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See detailEsquisse des représentations collectives kimbanguistes De 1921 à nos jours
Melice, Anne ULg

Master's dissertation (1997)

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See detailEsquisse géologique du bassin de la Basse Lesse
Boulvain, Frédéric ULg

in Atlas du karst wallon: bassin de la Basse Lesse (2014)

Detailed reference viewed: 9 (0 ULg)
See detailEsquisse pour une généalogie des rapports entre droit et régulation
Thirion, Nicolas ULg

in Depré, Sébastien; Mourlon Beernaert (Eds.) Du monopole à la concurrence: quelle régulation? (2010)

Etude visant à retracer les différents sens du mot "régulation" dans le discours juridique des vingt dernières années et à dégager leur origine commune dans la pensée ordo-libérale allemande

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See detailEsquivanne: Un Outil de Conception des Barrages Mobiles de Navigation
Rigo, Philippe ULg; Lizin, S.; Closset, M. P. et al

in PIANC 2006, 31ème Congrès de l’PIANC (Article 076) (2006, May)

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See detailESR associated with spin-labelling methods into the study of photosensitization in liposomal solutions
Hoebeke, Maryse ULg

in Bulletin de la Société Royale des Sciences de Liège (2000)

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See detailESR evidence of superoxide anion, hydroxyl radical and singlet oxygen generation during photosensitization of PPME in HCT-116 cells
Quoilin, Caroline ULg; Guelluy, Pierre-Henri ULg; Grammenos, Angeliki ULg et al

Poster (2010, March)

Pyropheophorbide-a methyl ester (PPME), a derivative of chlorophyll a, is a second-generation photosensitizer and is studying largely in vitro for nearly a decade on cancerous cells. It has been ... [more ▼]

Pyropheophorbide-a methyl ester (PPME), a derivative of chlorophyll a, is a second-generation photosensitizer and is studying largely in vitro for nearly a decade on cancerous cells. It has been previously established on HCT-116 (human colon carcinoma cell line) that PPME is a molecule able to create apoptotic and necrotic death (Matroule et al). The cytotoxicity of PPME is presumed to be induced by reactive oxygen species (ROS) generated by the photoexcited molecule. Actually, to the best of our knowledge, no experimental evidence enables to confirm this supposition in an indubitable manner. Electron spin resonance (ESR) associated with spin trapping technique is a powerful method to detect, quantify and identify the ROS produced after photoactivation of PPME. Previous results indicate that PPME penetrates inside cells and localizes inside specific organelles (endothelial reticulum, Golgi apparatus and lysosome) (Matroule et al). The recent researches of Guelluy et al have also clearly demonstrated the presence of PPME inside mitochondrion. Consequently, ESR experiments were performed using an intracellular located spin trap, POBN (4-pyridyl 1-oxide-N-tert-butylnitrone), in order to detect in situ the ROS production. It has been shown that PPME is able to generate superoxide anions and hydroxyl radicals. Irradiation of the dye in HCT-116 cells in the presence of POBN spin trap and ethanol scavenger (2%, a non-toxic concentration) leads to the apparition of the ESR spectrum characteristics of POBN/ethoxy adduct. To assess the extent of contribution of ROS and to determine a possible reaction mechanism, competition experiments with specific quencher agents were carried out. Addition of catalase (CAT), a hydrogen peroxide quencher, or superoxide dismutase (SOD), a superoxide anion quencher, inhibits 30% of the signal. The parallel effect of SOD and CAT suggest that superoxide anion and hydrogen peroxide are involved in the generation of hydroxyl radicals via a Fenton reaction. This assertion is reinforced by the 20% reduction of signal intensity when adding desferroxamine, a Fe3+ chelator also implicated in Fenton reaction. Addition of DABCO, a quencher of singlet oxygen, to cells reduces 70% of the POBN/ethoxy adduct signal intensity. [less ▲]

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See detailESR Investigation of Chemical Exchange in Geminally Diphosphorylated Linear Nitroxide Radicals
Rockenbauer, Antal; Olive, Gilles ULg; Rozanska, Xavier et al

in Journal of Physical Chemistry A (2004), 108(25), 5484-5489

For geminally diphosphorylated linear nitroxide radicals, a marked line width alternation (LWA) can be observed. The LWA appears irrespectively whether the investigated radicals R¢¢N(O¥)C(P(O)(OEt)2)2R¢ ... [more ▼]

For geminally diphosphorylated linear nitroxide radicals, a marked line width alternation (LWA) can be observed. The LWA appears irrespectively whether the investigated radicals R¢¢N(O¥)C(P(O)(OEt)2)2R¢ contain any chiral group or not. If R¢¢ ) tert-butyl and R¢ ) H, the small â-hydrogen coupling indicates a completely blocked rotation around the N-C ó-bond and the LWA can be assigned to a chemical exchange between conformations in which the phosphoryl groups have a symmetric and a nonsymmetric geometry. The conformational change is accompanied by the deformation of the CP2 bonding angle and the rate of exchange is slowed in pentane for which the solvent molecules can be trapped by the chelating phosphoryl groups. If R¢¢ ) benzyl, both the proton hyperfine lines of the CH2 group and the phosphorus lines of the CP2 group produce a LWA; two coalescences can be observed. In the case of a chiral R¢¢ group (R¢¢ ) secondary butyl, R¢ ) methyl) a tentative four-site model can explain the highly complex LWA. [less ▲]

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See detailESR spectroscopy for the study of an inflammation-induced AKI cellular model
Quoilin, Caroline ULg; Mouithys-Mickalad, Ange ULg; Gallez, Bernard et al

Poster (2012, November)

The kidney is faced to an impairment of oxygen extraction during sepsis which is well-known to be a risk factor for the development of acute kidney injury (AKI). Recent research activities in the ... [more ▼]

The kidney is faced to an impairment of oxygen extraction during sepsis which is well-known to be a risk factor for the development of acute kidney injury (AKI). Recent research activities in the mechanisms involved in the development of AKI in sepsis emphasize the central role of hemodynamic and inflammatory events. More particularly, two mechanisms are suggested to explain the inability of the injured kidney to extract oxygen: tissue hypoxia and cellular energetic metabolism dysfunction. Our working hypothesis of the pathophysiology of AKI is based on cellular respiratory dysfunction due to the inflammatory response inherent to sepsis. To study the mechanism of oxygen regulation in inflammation-induced acute kidney injury, we investigate the effects of a bacterial endotoxin (lipopolysaccharide, LPS) on the basal respiration of proximal tubular epithelial cells (HK-2) by ESR oximetry. This method has shown that HK-2 cells exhibit a decreased oxygen consumption rate when treated with LPS. Surprisingly, this cellular respiration alteration persists even after the stress factor was removed. We suggested that this irreversible decrease in renal oxygen consumption after LPS challenge is related to a pathologic metabolic down-regulation such as a lack of oxygen utilization by cells. This decrease was accompanied by increased nitric oxide (NO) production as measured by a spin trapping technique using ESR spectroscopy. This method is based on the trapping of NO by a metal-chelator complex consisting of N-methyl-D-glucamine dithiocarbamate (MGD) and reduced iron (Fe2+) forming a water-soluble NO-FeMGD complex detected by ESR. Since inducible NO synthase (iNOS) has been shown to play an important role in sepsis-induced AKI, the iNOS inhibitor L-NMMA (L-NG-monomethyl Arginine citrate) was tested in this in vitro model. L-NMMA blocked NO generation and permitted the HK-2 cells to recover a normal cellular respiration. Overall, ESR spectroscopy and the model of HK-2 cells exposed to LPS displays some key features of inflammation-induced acute kidney injury. [less ▲]

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See detailESR studies of the in-situ nitroxide-mediated polymerization (NMP) of styrene using a nitrone
Sciannamea, Valérie; Bernard, M.; Catala, J.-M. et al

Conference (2004, November 26)

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See detailESR study of Bacteriochlorin a incorporation into membranes models
Hoebeke, Maryse ULg

Scientific conference (1999)

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See detailESR technique for non invasive way to quantify cyclodextrins effect on cell membranes
Grammenos, Angeliki ULg; Mouithys-Mickalad, Ange ULg; Guelluy, Pierre-Henri ULg et al

in Biochemical and Biophysical Research Communications (2010)

A new way to study the action of cyclodextrin was developed to quantify the damage caused on cell membrane and lipid bilayer. The Electron Spin Resonance (ESR) spectroscopy was used to study the action of ... [more ▼]

A new way to study the action of cyclodextrin was developed to quantify the damage caused on cell membrane and lipid bilayer. The Electron Spin Resonance (ESR) spectroscopy was used to study the action of Randomly methylated-beta-cyclodextrin (Rameb) on living cells (HCT-116). The relative anisotropy observed in ESR spectrum of nitroxide spin probe (5-DSA and cholestane) is directly related to the rotational mobility of the probe,which can be further correlated with themicroviscosity. The use of ESR probes clearly shows a close correlation between cholesterol contained in cells and cellular membrane microviscosity. This study also demonstrates the Rameb ability to extract cholesterol and phospholipids in time- and dose-dependent ways. In addition, ESR spectra enabled to establish that cholesterol is extracted from lipid rafts to form stable aggregates. The present work supports that ESR is an easy, reproducible and noninvasive technique to study the effect of cyclodextrins on cell membranes. [less ▲]

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