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See detailDéveloppement de nouvelles méthodes de marquage au fluor-18 pour peptides et oligonucléotides en vue de leur études par tomographie par émission de positons
Flagothier, Jessica ULg

Doctoral thesis (2014)

Positron Emission Tomography is a highly sensitive imaging technique currently available in nuclear medicine for diagnostic. In regard to his physical and nuclear characteristics, fluorine-18 appears ... [more ▼]

Positron Emission Tomography is a highly sensitive imaging technique currently available in nuclear medicine for diagnostic. In regard to his physical and nuclear characteristics, fluorine-18 appears often as the radionuclide of choice for the preparation of short-lived positron-emitter radiotracers for PET studies. The fluorine-18 labelling reaction for biomolecules requires very mild conditions. The current method for highly efficient fluorine-18 labelling of biomolecules is the conjugation of a [18F]prosthetic group with a reactive function on the organic compound. During this thesis, two techniques were developed to label biomolecules via a [18F]prosthetic group: the first one to label tyrosine-containing peptides and the second one to label a siRNA. The first part of this work present the synthesis of the [18F]F-PTAD which is a agent for specific radiolabelling of tyrosine. [18F]F-PTAD was coupled with a tyrosine with a global radiochemical yield (synthesis, coupling, purification) of 20% (DC) and the synthesis lasts 2h30. During the second part of this work, two alkyne-bearing linkers were synthesized. These linkers were ligated with siRNA and then reacted with azide-bearing [18F]prosthetic group via a Huisgen cycloaddition reaction. The [18F]siRNA is then obtained with an global radiochemical yield of 12% (DC) and the synthesis lasts 2h00. In conclusion, two methods for labeling biomolecules have been developed. [less ▲]

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See detailCARACTÉRISATION DE LA DIVERSITÉ GÉNÉTIQUE DE CULTIVARS D’OIGNON (ALLIUM CEPA L.) DU NIGER EN VUE DE LEUR CONSERVATION IN SITU ET DE LEUR AMÉLIORATION
Abdou, Rabiou ULg

Doctoral thesis (2014)

Plante monocotylédone, allogame, entomophile, avec un cycle cultural annuel pour la production des bulbes, bisannuel pour celle des graines, l’oignon est l’un des légumes le plus important au Niger en ... [more ▼]

Plante monocotylédone, allogame, entomophile, avec un cycle cultural annuel pour la production des bulbes, bisannuel pour celle des graines, l’oignon est l’un des légumes le plus important au Niger en raison de son utilisation en alimentation et en médecine. Le semis en pépinière suivi d’un repiquage des planches est le mode de culture le plus fréquent chez les producteurs nigériens. Cette étude explore la diversité génétique des cultivars d’oignon du Niger. La diversité est à comprendre ici au sens de la diversité nommée, la diversité morphologique et la diversité moléculaire. Cette thèse se propose d’utiliser ces trois approches complémentaires pour identifier et caractériser les variétés et écotypes selon la perception des producteurs, de caractériser la diversité morphologique et agronomique à partir des descripteurs du genre Allium établis par Bioversity International, et d’analyser la diversité moléculaire des variétés et écotypes d’oignon du Niger à partir des marqueurs moléculaires microsatellites. Cinquante-deux écotypes nommés ont été inventoriés, mais après analyse et regroupement des synonymes, il ressort que dix-sept écotypes sont cultivés au Niger. Les principaux critères des paysans pour caractériser un écotype local sont la couleur des bulbes et la zone de provenance. Les variables quantitatives et qualitatives les plus distinctives entre les écotypes d’oignon sont la longueur et le diamètre des feuilles, le poids des bulbes, la couleur des feuilles, la forme et la couleur des bulbes, l’uniformité de la forme et de la couleur des bulbes. La distance génétique est plus grande, d’une part, entre les écotypes les plus éloignées géographiquement, et d’autre part, entre les écotypes les plus différents au niveau des caractères morphologiques. Le nombre de morphotypes varie de un à neuf par écotype testé. Les analyses moléculaires confirment la forte variabilité à l’intérieur des écotypes et les conclusions relatives à la distance génétique observée à partir des données morphologiques. A l’issue de ces travaux de caractérisation génétique de l’oignon, il est donc utile de combiner des stratégies de conservation in situ et ex situ, et l’exploitation de ces ressources génétiques pour améliorer la production et la rusticité des cultivars d’oignon du Niger. [less ▲]

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See detailEtude de l'implication de cellulases dans la voie de biosynthèse de cellulose chez les bactéries
Delsaute, Maud ULg

Doctoral thesis (2014)

By definition, cellulases are enzymes that catalyze the degradation of cellulose. However, their involvement in cellulose biosynthesis by bacteria and plants has been reported, although their exact ... [more ▼]

By definition, cellulases are enzymes that catalyze the degradation of cellulose. However, their involvement in cellulose biosynthesis by bacteria and plants has been reported, although their exact contribution remains unclear. In the present study, we have investigated the involvement of cellulases from glycoside hydrolase family 5 (GH5) in cellulose synthesis. In particular, we have functionally and structurally characterized the Ps_Cel5A cellulase from Pseudomonas stutzeri and its metagenome-derived homolog RBcel1, which both belong to the GH5 family and are suspected to be involved in cellulose biosynthesis. In addition, we have also compared these enzymes with the well-characterized Ta_Cel5A cellulase from the cellulolytic fungus Thermoascus aurantiacus. The first part of the work was devoted to the description of the tridimensional structure of RBcel1, in comparison with other glycoside hydrolases from GH5. In the second part of the study, we focused on the functional and structural comparison between RBcel1, Ps_CelA and Ta_Cel5A. Biochemical analysis has highlighted that, besides their hydrolytic activity, RBcel1 and Ps_Cel5A were able to catalyze transglycosylation in vitro. This synthesis reaction was not detected for Ta_Cel5A, which seemed to remain hydrolytic only. Determination of the structure of RBcel1 in complex with cellobiose has revealed distinct features in the aglycone substrate binding sites compared to Ta_Cel5A which could potentially explain the observed differences in their activities in vitro. Finally, the involvement of Ps_Cel5A in cellulose production by P. stutzeri was confirmed, by analysis the ability of P. stutzeri-ΔPs_Cel5A to produce the polymer. Complementation of this mutant strain by the three cellulases was also performed and discussed. [less ▲]

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See detail"'What is an incident?': Conceptual Boundaries under the Microscope"
Rossignol, Nicolas ULg

Scientific conference (2014, September 04)

Within the context of a nuclear facility, how can an event be qualified as an incident or not, depending on different definitions, either formal or corresponding to actors' own representations? In this ... [more ▼]

Within the context of a nuclear facility, how can an event be qualified as an incident or not, depending on different definitions, either formal or corresponding to actors' own representations? In this presentation, we show how different those definitions are, and we elaborate on the reasons why such a focus on conceptual boundaries is interesting in the context of "incident reporting". [less ▲]

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See detailLes effets délétères métaboliques et oxydants induits lors d'un sepsis sur la fonction rénale
Quoilin, Caroline ULg

Doctoral thesis (2014)

Acute kidney injury (AKI) is a frequent complication of sepsis that can increase mortality as high as 70%. The pathophysiology of this kidney failure was previously believed to be secondary to decreased ... [more ▼]

Acute kidney injury (AKI) is a frequent complication of sepsis that can increase mortality as high as 70%. The pathophysiology of this kidney failure was previously believed to be secondary to decreased global renal perfusion causing hypoxia-induced injury. However, new research suggests this paradigm is overly simplistic, and injury is now considered multifactorial in origin. Mechanisms that contribute to kidney injury mainly include inflammation, alterations in microvascular renal blood flow and changes in bioenergetics. To study the mechanism of oxygen regulation in acute kidney injury during sepsis, we developed a sepsis-induced in vitro model using proximal tubular epithelial cells (HK-2) exposed to a bacterial endotoxin (lipopolysaccharide, LPS). Our first investigation, by using both high-resolution respirometry and electron spin resonance spectroscopy, showed that HK-2 cells exhibit a decreased oxygen consumption rate when treated with LPS. Surprisingly, this cellular respiration alteration persists even after the stress factor is removed. We suggested that this irreversible decrease in renal oxygen consumption after LPS challenge is related to a pathologic metabolic down-regulation such as a lack of oxygen utilization by cells for ATP production. In the long term, this metabolic disturbance leads cells to a predominantly apoptotic death. To confirm this hypothesis of cytopathic hypoxia, we demonstrated that this alteration in the renal respiratory function is mainly due to an impairment in the metabolic activity of HK-2 cell mitochondria. Following LPS treatment, the oxidative phosphorylation is interrupted because of the inhibition of cytochrome c oxidase activity. As a consequence, disruptions in the electron transport and the proton pumping across the system occur, leading to a decrease of the mitochondrial membrane potential, the release of apoptotic-inducing factors and a decrease in ATP production. To clarify the mechanism by which the LPS induces mitochondrial alterations, we studied the oxidative stress generation in HK-2 cells. Interestingly, we revealed that the induction of a cytosolic oxidative stress is an event that appears before mitochondrial dysfunction in the LPS-treated HK-2 cells. This primary redox state is notably due to the activation of the two enzymes NADPH oxidase 4 and inducible NO synthase. The simultaneous production of anion superoxide and nitric oxide strongly suggests the formation of peroxynitrite, a relative stable powerful oxidant that can diffuse through mitochondrial compartments and undergo cytotoxic reactions. To our knowledge, our model reveals for the first time the role of NADPH oxidase-derived cytosolic ROS in triggering tubular cell damage. Moreover, after being first target of the oxidative stress, mitochondria become in turn producer of reactive oxygen species that carry on mitochondrial dysfunction. It seems thus that a mechanism of oxidative stress-induced redox cycling is a main cause of the mitochondrial dysfunction of LPS-treated HK-2 cells. The role of oxidants in mitochondrial dysfunction was further confirmed by the use of iNOS inhibitors or antioxidants that preserve cytochrome c oxidase activity and block mitochondrial membrane potential dissipation. Overall, these results suggest that sepsis-induced AKI should not only be regarded as failure of energy status but also as an integrated response, including transcriptional events, ROS signaling, mitochondrial activity and metabolic orientation such as apoptosis. [less ▲]

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See detailCompeting as a Luxury SME
Riguelle, France ULg; Van Caillie, Didier ULg

in Reinecke, Sven; Berghaus, Benjamin; Müller-Stewens, Günter (Eds.) The Management of Luxury (2014)

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See detailCost monitoring to promote the value added for clam raising farmers in the Northern area of Vietnam
Bui Thi, Nga; Tran Thu, Hoai; Tran Huu, Cuong et al

Conference (2014, September 02)

Clam farming in coastal provinces of Vietnam has notably developed since the last decade. It generated high income, improve socio-economic development for many local communities. However, many clam ... [more ▼]

Clam farming in coastal provinces of Vietnam has notably developed since the last decade. It generated high income, improve socio-economic development for many local communities. However, many clam raising farms are facing difficulties of farm management, disease control, markets and systems of quality control. This research aims to study about the real situation of cost monitoring in the clam raising farms in the Northern area of Vietnam and suggest some recommendation for apply a suitable model for cost monitoring to promote the value added for farmers. The paper based on the semi-structure, standard questionnaires and PRA method to collect data from 89 clam raising farms in two coastal provinces (Nam Dinh and Thai Binh) in the Northern area of Vietnam in 2014. The findings show that clam raising provides farmers a chance of getting high income parallel with high risk. There were 32.15% surveyed farms got profit, 32.14% of them met the breakeven and 35.71% was lost. The study finds out four key factors affecting farms’ economic performance and efficiency. The first is capacity of farm cost control as the cost for clam raising was very high at 8,142 to 9,190 USD per ha. The second is the farmers’ experience, skill, technique and ability of risk control. The third is low, unstable market price and unsuitable market channel with the dominant of the traders. Final factors is the area and location of clam raising. Despite of these difficulties, 55.14% surveyed farms still want to expand their production, 25% of them will continue, and only 17.86% will stop or change to other activities. In order to promote the value added for clam raising farmers, cost control should be paid more attention, improvement of the farmers’ capacity is necessary, and market should be regarded. [less ▲]

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See detailI know what you did last summer - High resolution mapping of wild boar damages with drones
Michez, Adrien ULg; Morelle, Kevin ULg; Lehaire, François ULg et al

Poster (2014, September 01)

Wild boar ability to cause important damages to agricultural lands is not anymore to be demonstrated. These damages often raise conflicts between farmers and hunters due to the associated economic losses ... [more ▼]

Wild boar ability to cause important damages to agricultural lands is not anymore to be demonstrated. These damages often raise conflicts between farmers and hunters due to the associated economic losses. Objective and accurate method for real impact assessment of losses suffered by farmers is thus needed. Currently,in Wallonia damage assessment is performed from the ground by experts, asked to evaluate precisely the area impacted. This task is time and man power consuming. Moreover, damaged areas are often large and consequently, sampling is mandatory and can induce accuracy issues. Recent development of unmanned aerial vehicle (UAV / drone) toghether with lower cost and better accessibility for civil society and scientific community, makes now possible the use of this technology for wildlife researches. Through photogrammetric 3D reconstruction of the field crop, UAV can allow to objectively and precisely measure the area impacted by wild boar damages. In a context of increasing issues caused by wild boar to agriculture, and the need for stakeholders for accurate impact assessment, we tested an innovative approach to estimate more effectively the area impacted by wild boar. [less ▲]

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See detailElastic damage to crack transition in a coupled non-local implicit discontinuous Galerkin/extrinsic cohesive law framework
Wu, Ling ULg; Becker, Gauthier ULg; Noels, Ludovic ULg

in Computer Methods in Applied Mechanics & Engineering (2014), 279

One current challenge related to computational fracture mechanics is the modeling of ductile fracture and in particular the damage to crack transition. On the one hand, continuum damage models, especially ... [more ▼]

One current challenge related to computational fracture mechanics is the modeling of ductile fracture and in particular the damage to crack transition. On the one hand, continuum damage models, especially in their non-local formulation which avoids the loss of solution uniqueness, can capture the material degradation process up to the localization of the damage, but are unable to represent a discontinuity in the structure. On the other hand cohesive zone methods can represent the process zone at the crack tip governing the crack propagation, but cannot account for the diffuse material damaging process. In this paper we propose to combine, in a small deformations setting, a non-local elastic damage model with a cohesive zone model. This combination is formulated within a discontinuous Galerkin nite element discretization. Indeed this DG weak formulation can easily be developed in a non-local implicit form and naturally embeds interface elements that can be used to integrate the traction separation law of the cohesive zone model. The method remains thus consistent and computationally e cient as compared to other cohesive element approaches. The effects of the damage to crack transition and of the mesh discretization are respectively studied on the compact tension specimen and on the double-notched specimen, demonstrating the efficiency and accuracy of the method. [less ▲]

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See detailMultilocus sequence typing analysis and antibiotic resistance of Clostridium difficile strains isolated from retail meat and humans in Belgium
Rodriguez Diaz, Cristina ULg; Taminiau, Bernard ULg; Avesani, Véronique et al

in Food Microbiology (2014), 42

Clostridium difficile has been isolated from food animals and meat, specially ground pork and ground beef. The recovered isolates were closely related to C. difficile human strains, indicating that ... [more ▼]

Clostridium difficile has been isolated from food animals and meat, specially ground pork and ground beef. The recovered isolates were closely related to C. difficile human strains, indicating that animals and food are possible transmission routes of human C. difficile infection. The main objective of this study was to characterize C. difficile isolates from retail meat and to compare with human isolates recovered from hospital patients in Belgium. Raw meat (beef and pork) was obtained from the retail trade. C. difficile was recovered from 2.3% of the beef samples and from 4.7% of the pork samples. A total of 4 different PCR-ribotypes were identified with a large percentage of types 078 and 014. Resistance to moxifloxacin and erythromycin was detected. The multi-locus sequence typing (MLST) analysis showed that meat and human isolates cluster in the same lineage. This study reveals the presence of toxigenic C. difficile in retail meat in Belgium with predominance PCR-ribotypes 078 and 014, which are among the four most prevalent ribotypes of C. difficile isolated from humans in Europe. [less ▲]

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See detailSelecting job candidates who have a propensity to exhibit change-oriented organizational citizenship behaviour.
Lothe, Benoit ULg; Hansez, Isabelle ULg

Conference (2014, September)

Purpose An abundant literature indicates that Organizational Citizenship Behaviours (OCBs) positively influence a number of important organizational outcomes. Furthermore, research is needed on the topic ... [more ▼]

Purpose An abundant literature indicates that Organizational Citizenship Behaviours (OCBs) positively influence a number of important organizational outcomes. Furthermore, research is needed on the topic of assessing and selecting applicants who have a propensity to exhibit OCB (Organ & al., 2010). Some of these behaviours are truly important to enable organization to adapt and “to make constructive changes in the work and task environment” (Choi, 2007, p.468). Examples include Voice, a challenging dimension of OCB (Dominguez & al., 2013), and Sportsmanship, that facilitate the change by reducing the diversion of resources in trivial matters (Organ & al., 2006). This exploratory study provides empirical evidence about using Situational Judgment Tests (SJTs) for identifying applicants who have a propensity to exhibit change oriented OCB. Method Two SJTs were developed to comply with OCBs assessment. The OCBs framework includes behaviours relating to organizational adaptation (sportsmanship) and change (voice). OCBs were concurrently collected using self-reported measurement scales. Data were collected from 220 white collars and 139 university students through an online survey. Results Significant correlations were found between the SJT scores and overall OCB ratings. More specifics findings provided substantial evidence for the concurrent validity of the SJTs to measure change-oriented sub-dimensions of OCBs. Conclusions Researches on techniques to predict OCBs are scarce and this study is the first to address the development and validation of a SJT for the assessment of affiliative and challenging dimensions of OCBs. [less ▲]

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See detailA Multiphysics model of neotissue growth in a perfu sion bioreactor
Guyot, Yann ULg; Papantoniou, Ioannis; Schrooten, Jan et al

Conference (2014, September)

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See detailL’impact de certains choix didactiques sur la performance en expression écrite et l’efficacité du feedback correctif
Noiroux, Kevin ULg; Simons, Germain ULg

in Babylonia (2014)

Many teachers use written corrective feedback, a teaching practice that consists in correcting the lexico-grammatical errors of the student’s written production. Due to its time-consuming nature for the ... [more ▼]

Many teachers use written corrective feedback, a teaching practice that consists in correcting the lexico-grammatical errors of the student’s written production. Due to its time-consuming nature for the teacher, it makes sense to strive to make corrective feedback as effective as possible. In this exploratory study, we collaborated with a high school teacher of Federation Wallonia-Brussels to create a didactic sequence that aimed at assessing the efficacy of corrective feedback in a fifth-year class. Students’ answers to a survey, as well as their written production performance, seem to point out that some pedagogical choices may have had a negative impact on the performance of corrective feedback. We underline (1) the lack of lexico-grammatical training exercises, (2) the absence of testing on lexico-grammatical knowledge, (3) the lack of work on ideas that can be transferred to the final production, (4) the lack of work on the text type and (5) the limits of formative assessment. The underlying assumption is that students’ written production performance, hence the efficacy of corrective feedback, can be improved through those didactic choices. [less ▲]

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See detailComentário sobre o artigo de Pizzanelli
Jamoulle, Marc ULg

in Revista Brasileira de Medicina de Família e Comunidade (2014), 9(31),

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See detailUse of Inertial Measurement Unit of a Mobile Device to Discriminate Cattle Grazing and Ruminating Behaviours on Pasture
Andriamandroso, Andriamasinoro ULg; Bindelle, Jérôme ULg; Lebeau, Frédéric ULg

in Animal Production in Australia (2014, September)

Precision livestock farming is emerging in the wake of the technological developments in remote sensing and motion monitoring. Tools are developed to allow accurate real time monitoring of the individual ... [more ▼]

Precision livestock farming is emerging in the wake of the technological developments in remote sensing and motion monitoring. Tools are developed to allow accurate real time monitoring of the individual cattle behaviour in a quest to improve the management of pastures. Studies have shown the relevancy of accelerometers in the analysis of behaviour using dedicated devices. Accelerometers are located either close to the mouth or jaw of the animal or on its forehead or neck. Records are usually performed at low frequency (<1Hz) and most studies classify behaviours using neuronal networks or multivariate statistical approaches, with little consideration to the animals’ actual movements. Inertial measurement units (IMU) in consumer mobile devices are specifically developed to record accurately user movements. Besides 3D-accelerometer, they can include 3-D rotational speed sensors, 3-D magnetometers and GPS. Optimised power consumption offers significant autonomy. Data directly acquired from the sensors and IMU signals from build-in proprietary algorithms can be recovered using user-friendly low-cost applications. Moreover, mobile devices can store or communicate information by wireless in real time at high frequency. As movements of cattle are in the same range as humans, this study investigates the relevancy of mobile devices IMU signals to discriminate main behaviours of cattle on pasture. [less ▲]

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