Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailPolycaprolactone-based block copolymers. I - Synthesis by anionic-coordination type catalysts
Heuschen, J.; Jérôme, Robert ULg; Teyssié, Philippe

in Macromolecules (1981), 14(2), 242-246

Bimetallic µ-oxalok oxides are very active anionic coordination type catalysts in the living polymerization of t-caprolactone. These compounds have a well-defined composition which can be systematically ... [more ▼]

Bimetallic µ-oxalok oxides are very active anionic coordination type catalysts in the living polymerization of t-caprolactone. These compounds have a well-defined composition which can be systematically modified. It is proposed that at least half the alkoxy groups of these catalysts are replaced by carboxylate ones and the remaining alkoxy groups by any hydroxyl-terminated polymer PX. These new polymer PX-supported catalysts are powerful tools in tailoring poly(ε-capro1actone) block copolymers with well controlled molecular parameters. [less ▲]

Detailed reference viewed: 26 (1 ULg)
Full Text
See detailPolycationes: interacciones con estructuras biológicas y futuras aplicationes
Grandfils, Christian ULg; Foresto, Patricia; Valverde, N et al

Conference (2004, December 02)

Detailed reference viewed: 5 (0 ULg)
See detailPolycations : relationship between chemical structure and biological behavior
Grandfils, Christian ULg; Peulen, Olivier ULg; Deloyer, Patricia et al

in Morgan, D.; White, A.; Sanchez-Jimenez, F. (Eds.) et al COST 917 Biologically active amines in food. Volume IV (2000)

Detailed reference viewed: 18 (6 ULg)
Full Text
See detailPolycations and biological behaviour
Grandfils, Christian ULg

Scientific conference (2005, October 19)

Detailed reference viewed: 13 (0 ULg)
Full Text
See detailPolycations: relationship between chemical structure and biological behaviour
Grandfils, Christian ULg; Peulen, Olivier ULg; Deloyer, P et al

in Biologically active amines in food (2000)

Detailed reference viewed: 7 (4 ULg)
Peer Reviewed
See detailPolychlorinated Biphenyls affect Histological Appearance of European sea bass (Dicentrarchus labrax) Thyroids
Schnitzler, Joseph ULg; Klaren, Peter; Celis, Niko et al

Conference (2010)

Polychlorobiphenyls (PCBs) are well-described endocrine disrupters and of particular interest are effects on thyroid function. We propose here a thorough approach to assess effects of these compounds on ... [more ▼]

Polychlorobiphenyls (PCBs) are well-described endocrine disrupters and of particular interest are effects on thyroid function. We propose here a thorough approach to assess effects of these compounds on the thyroid function of European sea bass (Dicentrarchus labrax). An experimental exposure of sea bass to commercial PCB mixtures has been designed to understand underlying toxicity mechanisms and effects on the thyroid system. After 120 days of exposure histological appearance of thyroid tissue was assessed by light and electron microscopy. The follicle area, perimeter, diameter, length and with of every follicle cross section were interactively measured. The shape of the follicles was described with three dimensionless shape descriptors: roundness, form factor and aspect ratio. The histomorphometrical analysis showed a greater heterogeneity of thyroid follicle diameter and especially higher epithelial cell heights in sea bass exposed to environmental relevant doses of PCB (from 0.3 to 0.9 μg g-1 [7 ICES PCB]). Ultrastructural histological investigations showed that the epithelial cells surrounding the bigger follicles present an higher accumulation of colloid droplets. This was interpreted to be the result of increased stimulation of follicular cells. No differences in shape could be identified among the different treatment groups The size of the follicles and the form of the follicular cells gives an indication of the secretary activity of the gland. These observations support the hypothesis that the contamination of PCB mixtures can induce a hyperactivity of the thyroid tissue. These observations were confirmed by measurements of muscular thyroid hormone concentrations and activity thyroid hormone metabolism. [less ▲]

Detailed reference viewed: 76 (1 ULg)
Full Text
Peer Reviewed
See detailpolychlorinated biphenyls contamination in women with breast cancer
Charlier, Corinne ULg; Albert, Adelin ULg; Zhang, Lixin ULg et al

in Clinica Chimica Acta (2004), 347

Detailed reference viewed: 41 (14 ULg)
Peer Reviewed
See detailPolyclonal Bovine Sera But Not Virus-Neutralizing Monoclonal Antibodies Block Bovine Leukemia Virus (Blv) Gp51 Binding To Recombinant Blv Receptor Blvrcp1
Orlik, O.; Ban, J.; Hlavaty, J. et al

in Journal of Virology (1997), 71(4),

Detailed reference viewed: 9 (2 ULg)
See detailLa polyendocrinopathie de type 1, de la clinique au gêne
Beckers, Albert ULg

Scientific conference (2001, November 23)

Detailed reference viewed: 1 (0 ULg)
See detailLes polyendocrinopathies de type I, aspect épidémiologique
Beckers, Albert ULg

Scientific conference (1993, May 14)

Detailed reference viewed: 6 (0 ULg)
See detailLes polyendocrinopathies de type I
Beckers, Albert ULg

Scientific conference (1994, April 08)

Detailed reference viewed: 1 (0 ULg)
See detailLes polyendocrinopathies de type I
Beckers, Albert ULg

Scientific conference (1995, February 23)

Detailed reference viewed: 1 (0 ULg)
Full Text
Peer Reviewed
See detailPolyester layered silicate nanohybrids by controlled grafting polymerization
Lepoittevin, Bénédicte; Pantoustier, Nadège; Alexandre, Michaël ULg et al

in Journal of Materials Chemistry (2002), 12(12), 3528-3535

Poly( epsilon-caprolactone) (PCL) layered silicate nanohybrids were synthesized by ring opening polymerization of epsilon-caprolactone according to a well-controlled coordination-insertion mechanism ... [more ▼]

Poly( epsilon-caprolactone) (PCL) layered silicate nanohybrids were synthesized by ring opening polymerization of epsilon-caprolactone according to a well-controlled coordination-insertion mechanism. Montmorillonites were surface-modified by non functional (trimethylhexadecylammonium) and hydroxy functional alkylammonium cations, i.e., (2-hydroxyethyl) dimethylhexadecylammonium. The hydroxy functions available at the clay surface were activated into tin( II or IV) or Al(III) alkoxide initiators for lactone polymerization, thus yielding surface-grafted PCL chains. The surface-grafted PCL chains were recovered by an ionic exchange reaction with lithium chloride and they were analyzed by size exclusion chromatography. The PCL molar mass was measured as a function of the hydroxy content of the clay that was modulated by exchanging the Na cations with mixtures of non-functional and hydroxy functional ammonium cations of different compositions. Nanohybrids were also characterized by small-angle X-ray diffraction, transmission electron microscopy and thermogravimetry. The PCL molar mass and the nanocomposite morphology (i.e., exfoliation and/or intercalation) were readily tuned by the content of the hydroxy groups available at the clay surface. Surface-grafted aluminium trialkoxide species proved highly efficient in initiating polymerization that leads to PCL chains of controlled molar mass and narrow molecular weight distribution with polydispersity indices as low as 1.2. [less ▲]

Detailed reference viewed: 17 (0 ULg)
Full Text
Peer Reviewed
See detailPolyester nanoparticles presenting mannose residues : toward the development of new vaccine delivery systems combining biodegradability and targeting properties
Rieger, Jutta ULg; Freichels, Hélène ULg; Imberty, Anne et al

in Biomacromolecules (2009), 10(3), 651-657

We report the synthesis of fully biodegradable polymeric nanoparticles presenting mannose residues at their surface and their interaction with lectins. A simple and versatile method was used to reach the ... [more ▼]

We report the synthesis of fully biodegradable polymeric nanoparticles presenting mannose residues at their surface and their interaction with lectins. A simple and versatile method was used to reach the surface functionalization of poly(d,l-lactic acid) (PLA) nanoparticles by mannose moieties: It consists in using an amphiphilic mannosylated poly(ethylene oxide)-b-poly(-caprolactone) (PEO-b-PCL) diblock copolymer as a bioresorbable surface modifier in a simple nanoprecipitation-evaporation procedure. The size and zeta potential of the nanoparticles were found to depend on the molar copolymer/PLA ratio, demonstrating the influence of the copolymer on the formation of the nanoparticles. The bioavailability of the mannose residues as specific recognition sites on the nanoparticle surface could be demonstrated by a modified enzyme-linked lectin assay (ELLA) using biotin-labeled lectins which interact specifically with α-d-mannopyrannoside derivatives. Besides specific interaction by lectin−mannose complex formation, nonspecific adsorption of the proteins on the nanoparticle surface was observed. These results were fully supported by isothermal titration calorimetry experiments which suggested that the balance between specific and nonspecific interactions can be controlled by the amount of glycosylated polymer used for the preparation of the nanoparticles. Such nanoparticles are expected to be specifically recognized by mannose receptors, which are highly expressed in cells of the immune system. The targeting properties of these carrier systems combined with their potential adjuvant effects due to their size in the range of 200−300 nm make them attractive candidates as vaccine delivery systems. [less ▲]

Detailed reference viewed: 58 (7 ULg)
Full Text
Peer Reviewed
See detailPolyester-based microcarriers with enhanced surface properties for tissue engineering
Markvicheva, Elena; Privalova, Anna; Sevrin, Chantal ULg et al

Poster (2014, June 17)

Detailed reference viewed: 3 (0 ULg)
Full Text
See detailPolyéthylène - Mise au point de techniques analytiques sur Catalyseurs et Prépolymères au Chrome
Olive, Gilles ULg

Master's dissertation (1993)

Situation du sujet Les sujets de mon stage étaient: - Mise au point d'une méthode de dosage de l'aluminium dans les catalyseurs au chrome - Mise au point d'une technique analytique (FX) sur les ... [more ▼]

Situation du sujet Les sujets de mon stage étaient: - Mise au point d'une méthode de dosage de l'aluminium dans les catalyseurs au chrome - Mise au point d'une technique analytique (FX) sur les prépolymères Parmi les différentes qualités de polyéthylène, notamment celle destinée à l'extrusion-souflage, on peut utiliser un catalyseur à base de chrome. Pour des raisons de cinétique et de sélectivité on modifie ces catalyseurs soit par du titane, soit par de l'aluminium. Or pour éviter tout problème, notamment les points chauds dans le réacteur, et pour obtenir la qualité désirée, il est nécessaire de bien connaître la composition du catalyseur. Le dosage du chrome et du titane ne pose pas de problème, alors que le dosage de l'aluminium fournit des résultats très inférieurs à la réalité. Par ailleurs, dans le procédé phase gaz BP, la prépolymérisation du catalyseur permet un meilleur contrôle de la morphologie, donc de la fiabilité. Lors de polymérisation, on doit connaître exactement la quantité de catalyseur injecté. pour cela, il faut savoir de façon précise le taux d'avancement du prépolymère. Il est donc nécessaire de faire une série d'étalons pour la FX, car la méthode actuelle (taux de cendres qui nécessite 1 heure pour donner le résultat) n'est pas applicable pour le suivi d'un atelier. Les résultats obtenus Analyse de l'aluminium dans les catalyseurs Après avoir comparé les différentes méthodes actuelles, et effectué quelques essais pour déterminer la meilleure méthode, une longue série de points (11 au total) fut réalisée afin d'évaluer la fiabilité d'une nouvelle méthode. Il ressort de cette étude que: - l'ajout d'acide chlorhydrique permet de mieux solubiliser l'aluminium - il n'est pas nécessaire de mettre 20% d'acide fluorhydrique, 10% suffisent pour solubiliser la silice et le chrome - en absorption atomique, il faut bien homogénéiser l'échantillon et avoir des étalons récents. Une fois cette étude terminée et les différentes vérifications effectuées sur des souches catalytiques bien connues, l'étude d'homogénéité de lot a pu commencer. Malgré le faible nombre de points, on remarque que dans un même fût le pourcentage d'aluminium ne varie que de 0.01% Synthèse de prépolymères étalons La synthèse des deux séries d'étalons destinés à la FX a permis de dégager les remarques suivantes: - il faut faire attention à la vanne de fond de réacteur. Celle-ci crée un volume mort dans lequel le catalyseur peut tomber et ne réagit plus - les prépolymères doivent toujours être manipulés et conservés à l'abri de l'air, sinon ils se dégradent et ne peuvent plus servir pour recaler la dérive normale de la FX - il faut bien vérifier l'homogénéité des prépolymères et des pastilles sinon on a des erreurs de l'ordre de 40% sur la mesure. [less ▲]

Detailed reference viewed: 34 (2 ULg)