References of "1996"
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See detailCompétences sociales dans l'Enseignement Secondaire Spécial de Forme 3
Duchâteau, Dominique ULg; Gimenez, Rosalia; Peeters, Robert ULg

Report (1996)

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See detailSAXS analysis of the morphology of biocompatible and biodegradable poly(ε-caprolactone-b-glycolide) copolymers1
Sobry, R.; Van den Bossche, Guy ULg; Fontaine, F. et al

in Journal of Molecular Structure (1996), 383(1-3), 63-68

Poly(epsilon-caprolacrone-b-glycolide) diblock copolyesters have been synthesized by the sequential polymerization of epsilon-caprolactone and glycolide as initiated by aluminium alkoxides ... [more ▼]

Poly(epsilon-caprolacrone-b-glycolide) diblock copolyesters have been synthesized by the sequential polymerization of epsilon-caprolactone and glycolide as initiated by aluminium alkoxides. Copolymerization is typically ''living'' and yields copolyesters of perfectly controlled molecular weight and composition. Diblock molecular weight (Mn-PGA+Mn-PCL) ranges from 5700 to 42000 and the rho = Mn-PCL/Mn-PGA ratio varies from 1.5 to 13.1. Due to the inherent insolubility of the polyglycolide (PGA) segment in common organic solvent, the diblock copolyesters form stable non-aqueous colloidal dispersions e.g. in toluene, the stability of which results from the soluble poly(epsilon-caprolactone) (PCL) block. Combining all the experimental observations (PCS, TEM, WAXS, SAXS, AFM), a micelle model has been proposed which consists of a polyglycolide core surrounded with a corona of polycaprolactone (PCL). Both constituents are semi crystalline. From SAXS observations, the PGA core is better described by two concentric spheres. The internal sphere of a 5-6.7 nn diameter would essentially contain crystalline PGA. The diameter of the external sphere, D-PGA, is in the range from 6.2 to 9.6 nm, at least for the investigated diblock copolymers. As a rule, this diameter increases as rho decreases at constant molecular weight and as the diblock molecular weight increases at constant rho. A scattering peak (weak) is observed in the range from 10.8 to 15.5 nm and the Bragg distance is close mu D-PGA, where mu is equal to (1+3 rho/2)(1/3). From steric considerations, mu is the ratio between the diameter of the micelle and the diameter of the PGA core, so that this peak has been assigned to the characteristic intermicellar distance. At very small angles, several additional peaks are the signature of a hyperstructure which is possibly lamellar. [less ▲]

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See detailStructural and Functional Aspects of Chloride Binding to Alteromonas Haloplanctis Alpha-Amylase
Feller, Georges ULg; le Bussy, O.; Houssier, C. et al

in Journal of Biological Chemistry (1996), 271(39), 23836-41

Chloride is the allosteric effector of vertebrate pancreatic and salivary alpha-amylases and of the bacterial alpha-amylase from Alteromonas haloplanctis. Activation experiments of A. haloplanctis alpha ... [more ▼]

Chloride is the allosteric effector of vertebrate pancreatic and salivary alpha-amylases and of the bacterial alpha-amylase from Alteromonas haloplanctis. Activation experiments of A. haloplanctis alpha-amylase by several monovalent anions show that a negative charge, not restricted to that of Cl-, is essential for the amylolytic reaction. Engineering of the chloride binding site reveals that a basic residue is an essential component of the site. The mutation K337R alters the Cl--binding properties, whereas the mutation K337Q produces an active, chloride-independent enzyme. Comparison of the Kd values for Cl- in three homologous alpha-amylases also indicates that the binding affinity is dependent on the chloride coordination mode by this basic residue. Analysis of substrate and chloride binding according to the allosteric kinetic model shows that the chloride effector is not involved in substrate binding. By contrast, the pH dependence of activity and experiments of chemical modifications and Ca2+ inhibition show that the chloride ion is responsible for the pKa shift of catalytic groups and interacts with active site carboxyl groups. [less ▲]

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See detailOptimalization of green note aldehydes production by a hydroperoxide lyase
Fauconnier, Marie-Laure ULg; Chot, C. E.; Marlier, M.

Poster (1996, September 26)

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See detailLarge scale production of 13-hydroperoxilinolenic acid using soybean lipoxygenase
Fauconnier, Marie-Laure ULg; Dessart, V.; Marlier, M.

Conference (1996, September 26)

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See detail'Self-Assembly of Alkanethiols on Gold: Molecular Structure and Surface Order Evidenced by XPS, UPS and HREELS'
Duwez, Anne-Sophie ULg; Yu, L.M.; Pireaux, J. et al

Conference (1996, September 23)

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See detailEuropean Citizenship
Martiniello, Marco ULg

Scientific conference (1996, September 23)

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See detailIntraarterial spiral CT angiography combined with DSA in pretherapeutic assessment of cerebral aneurysms.
Flandroy, P.; Vanderschelden, P.; Dondelinger, Robert ULg et al

Conference (1996, September 21)

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See detailModèle Hydrologique Basé sur la Physique du Ruissellement Applicable à des Terrains Naturels Digitalisés
Pirotton, Michel ULg

in 24èmes journées de l'Hydraulique (1996, September 18)

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See detailObservations on the Helminths of Harbour Porpoises (Phocoena Phocoena) and Common Guillemots (Uria Aalge) from the Belgian and German Coasts
Brosens, L.; Jauniaux, Thierry ULg; Siebert, U. et al

in Veterinary Record : Journal of the British Veterinary Association (1996), 139(11), 254-7

Between February 1990 and July 1991, 18 harbour porpoises (Phocoena phocoena) and 248 common guillemots (Uria aalge), found dead along the Belgian and German coasts, were examined for their burden of ... [more ▼]

Between February 1990 and July 1991, 18 harbour porpoises (Phocoena phocoena) and 248 common guillemots (Uria aalge), found dead along the Belgian and German coasts, were examined for their burden of helminths. A total of three species were found in the guillemots (one cestode, one nematode and one pentastomid), and six species in the porpoises (one trematode, one cestode and four nematodes). Among the guillemots the burden of helminths was not statistically different between juvenile and adult birds. The deaths of the birds were apparently not related to the parasite infections. In contrast, the adult porpoises were more heavily parasitised than the juveniles, except for one young porpoise stranded on the Belgian coast. In the porpoises, four species of parasites had a pathological effect and Torynurus convolutus was responsible for the death of one animal from the Belgian coast and three from the German coast. [less ▲]

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See detailInterests of pregnancy follow-up in cows after embryo transfer : special focusing on IVP & NT
Ectors, Fabien ULg; Drion, Pierre ULg; Delval, A. et al

(1996, September 13)

In this report, pregnancies were obtained after extreme in vitro conditions- IVM/F/C of the donor embryos, - IVM, enucleation and artificial activation of the recipient oocytes, - nuclear transfer and ... [more ▼]

In this report, pregnancies were obtained after extreme in vitro conditions- IVM/F/C of the donor embryos, - IVM, enucleation and artificial activation of the recipient oocytes, - nuclear transfer and - IVC of the reconstituted embryos. Even if the incidence of this syndrome is relatively low after embryo transfer, a possible increasing of its occurence cannot be excluded in correlation with an incomplete maturation of oocytes at the time of fertilization, smaller follicles giving non competent or partially competent oocytes. An other explanation of this syndrome resulting in the higher variation in newborn calves weight may be also partly explained by the in vitro conditions. The gametes and/or embryos may be submitted to media containing embryotoxic substances. In the other hand, gametes and/or embryos may not found embryotrophic substances in the media like growth factors... Owing to this phenomenon, strict recommendations should be followed concerning rigorous follow-up of pregnancies obtained after transfer of IVM/IVF/IVC or cloned embryos by pregnancy proteins (PSPB, PAG...) or hormone (placental lactogen, estrone sulfate) assay and, after birth, macroscopic examinations of newborn, cord and caroncules. [less ▲]

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See detailStudy on european forest information and communication system. Country report for Belgium
Lecomte, Hugues; Hebert, Jacques ULg; Rondeux, Jacques ULg

in study on european forest information and communication system (1996, September 12)

Belgium is divided into 3 regions : Walloon, Flemish and Brussels regions. Each one has its own political autonomy in various fields, in particular the natural resources management. Wooded area in the ... [more ▼]

Belgium is divided into 3 regions : Walloon, Flemish and Brussels regions. Each one has its own political autonomy in various fields, in particular the natural resources management. Wooded area in the walloon region covers 530,600 ha. A first temporary inventory has been realised in the beginning of the 1980s. A new permanent forest inventory is carried out since the beginning of the 1994. The Flemish region will start the first permanent inventory of its 128,600 ha of wooded area in 1997. With only 2,000 ha the Brussels region does not organise a forest inventory up to now. The method used in the Walloon region is summarised below as the Flemish inventory method is quite similar. [less ▲]

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See detailSyndiotactic poly(methyl methacrylate) (sPMMA)-polybutadiene (PBD)-sPMMA triblock copolymers: synthesis, morphology, and mechanical properties
Yu, Jian Ming; Dubois, Philippe ULg; Jérôme, Robert ULg et al

in Macromolecules (1996), 29(19), 6090-6099

A series of syndiotactic poly(methyl methacrylate) (sPMMA)−polybutadiene (PBD)−sPMMA triblock copolymers, or MBM, have been successfully synthesized by using dilithium initiators (DLi's) based on the ... [more ▼]

A series of syndiotactic poly(methyl methacrylate) (sPMMA)−polybutadiene (PBD)−sPMMA triblock copolymers, or MBM, have been successfully synthesized by using dilithium initiators (DLi's) based on the diadduct of tert-butyllithium (t-BuLi) to either 1,3-bis(1-phenylethenyl)benzene (PEB) or m-diisopropenylbenzene (m-DIB). The efficiency of these DLi's in building up MBM triblock copolymers has been compared under the same experimental conditions, i.e., in a cyclohexane/diethyl ether mixture for the butadiene polymerization at room temperature and in a cyclohexane/THF mixture for the MMA polymerization at −78 °C. Although all the synthesized copolymers show a monomodal, symmetric, and very narrow molecular weight distribution, the MBM copolymers synthesized with the m-DIB/t-BuLi diadduct are pure triblocks and show a high tensile strength, in contrast to copolymers initiated by the PEB/t-BuLi diadducts that are of a lower tensile strength and contaminated by MB diblock copolymers. Solvent cast films of MBM prepared with the m-DIB/t-BuLi diadduct are two-phase materials as confirmed by DSC and dynamic mechanical analysis (DMA). Transmission electron microscopy (TEM) shows a spherical morphology at a low sPMMA content, that changes into a cylindrical and finally lamellar morphology upon increasing the sPMMA content. Phase separation is observed for MBM with M̄n of the sPMMA blocks as low as 6000. Dependence of tensile strength on copolymer structure and sample preparation has been studied. The smaller sPMMA molecular weight, M̄n(PMMA), required for high tensile strength depends on the PBD molecular weight, M̄n(PBD), e.g. 12 000 for Mn(PBD) = 36 000 and 6000 for Mn(PBD) = 80 000. The upper M̄n(PMMA) is ca. 20−25 000, whatever the Mn(PBD). The optimum tensile strength is observed for M̄n(PMMA) = 15 000, independently of Mn(PBD) in the studied range. As a rule, the tensile strength tends to level off and the elongation at break starts to decrease when the sPMMA content is increased beyond 35 wt %. At a constant sPMMA content, Mn(PBD) (>ca. 36 000) does not affect the ultimate tensile properties. [less ▲]

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See detailMicrodomain morphology analysis of block copolymers by atomic force microscopy with phase detection imaging
Leclère, Philippe; Lazzaroni, Roberto; Brédas, Jean-Luc et al

in Langmuir (1996), 12(18), 4317-4320

We use atomic force microscopy (AFM) with phase detection imaging (PDI) in order to study the surface microdomain morphology of thick (i.e., ca. 2 mm) films of triblock copolymers. We present here the ... [more ▼]

We use atomic force microscopy (AFM) with phase detection imaging (PDI) in order to study the surface microdomain morphology of thick (i.e., ca. 2 mm) films of triblock copolymers. We present here the results obtained on a poly(methyl methacrylate)-block-polybutadiene-block-poly(methyl methacrylate) (PMMA-b-PBD-b-PMMA) copolymer prepared by using a 1,3-diisopropenylbenzene (DIB)-based difunctional anionic initiator. Our data illustrate the interest of PDI for the elucidation of surface phase separation in block copolymers. We show that the surface of thick films studied by this new technique exhibits a two-phase structure corresponding to the two types of components. [less ▲]

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See detailThe distribution of hot hydrogen atoms produced by electron and proton precipitation in the Jovian aurora
Bisikalo, D. V.; Shematovich, V. I.; Gérard, Jean-Claude ULg et al

in Journal of Geophysical Research (1996), 101

The energy distribution functions of nonthermal thermospheric hydrogen atoms are calculated for electron and proton precipitation in the Jovian aurora. A numerical model taking into account the production ... [more ▼]

The energy distribution functions of nonthermal thermospheric hydrogen atoms are calculated for electron and proton precipitation in the Jovian aurora. A numerical model taking into account the production, elastic and inelastic relaxation and transport processes for hot H atoms is developed. This model is based on a Monte Carlo solution of the nonlinear Boltzmann equation for hot H atoms produced by electron and proton impact on H and H[SUB]2[/SUB] and exothermic chemical reactions. The distribution functions show a much higher energy tail for proton than electron precipitation. It is shown that the steady state flux of hot atoms (E>=2 eV) is essentially isotropic. The peak and column hot H densities are about 3×10[SUP]5[/SUP] cm[SUP]-3[/SUP] and 1×10[SUP]14[/SUP] cm[SUP]-3[/SUP] for a 100 erg cm[SUP]-2[/SUP]s[SUP]-1[/SUP] precipitation combining hard (22 keV) and soft (0.2 keV) electrons mixed with a 10 erg cm[SUP]-2[/SUP]s[SUP]-1[/SUP] flux of soft (0.3 keV) protons. These column densities, coupled with the wide range of hot H atom energies, may play an important role in the formation of the Lyman alpha line profile. Multiple scattering in the wings of the Ly alpha line by the fast H atoms is shown to partly account for the broad Ly alpha profile observed in the Jovian aurora with the Hubble space telescope. [less ▲]

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See detailEffects of Schwann Cell Transplantation in a Contusion Model of Rat Spinal Cord Injury
Martin, Didier ULg; Robe, Pierre ULg; Franzen, Rachelle ULg et al

in Journal of Neuroscience Research (1996), 45(5), 588-597

Cultured Schwann cells were transplanted at various delays into a spinal cord contusion injury performed at low thoracic level in adult female rats. The Schwann cells were purified from the dorsal root ... [more ▼]

Cultured Schwann cells were transplanted at various delays into a spinal cord contusion injury performed at low thoracic level in adult female rats. The Schwann cells were purified from the dorsal root ganglia of adult syngeneic animals. the transplants were well tolerated, and the transplanted Schwann cells invaded the injured spinal cord. As quantified using video image analysis, the survival and growth of the transplanted cells were poor when the grafting procedure was performed 3-4 days after injury and very good when performed immediately or 10 days after injury, in which cases post-traumatic micro- and macrocavitation were strongly reduced. In animals grafted immediately after injury but not in animals grafted after 10 days, post-traumatic astrogliosis was much reduced. The Schwann cells transplanted area was invaded by numerous regenerating axons, the vast majority of which were, based on the neurotransmitter (CGRP and SP) profile, originating from dorsal root ganglion. No regeneration of the corticospinal tract as assessed after anterograde tracing or of descending aminergic fibers could be demonstrated. [less ▲]

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