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See detailLower Devonian spores from South Wales.
Chaloner, W.G.; Streel, Maurice ULg

in Argumenta Palaeobotanica (1968), 1

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See detailLower Devonian spores from the Ardennes-Rhine area
Steemans, Philippe ULg

Conference (1984)

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See detailLower impact of blue light on non-visual brain functions in older subjects
Daneault, V; Vandewalle, Gilles ULg; Hébert, M et al

Poster (2012, February)

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See detailLower intracellular concentration of cryoprotectants after vitrification than after slow freezing despite exposure to higher concentration of cryoprotectant solutions.
Vanderzwalmen, P.; Connan, Delphine ULg; Grobet, Luc ULg et al

in Human reproduction (Oxford, England) (2013)

STUDY QUESTION: What is the intracellular concentration of cryoprotectant (ICCP) in mouse zygotes during vitrification (VIT) and slow-freezing (SLF) cryopreservation procedures? SUMMARY ANSWER: Contrary ... [more ▼]

STUDY QUESTION: What is the intracellular concentration of cryoprotectant (ICCP) in mouse zygotes during vitrification (VIT) and slow-freezing (SLF) cryopreservation procedures? SUMMARY ANSWER: Contrary to common beliefs, it was observed that the ICCP in vitrified zygotes is lower than after SLF, although the solutions used in VIT contain higher concentrations of cryoprotectants (CPs). WHAT IS KNOWN ALREADY: To reduce the likelihood of intracellular ice crystal formation, which has detrimental effects on cell organelles and membranes, VIT was introduced as an alternative to SLF to cryopreserve embryos and gametes. Combined with high cooling and warming rates, the use of high concentrations of CPs favours an intracellular environment that supports and maintains the transition from a liquid to a solid glass-like state devoid of crystals. Although the up-to-date publications are reassuring in terms of obstetric and perinatal outcomes after VIT, a fear about exposing gametes and embryos to high amounts of CPs that exceed 3-4-fold those found in SLF was central to a debate initiated by advocates of SLF procedures. STUDY DESIGN, SIZE, DURATION: Two experimental set-ups were applied. The objective of a first study was to determine the ICCP at the end of the exposure steps to the CP solutions with our VIT protocol (n = 31). The goal of the second investigation was to compare the ICCP between VIT (n = 30) and SLF (n = 30). All experiments were performed in triplicates using mouse zygotes. The study took place at the GIGA-Research Institute of the University of Liege. PARTICIPANTS/MATERIALS, SETTING, METHODS: Cell volume is modified by changes in extracellular osmolarity. Hence, we estimated the final ICCP after the incubation steps in the VIT solutions by exposing the cells to sucrose (SUC) solutions with defined molarities. The ICCP was calculated from the SUC concentration that produced no change in cell volume, i.e. when intra- and extracellular osmolarities were equivalent. Cell volume was monitored by microscopic cinematography. ICCP was compared between SLF and VIT based on the principle that a high ICCP lowers the probability of (re)crystallization during warming but increases the probability of over-swelling of the cell due to fast inflow of water. The survival rates of mouse zygotes after SLF or VIT were compared using either (i) various warming rates or (ii) various concentrations of SUC in the warming dilution medium. MAIN RESULTS AND THE ROLE OF CHANCE: The ICCP in mouse zygotes during the VIT procedure prior to plunging them in liquid nitrogen was approximately 2.14 M, i.e. one-third of the concentration in the VIT solution. After SLF, the warming rate did not affect the zygote survival rate. In contrast, only 3/30 vitrified zygotes survived when warmed slowly but as many as 30/30 zygotes survived when warming was fast (>20 000 degrees C/min). Vitrified zygotes showed significantly higher survival rates than slow-frozen zygotes when they were placed directly in the culture medium or in solutions containing low concentrations of SUC (P < 0.01). These two experiments demonstrate a lower ICCP after VIT than after SLF. LIMITATIONS, REASONS FOR CAUTION: The results should not be directly extrapolated to other stages of development or to other species due to possible differences in membrane permeability to water and CPs. WIDER IMPLICATIONS OF THE FINDINGS: The low ICCP we observed after VIT removes the concern about high ICCP after VIT, at least in murine zygotes and helps to explain the observed efficiency and lack of toxicity of VIT. STUDY FUNDING / COMPETING INTEREST(S): The study was funded by the FNRS (National Funds for Scientific Research). The authors declare that they have no competing interests. [less ▲]

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See detailLower Palaeozoic and Devonian carbonate facies in Nepal
Pas, Damien ULg; Boulvain, Frédéric ULg

Poster (2009, September 14)

Nepal is localized in the central part of the Himalayan arc. In uplift since the Cenozoic time, the Himalaya is traditionally divided into six lithotectonic zones extending in parallel belts. From north ... [more ▼]

Nepal is localized in the central part of the Himalayan arc. In uplift since the Cenozoic time, the Himalaya is traditionally divided into six lithotectonic zones extending in parallel belts. From north to south there are respectively: (1) the Trans-Himalayan batholith; (2) the Indus-Tsangpo suture zone; (3) the Tethyan (Tibetan) Himalaya; (4) the Higher (Greater) Himalaya; (5) the Lesser Himalaya; and (6) the Sub-Himalaya. This PhD thesis is focused on the Tethyan sedimentary rocks exposed in the Nepal Tethyan Himalaya belt and in the thrusting nappes belonging to the Lesser Himalaya. These nappes contain unmetamorphosed sedimentary rocks which might belong to the Tethyan sedimentary succession. The Tethyan Himalaya has preserved highly fossiliferous marine rocks deposited on the shelf and slope of the Indian continental margin from Late Proterozoic-Cambrian through early Eocene times. The main objective of this PhD thesis is to build a first sedimentological canvas for the Lower Paleozoic and Devonian carbonated rocks of Nepal which could be compared with the Belgian facies. This long distance comparison between the Belgian and the Nepalese basins will allow to have a better understanding of the phenomena that run the global carbonate sedimentation. The methods that will be used to achieve this work are: (1) bed by bed sampling; (2) petrographic analysis and facies modelling; (3) magnetic susceptibility analysis for correlations and eustatism and (4) paleontological datation. A first sedimentological campaign took place during the months of March and April 2009. It allowed to study three sections around Katmandu valley and two sections in the Annapurna range (Manang area). The sections studied around Katmandu (Pulchauki and Chandragiri Hill) belonged to the Formation of Chandragiri (Ordovician) and Godavari (Devonian) which are mainly constituted by carbonate rocks. The sections described in Manang area are mainly made-up by the terrigeneous rocks of the Dark Band, Tilicho Pass and Tilicho Lake Formation (Silurian to Lower Carboniferous). The diversity of facies observed in these five sections will be exposed. [less ▲]

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See detailLower Palaeozoic palaeo(bio)geographies
Wellman, C.H.; Steemans, Philippe ULg; Vecoli, M.

in Harper, D.A.T.; Servais, T. (Eds.) Early Palaeozoic biogeography and palaeogeography (2014)

Detailed reference viewed: 91 (6 ULg)
See detailThe Lower to Middle Devonian transitional flora from Dechra-Aït-Abdallah (Morocco).
Prestianni, Cyrille ULg; Meyer-Berthaud, Brigitte; Gerrienne, Philippe ULg

Conference (2010)

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See detailA Lower Tournaisian (Hastarian) silicified brachiopod-coral fauna from South Belgium
Denayer, Julien ULg; Mottequin, Bernard; Poty, Edouard

Conference (2015)

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See detailLower-Order Effects Adjustment in Quantitative Traits Model-Based Multifactor Dimensionality Reduction
Mahachie John, Jestinah ULg; Cattaert, Tom ULg; Van Lishout, François ULg et al

in PLoS ONE (2012)

Identifying gene-gene interactions or gene-environment interactions in studies of human complex diseases remains a big challenge in genetic epidemiology. An additional challenge, often forgotten, is to ... [more ▼]

Identifying gene-gene interactions or gene-environment interactions in studies of human complex diseases remains a big challenge in genetic epidemiology. An additional challenge, often forgotten, is to account for important lower-order genetic effects. These may hamper the identification of genuine epistasis. If lower-order genetic effects contribute to the genetic variance of a trait, identified statistical interactions may simply be due to a signal boost of these effects. In this study, we restrict attention to quantitative traits and bi-allelic SNPs as genetic markers. Moreover, our interaction study focuses on 2- way SNP-SNP interactions. Via simulations, we assess the performance of different corrective measures for lower-order genetic effects in Model-Based Multifactor Dimensionality Reduction epistasis detection, using additive and co-dominant coding schemes. Performance is evaluated in terms of power and familywise error rate. Our simulations indicate that empirical power estimates are reduced with correction of lower-order effects, likewise familywise error rates. Easy-to-use automatic SNP selection procedures, SNP selection based on ‘‘top’’ findings, or SNP selection based on p-value criterion for interesting main effects result in reduced power but also almost zero false positive rates. Always accounting for main effects in the SNP-SNP pair under investigation during Model-Based Multifactor Dimensionality Reduction analysis adequately controls false positive epistasis findings. This is particularly true when adopting a co-dominant corrective coding scheme. In conclusion, automatic search procedures to identify lower-order effects to correct for during epistasis screening should be avoided. The same is true for procedures that adjust for lower-order effects prior to Model-Based Multifactor Dimensionality Reduction and involve using residuals as the new trait. We advocate using ‘‘on-the-fly’’ lower-order effects adjusting when screening for SNP-SNP interactions using Model-Based Multifactor Dimensionality Reduction analysis. [less ▲]

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See detailThe lowest 5g-6h supermultiplet of Fe II
Biémont, Emile ULg; Johansson, S.; Palmeri, P.

in Physica Scripta (1997), 55

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See detailLowest negative parity baryons in the 1/Nc expansion
Matagne, Nicolas; Stancu, Floarea ULg

in Acta Physica Polonica. B, Proceedings Supplement (2010), 3

We review a recently proposed approach to study the lowest negative parity baryons within the $1/N_c$ expansion. The method is based on the derivation of the matrix elements of SU(2N$_f$) generators for ... [more ▼]

We review a recently proposed approach to study the lowest negative parity baryons within the $1/N_c$ expansion. The method is based on the derivation of the matrix elements of SU(2N$_f$) generators for mixed symmetric $[N_c-1,1]$ flavor-spin states. Presently it is applied to the N = 1 band and a comparison is made with a former method based on the decoupling of the system into a symmetric core of $N_c-1$ quarks and an excited one. We prove that the decoupling is not necessary and moreover, it misses some important physical consequences. [less ▲]

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See detailLa loyauté dans les procédures arbitrales
Kohl, Benoît ULg

in Liber Amicorum Guy Keutgen (2012)

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See detailLRPPRC mutations cause a phenotypically distinct form of Leigh syndrome with cytochrome c oxidase deficiency.
DEBRAY, François-Guillaume ULg; Morin, C.; Janvier, Annie et al

in Journal of Medical Genetics (2011)

Background The natural history of all known patients with French-Canadian Leigh disease (Saguenay-Lac-St-Jean cytochrome c oxidase deficiency, MIM220111, SLSJ-COX), the largest known cohort of patients ... [more ▼]

Background The natural history of all known patients with French-Canadian Leigh disease (Saguenay-Lac-St-Jean cytochrome c oxidase deficiency, MIM220111, SLSJ-COX), the largest known cohort of patients with a genetically homogeneous, nuclear encoded congenital lactic acidosis, was studied. Results 55 of 56 patients were homozygous for the A354V mutation in LRPPRC. One was a genetic compound (A354V/C1277Xdel8). Clinical features included developmental delay, failure to thrive, characteristic facial appearance and, in 90% of patients, acute crises that have not previously been detailed, either metabolic (fulminant lactic acidosis) and/or neurological (Leigh syndrome and/or stroke-like episodes). Survival ranged from 5 days to >30 years. 46/56 patients (82%) died, at a median age of 1.6 years. Of 73 crises, 38 (52%) were fatal. The immediate causes of death were multiple organ failure and/or Leigh disease. Major predictors of mortality during crises (p<0.005) were hyperglycaemia, hepatic cytolysis, and altered consciousness at admission. Compared to a group of SURF1-deficient Leigh syndrome patients assembled from the literature, SLSJ-COX is distinct by the occurrence of metabolic crises, leading to earlier and higher mortality (p=0.001). Conclusion SLSJ-COX is clinically distinct, with acute fatal acidotic crises on a backdrop of chronic moderate developmental delay and hyperlactataemia. Leigh syndrome is common. Stroke-like episodes can occur. The Leigh syndrome of SLSJ-COX differs from that of SURF1-related COX deficiency. SLSJ-COX has a different spectrum of associated abnormalities, acidotic crises being particularly suggestive of LRPPRC related Leigh syndrome. Even among A354V homozygotes, pronounced differences in survival and severity occur, showing that other genetic and/or environmental factors can influence outcome. [less ▲]

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See detailLSD1 cooperates with CTIP2 to promote HIV-1 transcriptional silencing.
Le Douce, Valentin; Colin, Laurence; Redel, Laetitia et al

in Nucleic Acids Research (2012), 40(5), 1904-15

Microglial cells are the main HIV-1 targets in the central nervous system (CNS) and constitute an important reservoir of latently infected cells. Establishment and persistence of these reservoirs rely on ... [more ▼]

Microglial cells are the main HIV-1 targets in the central nervous system (CNS) and constitute an important reservoir of latently infected cells. Establishment and persistence of these reservoirs rely on the chromatin structure of the integrated proviruses. We have previously demonstrated that the cellular cofactor CTIP2 forces heterochromatin formation and HIV-1 gene silencing by recruiting HDAC and HMT activities at the integrated viral promoter. In the present work, we report that the histone demethylase LSD1 represses HIV-1 transcription and viral expression in a synergistic manner with CTIP2. We show that recruitment of LSD1 at the HIV-1 proximal promoter is associated with both H3K4me3 and H3K9me3 epigenetic marks. Finally, our data suggest that LSD1-induced H3K4 trimethylation is linked to hSET1 recruitment at the integrated provirus. [less ▲]

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See detailLSP sneutrino decays
Aristizabal Sierra, Diego ULg; Restrepo, Diego; Spinner, Sogee

in Journal of High Energy Physics [=JHEP] (2013), 1305

In bilinear R-parity violation (BRpV), in which the superpotential includes a bilinear term between the lepton doublet and the up-type Higgs superfields, a sneutrino LSP can decay into pairs of heavy ... [more ▼]

In bilinear R-parity violation (BRpV), in which the superpotential includes a bilinear term between the lepton doublet and the up-type Higgs superfields, a sneutrino LSP can decay into pairs of heavy standard model states: W's, Z's, tops or Higgs bosons. These finals states can dominate over the traditionally considered bottom pair final state. This would lead to unique and novel supersymmetric signals with each supersymmetric event possibly producing two pairs of these heavy standard model fields. We investigate this possibility and find that the branching ratio into heavier states dominates when the bilinear term is much smaller than the sneutrino vacuum expectation value for a given sneutrino flavor. When BRpV is the only source of neutrino masses these decays can only dominate for one of the sneutrino generations. Relaxing this constraint opens these channels for all three generations. [less ▲]

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See detail@LTER et la Pl@teforme FLE de l’ULg, Compte-rendu d’expériences et d’expérimentations
Thonard, Audrey ULg; Gueury, Véronique ULg

in Langage et l'Homme (Le) : Recherches Pluridisciplinaires sur le Langage (2012), 47(1),

L’enseignement des langues en ligne a fait son apparition il y a quelques années à l’Université de Liège. Celle-ci a opté, dans un premier temps, pour un logiciel commercialisé puis a investi dans la ... [more ▼]

L’enseignement des langues en ligne a fait son apparition il y a quelques années à l’Université de Liège. Celle-ci a opté, dans un premier temps, pour un logiciel commercialisé puis a investi dans la création de cours complets en ligne, conçus par une équipe d’enseignants de l’Institut Supérieur des Langues Vivantes et baptisés @LTER. Fort de cette expérience, cet Institut a souhaité partager ses compétences avec les futurs professeurs de français langue étrangère dans le cadre de leur cursus universitaire. Cet article se propose d’aborder ces diverses expériences avec les TICe et ces nouvelles pratiques pédagogiques et didactiques adoptées par l’ULg pour l’apprentissage et l’enseignement du français langue étrangère. La première partie de l’article traite du dispositif mis en place à l’attention des étudiants Erasmus « in » ; la seconde rapportera les réflexions, les observations et les expérimentations qui ont entraîné des révisions régulières du programme du cours intitulé « Les TICe pour l’apprentissage/enseignement du FLE », inscrit au programme du Master en Didactique du FLE à l’Université de Liège, et qui ont finalement donné le jour à la Pl@teforme FLE de l’ULg. [less ▲]

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See detailLe LTP : Un jeu pour le diagnostic, l'intervention et la recherche
Miscioscia, Marina ULg; Lejeune, Génévieve

Conference (2014, May 16)

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See detailLubrication by charged polymers
Raviv, Uri; Giasson, Suzanne; Kampf, Nir et al

in Nature (2003), 425(6954), 163-165

Long-ranged forces between surfaces in a liquid control effects from colloid stability [1] to biolubrication [2], and can be modified either by steric factors due to flexible polymers [3], or by surface ... [more ▼]

Long-ranged forces between surfaces in a liquid control effects from colloid stability [1] to biolubrication [2], and can be modified either by steric factors due to flexible polymers [3], or by surface charge effects [4]. In particular, neutral polymer 'brushes' may lead to a massive reduction in sliding friction between the surfaces to which they are attached [5-7], whereas hydrated ions can act as extremely efficient lubricants between sliding charged surfaces [8]. Here we show that brushes of charged polymers (polyelectrolytes) attached to surfaces rubbing across an aqueous medium result in superior lubrication compared to other polymeric surfactants. Effective friction coefficients with polyelectrolyte brushes in water are lower than about 0.0006-0.001 even at low sliding velocities and at pressures of up to several atmospheres (typical of those in living systems). We attribute this to the exceptional resistance to mutual interpenetration displayed by the compressed, counterion-swollen brushes, together with the fluidity of the hydration layers surrounding the charged, rubbing polymer segments. Our findings may have implications for biolubrication effects, which are important in the design of lubricated surfaces in artificial implants, and in understanding frictional processes in biological systems. [less ▲]

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