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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

Detailed reference viewed: 18 (2 ULg)
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)

Detailed reference viewed: 27 (6 ULg)
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)

Detailed reference viewed: 5 (0 ULg)
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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)
See detailThe Degree of Correlation of Jovian and Saturnian Auroral Emissions With Solar Wind Conditions
Clarke, J. T.; Nichols, J.; Gérard, Jean-Claude ULg et al

Conference (2008, December 01)

While the terrestrial aurorae are known to be driven primarily by the interaction of the Earth's magnetosphere with the solar wind, auroral emissions on Jupiter and Saturn are thought to be driven ... [more ▼]

While the terrestrial aurorae are known to be driven primarily by the interaction of the Earth's magnetosphere with the solar wind, auroral emissions on Jupiter and Saturn are thought to be driven primarily by internal processes, with the main energy source being the planets' rapid rotation. Limited evidence has suggested there might be some influence of the solar wind on Jupiter's aurorae, and indicated that auroral storms on Saturn can occur at times of solar wind pressure increases. To investigate in detail the dependence of auroral processes on solar wind conditions, a large campaign of observations of these planets has been undertaken using the Hubble Space Telescope, in association with measurements from planetary spacecraft and solar wind conditions both propagated from one AU and measured near each planet. The data indicate a consistent brightening of both the auroral emissions and Saturn Kilometric Radiation (SKR) at Saturn close in time to the arrival of solar wind shocks and pressure increases, consistent with a direct physical relationship between Saturnian auroral processes and solar wind conditions. This correlation has been strengthened by the final campaign observations in Feb. 2008. At Jupiter the situation is less clear, with increases in total auroral power seen near the arrival of solar wind forward shocks, while little increase has been observed near reverse shocks. In addition, auroral dawn storms have been observed when there was little change in solar wind conditions. The data are consistent with some solar wind influence on some Jovian auroral processes, while the auroral activity also varies independently of the solar wind. This extensive data set will serve to constrain theoretical models for the interaction of the solar wind with the magnetospheres of Jupiter and Saturn. [less ▲]

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See detailDegree of phosphorus saturation in agricultural loamy soils with a near-neutral pH
Renneson, Malorie ULg; Vandenberghe, Christophe ULg; Dufey, Joseph et al

in European Journal of Soil Science (2015), 66

The degree of phosphorus saturation (DPS) represents the ratio of sorbed phosphorus (P) to the P sorption capacity (PSC) of soils. In some countries, DPS is used to evaluate the risk of P loss and surface ... [more ▼]

The degree of phosphorus saturation (DPS) represents the ratio of sorbed phosphorus (P) to the P sorption capacity (PSC) of soils. In some countries, DPS is used to evaluate the risk of P loss and surface water eutrophication. This study investigated DPS measurement and prediction in neutral loamy soils fromWallonia, Belgium. A total of 57 agricultural topsoil samples subject to diverse P management were evaluated. No satisfactory relationship could be found between PSC determined by a one-point short-term isotherm in the laboratory and the sum of aluminium and iron extracted by oxalate (Alox +Feox). The equation PSC=a Alox +b pHw appeared to be more appropriate for estimating PSC in the soils studied. These soils had a near-neutral pH, and P fixation processes linked to the presence of calcium ions or carbonates were important. Comparisons of DPS with soil-test P and water-extracted P suggested that DPS could be a useful agronomic and/or environmental indicator. Our results also showed that DPS values between 20 and 30% corresponded to the agronomic optimum of soil P content. Consequently, DPS may be used as an indicator of P status in neutral soils, provided that the PSC assessment is adapted to the local soil characteristics. [less ▲]

Detailed reference viewed: 88 (18 ULg)