philippe; Degée, Philippe; Jérôme, Robert ULg et al

in Macromolecules (1993), 26(11), 2730-2735

Diethylaluminum dialkoxides (Et2AlOXOAlEt2, where X is either an aliphatic radical or a polymer chain) and related dithiolates have been investigated as potential initiators for the ring-opening ... [more ▼]

Diethylaluminum dialkoxides (Et2AlOXOAlEt2, where X is either an aliphatic radical or a polymer chain) and related dithiolates have been investigated as potential initiators for the ring-opening polymerization of ε-caprolactone. Hydroxy telechelic poly(ε-caprolactone) and alpha,omega-dihydroxypoly(ε-caprolactone-b-X-b-ε-caprolactone) have been accordingly prepared and characterized. A hydroxy group is selectively attached at both ends as demonstrated by IR and H-1 NMR spectroscopies and confirmed by titration of the derivatized alpha,omega-dicarboxylic acid (co)polymers. Polymerization of epsilon-caprolactone is living and yields linear polyester chains of a predictable molecular weight and of quite a narrow molecular weight distribution. [less ▲]

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See detailMacromolecular engineering of polylactones and polylactides. 12. Study of the depolymerizatin reactions of poly(ε-caprolactone with functional aluminum alkoxide end groups
Dubois, Philippe; Barakat, Ibrahim; Jérôme, Robert ULg et al

in Macromolecules (1993), 26(17), 4407-4412

Ring-opening polymerization of epsilon-caprolactone has been initiated with functional aluminum alkoxides in toluene at 25-degrees-C. Degradation of ''living'' polyester chains by transesterification ... [more ▼]

Ring-opening polymerization of epsilon-caprolactone has been initiated with functional aluminum alkoxides in toluene at 25-degrees-C. Degradation of ''living'' polyester chains by transesterification reactions has been studied in relation to temperature, solvent polarity, average molecular weight, and structure of the initiator, i.e., the nature of the functional group and the number of alkoxides per Al atom. Degradation products, particularly cyclic oligomers, have been isolated by supercritical fluid extraction (SFE) and characterized by GC-MS. The effect of Lewis bases on transesterification reactions has been investigated and discussed in reference to the ''coordination-insertion'' mechanism. [less ▲]

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