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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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See detailPKS 1610-771: a highly reddened quasar?
Courbin, F.; Hutsemekers, Damien ULg; Meylan, G. et al

in The Messenger (1996), 85

Not Available

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See detailBinding of insertion/deletion DNA mismatches by the heterodimer of yeast mismatch repair protein MSH2 and MSH3
Habraken, Yvette ULg; Sung, Patrick; Prakash, Louise et al

in Current Biology (1996), 6(9), 1185-7

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See detailSimulations of the kinetic growth of YBa2Cu307-delta grains
Cloots, Rudi ULg; Vandewalle, Nicolas ULg; Ausloos, Marcel ULg

in Journal of Crystal Growth (1996), 166(1-4), 816-819

Using simple kinetic and geometric arguments, we have developed a computer model which simulates the growth of melt-textured YBa2Cu307-delta grains along the a-b planes. A chemical bonding anisotropy ... [more ▼]

Using simple kinetic and geometric arguments, we have developed a computer model which simulates the growth of melt-textured YBa2Cu307-delta grains along the a-b planes. A chemical bonding anisotropy along the main lattice directions is taken into account by the model. We have also considered the presence of Y2BaCu05 particles becoming trapped or not in the solidifying YBa2Cu307-delta front. The model simulates the fomation of 211 segregation patterns in the 123 matrix. An interpretation of these is attempted in terms of trapping anisotropy due to intrinsic crystallographic anisotropy. [less ▲]

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See detailTwo-component spreading phenomena: Why the geometry makes the criticality
Vandewalle, Nicolas ULg; Ausloos, Marcel ULg

in Physical Review. E : Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics (1996), 54(3), 3006-3008

We have numerically and theoretically investigated a simple model for two-component spreading phenomena in two different growth geometries (i.e., spreading confined in a half space and spreading in a free ... [more ▼]

We have numerically and theoretically investigated a simple model for two-component spreading phenomena in two different growth geometries (i.e., spreading confined in a half space and spreading in a free space). The criticality of the domain substructures unexpectedly depends on the considered geometry. This is understood by simple arguments of domain-wall particle diffusion and annihilation. We derive a relationship between the critical exponents chi and alpha for domain-wall spatial distributions in different geometries. The latter relationship is numerically verified in two, three and four dimensions. [less ▲]

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See detailFactor Xiiia-Positive Dendrocytes and Proliferative Activity of Cutaneous Cancers
Pierard-Franchimont, Claudine ULg; Arrese Estrada, Jorge ULg; Nikkels, Arjen ULg et al

in Virchows Archiv : An International Journal of Pathology (1996), 429(1), 43-48

Factor XIIIa-positive dendrocytes present at the periphery and inside epithelial neoplasms are an heterogeneous group of cells. They are subsets of mesenchymal cells, cancer-associated macrophages and ... [more ▼]

Factor XIIIa-positive dendrocytes present at the periphery and inside epithelial neoplasms are an heterogeneous group of cells. They are subsets of mesenchymal cells, cancer-associated macrophages and antigen-presenting cells. Factor XIIIa, other tissue transglutaminases, alpha 2-macroglobulin and tumour necrosis factor-alpha represent a complex network of mediators influencing tumour progression in the skin. In the present study we searched for the presence of dendrocytes and alpha 2-macroglobulin deposits inside and in the vicinity of cutaneous carcinomas (90 basal cell carcinomas and 46 squamous cell carcinomas) and malignant melanomas (69 primary and 28 metastatic tumours). We also studied the proliferation of the same neoplasms by Ki-67 immunohistochemistry. Dendrocytes were numerous, abutting on and infiltrating most basal cell carcinomas and thin malignant melanomas. In contrast, they were present in only low numbers or even absent in thick primary malignant melanomas and in their metastases. They appeared unmodified around squamous cell carcinomas compared with the surrounding skin. Extracellular deposits of alpha 2-macroglobulin were often found in locations where dermal dendrocytes were numerous. No correlation was found between the Ki-67 indices of carcinomas and the density of peritumoral dendrocytes. In contrast, negative relationships were found between the Ki-67 indices and the number of dendrocytes present inside basal cell carcinomas and thin malignant melanomas. This study has yielded circumstantial evidence to link the density of factor XIIIa-positive dendritic cells and a low proliferative rate of neoplastic cells in basal cell carcinomas and malignant melanomas. [less ▲]

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See detailThe non-penicillin-binding module of the tripartite penicillin-binding protein 3 of Escherichia Coli is required for folding and/or stability of the penicillin-binding module and the membrane-anchoring module confers cell septation activity on the folded structure
Goffin, Colette ULg; Fraipont, Claudine ULg; Ayala, Juan et al

in Journal of Bacteriology (1996), 178(18), 5402-5409

The ftsI-encoded multimodular class B penicillin-binding protein 3 (PBP3) is a key element of the cell septation machinery of Escherichia coli. Altered ftsI genes were overexpressed, and the gene products ... [more ▼]

The ftsI-encoded multimodular class B penicillin-binding protein 3 (PBP3) is a key element of the cell septation machinery of Escherichia coli. Altered ftsI genes were overexpressed, and the gene products were analyzed with respect to the level of production, stability, penicillin affinity, and cell septation activity. In contrast to the serine beta-lactamases and low-molecular-mass PBPs which are autonomous folding entities, the S-259-to-V-577 penicillin-binding module of M-1-to-V-577 PBP3 lacks the amino acid sequence information for correct folding. The missing piece of information is provided by the associated G-57-to-E-258 non-penicillin-binding module which functions as a noncleaved, pseudointramolecular chaperone. Key elements of the folding information reside within the motif 1-containing R-60-to-W-110 polypeptide segment and within G-188-to-D-197 motif 3 of the n-PB module. The intermodule interaction is discussed in the light of the known three-dimensional structure (at 3.5-A [0.35-nm] resolution) of the analogous class B PBP2x of Streptococcus pneumoniae (S. Pares, N. Mouz, Y. Petillot, R. Hakenbeck, and O. Dideberg, Nature Struct. Biol. 3:284-289, 1996). Correct folding and adoption of a stable penicillin-binding conformation are necessary but not sufficient to confer cell septation activity to PBP3 in exponentially growing cells. The in vivo activity of PBP3 also depends on the M-1-to-E-56 amino-terminal module which encompasses the cytosol, the membrane, and the periplasm and which functions as a noncleaved pseudo-signal peptide. [less ▲]

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See detailEffects of a reduction of nitrogen fertilizer on sward characteristics and dairy cows performances
Dufrasne, Isabelle ULg; Limbourg, Pierre; Hornick, Jean-Luc ULg et al

in Proceedings of the 16th General Meeting of the European Grassland Federation (1996)

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See detailLes niveaux de contamination par les métaux lourds chez deux espèces de Delphinidae: Stenella coeruleoalba et Delphinus delphis
Das, Krishna ULg

Master's dissertation (1996)

Les cétacés occupent le sommet des réseaux trophiques marins. Cette position, combinée à leur longue durée de vie et leur statut d’homéotherme favorise une accumulation de polluants dans leurs tissus ... [more ▼]

Les cétacés occupent le sommet des réseaux trophiques marins. Cette position, combinée à leur longue durée de vie et leur statut d’homéotherme favorise une accumulation de polluants dans leurs tissus (Bouquegneau et al., 1996). Ces animaux s’avèreraient donc d’excellents bioindicateurs potentiels, reflétant la contamination de leur environnement. Dans le cadre de cette étude, les niveaux de mercure total, de sélénium, de cadmium, de zinc, de nickel, de chrome, de plomb, de cuivre et de fer ont été évalués dans différents tissus prélevés sur des dauphins bleus et blancs (Stenella coeruleoalba) et des dauphins communs (Delphinus delphis) provenant du Golfe de Gascogne. Les influences combinées de l’âge, du sexe et du statut reproducteur ont été analysées. Les résultats obtenus lors de nos différentes analyses ont été également confrontés à ceux de la littérature afin de réaliser une comparaison avec d’autres sites. [less ▲]

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See detailMyorelaxant effects of 2-alkyl-substituted 2H-pyrido[4,3-e]-1,2,4-thiadiazine 1,1-dioxides
Pirotte, Bernard ULg; De Tullio, Pascal ULg; Ouedraogo, R. et al

Poster (1996, September)

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See detailProgress towards coumarinic derivatives as protease inhibitors
Doucet, C.; Pochet, L.; Schynts, M. et al

Poster (1996, September)

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See detailNeurotrophic Factors: Past and Future
Moonen, Gustave ULg; Malgrange, Brigitte ULg; Rigo, Jean Michel et al

in Acta Neurologica Belgica (1996), 96(3), 203-18

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See detailAnterior cingulate dysfunction in presenile dementia due to progressive supranuclear palsy
Salmon, Eric ULg; Meulemans, Thierry ULg; Van der Linden, Martial ULg et al

in Acta Neurologica Belgica (1996), 96(3), 247-253

We report neuropsychological and neuroimaging investigations performed in a patient suffering from presenile onset degenerative dementia and subsequent mild extrapyramidal and pyramidal signs. Early ... [more ▼]

We report neuropsychological and neuroimaging investigations performed in a patient suffering from presenile onset degenerative dementia and subsequent mild extrapyramidal and pyramidal signs. Early neuropsychological testing revealed frontal lobe dysfunction. Neuroanatomical pictures were not contributive. After four years of evolution, the clinical pattern was consistent with progressive supranuclear palsy. Statistical parametric mapping analysis of functional imaging revealed a highly significant metabolic impairment in the anterior cingulate gyrus, that might be a key feature of subcortico-frontal dementia in progressive supranuclear palsy. [less ▲]

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See detailIn Vivo Expression of Interleukin-1 Beta (Il-1 Beta), Il-2, Il-4, Il-6, Tumour Necrosis Factor-Alpha and Interferon-Gamma in the Fetal Murine Thymus
Deman, J.; Van Meurs, M.; Claassen, E. et al

in Immunology (1996), 89(1), 152-7

Cytokines are known to play a role in T-cell lymphopoiesis as potent growth or differentiation factors, but many experiments focusing on their role in the thymus have been conducted only in vitro. We have ... [more ▼]

Cytokines are known to play a role in T-cell lymphopoiesis as potent growth or differentiation factors, but many experiments focusing on their role in the thymus have been conducted only in vitro. We have thus used frozen sections obtained from fetal thymuses of normal C57BL 6 mice to investigate by immunohistochemistry the presence of interleukin-1 beta (I4-1 beta), IL-2. IL-4. IL-6. interferon-7 (IFN-7) and tumour necrosis facor-alpha (TNF-alpha). The results reveal that apart from IL-2, which was not detected, all these cytokines display a time-dependent expression pattern in the normal fetal thymus. First, production of IL-4, IL-6 and TNF-alpha is detected around days 13 14; this is followed by a second wave on days 16 17, with a production of IL-1 beta, IL-4 and IL-6, and finally, just before birth (day 19), by a third wave of IL-1 beta, IL-4, IL-6, IFN-7 and TNF-alpha production. This supports the hypothesis that cytokines play a rote in T-cell lymphopoiesis. [less ▲]

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