References of "2006"
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See detailAtmospheric Carbon Dioxide and Climate Over Phanerozoic Times
François, Louis ULg; Lefèbvre, Vincent; Goddéris, Yves et al

Conference (2006, December)

The atmospheric CO2 mixing ratio has fluctuated widely over the Phanerozoic, according to the estimates from available proxy records. Because atmospheric CO2 is a major greenhouse gas, these fluctuations ... [more ▼]

The atmospheric CO2 mixing ratio has fluctuated widely over the Phanerozoic, according to the estimates from available proxy records. Because atmospheric CO2 is a major greenhouse gas, these fluctuations should have led to significant climatic variations. The "classical" view is indeed that atmospheric CO2 has been the main driver of the Earth's climate history. On long-term time scales, the atmospheric CO2 level is the result of the balance between CO2 inputs from volcanoes or oxidation of old organic carbon (kerogen) in exposed rocks and outputs through silicate weathering or organic carbon deposition. Existing model reconstructions of the Phanerozoic history of atmospheric CO2 are based on such budgets. Recent data and model experiments currently challenge these models. First, the carbon cycle may be more complex than represented in the earliest models. In particular, silicate weathering depends on numerous factors, which are not obvious to model or are poorly known over the Phanerozoic. Mountain uplift is one such factor, which has been much debated in the last decade. Lithology is another example: basalts weather much more rapidly than other silicate rocks and the emplacement of large basaltic areas on the continents may trigger glaciations. Continental configuration is also more important than previously thought, as indicated by recent model experiments on super-continent fragmentation coupling geochemical and climate models. Problems of "classical" Phanerozoic CO2 models are also well illustrated by the fact that the most recent estimates of CO2 degassing show very little variation between the Cretaceous and the present, a period when large changes in CO2 have occurred, whereas degassing is the most important forcing of CO2 evolution in long-term carbon cycle models. Second, CO2 is not the only driver of climate evolution. This obvious fact has largely been forgotten in Phanerozoic studies. What the proxies tell us on paleo-atmospheric CO2 is not always in line with what we know about paleoclimatic records. For instance, the proxies suggest relatively high CO2 levels during the Late Ordovician glaciations. Similarly, the Late Jurassic now appears to be colder than earlier thought, while again proxies suggest high atmospheric CO2 at that time. The mid-Miocene climate warming, which occurs simultaneously with a drop in CO2, provides another example. This latter change in CO2 is unanimously reflected in all proxies and, so, this decoupling between CO2 and climate cannot arise from uncertainties on the reconstructed CO2 levels or from dating problems, as might be the case of the former two examples. Other climatic drivers than CO2 clearly need to be considered. In this respect, vegetation- climate feedbacks have been completely disregarded in long-term climatic studies. Cenozoic cooling is, however, accompanied by a progressive transition from closed forests to more widespread grasslands and deserts on the continental areas, a change which must have had major impacts on the surface albedo and the water cycle. [less ▲]

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See detailA global inventory of stratospheric chlorine in 2004
Nassar, Ray; Bernath, Peter; Boone, Christopher D. et al

in Journal of Geophysical Research. Atmospheres (2006), 111(D22), 22312

[1] Total chlorine (Cl-TOT) in the stratosphere has been determined using the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) measurements of HCl, ClONO2, CH3Cl, CCl4, CCl3F (CFC ... [more ▼]

[1] Total chlorine (Cl-TOT) in the stratosphere has been determined using the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) measurements of HCl, ClONO2, CH3Cl, CCl4, CCl3F (CFC-11), CCl2F2 (CFC-12), CHClF2 (HCFC-22), CCl2FCClF2 (CFC-113), CH3CClF2 (HCFC-142b), COClF, and ClO supplemented by data from several other sources, including both measurements and models. Separate chlorine inventories were carried out in five latitude zones (60 degrees - 82 degrees N, 30 degrees - 60 degrees N, 30 degrees S - 30 degrees N, 30 degrees - 60 degrees S, and 60 degrees - 82 degrees S), averaging the period of February 2004 to January 2005 inclusive, when possible, to deal with seasonal variations. The effect of diurnal variation was avoided by only using measurements taken at local sunset. Mean stratospheric Cl-TOT values of 3.65 ppbv were determined for both the northern and southern midlatitudes (with an estimated 1 sigma accuracy of +/- 0.13 ppbv and a precision of +/- 0.09 ppbv), accompanied by a slightly lower value in the tropics and slightly higher values at high latitudes. Stratospheric Cl-TOT profiles in all five latitude zones are nearly linear with a slight positive slope in ppbv/km. Both the observed slopes and pattern of latitudinal variation can be interpreted as evidence of the beginning of a decline in global stratospheric chlorine, which is qualitatively consistent with the mean stratospheric circulation pattern and time lag necessary for transport. [less ▲]

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See detailAnesthesia for emergency cesarean section: regional or general?
Brichant, Jean-François ULg

Conference (2006, November 30)

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See detailA global inventory of stratospheric fluorine in 2004 based on Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) measurements
Nassar, Ray; Bernath, Peter F.; Boone, Christopher D. et al

in Journal of Geophysical Research (2006), 111

Total fluorine (FTOT) in the stratosphere has been determined using Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) measurements of HF, COF2, COClF, CF4, CCl3F (CFC-11), CCl2F2 ... [more ▼]

Total fluorine (FTOT) in the stratosphere has been determined using Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) measurements of HF, COF2, COClF, CF4, CCl3F (CFC-11), CCl2F2 (CFC-12), CHClF2 (HCFC-22), CCl2FCClF2 (CFC-113), CH3CClF2 (HCFC-142b), CH2FCF3 (HFC-134a), and SF6. The retrieval of HFC-134a (CH2FCF3) from spaceborne measurements had not been carried out prior to this work. Measurements of these species have been supplemented by data from models to extend the altitude range of the profiles and have also been complemented by estimates of 15 minor fluorine species. Using these data, separate fluorine budgets were determined in five latitude zones (60°–82°N, 30°–60°N, 30°S–30°N, 30°–60°S, and 60°–82°S) by averaging over the period of February 2004 to January 2005 inclusive, when possible. Stratospheric FTOT profiles in each latitude zone are nearly linear, with mean stratospheric FTOT values ranging from 2.50 to 2.59 ppbv (with a 1sig precision of 0.04–0.07 ppbv and an estimated accuracy of 0.15 ppbv) for each zone. The highest mean FTOT value occurred in the tropics, which is qualitatively consistent with increasing levels of stratospheric fluorine and the mean stratospheric circulation pattern. [less ▲]

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See detailSynthesis and radioligand binding studies of methoxylated 1,2,3,4-tetrahydroisoquinolinium derivatives as ligands of the apamin-sensitive Ca2+- activated K+ channels
Graulich, Amaury ULg; Scuvée-Moreau, Jacqueline ULg; Alleva, Livia ULg et al

in Journal of Medicinal Chemistry (2006), 49(24), 7208-7214

Several methoxylated 1,2,3,4-tetrahydroisoquinoliniums derived from N-methyl-laudanosine and N-methyl-noscapine were synthesized and evaluated for their affinity for apamin-sensitive binding sites. The ... [more ▼]

Several methoxylated 1,2,3,4-tetrahydroisoquinoliniums derived from N-methyl-laudanosine and N-methyl-noscapine were synthesized and evaluated for their affinity for apamin-sensitive binding sites. The quaternary ammonium derivatives have a higher affinity with regard to the tertiary amines. 6,7-Dimethoxy analogues possess a higher affinity than the 6,8- and 7,8- dimethoxy isomers. A 3,4-dimethoxybenzyl or a 2-naphthylmethyl moiety in C-1 position are more favorable than a 3,4-dimethoxyphenethyl group. Smaller groups such as propyl or isobutyl are unfavorable. In 6,7-dimethoxy analogues, increasing the size and lipophilicity with a naphthyl group in the C-1 position leads to a slight increase of affinity, while the same group in the 6,7,8- trimethoxy series is less favorable. The 6,7,8- trimethoxy derivative 3f is the first tertiary amine in the series to possess an affinity close to that of N-methyl-laudanosine and N-methyl-noscapine. Moreover, electrophysiological studies show that the most effective compound 4f blocks the apamin-sensitive afterhyperpolarization in rat dopaminergic neurons. [less ▲]

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See detailNF-kappa B activation by reactive oxygen species: Fifteen years later
Gloire, Geoffrey ULg; Legrand-Poels, Sylvie ULg; Piette, Jacques ULg

in Biochemical Pharmacology (2006), 72(11), 1493-1505

The transcription factor NF-kappa B plays a major role in coordinating innate and adaptative immunity, cellular proliferation, apoptosis and development. Since the discovery in 1991 that NF-kappa B maybe ... [more ▼]

The transcription factor NF-kappa B plays a major role in coordinating innate and adaptative immunity, cellular proliferation, apoptosis and development. Since the discovery in 1991 that NF-kappa B maybe activated by H(2)o(2), several laboratories have put a considerable effort into dissecting the molecular mechanisms underlying this activation. Whereas early studies revealed an atypical mechanism of activation, leading to I kappa B alpha Y42 phosphorylation independently Of I kappa B kinase (IKK), recent findings suggest that H2O2 activates NF-kappa B mainly through the classical IKK-dependent pathway. The molecular mechanisms leading to IKK activation are, however, cell-type specific and will be presented here. In this review, we also describe the effect of other ROS (HOCl and O-1(2)) and reactive nitrogen species on NF-kappa B activation. Finally, we critically review the recent data highlighting the role of ROS in NF-kappa B activation by proinflammatory cytokines (TNF-alpha and IL-1 beta) and lipopolysaccharide (LPS), two major components of innate immunity. (c) 2006 Elsevier Inc. All rights reserved. [less ▲]

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See detailStructural and electrical properties of tellurovanadate glasses containing Li2O
Krins, Natasha ULg; Rulmont, André ULg; Grandjean, Jean ULg et al

in Solid State Ionics (2006), 177(35-36 Sp. Iss. SI), 3147-3150

Glassy materials are promising intercalation compounds, due to their open network structure and absence of grain boundaries. Some glasses containing alkali ions and a high concentration of transition ... [more ▼]

Glassy materials are promising intercalation compounds, due to their open network structure and absence of grain boundaries. Some glasses containing alkali ions and a high concentration of transition metal ions can present mixed ionic-electronic conductivity and are therefore potential candidates for application as cathode material in Li-ion batteries. The present work is devoted to the ternary system xLi(2)O-(1-x)[0.3V(2)O(5)-0.7TeO(2)] with 0 <= x <= 0.4. These compounds were prepared by heat treatment in air at 800 degrees C followed by traditional quenching. Raman spectroscopy and V-51 nuclear magnetic resonance measurements were performed in order to highlight the structural short range order modifications induced by the introduction of the Li2O network modifier. These structural effects can be related to the electrical behaviour, as studied by complex impedance spectroscopy measurements. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailPotentiation of cyclophosphamide chemotherapy using the anti-angiogenic drug thalidomide: Importance of optimal scheduling to exploit the ‘normalization’ window of the tumor vasculature
SEGERS, Jerome; DI FAZIO, Vincent; ANSIAUX, Reginald et al

in Cancer Letters (2006), 244(1), 12935

The aim of this work was to study how administration schedule affects potentiation of cyclophosphamide, an alkylating agent, by thalidomide, an anti-angiogenic agent. Tumor oxygenation after thalidomide ... [more ▼]

The aim of this work was to study how administration schedule affects potentiation of cyclophosphamide, an alkylating agent, by thalidomide, an anti-angiogenic agent. Tumor oxygenation after thalidomide administration was determined over time by EPR oximetry. Such measurements provide a surrogate marker for determining the timing of ‘normalization’ of tumor vasculature. Re-growth delays were measured using different combinations and schedules of treatments. Additionally, the uptake of the metabolite of cyclophosphamide (hydroxycyclophosphamide or OH-CP) into tumors was determined by high performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). A significant increase in pO2 was observed after 2 and 3 days of treatment before eventually declining on day 4. Thalidomide potentiated the effect of cyclophosphamide only when cyclophosphamide was administered after 2 days of treatment with thalidomide (no significant benefit using other schedules). In this time frame, the HPLC/MS/MS measurements showed that the quantity of OH-CP penetrating into the tumor was about twice in mice treated by thalidomide compared to controls. In conclusion, the present study demonstrates that the benefit of combined therapy using an anti-angiogenic agent with a cytotoxic agent requires knowledge of the time window during which the vessels initially become normalized. [less ▲]

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See detailCobalt-mediated radical polymerization (CMRP) of vinyl acetate initiated by redox systems: Toward the scale-up of CMRP
Bryaskova, Rayna ULg; Detrembleur, Christophe ULg; Debuigne, Antoine ULg et al

in Macromolecules (2006), 39(24), 8263-8268

A redox initiating system was developed in order to bypass 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (V70) as the initiator of the cobalt-mediated radical polymerization (CMRP) of vinyl acetate ... [more ▼]

A redox initiating system was developed in order to bypass 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (V70) as the initiator of the cobalt-mediated radical polymerization (CMRP) of vinyl acetate (VAc) in the presence of cobalt(II) acetylacetonate (Co(acac)(2)). It is indeed a problem to stock up with V70 because of needed storage at -20 degrees C during transportation. This paper reports on the controlled CMRP of VAc initiated by ascorbic acid combined with either lauroyl peroxide or benzoyl peroxide at 30 degrees C. Substitution of citric acid for ascorbic acid results in faster polymerization whereas the polymerization control is maintained. All these improvements facilitate the implementation of the vinyl acetate CMRP and open the door to the scale-up of the process. [less ▲]

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See detailLe théâtre de Denis Marion
Delhalle, Nancy ULg

Conference (2006, November 28)

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See detailInnovations pédagogiques et utiliation des NTIC dans le cadre de la formulation des aliments complets
Malumba Kamba, Paul ULg; Masimango, Thaddée

in Kechaou, Mohamed (Ed.) Actes du séminaire régional sur les Technologies douces et procédés de séparation au service de la qualité et de l'innocuité des aliments ’ (2006, November 27)

Des nombreuses approches d’optimisation des formulations ont été développées ces dernières années et commercialisées sous forme de logiciels dont les bases d’application restent méconnues de nombreux ... [more ▼]

Des nombreuses approches d’optimisation des formulations ont été développées ces dernières années et commercialisées sous forme de logiciels dont les bases d’application restent méconnues de nombreux praticiens. Dans la présente étude des fondements de la formulation conceptuelle des aliments utilisant les NTIC sont présentés et appliqués à un cas de formulation d’un aliment de croissance pour pondeuse. La validation de la formulation conceptuelle est obtenue grâce à l’analyse de la composition d’un aliment réel préparé suivant le modèle défini. Cet aliment est comparé avec un aliment équivalent de commerce [less ▲]

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See detailInfluence de la température de séchage sur les propriétés physicochimiques des amidons de maïs
Malumba Kamba, Paul ULg; Deroanne, Claude; Masimango, Thaddée et al

in Kechaou (Ed.) Actes du Séminaire d'animation régionale sur les Technologies douces et les procédés de séparation au service de la qualité et de l'innocuité des aliments (2006, November 27)

Les amidons extraits des grains de maïs séchés aux températures de l’air comprises entre 54 et 130°C ont été caractérisés par Analyse Calorimétrique Différentielle (ACD), par granulométrie laser, par ... [more ▼]

Les amidons extraits des grains de maïs séchés aux températures de l’air comprises entre 54 et 130°C ont été caractérisés par Analyse Calorimétrique Différentielle (ACD), par granulométrie laser, par microscopie sous lumière polarisée et par diffraction des rayons-X. Il ressort de cette étude que le séchage aux températures élevées induit une modification des propriétés intrinsèques des amidons sans pour autant induire leur gélatinisation complète [less ▲]

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See detailMémoire de travail et vieillissement pathologique
Adam, Stéphane ULg

Conference (2006, November 26)

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See detailNatural and projectively equivariant quantizations
Radoux, Fabian ULg

Conference (2006, November 25)

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See detailEtude en temps réel du processus d'extraction de la tagitinine C en fonction des caractéristiques physico-chimiques du CO2 supercritique à l'aide de fibres optiques couplant un spectrophotomètre IRTF à un extracteur à fluide supercritique
Ziemons, Eric ULg

Doctoral thesis (2006)

L’extraction par fluide supercritique fait partie des nouvelles techniques de préparation d’échantillons solides qui ont émergé au cours de ces dernières années. Elle constitue une alternative ... [more ▼]

L’extraction par fluide supercritique fait partie des nouvelles techniques de préparation d’échantillons solides qui ont émergé au cours de ces dernières années. Elle constitue une alternative intéressante aux techniques classiques d’extraction liquide-solide car le pouvoir solvant du fluide supercritique est ajustable, non seulement par la température, mais aussi par la pression. L’extraction par le CO2 supercritique de la tagitinine C, lactone sesquiterpénique photo sensible à l’activité anti-inflammatoire, anti-malarique et anticancéreuse à partir des parties aériennes de Tithonia diversifolia constituait une application intéressante de ce procédé et a été sélectionnée comme molécule cible dans le cadre de ce travail. Son optimisation a impliqué des dosages répétés de l’analyte dont la vibration d’élongation de la fonction diénone absorbe intensément à des fréquences particulières dans le domaine de l’infrarouge. Aussi, avons-nous tout d’abord développé et validé, dans la première partie de ce travail, une technique IRTF d’analyse en différé sélective, rapide, non destructrice et sensible fondée sur ses propriétés. Les différents paramètres (température, pression, quantité de CO2, granulométrie de l’échantillon) influençant le rendement d’extraction de l’analyte ont pu être étudiés à cette occasion. Dans les conditions optimales, nous avons montré que l’extraction par le CO2 supercritique extrayait rapidement et avec une meilleure sélectivité la tagitinine C tout en conservant un taux de récupération comparable aux techniques classiques d’extraction. Parallèlement à ces travaux et compte tenu de la photo-dégradation de la tagitinine C en tagitinine F, la formation de complexes d’inclusion avec la β, 2,6-di-O-méthyle-β et la -cyclodextrine a été investiguée. Différentes techniques ont été employées pour caractériser les complexes formés au niveau de la stœchiométrie, de la constante de formation et de la structure. Aucun effet photo-protecteur significatif n’a été démontré avec la β et la -cyclodextrine. En revanche, nous avons mis en évidence une diminution de la vitesse de la photo-dégradation en présence de la 2,6-di-O-méthyle-β-cyclodextrine. Malheureusement, celle-ci reste trop limitée pour envisager l’utilisation de cette cyclodextrine pour éviter la dégradation de la tagitinine C lors de son exposition à la lumière directe. Dans la dernière partie de notre travail, nous nous sommes plus particulièrement focalisés sur l’interfaçage EFSC/IRTF qui constituait un indéniable défi. Le développement de l’interfaçage a été réalisé à l’aide de fibres optiques en chalcogène d’arsenic entre un extracteur à fluide supercritique et un spectrophotomètre IR et a ainsi permis d’effectuer le dosage en ligne de la tagitinine C dans le CO2 supercritique après passage de celui-ci au travers d’une cartouche d’extraction contenant la matrice végétale. Par ailleurs, le développement de cet outil répond parfaitement aux nouvelles approches (Process and Analytical Technology) préconisées par la FDA. Le processus d’extraction de l’analyte a pu dès lors être étudié de manière approfondie et en temps réel en fonction des caractéristiques physico-chimiques du fluide supercritique et de la durée de l’extraction. L’utilisation de la vibration d’élongation CH comme marqueur a permis de mettre en évidence l’obtention d’extraits de composition variable qui pourront être utilisés directement dans des études d’efficacité thérapeutique. Enfin, la méthode d’extraction et de dosage en ligne de la tagitinine C a fait l’objet d’une validation poussée selon la nouvelle approche faisant appel aux profils d’exactitude dans un intervalle de dosage allant 500 à 2500 µg. Sur la base des différents profils d’exactitude obtenus, le modèle de régression linéaire a été choisi pour décrire la relation concentration-réponse. En effet, ce modèle présentait des valeurs de biais relatif inférieures à 2%, des valeurs de coefficient de variation ne dépassant pas 4% et des limites de tolérance comprises dans les limites d’acceptation de ±15% sur toute la gamme de concentration. De plus, le modèle de régression linéaire était en parfaite adéquation avec la méthode des ajouts dosés. [less ▲]

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See detailQuantifications naturelles projectivement équivariantes
Radoux, Fabian ULg

Doctoral thesis (2006)

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See detailL’autre et le même. Position du sujet et politique du corps
Durand, Pascal ULg

Conference (2006, November 24)

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