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See detailLA DÉGRADATION D’UN ÉCOSYSTÈME FORESTIER PÉRI-URBAIN : QUELS SONT LES PRINCIPAUX FILTRES À SA RÉGÉNÉRATION ?
Hick, Aurélie ULg; Tooth, Martin; Hallin, Maud et al

Poster (2013, December 19)

Au sud de la République Démocratique du Congo, dans la province du Katanga, le redéveloppement des activités minières a entrainé un développement démographique exponentiel des principales villes minières ... [more ▼]

Au sud de la République Démocratique du Congo, dans la province du Katanga, le redéveloppement des activités minières a entrainé un développement démographique exponentiel des principales villes minières. La population de Lubumbashi, capitale du Katanga, est passée en 50 ans d’environ 100 000 habitants à plus d’1 million et demi (Munyemba Kankumbi, 2010). Cette évolution démographique a accentué la pression sur la forêt claire de type Miombo par l’augmentation des prélèvements, la pression immobilière et l’agriculture de subsistance (Malaisse, 1997). Dans la zone périurbaine de Lubumbashi, les surfaces de forêts claires qui occupaient 85 % du territoire en 1956 ont été réduites à moins de 12 % en 2009 (Munyemba Kankumbi, 2010). Trois études ont été menées dans le but de caractériser les filtres écologiques et les filtres sociaux à la restauration de cet écosystème périurbaine. Les deux premières études ont pour objectif d’illustrer la diversité des communautés végétales du Miombo, leurs variations après dégradation le long d’un gradient forêt/savane sur les sols principaux de la plaine et les principaux filtres écologiques à sa régénération. 134 placettes forestières placées aléatoirement dans les derniers massifs forestiers présents dans un rayon de 50km autour de la ville ont été inventoriées. 53 placettes ont été placées sur trois sites choisis pour caractériser les communautés présentes le long du gradient de dégradation : forêts, forêts dégradées, savanes boisées, savanes arborées et savanes herbeuses. Au sein de ces placettes l’ensemble des espèces forestières ont été identifiées. Le sol a été caractérisé physiquement et chimiquement. La mesure de la biomasse herbacée a également été réalisée sur le gradient de dégradation. Les filtres sociaux ont été analysés aux travers de 35 enquêtes menées dans 4 villages de la plaine afin de comprendre leur mode d’agriculture, leur vision de l’arbre et la possibilité d’insérer un mode de culture de type agroforestier. Les grandes communautés caractéristiques de cet écosystème ont été mises en évidence, illustrant ainsi la richesse des dernières taches forestières présentes dans la plaine. Le type de sol est significativement corrélé à la répartition des communautés. Les essences présentes en savanes sont différentes de celles présentes en forêts pour un même type de sol. La biomasse herbacée est un filtre significatif à la régénération de la forêt favorisant la présence d’espèces tolérantes au feu. La modification des conditions chimiques du sol suite à la production de charbon de bois / agriculture n’est pas apparue comme un filtre majeur de la restauration. Les enquêtes nous ont permis de recenser une liste d’espèces utiles pour la production de charbon de bois, de bois de construction, etc d’après la vision des villageois. Néanmoins, les pratiques villageoises actuelles ne montrent pas d’intérêt à la préservation de ces espèces. Leur système de culture et leurs connaissances semblent tournés vers un mode culture de plus en plus intensif, mono-spécifique et tourné vers l’utilisation de fertilisants. Le problème majeur d’accès à la ressource en bois ne semble pas être dans la conscience de la population alors que la déforestation ne cesse de croitre. [less ▲]

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See detailDégradation de dalles de tablier de ponts en Belgique. Etude d'une pathologie complexe
Demars, Philippe; Gilles, Pierre; Darimont, Anne ULg

in Bulletin des Laboratoires des Ponts et Chaussées (2001), 232

Detailed reference viewed: 99 (2 ULg)
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See detailDégradation du cartilage et stress oxydatif chez des patients arthrosiques et souffrant d'arthrite rhumatoide
Deberg, Michelle; Labasse, A; Christgau, S et al

in Revue du Rhumatisme (2003), 70

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See detailDegradation inhibitors and metal additives: impact on solvent degradation
Léonard, Grégoire ULg

Report (2012)

This report is part of a PhD thesis currently taking place at the University of Liège in collaboration with the company Laborelec. A Degradation Test Rig (DTR) has been built in order to evaluate solvent ... [more ▼]

This report is part of a PhD thesis currently taking place at the University of Liège in collaboration with the company Laborelec. A Degradation Test Rig (DTR) has been built in order to evaluate solvent degradation in CO2 capture conditions. Details about degradation effects and about the DTR may be found in a previous report (PhD mid-term report, G. Léonard, 2011). Experiments to study the effect of process conditions on degradation are in progress with 2-ethanolamine (MEA) as benchmark solvent. This report presents first a brief overview of the different degradation mechanisms and associated products, followed by a literature review about metal influence on MEA degradation and a state of the art review about degradation inhibitors. [less ▲]

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See detailDegradation mechanisms of Prussian blue pigments in paint layers
Samain, Louise ULg

Doctoral thesis (2012)

Prussian blue is a modern synthetic pigment discovered in Berlin at the beginning of the eighteenth century. Prussian blue is a hydrated iron(III) hexacyanoferrate(II) complex and its color results from ... [more ▼]

Prussian blue is a modern synthetic pigment discovered in Berlin at the beginning of the eighteenth century. Prussian blue is a hydrated iron(III) hexacyanoferrate(II) complex and its color results from an intervalence charge transfer between the iron(II) and iron(III) ions when light is absorbed at ca. 700 nm. Because of both its highly intense color and its low cost, Prussian blue enjoyed immediate popularity among artists and was widely used as a pigment in paintings until the 1970's. However, the permanence of Prussian blue had already been questioned by the mid-eighteenth century, because it exhibits a tendency to fade in light and to turn green. The preparative methods were rapidly recognized as a contributory factor in the fading of the pigment. The main objective of this thesis is the identification of the degradation mechanisms of Prussian blue pigments in paint layers. Prussian blue was synthesized according to both ancient and modern preparation methods. A thorough analysis of the pigments revealed a dependency upon the type of synthesis, the crystallite size, and vacancy content, all properties that influence the local electronic and structural configurations of the iron ions in Prussian blue. The presence of nanocrystalline ferrihydrite as an undesirable iron containing reaction product was identified in Prussian blue pigments prepared according to eighteenth-century recipes. Discoloration upon light exposure in Prussian blue paint layers was induced by accelerated ageing. Pure Prussian blue painted in a dark shade is extremely light fast but fades when either painted in a lighter shade or mixed with white pigments. The fading of Prussian blue was attributed to a reduction of the iron(III) ions at the surface of the paint layer. A partial oxidation of Prussian blue in the entire paint layer was also observed. The analysis of works of art containing Prussian blue confirmed the combined oxidation and reduction of Prussian blue iron ions upon ageing. The study of alteration mechanisms in a painting pigment is essential both for conservation and historical studies in order to best preserve our cultural and artistic heritage with respect to an artist’s original intentions. [less ▲]

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See detailDegradation mechanisms of Pt/C electrocatalysts at the nm-scale
Maillard, F.; Vion-Dury; Solhy, K. et al

Conference (2009, May 24)

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See detailDegradation of benzylpenicillin by the exocellular DD-carboxypeptidase-transpeptidase from Streptomyces R 61
Frère, Jean-Marie ULg; Adriaens, P.; Degelaen, J. et al

in Archives Internationales de Physiologie et de Biochimie (1975), 83(5), 905-907

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See detailThe Degradation Of L-Tyrosine To Phenol And Benzoate In Pig Manure - The Role Of 4-Hydroxy-Benzoate
Antoine, P.; Taillieu, X.; Thonart, Philippe ULg

in Applied Biochemistry and Biotechnology (1997), 63-5

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See detailThe degradation of L-tyrosine to phenol and benzoate in pig manure. The role of 4-hydroxy-benzoate
Antoine, P.; Taillieu, X.; Verstraete, W. et al

Poster (1996, May)

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See detailDegradation of p-nitrophenol and bacteria with TiO2 xerogels sensitized in situ with tetra(4-carboxyphenyl)porphyrins
Tasseroul, Ludivine ULg; Lambert, Stéphanie ULg; Eskenazi, David et al

Poster (2015, September 10)

Heterogeneous photocatalysis is widely studied for environmental applications as oxidative processes can completely destroy organic pollutants such as alkanes, pesticides, dyes, etc. and microorganisms ... [more ▼]

Heterogeneous photocatalysis is widely studied for environmental applications as oxidative processes can completely destroy organic pollutants such as alkanes, pesticides, dyes, etc. and microorganisms. The most used photocatalyst is the commercial TiO2 Degussa P25, which is composed of 80% anatase and 20% rutile and which is active when TiO2 is exposed to UV light ( < 380 nm). Recently, several studies have been performed to extend the light absorption range of TiO2 towards the visible range. In this study, TiO2-based materials doped with porphyrins, a widely used dye for the photosensibilization of TiO2, have been prepared using a sol-gel process. To stabilize the TiO2-dye interactions, free metal tetra(4-carboxyphenyl)porphyrin and nickel tetra(4-carboxyphenyl)porphyrin were introduced in situ into the TiO2 matrix during the sol-gel process rather than by grafting. Samples were thoroughly characterized by TEM, X-ray diffraction, FT-IR, DR-UV/Vis and their texture has been examined by nitrogen adsorption–desorption at 77 K. The photocatalytic activity for the degradation of p-nitrophenol and Escherichia coli and Lactobacillus rhamnosus bacteria cells in aqueous medium, under halogen lamp light have been evaluated in relation with the physico-chemical modifications induced by the doping. The low temperature vacuum drying protocol (150°C) used in the present study enabled to obtain porphyrin doped TiO2 xerogels with a high specific surface area, and containing nanoparticles composed of amorphous- and anatase-TiO2. Diffuse reflectance spectroscopy attest the presence of TCPPH2 and TCPPNi within the TiO2 matrix. In a first step, the photoactivity of the xerogels is tested for p-nitrophenol degradation. Results show that crystallinity and nature and concentration of porphyrin introduced in situ have major impact on the degradation performances. In a second step, the best xerogel for p-nitrophenol degradation has been used to degrade bacteria. This xerogel degrades E. coli and L. rhamnosus bacteria cells in less than 48 and 24 h respectively. The photocatalytic degradation of a pollutant is thus correlated to the degradation of bacteria since a xerogel doped with the TCPPNi degrades both p-nitrophenol, E. coli and L. rhamnosus. [less ▲]

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See detailDegradation of p-nitrophenol and bacteria with TiO2 xerogels sensitized in situ with tetra(4-carboxyphenyl)porphyrins
Tasseroul, Ludivine ULg; Lambert, Stéphanie ULg; Eskenazi, David ULg et al

in Journal of Photochemistry and Photobiology A : Chemistry (2013), 272

TiO2-based materials doped with porphyrins have been prepared using a sol-gel process. To stabilize the TiO2-dye interactions, free metal tetra(4-carboxyphenyl)porphyrin and nickel tetra(4-carboxyphenyl ... [more ▼]

TiO2-based materials doped with porphyrins have been prepared using a sol-gel process. To stabilize the TiO2-dye interactions, free metal tetra(4-carboxyphenyl)porphyrin and nickel tetra(4-carboxyphenyl) porphyrin were introduced in situ into the TiO2 matrix during the sol-gel process rather than by grafting. Samples were thoroughly characterized by TEM, X-ray diffraction, FT-IR, DR-UV/vis and their texture has been examined by nitrogen adsorption-desorption at 77 K. The low thermal treatment allows obtaining anatase-TiO2 particles with high specific surface area without porphyrin degradation. A significant improvement of the photoactivity under visible light of porphyrin doped-TiO2 xerogels was observed for p-nitrophenol and for bacterial degradation. © 2013 Elsevier B.V. All rights reserved. [less ▲]

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See detailDegradation of recombinant IgG by root-secreted proteases of Arabidopsis thaliana and Nicotiana tabacum
Désiron, Carole ULg; Lallemand, Jérôme ULg; Périlleux, Claire ULg et al

Poster (2012, April 18)

Plants are promising hosts for the production of complex recombinant pharmaceuticals, such as antibodies (mAbs), because they offer an inexpensive and safer alternative to traditional production systems ... [more ▼]

Plants are promising hosts for the production of complex recombinant pharmaceuticals, such as antibodies (mAbs), because they offer an inexpensive and safer alternative to traditional production systems. The plant-based production of mAbs, which are multimeric glycoproteins, require their targeting to the secretory pathaway where they are properly folded and matured. However, co-secretion of endogenous proteases, which can represent up to 10% of the extracellular proteins (secretome), is known to significantly alter the yield and quality of secreted mAbs. In this study, we analyzed the proteolytic activities in root-secretome of Arabidopsis thaliana and Nicotiana tabacum. Root-secretomes were recovered by salt extraction and the protease activity was assayed in vitro or by zymography, in a range of pH. The relative contribution of protease classes was evaluated with specific inhibitors. [less ▲]

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See detailThe degradation of the bridge deck slabs in Belgium mainly involves alkali-aggregate reactions
Demars, Philippe; Gilles, Pierre; Dondonné, Eric et al

Scientific conference (2008, June)

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See detailDegradation of tyrosine and phenylalanine by anaerobic bacterial consortia.
Antoine, P.; Taillieu, X.; Jacques, Philippe ULg et al

Poster (1995, February)

Detailed reference viewed: 25 (1 ULg)
See detailDegradation of tyrosine in pig manure
Godefroid, J.; Antoine, P.; De Poorter, M. et al

Poster (1993, June)

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See detailDegradomic and yeast 2-hybrid inactive catalytic domain substrate trapping identifies new membrane-type 1 matrix metalloproteinase (MMP14) substrates: CCN3 (Nov) and CCN5 (WISP2).
Butler, Georgina S.; Connor, Andrea R.; Sounni, Nor Eddine ULg et al

in Matrix Biology (2016)

Members of the CCN family of matricellular proteins are cytokines linking cells to the extracellular matrix. We report that CCN3 (Nov) and CCN5 (WISP2) are novel substrates of MMP14 (membrane-type 1 ... [more ▼]

Members of the CCN family of matricellular proteins are cytokines linking cells to the extracellular matrix. We report that CCN3 (Nov) and CCN5 (WISP2) are novel substrates of MMP14 (membrane-type 1-matrix metalloproteinase, MT1-MMP) that we identified using MMP14 "inactive catalytic domain capture" (ICDC) as a yeast two-hybrid protease substrate trapping platform in parallel with degradomics mass spectrometry screens for MMP14 substrates. CCN3 and CCN5, previously unknown substrates of MMPs, were biochemically validated as substrates of MMP14 and other MMPs in vitro-CCN5 was processed in the variable region by MMP14 and MMP2, as well as by MMP1, 3, 7, 8, 9 and 15. CCN1, 2 and 3 are proangiogenic factors yet we found novel opposing activity of CCN5 that was potently antiangiogenic in an aortic ring vessel outgrowth model. MMP14, a known regulator of angiogenesis, cleaved CCN5 and abrogated the angiostatic activity. CCN3 was also processed in the variable region by MMP14 and MMP2, and by MMP1, 8 and 9. In addition to the previously reported cleavages of CCN1 and CCN2 by several MMPs we found that MMPs 8, 9, and 1 process CCN1, and MMP8 and MMP9 also process CCN2. Thus, our study reveals additional and pervasive family-wide processing of CCN matricellular proteins/cytokines by MMPs. Furthermore, CCN5 cleavage by proangiogenic MMPs results in removal of an angiogenic brake held by CCN5. This highlights the importance of thorough dissection of MMP substrates that is needed to reveal higher-level control mechanisms beyond type IV collagen and other extracellular matrix protein remodelling in angiogenesis. SUMMARY: We find CCN family member cleavage by MMPs is more pervasive than previously reported and includes CCN3 (Nov) and CCN5 (WISP2). CCN5 is a novel antiangiogenic factor, whose function is abrogated by proangiogenic MMP cleavage. By processing CCN proteins, MMPs regulate cell responses angiogenesis in connective tissues. [less ▲]

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See detailDegré d'atteinte nerveuse périphérique dans la SLA, la SLP et la maladie de Kennedy
WANG, François-Charles ULg; Le Forestier, Nadine; GERARD, Pascale ULg et al

in Neurophysiologie Clinique = Clinical Neurophysiology (2006)

Detailed reference viewed: 38 (2 ULg)