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See detailRachid Tahzima lauréat du journal of general virology for best oral scientific presentation award 2017
Massart, Sébastien ULiege; Tahzima, Rachid

Article for general public (2017)

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See detailConsequences of genetic selection for environmental impact traits on economically important traits in dairy cows
Kandel, Purna ULiege; Vanderick, Sylvie ULiege; Vanrobays, Marie-Laure ULiege et al

in Animal Production Science (2017)

Methane (CH4) emission is an important environmental trait in dairy cows. Breeding aiming to mitigate CH4 emissions require the estimation of genetic correlations with other economically important traits ... [more ▼]

Methane (CH4) emission is an important environmental trait in dairy cows. Breeding aiming to mitigate CH4 emissions require the estimation of genetic correlations with other economically important traits and the prediction of their selection response. In this study, test-day CH4 emissions were predicted from milk mid-infrared spectra of Holstein cows. Predicted CH4 emissions (PME) and log-transformed CH4 intensity (LMI) computed as the natural logarithm of PME divided by milk yield (MY). Genetic correlations of PME and LMI with traits used currently were approximated from correlations between estimated breeding values of sires. Values were for PME with MY 0.06, fat yield (FY) 0.09, protein yield (PY) 0.13, fertility 0.17; body condition score (BCS) –0.02; udder health (UDH) 0.22; and longevity 0.22. As expected by its definition, values were negative for LMI with production traits (MY –0.61; FY –0.15 and PY –0.40) and positive with fertility (0.36); BCS (0.20); UDH (0.08) and longevity (0.06). The genetic correlations of 33 type traits with PME ranged from –0.12 to 0.25 and for LMI ranged from –0.22 to 0.18. Without selecting PME and LMI (status quo) the relative genetic change through correlated responses of other traits were in PME by 2% and in LMI by –15%, but only due to the correlated response to MY. Results showed for PME that direct selection of this environmental trait would reduce milk carbon foot print but would also affect negatively fertility. Therefore, more profound changes in current indexes will be required than simply adding environmental traits as these traits also affect the expected progress of other traits. [less ▲]

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See detailRelease of Neutrophils Extracellular Traps as a main trigger for asthma onset
Radermecker, Coraline ULiege; Sabatel, Catherine ULiege; Toussaint, Marie et al

Poster (2017, June 20)

Allergic asthma is an important Th2 associated immunopathology. Even if the pathology of the disease is well described, its etiology is still largely unknown. Nevertheless, some environmental factors like ... [more ▼]

Allergic asthma is an important Th2 associated immunopathology. Even if the pathology of the disease is well described, its etiology is still largely unknown. Nevertheless, some environmental factors like viral infections and exposition to low doses of lipopolysaccharide (LPS) strongly increase the risk of disease inception. Interestingly, these two particular risk factors both induce a strong recruitment of neutrophils into the lung. Recently, scientists highlighted the ability of neutrophils to form neutrophils extracellular traps (NETs) composed of a network of extracellular DNA associated to anti-microbial peptides. NETs release (or NETosis) is an important component in organism defence against pathogen invasion but has also been identified as initiator of pathophysiological conditions like erythematous systemic lupus, gout and diabetes. In this study, we investigated the role of NETs as potential asthma inducers in specific pro-Th2 environmental risk factors like respiratory viral infections and low LPS doses exposures (also known as hygiene hypothesis). First, we assessed the correlation between respiratory viral infection or low LPS exposure and NETosis using western blot and confocal microscopy analysis. An influenza A infection induced a strong NETs release between day three and seven after viral inoculation whereas exposition to low (100 ng LPS) but not to high (10 µg LPS) LPS doses also promoted NETosis within 24 hours following the exposition. Then we developed two mouse models, a virus-induced asthma model and a model of asthma promoted by exposition to low LPS doses. In these models, only previously infected mice or mice exposed to low LPS doses displayed all the characteristics of allergic asthma following sensitization and challenge to house dust mite (HDM). The role of NETs in asthma onset was then demonstrated using three NETosis inhibitors (DNAse, Cl-amidine and inhibitor of neutrophil elastase) in our models as infected or low LPS doses exposed mice exhibited strong decreased of all key asthma features when treated with NETs inhibitors compared to non-treated mice. Finally, to address how NETs could lead to a TH2 immune response, we analysed by flow cytometry the distinct subpopulations of lung dendritic cells (DCs) in our two mice models. We observed, during the NETs release phase, a recruitment of monocytic derived DCs (moDCs). In conclusion, we have demonstrated an unexpected role for NETs in asthma onset by recruiting lung moDCs. [less ▲]

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See detailOptimization of an electrophoretic approach for the screening and the development of new antithrombotic drugs
Farcas, Elena ULiege; Bouckaert, Charlotte; Servais, Anne-Catherine ULiege et al

Conference (2017, June 20)

The discovery of lead compounds that can modulate the activity of a biological target is essential to provide efficient pharmacological tools and to serve as starting points for new drug generations ... [more ▼]

The discovery of lead compounds that can modulate the activity of a biological target is essential to provide efficient pharmacological tools and to serve as starting points for new drug generations. Fragment-based drug discovery (FBDD) approach is an attractive tool for the identification of new selective inhibitors of a target of interest, but its success largely depends on the ability to develop screening bioassays capable to detect and gauge weak affinity binders. To achieve this goal, we investigated capillary electrophoresis (CE) for identifying and ranking fragments from an initial library. Indeed, due to its ability to evaluate weak interactions, CE seems to be promising for fragment-based screening. This technique is a powerful analytical tool with a unique separation mechanism, speed, efficiency and versatility. Its main advantages are low protein consumption, higher throughput compared to NMR and X-ray crystallography and the fact that screening can be carried out using native protein in physiological solution without the need of immobilization. We developed a proof of concept study on thrombin, a serine protease implicated in the coagulation cascade using affinity capillary electrophoresis (ACE) for ranking fragments from an initial library. For this study, we followed a probe ligand, benzamidine, and we investigated interactions with the target by monitoring the changes of its electrophoretic mobility upon binding. The first step of this study consisted in the optimization of the experimental conditions suitable for the CE method (target and probe ligand concentrations, separation buffer composition, voltage, separation effective length, target partial filling…). Then, numerous thrombin inhibitors with a wide range of inhibitory potency (i.e. Ki 200 µM – 5 nM) were tested to validate our system demonstrating the possibility to fish binders in the optimized conditions. We also checked the absence of non-specific binding with the target using the inactivated enzyme at the binding site. It is noteworthy that in this operating system (ACE assay), binding occurs in free solution using physiological buffers, thus preventing artifacts that may result from target immobilization, which is a requirement for some techniques such as SPR. [less ▲]

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See detailChromatographic analysis of alkaloids in Aconitum pollen : towards new insights in plant protection mechanisms
Vanderplanck, Maryse ULiege; Glauser, Gaëtan; Tyteca, Eva ULiege et al

Conference (2017, June 19)

Alkaloids are a class of naturally occurring organic nitrogen-containing bases that are found primarily in plants. They display a huge diversity with more than 3,000 different types already identified ... [more ▼]

Alkaloids are a class of naturally occurring organic nitrogen-containing bases that are found primarily in plants. They display a huge diversity with more than 3,000 different types already identified. Next to their different pharmacological and therapeutic effects, alkaloids can have a deleterious impact on organisms as they are known to be neurotoxic and cardiotoxic for mammals and insects. In the current context of worldwide bee decline, occurrence of such compounds in floral production, i.e. nectar and pollen, raises major concerns. They could be beneficial to bees by protecting them against disease and pathogens but they could also cause toxicity. Until now alkaloids, and their effect on human health, are mainly studied in vegetative parts of plants. More recently the natural occurrence of alkaloids in nectar was also studied to investigate their effect on bee health. Whereas nectar chemicals can relatively easily and quickly be analyzed by chromatography, extracting chemicals from low pollen amount remains a challenge because of pollen structure and complexity. However, characterization of pollen chemicals can lead to valuable insight in their impact on pollinators allowing the development of mitigation strategies. In this study, we used a UHPLC-(ESI)-Q-ToF/MS method allowing the identification and quantification of alkaloids in pollen matrices from four Aconitum species; A. lycoctonum, A. napellus compactum, A. napellus neomontanum and A. variegatum. Alkaloid extraction was performed using bead-beating disruption of the pollen sample and chromatographic analysis was carried out on an Acquity UPLC system interfaced with a Synapt G2 QTOF. The separation was achieved in gradient mode on an Acquity UPLC BEH C18 column and detection was performed in electrospray positive ionization mode (ES+). Alkaloid concentrations were measured as aconitine equivalents by using a pure aconitine standard as reference compound. The total amount of alkaloids in Aconitum pollen ranged from 0.75 to 1.20 mg/g with 859 different compounds detected, some of them being pollen-specific. Statistical analyses were conducted on the global dataset to assess both quantitative and qualitative interspecific differences. One-way analysis of variance was performed on the total alkaloid content while a permutational test of multivatiate analysis of variance was used to compare the alkaloid profiles among the four Aconitum species. Results are briefly discussed in an ecological context. [less ▲]

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See detailDEVELOPMENT OF A MULTISCALE CONVECTIVE LABSCALE DRYER
Fraikin, Laurent ULiege; Salmon, Thierry ULiege; Léonard, Angélique ULiege

Poster (2017, June 19)

The convective drying technology is currently used in many industries but the industrial process is frequently poorly mastered and some design security factors are used. The lack of optimized conception ... [more ▼]

The convective drying technology is currently used in many industries but the industrial process is frequently poorly mastered and some design security factors are used. The lack of optimized conception rules lead to large energy consumptions. In the same perspective, the use of superheated steam as drying fluid expands and requests the improvement of the knowledge about this specific drying process. For this goal, the PEP’s developed a new convective labscale dryer to conduct various studies. This article presents the new dryer called VESAC. [less ▲]

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See detailSTUDY ON THE STRUCTURAL EVOLUTION OF SEWAGE SLUDGE DURING CONVECTIVE DRYING
Li, Jie; Fraikin, Laurent ULiege; Salmon, Thierry ULiege et al

Poster (2017, June 19)

The structure of the sludge sample continues changing during drying as a result of the shrinkage phenomenon. Then the exchange area becomes smaller and the drying rate decreases. The sludge collected in a ... [more ▼]

The structure of the sludge sample continues changing during drying as a result of the shrinkage phenomenon. Then the exchange area becomes smaller and the drying rate decreases. The sludge collected in a wastewater treatment plant (Grosses Battes WWTP, Belgium) was chosen for both lab-scale experiment and pilot-scale experiment. X-ray macrotomography (resolution: 0.36 mm per pixel) and X-ray microtomography (resolution: 41 μm per pixel) were used to explore the structure evolution of the sludge bed and the single extrudate respectively. 2D cross-sections of the sludge bed and the single extrudate were acquired, which supply a convenient way to investigate the evolution of the structure. The results show that the structure of both the sludge bed and the single extrudate distinctly changes during the drying process. [less ▲]

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See detailMODELING MOISTURE TRANSFER OF MORTAR SUBMITED TO CONVECTIVE DRYING
Kahlerras, Loubna ULiege

Poster (2017, June 19)

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See detailGeneralized Pascal triangles for binomial coefficients of finite words
Stipulanti, Manon ULiege

Conference (2017, June 19)

We introduce a generalization of Pascal triangle based on binomial coefficients of finite words. These coefficients count the number of times a finite word appears as a subsequence of another finite word ... [more ▼]

We introduce a generalization of Pascal triangle based on binomial coefficients of finite words. These coefficients count the number of times a finite word appears as a subsequence of another finite word. Similarly to the Sierpiński gasket that can be built as the limit set, for the Hausdorff distance, of a convergent sequence of normalized compact blocks extracted from Pascal triangle modulo 2, we describe and study the first properties of the subset of [0, 1] × [0, 1] associated with this extended Pascal triangle modulo a prime p. Then we create a new sequence from this extended Pascal triangle that counts, on each row of this triangle, the number of positive binomial coefficients. We show that this sequence is 2-regular. To extend our work, we construct a Pascal triangle using the Fibonacci representations of all the nonnegative integers and we define the corresponding sequence of which we study the regularity. This regularity is an extension of the classical k-regularity of sequences. [less ▲]

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See detailConvective drying : experimental campaign and numerical modelling
Hubert, Julien ULiege; Plougonven, Erwan ULiege; Léonard, Angélique ULiege et al

Conference (2017, June 19)

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See detailOptimiaztion of an electrophoretic approach for the screening and the development of new antithrombotic drugs
Farcas, Elena ULiege; Bouckaert, Charlotte; Servais, Anne-Catherine ULiege et al

Poster (2017, June 19)

The discovery of lead compounds that can modulate the activity of a biological target is essential to provide efficient pharmacological tools and to serve as starting points for new drug generations ... [more ▼]

The discovery of lead compounds that can modulate the activity of a biological target is essential to provide efficient pharmacological tools and to serve as starting points for new drug generations. Fragment-based drug discovery (FBDD) approach is an attractive tool for the identification of new selective inhibitors of a target of interest, but its success largely depends on the ability to develop screening bioassays capable to detect and gauge weak affinity binders. To achieve this goal, we investigated capillary electrophoresis (CE) for identifying and ranking fragments from an initial library. Indeed, due to its ability to evaluate weak interactions, CE seems to be promising for fragment-based screening. This technique is a powerful analytical tool with a unique separation mechanism, speed, efficiency and versatility. Its main advantages are low protein consumption, higher throughput compared to NMR and X-ray crystallography and the fact that screening can be carried out using native protein in physiological solution without the need of immobilization. We developed a proof of concept study on thrombin, a serine protease implicated in the coagulation cascade using affinity capillary electrophoresis (ACE) for ranking fragments from an initial library. For this study, we followed a probe ligand, benzamidine, and we investigated interactions with the target by monitoring the changes of its electrophoretic mobility upon binding. The first step of this study consisted in the optimization of the experimental conditions suitable for the CE method (target and probe ligand concentrations, separation buffer composition, voltage, separation effective length, target partial filling…). Then, numerous thrombin inhibitors with a wide range of inhibitory potency (i.e. Ki 200 µM – 5 nM) were tested to validate our system demonstrating the possibility to fish binders in the optimized conditions. We also checked the absence of non-specific binding with the target using the inactivated enzyme at the binding site. It is noteworthy that in this operating system (ACE assay), binding occurs in free solution using physiological buffers, thus preventing artifacts that may result from target immobilization, which is a requirement for some techniques such as SPR. [less ▲]

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See detailDesign and experimental validation of an adaptive control law to maximize power generation of a small-scale waste heat recovery system
Hernandez Naranjo, Jairo Andrés ULiege; Desideri, Adriano ULiege; Gusev, Sergei et al

in Applied Energy (2017), 203

Increasing the energy efficiency of industrial processes is a challenge that involves, not only improving the methodologies for design and manufacturing, but optimizing performance during part-load ... [more ▼]

Increasing the energy efficiency of industrial processes is a challenge that involves, not only improving the methodologies for design and manufacturing, but optimizing performance during part-load operation and transient conditions. A well-adopted solution consists of developing waste heat recovery (WHR) systems based on Organic Rankine Cycle (ORC) power units. The highest efficiency for such cycle is obtained at low superheating values, corresponding to the situation where the system exhibits time-varying nonlinear dynamics, triggered by the fluctuating nature of the waste heat source. In this paper, an adaptive control law using the Model Predictive Control (MPC) framework is proposed. This work goes a step beyond most of the existing scientific works in the field of ORC power systems, since the MPC controller is implemented in a lab-scale prototype, and its performance compared against a gain-scheduled PID strategy. The experimental results show that the adaptive MPC outperforms the gain-scheduled PID based strategy, as it allows to accurately regulate the evaporating temperature, while keeping vapor condition at the inlet of the expander i.e., the superheating, in a safe operating range, thus increasing the net power generation. [less ▲]

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See detailDEVELOPMENT AND VALIDATION OF A FAST SFC METHOD FOR THE ANALYSIS OF FLAVONOIDS IN PLANT EXTRACTS
Huang, Yang ULiege; Jiang, Zhengjin; Fillet, Marianne ULiege et al

Poster (2017, June 18)

Flavonoids from plants always show a wide range of biological activities [1-2]. In the present study, a rapid and highly efficient supercritical fluid chromatography (SFC) method was developed for the ... [more ▼]

Flavonoids from plants always show a wide range of biological activities [1-2]. In the present study, a rapid and highly efficient supercritical fluid chromatography (SFC) method was developed for the separation of 12 flavonoids. After careful optimization, the 12 flavonoids were baseline separated on a ZORBAX RX-SIL column using gradient elution. A 0.1% phosphoric acid solution in methanol was found to be the most suitable polar mobile phase component for the separation of flavonoids. From the viewpoint of retention and resolution, a backpressure of 200 bar and a temperature of 40 °C were shown to give the best results. Compared with a previously developed reverse phase liquid chromatography method, the SFC method could provide flavonoid separations that were about three times faster, while maintaining good peak shape and comparable peak efficiency. This SFC method was validated and applied to the analysis of five flavonoids (kaempferol, luteolin, quercetin, luteoloside, buddleoside) present in Chrysanthemum morifolium Ramat. from different cultivars (Chuju, Gongju, Hangju, Boju). The results indicated a good repeatability and sensitivity for the quantification of the five analytes with RSDs for overall precision lower than 3%. The limits of detection ranged from 0.73 to 2.34 μg/mL, while the limits of quantification were between 2.19 and 5.86 μg/mL. The method showed that SFC could be employed as a useful tool for the quality assessment of Traditional Chinese medicines (TCMs) containing flavonoids as active components. [less ▲]

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See detailStudy of the outer membrane permeability of Pseudomonas aeruginosa to ß-lactam antibiotics
Amisano, Francesco ULiege; Silvestri, Mauro ULiege; Mercuri, Paola ULiege et al

Poster (2017, June 17)

Background The resistance of Gram negative bacteria toward β-lactam antibiotics is caused by the interplay between four independent factors: i) the alteration of the sensitivity of the target enzymes, the ... [more ▼]

Background The resistance of Gram negative bacteria toward β-lactam antibiotics is caused by the interplay between four independent factors: i) the alteration of the sensitivity of the target enzymes, the penicillin-binding proteins, ii) the properties and concentration of the periplasmic β-lactamases, iii) the permeability of the outer membrane, iv) the efficiency of the active efflux system. On this basis, Zimmermann and Rosselet [1] proposed a model yelding a quantitative prediction of the MICs for gram-negative bacteria which was successfully applied to Escherichia coli and Enterobacter cloacae. This model seems to be less suitable in Pseudomonas aeruginosa due to its low outer membrane permeability which is mostly influenced by both a remarkable reduction of functional porins expression and an over-expression of efflux systems [2]. This decreased permeability causes difficulties in obtaining permeability coefficient direct measures. Moreover, the few published coefficients for P. aeruginosa are highly variable. For this purpose, BlaR-CTD, the C-terminal domain of a highly sensitive penicillin binding protein from Bacillus licheniformis, expressed in the periplasmic space, has been used in order to directly determinate of the concentrations of different β-lactams in this cell compartment and, consequently to obtain reliable measures of the permeability coefficient [3]. Methods P. aeruginosa PAO1 cells were incubated with different β-lactams, whose penetration into the periplasm is rapidly followed by the formation of a stable complex with BlaR-CTD. This latter was quantified in cells lysate by densitometric analysis, countermarking the free BlaR-CTD with a fluorescent β-lactam. The excess of the antibiotics will be hydrolysed by the addition of a class B β-lactamase. We used the same protocol for P. aeruginosa TNP004 [4], a PAO1 strain with a selective deletion of OprD porin, in order to study the influence of this single mutation for the antibiotic permeability. Results By the approach described above we determined the permeability coefficients of the external membrane of P. aeruginosa for different antibiotics belonging to the penicillin, cephalosporin and carbapenem sub-families. The comparison with the porin mutant strain showed similar coefficients for all the antibiotic tested except, as expected, for Imipenem Conclusion This work allowed a preliminary characterization of antibiotic permeability in P. aeruginosa which was poorly studied until now. Furthermore, we could apply this method to correlate the permeability with the role of porin deletions and/or efflux pumps overexpression in antibiotic resistant strains of clinical relevance. References 1 Zimmermann, W. and A. Rosselet. 1977. Function of the outer membrane of Escherichia coli as a permeability barrier to beta-lactam antibiotics. Antimicrob. Agents Chemother. 12:368–372. 2 Livermore D. M., and K. W. M. Davy. 1991. Invalidity for Pseudomonas aeruginosa of an accepted model of bacterial permeability to β-lactam antibiotics. Antimicrob. Agents Chemother. 35:916-921. 3 Lakaye B., Dubus A., Joris B., and J.M. Frère. 2002. Method for estimation of low outer membrane permeability to β-lactam antibiotics. Antimicrob. Agents Chemother. 46:2901-2907. 4 Yoneyama H., Yamano Y and T. Nakae. 1995 Role of porins in the antibiotic susceptibility of Pseudomonas aeruginosa: construction of mutants with deletions in the multiple porin genes. Biochem Biophys Res Commun. 213:88-95. [less ▲]

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See detailPanel moderator: enforcement and remedies
Van Cleynenbreugel, Pieter ULiege

Scientific conference (2017, June 17)

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See detailENMG du pied (atelier)
WANG, François-Charles ULiege

Conference (2017, June 17)

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See detailLe cours de philosophie et terminale, un lieu intermédiaire entre le domaine privé et le domaine public ? Une interprétation arentienne d'une expérience du savoir
Glorie, Caroline ULiege

in Implications Philosophiques (2017)

Partant du constat que la classe est traversée par une dimension politique (le programme de cours est fixé par le Ministère de l’Éducation nationale et vise à préparer les élèves à adopter les valeurs du ... [more ▼]

Partant du constat que la classe est traversée par une dimension politique (le programme de cours est fixé par le Ministère de l’Éducation nationale et vise à préparer les élèves à adopter les valeurs du citoyen), cet article cherche, dans un premier temps, à en tirer les conséquences concrètes. À l’aide d’une description critique de ce qui se joue en classe, ce premier moment vise à montrer que l’idéal politique qui sous-tend l’enseignement de la philosophie en Terminale a pour conséquence d’imposer une vision du monde « du dehors », ce monde des adultes auquel l’école doit préparer, comme un monde unifié. La manière dont le cours de philosophie doit se donner rejoue sans cesse le présupposé d’un monde non conflictuel. Ensuite, dans un second temps, cet article vise à interroger la nécessité de faire de la classe un lieu séparé du monde des adultes à l’aide des réflexions d’Hannah Arendt sur la dimension privée et sociale de l’école. Comment la classe peut-elle être un espace traversé par la pluralité au sens où l’entend Arendt alors même qu’il s’agit d’un espace privé ? [less ▲]

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