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See detailOrganocobalt complexes as source of radicals for the controlled polymerization of unconjugated monomers
Demarteau, Jérémy ULg; Cordella, Daniela ULg; Kermagoret, Anthony et al

Poster (2016, September 12)

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See detailSynthesis and characterizations of non-isocyanate polyurethane (NIPU) hydrogels
Gennen, Sandro ULg; Grignard, Bruno ULg; Thomassin, Jean-Michel ULg et al

Poster (2016, September 12)

Polyurethane (PU) is on of the most used polymers for the preparation of hydrogels due to its good biocompatibility, biodegradation and excellent mechanical properties. PU hydrogels are found in lot of ... [more ▼]

Polyurethane (PU) is on of the most used polymers for the preparation of hydrogels due to its good biocompatibility, biodegradation and excellent mechanical properties. PU hydrogels are found in lot of applications such as wound dressing, soft contact lenses, drug delivery and scaffolds for tissue engineering. Classicaly, PU is produced by a step-growth polymerization between diols and diisocyanates. However, in order to avoid the use of harmful isocyanates compounds and because of regulations which tend to ban the use of isocyanates, we developed hydrogels based on a non-isocyanate polyurethane (NIPU) chemistry by valorizing CO2-sourced cyclic carbonates and amines. Precisely, NIPU hydrogels were prepared by a solvent-free copolymerization between bifunctional hydrophilic polyethylene glycol cyclic carbonates and diamines in presence of a triamine as a crosslinker, followed by a water swelling of the obtained cross-linked gel. Parameters such as the cross-linking ratio and diamine’s nature were optimized. Different clay contents (cloiste 30B) as nanofiller were dispersed in the ideal cyclic carbonate/diamine/triamine formulation prior polymerization in order to reinforce the compression properties of NIPU hydrogels. Finaly, we were able to prepare NIPU hydrogels with water content up to 80 % and good compression properties using low clay content. [less ▲]

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See detailPolyphosphoester containing amphiphilic block copolymers as drug nanocarriers
Ergül, Zeynep ULg; Vanslambrouck, Stéphanie; Thiry, Justine ULg et al

Poster (2016, September 12)

The design of drug delivery systems often requires biodegradable and biocompatible materials that allow safe retention and controlled release of the drug. In this respect, supramolecularly self-assembled ... [more ▼]

The design of drug delivery systems often requires biodegradable and biocompatible materials that allow safe retention and controlled release of the drug. In this respect, supramolecularly self-assembled amphiphilic block copolymers into spherical micelles are appropriate carriers for poorly soluble drugs. In that framework, we have designed novel functional poly(ethylene oxide)-b-polyphosphoester amphiphilic block copolymers able to cross-linked under UV and degrade in response to a reduction of the pH from neutral conditions. Therefore, an unsaturated alkene side-chain was introduced on the cyclic phosphate monomer according to a one-step reaction followed by its organocatalyzed polymerization initiated by a poly(ethylene oxide) macroinitiator. After self-assembly into water, the micelles were cross-linked by UV irradiation. Then, these cross-linked micelles have been loaded by doxorubicin, i.e. a drug used in cancer therapy. We observed that the doxorubicin loading increased with the number of double bonds on the polyphosphate block of non-cross-linked micelles. This diblock amphiphilic copolymer bearing pendant unsaturations appears thus particularly promising candidate to build micellar drug delivery systems for intravenous injection. [less ▲]

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See detailPAI Annual Meeting
Ouhib, Farid ULg; Aqil, Abdelhafid ULg; Dirani, Ali et al

Poster (2016, September 12)

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See detailSelf-defining memories and future projections as a means to facilitate reflection on life values in depressed adults: A preliminary study
Wagener, Aurélie ULg; Brouette, Béatrice ULg; Blairy, Sylvie ULg

Poster (2016, September 10)

Introduction. In the Brief Behavioral Activation Treatment for Depression, depressed patients are lead to a reflection on their personal values per life domains (e.g., family relationships, employment ... [more ▼]

Introduction. In the Brief Behavioral Activation Treatment for Depression, depressed patients are lead to a reflection on their personal values per life domains (e.g., family relationships, employment). The aim of this reflection is to tailor behavioral assignments through valued activities. This reflection is usually difficult for depressed patients. The current study hypothesized that exercises on autobiographical memories might act as a means to facilitate the reflection on personal values. In this perspective, self-defining memories (SDMs) and self-defining future projections (SDFPs) appear to be particularly relevant. SDMs and SDFPs concern reflections on the past and on the potential future central goals, values and conflicts of one’s life. SDMs and SDFPs are vivid and well-rehearsed autobiographical memories related to a meaning-making (i.e., a learned lesson about oneself, others or the world). The emotional valence of SDMs and SDFPs can either be positive, neutral or negative. Further, SDMs and SDFPs can consist in either specific events or categorical ones. Due to the relevance of these memories for the self, it is to be expected that recalling SDMs and imagine SDFPs will help individuals to have a clearer view of their personal values which in turn might facilitate the selection of valued activities. Further, it is hypothesized that these exercises might decrease depression and disturbances of psychological processes (i.e., rumination, self-concept clarity, environmental satisfaction). Therefore, this study aims were two-fold. First, it aimed at assessing the feasibility for depressed patients to recall SDMs and to imagine SDFPs per life domains. Second, it aimed at assessing the impact of these exercises on depression and psychological processes. Method. Nineteen depressed patients and 17 paired healthy controls (25-60 years) were recruited (data collection is still ongoing). This study comprises four meetings. During the first and the last meetings, participants completed self-reported assessments of depression and psychological processes. During the third and fourth meetings, participants were asked either to recall SDMs or to imagine SDFPs per life domains. SDMs and SDFPs were rated on specificity, meaning-making and emotional. The impact of these exercises was assessed on depression and psychological processes. Results. Preliminary results indicate that depressed patients are as able as healthy controls to recall SDMs and imagine SDFPs per life domains. Depressed patients recall less SDMs and SDFPs with meaning-making than healthy controls. Depressed patients report less SDMs and less SDFPs related to employment and less SDMs related to hobbies than healthy controls. Preliminary results show a decrease of depression in depressed patients only. Discussion. Even though depressed patients are as able as the healthy controls to recall SDMs and to imagine SDFPs, preliminary results highlight significant differences between depressed patients and healthy controls on SDMs and SDFPs. Preliminary results indicate that SDMs and SDFPs positively impact depression in depressed patients. Experimental and clinical implications of these findings will be discussed during the conference. [less ▲]

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See detailHow do droplets form?
Van Loo, Stéphanie ULg; Stoukatch, Serguei ULg; Kraft, Michael ULg et al

Poster (2016, September 07)

In microfluidics, flow focusing is widely used to produce water-in-oil droplets in microchannels at high frequency. We here report an experimental study of droplet formation in a microfluidic cross ... [more ▼]

In microfluidics, flow focusing is widely used to produce water-in-oil droplets in microchannels at high frequency. We here report an experimental study of droplet formation in a microfluidic cross-junction with a minimum number of geometrical parameters. We mostly focus on the squeezing regime, which is com- posed of two distinct steps : filling and pinching. The duration of each step (and corresponding volumes of each liquid phase) are analyzed. They vary according to both water and oil flow rates. These variations provide several insights about the fluid flows in both phases. We propose several scaling laws to relate the droplet volume and frequency to the flow rate of both phases. We also discuss the influence of surfactant and channel compliance on droplet formation. [less ▲]

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See detailMagnetic shielding above 1 T at 20 K with bulk, large grain YBCO tubes made by Buffer-aided Top Seeded Melt Growth.
Wera, Laurent ULg; Fagnard, Jean-François ULg; Kumar, Nambury Devendra et al

Poster (2016, September 07)

A superconducting tube can be used as an efficient magnetic shield. The best shielding performance levels are usually achieved when the tube is closed at one or both extremities. The purpose of the ... [more ▼]

A superconducting tube can be used as an efficient magnetic shield. The best shielding performance levels are usually achieved when the tube is closed at one or both extremities. The purpose of the present work is to study experimentally the shielding performance of YBCO tubes obtained by Buffer-aided Top Seeded Melt Growth fabrication process (BA-TSMG). This fabrication process enables the tube to be closed at one extremity by a cap containing the seed and there is no air gap between the cap and the tube. The shielding effectiveness is characterized by two parameters: (i) the shielding factor, defined as the ratio between the applied magnetic induction and the local magnetic induction measured inside the shield, and (ii) the threshold induction, i.e. the applied magnetic induction above which a given value of the shielding factor cannot be achieved. The magnetic shielding performances of tubes with different geometry are characterized at 77 K in liquid nitrogen. Further magnetic shielding measurements are carried out on one tube at various temperatures ranging from 20 K to 77 K using a Physical Property Measurement System (PPMS). The tubes are subjected to a quasi-static (“DC”) uniform magnetic field. A Hall probe measures the axial component of the local magnetic induction along the axis of the tube as a function of the applied magnetic induction. In order to investigate how the cap prevents the magnetic flux from penetrating inside the tube, we also characterize open tubes where the cap is removed and compare their properties to those of closed tubes. Magnetic shielding measurements show that the threshold induction increases by a factor of 9 as temperature decreases from 77 K to 20 K. Measurements also show that the presence of the cap improves the shielding performance at the closed extremity of the order of 1000 as it reduces the penetration through the open end. Near the closed extremity, a threshold induction of 1.5 T was reached at 20 K. To our knowledge this threshold induction is the best value reported so far at 20 K, and is comparable in magnitude to the record threshold inductions reported for bulk MgB2 and Bi-2212 materials at lower temperatures. These results give evidence that efficient magnetic shields can be obtained with this fabrication technique. [less ▲]

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See detailAre Christmas tree plantations a suitable habitat for farmland birds?
Gailly, Robin ULg; Paquet, Jean-Yves; Titeux, Nicolas et al

Poster (2016, September 06)

Over the last decade, nonfood perennial crops have been increasingly prevalent in European farming systems. Here, vegetation structure and crop management greatly differ from conventional crops and may ... [more ▼]

Over the last decade, nonfood perennial crops have been increasingly prevalent in European farming systems. Here, vegetation structure and crop management greatly differ from conventional crops and may likely impact farmland birds. Impacts on birds have been examined for bioenergy agricultural systems, such as miscanthus plantations and short rotation willow coppice. In Europe, the extend of Christmas tree plantations (CTP) has recently increased dramatically in farmland but their impacts on farmland birds remains largely unknown. We examined the extent to which CTP in southern Belgium alter bird species assemblages compared to traditional farmland. The presence and abundance of birds were recorded twice during a breeding season in randomly selected sites located in farmland areas with and without CTP. Results show that the conversion of traditional farmland into CTP modifies bird species assemblages and locally increases bird diversity and density without inducing biotic homogenization. This observed pattern indicates that CTP might constitute an interesting alternative habitat for farmland birds. However bird presence or abundance may be confounding indicator of habitat quality because individuals may be attracted to low-quality habitats in human modified landscapes. The European Stonechat Saxicola rubicola was chosen as a model species to investigate the quality of CTP as a breeding habitat in more details. Habitat quality in CTP was assessed with measures of reproductive success and survival. These measures were compared with those collected in traditional farmland. Although vegetation structure, field management and nest placement are highly different between habitat types, our first results suggest that CTP are not of lesser quality than traditional farmland for the European Stonechat. [less ▲]

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See detailUnusually high sea ice cover influences resource use by benthic invertebrates in coastal Antarctica
Michel, Loïc ULg; Dubois, Philippe; Eleaume, Marc et al

Poster (2016, September 05)

Antarctica currently undergoes strong and contrasted impacts linked with climate change. While the West Antarctic Peninsula is one of the most rapidly warming regions in the world, resulting in sea ice ... [more ▼]

Antarctica currently undergoes strong and contrasted impacts linked with climate change. While the West Antarctic Peninsula is one of the most rapidly warming regions in the world, resulting in sea ice cover decrease, the sea ice cover of East Antarctica unexpectedly tends to increase, possibly in relation with changes in atmospheric circulation. Changes in sea ice cover are likely to influence benthic food web structure through modifications of benthic-pelagic coupling, disruption of benthic production and/or modifications of benthic community structure (i.e. resource availability for benthic consumers). Here, we studied shallow (0-20 m) benthic food web structure on the coasts of Petrels Island (Adélie Land, East Antarctica) during an event of unusually high spatial and temporal (two successive austral summers without seasonal break-up) sea ice cover. Using stable isotope ratios of C and N and the SIAR mixing model, we examined importance of 4 organic matter sources (benthic macroalgae, benthic biofilm, sympagic algae, suspended particulate organic matter) for nutrition of dominant primary consumers and omnivores. 14 invertebrate taxa including sessile and mobile polychaetes, gastropods, bivalves, sea stars, sea urchins and sea cucumbers were studied. Our results indicate that most benthic invertebrates predominantly relied on sympagic algae. Despite its very high abundance, trophic role of benthic biofilm seemed limited. However, interpretation of data was complicated by the peculiar ecophysiological features of Antarctic invertebrates, whose very low metabolic rates could be associated to low isotopic turnover and long time to reach isotopic equilibrium with their food items. Resource use by consumers from Adélie Land markedly differed from literature data about invertebrate diet in coastal Antarctica, suggesting 1) important influence of increased sea ice cover on benthic food web structure and 2) high spatial and/or temporal variation in the feeding habits of studied organisms, likely linked with a high degree of trophic plasticity. Our results provide insights about how Antarctic benthic consumers, which have evolved in an extremely stable environment, might adapt their feeding habits in response to sudden man-driven changes in environmental conditions and trophic resource availability. [less ▲]

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See detailFeeding ecology of Southern Ocean seastars inferred from stable isotopes ratios
Le Bourg, Baptiste ULg; Blanchard, Alice; Danis, Bruno et al

Poster (2016, September 05)

The Southern Ocean is currently subjected to strong and contrasted impacts of climate change. The Western Antarctic Peninsula is one of the most rapidly warming regions of the world, resulting in sea ice ... [more ▼]

The Southern Ocean is currently subjected to strong and contrasted impacts of climate change. The Western Antarctic Peninsula is one of the most rapidly warming regions of the world, resulting in sea ice cover decreases. Increasing seawater temperature and sea ice cover reduction in Western Antarctic Peninsula and associated regions will likely impact food web functioning through temperature-related changes in consumer physiology, modifications of benthic community structure (e.g. expansion of exogenous species such as predatory crabs), modifications of benthic-pelagic coupling intensity or disruption of benthic production. Asteroids (Echinoderms) are an important group of southern benthos. This group also has a great trophic variability and is potentially more resistant than other organisms to temperature changes (Peck et al. 2008). Consequently, they will be likely impacted by modifications in food webs functioning rather by direct warming and investigating their trophic ecology is necessary to infer how climate change will impact them. In this context, the aim of this study is to use stable isotopes ratios of C, N and S to infer sea stars trophic ecology. 16 species of sea stars spanning 10 different families sampled in multiple and contrasted habitats across Subantarctic (South Georgia, South Sandwich Islands, Falkland Islands) and Antarctic (South Shetland Islands, South Orkney Islands, Western Antarctic Peninsula) locations. In total, tegument samples from 213 specimens was analysed. Diversity and plasticity of asteroid diet along Southern Ocean coasts were explored through isotopic niche parametrisation (e.g. niche width and overlap between species and/or populations; Jackson et al. 2011). The data will also be used in a larger scale research project on the trophic ecology of Antarctic sea stars. This project will notably compare trophic resources supporting asteroid communities in Western Antarctic Peninsula, where sea ice cover is decreasing, and in Terre Adélie, where sea ice cover is increasing (Parkinson & Cavalieri 2012). Ultimately, this project will help understanding which ecological processes determine how an animal group copes with environmental modifications linked to climate change. [less ▲]

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See detailContribution of Cross-linking and Ion-mobility for the study of protein and complex structures
Baumans, France ULg; Grifnée, Elodie ULg; Hage, Christoph et al

Poster (2016, September 05)

The tridimensional structures of proteins and the mapping of protein-protein interactions are precious sources of information for the understanding of their function. Different techniques such as X-ray ... [more ▼]

The tridimensional structures of proteins and the mapping of protein-protein interactions are precious sources of information for the understanding of their function. Different techniques such as X-ray cristallography or nuclear magnetic resonance are usually used to achieve this goal. In the field of mass spectrometry, several tools were also developped. The one presented here is the chemical cross-linking in which two reactive residue side chains, spatially close, are linked thanks to a bifunctional chemical, called crosslinker. Ion-mobility coupled to mass spectrometry has also been investigated for the study of cross-linked products. The first results tend to show that cross-linkers allow to fix the shape of the protein in solution, leaving it intact when analysed in the gas phase. [less ▲]

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See detailBack on Track... in 3D
Marchal, Antoine ULg; Lejeune, Philippe ULg; De Bruyn, Nico

Poster (2016, September 04)

Ecological monitoring provides basic information on population status and distribution that is crucial for conservation, research and management strategies. Studies using tracks are controversial due to ... [more ▼]

Ecological monitoring provides basic information on population status and distribution that is crucial for conservation, research and management strategies. Studies using tracks are controversial due to past misuses tainted with subjectivity. Advances in photogrammetry literally add another dimension to the recording techniques, and geometric morphometrics provides an appropriate approach for the study of track shape variation. Tracks are back on track in conservation! [less ▲]

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See detailTEACHING VETERINARY RADIOLOGY: DOES COMPARISON HELP?
Etienne, Anne-Laure ULg; Delguste, Catherine ULg; Busoni, Valeria ULg

Poster (2016, September 01)

Introduction/Purpose Comparison learning is an approach for learning complex visual tasks. As described in human medicine, by comparing radiographs with pathology and without pathology, veterinary ... [more ▼]

Introduction/Purpose Comparison learning is an approach for learning complex visual tasks. As described in human medicine, by comparing radiographs with pathology and without pathology, veterinary students could learn to discriminate relevant disease-related information to recognize the disease. We hypothesized that exposure to a training by side-by-side comparison of normal to abnormal radiographs would lead to higher visual diagnostic accuracy and possibly to a higher ability to describe the features of a known disease on canine thoracic radiographs. Material and methods Twenty veterinary students were randomly assigned to either a group that compared radiographs showing thoracic disease with normal images (group 1) or to a group that only studied abnormal radiographs (group 2). All students had their theoretical radiology teaching and 13 of them had also received the practical teaching of the study curriculum, evenly distributed between the 2 groups. Twenty-nine radiographs of small animal thorax were used. The procedure consisted in three experimenter-supervised phases: 1. training, 2. visual recognition test, 3. feature description test. In the training phase, each screen showed two radiographs with the name of the disease present in each. In the group 1 (pathology/normal condition), a radiograph of a patient and a normal image were shown next to each other. In the group 2 (pathology/pathology condition), two radiographs of patients with the same disease were shown next to each other. The 9 screens were presented twice, with the diseases in a different order for the first and second runs. A Mann-Whitney test was used to compare the success rates of groups of students. Results On visual recognition test, there was no statistical difference in visual diagnostic accuracy between groups. When students gave the wrong answer, they often diagnosed the item as another disease of similar distribution (diffuse or focal). Students who received the practical teaching and students of group 1 had a higher accuracy for normal thoracic radiographs. On feature description test, no significant effect of comparison learning was found, but focal diseases were better described than diffuse diseases with a significant difference between these. Discussion/Conclusions Results show that comparison with normal images did not help in recognizing or describing thoracic pathologies but helps to recognize normal images. [less ▲]

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See detailComputed tomography-guided injection of muscle-derived mesenchimal stem cells in the intervertebral disc of dogs affected by natural disc degeneration: clinical safety and intervertebral disc imaging assessment
Liotta, Annalisa Pia ULg; Sandersen, Charlotte ULg; Ceusters, Justine ULg et al

Poster (2016, September 01)

Introduction/Purpose: Pre-clinical randomized controlled animal trials have been conducted to evaluate the effects of mesenchymal stem cell (MSCs) transplantation on intervertebral disc (IVD) degeneration ... [more ▼]

Introduction/Purpose: Pre-clinical randomized controlled animal trials have been conducted to evaluate the effects of mesenchymal stem cell (MSCs) transplantation on intervertebral disc (IVD) degeneration. According to their histological results and to imaging assessment of the IVD, intradiscal injection of MSCs is effective, arresting or slowing IVDD process, and is associated with a low complication rate. Few of these studies have been conducted on canine artificially degenerated IVD, using bone marrow or adipose-derived MSCs. Therefore a systematic study on naturally degenerated IVD using MSCs obtained from autologous muscular tissue in dogs is still lacking. The aims of this study were to evaluate the clinical effects of intradiscal injection of muscle-derived MSCs and its effects on imaging features of the intervertebral disc. Methods: Eight experimental dogs were randomly included with the approval of the University’s Animal Care and Use Committee. The final inclusion criteria were the presence of naturally degenerated lumbosacral IVD detected on low-field magnetic resonance (MRI) images and the obtaining of 3 x 106 autologous muscle-derived MSCs. A computed tomography (CT) and MRI examination was performed before and 2 months after the procedure and 13 imaging parameters were assessed. Mesenchymal stem cells diluted in 0,2 ml of FRS Hypothermosol were injected in the lumbosacral IVD under CT-guidance. Clinical examinations were performed regularly during 1 month after the procedure. Results: Six dogs met the inclusion criteria. The remaining 2 dogs did not undergo intradiscal injections, but were used as control group. No major or minor complications were reported during the procedure. No abnormalities were noticed during the clinical examinations. No statistically significant variations of IVD imaging features were noticed before and after the injections. Discussion/Conclusions: Intradiscal injection of muscle-derived MSCs is clinically safe and it is not associated with any progression of the IVD degeneration, detected by CT or low-field MRI imaging. Further studies are needed to assess its efficacy as treatment for the canine natural IVD degeneration. [less ▲]

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See detailComputed tomographic findings of a far lateral lumbar disc extrusion in a dog
Rizza, Maïlis ULg; Bouvy, Bernard ULg; Shimizu, Naomi ULg et al

Poster (2016, September 01)

Introduction In human medicine, far lateral lumbar disc extrusion (FLLDE) represents 7 to 12% of all disc herniations and MRI is the method of choice for diagnosis. MRI findings of a FLLDE has been ... [more ▼]

Introduction In human medicine, far lateral lumbar disc extrusion (FLLDE) represents 7 to 12% of all disc herniations and MRI is the method of choice for diagnosis. MRI findings of a FLLDE has been reported in one dog and the aim of this case report is to describe computed tomographic (CT) findings of a FLLDE in a dog. Methods A six-year-old neutered female Beagle with a good general health status was presented with a month history of left hind limb pain with shivering of this limb. Clinical examination revealed a left hind proprioceptive deficit but no pain was elicited at palpation. Results A CT scan pre- and post- contrast studies of the lumbosacral spine and a myelographic-CT were performed. A 1.3x0.6x0.3 cm homogeneous hyperattenuating (+/- 350 HU) ovoid structure was observed at the left lateral aspect of L6-L7 intervertebral disc space. The L6-L7 intervertebral disc nucleus pulposus was calcified but the annulus fibrosus had a normal non-calcified attenuation and seemed intact apart from a very thin hyperattenuating line next to the ovoid structure. This change was well circumscribed by an even hyperattenuating rim (1000HU) mimicking a thin dense cortex and was in close proximity with the annulus fibrosus and the left transverse process of L7. Perineural fat was not observed and contrast enhancement was visualized at the level of the left sixth lumbar nerve root with impingement and thickening of this root. No compression of the spinal cord was observed at this level on the myeloCT. These findings were suggestive of a dystrophic mineralization or an osteochondromatosis. FLLDE was considered less likely because of the almost normal appearance of the annulus fibrosus. At surgery some mixed gelified calcified material consistent with disc material was removed at the level of the left L6-L7 nerve root tract and disc fenestration was performed. The histological analysis confirmed the presence of degenerated herniated vertebral disk. Discussion/Conclusions In human medicine, MRI and CT scan are the main diagnostic modalities employed for diagnosis of FLLDE. In veterinary medicine, CT is often used to assess spinal diseases because of its availability. To the authors’ knowledge, CT findings of a FLLDE have not been described previously in dogs. Moreover, the thin dense cortex appearance surrounding the disc material was surprising. In conclusion, FLLDE should be included in the differential diagnosis of a calcified ovoid structure lateral to the spine even if the annulus fibrosus appears normal and if this structure is in close relation with the vertebral transverse process. [less ▲]

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See detailVisuo-spatial STM impairment link to a serial order component deficit in children with Velocardiofacial syndrome
Attout, Lucie ULg; Vossius, Line ULg; Noël, Marie-Pascale et al

Poster (2016, September 01)

Some previous studies showed that verbal short-term memory (STM) is better preserved than visuospatial STM in the velocardiofacial syndrome (VCFS), a neurodevelopmental disorder resulting from a 22q11.2 ... [more ▼]

Some previous studies showed that verbal short-term memory (STM) is better preserved than visuospatial STM in the velocardiofacial syndrome (VCFS), a neurodevelopmental disorder resulting from a 22q11.2 deletion. This deficit is generally assigned to a more global visuospatial skills deficit. However, for verbal STM, previous study suggested a specific deficit in the serial order component, processing considered as independent of modalities. In this study we proposed to explore the serial order component in visuospatial STM by contrasting simultaneous vs. sequential presentation of stimuli to maintain in children with VCFS, in order to see in what extent the deficit is global and resulting from visuospatial deficit or whether this deficit is specific to the serial order component. We tested a group of 27 children and adolescents with VCFS to a control group, matched on verbal IQ performance estimated. The VCFS group showed impaired performance on the sequential configuration but similar performance on the simultaneous condition. These results support the idea of an amodal serial order component in STM. The implication of serial order STM deficits on numerical cognition will be discussed. [less ▲]

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See detailSIMULATION AND ANALYSIS OF RECEPTOR DYNAMICS IN A BMP REGULATORY NETWORK
Germain, Morgan ULg; Bolander, Johanna; Ji, Wei et al

Poster (2016, September)

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See detailIdentification of virulotypes and serotypes of enteropathogenic (EPEC) and Shigatoxigenic (STEC) Escherichia coli from healthy cattle at slaughterhouses in Wallonia.
Takaki, Shino; Duprez, Jean-Noël ULg; Fakih, Ibrahim et al

Poster (2016, September)

Escherichia coli producing the attachment-effacement (AE) lesion (EPEC) and/or Shiga toxins (STEC) cause enteritis and (bloody) diarrhoea in young calves and in humans, and are also present in the ... [more ▼]

Escherichia coli producing the attachment-effacement (AE) lesion (EPEC) and/or Shiga toxins (STEC) cause enteritis and (bloody) diarrhoea in young calves and in humans, and are also present in the intestines of healthy cattle. Besides the O157:H7 serotype, which is the main serotype causing STEC outbreaks in the world EPEC and STEC can belong to dozens of O serogroups. Of them, 9 have been frequently identified worldwide: O5, O26, O103, O104, O111, O118, O121, O145 and O165. The aim of this study is to identify the virulotypes and the O serotypes of EPEC and STEC isolated from healthy cattle at slaughterhouses in Wallonia. A total of 245 faeces (216 <1year-old bulls, 25 cows and 4 heifers) were sampled between April and June 2014 in 2 slaughterhouses in Wallonia and grown overnight at 37°C in Lauryl sulfate Enterobacteriaceae selective broth. The enrichment broths were assayed with an stx1, stx2 (Shiga toxin) and eae (AE lesion) triplex PCR and positive broths were inoculated onto 4 agar media: McConkey’s, Chromagar ES, Chromagar ES with tellurite and Chromagar STEC. Up to ten colonies per plate were picked up, sub-cultured and tested by the colony hybridization assay with gene probes targeting the stx1, stx2 and eae genes. The triplex PCR was again performed on all probe-positive isolates. The PCR-positive E. coli were subsequently assayed with two pentaplex PCR targeting the specific genes coding for the ten O serogroups listed above. Of the 2563 sub-cultured isolates, 744 isolates (29%) from 62 animals (25%) tested positive with the colony hybridization assay. Of them, 687 isolates (92%) from 59 animals were positive with the triplex PCR and the results of both tests were in agreement for 617 isolates (83%). One to 29 isolates per animal were probe- and PCR-positive. The positive isolates grew on Chromagar STEC (379; 55%), on Chromagar ES with tellurite (189; 28%), on Chromagar ES (62; 9%) or on McConkey’s agar (57; 8%). The most frequent virulotypes were eae+ (EPEC: 372 isolates; 54%), eae+stx1+ (AE_STEC: 119 isolates; 17%) and stx2+ (STEC: 118 isolates; 17%). In some animals different virulotypes were identified. The serogrouping with the two pentaplex PCR is in progress. AE-STEC, EPEC and STEC are excreted by 25% of the healthy cattle at slaughterhouses in Wallonia and different virulotypes can be excreted by the same animal. Conversely the methodology followed gives no precise idea of the actual level of excretion since the hybridization and PCR were performed after enrichment in selective broth. Therefore multiple isolates belonging to the same virulotype might represent the same clone. Identification of the serogroups and comparison by Pulsed Field Gel Electrophoresis should help to clarify that point. Quantitative (q)PCR is today the best method to quantify bacterial excretion, but is more expensive. The results of the hybridization and PCR correspond to between 80 and 90%. Though the colony hybridization is still useful for large-scale surveillance it needs radioactive probes for highest sensitivity and is more time-consuming than PCR. Therefore the PCR should be the first routine choice if it can be automatized at large scale. Further steps are the confirmation of the PCR results of the 70 isolates with different hybridization and PCR results and the identification of the serogroups with the two pentaplex PCR and later with PCR for the other serogroups, to compare them with isolates from young diarrhoeic calves and from humans. [less ▲]

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See detailIsolation of bacteriophages against Klebsiella pneumoniae and in vivo activity
Thiry, Damien ULg; Passet, Virginie; Dufour, Nicolas et al

Poster (2016, September)

Klebsiella pneumoniae is a bacterial pathogen able to induce severe healthcare-associated or community-acquired infections in humans and animals. The constant emergence of antibiotic resistant strains ... [more ▼]

Klebsiella pneumoniae is a bacterial pathogen able to induce severe healthcare-associated or community-acquired infections in humans and animals. The constant emergence of antibiotic resistant strains reinforces the need to find alternatives to antibiotic treatments. The use of bacteriophages is a promising approach. The aim of this study was to isolate bacteriophages directed against K. pneumoniae strains and to test their efficacy in a murine model. Bacteriophages against five different K. pneumoniae (2 of capsular type K1 and K2 and 1 undetermined) were isolated and purified from waste water collected in Paris area. The morphology of plaques (zones of bacterial killing) was recorded and several of them were purified three times by successive replating. Phage titers were determined by serial dilutions on their respective hosts as well as on 18 other Klebsiella strains to identify their host range. Kinetics of bacterial lysis were monitored during 15h at 3 multiplicities of infection, in triplicates. For in vivo experiment, a total of 10 mice were inoculated with 200 µl of K. pneumoniae (4.6E+07 CFU) by oral gavage and the level of K. pneumoniae in fecal samples was monitored for 10 days. Five mice did not receive any treatment and 5 other mice received a cocktail of three bacteriophages (8E+07 PFU) at day 4 post-inoculation. A total of 54 bacteriophages were isolated and purified with titers ranging from 2E+5 to 3.6E+10 PFU/ml. The host range study showed that bacteriophages against K. pneumoniae have a specificity related to the capsular type of their bacterial host. Lysis kinetics of bacteria suggested that different phages were isolated. Despite difficulties with the murine intestinal model, evidence was obtained that bacteriophages are able to reduce intestinal carriage. Our results show that bacteriophages isolated against K. pneumoniae are specific for a given capsular type, although further studies are necessary to provide more details on this capsular specificity and its molecular determinants. To fully address the in vivo potential of phages, a reliable mouse model of intestinal carriage of K. pneumoniae strains needs to be established. [less ▲]

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See detailSingle-Molecule Force Spectroscopy on Synthetic Helical Nanoarchitectures
Devaux, Floriane ULg; Li, Xuesong; Huc, Ivan et al

Poster (2016, September)

Inspired by the many folded conformations of the molecular machineries in nature, chemists have been developing the syntheses of artificial folded molecular architectures, namely foldamers. The ... [more ▼]

Inspired by the many folded conformations of the molecular machineries in nature, chemists have been developing the syntheses of artificial folded molecular architectures, namely foldamers. The investigation of these molecules using AFM-based Single Molecule Force Spectrosocopy (SMFS) allows the elucidation of both mechanochemical properties and conformational dynamics on the unimolecular scale in solution. The stepwise synthesis of aromatic oligoamide-based foldamers was designed to produce well-defined helically-folded molecular architectures. A PEO tether was coupled to one end of the foldamer. SMFS pulling experiments on this system yielded specific and reproducible force-extension patterns characteristic of single foldamers. Those patterns were further analyzed to determine unfolding forces and dynamics as well as to propose mechanistics hypotheses of the unfolding process. Several helical foldamers presenting variable lengths were considered. The force values measured for those foldamers are higher than those previously measured in natural biopolymers showing a high stability under a load and a propensity for the development of emergent properties. In addition, the increased stability of these aromatic oligoamide foldamers was confirmed by the observation of almost instantaneous reversibility of the unfolding under load. [less ▲]

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See detailRadioscopy laboratory diagnostic of epizootic diseases in Belgium and European countries
Cargnel, Mickaël ULg; Roelandt, Sophie; Van der Stede, Yves et al

Poster (2016, September)

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See detailTargeted mutagenesis of orphan GPCRs of the SREB family
Laschet, Céline ULg; Dupuis, Nadine ULg; Soni, Arvind ULg et al

Poster (2016, September)

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See detailChemical profiling of major components in natural waxes to elucidate their roles in liquid oil structuring
Diem Doan, Chi; Ming To, Chak; Lynen, Frederik et al

Poster (2016, September)

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See detailRefractive and diffractive contribution of linear chromatic aberration (LCA) on depth-of-focus with trifocal intraocular lenses (IOLs)
Loicq, Jerôme ULg; Gatinel, Damien

Poster (2016, September)

Purpose: To investigate the refractive and diffractive contribution of LCA on depth of focus extension of trifocal IOLs in polychromatic light conditions Setting: University of Liège, Belgium; Fondation ... [more ▼]

Purpose: To investigate the refractive and diffractive contribution of LCA on depth of focus extension of trifocal IOLs in polychromatic light conditions Setting: University of Liège, Belgium; Fondation Ophtalmologique A. de Rothschild, Paris Methods: The LCAs associated with the three focal points of hydrophobic and hydrophilic diffractive FineVision trifocal IOLs (PhysIOL SA, Liège, Belgium), were simulated in an Arizona eye model and experimentally measured on an optical bench at 480, 546 and 650 nm. The effect of Abbe number and aperture on different IOL materials was also evaluated. Based on wavelength–dependent MTF through-focus curves and PSF properties, polychromatic behavior of the trifocal IOLs was assessed under mesopic and photopic conditions. Results: LCA amplitude and sign were different for each of the trifocal IOL focal points. The diffractive LCA for near and intermediate was independent of IOL material (GFree versus hydrophilic acrylic, 26%), while far vision LCA appeared to be controlled by the material Abbe number. Under polychromatic conditions, the LCA contributed to depth of focus extension with different types of lens material, providing maximal visual acuity under white light conditions at all distances. Conclusions: Diffractive trifocal IOLs show chromatic aberrations with an increase in depth of focus under polychromatic light. This effect likely contributes to the extended range of vision. [less ▲]

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See detailFunctional properties of extracellular polysaccharides produced by Enterobacter A47 grown on agro-food industry by-products
Antunes, Silvia; Freitas, Filomena; Alves, Vitor et al

Poster (2016, September)

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See detailUse of NIR hyperspectral imaging to detect and quantify nodules on root system of associated crops
Eylenbosch, Damien ULg; Pierreux, Jérome ULg; Fernández Pierna, Juan Antonio et al

Poster (2016, September)

Winter wheat and peas cultivated in association and harvested when grains are dry show promising results in temperate areas. This association reach a good land equivalent ratio, reduce the nitrogen ... [more ▼]

Winter wheat and peas cultivated in association and harvested when grains are dry show promising results in temperate areas. This association reach a good land equivalent ratio, reduce the nitrogen fertilizer needs and obtain high quality harvest. These results are probably explained by the transfer of nitrogen from peas nodules to wheat roots. To test this hypothesis, quantification of nodules is required. Visual counting of nodules is time consuming and discrimination between the two kinds of roots is almost impossible. A new method is therefore needed. Near infrared hyperspectral imaging (NIR-HIS) was tested as a rapid method to quantify the amount of nodules and roots of each species in soil samples. [less ▲]

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See detailDomestic tools, hafting, and the evolution of technology: The Upper Palaeolithic of Hohle Fels as a case study
Taipale, Noora ULg; Conard, Nicholas J.; Rots, Veerle ULg

Poster (2016, September)

Innovations relevant to human evolution often involve subsistence technology, which can affect the success of individual groups, and Homo sapiens in general. However, Palaeolithic technologies include ... [more ▼]

Innovations relevant to human evolution often involve subsistence technology, which can affect the success of individual groups, and Homo sapiens in general. However, Palaeolithic technologies include more than just hunting tools, and a proper understanding of hunter-gatherer ways of living requires knowledge of the organisation of diverse tasks and activities, including the manufacture and maintenance of tools and other equipment. One central aspect of technological evolution is the development of tool hafting [1, 2], which is not only restricted to hunting and gathering implements, but also affects so-called domestic tool categories. We present the results of an on-going project that focuses on hafting and use of stone tools in the Upper Palaeolithic through detailed functional analysis of selected assemblages from European key sites (Hohle Fels, Abri Pataud, Maisières-Canal), which have yielded rich lithic and organic assemblages from secure chronological contexts. Here the focus is on classic Upper Palaeolithic tool categories, such as endscrapers and burins, from the Gravettian and Magdalenian levels of the cave site Hohle Fels (Germany) [3, 4]. We suggest that domestic tools can offer a valuable source material, since for most of them, hafting is not a necessity as it is for spear and arrow tips. An increase in hafting implies an increase in time investment, which has implications for task organisation and specialisation. The Hohle Fels assemblage offers an interesting case study for temporal changes (or continuity) in the frequency and techniques of tool hafting. The projectile technology shows a clear shift from the Gravettian to the Magadalenian, marked by the introduction of a microlithic technology (backed bladelets). For other tool categories, the changes seem more subtle. Our goal is to characterise the tools used in manufacture and maintenance tasks, and to evaluate whether the Gravettian to Magdalenian transition witnesses changes in tool design and use that go beyond hunting equipment. The observed differences between tool classes and time periods are explained with a reference to details of tool use, such as the rate of edge wear development and stone tool exhaustion, as well as shifts in treatment of organic raw materials. The results suggest that domestic tools can aid in understanding long-term technological evolution, and create a baseline against which we can (re)assess the role of shifts observed in technologies that are more susceptible to morphological change, such as projectiles. References: [1] Rots, V., 2013. Insights into early Middle Palaeolithic tool use and hafting in Western Europe: The functional analysis of level IIa of the early Middle Palaeolithic site of Biache-Saint-Vaast (France). J. Archaeol. Sci. 40, 497–506. [2] Barham, L., 2013. From Hand to Handle: The First Industrial Revolution. Oxford University Press, Oxford. [3] Conard, N. J., Bolus, M., 2003. Radiocarbon dating the appearance of modern humans and timing of cultural innovations in Europe: New results and new challenges. J. Hum. Evol. 44, 331–371. [4] Taller, A., Bolus, M., Conard, N. J., 2014. The Magdalenian of Hohle Fels Cave and the Resettlement of the Swabian Jura after the LGM. In: Otte, M., Le Brun-Ricalens, F. (Eds.), Modes de contacts et de déplacements au Paléolithique eurasiatique: Actes du Colloque international de la commission 8 (Paléolithique supérieur) de l'UISPP, Université de Liège, 28–31 mai 2012. Centre National de Recherche Archéologique, Luxembourg. [less ▲]

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See detailA new method for identifying experimental and Palaeolithic hafting adhesives using GC×GC-HRTOFMS
Cnuts, Dries ULg; Perrault, Katelynn ULg; Dubois, Lena ULg et al

Poster (2016, September)

Hafting adhesives can be seen as an indication of the cognitive and technical capabilities of the manufacturers and therefore play a key role in the debate on human evolution [1], [2]. These adhesives are ... [more ▼]

Hafting adhesives can be seen as an indication of the cognitive and technical capabilities of the manufacturers and therefore play a key role in the debate on human evolution [1], [2]. These adhesives are mainly from plant origin (resins, gums or tar) and are often mixed with beeswax and other additives in order to make them less brittle. Archaeological evidence indicates that these adhesives were already in use in the Paleolithic from at least 120.000 years ago [3]. Discoveries for this period are however very rare and only become abundant from the Neolithic onwards [4]. Their longer exposure to biochemical alteration processes limits the chance of survival in the archaeological record. If they are present on Paleolithic stone tools, they appear often in such small quantities that they are challenging to identify by traditional gas chromatography – mass spectrometry (GC-MS) or even to remove them effectively from the stone tool. The destructive nature of traditional GC-MS analysis can damage these rare samples for other analyses. Our study aims to overcome this problem by using headspace solid phase microextraction (HS-SPME) for sample extraction and analysis by comprehensive two-dimensional gas chromatography –high-resolution time-of-flight mass spectrometry (GC×GC-HRTOFMS), which has the benefit of analyzing the volatile organic compound (VOC)s from the substance and it does not destroy the complete matrix of the adhesive. We present the results of a pilot study intended to examine the potential of this technique for analyzing Palaeolithic adhesives. The study involved (1) an examination of experimental compound adhesives (containing pine and spruce resin, acacia gum and birch tar; beeswax and additives like charcoal, flax or ochre), (2) a blind test on experimental samples to test the reliability of the method and to determine the minimal quantity necessary for analysis, and (3) the analysis of different Palaeolithic adhesives and of experimental samples of at least 15 years old. The analysis was done on extracted and non-extracted adhesives. A unique chromatographic fingerprint was obtained for all experimental adhesive samples. The VOC profile of these adhesives proved to be extremely complex and therefore benefitted significantly from multidimensional separation techniques. GC×GC-HRTOFMS provided an optimal chromatographic separation of adhesive components. HRTOFMS data was used in order to obtain high-resolution mass spectral data to contribute to compound identification. Our study demonstrates that GC×GC-HRTOFMS is a well suited method for identifying small quantities of compound adhesives with significant potential for Palaeolithic contexts. The additional sensitivity afforded by this technique in comparison to traditional GC-MS is a substantial benefit for these quantities. Furthermore, by only analyzing the VOCs of the adhesives, these rare archeological samples are not destroyed and can still be used for other types of analysis. [1] L. Wadley, ‘Compound-Adhesive Manufacture as a Behavioral Proxy for Complex Cognition in the Middle Stone Age’, Curr. Anthropol., vol. 51, no. s1, pp. S111–S119, Jun. 2010. [2] L. Barham, From Hand to Handle: The First Industrial Revolution. Oxford: Oxford University Press, 2013. [3] P. P. A. Mazza, F. Martini, B. Sala, M. Magi, M. P. Colombini, G. Giachi, F. Landucci, C. Lemorini, F. Modugno, and E. Ribechini, ‘A new Palaeolithic discovery: tar-hafted stone tools in a European Mid-Pleistocene bone-bearing bed’, J. Archaeol. Sci., vol. 33, no. 9, pp. 1310–1318, Sep. 2006. [4] M. Regert, ‘Investigating the history of prehistoric glues by gas chromatography-mass spectrometry.’, J. Sep. Sci., vol. 27, no. 3, pp. 244–54, Feb. 2004. [less ▲]

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See detailPlant esterified oxylipins: structure – function relationship
Genva, Manon ULg; Andersson, Mats X.; Nasir, Mehmet Nail ULg et al

Poster (2016, September)

In the present work, high quantities of arabidopsides were extracted and purified from Arabidopsis thaliana L.

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See detailHow reliable are the models to study recent climate change ? A study of heat/cold waves and radiative fluxes trends over 1900-2010 using the model MAR in Belgium
Wyard, Coraline ULg; Fettweis, Xavier ULg; Scholzen, Chloé ULg

Poster (2016, August 29)

This research aims to assess the ability of the regional climate model MAR ("Modèle Atmosphérique Régional") to reconstruct the observed twentieth century climatology of extreme events and solar radiation ... [more ▼]

This research aims to assess the ability of the regional climate model MAR ("Modèle Atmosphérique Régional") to reconstruct the observed twentieth century climatology of extreme events and solar radiation in Belgium, as a necessary condition for reliable future projections. Simulations were performed by forcing MAR with several reanalyses: the ERA40/ERA-Interim, the ERA-20C and the NCEP/NCAR-v1. The results suggests that increasing air temperature would have generated decreasing relative humidity which would have lead to a decrease in cloudiness and an increase in solar downward radiation. This research illustrates the dependency between RCMs and their forcings. The forcing reanalyses can generate divergent trends while contrary to Global Climate Models (GCM), the reanalyses assimilate observations and are supposed to represent the same climate. [less ▲]

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See detailThe influence of background noise on vocal loading parameters in music theory teachers
Schiller, Isabel ULg; Morsomme, Dominique ULg; Sfez, Lou et al

Poster (2016, August 23)

Background: Music theory teachers, who teach rhythm, singing and other music-related skills and topics, depend greatly on a well-functioning voice. Unlike other schoolteachers, who primarily use their ... [more ▼]

Background: Music theory teachers, who teach rhythm, singing and other music-related skills and topics, depend greatly on a well-functioning voice. Unlike other schoolteachers, who primarily use their voice as a pedagogic tool, music theory teachers also use it as an instrument. Furthermore, they often engage in vocally demanding free-time activities requiring a singing voice. To date, few studies have specifically looked at the voice use of music theory teachers. This study aims (1) to measure the background noise level and the amount of vocal loading affecting this specific population, and (2) to describe the influence of background noise on vocal loading parameters. Methods: Thirteen French-speaking music theory teachers (9 females and 4 males) working in a music school were monitored for one workweek, using the VoxLog voice dosimeter (Sonvox). To investigate the professional and extra-professional environments, all subjects wore the dosimeter from early morning until the end of the day. The parameters analysed were background noise level, duration of phonation, sound pressure level (SPL) and fundamental frequency (F0) of voice. Results: Overall, the mean background noise level was 75.2 dB (SD=5.4). We measured higher background noise level at work (mean=78.2 dB, SD=5.8) than in the extra-professional environment (mean=72.2 dB, SD=5.2). As expected, a rise in background noise was accompanied by a significant rise in voice SPL in both males and females (r=.61, p<.001). A significant correlation between background noise and F0 was found in females (r=.41, p=.002), but not in males (r=.39, p=.055). Furthermore, our data exhibit a significant correlation between background noise and duration of phonation (r=.05, p<.001). Conclusion: Our data suggest, that in class, music theory teachers must cope with background noise levels that dramatically exceed the limit of 35 dB recommended by the WHO (Inserm, 2006). High background noise levels lead to an increase in voice SPL, a phenomenon known as the Lombard effect (Inserm, 2006). In female subjects, we also observed a rise in F0 further to high background noise. Like Ternström, Södersten, and Bohman’s (2002) study, our data indicate that high background noise levels increase the duration of phonation. In a noisy environment, subjects seem to prolong the voiced segments of speech to make themselves understood. In other words, high background noise levels result in higher vocal loading. In the long run, this may increase the risk of voice disorders such as hyperfunctional dysphonia or vocal fold pathologies consecutive to repeated microtrauma in music theory teachers. [less ▲]

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See detailOverhanging Constraints in Addivitive Manufacturing Using Two Different Tools
Bauduin, Simon ULg; Collet, Maxime ULg; Duysinx, Pierre ULg

Poster (2016, August 23)

Topology optimization is widely used as a design tool for advanced application in mechanical, aerospace and automotive industries. This technique offers an optimal distribution of a predetermined amount ... [more ▼]

Topology optimization is widely used as a design tool for advanced application in mechanical, aerospace and automotive industries. This technique offers an optimal distribution of a predetermined amount of material in a given design space. In the last years, a lot of efforts has been invested into the development of high performance methods such as homogenization, SIMP or BESO. However as the state of the art in manufacturing experiences evolution, a coupling between topology optimization and additive manufacturing is needed. Additive manufacturing has numerous advantages that fits the characteristics of topology optimized designs. It can manufacture highly complex design without high cost increase and furthermore continuous density material of the SIMP method could be manufactured by lattice structures. With all the opportunities given by the additive manufacturing the urge to bind the last one to topology optimization is heavily required. Specific constraints related to manufacturing issues have to be taken into account such as the need of supports structures to ensure a good heat evacuation during the manufacturing process, as well as to hold up overhanging section. Some researches have been done to try to include this constraint in the optimization problem such as Leary and al or Andrew T. Gaynor. However this work focuses on 2 different methods (projection scheme and mechanical approach) to tackle the overhanging problem and compare them . [less ▲]

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See detailA Comparison between four Techniques to Measure Cardiac Output
Pironet, Antoine ULg; Dauby, Pierre ULg; Chase, J. Geoffrey et al

Poster (2016, August 17)

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See detailCASTLE4D : The castle of Franchimont
Luczfalvy Jancsó, Andrea ULg; Hoffsummer, Patrick ULg; Billen, Roland ULg et al

Poster (2016, August 16)

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See detailTechniques et Méthodes nucléaires : Application de la Spectrométrie Gamma au Cameroun
Moyo N., Maurice; Kayo, Steve; Ngelem M., Eric J. et al

Poster (2016, August 04)

L’imaginaire populaire est de plus en plus pessimiste au sujet du mot nucléaire, utilisées selon eux, uniquement pour détruire, en cas de guerre. Une idée reçue, mais presque imposée par l'attitude des ... [more ▼]

L’imaginaire populaire est de plus en plus pessimiste au sujet du mot nucléaire, utilisées selon eux, uniquement pour détruire, en cas de guerre. Une idée reçue, mais presque imposée par l'attitude des pays développés qui donnent l'impression de recourir au nucléaire, le plus souvent, à des fins militaires. Pourtant, les applications du nucléaire sont utiles dans des domaines aussi variés que l'agriculture, la médecine, la détection des fuites dans les barrages, la surveillance de la qualité de l'air, des eaux, des sols, des matériaux de construction, des denrées alimentaires etc. Au Cameroun, l'utilisation des rayonnements ionisants (énergie nucléaire) est en pleine croissance. Ce, spécifiquement dans les domaines médical et industriel. La radioprotection est de plus en plus l’objet des recherches et des mesures au Cameroun. Des techniques d’analyse nucléaires sont également utilisées pour déterminer les risques radiologiques lies aux rayonnements naturels provenant de l’environnement. Dans ce cadre, l’unité de recherche « Physique Fondamentale » de l’université de Douala en collaboration avec l’ANRP (Agence Nationale de RadioProtection) utilise la spectrométrie gamma pour quantifier et qualifier l’exposition des camerounais aux rayonnements. Deux mémoires de master ont à cette occasion révéler le niveau d’exposition due aux rayonnements provenant du sol de l’Université de Douala d’une part et d’autre part l’exposition due aux matériaux de construction dans la ville de Douala. Les études sur les matériaux de construction (ciment utilisé dans la ville de Douala) ont permis d’observer que l’activité spécifique dans les échantillons de ciment varie d’un radionucléide à l’autre. L’estimation des paramètres radiologiques comme (l’activité du radium équivalent Raeq, l’indice du risque externe (Hex) et interne (Hin), le taux de dose absorbée dans l’air et la dose effective annuelle (AEDE) ont montré que l’utilisation comme matériaux de construction du ciment analysé était sans risque particulier. [less ▲]

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See detailParcours migratoire et résilience : ressources et contraintes perçues par des réfugiés syriens et afghans
Vereshchagin, Anton ULg; Glowacz, Fabienne ULg

Poster (2016, August)

Les chiffres du Haut-Commissariat des Nations Unies pour les réfugiés indiquent une augmentation considérable du flux migratoire en Europe depuis 2010. Cette tendance s’explique notamment par une violence ... [more ▼]

Les chiffres du Haut-Commissariat des Nations Unies pour les réfugiés indiquent une augmentation considérable du flux migratoire en Europe depuis 2010. Cette tendance s’explique notamment par une violence persistante dans des pays tel que l’Afghanistan et l’évolution du conflit en Syrie. Dans le cadre d’une approche écosystémique, les contraintes perçues et rappelées par les sujets ayant « survécu » à la « traversée » migratoire et aux micro-traumatismes associés ont été mises en perspectives avec, les motivations liées à cette migration et les ressources perçues par les migrants. Notre étude de type exploratoire se base sur la rencontre avec 15 sujets âgés de 21 à 67 ans : 7 afghans et 8 syriens (13 hommes et 2 femmes) résidant dans des structures d'accueil pour demandeurs d'asile et hors structure, en Belgique. Des entretiens semi-structurés ont été menés en anglais et en russe et trois questionnaires ont été administrés : le locus de contrôle (1966), le sentiment d'auto-éfficacité (1997) et le soutien social perçu (1985). L'analyse des discours a mis en évidence différents types de motivations à la migration ne prédéterminant pas nécessairement la complexité du voyage qui apparait davantage dépendante des contextes situationnels, des opportunités et diverses contraintes. Par contre, les motivations semblent associées aux ressources perçues. Sur base de l’analyse du récit de la trajectoire, ainsi que des questionnaires, plusieurs facteurs de protection et de résilience ont été identifiés. Nous avons également proposé une nouvelle adaptation du modèle transthéorique de changement (DiClemente et Prochaska, 1982) au processus migratoire. [less ▲]

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See detailL’Hadrianus de Montserrat (P.Monts.Roca III, inv.162 → - 165 ↓) : une source nouvelle sur la Colonia Claudia Ara Agrippinensium ?
Berg, Tatiana ULg

Poster (2016, August)

Sixième partie du codex miscellaneus de Montserrat (P.Monts.Roca III, inv.162 → - 165 ↓ = MP3 2998.11 = LDAB 552, papyrus, 2e moitié IVe siècle), qui présente la particularité de contenir des textes à la ... [more ▼]

Sixième partie du codex miscellaneus de Montserrat (P.Monts.Roca III, inv.162 → - 165 ↓ = MP3 2998.11 = LDAB 552, papyrus, 2e moitié IVe siècle), qui présente la particularité de contenir des textes à la fois grecs et latins, profanes et chrétiens, tous écrits par la même main, le récit latin en prose Hadrianus relate notamment le passage de l’empereur Hadrien dans la ville de Cologne, dont il évoque des realia. Après les avoir répertoriées et avoir évalué leur authenticité, le poster met en évidence l’apport du texte à la connaissance de la Colonia Claudia Ara Agrippinensium et de son autel des Ubiens. [less ▲]

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See detailProofing & Reduction Strategies Used by Emergency Residents to Manage Fatigue-related Risk
Berastegui, Pierre ULg; Ghuysen, Alexandre ULg; Nyssen, Anne-Sophie ULg

Poster (2016, July 29)

Fatigue and sleep loss are typically associated with psychomotor and cognitive impairment resulting in poorer task performance. Most of these studies are conducted in controlled settings and involve the ... [more ▼]

Fatigue and sleep loss are typically associated with psychomotor and cognitive impairment resulting in poorer task performance. Most of these studies are conducted in controlled settings and involve the completion of experimental tasks. Only a few field studies involving exhausted residents have been conducted over the past decade, and they yielded to contradictory results (Ellman et al., 2004). One of the key factors that could be involved in the non-linear relationship between fatigue and performance in specific work context reside in the mobilization of Fatigue Proofing Strategies. FPS are adaptive and protective risk-reduction behaviors that improve the resilience of a system of work (Dawson et al., 2012). In this study, we aimed to identify and classify proofing strategies mobilized by EMS residents using an inductive content analysis approach. EMS residents reported a range of strategies for reducing subjective level of sleepiness (reduction strategies, n=15) or managing its consequences (proofing strategies, n=17). Content analysis yielded to three sub-categories of proofing strategies: Behavioral Compensation (n=8), Error’s Opportunity Reduction (n=5) and Error’s Consequences Mitigation (n=4). Our results show that EMS residents use both types of strategies although none of the proofing strategies were part of their training program. Despite the current informal use, there is significant potential for implementation of more formal processes. [less ▲]

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See detailBiofilm fermentation for the production of insect pathogenic fungi
Bawin, Thomas ULg; Francis, Frédéric ULg; Delvigne, Frank ULg

Poster (2016, July 27)

Currently, integrated pest management that aims to reduce the use of synthetic insecticides by considering all appropriate alternative methods, is promoted. In that context, insect pathogenic fungi could ... [more ▼]

Currently, integrated pest management that aims to reduce the use of synthetic insecticides by considering all appropriate alternative methods, is promoted. In that context, insect pathogenic fungi could be developed as biopesticides in two ways: spores but also metabolites that are recognized as virulence factors. Targeting adequate fermentation method is an important requirement to obtain fungal products (i.e. spores, enzymes and metabolites) of biotechnological interest. The 'Microbial Processes and Interactions' laboratory has developed an innovative fermentation technology (referred to as ‘biofilm fermentation’) involving the growth of fungal biomass on inert supports that are immersed in a liquid nutrient medium. Confining fungal biomass on immersed inert structures provides a hybrid production system aiming to keep a solid-state physiology for sporulation and secretion of metabolites while controlling fermentation parameters. This research project proposes to transfer this technology to culture insect pathogenic fungi, such as Metarhizium anisopliae, for the production of spores and insecticidal metabolites. Development stages include the qualitative and quantitative characterization of its impact on insecticidal products as well as scale-up to industrial level. [less ▲]

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See detailAharonov-Bohm oscillations of bosonic matter-wave beams in the presence of disorder and interaction
Chrétien, Renaud ULg; Dujardin, Julien; Petitjean, Cyril ULg et al

Poster (2016, July 27)

We study the one-dimensional (1D) transport properties of an ultracold gas of Bose-Einstein condensed atoms through Aharonov-Bohm (AB) rings. Our system consists of a Bose-Einstein condensate (BEC) that ... [more ▼]

We study the one-dimensional (1D) transport properties of an ultracold gas of Bose-Einstein condensed atoms through Aharonov-Bohm (AB) rings. Our system consists of a Bose-Einstein condensate (BEC) that is outcoupled from a magnetic trap into a 1D waveguide which is made of two semi-infinite leads that join a ring geometry exposed to a synthetic magnetic flux φ. We specifically investigate the effects both of a disorder potential and of a small atom-atom contact interaction strength on the AB oscillations. The main numerical tools that we use for this purpose are a mean-field Gross-Pitaevskii (GP) description and the truncated Wigner (tW) method. We find that a correlated disorder suppress the AB oscillations leaving thereby place to Aronov-Al’tshuler-Spivak (AAS) oscillations. The competition between disorder and interaction leads to a peak inversion at Φ = π, that is a signature of a coherent backscattering (CBS) peak inversion. This is confirmed by truncated Wigner simulations. [less ▲]

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See detailQuantitative characterization and calibration of salt water intrusion models with electrical resistivity tomography
Beaujean, Jean; Hermans, Thomas ULg; Vandenbohede, Alexander et al

Poster (2016, July 26)

Groundwater quality and coastal ecosystems in coastal areas are among the most vulnerable as they are threatened by excessive groundwater withdrawals, sea level rise and storm events potentially leading ... [more ▼]

Groundwater quality and coastal ecosystems in coastal areas are among the most vulnerable as they are threatened by excessive groundwater withdrawals, sea level rise and storm events potentially leading to salt water intrusions or infiltration into fresh water aquifers. The environmental protection and sustainable management of these groundwater resources often involves the development and calibration of a groundwater model subsequently used to forecast the total dissolved solid content (TDS). However, groundwater models are often built based on a limited number of sparse data due to borehole availability. Geophysical methods can provide spatially and temporally distributed data for hydrogeological modeling at relatively limited costs. In particular, electrical resistivity tomography (ERT) is very sensitive to the conductivity of pore water which is directly linked to the TDS content. The method is therefore well-suited for the monitoring of salt water intrusions. However, the inversion of ERT data involves a regularization process so that the resulting tomogram is only an estimate of the true resistivity distribution, suffering from smoothing and varying resolution. In many cases, the interpretation of ERT remains qualitative and skewed. In this contribution, we propose two different methods to improve the information content that can be extracted from ERT data. First, we show with a field example from Belgium how alternative regularization methods can be developed to integrate independent information into the inversion process of ERT. This enabled us to obtain a resistivity distribution much closer to the one observed in validation boreholes. Then, a site-specific petrophysical relationship is used to derive the TDS content of the aquifer from ERT tomograms. This can be directly used as input in the calibration process of a hydrogeological model. We also show how it is possible to counterbalance the effect of resolution loss with depth for surface ERT by filtering the results relative to their sensitivity. We show that this filtering is mandatory to use the ERT-derived information for calibrating a hydrogeological model. In a second example, we show how a fully coupled inversion approach can be used to directly invert geophysical data together with hydrogeological data for the calibration of hydrogeological models. At each iteration of the calibration, the simulated TDS content is transformed in a resistivity distribution using a parameterized petrophysical relationship and forward geophysical modeling yields the geophysical response. We show that this approach enables to better estimate the hydrogeological parameters of the simulated coastal aquifer than with an uncoupled approach if the conceptual model is sufficiently representative. With those two examples, we demonstrate the usefulness of ERT in the monitoring of salt water intrusions, both qualitatively to identify most vulnerable zones and quantitatively to estimate ERT-derived TDS contents or geophysical data and calibrate hydrogeological models. An innovative approach may consist in a conjunctive use of filtered geophysically-derived and geophysical data within the coupled hydrogeophysical inversion framework. Such an uncoupled-coupled approach based on a resolution threshold approach may offer a promising developing trend in hydrogeophysical inversion. [less ▲]

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See detailImpacts of entomopathogenic fungi on biology and behaviour of the invasive Brown Marmorated Stink Bug (Hemiptera, Pentatomidae)
Fingu Mabola, Junior Corneille ULg; Serteyn, Laurent ULg; Bawin, Thomas ULg et al

Poster (2016, July 25)

Halyomorpha halys St˚al (Hemiptera, Pentatomidae) is an invasive stink bug coming from Eastern Asia. Besides causing important yields losses in orchards, crop and vegetable fields, it overwinters inside ... [more ▼]

Halyomorpha halys St˚al (Hemiptera, Pentatomidae) is an invasive stink bug coming from Eastern Asia. Besides causing important yields losses in orchards, crop and vegetable fields, it overwinters inside houses as agglomerates of dozens. In Europe, this Brown Marmorated Stink Bug (BMSB) was accidentally introduced in Switzerland in 2007 and has been later observed in surrounding countries (France, Italy, Germany). Based on the current US situation, we can reasonably fear that BMSB will have colonized most of Europe countries in less than a decade. If we already discern a few fungus strains that are efficient against BMSB, very little is known about their actual impact on the insect itself. So we investigated the in- fluence of a fungal infection on insect development parameters and behaviour. Olfactometry was settled to investigate the dispersion and aggregation trends, while electropenetography was used to assess the feeding behaviour. Our results will be discussed to present changes according to healthy/fungus-infected status, in relation to potential biological control for that pest. [less ▲]

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See detailThe verbal overshadowing effect in children and adults is unrelated to the specific content of descriptions
Vanootighem, Valentine ULg; Brédart, Serge ULg; Dehon, Hedwige ULg

Poster (2016, July 21)

Verbal descriptions of unfamiliar faces have been found to impair later identification of these faces in children and adults, a phenomenon known as the “verbal overshadowing effect” (VOE, Schooler and ... [more ▼]

Verbal descriptions of unfamiliar faces have been found to impair later identification of these faces in children and adults, a phenomenon known as the “verbal overshadowing effect” (VOE, Schooler and Engstler-Schooler, 1990). The present study thoroughly examined the person descriptive abilities of 7–8, 10–11, and 13–14-year-old children and adults and their influence on later identification performance. Our aim was to specifically assess the prediction of the “content” account suggesting that a verbal overshadowing arises because participants generate an inadequate verbal description and later rely upon it during retrieval. Results showed a verbal overshadowing effect in all age groups but neither accuracy, length nor content of descriptions were found to be associated with identification accuracy. [less ▲]

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See detailNeural correlates of memory for internal thoughts versus external stimuli experienced in natural settings
Stawarczyk, David ULg; Jeunehomme, Olivier ULg; D'Argembeau, Arnaud ULg

Poster (2016, July 19)

To investigate the brain regions supporting the remembrance of internal thoughts versus external events, we asked participants to perform a short walk while wearing a lifelogging device that continuously ... [more ▼]

To investigate the brain regions supporting the remembrance of internal thoughts versus external events, we asked participants to perform a short walk while wearing a lifelogging device that continuously and automatically took pictures. In a subsequent fMRI session, they were shown brief sequences of pictures from their walk and were asked to remember either external events or internal thoughts that they experienced while walking. Results showed that remembering internal thoughts activated the medial prefrontal cortex and temporal poles to a greater extent than remembering external events, whereas remembering external events was associated with higher activation in lateral frontoparietal regions. These findings suggest that memory for internal thoughts involves the reactivation of brain regions supporting the initial formation of these thoughts. [less ▲]

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See detailRecollection versus familiarity in normal aging and in mild cognitive impairment: Impact of test format.
Simon, Jessica ULg; Gilsoul, Jessica ULg; SALMON, Eric ULg et al

Poster (2016, July 18)

The aim of this study was to investigate the impact of test format on recollection and familiarity in normal aging and in MCI. Seventy young participants, 65 younger-old, 53 older-old, and 13 MCIs were ... [more ▼]

The aim of this study was to investigate the impact of test format on recollection and familiarity in normal aging and in MCI. Seventy young participants, 65 younger-old, 53 older-old, and 13 MCIs were presented with forced-choice and yes/no visual recognition memory tasks with the Remember/Know/Guess paradigm. The young people had better recognition performance than younger-old, who performed better than older-old and MCIs. Recollection and familiarity declined progressively in healthy aging. In MCI, recollection was more affected than familiarity, but patients demonstrated a more liberal use of familiarity. Finally, test format did not influence strongly the results. Young people used recollection more often in the forced-choice task compared to the yes/no task. [less ▲]

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See detailMetagenetics and predictive microbiology: a new tool to understand the kinetics of microbial subpopulation in minced pork meat
Cauchie, Emilie ULg; Delhalle, Laurent; Taminiau, Bernard et al

Poster (2016, July 18)

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See detailMetagenetics and predictive microbiology: a new tool to understand the kinetics of microbial subpopulations in Belgian white pudding
Cauchie, Emilie ULg; Gand, Mathieu; Kergourlay, Gilles et al

Poster (2016, July 18)

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See detailGamma-Ray Spectrometry: Experimental Measurement and Monte Carlo Simulation using GEANT4 toolkit
Guembou Shouop, Cébastien Joel ULg; Ndontchueng Moyo, Maurice; Chene, Grégoire ULg et al

Poster (2016, July 13)

Nowadays the precision in the measurement has become a challenge for physicists. That is why in recent decades, the interest is very granted to simulation. Since 1940, the method Monte Carlo is more ... [more ▼]

Nowadays the precision in the measurement has become a challenge for physicists. That is why in recent decades, the interest is very granted to simulation. Since 1940, the method Monte Carlo is more useful for validation and even for prediction of the results of the experiment. The aim of this study is to validate experimental models. Our laboratories are equipped with HPGe gamma spectrometers for measuring the natural radioactivity, it becomes interesting to compare and even to improve the performance of our system. Geant4 is used for the construction of the geometry of detection, the physics processes and the primary particles. First and prliminary result was prsented in this paper. [less ▲]

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See detailCounting time measurement and statistics in gamma spectrometry: the balance
Guembou Shouop, Cébastien Joel ULg; Ndontchueng Moyo, Maurice; Chene, Grégoire ULg et al

Poster (2016, July 11)

Nuclear counting statistics at high count rate are assessed on a γ-ray spectrometer set-up. Our typical gamma spectrometry system consists of a High Purity Germanium (HPGe) detector, liquid nitrogen ... [more ▼]

Nuclear counting statistics at high count rate are assessed on a γ-ray spectrometer set-up. Our typical gamma spectrometry system consists of a High Purity Germanium (HPGe) detector, liquid nitrogen cooling system, preamplifier, detector bias supply, linear amplifier, analog-to-digital converter (ADC), multichannel storage of the spectrum, and data readout devices. Although the system is powerful enough for background measurements, it is important, nowadays, to have a great statistical in short time measurement: which is a challenge for scientists. The purpose of this study was to determine the average time for gamma spectrometry measurement. To detect Uranium, Thorium and their respective daughters and Potassium series with a relative related error less than 1%, it was found that it is necessary to count during a minimum of 24 Hours (86,400 s). This result is in accordance to the literature with planar geometry detector. These results conduct us to make the following three guidelines for selecting the detector best suited for an application: 1. The more detector material available (germanium semi-conductor), the higher the full-energy peak efficiency. 2. The smaller the distance between the detector and the source material, the higher the full- energy peak efficiency. 3. While better resolution gives a better MDA, the resolution contributes only as the square root to the MDA value, whereas the MDA is proportional to the full-energy peak efficiency. This idea came to us by comparing the spectra of measuring radioactivity lasts for 12 hours in the day that does not fully covered the night spectra for the same sample. The conclusion after several investigations became clearer: to remove all effects of radiation from outside (earth, sun and universe) our system, it is necessary to measure the background for 24, 48 or 72 hours. In the same way, the samples have to be measures for 24, 48 or 72 hours to be safe to be purified the measurement (equality of day and night measurement). It is also possible to not use the background of the winter in summer. Depend to the energy of radionuclide we seek, it is clear that the most important steps of a gamma spectrometry measurement are the preparation of the sample and the calibration of the detector. [less ▲]

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See detailIntegrated microfluidic device for in line SERS detection for glyphosate and related metabolites
Emonds-Alt, Gauthier ULg; Malherbe, Cédric ULg; Monbaliu, Jean-Christophe ULg et al

Poster (2016, July 07)

The goal of this work is to develop a quantitative analytical method for the glyphosate and its major metabolite the aminomethylphosphonic acid (AMPA) by coupling microfluidics with surface enhanced Raman ... [more ▼]

The goal of this work is to develop a quantitative analytical method for the glyphosate and its major metabolite the aminomethylphosphonic acid (AMPA) by coupling microfluidics with surface enhanced Raman spectroscopy (SERS). This work is divided into 4 axes : (a) bimetallic nanoparticles synthesis in a microreactor, (b) nanoparticles functionnalisation, (c) SERS quantification of glyphosate/AMPA and (d) miniature prototype development composed of axes a to c. The first section aims at the synthesis of bimetallic nanoparticles (Au-Ag, Au-Cu and Ag-Cu) in a microfluidic device. This microfluidic device integrates a first section for the synthesis of monometallic nanoparticles (core) and a second section for the reductive deposition of a second metal (shell). The second axe of this work deals with the functionnalisation of nanoparticles to improve the selectivity of this method for the selected analytes. Two types of functionnalisation are studied : PEGylation (a) with multi-arm PEG ending with -SH and/or (b) with linear heterobifunctionnal PEG. The third axe consists in measuring quantitatively glyphosate and AMPA in different matrices, such as water, urine and fruit juice. Finally, the forth axe deals with the development of a portable detection system to perform on-site analysis. This prototype integrates the microfluidic device for nanoparticles synthesis, their functionnalisation, an injection port followed by a mixing section for the sample and an integrated Raman spectrometer for in-line analysis. [less ▲]

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See detailNovel butanol pretreatment significantly improves delignification and saccharification of different lignocellulosic biomasses
Schmetz, Quentin ULg; Teramura, Hiroshi; Jacquet, Nicolas ULg et al

Poster (2016, July 07)

Organosolv pretreatment using diluted acid and butanol allows the separation of cellulose, hemicelluloses and lignin into three distinct phases. The butanol process has been investigated on six different ... [more ▼]

Organosolv pretreatment using diluted acid and butanol allows the separation of cellulose, hemicelluloses and lignin into three distinct phases. The butanol process has been investigated on six different biomasses: tall fescue, sugarbeet pulp, sugarcane bagasse, beech wood, eucalyptus and Japanese cedar. Dilute acid pretreatment has been performed under similar conditions for comparison. [less ▲]

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See detailNonlinear analysis of compliant mechanisms: application to tape springs
Dewalque, Florence ULg; Bruls, Olivier ULg

Poster (2016, July 07)

Brief summary of the mechanical behaviour of tape springs. Main results obtained by the means of finite element models. Description of the experimental set-up and results. See the extended abstract for ... [more ▼]

Brief summary of the mechanical behaviour of tape springs. Main results obtained by the means of finite element models. Description of the experimental set-up and results. See the extended abstract for more details. [less ▲]

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See detailRestricted interests in autism with versus without speech onset delay : the importance of perceptually versus thematically organized interests
Chiodo, Liliane ULg; Majerus, Steve ULg; Eusèbe, Sandrine et al

Poster (2016, July 07)

Objectives : To explore whether autistic adults with vs without speech delay also differ in the perceptual vs thematic nature of their restricted interests.

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See detailDevelopment and optimization of a TD-GC/MS methodology for detection and quantifi cation of furan released in air using of an experimental design.
Alsafra, Zouheir ULg; Scholl, Georges ULg; Romain et al

Poster (2016, July 07)

In the aim of understanding the way in which human is exposed to furan present in the air of an occupational area, an analytical method of Thermal desorption-gas chromatography/Mass spectrometry (TD-GC/MS ... [more ▼]

In the aim of understanding the way in which human is exposed to furan present in the air of an occupational area, an analytical method of Thermal desorption-gas chromatography/Mass spectrometry (TD-GC/MS) has been developed and optimized using a Plackett–Burman experimental design. This method was then used to study the phenomena of diffusion of furan released in air from a contamination source. This source of furan is simply a coffee machine located in a closed controlled room. Results show that furan concentration increases quickly over time after turning on the coffee machine until reaching a maxima. Then it starts to decrease slowly. On the other hand, concentration of furan seems to be identical everywhere in the conditioned room in each moment. [less ▲]

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See detailOptimisation de la production d’acide furan-2,5-dicarboxylique à partir de déchets verts pour la conception de plastiques bio-basés
Istasse, Thibaut ULg; Jacquet, Nicolas ULg; Richel, Aurore ULg

Poster (2016, July 06)

Afin de trouver des alternatives renouvelables aux produits issus de l’industrie pétrochimique, de nombreuses voies de recherches ont été explorées. Une voie prometteuse est la technologie des dérivés ... [more ▼]

Afin de trouver des alternatives renouvelables aux produits issus de l’industrie pétrochimique, de nombreuses voies de recherches ont été explorées. Une voie prometteuse est la technologie des dérivés furaniques. Parmi ces composés, le 5-hydroxyméthylfurfural (5-HMF) fait partie des molécules plateformes les plus importantes1. Il s’agit d’un produit de dégradation obtenu par déshydratation des hexoses2,3. Le 5-HMF peut servir de base à la conception de nombreuses molécules valorisables comme l’acide furan-2,5-dicarboxylique dont la structure proche de l’acide téréphtalique permet des applications dans la conception de polymères bio-basés3. L’acide furan-2,5-dicarboxylique respecte la législation REACH selon l’European Chemicals Agency4. Un rapport de l’EFSA de 2014 a démontré que cette substance ne posait pas de problème de toxicité lors de son utilisation comme monomère de base dans les plastiques d’emballage pour aliments5. Selon la société Avantium, le FDCA peut être utilisé pour produire un plastique entièrement bio-basé, le polyéthylène furanoate (PEF), qui affiche des performances supérieures à celle du poléthylène téréphtalate (PET) en termes de stabilité thermique, de propriétés mécaniques et de perméabilité aux gaz6. Si le FDCA peut être convertit en de nombreux produits à haute valeur ajoutée, il existe toutefois un frein majeur à son exploitation industrielle : son précurseur, le 5-HMF, n’est pas encore produit en grande quantité1. Ce problème est dû principalement à la déshydratation non sélective des sucres de la biomasse qui aboutit à de nombreux autres produits que le 5-HMF. La première difficulté à surmonter est donc la mise au point d’un procédé permettant de déshydrater de manière efficace et sélective les sucres de la biomasse. Le 5-HMF est également peu stable en milieu acide où il se décompose en acide formique et en acide lévulinique2. L'enjeu du projet de recherche présenté est donc l’optimisation de la production de 5-HMF à partir d’un ou plusieurs types de biomasses dans un premier temps, puis l’optimisation de la conversion du 5-HMF produit en FDCA. Les paramètres à prendre en compte sont notamment les sources de biomasse, l’efficacité des prétraitements concernant l’extraction des sucres, la sélectivité et l’efficacité de la conversion de ces sucres en 5-HMF (système mono- ou biphasique), l’étude de divers catalyseurs, le coût des traitements, etc… [less ▲]

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See detailEtude de la composition chimique de Pseudotsuga menziesii (Mirb.) Franco et évaluation de l’impact de divers prétraitements lignocellulosiques sur l’extraction de la lignine
Berchem, Thomas ULg; Schmetz, Quentin ULg; Jacquet, Nicolas ULg et al

Poster (2016, July 06)

La raréfaction des ressources fossiles est une certitude à l’heure actuelle. Il est donc primordial de trouver des voies de production plus durables pour des produits de consommation courante. Le ... [more ▼]

La raréfaction des ressources fossiles est une certitude à l’heure actuelle. Il est donc primordial de trouver des voies de production plus durables pour des produits de consommation courante. Le bioraffinage fait partie des solutions envisagées pour substituer les matériaux originaires de la filière pétrochimique. Dans cette optique, ce travail se focalise sur l’extraction et la caractérisation de la lignine à partir d’une biomasse présente en abondance en région Wallonne, Pseudotsuga menziesii (Mirb.) Franco (Douglas). Ce travail vise à montrer l’impact de divers prétraitements lignocellulosiques, tant en terme de rendements et de pureté d’extraction qu’au niveau de la modification de la structure et des propriétés des lignines. Ces différents paramètres sont évalués par des techniques gravimétriques (Klason), chromatographiques (chromatographie d’exclusion stérique) et spectroscopiques (RMN 2D HSQC). Pseudotsuga menziesii (Mirb.) Franco a été préalablement caractérisé par son taux de matière lignocellulosique (cellulose, hémicelluloses, lignine), ainsi que sa teneurs en cendres, en protéines et en extractibles (à l’eau et à l’éthanol). Les lignines natives ont été caractérisées par RMN 2D HSQC. [less ▲]

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See detailIdentifying wheat varieties with low acrylamide potential
Lecart, Brieuc ULg; Jacquet, Nicolas ULg; Anseeuw, Laurent et al

Poster (2016, July 05)

Maillard reactions are responsible for the formation of many compounds in food that have been baked at temperatures above 120°C1. Some of these compounds are sought for their contribution to the ... [more ▼]

Maillard reactions are responsible for the formation of many compounds in food that have been baked at temperatures above 120°C1. Some of these compounds are sought for their contribution to the organoleptic qualities of food but others, such as acrylamide, have been identified since 1986 as reprotoxic, genotoxic and carcinogenic in animals2. Synthesized from a chain reaction between free sugars and free asparagine, acrylamide has been found in many food such as products prepared from wheat flour1,3,4. The correlation between the amount of free sugars and free asparagine in raw food with the acrylamide content in the baked food has been well documented5. For this reason we compared the levels of 15 wheat varieties and identified wheat varieties with significantly lower level (=0.05) in acrylamide precursors. Those varieties could therefore be used preferentially in products intended for food. [less ▲]

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See detailL’intégration d’indicateurs biologiques dans un réseau de surveillance des sols afin d’améliorer le diagnostic de la qualité du sol – une étude de cas dans le sud de la Belgique (Wallonie)
Krüger, Inken ULg; Chartin, Caroline; van Wesemael, Bas et al

Poster (2016, July 05)

Les organismes du sol et leurs activités sont essentiels pour le fonctionnement de l’écosystème du sol et ils peuvent donc servir comme indicateurs de la qualité du sol. Des efforts ont récemment été ... [more ▼]

Les organismes du sol et leurs activités sont essentiels pour le fonctionnement de l’écosystème du sol et ils peuvent donc servir comme indicateurs de la qualité du sol. Des efforts ont récemment été menés pour intégrer les indicateurs biologiques de la qualité du sol dans les réseaux de surveillance régionaux/nationaux. Le but de cette étude était de déterminer des gammes de valeurs pour six indicateurs biologiques et deux quotients éco-physiologiques pour les sols agricoles. La respiration potentielle, la biomasse microbienne (carbone et azote), la minéralisation nette de l’azote, la diversité métabolique des bactéries du sol, l’abondance des vers de terre, le quotient microbien et le quotient métabolique ont été mesurés dans 60 sites dans des régions agricoles contrastées (différents types de sol et climat) et différentes utilisations de sol (prairies et cultures) sélectionnés d’un réseau de surveillance du carbone organique du sol (CARBOSOL). Les liens entre indicateurs biologiques et paramètres chimiques (le pH du sol, carbone organique total, soluble, labile et stable) sont analysés. Quatre des six indicateurs biologiques sélectionnés (respiration potentielle, biomasse microbienne (carbone et azote) et diversité métabolique des bactéries du sol) sont significativement plus élevés sous prairies que sous cultures. Les gammes de valeurs sont plus larges sous prairies que sous cultures. Les indicateurs biologiques sélectionnés ne sont pas significativement influencés par la région agricole. Les meilleures corrélations avec les paramètres chimiques ont été trouvées pour la respiration potentielle et la biomasse microbienne (carbone et azote). L’étude définit des gammes de valeurs pour les sols agricoles à l’échelle régionale (Wallonie) séparées par utilisation de sol (prairies et cultures) et présente une base solide pour l’établissement d’un réseau de surveillance de la qualité biologique du sol. [less ▲]

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See detailHigh-temperature and quantitative XRD study of typical Westerwald clays (Germany)
Fontaine, François ULg; Fagel, Nathalie ULg

Poster (2016, July 05)

The Westerwald is one of the largest and oldest clay mining area of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of Devonian ... [more ▼]

The Westerwald is one of the largest and oldest clay mining area of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of Devonian rocks. During the Miocene, intense volcanic activities led to a large basalt cover, protecting the clays from the erosion. The fine fraction is mainly composed of kaolinite and illite, with the possible presence of interstratified I S. Other minerals such as quartz, feldspars, hematite, goethite or anatase are present in variable concentrations. Four typical Westerwald clays were chosen for this study: kaolinite-rich clay, kaolinite-illite clay, a red and a yellow firing clays. The first goal is to perform quantitative XRD using two different methods and to compare them: reference intensity ratio (RIR) and Rietveld (using Topas and BGMN). The second goal is the study of those samples using high-temperature XRD (HTXRD). The samples were heated up to 1250°C and a XRD pattern was obtained in situ every 100°C. The results show the temperatures of vitrification and formation of mullite and cristobalite varying from one sample to another, which is mainly linked to their flux concentration. [less ▲]

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See detailPIXE-PIGE analysis of Early Medieval Glass Artefacts at IPNAS cyclotron external beam line
Chene, Grégoire ULg; Van Wersch, Line ULg; Biron, Isabelle et al

Poster (2016, July 05)

Detailed reference viewed: 10 (0 ULg)
See detailProgramme de soutien aux aidants de patients présentant la maladie d’Alzheimer : une étude de cas
Clesse, Audrey ULg; Missotten, Pierre ULg; Adam, Stéphane ULg

Poster (2016, July 05)

Il est largement reconnu que vivre au jour le jour avec un proche atteint de la maladie d’Alzheimer est une situation particulièrement éprouvante. La charge générée par cette maladie peut menée à des ... [more ▼]

Il est largement reconnu que vivre au jour le jour avec un proche atteint de la maladie d’Alzheimer est une situation particulièrement éprouvante. La charge générée par cette maladie peut menée à des états de fatigue psychologiques et physiques, voir au burnout, pour l’aidant. Plusieurs études sur la santé des aidants prenant en charge un proche dément ont montré qu’ils constituent, en comparaison aux personnes s’occupant d’un individu âgé non dément, une population à risque, notamment en termes de symptômes dépressifs, détresse psychologique ou de problèmes de santé. Ces constats alarmants justifient la mise en place de programmes de soutien visant à offrir un suivi thérapeutique aux personnes ayant un conjoint ou un parent présentant une démence de type Alzheimer. Nous présentons l’étude de cas de Mme C.G., fille d’une patiente âgée de 79 ans, ayant suivi le programme de soutien développé par Adam et al. (2009), basé sur l’approche de gestion du stress qui suggère l’utilisation de stratégies d’ajustement centrées sur la résolution de problèmes. Avant et après l’intervention, Mme C.G. a répondu à différents questionnaires examinant sa santé psychologique (MBI, BDI-II, STAI, etc.), sa manière de gérer la maladie de son parent (WCC, CAMI, SCQ, etc.) et l’état général de la patiente (ADRQL, IADL, NPI). La comparaison pré et post-intervention apporte des éléments positifs, notamment concernant l’amélioration de la qualité de vie de l’aidante, de son sentiment de compétence et d’efficacité à gérer la maladie au quotidien. Concernant le burnout, qui était la priorité de cette intervention, nous constatons que l’épuisement émotionnel de l’aidante tend à diminuer au cours des séances de counseling. Un autre constat particulièrement important concerne les changements familiaux opérés tout au long de la thérapie ; ce qui pose question quant à la réorganisation de la dynamique familiale. Ces résultats positifs démontrent l’importance de développer des programmes d’aide aux aidants grâce à une approche clinique globale et holistique de la situation, étant donné les composantes neuropsychologiques, cognitives et systémiques impliquées. [less ▲]

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See detailGirls and Math Careers Expectations: Influence of Teacher Support and Motivational Variables
Jaegers, Doriane ULg; Lafontaine, Dominique ULg

Poster (2016, July)

Drawing on the expectancy-value theory, the three basic dimensions of instructional quality and the self-determination theory, this study examines the relation between teacher support, motivational ... [more ▼]

Drawing on the expectancy-value theory, the three basic dimensions of instructional quality and the self-determination theory, this study examines the relation between teacher support, motivational variables, course enrollment and career expectations in the domain of math. Gender differences are also investigated. Teacher support is seen as the fulfilment of the need of relatedness which is defined by the affective and academic quality of the teacher-student relationship. [less ▲]

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See detailDroplet manipulation on fiber networks
Weyer, Floriane ULg; Pan, Zhao; Truscott, Tadd et al

Poster (2016, July)

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See detailStudy of Mezoneuron benthamianum, a plant traditionally used against malaria in Guinea
Tchinda Tiabou, Alembert ULg; Loua, Jean; Esters, Virginie ULg et al

Poster (2016, July)

Despite some improvements in malaria control, this parasitic disease remains a major public health problem in many African countries, causing about 400 000 deaths/year through the continent, mainly by ... [more ▼]

Despite some improvements in malaria control, this parasitic disease remains a major public health problem in many African countries, causing about 400 000 deaths/year through the continent, mainly by children under the age of five (WHO, 2015). In Guinea, the leaves of Mezoneuron benthamianum Baill. are traditionally used to treat malaria (Traore et al., 2013) and showed a good antiplasmodial activity in an antiprotozoal in vitro screening (Traore et al., 2014), as well as promising results in a preliminary small-scale ethnomedical study (unpublished data), encouraging us to continue the study of this plant. The aim of this work was to evaluate the activity of M. benthamianum leaves extracts against P. falciparum using an in vitro test model (p-LDH assay) and to undertake a bio-guided fractionation to identify the compounds responsible for the activity. Hydroethanolic extracts (70% v/v) of M. benthamianum leaves showed a moderate in vitro activity against P. falciparum 3D7, with IC50 = 22.5 – 32.6 µg/ml, depending on the batch; while a dark precipitate formed during ethanol evaporation showed higher activity (IC50 = 6,5µg/ml). The bioguided fractionation was performed on this most active fraction and allowed the isolation of three diterpens, two flavonoids, resveratrol, gallic acid and its ethylester, β-sitosterol glucoside and pheophorbide derivatives. The active compounds belong to several phytochemical classes, including flavonoids, pheophorbide and gallic acid derivatives, contributing together to the global antiplasmodial activity of the hydroalcoholic extract against P. falciparum parasite. This study gives some concrete evidence to support the ethnopharmacological use of Mezoneuron benthamianum leaves extract in the management of malaria. The active compounds can be further studied for their antiplasmodial potential, as well as their suitability to be used as quality markers for the standardization of this herbal drug from the Guinean traditional pharmacopeia. [less ▲]

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See detailMagnetocapillary self-assemblies: Swimming and micromanipulation
Grosjean, Galien ULg; Hubert, Maxime ULg; Lagubeau, Guillaume et al

Poster (2016, July)

Floating magnetic particles can self-assemble into structures, by a combination of a magnetic dipole-dipole interaction and an attraction due to the interfacial deformation. These structures are ... [more ▼]

Floating magnetic particles can self-assemble into structures, by a combination of a magnetic dipole-dipole interaction and an attraction due to the interfacial deformation. These structures are periodically deformed in a non reciprocal way using magnetic fields, which leads to controllable low Reynolds number locomotion. Such microswimmers provide a basis for micromanipulation applications such as transport of micro-objects, local mixing of fluids or surface cleaning. [less ▲]

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See detailCoherent backscattering in the Fock space of Bose- and Fermi-Hubbard systems
Engl, Thomas; Dujardin, Julien; Tisserond, Emilie et al

Poster (2016, July)

Coherent backscattering generally refers to a significant and robust enhancement of the average backscattering probability of a wave within a disordered medium, which from a semiclassical point of view ... [more ▼]

Coherent backscattering generally refers to a significant and robust enhancement of the average backscattering probability of a wave within a disordered medium, which from a semiclassical point of view arises due to the constructive interference between backscattered trajectories and their time-reversed counterparts. We recently investigated the manifestation of this wave interference phenomenon in the Fock space of a disordered Bose-Hubbard system of finite extent [1], which can potentially be realized using ultracold bosonic atoms within optical lattices. Preparing the atoms in a well-defined Fock state of the lattice and letting the system evolve for a finite time will, for suitable parameters of the system and upon some disorder average over random on-site energies of the lattice, generally give rise to an equidistribution of the occupation probability within the energy shell of the Fock space that corresponds to the initial energy of the system, in accordance with the quantum microcanonical ensemble. We find, however, that the initial state is twice as often encountered as other Fock states with comparable total energy, which is a consequence of coherent backscattering [1]. Most recently, we showed that this phenomenon also arises in spin 1/2 Fermi-Hubbard rings that involve Rashba hopping terms (which combine inter-site hoppings with spin flips and arise from spin-orbit coupling), for which a newly developed semiclassical theory [2] correctly predicts a coherent enhancement of the occupation probabilities of the initial state and its spin-flipped counterpart. Moreover, performing a global spin flip within this Fermi-Hubbard system will give rise to significant spin echo peaks on those two Fock states, which is again a consequence of quantum many-body interference [3]. The semiclassical predictions of these enhancements and peaks are found to be in very good agreement with numerical findings obtained from the exact quantum time evolution within this Fermi-Hubbard system. [1] T. Engl, J. Dujardin, A. Argüelles, P. Schlagheck, K. Richter, and J. D. Urbina, Phys. Rev. Lett. 112, 140403 (2014). [2] T. Engl, P. Plößl, J. D. Urbina, and K. Richter, Theoretical Chemistry Accounts 133, 1563 (2014). [3] T. Engl, J. D. Urbina, and K. Richter, arXiv:1409.5684. [less ▲]

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See detailHeavy methane to explain the unexplained recent methane growth ?
Bader, Whitney ULg; Strong, Kim; Walker, Kaley

Poster (2016, July)

Methane (CH4) is the second most important greenhouse gas emitted by human activities in the Earth’s atmosphere. Although it is roughly 200 times less abundant than carbon dioxide, it is a 28 times more ... [more ▼]

Methane (CH4) is the second most important greenhouse gas emitted by human activities in the Earth’s atmosphere. Although it is roughly 200 times less abundant than carbon dioxide, it is a 28 times more potent greenhouse gas. Approximately one fifth of the changes in the Earth’s balance energy caused by human-linked greenhouse gases since the beginning of industrialization (~1750) is due to methane. Methane is emitted by both natural sources and human activities. Indeed, methane can be emitted to the atmosphere through coal mining, oil and gas exploitation, rice cultures, domestic ruminant animals, biomass burning, waste management, wetlands, termites, methane hydrates and ocean. In the atmosphere, methane is mainly destroyed by the radical hydroxyl, also called the detergent of the atmosphere, and therefore plays a major role on the oxidizing capacity of the atmosphere. Since the beginning of the industrialization, atmospheric methane concentrations have increased by 260% to reach 1824 pbb in 2013. From the 1980s until the beginning of the 1990s, atmospheric methane was significantly on the rise, then stabilized during 1999-2006 to rise again afterwards. To this day, the source or sink responsible of this latter increase remains unexplained. Through each emission process, heavy molecules of methane (with one additional neutron either on a carbon or on one hydrogen atom) are emitted along methane (12CH4). The main heavy molecules of methane, called isotopologues (13CH4 and CH3D), are respectively ~110 and ~60 000 times less abundant than methane. Despite their small abundances, they give crucial information on the concentration of methane in the atmosphere and its evolution. Indeed, both isotopologues are emitted with specific emission ratio depending on the emission sources. Determining isotopic ratio of atmospheric methane is therefore a unique tracer of its budget. While the non-monotonous trend of methane is subject of an extensive number of studies, to our knowledge, no study of the isotopic ratio of methane derived from ground-based solar observations has been published to date. Measurements of heavy methane from Fourier Transform InfraRed spectra recorded with state of the art spectrometers installed at Eureka [Arctic, Canada] and Toronto [Ontario, Canada] along with analysis of observations collected by a portable instrument [Portable Atmospheric Research Interferometric Spectrometer for the Infrared, PARIS-IR], installed at Eureka will help fill this gap. Indeed, the produced time series, compared with the corresponding satellite observations (ACE-FTS) products will ease data interpretation and contribute to a global view of the question of isotopologues. [less ▲]

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See detailPassive flutter suppression using a nonlinear tuned vibration absorber
Verstraelen, Edouard ULg; Gourc, Etienne ULg; Kerschen, Gaëtan ULg et al

Poster (2016, July)

A recent study showed that the addition of a linear tuned vibration absorber could increase the flutter speed of a rigid wing with pitch and flap degrees of freedom by about 35%. However, the absorber was ... [more ▼]

A recent study showed that the addition of a linear tuned vibration absorber could increase the flutter speed of a rigid wing with pitch and flap degrees of freedom by about 35%. However, the absorber was turning the initial super-critical bifurcation into a sub-critical one. This work shows numerically that adding a nonlinear restoring force to the absorber can restore the su- percritical behaviour of the bifurcation and further reduce the post-instability limit cycle amplitude. [less ▲]

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