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See detailEvaluation of the promethazine and acepromazine sedative and hemodynamic effects and norepinephrine reversal of acepromazine induced hemodynamic alterations in the standing horse
De Araujo Pequito, Manuel ULg

Doctoral thesis (2015)

Some phenothiazine derivates, such as acepromazine (ACP), have beneficial properties that could be interesting in equine patients with systemic inflammatory diseases where neutrophil activation and ROS ... [more ▼]

Some phenothiazine derivates, such as acepromazine (ACP), have beneficial properties that could be interesting in equine patients with systemic inflammatory diseases where neutrophil activation and ROS production are implicated. Besides, ACP’s vasodilatatory properties can also be of clinical importance in conditions such as acute laminitis or in anaesthetic protocols. However, the vasodilation induced by ACP is contraindicated in horses suffering from hypotension, a typical complication of systemic inflammatory diseases in horses. The sedative effect of ACP can also have an impact on the correct evaluation of the mental state of a horse in intensive care. Hence, it could be important either to select another phenothiazine derivate with the same beneficial effects as ACP, but with fewer undesirable effects, or to create a medication protocol, in which ACP is associated to another molecule, with the purpose of diminishing its undesired effects. Therefore, this work focused on the comparison of the sedative and peripheral hemodynamic effects of ACP and promethazine (PTZ) as well as on the evaluation of the hemodynamic effects of the administration of ACP followed by a norepinephrine (NOR) infusion in the standing healthy horse. To achieve this objective, 3 different studies were designed. The first one focused on the comparison between ACP and PTZ and the two other ones focused on the study of the association between ACP and NOR. In the first experimental protocol, 9 healthy Warmblood horses randomly received either intravenous ACP at 0.1 mg/kg or PTZ at 0.1, 0.2 or 0.3 mg/kg. A sedation score based on clinical examination was recorded, and systolic arterial blood pressure (SAP) was noninvasively evaluated using a Doppler flow detector at the tail, just before and every 15 minutes until 60 minutes after drug injection. Hemodynamics of the median artery of the left forelimb was studied using Doppler ultrasonography just before and 45 minutes after injection of the drug, which allowed calculation of surface (SURF), diameter (DIAM), and circumference (CIRC) of the vessel, as well as peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (MV), volumetric flow (VF), and resistivity index (RI) of the blood flow. In the second experimental protocol, an infusion of NOR at a constant rate of 1 μg/kg/minute for 15 minutes was administered to 5 standing healthy horses 45 minutes (TACP+45) after intravenous injection of ACP at 0.1 mg/kg. Non-invasive SAP and the same hemodynamic parameters than in study 1 were evaluated on the median artery. The SAP was evaluated before, 15, 30, 45 and every 5 minutes during the NOR infusion (TNORa, TNORb, TNORc) from TACP+45 to 60 minutes (TACP+60) after ACP administration and at 5 (TACP+65), 15 (TACP+75), 30 (TACP+90) and 45 (TACP+105) minutes after stopingt the NOR infusion. In the third experimental protocol, 45 minutes after ACP intravenous injection at 0.1 mg/kg, a continuous NOR infusion was performed during 10 minutes at 0.3 μg/kg/min, then 10 minutes at 0.5 μg/kg/min, and finally 10 minutes at 1 μg/kg/min in 5 standing healthy horses. Cardiac output (CO), stroke volume (SV) and systemic vascular resistance (SVR) were measured using lithium dilution (LiDCO). The mean (MAP), systolic and diastolic (DAP) systemic arterial pressures were measured invasively using an anesthesic monitoring system, that also automatically calculated the heart rate (HR). All parameters were measured immediately before ACP administration, 45 minutes after, at the end of each incremental 10 minutes NOR continuous infusion rate (TNOR0.3, TNOR0.5 and TNOR1) and ten minutes after terminating the NOR infusion. Regardless of the used dose, PTZ had lesser sedative and hypotensive effects than ACP at 0.1 mg/kg and did not induce significant variations in SURF, DIAM, CIRC, PSV, EDV, MV, VF, and RI of the studied standing horses. Conversely, the vasodilatory and hypotensive properties of ACP were illustrated by a significant increase in SURF, DIAM, CIRC, PSV, EDV, MV, and VF and a significant reduction of the RI and SAP. Unlike ACP, PTZ did not induce alterations on the morphology of the Doppler waveform. All the ACP-induced hemodynamic alterations, with the exception of PSV and MV were significantly counteracted by the NOR infusion at a constant 1 μg/kg/minute rate, from TNORa to TNORc for EDV, VF, MV and RI, and to TACP+65 for SAP, from TNORb to TACP+90 for CIRC and SURF and to TNORc for DIAM. Besides, although the ACP induced hypotension, no significant changes were observed in the CO, SV, SVR and HR. NOR infusion at incremental doses counteracted the decrease of SAP, from TNOR0.3 to TNOR1, of MAP at TNOR0.3 and TNOR1 and of DAP at TNOR1. After the ending of the infusion, the arterial pressure again dropped significantly, the CO and HR increased non significantly, and the SVR decreased non significantly. PTZ appears to have less sedative and peripheral vasodilator effects than ACP, thus it could be safer than ACP in patients suffering from hypotension. The results also demonstrate that a NOR infusion can reverse ACP’s vasodilatory effects, restoring hemodynamic parameters and blood pressure in horses. The studied NOR infusion proved hence to be useful in horses suffering from vasodilation and hypotension, as it reverted the hemodynamic alterations induced by ACP. [less ▲]

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See detailPhytoplankton abundance and diversity in the Congo river at high and low waters
Stoyneva, MP; Descy, JP; Bouillon, S et al

Conference (2015, July 05)

Detailed reference viewed: 32 (0 ULg)
See detailLes futurs discontinus de l’anticipation : strates, réversions et ruptures temporelles
Stienon, Valérie ULg

Scientific conference (2015, July 03)

La qualité du récit d’anticipation est souvent estimée à la mesure de ses coïncidences avec les données du monde de référence. Cette lecture factuelle tend à prévaloir pour la réception des genres de ... [more ▼]

La qualité du récit d’anticipation est souvent estimée à la mesure de ses coïncidences avec les données du monde de référence. Cette lecture factuelle tend à prévaloir pour la réception des genres de l’imaginaire du futur, dans lesquels on décèle volontiers tantôt une fonction prédictive – cognitive ou de mise en garde –, tantôt un éloignement dépaysant avec les réalités connues. On a moins considéré les temporalités internes de ces récits, tout aussi intéressantes que leur mise en relation avec les données du monde. Les chronologies diégétiques et les visions de l’Histoire sur lesquelles ils reposent montrent que ces mondes fictifs entretiennent avec leur propre temporalité – passée, présente et future – des rapports pour le moins complexes, faits de nombreux décrochages et d’emboîtements divers. Comment le roman d’anticipation les aménage-t-il, les comble-t-il, voire les justifie-t-il dans le cadre de son dispositif narratif ? À partir d’exemples empruntés à une histoire littéraire de l’anticipation française encore peu connue pour la période 1840-1940 (Souvestre, Henriot, Messac, Paulin, etc), on examinera quelques manières romanesques de questionner le cours du temps et de remettre en question une chronologie linéaire téléologique. En particulier, les cas de figures suivants seront détaillés : • strates : rétrofuturisme convoquant une double temporalité future, dont l’une contient l’autre • réversions : vision cyclique de l’Histoire associée à une involution ou un déclin • ruptures : mondes possibles hors temps, sans passé ou à la temporalité bouclée [less ▲]

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See detailAFM for monitoring the elongation of amyloid fibrils made of polyQ proteins
Willet, Nicolas ULg; Bastin, Frédérique ULg; Dorval, Frédéric ULg et al

Scientific conference (2015, July 02)

Several neurodegenerative disorders, called polyglutamine (polyQ) diseases, are associated with the aggregation into amyloid fibrils of proteins containing an expanded polyQ tract (>35-45 Q). Amyloid ... [more ▼]

Several neurodegenerative disorders, called polyglutamine (polyQ) diseases, are associated with the aggregation into amyloid fibrils of proteins containing an expanded polyQ tract (>35-45 Q). Amyloid fibrils are proteinaceous aggregates with a helical organization. Such assemblies contain a large amount of b-sheet secondary structures. How do non-polyQ regions of the proteins interfere with the propensity of polyQ tracts to trigger fibril formation? The aim of this study is a better understanding of the role of polyQ and non-polyQ regions on the elongation of amyloid fibril. By performing fibril elongation in the presence of various chimeras and in different conditions, the aim is to unravel the effect of each parameter in general, and of the protein context in particular, on the elongation rate. This requires AFM imaging in complement to QCM experiments. Imaging parameters have to be optimized for such sensitive and nanosized samples. Accurate measurement of fibril elongation rate is performed by quartz crystal microbalance (QCM) and sensor surfaces are imaged by atomic force microscopy (AFM) before and after the elongation step. BlaP is an ideal host protein, in order to better understand how non-polyQ regions interfere with the aggregation process of polyQ proteins. BlaP chimeras are a good model system because there is a Q-treshold for fibril formation ; the longer the polyQ, the faster the aggregation ; conformation and insertion site are critical. [less ▲]

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See detailSurveillance à long terme de l'atmosphère terrestre depuis la station du Jungfraujoch
Mahieu, Emmanuel ULg

Conference (2015, July 02)

Nous présentons une vue d'ensemble des activités menées par les chercheurs de l'Université de Liège à la station scientifique internationale du Jungfraujoch, depuis les observations infrarouges pionnières ... [more ▼]

Nous présentons une vue d'ensemble des activités menées par les chercheurs de l'Université de Liège à la station scientifique internationale du Jungfraujoch, depuis les observations infrarouges pionnières effectuées à ce site par le Pr Migeotte en 1950-1951. L'accent est mis sur les données géophysiques et les séries temporelles déduites pour les constituants de l'atmosphère influençant le climat. [less ▲]

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See detailPolarization alignments of quasars from the JVAS/CLASS 8.4-GHz surveys
Pelgrims, Vincent ULg; Hutsemekers, Damien ULg

in Monthly Notices of the Royal Astronomical Society (2015), 450

We test the hypothesis that the polarization vectors of flat-spectrum radio sources (FSRSs) from the JVAS/CLASS 8.4-GHz surveys are randomly oriented in the sky. A sample with robust polarization ... [more ▼]

We test the hypothesis that the polarization vectors of flat-spectrum radio sources (FSRSs) from the JVAS/CLASS 8.4-GHz surveys are randomly oriented in the sky. A sample with robust polarization measurements is made with 4155 objects. Redshift information is known for 1531 of them. We performed two statistical analyses: one in two dimensions and the other in three dimensions when distance is available. We find significant large-scale alignments of polarization vectors for samples containing only quasars among the varieties of FSRS. While these correlations prove difficult to explain either by a physical effect or by biases in the data set, that the quasars that have significantly aligned polarization vectors are found in regions of the sky where optical polarization alignments were previously found is striking. [less ▲]

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See detailComposite hydraulic modeling to design a complex dam spillway
Erpicum, Sébastien ULg; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

Conference (2015, July 01)

The paper presents the application of a composite hydraulic modeling approach to the rehabilitation studies of a complex dam spillway. First, a physical scale model of the existing works has been built ... [more ▼]

The paper presents the application of a composite hydraulic modeling approach to the rehabilitation studies of a complex dam spillway. First, a physical scale model of the existing works has been built and operated. It enabled to define very accurately the actual discharge capacity and to validate a numerical model of the system. Second, the numerical model has been used to rapidly test several rehabilitation solutions. Finally, the final design has been validated and optimized using the physical model. The paper shows how composite hydraulic modeling enables to combine the inherent advantages of physical and numerical modeling approaches, which are complementary, while being beneficial to the delay as well as the quality of the analysis. [less ▲]

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See detailQuantitatively mimicking wet colloidal suspensions with dry granular media
Messina, René; Aljawhari, Sarah; Bécu, Lydiane et al

in Scientific Reports (2015)

Athermal two-dimensional granular systems are exposed to external mechanical noise leading to Brownian-like motion. Using tunable repulsive interparticle interaction, it is shown that the same ... [more ▼]

Athermal two-dimensional granular systems are exposed to external mechanical noise leading to Brownian-like motion. Using tunable repulsive interparticle interaction, it is shown that the same microstructure as that observed in colloidal suspensions can be quantitatively recovered at a macroscopic scale. To that end, experiments on granular and colloidal systems made up of magnetized particles as well as computer simulations are performed and compared. Excellent agreement throughout the range of the magnetic coupling parameter Γ is found for the pair distribution as well as the bond-orientational correlation functions. This finding opens new ways to efficiently and very conveniently explore phase transitions, crystallization, nucleation, etc in confined geometries. [less ▲]

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See detailSuppression of simulated self-excited oscillation using smart materials on flexible wing structure
Abdul Razak, N.; Nasip, N. S.; Hawari, A. F. et al

in Proceedings of the International Forum on Aeroelasticity and Structural Dynamics, IFASD 2015 (2015, July 01)

Suppression of simulated self-excited oscillation due to aeroelastic effects using piezoelectric patches is reported. The focus of the present work is suppressing simulated flutter oscillation using ... [more ▼]

Suppression of simulated self-excited oscillation due to aeroelastic effects using piezoelectric patches is reported. The focus of the present work is suppressing simulated flutter oscillation using piezoelectric patches bonded to the wing structure. First, a clean wing is exposed to airflow in the wind tunnel where it experienced limited amplitude oscillation. The responses were recorded. This is followed by bonding piezoelectric patches to the identical wing that was tested in the wind tunnel. Two of the patches were used as actuators to simulate self-excited oscillation in a control manner. The selected mode for excitation is 1st bending mode. The other two patches were used as suppressor for active control using negative velocity feedback Single-Input, Single-Output approach. The single input signal for negative feedback is also sensed using piezoelectric patches. The controller manages to suppress the simulated flutter response to a lower oscillation amplitude values. This works demonstrated the used of piezoelectric material as actuator to reproduce the oscillation amplitude during self-excited oscillation and suppress the oscillation at the same time. [less ▲]

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See detailFrom the ocean to a reef habitat: How do the larvae of coral reef fishes find their way home? A state of art on the latest advances
Barth, P; Berenshtein, I; Besson, M et al

in Vie et Milieu (2015), 65(2), 91-100

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See detailEtude de l'évolution de l'enneigement dans les Hautes Fagnes (Belgique) au cours des cinquante dernières années à l'aide du modèle climatique régional MAR
Wyard, Coraline ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

in Erpicum, Michel (Ed.) Actes du XXVIIIe colloque annuel de l’Association Internationale de Climatologie : Modélisations et variabilités (2015, July)

The “Modèle Atmosphérique Régionale” MAR is a regional climate model originally developed to study the polar ice sheets. In this study, the MAR model has been adapted to Belgium in order to study the snow ... [more ▼]

The “Modèle Atmosphérique Régionale” MAR is a regional climate model originally developed to study the polar ice sheets. In this study, the MAR model has been adapted to Belgium in order to study the snow cover evolution of the High Fens (east of Belgium), a region covered by snow on average one to two months per year. As validation, we have sucessfully compared MAR based daily snow heights with snowcam-based and/or laser sensor-based observations over the period 2008-2013. Then, the model has been forced by ERA-Interim since 1958 to study the snow cover evolution during the last fifty years at the summit of Belgium. The results show no significant trend despite global warming. [less ▲]

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See detailGlucosinolates and by-products in rapeseed meal related to hydrothermal processing
Quinsac, A.; Carré, P.; Fauconnier, Marie-Laure ULg et al

Poster (2015, July)

Background: For safety reasons, rapeseed meal (RSM) is usually desolventized with strong hydrothermal treatments, leading to various levels of residual glucosinolates (GSL), and protein solubility. The ... [more ▼]

Background: For safety reasons, rapeseed meal (RSM) is usually desolventized with strong hydrothermal treatments, leading to various levels of residual glucosinolates (GSL), and protein solubility. The RSM nutritional quality may be then lowered for monogastrics, due to GSL breakdown products whose reliable and “easy to use” indicators lack. [less ▲]

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See detailStructural optimization of multibody system components described using level set techniques
Tromme, Emmanuel ULg; Tortorelli, Daniel; Bruls, Olivier ULg et al

in Structural and Multidisciplinary Optimization (2015)

The structural optimization of the components in multibody systems is performed using a fully coupled optimization method. The design’s predicted response is obtained from a flexible multibody system ... [more ▼]

The structural optimization of the components in multibody systems is performed using a fully coupled optimization method. The design’s predicted response is obtained from a flexible multibody system simulation under various service conditions. In this way, the resulting optimization process enhances most existing studies which are limited to weakly coupled (quasi-) static or frequency domain loading conditions. A level set description of the component geometry is used to formulate a generalized shape optimization problem which is solved via efficient gradient-based optimization methods. Gradients of cost and constraint functions are obtained from a sensitivity analysis which is revisited in order to facilitate its implementation and retain its computational efficiency. The optimizations of a slider-crank mechanism and a 2-dof robot are provided to exemplify the procedure. [less ▲]

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See detailDe nationaliteit van Belgische ‘jihadisten’ op de schopstoel : wanneer worden ‘nieuwe’ Belgen ‘echte’ Belgen?
Wautelet, Patrick ULg

Conference (2015, July)

This presentation first gives an overview of the current legal standards for deprivation of nationality based on terrorism in Belgium and France. In a second part, it focuses on the question whether it ... [more ▼]

This presentation first gives an overview of the current legal standards for deprivation of nationality based on terrorism in Belgium and France. In a second part, it focuses on the question whether it may be justified to treat different categories of nationals differently in nationality law and more specifically when dealing with deprivation of nationality. An attempt is made to analyze the French and Belgian legal framework from the angle of the prohibition of discrimination. [less ▲]

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See detailHybrid inventory, gravimetry and altimetry (HIGA) mass balance product for Greenland and the Canadian Arctic
Colgan, W.; Abdalati, W.; Citterio, M. et al

in Remote Sensing of Environment (2015), 168

We present a novel inversion algorithm that generates a mass balance field that is simultaneously consistent with independent observations of glacier inventory derived from optical imagery, cryosphere ... [more ▼]

We present a novel inversion algorithm that generates a mass balance field that is simultaneously consistent with independent observations of glacier inventory derived from optical imagery, cryosphere-attributed mass trends derived from satellite gravimetry, and ice surface elevation trends derived from airborne and satellite altimetry. We use this algorithm to assess mass balance across Greenland and the Canadian Arctic over the Sep-2003 to Oct- 2009 period at 26 km resolution. We evaluate local algorithm-inferred mass balance against forty in situ point observations. This evaluation yields an RMSE of 0.15 mWE/a, and highlights a paucity of in situ observations from regions of high dynamic mass loss and peripheral glaciers. We assess mass losses of 212 ± 67 Gt/a to the Greenland ice sheet proper, 38 ± 11 Gt/a to peripheral glaciers in Greenland, and 42 ± 11 Gt/a to glaciers in the Canadian Arctic. These magnitudes of mass loss are dependent on the gravimetry-derived spherical harmonic mass trend we invert. We spatially partition the transient glacier continuity equation by differencing algorithm-inferred mass balance from modeled surface mass balance, in order to solve the horizontal divergence of ice flux as a residual. This residual ice dynamic field infers flux divergence (or submergent flow) in the ice sheet accumu- lation area and at tidewater margins, and flux convergence (or emergent flow) in land-terminating ablation areas, which is consistent with continuum mechanics theory. [less ▲]

Detailed reference viewed: 60 (3 ULg)