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See detailSéminaire de recherches ULaval Québec
Contor, Justine ULg

Scientific conference (2017)

Il s'agit d'une présentation réalisée dans le cadre d'un séminaire de recherche à l'Université Laval

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See detailDiálogo entre un poeta medieval y una obra aurisecular: Antón de Montoro a partir de La Lozana andaluza de Francisco Delicado
Francois, Jeromine ULg

in González, Aurelio (Ed.) Perspectivas y proyecciones de la literatura medieval (2017)

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See detailLa Célestine versus Lazarillo: un cas de crossover littéraire
Francois, Jeromine ULg

Conference (2017)

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See detailVariability of D and H in the Martian Upper Atmosphere Observed with the MAVEN IUVS Echelle Channel
Clarke, J. T.; Mayyasi, M.; Bhattacharyya, D. et al

in Journal of Geophysical Research. Space Physics (2017)

The MAVEN IUVS instrument contains an echelle spectrograph channel designed to measure D and H Ly α emissions from the upper atmosphere of Mars. This channel has successfully recorded both emissions ... [more ▼]

The MAVEN IUVS instrument contains an echelle spectrograph channel designed to measure D and H Ly α emissions from the upper atmosphere of Mars. This channel has successfully recorded both emissions, which are produced by resonant scattering of solar emission, over the course of most of a martian year. The fundamental purpose of these measurements is to understand the physical principles underlying the escape of H and D from the upper atmosphere into space, and thereby to relate present-day measurements of an enhanced HDO/H2O ratio in the bulk atmosphere to the water escape history of Mars. Variations in these emissions independent of the solar flux reflect changes in the density and/or temperature of the species in the upper atmosphere. The MAVEN measurements show that the densities of both H and D vary by an order of magnitude over a martian year, and not always in synch with each other. This discovery has relevance to the processes by which H and D escape into space. One needs to understand the controlling factors to be able to extrapolate back in time to determine the water escape history from Mars at times when the atmosphere was thicker, when the solar flux and solar wind were stronger, etc. Further measurements will be able to identify the specific controlling factors for the large changes in H and D, which likely result in large changes in the escape fluxes of both species. [less ▲]

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See detailNitric Oxide Nightglow and Martian Mesospheric Circulation from MAVEN/IUVS Observations and LMD-MGCM Predictions
Stiepen, Arnaud ULg; Jain; Schneider et al

in Journal of Geophysical Research. Space Physics (2017)

We report results from a study of nitric oxide nightglow over the north- ern hemisphere of Mars during winter, the southern hemisphere during fall equinox and equatorial latitudes during summer in the ... [more ▼]

We report results from a study of nitric oxide nightglow over the north- ern hemisphere of Mars during winter, the southern hemisphere during fall equinox and equatorial latitudes during summer in the northern hemisphere based on observations of the delta and gamma bands between 190 and 270 nm by the Imaging UltraViolet Spectrograph (IUVS) on the MAVEN spacecraft. The emission reveals recombination of N and O atoms dissociated on the day- side of Mars and transported to the nightside. We characterize the bright- ness (from 0.2 to 30 kR) and altitude (from 40 to 115 km) of the NO night- glow layer, as well as its topside scale height (mean of 11 km). We show the possible impact of atmospheric waves forcing longitudinal variability, asso- ciated with an increased brightness by a factor 3 in the 140 - 200 longitude region in the northern hemisphere winter and in the -102 to -48 longitude region at summer. Such impact to the NO nightglow at Mars was not seen before. Quantitative comparison with calculations of the LMD-MGCM (Lab- oratoire de M et eorologie Dynamique - Global Circulation Model) suggests that the model globally reproduces the trends of the NO nightglow emission and its seasonal variation, but also indicates large discrepancies (up to a fac- tor 50 fainter in the model) in northern winter at low to mid-latitudes. This suggests that the predicted transport is too e cient towards the night win- ter pole in the thermosphere by 20 latitude north. [less ▲]

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See detailEffect of undisturbed ground temperature on the design of closed-loop geothermal systems: A case study in a semi-urban environment
Radioti, Georgia ULg; Sartor, Kevin ULg; Charlier, Robert ULg et al

in Applied Energy (2017)

This paper presents temperature measurements in four Borehole Heat Exchangers (BHEs), equipped with fiber optics and located in a semi-urban environment (campus of the University of Liege, Belgium). A 3D ... [more ▼]

This paper presents temperature measurements in four Borehole Heat Exchangers (BHEs), equipped with fiber optics and located in a semi-urban environment (campus of the University of Liege, Belgium). A 3D numerical model is also presented to simulate the heat loss from the surrounding structures into the subsurface. The mean undisturbed ground temperature was estimated from data during the preliminary phase of a thermal response test (water circulation in the pipe loops), as well as from borehole logging measurements. The measurements during water circulation can significantly overestimate the ground temperature (up to 1.7 C in this case study) for high ambient air temperature during the test, resulting in an overestimation of the maximum extracted power and of the heat pump coefficient of performance (COP). To limit the error in the COP and the extracted power to less than 5%, the error in the undisturbed temperature estimation should not exceed ±1.5 °C and ±0.6 °C respectively. In urbanised areas, configurations of short BHEs (length < 40 m) could be economically advantageous (decreased installation and operation costs) compared to long BHEs, especially for temperature gradient lower than 0.05 °C/m. [less ▲]

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See detailThe frequency and influence of dementia risk factors in prodromal Alzheimer’s disease
Bos, Isabelle; Vos, Stephanie J.; Frölich, Lutz et al

in Neurobiology of Aging (2017), 56

We investigated whether dementia risk factors were associated with prodromal Alzheimer’s disease (AD) according to the International Working Group-2 and National Institute of Aging-Alzheimer’s Association ... [more ▼]

We investigated whether dementia risk factors were associated with prodromal Alzheimer’s disease (AD) according to the International Working Group-2 and National Institute of Aging-Alzheimer’s Association criteria, and with cognitive decline. 1394 subjects from with Mild Cognitive Impairment (MCI) from 14 different studies were classified according to these research criteria, based on cognitive performance and biomarkers. We compared the frequency of ten risk factors between the subgroups and used Cox-regression to examine the effect of risk factors on cognitive decline. Depression, obesity and hypercholesterolemia occurred more often in individuals with low-AD-likelihood, compared to those with a high-AD-likelihood. Only alcohol use increased the risk of cognitive decline, regardless of AD pathology. These results suggest that traditional risk factors for AD are not associated with prodromal AD or with progression to dementia, among subjects with MCI. Future studies should validate these findings and determine whether risk factors might be of influence at an earlier stage (i.e. preclinical) of AD. [less ▲]

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See detailCounting the number of non-zero coefficients in rows of generalized Pascal triangles
Leroy, Julien ULg; Rigo, Michel ULg; Stipulanti, Manon ULg

in Discrete Mathematics (2017), 340

This paper is about counting the number of distinct (scattered) subwords occurring in a given word. More precisely, we consider the generalization of the Pascal triangle to binomial coefficients of words ... [more ▼]

This paper is about counting the number of distinct (scattered) subwords occurring in a given word. More precisely, we consider the generalization of the Pascal triangle to binomial coefficients of words and the sequence (S(n))n≥0 counting the number of positive entries on each row. By introducing a convenient tree structure, we provide a recurrence relation for (S(n))n≥0. This leads to a connection with the 2-regular Stern–Brocot sequence and the sequence of denominators occurring in the Farey tree. Then we extend our construction to the Zeckendorf numeration system based on the Fibonacci sequence. Again our tree structure permits us to obtain recurrence relations for and the F-regularity of the corresponding sequence. [less ▲]

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See detailThe use of mesenchymal stromal cells in solid organ transplantation
GREGOIRE, Céline ULg; DETRY, Olivier ULg; Jouret, François ULg et al

in The Biology and Therapeutic Application of Mesenchymal Cells (2017)

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See detailCRISPR-Cas9-mediated efficient directed mutagenesis and RAD51-dependent and RAD51-independent gene targeting in the moss Physcomitrella patens
Collonnier, Cécile; Epert, Aline; Mara, Kostlend et al

in Plant Biotechnology Journal (2017), 15

The ability to address the CRISPR-Cas9 nuclease complex to any target DNA using customizable single-guide RNAs has now permitted genome engineering in many species. Here, we report its first successful ... [more ▼]

The ability to address the CRISPR-Cas9 nuclease complex to any target DNA using customizable single-guide RNAs has now permitted genome engineering in many species. Here, we report its first successful use in a nonvascular plant, the moss Physcomitrella patens. Single-guide RNAs (sgRNAs) were designed to target an endogenous reporter gene, PpAPT, whose inactivation confers resistance to 2-fluoroadenine. Transformation of moss protoplasts with these sgRNAs and the Cas9 coding sequence from Streptococcus pyogenes triggered mutagenesis at the PpAPT target in about 2% of the regenerated plants. Mainly, deletions were observed, most of them resulting from alternative end-joining (alt-EJ)-driven repair. We further demonstrate that, in the presence of a donor DNA sharing sequence homology with the PpAPT gene, most transgene integration events occur by homology-driven repair (HDR) at the target locus but also that Cas9- induced double-strand breaks are repaired with almost equal frequencies by mutagenic illegitimate recombination. Finally, we establish that a significant fraction of HDR-mediated gene targeting events (30%) is still possible in the absence of PpRAD51 protein, indicating that CRISPR-induced HDR is only partially mediated by the classical homologous recombination pathway. [less ▲]

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See detailCaryl Phillips’s The Lost Child: A Story of Loss and Connection
Ledent, Bénédicte ULg; O'Callaghan, Evelyn

in Ariel : A Review of International English Literature (2017)

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See detailIsotopic niches of Fin Whales from the Mediterranean Sea and the Celtic sea (North Atlantic)
Das, Krishna ULg; Holleville, Ophélie; Ryan, Conor et al

in Marine Environmental Research (2017), 127

The fin whale (Balaenoptera physalus) is the most abundant and widespread mysticete species in the Mediterranean Sea, found mostly over deep, offshore waters of the western and central portion of the ... [more ▼]

The fin whale (Balaenoptera physalus) is the most abundant and widespread mysticete species in the Mediterranean Sea, found mostly over deep, offshore waters of the western and central portion of the region. In the Mediterranean, this species is known to feed mainly on krill, in contrast to its Atlantic counterpart, which displays a more diversified diet. The International Whaling Commission recognizes several managements units in the Atlantic and the Mediterranean Sea and the connectivity between these populations is still being debated. Questions remain about inter-individual feeding strategies and trophic ecology. The goal of this study was to compare isotopic niches of fin whales from the Mediterranean Sea and the Celtic Sea (North Atlantic). δ13C and δ15N values were analysed in 136 skin biopsies from free-ranging Mediterranean fin whales sampled in 2010 and 2011 during campaigns at sea. δ13C and δ15N values ranged from -20.4 to -17.1 ‰ and from 5.9 to 8.9 ‰, respectively. These values are in good agreement with those estimated previously from baleen plates from Mediterranean and North Atlantic fin whales. The narrow isotopic niche width of the Mediterranean fin whale (Standard Ellipses area SEAc) compared to the North Atlantic fin whale raises many concerns in the context of global changes and long-term consequences. One could indeed expect that species displaying narrow niches would be more susceptible to ecosystem fragmentation and other anthropogenic impacts. [less ▲]

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See detailInfluence of sawdust addition on drying of wastewater sludges: Comparison of structural characteristics
Li, Jie; Plougonven, Erwan ULg; Fraikin, Laurent ULg et al

in Drying Technology (2017), 35(8), 925-932

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See detailSingle and dual cyclodextrins systems for the enantiomeric and diastereoisomeric separations of structurally related dihydropyridone analogues.
Delplanques, Thibaut; Boulahjar, Rajaa; Charton, Julie et al

in Electrophoresis (2017)

Cyclodextrin capillary electrophoresis methods (CD-CZE) were developed for complete enantiomeric and diastereoisomeric separations of a series of ten dihydropyridone analogues, of which eight were neutral ... [more ▼]

Cyclodextrin capillary electrophoresis methods (CD-CZE) were developed for complete enantiomeric and diastereoisomeric separations of a series of ten dihydropyridone analogues, of which eight were neutral, one was anionic and one was cationic. Ten different systems comprising one or two cyclodextrins were found to successfully separate the isomers thanks to a screening approach. Among the tested cyclodextrins, HS-gamma-CD, either in a single or in a dual system, in a phosphate buffer using capillaries dynamically coated with polyethylene oxide (PEO), and SBE-beta-CD, either in a single or in a dual system, in a borate buffer using uncoated capillaries, were the most selective selectors. The effects of different parameters such as the nature and concentration of the cyclodextrins, nature and concentration of the buffer, and voltage were examined. The precision and limits of detection and quantification were evaluated for the optimized methods. This article is protected by copyright. All rights reserved. [less ▲]

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See detailCapillary electrophoresis in the context of drug discovery.
Farcas, Elena ULg; Pochet, Lionel; Crommen, Jacques ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2017)

Capillary Electrophoresis is a very efficient and resolutive separation technique used for many years in the analytical field. Despite all its assets, CE remains poorly used in drug discovery. This can be ... [more ▼]

Capillary Electrophoresis is a very efficient and resolutive separation technique used for many years in the analytical field. Despite all its assets, CE remains poorly used in drug discovery. This can be explained by the relatively low number of experienced CE practitioners, the maturity of HPLC in the pharmaceutical industry and some intrinsic limitations of the technique. The objective of this review is to focus our attention on recent developments of this technique in three different drug discovery areas: bioassays, drug-plasma interactions and drug metabolism studies. These developments were based on two important abilities of CE: the capacity to measure non-covalent interactions in solution and the ability to use a portion of the capillary as a reactor while the rest of the capillary is used for the separation of the product of the reaction. [less ▲]

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See detailIdentification of walnut husk (Juglans regia L.) volatiles and the behavioural response of the invasiveWalnut Husk Fly, Rhagoletis completa Cresson
Sarles, Landry ULg; Boullis, Antoine ULg; Fassotte, Bérénice ULg et al

in Pest Management Science (2017)

Abstract BACKGROUND: Several European countries are important walnut (Juglans regia L.) producers. However, these countries must contendwith the recent introduction of theWalnut Husk Fly,Rhagoletis ... [more ▼]

Abstract BACKGROUND: Several European countries are important walnut (Juglans regia L.) producers. However, these countries must contendwith the recent introduction of theWalnut Husk Fly,Rhagoletis completa Cresson (Diptera, Tephritidae),which is causing severe economic losses, especially in organic production. Because most Tephritid fruit flies use kairomones in their search for host plants, we hypothesise that this highly specialist species orients toward the volatile blend released by walnut husks. RESULTS:We collected, identified, and quantified the volatile organic chemicals (VOCs) released by walnut husks from themost commonly cultivated variety in France (Franquette). Then, the behavioural response of R. completa toward synthetic odour blends was recorded in dual choice assays conducted in net cages. A total of 26 VOCs were identified, with 𝜶-pinene, 𝜷-pinene, trans-linalool, eugenol, and tetradecane representing the major constituents. In the dual choice assay, male and female R. completa were strongly attracted to synthetic blend that includedmost of the identified husk VOCs. CONCLUSION:When searching for a host plant, R. completa use host fruit kairomones. The potential of these semiochemicals in monitoring andmanagement of this quarantine pest is discussed. [less ▲]

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See detailLes écoles liégeoises de physiologie et de médecine aux 19e et 20e siècle
Geenen, Vincent ULg

Conference given outside the academic context (2017)

La physiologie constitue une véritable révolution à l’époque de Claude Bernard (1813-1878) qui l’institue alors comme le véritable socle de la médecine expérimentale moderne. Avec Charles Darwin, il est ... [more ▼]

La physiologie constitue une véritable révolution à l’époque de Claude Bernard (1813-1878) qui l’institue alors comme le véritable socle de la médecine expérimentale moderne. Avec Charles Darwin, il est un des géants de la science du XIXe siècle et ces deux grands auteurs vont exercer une profonde influence sur de nombreux disciples à l’Université de Liège. Dans le même temps, Liège héberge aussi l’Allemand Théodore Schwann, auteur de la théorie cellulaire selon laquelle la cellule est l’unité de base des mondes animal et végétal. Grâce aux travaux de Edouard Van Beneden, Léon Fredericq et Marcel Florkin, l’Université de Liège acquiert une réputation mondiale. Il est important de rappeler que de véritables révolutions scientifiques ont eu lieu dans le passé, alors que la révolution génétique se déroule sous nos yeux. Les changements que cette dernière produit sont si profonds et si prometteurs que nous pourrions être tentés de négliger notre héritage en le considérant comme dépassé ou inintéressant. Le rappel de l’œuvre gigantesque des physiologistes de l’Université de Liège démontre néanmoins l’inconscience d’un tel oubli. La physiologie contemporaine a de plus en plus déserté les domaines de l’intégration pour se concentrer vers des démarches de plus en plus réductionnistes. Nous pensons toutefois que les voies de l’intégration ne sont pas complètement interdites et qu’il existe encore de nombreux chemins à explorer, ne serait-ce que celui par lequel les systèmes nerveux et endocrine interviennent dans le contrôle de nos défenses immunitaires vis-à-vis des agressions extérieures et, inversement, comment le système immunitaire est capable d’influencer les systèmes nerveux et endocrine. [less ▲]

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