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See detailIs the Mehler reaction the main photoprotective mechanism occurring in Symbiodinium in hospite?
Roberty, Stéphane ULg; Beraud, Eric; Ferrier-Pagès, Christine et al

Poster (2015, August)

The ecological success of reef-building corals throughout tropical oligotrophic waters relies on the symbiosis between cnidarians and photosynthetic dinoflagellates of the genus Symbiodinium. This ... [more ▼]

The ecological success of reef-building corals throughout tropical oligotrophic waters relies on the symbiosis between cnidarians and photosynthetic dinoflagellates of the genus Symbiodinium. This association allows the transfer of highly energetic compounds and an efficient recycling of growth-limiting nutrients. In the natural environment the holobiont have to cope with significant daily variations in light intensities that sometimes exceed Symbiodinium photosynthetic capacity. Fortunately, these organisms possess regulatory features that help to ensure that high light intensities can be endured without the accumulation of photodamage. Among them, it has been found recently that photoreduction of oxygen downstream PSI by the so-called Mehler reaction was the main alternative electron sink at the onset and steady state of photosynthesis in different cultured strains of Symbiodinium. In this study, we investigated the occurrence and the relative amplitude of this photoprotective mechanism in Symbiodinium cells living within the tropical coral Stylophora pistillata and the sea anemone Anemonia viridis. To this end, joint measurements of oxygen evolution, PSI and PSII activities were conducted. The impacts of CO2 limitation and CO2 fixation on the photoreduction of oxygen by PSI was also studied by using several inhibitors targeting the carbon concentrating mechanism and the Calvin-Benson-Bassham cycle. Conversely to cultured cells, these measurements revealed that the Symbiodinium located in S. pistillata, under control conditions, rely on other photoprotective mechanisms than the Mehler reaction to prevent over-excitation of the photosynthetic apparatus. However, we observed an increased O2 uptake capacity during photosynthesis when the efficiency of the carbon fixation was reduced in S. pistillata. [less ▲]

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See detailReduced Order Modeling Techniques in Experimental Dynamic Substructuring
Roettgen, Dan; Dossogne, Tilàn ULg; Seeger, Benjamin et al

Poster (2015, August)

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See detailThe hidden face of the human macrophage chitotriosidase: taking a new look at this enzyme based on the biochemical and phylogenomic analysis of its chitin binding domain
Crasson, Oscar ULg; Legrand, François; Léonard, Raphaël et al

Poster (2015, August)

Carbohydrates recognition is a critical process involved in numerous aspects of the cell biology such as inflammation, innate immune responses and proliferation. Chitin is an homopolysaccharide composed ... [more ▼]

Carbohydrates recognition is a critical process involved in numerous aspects of the cell biology such as inflammation, innate immune responses and proliferation. Chitin is an homopolysaccharide composed of β-1,4-linked N-acetylglucosamine (GlcNAc) units that is an abundant structural component of various infectious organisms like protozoans, nematodes and fungi. As there is no endogenous chitin produced by mammals, this polymer appeared to be a strategic target for innate immune agents which is why various carbohydrate binding proteins, associated or not with catalytic domains, are synthetized by plants and animals and are known to play a crucial role in innate immunity. The macrophage chitotriosidase (HCHT) is one of the three active chitinases synthetized by humans and has triggered significant attention recently due to its association with various inflammatory disorders. HCHT belongs to the Glycosyl Hydrolase family 18 (GH18) and is known to be involved in innate immunity. Nevertheless, its precise physiological function remains unclear. As numerous GHs, HCHT is a modular protein composed of a catalytic domain (GH18) associated to a Carbohydrate Binding Module (CBM) which is essential to hydrolyse crystalline chitin. If the catalytic domain GH18 is highly common in other GHs from animals, plants, fungi, bacteria, archea and viruses, its CBM (named ChBD) is much less conserved which makes the association between these two domains particularly intriguing. This work aims to demystify HCHT’s physiological function. Firstly, using competitive inhibition assays, we have highlighted the ability of ChBD to interact with chitooligosaccharides (GlcNAc1-2-4-6) which suggests that ChBD can potentially act as a lectin domain. Secondly, to better understand the molecular basis for chitin recognition, we have used homology modelling to build, with high confidence, the 3D structure model of ChBD. Based on this model, a specific set of residues has been selected for alanine scan mutagenesis which has allowed us to define the minimum chitin binding interface of the protein. Thirdly, Phylogenomic studies were performed to analyse the evolutionary history of the isolated catalytic and ChBD domains and understand how these domains were combined. Based on all these results, we discuss a new way of looking at HCHT where its ChBD would be the key determinant that has guided the catalytic domain from a basic metabolic function to a critical component of innate immunity in human. Finally, we propose a mechanism that explains how this enzyme could act at the molecular level to defend us against chitin-containing pathogens. [less ▲]

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See detailEffects of Music and Language Expertise on the Implicit Learning of Musical and Linguistic Structures?
Larrouy, Pauline ULg; DeChristen, Eleonore; Kolinsky, Régine

Poster (2015, August)

1. Background The cognitive consequences of music and language expertise are rarely compared. Recently, we observed different profiles in music and language experts in implicit learning of linguistic ... [more ▼]

1. Background The cognitive consequences of music and language expertise are rarely compared. Recently, we observed different profiles in music and language experts in implicit learning of linguistic structures of sung material (Larrouy-Maestri, Leybaert, & Kolinsky, 2013), with music experts performing better. Yet, as the language experts were speech therapists, this could reflect their formal, late language training. 2. Aims We aimed at comparing informal vs. formal language training and at examining the effect of dual expertise (in music and language) on the implicit statistical learning of musical and linguistic structures. We therefore used the sung material of Larrouy-Maestri et al. (2013) and tested the ability of music and/or language experts as well as of dual experts to implicitly learn the linguistic and/or musical structure of this material. 3. Method 14 music experts, 14 bi- or multi-linguals and 8 dual experts (bi- or multi-linguals also experts in music) were asked to listen attentively to 7.30 min of a continuous stream made out of 6 trisyllabic nonsense “words” sung on 6 three-tone melodies. Each “word” (defined by transitional probabilities) carried its specific melody, as melodic and linguistic transitional probabilities were congruent. A two-alternative forced-choice required choosing between “words” and “partwords”, either spoken (in the linguistic test) or instrumental (in the music test) was used to test participants’ learning of the linguistic or melodic structure. 4. Results Expertise modulated performance in the linguistic test when including the speech-therapists of our previous study (F(3, 49) = 5.92, p = .002, η2 = 0.28), who performed the worst. In the musical test, there was no significant group effect (p = .25), but one-sample t-tests showed that only the dual experts performed above chance, with 62.5% correct (p < .01). 5. Conclusions Whereas informal language training and music expertise lead to similar abilities to implicitly learn linguistic - but not musical - structure, this was not the case of formal language expertise. The combination of music and informal language expertise led to a particular profile, i.e., to the ability to learn simultaneously the musical and linguistic structures of sung material. [less ▲]

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See detailModelling of the Nonlinear End-Systolic Pressure-Volume Relation and Volume-at-Zero-Pressure in Porcine Experiments
Davidson, Shaun M.; Kannangara, D. Oliver; Pretty, Christopher G. et al

Poster (2015, August)

The End-Systolic Pressure-Volume Relation (ESPVR) is generally modelled as a linear relationship between P and V as cardiac reflexes, such as the baroreflex, are typically suppressed in experiments ... [more ▼]

The End-Systolic Pressure-Volume Relation (ESPVR) is generally modelled as a linear relationship between P and V as cardiac reflexes, such as the baroreflex, are typically suppressed in experiments. However, ESPVR has been observed to behave in a curvilinear fashion when cardiac reflexes are not supressed, suggesting the curvilinear function may be more clinically appropriate. Data was gathered from 41 vena cava occlusion manoeuvres performed experimentally at a variety of PEEPs across 6 porcine specimens, and ESPVR determined for each pig. An exponential model of ESPVR was found to provide a higher correlation coefficient than a linear model in 6 out of 7 cases, and a lower Akaike Information Criterion (AIC) value in all cases. Further, the exponential ESPVR provided positive V0 values in a physiological range in6 out of 7 cases analysed, while the linear ESPVR produced positive V0 values in only 3 out of 7 cases, suggesting linear extrapolation of ESPVR to determine V0 may be flawed. [less ▲]

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See detailSensory quality of beef patties inoculated with strains of Carnobacterium maltaromaticum with potential as biopreservatives
Didimo Imazaki, Pedro Henrique ULg; Jacques-Houssa, Charlotte ULg; Kergourlay, Gilles ULg et al

Poster (2015, August)

Biopreservation is the use of naturally occurring microorganisms and/or their inherent antimicrobial compounds to extend shelf life and to enhance the safety of foods. The aim of the present study was to ... [more ▼]

Biopreservation is the use of naturally occurring microorganisms and/or their inherent antimicrobial compounds to extend shelf life and to enhance the safety of foods. The aim of the present study was to perform a sensory evaluation of beef patties inoculated with strains of C. maltaromaticum with potential as biopreservatives. Three different strains of C. maltaromaticum (CM_824, CM_827 and CM_829) isolated from vacuum packaged beef with long shelf life were selected for this study. An untrained panel was requested to make a sensory evaluation of raw and cooked beef patties 8 and 10 days after inoculation with the selected strains at 104 and 106 UFC/g and storage in high O2 atmosphere. This preliminary study permitted to evaluate the effect of three C. maltaromaticum strains on the sensory quality of beef patties. Strain CM_827 did practically not change the sensory attributes of beef patties. Samples inoculated with strain CM_824 and CM_829 received the worst scores for several of the tested descriptors. Therefore, further research on the biopreservative capacity of C. maltaromaticum should be conducted with strain CM_827. [less ▲]

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See detailThe Hydroxyl Nightglow Emissions on Earth, Venus and Mars
Soret, Lauriane ULg; Gérard, Jean-Claude ULg; Piccioni, G. et al

Poster (2015, August)

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See detailStroke Volume Estimation using Aortic Pressure Measurements and Aortic Cross Sectional Area
Kamoi, Shun; Pretty, Christopher G.; Chiew, Yeong Shiong et al

Poster (2015, August)

Accurate Stroke Volume (SV) monitoring is essential for patient with cardiovascular dysfunction patients. However, direct SV measurements are not clinically feasible due to the highly invasive nature of ... [more ▼]

Accurate Stroke Volume (SV) monitoring is essential for patient with cardiovascular dysfunction patients. However, direct SV measurements are not clinically feasible due to the highly invasive nature of measurement devices. Current devices for indirect monitoring of SV are shown to be inaccurate during sudden hemodynamic changes. This paper presents a novel SV estimation using readily available aortic pressure measurements and aortic cross sectional area, using data from a porcine experiment where medical interventions such as fluid replacement, dobutamine infusions, and recruitment maneuvers induced SV changes in a pig with circulatory shock. Measurement of left ventricular volume, proximal aortic pressure, and descending aortic pressure waveforms were made simultaneously during the experiment. From measured data, proximal aortic pressure was separated into reservoir and excess pressures. Beat-to-beat aortic characteristic impedance values were calculated using both aortic pressure measurements and an estimate of the aortic cross sectional area. SV was estimated using the calculated aortic characteristic impedance and excess component of the proximal aorta. The median difference between directly measured SV and estimated SV was -1.4ml with 95% limit of agreement +/- 6.6ml. This method demonstrates that SV can be accurately captured beat-to-beat during sudden changes in hemodynamic state. This novel SV estimation could enable improved cardiac and circulatory treatment in the critical care environment by titrating treatment to the effect on SV. [less ▲]

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See detailDo Triclosan affect hearing development of Cyprinodon variegatus larvae?
Schnitzler, Joseph ULg; Benichou, Farida; Pinte, Nicolas et al

Poster (2015, August)

The aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS) has been shown to affect the thyroid system of teleost. Larval stages are ... [more ▼]

The aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS) has been shown to affect the thyroid system of teleost. Larval stages are particularly vulnerable to deleterious effects of endocrine disrupters because of potential impairment of fish development and behaviour. Thyroid hormones are critical to the development of the brain and auditory system. Thus, TCS could affect the development of the brain and hearing. The aims of this study were: to investigate hearing development in sheepshead minnows (Cyprinodon variegatus) using the ABR technique (Auditory Brainstem Response) and to investigate the effects of triclosan on hearing development. Exposure to TCS was conducted from fertilization of eggs on at concentrations likely to be found in the environment: 20, 50 and 100 µgl-1. We characterized previously the ontogenic variation of thyroid hormones in embryos and larvae of sheepshead minnows. We observed an increase of thyroid hormones level around the 12th and the 15th day post hatching (dph), that may be associated with the transition from larval to juvenile stage during the development of this species. We concluded, that this period could be defined as a critical exposure window to pollutants. We determined hearing thresholds for sheepshead minnows of different ages. Our sheepshead minnows show ontogenic variations in the hearing ability during their development. At 30 days post hatching, their hearing ability is quite bad, with a narrow bandwidth of detected frequencies. But their hearing ability considerably enhance during their development to reach the adult hearing ability at around 80 days post hatching when this species reach sexual maturity. So we observe during the developmental phase of this fish species clear ontogenic improvements of the hearing ability and they showed an ontogenetic expansion in the frequency bandwidth they were able to detect. The effects of TCS in this development have yet to be determined but will be fully discussed. This study proposes an interesting new endpoint in thyroid disruption research. [less ▲]

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See detailGenetic heritage of the Eastern Belgium Red and White breed, an endangered local breed
Colinet, Frédéric ULg; Bouffioux, Aude; Mayeres, Patrick et al

Poster (2015, August)

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See detailMathematical modeling of extracorporeal CO2 removal
Habran, Simon ULg; Dauby, Pierre ULg; Desaive, Thomas ULg et al

Poster (2015, August)

Extra¬cor¬poreal CO2 removal devices (ECCO2R) can be used in clinics to decarboxylate blood externally for patients suffering from pulmonary insufficiencies like acute respiratory distress syndrome. In ... [more ▼]

Extra¬cor¬poreal CO2 removal devices (ECCO2R) can be used in clinics to decarboxylate blood externally for patients suffering from pulmonary insufficiencies like acute respiratory distress syndrome. In this work, a model of the respiratory system coupled with such a device is proposed to analyze the decrease of CO2 partial pressure in blood as a function of blood flow through the device. This model provides a mathematical tool which could help clinicians to choose the optimal settings of ECCO2R. [less ▲]

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See detailApplication of next generation sequencing for study and diagnosis of plant viral diseases in agriculture
van der Vlugt, René; Minafra, Angelanotio; Olmos, Antonio et al

Poster (2015, August)

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See detailHow novice and expert drivers adjust their driving behavior when they feel drowsy?
Berastegui, Pierre ULg; Piette, Christine; François, Clémentine ULg et al

Poster (2015, July 29)

This paper aims to explore adaptive behaviors developed by drivers to prevent drowsiness. Specifically, we postulate that driving expertise is associated with better drowsiness awareness, allowing experts ... [more ▼]

This paper aims to explore adaptive behaviors developed by drivers to prevent drowsiness. Specifically, we postulate that driving expertise is associated with better drowsiness awareness, allowing experts to adequately adjust their driving behaviors when they feel drowsy. The present study was carried on a high-fidelity driving simulator coupled with an innovative system allowing objective sleepiness assessment based on EEG and Eye-tracking data. The Karolinska Sleepiness Scale was used to evaluate subjective drowsiness. The ratio between objective and subjective assessments gave an indicator of drowsiness awareness. Standard Deviation of Lateral Position (SDLP) was used as a measure of performance while driving speed and ocular fixations were recorded in order to highlight adaptive behaviors. 16 subjects were recruited from general population and categorized in two groups of expertise based on the Belgian Institute for Road Safety’s criteria. Our results show that expert drivers show better drowsiness awareness than novices and mobilize speed increasing and vigilance reallocation strategies to maintain satisfactory level of drowsiness. [less ▲]

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See detailProbing the conformational changes during desolvation of ions using orthogonal mobility methods (CE-IMS)
Far, Johann ULg; Kune, Christopher ULg; Delvaux, Cédric ULg et al

Poster (2015, July 29)

The transfer of ions from the solution to the gas phase is a critical step to produce « native species ». Coming from a highly solvating medium, ionic species will tend to find a new equilibrium ... [more ▼]

The transfer of ions from the solution to the gas phase is a critical step to produce « native species ». Coming from a highly solvating medium, ionic species will tend to find a new equilibrium conformation in the gas phase. The pathway to reach the thermodynamically stable conformation involves crossing potential barriers of different heights. When these barriers are too high compared to the internal energy of the ions, it will result in “partial memories” (as structural preservation) of the conformation in solution. In order to evaluate the effect of the solvent evaporation and of the various collision processes encountered by the ions in the mass spectrometer, we developed two strategies: The first strategy consists in comparing in a single experiment the shape of the ions in solution and in the gas phase. Data are obtained by coupling capillary electrophoresis with Ion Mobility Mass Spectrometry. Drift times in solution and in the gas phase are directly compared. Deviations from their correlation points out changes in folding upon desolvatation. Preliminary results show that among peptides issued from tryptic digest of BSA some of them clearly change their conformation during desolvatation. The second strategy consists in probing changes of conformation once the ions are in the gas phase. The ions are rapidly heating by collisions ions during their transfer to the IMS. The heating is obtained by increasing their collision energy, rapidly followed by thermalisation in the IMS cell. The ions may be kinetically trapped in their new conformations. This allows comparing barriers between different ions geometries. In summary this work intends to evaluate the extent of conformational “memory” of the ions of different nature for best experimental condition allowing “native mass spectrometry” [less ▲]

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See detailClostridium difficile, a new zoonotic agent. Characterization and relatedness of C. difficile strains isolated from animals, food and humans in Belgium
Rodriguez Diaz, Cristina ULg

Poster (2015, July 28)

Introduction: Clostridium difficile is an anaerobic spore-forming bacterium recognised as a major cause of nosocomial colitis and antibiotic associated diarrhea. Over the past few years, several studies ... [more ▼]

Introduction: Clostridium difficile is an anaerobic spore-forming bacterium recognised as a major cause of nosocomial colitis and antibiotic associated diarrhea. Over the past few years, several studies have focused on the possible role of animals and food as contamination routes for human C. difficile infections. Purpose: The aim of this study was to isolate and compare the C. difficile strains circulating in animals, food and humans in Belgium. Methods: Faecal samples of newborn pigs and calves were collected from breeding farms. Intestinal contents and carcasses samples were collected from cattle and pigs at slaughterhouse. Raw meat was obtained from the retail trade. Horse faecal samples were collected from hospitalized animals. Human C. difficile isolates were obtained from care home residents and hospitalized patients. C. difficile strains were compared with respect to the toxin gene profile, PCR-ribotyping, antimicrobial activity, multilocus sequence typing (MLST) and multiple-locus variable number tandem repeat analysis (MLVA). A neighbourd-joining phylogenetic three was constructed in order to determine the correlation between human, animal and food isolates. Results: A total of 127 isolates belonging to 32 different PCR-ribotypes were collected. The PCR-ribotypes most prevalent in terms of number of isolates were 078, 014 and 027. For a given PCR-ribotype, strains presented a similar susceptibility to the antimicrobials tested, irrespective of the isolation source. Phylogenetic analysis showed that human, meat and animal isolates with the same PCR-ribotype cluster in the same lineage. Significance: The overlap between strains from animal, food and human origins suggest a potential risk of interspecies and foodborne transmission. [less ▲]

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See detailSedimentological and geochemical evidence to detect arid periods recorded in wadi deposits: a case study from northern Morocco
El Ouahabi, Meriam ULg; Bartz, Melanie; Rixhon, Gilles et al

Poster (2015, July 27)

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See detailIdentification of VZV ORF9p potential cellular partners that could be important for the viral egress.
Lebrun, Marielle ULg; riva, laura; Rambout, Xavier ULg et al

Poster (2015, July 26)

ORF9p (homologous to HSV-1 VP22) is a VZV tegument protein essential for the viral replication. During the lytic cycle it is the mostly expressed gene. We have recently demonstrated that it is a substrate ... [more ▼]

ORF9p (homologous to HSV-1 VP22) is a VZV tegument protein essential for the viral replication. During the lytic cycle it is the mostly expressed gene. We have recently demonstrated that it is a substrate of the viral kinase ORF47p and that its ORF47p-dependent phosphorylation is important for the secondary envelopment process. We also have identified an acidic cluster (AC) within the protein that is important for its correct localization in the infected cells and for the interaction with ORF47p. The recombinant VZV expressing ORF9p-ΔAC presents an accumulation of capsids in the perinuclear space. ORF9p seems then to play an important role in several steps of the egress process. In this context, we sought to identify cellular partners of ORF9p that might be important for these functions. We performed a yeast two hybrid screen against the human ORFeome 5.1. and picked out 44 candidates among which 5 proteins playing roles in membrane organization and targeting. We currently are trying to confirm these interactions in infected cells and to assess the role of these interactions for the viral lytic cycle. [less ▲]

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See detailExploratory study of narratives in children with attention deficit hyperactivity disorder
Boulard, Aurore ULg; Pignatiello, Laure ULg; Leclercq, Cédric

Poster (2015, July 21)

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See detailCombining mindfulness and ACT to learn how to manage emotions and to engage in valued activities: Assessment of the feasibility of a training group and its efficiency
Wagener, Aurélie ULg; Dierickx, Christophe; Blairy, Sylvie ULg

Poster (2015, July 18)

BACKGROUND Managing painful emotions could be an issue for a lot of adults. Indeed, learning how to manage painful emotions is an often-requested demand in psychotherapy. Mindfulness-based programs and ... [more ▼]

BACKGROUND Managing painful emotions could be an issue for a lot of adults. Indeed, learning how to manage painful emotions is an often-requested demand in psychotherapy. Mindfulness-based programs and acceptance and commitment therapy (ACT) offer useful tools which aim to guide in this learning process. ACT also provide guidelines to engage in valued activities. In order to help community adults to manage their painful emotions and to engage themselves in valued activities, we offer training group cycles combining tools of mindfulness-based programs and ACT. This study aims to assess the feasibility of such training groups and their efficiency. METHODS A longitudinal design with three assessment-times (T0, T1 and T2) is employed. Participants to the training group attend to three three-hours training sessions on a six-weeks period. They are assessed before the training sessions (T0), directly after (T1) and at three-months follow-up (T2). Questionnaires assess these variables: sociodemographic data, mood, mindfulness, psychological flexibility, cognitive coping strategies and behavioural activation. Student t tests for paired samples are conducted. RESULTS Fifty-four adults participated to four training cycles (the cycles are all identical). Until now, 28 participants (21 women) completed the T0 and the T1 (mean age = 41.43, SD = 11.83). Student t test indicate a significant decrease of depression (t(25) = 4.53, p < 0,001), anxiety (t(25) = 6.23, p < 0.001) and non-adaptive cognitive coping strategies (t(24) = 3.76, p < 0.001). Student t test also indicate a significant increase in mindfulness (t(26) = -3.87, p < 0.001), psychological flexibility (t(26)) = -5.48, p < 0.001) and behavioural activation (t(26) = -4.86, p < 0.001). DISCUSSION Preliminary results indicate the feasibility of training groups combining tools of mindfulness-based programs and ACT. Results show a decrease in several variables (depression, anxiety and non-adaptive cognitive coping strategies) and an increase in other variables (mindfulness, psychological flexibility and behavioural activation). These results seem to indicate that participants benefit from the training groups. Data collection is still ongoing and a control group (waiting-list) is currently being composed. Results and clinical implications will be further discussed during the congress. [less ▲]

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See detailMetabolomics analysis of Galium odoratum (L.) Scop.: impact of the plant population origin and growth conditions.
Ledoux, Allison ULg; Martin, Bertrand; De Tullio, Pascal ULg et al

Poster (2015, July 16)

Galium odoratum is a plant used in traditional medicine and to prepare beverages. This work aimed at studying the impact of plant origin and growth conditions on the metabolite content of the plant ... [more ▼]

Galium odoratum is a plant used in traditional medicine and to prepare beverages. This work aimed at studying the impact of plant origin and growth conditions on the metabolite content of the plant. Material and methods- Aerial biomass of Galium odoratum was collected from five natural populations (in situ conditions) and from controlled environment (ex situ conditions). Results- Quantitative analysis of selected phytochemicals including phenylpropranoids and iridoids showed clear differences between the plants from nature and those of controlled growth conditions as well as internal variation within the group. The metabolomic approach emphasized the decrease of the secondary metabolites pool paralleled by an increase of the carbohydrates in ex situ conditions. Conclusion- Metabolomics approaches using 1H-NMR and HPLC is worth to consider for studying the impact of climate factors on the regulation of the phytochemical profile in relation to the origin of the plant material. [less ▲]

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See detailDevelopmental profiles of GFAP-positive astrocytes in sheep cerebellum
Salouci, Moustafa ULg; Antoine, Nadine ULg; Shikh Al Sook, Mohamad Khir ULg et al

Poster (2015, July 16)

Astroglial cells make up the largest glial population in the brain and play a variety of vital functions in the development of the CNS. Defects in the development of these cells may induce various ... [more ▼]

Astroglial cells make up the largest glial population in the brain and play a variety of vital functions in the development of the CNS. Defects in the development of these cells may induce various neurodegenerative disorders and result in neural disease. The aim of this study is to investigate the normal development of astrocytes in sheep in various zones of the cerebellum during the different stages of gestation. 19 ovine fetuses, one lamb in the first postnatal week and three adult sheep. Sections of the cerebellum were embedded in paraffin and processed for immunohistochemistry for GFAP. The current study indicates that the first appearance of astrocytes occurs around the 8th week of gestation from restricted zones in the cerebellum. Bergmann cells were present around the 15th week of gestation. Our findings suggest that the maturation of astrocytes begins in the caudal parts of the cerebellum from their initial ventral regions to dorsal regions radially within the white matter followed by the more rostral parts of the cerebellum and that the astrocytes proliferate in the vermis before the cerebellar hemispheres. Our study provide a bases for future studies focusing on the pathological changes in the CNS of both human and sheep. [less ▲]

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See detailIsolation and identification of potential antimalarial compounds from endemic plants of Reunion Island
Bordignon, Annélise ULg; Cieckiewicz, Ewa ULg; Jansen, Olivia ULg et al

Poster (2015, July 16)

Malaria is known as the most important parasitic disease around the world with 584 000 malaria deaths worldwide in 2013 [1]. Due to the problem of increased parasite resistance, natural products from ... [more ▼]

Malaria is known as the most important parasitic disease around the world with 584 000 malaria deaths worldwide in 2013 [1]. Due to the problem of increased parasite resistance, natural products from endemic plants of Reunion Island, hot spot of promising biodiversity, could represent an important source of new antimalarial drugs. The aim of this thesis research focuses on the evaluation of potential antiplasmodial activity of medicinal plants from Reunion Island. A global screening of plants extracts from Reunion Island was performed on Plasmodium falciparum 3D7 chloroquine-sensitive strain revealed by colorimetric method as described in previous reports [2]. Monimia rotundifolia was then selected due to its promising in vitro activity against Plasmodium. Bioguided fractionation was realized using Prep HPLC techniques and led to the isolation of aporphine-type alkaloids from Monimia rotundifolia leaves dichloromethane extract. Further investigations are in process to confirm the antiplasmodial activities of these alkaloids and to determine their structures. References: [1] WHO, World Malaria report 2014. [2] Jansen O. et al., Evaluation of 13 selected medicinal plants from Burkina Faso for their antiplasmodial properties. J Ethnopharmacol 2010, 130:143-150. [less ▲]

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See detailEarly Carboniferous events along the north-eastern Gondwanan margin: an example from the Mobarak Formation of the Central Alborz Mountains, Northern Iran.
Sardar Abadi, Mehrdad ULg; Da Silva, Anne-Christine ULg; Poty, Edouard ULg et al

Poster (2015, July 14)

The transition from the Late Devonian to the Early Carboniferous was marked by tectonic events, environmental change and global oceanic biological turnover that influenced sedimentary regimes. The end ... [more ▼]

The transition from the Late Devonian to the Early Carboniferous was marked by tectonic events, environmental change and global oceanic biological turnover that influenced sedimentary regimes. The end-Devonian faunal extinction event, for example, eliminated most of the reef building taxa, which, coupled with an increasing rate of subsidence in response to the opening of the Paleo–Tethys and a sea-ward shift of carbonate factories during the Lower Carboniferous, led to the formation of extensive carbonate ramp platforms along the Laurasian and Gondwanan margins. This development has already been reported from the western Gondwanan and southern Laurasian margins but not from northern to north-eastern Gondwanan margin yet. We aim to improve the knowledge on the main factors controlling the development and growth of carbonate ramps during the Lower Carboniferous by examining the Alborz basin along the northern margin of Gondwana. The Lower Carboniferous Mobarak Formation records the development of a storm-sensitive pervasive carbonate factory on the southern Paleo-Tethys passive margin following the opening of the Paleo-Tethys Ocean into the Alborz basin along the northern margin of Gondwana. Four outcrops in the central Alborz Mountains were studied: the Jaban, Aroo, Shahmirzad and Labnesar sections. Four events have been described as the principal factors controlling carbonate platform evolution in the Lower Carboniferous: (1) A transgression linked to global temperature rise in the Early Tournaisian (Middle Hastarain) resulted in the formation of thick-bedded argillaceous limestones. This interval is represented by massive beds of dark mudstones–wackestones to packstones that laterally interfinger with finely laminated limestones, and with bed thickness ranging on the centimeter to meter scale. This interval correlates with Lower Tournaisian nodular to argillaceous limestones of the Moravia Basin (Czech Republic), the Rhenish Slate Mountains (Poland) and the Dinant Basin (Belgium). (2) Late Hastarian–Early Ivorian glaciations were identified in Southern Gondwana but had not been evidenced in Northern Gondwana yet. This glaciation regime is recorded through the appearance of inner-ramp channel-form facies in mid– and outer-ramp settings. (3) During Late Ivorian–Early Visean?, a differentiation block faulting regime along the basin’s margin caused uplift of the westernmost parts of the Alborz basin and resulted in a sub-marine collapse in the eastern part of the central basin. This caused vast sub-aerial exposure and brecciation the top of the Mobarak Formation at the Jaban and Aroo sections. The sub-marine collapse was recorded through the occurrence of Zoophycos bearing fine-grained limestones in the top of the Labnesar and Shahmirzad sections. (4) Tectonic activity that coincided with considerable and abrupt sea level falls as an indirect consequence of the Viséan and Serpukhovian glaciations phases. This progressive sea level drop led to the stagnation of the carbonate factory, which is expressed as an erosional surface at the top of the Mobarak Formation. [less ▲]

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See detailDevelopment of a simple approach for ultrasensitive detection of bisphenols by multiplexed surface enhanced Raman scattering
De Bleye, Charlotte ULg; Dumont, Elodie ULg; Netchacovitch, Lauranne ULg et al

Poster (2015, July 13)

A very simple, cheap and fast SERS method using functionalized silver nanoparticles was developed to detect bisphenols. This method was applied for the semi-quantitative detection of bisphenol A (BPA ... [more ▼]

A very simple, cheap and fast SERS method using functionalized silver nanoparticles was developed to detect bisphenols. This method was applied for the semi-quantitative detection of bisphenol A (BPA), bisphenol B (BPB) and bisphenol F (BPF) separately. Afterwards, a feasibility study of performing a multiplex SERS detection of BPA, BPB and BPF was successfully carried out. Finally, this developed method was applied on real samples which were solutions comprising cash receipts collected from different stores. [less ▲]

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See detailSmall Heat Shock Proteins (sHSPs), specific markers of exercise-induced muscle damage
Hody, Stéphanie ULg; Simonet, Arnaud ULg; Lacrosse, Zoé ULg et al

Poster (2015, July 12)

Unaccustomed eccentric (ECC) exercise may cause exercise-induced muscle damage (EIMD) whereas repeating submaximal ECC sessions is known to prevent this damage. The present study aimed to better ... [more ▼]

Unaccustomed eccentric (ECC) exercise may cause exercise-induced muscle damage (EIMD) whereas repeating submaximal ECC sessions is known to prevent this damage. The present study aimed to better understand the molecular mechanisms underlying EIMD and subsequent adaptation. C57BL adult mice were submitted to different treadmill running protocols: IEE (intense ECC exercise), ET (ECC training), CT (concentric training), LT (level training), ET+IEE, CT+IEE. A 2D-DIGE proteomic analysis on mouse quadriceps muscles revealed that HSP25 and alpha-crystallin B chain were significantly more abundant in IEE, CT+IEE, ET+IEE and ET groups compared to unexercised mice. Interestingly, immunofluorescence analysis highlighted that all damaged fibers also showed positive staining for sHSPs. In contrast, sHSPs+ fibers are not necessarily damaged, suggesting that the sHSPs response precedes increased sarcolemma permeability. Our data demonstrate that ECC exercise specifically increases sHSPs expression which may represent an early marker of damage and/or adaptation of the muscle fibers to ECC contraction. [less ▲]

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See detailControlled clinical trial of repeated left prefrontal transcranial direct current stimulation in patients with chronic minimally conscious state
Thibaut, Aurore ULg

Poster (2015, July 08)

Thibaut A., Bruno MA., Wannez S., Donneau AF., Martial C., Chatelle C., Laureys S. Background: A recent study showed that single-session anodal transcranial direct current stimulation (tDCS) applied to ... [more ▼]

Thibaut A., Bruno MA., Wannez S., Donneau AF., Martial C., Chatelle C., Laureys S. Background: A recent study showed that single-session anodal transcranial direct current stimulation (tDCS) applied to the left dorsolateral prefrontal cortex (LDLPF) transiently improves consciousness in 43% of patients in minimally conscious state (MCS) (1). We here test the potential effects and safety of repeated tDCS in severely brain-damaged patients with MCS. Methods: In this double-blind cross-over sham-controlled experimental design, we delivered two sessions of repeated (5 days of stimulation) tDCS, either anodal or sham in a randomized order. We stimulated the LDLPF cortex (Figure 1) during twenty minutes in 20 MCS patients (12 men, aged 48±16 years, time since onset 78±95 months, 12 post-traumatic). Consciousness was assessed by the French adaptation of the Coma Recovery Scale Revised (CRS-R; 2) before and after each stimulation (Figure 2). Results: A treatment effect was observed for the comparison between CRS-R total scores at baseline and after 5 days of real tDCS (p<0.01). Behaviorally, 10/20 patients showed a tDCS- related improvement; 5 patients responded after the first stimulation and 5 other patients responded after 2, 3 or 4 days of stimulation (Figure 3). No side effect (e.g. epilepsy, sign of pain, drowsiness) was reported. Conclusion: Our results demonstrate that repeated (5 days) anodal LDLPF tDCS is safe and might improve signs of consciousness in about half of patients in MCS. It is important to note that the first session is not predictive for a future positive effect of the efficacy of the non-invasive electrical stimulation. References: 1. Thibaut A, Bruno MA, Ledoux D, Demertzi A, Laureys S. tDCS in patients with disorders of consciousness: sham-controlled randomized double-blind study. Neurology. 2014 Apr 1;82(13): p. 1112-8. 2. Schnakers C, Majerus S, Giacino J, Vanhandenhuyse A, Bruno MA, Boly M, Moonen G, Damas P, Lambermont B, Lamy M, Damas F, Ventura M, Laureys S. A French validation study of the Coma Recovery Scale-Revised (CRS-R). Brain Injury. 2008 Sep ;22(10): p. 786-92. [less ▲]

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See detailOpen pits or deep mines used for Underground Pumped Storage Hydroelectricity (UPSH): impacts on groundwater exchanges
Pujades, Estanislao ULg; Willems, Thibault ULg; Orban, Philippe ULg et al

Poster (2015, July 08)

UPSH using abandoned works is an attractive alternative to improve the efficiency of power plants, which cannot regulate the amount of electricity generated according to the demand (wind, solar or nuclear ... [more ▼]

UPSH using abandoned works is an attractive alternative to improve the efficiency of power plants, which cannot regulate the amount of electricity generated according to the demand (wind, solar or nuclear). UPSH plants can store (pumping water from an underground to an upper reservoir) or produce energy (releasing water from an upper to an underground reservoir) during the low or high demand periods. However, it is mandatory to determine 1) the impacts caused on aquifers and 2) the role played by the aquifer characteristics in order to assess the suitability of UPSH plants. Numerical simulations are developed in order to ascertain the groundwater flow impacts and the variables involved in the process. Given the earlier stages of our study, results are obtained considering regular pumping-injection cycles and simplifying the shape of the mine/open pit. The most noticeable effect consists in an oscillation of the groundwater. The hydraulic head around which groundwater oscillates, the magnitude of the oscillations and the time to achieve a pseudo-steady state (magnitude and head reached during oscillations do not vary anymore with time) depend on the boundaries, the parameters of the aquifer and the characteristics of the underground reservoir. [less ▲]

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See detailMethane distributions and sea-to-air fluxes in the South China Sea and the West Philippines Sea
Tseng; Chen; Borges, Alberto ULg et al

Poster (2015, July 07)

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See detailPhoto- and thermo-reversible crosslinked recyclable shape memory materials
Defize, Thomas ULg; Riva, Raphaël ULg; Thomassin, Jean-Michel ULg et al

Poster (2015, July 02)

Shape memory polymers (SMPs) are remarkable materials able to switch from a stressed deformed state (temporary shape) to their initial relaxed state (permanent shape) by the application of a stimulus ... [more ▼]

Shape memory polymers (SMPs) are remarkable materials able to switch from a stressed deformed state (temporary shape) to their initial relaxed state (permanent shape) by the application of a stimulus; such as heat or light. Typically; the shape memory property is generally observed for chemically or physically cross-linked polymers that exhibit an elastomeric behavior above a phase transition; e.g. glass or melting transition. As an example; cross-linked semi-crystalline poly(ε-caprolactone) (PCL) is widely studied for the development of SMPs. As most of SMPs are irreversibly cross-linked material; their reprocessing is impossible preventing any recycling. Thereby; reversible reactions; allowing the formation/cleavage of the network; raise tremendous interest for the development of new SMPs. Recently, we reported the preparation reversibly cross-linked PCL-based SMP using the Diels-Alder (DA) reaction between furan and maleimide end-groups of 4-arm star-shaped PCL, well-known to create reversible bonds. After implementation, this shape memory material was demonstrated to be recyclable, and was characterized by excellent fixity and recovery before and after recycling experiments. However, the relatively low retro DA temperature of the furan-maleimide adducts led to an inelastic deformation during shape memory tensile cycles. In order to get rid of this drawback, an alternative approach was investigated. The substitution of the DA reaction by a photo-reversible reaction, typically the photo-induced (2+2) cycloaddition of coumarins, was proposed to prepare cross-linked PCL matrix presenting one-way and two-way memory properties, since photolabile adducts are supposed to be stable during shape memory tensile cycles. [less ▲]

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See detailMechanisms of cell fate specification by the ARP/ASCL factors in the zebrafish digestive system
Stern, David ULg

Poster (2015, July 01)

Recently, we discovered that pancreatic endocrine cell fate in zebrafish is not controlled by Neurog3 like in mouse but by a couple of ARP/Ascl factors, Ascl1b and Neurod1. Furthermore, we identified ... [more ▼]

Recently, we discovered that pancreatic endocrine cell fate in zebrafish is not controlled by Neurog3 like in mouse but by a couple of ARP/Ascl factors, Ascl1b and Neurod1. Furthermore, we identified Ascl1a as the cell fate determinant of the secretory lineage in the zebrafish intestine while this function is fulfilled by Atoh1 in the murine intestine. These data highlighted a striking diversity in the ARP/Ascl factors involved in the determination and differentiation of the endocrine cells and showed that the choice of these factors depends not only on the organ considered but also on the species. The next question was to understand this diversity and determine whether these ARP/Ascl factors are interchangeable. We first test whether expression of Atoh1 could rescue the loss of secretory cells in the gut of the pia/ascl1a mutant by using the inducible transgenic lines Tg(hsp70:atoh1a) or Tg(Hsp70:atoh1b-Myc). We found that both lines can rescue efficiently the loss of secretory cells in the gut of the pia/ascl1a mutant. Furthermore, this rescue can be also obtained using two others ARP/ASCL factors, namely neurod1 or Ascl1b, suggesting that all these ARP/Ascl factors are interchangeable. However, the phenotype of the rescued embryos is slightly different from wild type embryos as they display an excess of goblet cells and a reduced number of enteroendocrine cells and we are currently investigating the reasons of such difference. Interestingly, we also found that the overexpression of Atho1 factors leads to ectopic endocrine cells in the liver and the anterior endoderm and the characterization of these ectopic cells will give insights about the mechanism of cell specification by the ARP/ASCL factors. [less ▲]

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See detailEvaluation of phosphorus bioavailability according to the soil organic matter content
Barbieux, Sophie ULg; Colinet, Gilles ULg

Poster (2015, July)

Phosphorus (P) is an essential nutrient for plants. The organic matter contains significant amounts of P which can be mineralized and supply soil solution. We hypothesize that increasing P organic pools ... [more ▼]

Phosphorus (P) is an essential nutrient for plants. The organic matter contains significant amounts of P which can be mineralized and supply soil solution. We hypothesize that increasing P organic pools in soils is a way to improve its progressive release for plants and alleviate risks of immobilization in mineral forms. The main objective of this study is to evaluate the P bioavailability and its uptake by plants according to the soil organic matter (SOM) content. The experimental protocol is based on a micro-culture in pots. The test-plant used is ryegrass (Lolium perenne L.). Eight silty soils were selected from vegetable gardens (5) and from a long-term fertilization trial on field (3). They present a gradient of SOM (from 2 to 9 %) and available P content (from 5 to 55 mg/100g). Plants were first grown in pure sand and P-free Hoagland nutritive solution. Ten days after plant emergence, roots were brought into contact with the studied soil during about one month. The experiment was stopped after three harvests (every 10 days) and three growth cycles. At the end of the experimentation, analyses were performed on plant material (biomass, P content) and on soil (soluble P, available P, microbial P, pH, phosphatase activity, hot water carbon, nitrate). Besides this study, an incubation experiment was carried out with the same soils without plant to assess soil P status at each harvest time. Paper will present the main findings of the experiment. Especially, the following issues should find answers: (1) do higher levels of SOM and organic phosphorus modify the evolution of P content in soil solution and its uptake by plants?, (2) are the biological processes involved in P cycling promoted in soils with higher SOM content? [less ▲]

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See detailSPECIFICITY OF CLASS I TAGATOSE 1,6-BISPHOSPHATE ALDOLASE ENHANCED TOWARD TAGATOSE 1,6-BISPHOPHATE
Freichels, Régine ULg; Delmarcelle, Michaël ULg; Colarusso, Andrea et al

Poster (2015, July)

Class I tagatose 1,6-bisphosphate aldolase catalyzes the reversible condensation of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate to produce four D-ketohexoses 1,6-bisphosphate: D-tagatose 1,6 ... [more ▼]

Class I tagatose 1,6-bisphosphate aldolase catalyzes the reversible condensation of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate to produce four D-ketohexoses 1,6-bisphosphate: D-tagatose 1,6-bisphosphate, D-fructose 1,6-bisphosphate, D-psicose 1,6-bisphosphate and D-sorbose 1,6-bisphosphate. These four sugars are diastereoisomers and differs from each other in their stereochemistry at carbons 3 and 4. The structure determination of three class I tagatose 1,6-bisphosphate aldolases has afforded new insight into their catalytic mechanism as well as their evolution. However, the determinant(s) that allow(s) the enzyme to be so unspecific at carbon 4 have remains unknown. The aim of this project is focused on the characterization of the structural features of tagatose 1,6-bisphosphate aldolases that determine the specificity of the enzyme towards tagatose versus fructose 1,6-bisphosphate (carbon C4). [less ▲]

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See detail« 11bouge » website: Principles of the designers and opinions of the practitioners
Andris, Morgane ULg; Pauly, Aurore; Mouton, Alexandre ULg et al

Poster (2015, July)

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See detailQuasar radio polarizations align with large quasar group major axes
Pelgrims, Vincent ULg; Hutsemekers, Damien ULg

Poster (2015, July)

Using quasar polarizations and a sample of large quasar groups drawn from the SDSS DR7, we showed that at HIGH REDSHIFTS (z ~ 1.5) the spin axis orientations of black holes are correlated to the major ... [more ▼]

Using quasar polarizations and a sample of large quasar groups drawn from the SDSS DR7, we showed that at HIGH REDSHIFTS (z ~ 1.5) the spin axis orientations of black holes are correlated to the major axes of the groups to which they belong. Inside very rich groups the BH spins are aligned with the major axes. When the richness decreases, the spin axes become preferentially perpendicular. [less ▲]

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See detailClose-in planets around sdB stars: A step toward constraining their masses ?
Charpinet, S.; Grandjean, A. H. M. J.; Fontaine, G. et al

Poster (2015, July)

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See detailNew asteroseismic analysis of the subdwarf B pulsator PG 1219+534
Péters, M.-J.; Van Grootel, Valérie ULg; Dupret, Marc-Antoine ULg et al

Poster (2015, July)

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

Poster (2015, July)

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

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

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See detailScreening of medicinal plants from Reunion Island for antimalarial activity
Ledoux, Allison ULg; Bordignon, Annélise ULg; Campos, Pierre-Éric et al

Poster (2015, July)

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See detailPhotocatalytic Oxidative Treatment of Waste Water contamined with Pharmaceutical Products
Vreuls, Christelle; Wilmot, Annick; Cludts, Marc et al

Poster (2015, July)

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See detailDriving Pulsation Modes in Models of the Two Pre-ELM Helium-Core White Dwarfs WASP 0247-25B and WASP 1628+10B
Van Grootel, Valérie ULg; Fontaine, G.; Brassard, P. et al

Poster (2015, July)

Multi-periodic pulsations have recently been detected in two pre-extremely low mass (pre- ELM) helium-core white dwarfs as reported in Maxted et al. (2013, Nature, 498, 463) and Maxted et al. (2014, MNRAS ... [more ▼]

Multi-periodic pulsations have recently been detected in two pre-extremely low mass (pre- ELM) helium-core white dwarfs as reported in Maxted et al. (2013, Nature, 498, 463) and Maxted et al. (2014, MNRAS, 444, 208). As such, they define a new class of pulsating stars in the HR diagram. Both objects are the secondary components in eclipsing close binaries, with solar-type main sequence stars as primaries. They are believed to be the remnants of former red giant stars stripped down of most of their mass through an active phase of binary evolution. The first of those is WASP 0247-25B, characterized by M = 0.186 ± 0.002 Mʘ, log g = 4.576 ± 0.011, and Teff = 11,380 ± 400 K (Maxted et al. 2013). Three pulsation modes have been detected so far, with periods of 381 s, 406 s, and 421 s. The second one, showing two modes with 669 s and 755 s, is WASP 1628+10B, with M = 0.135 ± 0.020 Mʘ, log g = 4.49 ± 0.05, and Teff = 9200 ± 600 K (Maxted et al. 2014). Adiabatic calculations using suitable evolutionary models have been presented in these publications, showing that the pulsation periods correspond to low-degree, mid-order p-mode oscillations (probably including radial modes). The question of the driving mechanism, however, has been left open, and we address that issue here. [less ▲]

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See detailTowards precision β-decay measurements with laser cooled 35Ar
Glover, Rohan ULg; Lenaers, Florence ULg; Velten, Philippe et al

Poster (2015, July)

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See detailThe Period-Effective Temperature Relation for DBV White Dwarfs
Fontaine, G.; Van Grootel, Valérie ULg; Bergeron, P. et al

Poster (2015, July)

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See detailLand erosion and associated evolution of clay minerals assemblages in Mediterranean region (Southern Turkey): Amik Lake
El Ouahabi, Meriam ULg; Hubert, Aurelia ULg; Lebeau, Helene et al

Poster (2015, July)

Under Mediterranean context, continuous human occupation is attested in the Amik Basin (southern Turkey) since 6000-7000 BC. The Basin also is crossed by The Dead Sea Fault (DSF), a major neotectonic ... [more ▼]

Under Mediterranean context, continuous human occupation is attested in the Amik Basin (southern Turkey) since 6000-7000 BC. The Basin also is crossed by The Dead Sea Fault (DSF), a major neotectonic structure in the Middle East extending from the Red Sea in the south to the East Anatolian Fault Zone in the north. The study focuses on the mineralogy and clay mineralogy record of the Amik Lake occupying the central part of the Basin. Our objective is to constrain major mineralogical and clay minerals evolution in the area over the last 4000 years and assess changes that would be related to the different land uses during the different Bronze, Roman, Ottoman and Modern civilizations. Sediments were collected at 1 to 2 cm intervals in core sediments up to a depth of 6 meters in the clay deposits. Geochemistry (XRF), mineralogy (XRD) and clay mineralogy are applied to study the sediment records. The age of the record is constrained combining radionuclide and radiocarbon dating. Chemical and mineralogical composition of sediments is quite diversified reflecting the significant geological variation of drainage basins. Abundant mixed-layer and partly disordered minerals characterize the different sedimentary levels recorded in those cores. Levels relatively rich in chlorite, illite and quartz are interpreted as corresponding to relatively dry periods, while more humid periods lead to more intensive weathering and consequently to the dominance of clay minerals more advanced in the relative stability scale, such as kaolinite. Smectite is taken to indicate a climate with contrasting seasons and a pronounced dry season. The sedimentary record clearly shows two periods indicating strong soil erosion in the Lake catchment. The most recent erosion phase is modern. The oldest one would have started during the late Bronze period and lasted until the late Roman Period. The first and older period is attributed to a strong aggradation linked to major increase in erosion. Our study shows that this episode has specific characteristics: mixed-layer clay mineral, high percent in Ni, Cr and Mg coupled with significant amount of organic matter of terrestrial origin. Ni and Mg most probably come from the Amanos Mountains an ophiolitic belt indicating an intensive upland cultivation and possible exploitation of its mineral resource. The second period is attributed to the modern period. The signature of the increase in erosion is different, because most of the soil cover has already been eroded. Only a patchy thin and unmature soil cover exists since the Late Roman time. Erosion is associated with a marked increase of smectite-illite interstratified clay, goethite and hematite found in deep soil horizons. Moreover, a marked increase in Cr is showed and is probably related to an enhanced exploitation of its mineral resource and to a renew land exploitation of the Amanos Mountain Range. [less ▲]

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See detailCan we trust Type Ia Supernovae as cosmological tools? - Critical analysis and alternative processing of SCP Supernovae data
Hauret, Clémentine ULg; Magain, Pierre ULg

Poster (2015, July)

Current processing to standardize Type Ia Supernovae SCP data produces a significant bias in favour of a particular cosmological model, the flat ΛCDM model. To reduce this bias, we develop an alternative ... [more ▼]

Current processing to standardize Type Ia Supernovae SCP data produces a significant bias in favour of a particular cosmological model, the flat ΛCDM model. To reduce this bias, we develop an alternative, model-independent, methodology. [less ▲]

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See detailIdentification of the main parameters controlling the plasticity of ceramic pastes: The case study of the Marrakech region (Morocco)
El Boudour El Idrissi, Hicham ULg; Daoudi, Lahcen; Fontaine, François ULg et al

Poster (2015, July)

Numerous traditional ceramic workshops occur within a range of 10 to 80 km around the city of Marrakech. Our study aims to identify the main parameters controlling the plasticity of pastes used by the ... [more ▼]

Numerous traditional ceramic workshops occur within a range of 10 to 80 km around the city of Marrakech. Our study aims to identify the main parameters controlling the plasticity of pastes used by the artisans. To reach this goal, we characterize by X-ray diffraction, granulometry and plasticity index (PI) the local raw clayey material. <br />The investigation of 26 whole pastes shows the dominance of quartz (20 to 50%) and clay minerals (25 to 60%) with K-feldspar (2 to 17%), plagioclase (2 to 25%), calcite (0 to 18%), dolomite (0 to 15%), goethite (0 to7%) and trace of hematite and anhydrite (< 3%). Amphibole occurs in trace (< 5%) but only in some samples. The clay minerals are diversified, including illite (10 to 40%), kaolinite (2 to 15%), mixed-layer (ML) (0 to 10%), smectite, vermiculite and chlorite (0 to 5%), and pyrophyllite-talc association (0 to 8%). Sepiolite (12%) is only present in one paste. The grain size is made by variable proportions of sand (5 to 65%), silt (12 to 53%) and clayey fraction (18 to 66%). <br />The Plasticity index (PI) indicates the presence of two principals groups of pastes. <br />(1) The first group is characterized by PI values ranging between 15 to 18. Their moderate plasticity behavior is related either to the low rate of clayey fraction and/or to the absence of plastic clays like smectites and mixed layer with smectitic sheets. <br />(2) The PI of second group ranges between 20 to 32. The high plasticity values are influenced by the presence of specific clayey minerals like talc-pyrophyllite or sepiolite, or by the high content of smectite plus smectitic mixed-layers within the clayey (< 2 micron) fraction. Only one sample without any of these plastic minerals but with a high content of clayey fraction is characterized by a high PI value (24). <br />We concluded that the workability of ceramic paste in Marrakech region is controlled by a combination of factors, dominated by the grain size distribution and the content in plastic clay minerals within the fine fraction. [less ▲]

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See detailComplex Magnetocapillary Microswimmers
Grosjean, Galien ULg; Vandewalle, Nicolas ULg; Lagubeau, Guillaume ULg et al

Poster (2015, July)

When particles are suspended at air-water interfaces in the presence of a vertical magnetic field, dipole-dipole repulsion competes with capillary attraction. Magnetocapillary self-assemblies, composed of ... [more ▼]

When particles are suspended at air-water interfaces in the presence of a vertical magnetic field, dipole-dipole repulsion competes with capillary attraction. Magnetocapillary self-assemblies, composed of N soft-ferromagnetic beads, have been studied as a way to produce controllable micro swimmers at low Reynolds numbers. We hereby investigate the different dynamical behaviors obtained for various self-assemblies. The dynamic interaction of a pair of particles (N = 2) generates a rich behavior at the origin of a non-reciprocal motion, being the major physical ingredient for low Reynolds locomotion. By adding particles to this elementary system up to N = 8, we create new symmetries relevant to generate translational and rotational motions. We propose a model for describing the motion driven by an external field, being the basis for developing elaborated collective behaviors. [less ▲]

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See detailDevelopment of quantification methods applied to HSS alloys for carbides volume fraction and grain size assessments
Tchuindjang, Jérôme Tchoufack ULg; Paydas, Hakan ULg; Hashemi, Seyedeh Neda ULg et al

Poster (2015, July)

High speed steels (HSS) are used in applications where enhanced mechanical properties together with hot oxidation and wear resistances are required. Such an improved physico-chemical behaviour is mainly ... [more ▼]

High speed steels (HSS) are used in applications where enhanced mechanical properties together with hot oxidation and wear resistances are required. Such an improved physico-chemical behaviour is mainly due to the presence of primary carbides within the microstructure. Depending of the initial chemical composition several types of carbides can precipitate in HSS such as MC (Nb and V-rich), M2C (Mo and W-rich), Cr-rich M7C3, etc. Two groups of HSS were analysed in this study, which are the so-called cast HSS grades that are manufactured by a centrifugal casting process and the cladded HSS manufactured by laser cladding. Purpose: Quantify the carbide volume fractions and the grain size within HSS grades in order to set correlations between the microstructure and both the mechanical and the tribological properties of the materials. Findings: The metallurgical features such as carbides nature and shape have been determined that are related to the manufacturing process of the studied material, and several methods have been used to quantify the carbide volume fractions and to assess the grain size. [less ▲]

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See detailThe microbiome from the Lyme disease principal reservoir host in southern Quebec (Peromyscus leucopus)
André, Adrien ULg; Mouton, Alice ULg; Millien, Virginie et al

Poster (2015, June 25)

The emergence of the Lyme disease in Southern Quebec appears directly linked to the recent arrival in the region of the rodent Peromyscus leucopus. Indeed, this species is considered to be the principal ... [more ▼]

The emergence of the Lyme disease in Southern Quebec appears directly linked to the recent arrival in the region of the rodent Peromyscus leucopus. Indeed, this species is considered to be the principal reservoir of the bacteria Borrelia Burgdorferei, responsible of the Lyme disease and the recent climatic warming has allowed the mice to colonize higher latitude territories. Other factors, like the regulation made by pathogens might as well play an important role in the dynamic of expansion of P. leucopus. In our project, we sampled several populations of P. leucopus from the North American border, where the species is thought to be present for 30 years, to the most recently colonized zones, situated approximatively 150km inside of the Quebec province. A characterisation of their microbiome was then performed from their liver, spleen and lungs. Our objectives are threefold: First, we settled a protocol based on NGS methods for the detection of Borrelia Burgdorferei in micro-mammal internal organs. Second, we plan to identify the Borreliosis infection zones and to study their spatio-temporal evolution. Third, we aim to test which of the central-marginal hypothesis or the enemy release hypothesis is best describing the scenario presently happening in southern Quebec concerning the distribution’s expansion of P. leucopus. These information will be of great interest to understand the dynamic of emergence of the Borreliosis and to predict the current and future distribution of this disease in order to inform the Canadian health authorities. [less ▲]

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See detailA hydrochemical - isotopic approach for assessing factors controlling the regional pollution of an urban aquifer
Gesels, Julie ULg; Orban, Philippe ULg; Popescu, Ileana-Cristina et al

Poster (2015, June 24)

The alluvial aquifer of the Meuse River is contaminated at regional scale in the urbanized and industrialized area of Liège in Belgium, in particular inorganics pollutants such as sulfate, nitrate and ... [more ▼]

The alluvial aquifer of the Meuse River is contaminated at regional scale in the urbanized and industrialized area of Liège in Belgium, in particular inorganics pollutants such as sulfate, nitrate and ammonium. The sources of those contaminants are numerous: brownfields, urban waste water, subsurface acid mine drainage from former coal mines, atmospheric deposits related to former pollutants emissions in the atmosphere ... Sulfate, nitrate and ammonium are both typical pollutants of the aquifer and tracers of the possible pollution sources. In the Water Framework Directive context, a detailed hydrogeochemical characterization of groundwater was performed. The aim is to determine the origin of the inorganic contaminations, the main processes contributing to poor groundwater quality and the spatial extent of the contaminations. A large hydrochemical sampling campaign was performed, based on 71 selected representative sampling locations, to better characterize the different vectors (end-members) of contamination of the alluvial aquifer and their respective contribution to groundwater contamination in the area. Groundwater samples were collected and analyzed for major and minor compounds and metallic trace elements. The analyses also include stable isotopes in water, sulfate, nitrate, ammonium, dissolved inorganic carbon, boron and strontium. Different hydrogeochemical approaches are combined to obtain a global understanding of the hydrogeochemical processes at regional scale. Hydrochemical interpretations are based on classical diagrams, spatial distribution maps, geochemical equations, multivariate statistics such as self-organizing maps and isotopic analyses. With this combined approach, the location of the contaminant sources and most contaminated sectors of the alluvial aquifer together with a better understanding of geochemical processes involved are obtained. Redox processes strongly influence the composition of groundwater, specifically for compounds degrading the quality of groundwater in the area (sulfate, nitrate and ammonium). The highest concentrations of sulfate can be associated with the post-mining stage in the acid mine drainage process. Various reactions involving nitrogen compounds have been identified and allow a better understanding of causes of high concentrations of ammonium and nitrate. Denitrification and sulphate reduction are also demonstrated based on isotopic ratios. [less ▲]

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See detailFate of the coactivator in the induction of BlaP β-lactamase in Bacillus licheniformis 749/I
Dauvin, Marjorie ULg; Amoroso, Ana Maria ULg; Joris, Bernard ULg

Poster (2015, June 23)

In bacteria, the production of a β-lactamase, an hydrolase specific to β-lactam antibiotics, may be constitutive or inducible. In Bacillus licheniformis 749/I the presence of a β-lactam in the external ... [more ▼]

In bacteria, the production of a β-lactamase, an hydrolase specific to β-lactam antibiotics, may be constitutive or inducible. In Bacillus licheniformis 749/I the presence of a β-lactam in the external media is detected by a protein relay producing an intracellular signal which leads to the induction of BlaP β-lactamase expression. The blaP gene is included in a divergeon along with blaI, coding for a cytoplasmic repressor, and blaR1, coding for a penicillin membrane receptor. Both, the acylation of the extracellular domain of BlaR1 by a β-lactam together with cellular stress due to the presence of the antibiotic outside the cell generate a dipeptide (coactivator) resulting from the peptidoglycan turnover that destabilizes BlaI repressor-DNA complex, leading to the expression of β-lactam resistance. [less ▲]

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See detailFULLY AUTOMATED ELECTROPHORETICALLY MEDIATED MICROANALYSIS SYSTEM FOR CYP1A1 ACTIVITY MONITORING
Farcas, Elena ULg; Servais, Anne-Catherine ULg; Lamalle, Caroline ULg et al

Poster (2015, June 23)

Introduction Since the efficacy and toxicity of drugs are closely related to their pharmacokinetics, a good understanding of metabolic pathways is important at an early stage of development. The ... [more ▼]

Introduction Since the efficacy and toxicity of drugs are closely related to their pharmacokinetics, a good understanding of metabolic pathways is important at an early stage of development. The identification of the enzymes involved in drug metabolism is thus of critical importance for the design of further clinical studies. The availability of specifically expressed human CYPs, namely supersomes, allows the investigation of the contribution of a single metabolic enzyme to the biotransformation pathway of the compound under investigation. CYP1A1, a member of the cytochrome P450 superfamily, was studied in this project. Interestingly, it has been described to be over expressed in various types of cancer. Consequently, CYP1A1 has emerged as a particularly interesting target for cancer therapy. Methods All the experiments were carried out on a HP3DCE system equipped with an on-column DAD. The EMMA procedure was performed by injecting a plug containing CYP1A1 supersomes, followed by a plug that contained the co-factor and the substrate, then another plug of CYP1A1 supersomes. The reaction was triggered by the application of a voltage switch. The voltage was then turned off to allow the metabolic reaction to occur. The separation of the components was then performed at -25 kV. Results The present study describes the development of a fully automatized in-capillary method to follow metabolization of 7-hydroxycoumarin and screen CYP1A1 inhibitors. After preliminary studies, satisfying results were obtained using CYP1A1 at a concentration of 200 pmol/mL, while the incubation time was settled to 15 min. Equal reactant plugs were injected at -50 mbar for 6 sec. The short-end injection performed gave rise to a baseline separation of the molecules (substrate, product, CYP1A1 and NADPH) in less than 2 minutes. Adequate plugs overlap was obtained using electrophoretic mixing. The DoE performed highlighted that the voltage switch has a great impact on the metabolite formation. The amount of product obtained in the optimal conditions was found to be comparable to the one detected after conventional off-line metabolization. Besides the interest of developing an automatized CE approach for metabolisation studies, we also wanted to investigate the potentiality of this approach to screen CYP1A1 inhibitors. The ability of our system to monitor CYP1A1 inhibition was undertaken with apigenin, a well-known inhibitor. It is noteworthy that the compatibility of our system with MEKC ensures its applicability to a large variety of molecules. Novel aspect Monitoring CYP1A1 activity using a rapid and fully automated EMMA method that could be used for new anticancer agents screening. [less ▲]

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See detailRecovery of language comprehension in the minimally conscious state studied by FDG-PET
Wannez, Sarah ULg; Thibaut, Aurore ULg; Vitali-Roscini, Gaia et al

Poster (2015, June 21)

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See detailUse of 16S rDNA Metagenetics and classical Microbiology to Assess the bacterial superficial Contamination Patterns in Bovines Classically Slaughtered or following the Halal Ritual
Korsak Koulagenko, Nicolas ULg; Taminiau, Bernard ULg; Hupperts, Caroline et al

Poster (2015, June 17)

In Belgium and in several European countries, two cattle slaughtering protocols exist: the classical method, that encompasses a stunning step before the sticking procedure, and the halal method, combining ... [more ▼]

In Belgium and in several European countries, two cattle slaughtering protocols exist: the classical method, that encompasses a stunning step before the sticking procedure, and the halal method, combining the stunning and the sticking in one single step. The main difference lies in the fact that, in the halal protocol, a single cut with a sharp knife is practiced directly on live cattle, instead of two cutting steps with two different knives for the sticking in the classical slaughtering technique. The unique section in the halal technique results generally in the cross section of trachea and esophagus of cattle. The aim of this study was to seek if the two slaughtering techniques were similar regarding the superficial contamination of carcasses, swabbed between 2 and 4 hours after the killing step. For this purpose, classical microbiological tests (TVC and Enterobacteriaceae) and 16S rDNA metagenetic analysis were carried out from 20 cattle carcasses (swabbing of “legal” zone – 1.600 cm2 – and in the neck area – 200 cm2). The classical microbiological results revealed no significant differences between the two slaughtering practices. Statistical analysis of pyrosequencing data showed that differences in bacterial population abundance between slaughtering methods were mainly found in the “legal” swabbing zone compared to the neck area. Bacterial genera belonging to Actinobacteria (Brevibacterium, Corynebacterium) were more aundant in “Halal” samples whereas populations from the Proteobacteria (Caulobacteraceae, Comamonadaceae, Bradyrhizobiaceae) and Firmicutes (Lactobacillus) were more abundand in the “classical” group. The analysis of OTU abundance of bacteria from the digestive or respiratory tract revealed no differences beteween groups. In conclusion, the slaughtering method does not influence the superficial microbiological pattern in terms of specific microbiological markers of the digestive or respiratory tract. However, precise analysis to the genus level underlines differences between methods, the legal swabbing zone being still the best sampling zone compared to the neckline. The next step will be the identification of precise contamination origin of the differences found between slaughtering methods. [less ▲]

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See detailBaltic seagrass meadows as a sediment carbon sink
Jankowska, Emilia; Włodarska-Kowalczuk, Maria; Michel, Loïc ULg et al

Poster (2015, June 17)

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See detailMorphological and functional characterization of Carnobacterium maltaromaticum isolated from vacuum-packed beef with long shelf life
Didimo Imazaki, Pedro Henrique ULg; Tahiri, Assia ULg; Ndedi Ekolo, François ULg et al

Poster (2015, June 17)

Temperatures near the freezing point of meat (−1.5 °C), associated with vacuum packaging, allows the preservation of this product up to several months, which makes possible the meat trade across the ... [more ▼]

Temperatures near the freezing point of meat (−1.5 °C), associated with vacuum packaging, allows the preservation of this product up to several months, which makes possible the meat trade across the planet without resorting to freezing. Other the type of packaging and the storage temperature, the shelf-life of meat is directly related to its initial microbiological ecosystem and its evolution. Carnobacterium maltaromaticum is a lactic acid bacterium, and many lactic acid bacteria associated with meat are known for their bactericidal or bacteriostatic activity against other strains, species or genera of bacteria. In this way, the presence of certain lactic acid bacteria adapted to a low temperature in fresh meat could extend the shelf life and improve the microbial stability and safety of this product. The aim of this study was to perform a morphological and functional characterization of a C. maltaromaticum strain (lab. ref. CFAUS2/DLC/4/E1) with potential bioprotective effect isolated from commercial vacuum packaged long shelf life beef. The morphological, biochemical and enzymatic profiles, the influence of different temperatures and atmospheres, and the microbial stability of fresh beef inoculated with the C. maltaromaticum strain were evaluated. Morphological, biochemical and enzymatic profiles of the isolated C. maltaromaticum strain were similar to those of two reference strains (LMG 11393 and LMG 22902). The evaluation of the influence of different atmospheres showed that the growth of C. maltaromaticum was the slowest in an atmosphere containing 70 % O2 and 30 % CO2. Vacuum packaging is therefore more suitable for the growth of this bacterium. An antimicrobial effect against Enterobacteriaceae was highlighted on inoculated fresh meat. The functional characterization of this strain will be further pursued by genotypic characterization and its potential bioprotective effect will also be studied. [less ▲]

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See detailModélisation de la mortalité de larves d'Hylotrupes bajulus (L.) par traitement anoxique pour la conservation d'objets d'intérêt patrimonial
de Streel, Géraud; Henin, Jean-Mac; Mercier, Emmanuelle et al

Poster (2015, June 16)

Au cours des dernières décénnies, les preuves scientifiques concernant les dangers des insecticides utilisés pour éliminer les insectes présents dans les œuvres d’art des points de vue de la santé du ... [more ▼]

Au cours des dernières décénnies, les preuves scientifiques concernant les dangers des insecticides utilisés pour éliminer les insectes présents dans les œuvres d’art des points de vue de la santé du personnel et des visiteurs, des risques environnementaux et des risques pour les œuvres ont conduit le monde de la conservation patrimoniale à se tourner vers des techniques alternatives de désinsectisation. Le traitement par anoxie fait partie de ces techniques. Il s’agit de soumettre les insectes à une atmosphère à faible teneur en oxygène (généralement < 0.1%) pendant une certaine durée pour les éliminer sans causer de dégât à l’œuvre ni laisser de résidus toxiques. Cette technique souffre toutefois de deux inconvénients majeurs. Le premier concerne l’importante durée de traitement nécessaire et le second concerne la sensibilité des résultats à un grand nombre de paramètres environnementaux. Cette étude a pour but d’analyser l’impact des températures élevées comme moyen pour accélérer le traitement ainsi que d’établir des modèles de mortalité intégrant certain paramètres qui influencent l’efficacité du traitement en vue de faciliter la détermination de la durée de ce dernier. Cette étude est réalisée en collaboration avec l’Institut Royal du Patrimoine Artistique (IRPA), et a également pour but de leur fournir un protocole permettant d’assurer une efficacité de traitement proche de 100%. Il a été montré que, conformément à ce qui existe dans la littérature, la température, la durée de traitement et le poids initial des larves influencent significativement la probabilité de mortalité des larves soumises au traitement tandis que le fait que la larve se situe dans une boite de Pétri ou dans une planchette de bois ne joue pas de rôle significatif. Il est également mis en évidence que, si la déshydratation des insectes lors du traitement joue un rôle important sur la mortalité, ce n’est pas le seul mécanisme impliqué. Des recherches supplémentaires sont nécessaires à ce sujet. Des modèles ont également pu être établis et ils permettent de déterminer qu’à température ambiante et 50% d’humidité du flux de gaz, la durée de traitement nécessaire pour éliminer 99% des insectes est de 26 jours [less ▲]

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See detailMicrobial diversity and function during different bioremediation strategies of diesel-polluted soil
Masy, Thibaut ULg; Hiligsmann, Serge ULg; Thonart, Philippe ULg et al

Poster (2015, June 16)

In numerous hydrocarbon-polluted sites, oxygen and pollutant bioavailability constitutes the main limiting factors for biodegradation because of the strong adsorption of hydrocarbons on organic soil ... [more ▼]

In numerous hydrocarbon-polluted sites, oxygen and pollutant bioavailability constitutes the main limiting factors for biodegradation because of the strong adsorption of hydrocarbons on organic soil particles (clay and peat). Therefore, several strategies such as biostimulation (with air/H2O2 and/or nutrients) or bioaugmentation are used, but often without understanding the endogenous microflora degrading capacity. This lack of differentiation between indigenous and added microorganisms could lead to poor predictability of the biodegradation efficiency. In addition, anaerobic degradation remains less applied in industrial settings for such compounds (especially for saturated hydrocarbons) as this process remains slow. In this context, the main objective of our study was to understand how the bacterial community evolves, in terms of species and degrading gene diversities, during the application of three different bioremediation strategies in a heavily diesel-polluted clay soil: (i) anaerobic natural attenuation, (ii) bioventing and (iii) bioaugmentation with Rhodococcus erythropolis T902.1. In addition to the supply of new degrading genes, bioaugmentation with this biosurfactant-producing strain should facilitate the bioassimilation of desorbed hydrocarbons by the whole degrading microflora. This hypothesis is strengthened by previous results obtained during several microcosm- and pilot-scale experiments. Aerobic and anaerobic microcosms were set up with three different soil samples coming from the same polluted site. Initially, their global organic content was identical but their hydrocarbon and peat concentrations were different, which led to differential oxygen consumption. Soils were sampled every 10 days to extract the DNA to measure changes in bacterial populations (with RISA analysis and 16S rRNA gene sequencing) and function (with qPCR and sequencing of degrading genes). Further analyses of the hydrocarbon content by GC-MS and of the genetic diversity by MiSeq metagenomic analysis provided detailed chemical and functional microbial data related to compound degradation and relative gene increases. Initial results showed significant differences in the microbial community structure. Moreover, Rhodococci seem to be maintained in the soil after inoculation. [less ▲]

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See detailImpacts of Plant Growth-Promoting Rhizobacteria on Wheat Growth under Greenhouse and Field Conditions
Nguyen, Minh ULg; du Jardin, Patrick ULg; Jijakli, Haissam ULg et al

Poster (2015, June 16)

Plant Growth-Promoting Rhizobacteria (PGPR) are well-known on stimulating root growth, enhancing mineral availability, and nutrient use efficiency in crops, and therefore become promising tool for ... [more ▼]

Plant Growth-Promoting Rhizobacteria (PGPR) are well-known on stimulating root growth, enhancing mineral availability, and nutrient use efficiency in crops, and therefore become promising tool for sustainable agriculture. The aim of this project is to screen PGPR strains to enhance wheat growth and yield in combination with an optimised nitrogen (N) fertilizer dose, and thus finally reduce the use of N fertilizer with equivalent yield as the recommended N dose. A list of PGPR has been collected, including (1) Mix1 (a mix of Azospirillum sp., Azorhizobium sp., and Azoarcus sp.), (2) Mix2 (a mix of Mix1 plus with two strains phosphorus-solubilizing Bacillus sp.), (3) Bacillus amyloliquefaciens a, (4) Bacillus subtilis, and (5) Bacillus amyloliquefaciens b. The PGPR were screened in both greenhouse and field condition 2014. There was significant increase in root dry weight and in root per shoot ratio of plants inoculated with Mix1 in the greenhouse. Under field condition, besides the first factor PGPR, an additional factor, i.e. four N fertilizer doses, was applied in the combination with PGPR. Without or at low N fertilizer doses, the results showed that the grain yield declined significantly. The highest grain yield increase was fifteen per cent above the control and achieved by inoculating Bacillus subtilis without application of N fertilizer. However, there was statistically insignificant in all treatments due to variability between plot replicates. Based on these results, a modified protocol plus new strategies for PGPR selection has been built up for 2015 trial to reduce the influence of variability on field and possibly achieve the higher yield increase. [less ▲]

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See detailComparative effects of freeze-drying, fluidized bed-drying and heat moisture treatment on the in vitro digestibility of dry matter, starch and protein of corn grain
Odjo, Djosse Psijus Sylvanus ULg; Malumba Kamba, Paul ULg; Migan, Sabé et al

Poster (2015, June 15)

There is some evidence that the chemical composition and nutritional value of corn is variable and may be influenced by heat treatment. This study compares the modifications induced by freeze-drying (as ... [more ▼]

There is some evidence that the chemical composition and nutritional value of corn is variable and may be influenced by heat treatment. This study compares the modifications induced by freeze-drying (as control), fluidized-bed drying and heat-moisture treatment (at 54, 90 and 130°C) of a flint corn grain and flour harvested at two different moisture content (33 and 28%, wet basis) on its digestibility assessed through in vitro methodologies. High temperature applied during fluidized-bed drying and heat-moisture treatment lead to the increase of the in vitro digestibility of dry matter. This is associated to a partial gelatinization of corn starch granules during heat treatments making them more suitable for digestion by porcine pancreatic amylase. This assumption is demonstrated by the increase of the in vitro digestibility of starch recorded with the increase of drying and heat-treatment temperature. It must be noted however, that at the same time, the digestibility of corn proteins decreased, probably because of denaturation undergo by proteins during heat treatment. It seems that there is an interaction between digestion of starch and protein, the corn starch granule being tightly embedded in a protein matrix. The extent of all of these phenomena strongly depends on availability of water which play a key but non clear role in the effect thermal history of corn grain in its nutritive value. [less ▲]

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See detailIn vitro evaluation of an anti-apoptotic drug, Z-VAD-FMK, for further use in ovarian tissue transplantation
Fransolet, Maïté ULg; HENRY, Laurie ULg; LABIED, Soraya ULg et al

Poster (2015, June 14)

Study question: In a model reproducing early ischemia after ovarian tissue transplantation, does the pan-caspase inhibitor Z-VAD-FMK could prevent granulosa cell apoptosis? Summary answer: Results ... [more ▼]

Study question: In a model reproducing early ischemia after ovarian tissue transplantation, does the pan-caspase inhibitor Z-VAD-FMK could prevent granulosa cell apoptosis? Summary answer: Results obtained with HGL5 granulosa cell line suggest that Z-VAD-FMK is efficient to protect granulosa cells from etoposide or CoCl2 induced apoptosis. What is known already: Removal, cryopreservation and subsequent graft of ovarian strips after cancer treatment have been successfully used to re-establish female fertility. However, the pregnancy rate after autografting of cryopreserved tissue is about 30%. Indeed, the major problem after transplantation is follicular loss due to ischemic reperfusion injury. Study design, size, duration: Three human granulosa cell lines (GC1a, HGL5 and COV434) were cultured during 48h with Z-VAD-FMK with or without etoposide to induce apoptosis. To reproduce the ischemic phase of the graft, cells were cultured without serum under reduced O2 (1%) or with CoCl2 (chemical hypoxia). Participants/materials, setting, methods: Granulosa cells were used as a model since they are essential for oocyte survival. Metabolic cell activity was evaluated by the WST-1 assay. Cell apoptosis was analyzed by flow cytometry after annexin V-FITC and propidium iodide double staining. The mRNA levels and protein expression of apoptotic markers were evaluated using RT-qPCR and western blot analysis. Main results and the role of chance: Flow cytometry showed that cells co-treated with etoposide and Z-VAD-FMK displayed a higher percentage of viable cells as compared to etoposide alone. When in vivo ischemic stage was mimicked (1% O2), no beneficial effect of the Z-VAD-FMK was detected. However, a significant decrease of the number of early apoptotic cells was evidenced by flow cytometry for HGL5 cells treated with Z-VAD-FMK. RT-qPCR and western blot analysis revealed that apoptotic molecules were not modulated. Metabolic activity of the 3 cell lines was reduced by CoCl2. For HGL5 cells, this decrease was partially reversed by Z-VAD-FMK. The number of viable cells was reduced by CoCl2 in HGL5 cells but Z-VAD-FMK allowed to preserve a similar number of viable and apoptotic cells than in control condition. Limitations, reasons for caution: In this study we used 3 different cell lines but granulosa cells represent only a part of the cell types present in ovarian tissue biopsies. Experiences on the effect of Z-VAD-FMK on primary culture of granulosa cells have not yet been realized. Wider implications of the findings: This study suggests that the use of an antiapoptotic drug could be efficient to improve ovarian tissue transplantation outcomes. Ovarian tissue grafting studies using our xenograft murine model will be performed to test the potential efficacy of this drug to improve tissue viability and primordial follicles preservation after transplantation. [less ▲]

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See detailStudying the great potential of cultivable bacteria associated with the brown alga Ascophyllum nodosum
Martin, Marjolaine ULg; Martin, Renée ULg; Barbeyron, Tristan et al

Poster (2015, June 09)

Bacteria associated with algae differ markedly from those living freely in seawater and represent great potential for the production of diverse bioactive compounds as they interact in multiple complex ... [more ▼]

Bacteria associated with algae differ markedly from those living freely in seawater and represent great potential for the production of diverse bioactive compounds as they interact in multiple complex ways with their host. Here we identified new bacterial species, and their polysaccharolytic activities, associated with the brown alga Ascophyllum nodosum. To isolate cultivable microorganisms, algal thalli of Ascophyllum nodosum were swabbed with sterile cotton tips and marine agar plates were inoculated. Three-hundred isolated bacteria were screened for agarase, kappa- or iota-carrageenase activities on specific marine media. Thirty-two bacteria with polysaccharolytic activities were isolated and a part of their 16S rDNA (8F-1492R) were amplified and sequenced. Twenty-seven were classified as Flavobacteriia and five as Gammaproteobacteria. Putative new strains and species of Zobellia, Maribacter, Cellulophaga, Shewanella, Glaciecola, Pseudoalteromonas and Colwellia were identified by phylogenetic analysis. Genomics libraries with their DNA were constructed in Escherichia coli and Bacillus subtilis and are currently screened for diverse enzymatic activities (agarases, iota-and kappa-carrageenases, cellulases, beta-glucosidases, sulfatases and amylases). In an era where high throughput sequencing is mostly used to study bacterial communities, cultivation methods are underestimated. Here, we revealed that only ten percent of the cultivable bacteria on this brown alga could degrade algal polysaccharides, which lead to asking us; who and what are the 90 other percents doing there? Furthermore, by this cultivation method we could also identify putative new bacterial strains/species, which are screened for polysaccharidases. Novel glycoside hydrolases from unknown marine bacteria represent great biotechnological potential as they should have original industrial properties. [less ▲]

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See detail‘Ex-situ’ preservation and characterization of Antarctic cyanobacteria in the BCCM/ULC collection
Kleinteich, Julia ULg; Renard, Marine ULg; Simons, Véronique et al

Poster (2015, June 09)

The BCCM/ULC public collection of (sub)polar cyanobacteria is funded since 2011 by the Belgian Science Policy Office. An ISO9001 certificate was obtained for the public deposition and distribution of ... [more ▼]

The BCCM/ULC public collection of (sub)polar cyanobacteria is funded since 2011 by the Belgian Science Policy Office. An ISO9001 certificate was obtained for the public deposition and distribution of strains, as part of the multi-site certification for the BCCM consortium. BCCM/ULC is currently holding 160 public cyanobacterial strains and the catalogue is available on http://bccm.belspo.be/catalogues/ulc-catalogue-search. Continuous maintenance of living cultures, some of which are also cryopreserved, ensure the preservation and the possibility to rapidly deliver strains to clients for fundamental and applied research. The main holding of the collection concerns (sub)polar strains isolated from different biotopes and representative of a large taxonomic diversity. The molecular characterization is underway, on the basis of 16S rRNA and ITS sequences, but also Multiple Locus Sequence Analysis and genome sequencing. In addition, cyanobacteria are known to produce a range of secondary metabolites (e.g. alkaloides, cyclic and linear peptides, polyketides) with various bioactive potential. The presence of genes involved in the production of microcystin is currently studied by PCR, and analytical methods are used to confirm the toxin production. Due to the geographic isolation and the strong environmental stressors of the habitat, the exploration of these metabolites in Antarctic cyanobacterial strains seems especially promising for biotechnology or biomedical applications. [less ▲]

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See detailA lysine cluster in domain II of Bacillus subtilis PBP4a plays a role in the membrane attachment of this C1 PBP.
Vanden Broeck, Arnaud; Dauvin, Marjorie ULg; Sauvage, Eric et al

Poster (2015, June 08)

Bacillus subtilis PBP4a belongs to the class-C1 PBPs characterized by two internal additional domains of unknown function. Seven lysine residues (K) are protruding from domain II. Four of them: K86, K114 ... [more ▼]

Bacillus subtilis PBP4a belongs to the class-C1 PBPs characterized by two internal additional domains of unknown function. Seven lysine residues (K) are protruding from domain II. Four of them: K86, K114, K119 and K265 have been mutated in glutamine residues (Q). Both proteins (WT and Mut4KQ PBP4a) have been produced without signal peptide in E. coli and their sub-cellular localizations determined by measuring the DD-carboxypeptidase activities in the different compartments (cytoplasmic vs membrane attached proteins). After purification, their binding to B. subtilis membranes has been compared: WT PBP4a interacts in vitro with membranes isolated from this organism in contrast to Mut4KQ PBP4a that remains entirely unbound. In absence of any amphiphilic peptide in PBP4a, the crown of positive charges on the surface of domain II is likely responsible for the PBP cellular localization in interaction with the cytoplasmic membrane. [less ▲]

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See detailExpression study of FRD3 in Arabidopsis relatives
Scheepers, Maxime ULg; Charlier, Jean-Benoit ULg; Spielmann, Julien ULg et al

Poster (2015, June 08)

Transcriptomic studies identified genes which are constitutively over-expressed in A. halleri compared to A. thaliana and which may have a role in metal tolerance or accumulation (1-3). A candidate gene ... [more ▼]

Transcriptomic studies identified genes which are constitutively over-expressed in A. halleri compared to A. thaliana and which may have a role in metal tolerance or accumulation (1-3). A candidate gene encodes FRD3, a member of the MATE family of membrane transporters (56 members in A. thaliana). It is a citrate transporter involved in iron homeostasis (4-6) and playing a role in zinc tolerance in A. thaliana (7). We are aiming to analyse the FRD3 high expression in A. halleri and the FRD3 function in zinc and iron homeostasis in A. thaliana. [less ▲]

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See detailTowards the identification of mechanisms underlying the high expression of HMA4, an essential gene for zinc hyperaccumulation in Arabidopsis halleri.
Spielmann, Julien ULg; Nouet, Cécile ULg; Scheepers, Maxime ULg et al

Poster (2015, June 08)

To maintain metal homeostasis within physiological limits independently of metal concentrations present in soil, plants developed a complex network including metal uptake, chelation, trafficking, and ... [more ▼]

To maintain metal homeostasis within physiological limits independently of metal concentrations present in soil, plants developed a complex network including metal uptake, chelation, trafficking, and storage processes. In this network, transporters have a central role. To study the molecular basis of zinc homeostasis in plants, we are using A. halleri, a zinc- and cadmium-tolerant and zinc-hyperaccumulating species representing the extreme end of natural variation in terms of metal homeostasis. Indeed, A. halleri stores high amount of metals in vacuoles of above-ground tissues (>1% Zn or 0.01% Cd in shoot dry weight). Cross-species transcriptomic studies identified about thirty genes which are constitutively over-expressed in A. halleri compared to its non-tolerant and non-hyperaccumulator sister species, Arabidopsis thaliana (1-3). HMA4 is one of these genes. It encodes a Zn/Cd plasmamembrane pump involved in xylem loading/unloading which is a key step in the hyperaccumulation process (4-5). The HMA4 overexpression is determined by a combination of gene triplication and cis-regulatory changes increasing transcription levels of each three HMA4 copies (5). We aim to identify the cis-elements underlying high expression of HMA4 in A. halleri using promoter-reporter constructs. [less ▲]

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See detailCharacterization of YbjG, a pyrophosphate phosphatase from E. coli involved in the lipid carrier undecaprenyl phosphate metabolism
Delbrassine, François ULg; Auger, Rodolphe; El Ghachi, Meriem ULg et al

Poster (2015, June 08)

•Background Undecaprenyl phosphate (C55-P) is an essential lipid carrier involved in the biosynthesis of cell surface carbohydrate polymers such as the peptidoglycan. C55-P is the result of the ... [more ▼]

•Background Undecaprenyl phosphate (C55-P) is an essential lipid carrier involved in the biosynthesis of cell surface carbohydrate polymers such as the peptidoglycan. C55-P is the result of the dephosphorylation of the undecaprenyl pyrophosphate (C55-PP) by specific phosphatases. In Escherichia coli this dephosphorylation can be performed by four integral membrane proteins, BacA, and three members of the type 2 phosphatidic acid phosphatase family (PAP2), PgpB, YbjG, and LpxT. •Objectives The aim of this project is to characterize YbjG and contributes to the understanding of the physiological role and mechanism of action of this enzyme in the C55-P metabolism. The C55-PP phosphatases could become an interesting target in the search for new molecules with antibacterial activity. •Methods In parallel the stability of YbjG and its activity against C15-PP were assessed in 94 different detergents. Moreover the enzymatic activity of YbjG was studied: substrate specificity, optimum pH and temperature, effect of detergent concentration. •Conclusions For the first time, YbjG has been purified and we show its ability to dephosphorylate C15-PP, DGPP and C55-PP in vitro with respectively decreasing efficiency. No activity has been detected on five other potential substrates (PPi, PA, C5-PP, G6P & PNPP). The phosphatase activity on C15-PP is maximum at pH 6,5 and 25 °C. Moreover Cymal6, LMNG, & ωUDM are good detergent both for the stability and the C15-PP phosphatase activity of YbjG, but approximately half of the 94 tested detergents show C15-PP phosphatase activity on the qualitative enzymatic test. [less ▲]

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See detailUNRAVELLING THE ROLES OF LYSINE ACETYLATION BY ELP3 DURING INNER EAR DEVELOPMENT
Mateo Sanchez, Susana ULg; Delacroix, Laurence ULg; Freeman, Stephen ULg et al

Poster (2015, June 06)

Given the importance of acetylation homeostasis in controlling developmental processes [1-3], we planned to investigate its role in inner ear formation and focused our attention on Elp3 acetyl-transferase ... [more ▼]

Given the importance of acetylation homeostasis in controlling developmental processes [1-3], we planned to investigate its role in inner ear formation and focused our attention on Elp3 acetyl-transferase, a member of the Elongator complex recently implicated in neurogenesis [4]. To determine the role of Elp3 in the inner ear, we first analysed the spatio-temporal pattern of ELp3 mRNA expression and showed that it was expressed in the entire early otocyst at E11.5 and persisted later in the sensory epithelium of the cochlea (the organ of Corti), in the spiral ganglion, in the stria vascularis and in the vestibule. To unravel in vivo functions of Elp3 in the inner ear, we used conditional knock-out mice in which Elp3 gene is deleted from early otocyst (Elp3 cKO). We submitted these mice to a battery of vestibular testing (i.e. stereotyped circling ambulation, head bobbing, retropulsion, and absence of reaching response in the tail-hanging test) and found significant abnormalities. Besides, the auditory brain stem response of Elp3 cKO indicated that these mice are severely deaf. At the cellular level, we did not find any structural abnormalities nor cell patterning defects that could explain deafness or balance dysfunction in Elp3 cKO mice. However, we detected some defaults in the planar orientation of their auditory hair cell bundle. We were also able to demonstrate an increased level of apoptosis in the Elp3 cKO spiral ganglion at E14.5 leading to a reduced number of neurons and fibers innervating the cochlear hair cells as well as a reduced number of their synaptic ribbons at P15. Moreover, the remaining spiral ganglion neurons extend processes showing clearly defects regarding hair cells innervation (misorientation of fibers). In conclusion, our results clearly show a role for Elp3 both in hearing and balance. We plan to go deeper in the mechanisms involved through the identification of the proteins that are targeted for acetylation by Elp3. [less ▲]

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See detailDesign and synthesis of PET-probes targeting AMPA-subtype receptors
Deverdenne, François ULg; Claes, Giselle ULg; Goffin, Eric ULg et al

Poster (2015, June 05)

The AMPA subtype of glutamatergic receptors is the main actor in the excitatory neurotransmission in the mammalian central nervous system. These receptors are involved in the expression and the ... [more ▼]

The AMPA subtype of glutamatergic receptors is the main actor in the excitatory neurotransmission in the mammalian central nervous system. These receptors are involved in the expression and the maintenance of the long-term potentiation, a phenomenon closely linked to cognitive and memorization processes. Based on experimental data collected in recent years, the use of AMPA potentiators seems to be an interesting approach in the treatment of cognitive deficits (e.g. Alzheimer disease), schizophrenia or depression. Such AMPA signal potentiation could be mediated by positive allosteric modulators (PAMs) of the AMPA receptors, a class of compounds able to produce a fine signal tuning in the presence of the endogenous ligand in the synapse, providing less toxicity than direct agonists. With this approach, the laboratory of Medicinal Chemistry of Liège university developed many series of AMPA potentiators , among which 1,2,4-benzothiadiazine 1,1-dioxides (BTDs). In order to better understand the in vivo mapping of AMPA receptors and its evolution in neurological diseases, the present work aims at developing the design and the synthesis of BTDs positive allosteric modulators radiolabeled with a fluorine-18 atom. Based on previously synthesized series in this field, we investigate the synthesis of a new class of high-affinity AMPA potentiators characterized by the presence of a fluorine atom at selected positions on the structure of the AMPA potentiators. Thanks to in vitro pharmacological evaluations, we will further determine the best candidates for their fluorine-18 radiolabeling. [less ▲]

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Peer Reviewed
See detailCXCR7/ACKR3 is activated by chemokines from both CXC and CC subfamilies
Szpakowska, Martyna ULg; Counson, Manuel; Beaupain, Nadia et al

Poster (2015, June 05)

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See detailSpatio-temporal dynamics of β-tubulin isotypes and acetyl-alpha tubulin during the development of the sensory auditory organ in rodents.
Renauld, Justine ULg; Thelen, Nicolas ULg; Johnen, Nicolas ULg et al

Poster (2015, June 05)

The auditory organ is a highly specialized structure composed by specific cellular types. The sensory cells are characterized by stereocilia at their apex and are necessary for the sound perception. These ... [more ▼]

The auditory organ is a highly specialized structure composed by specific cellular types. The sensory cells are characterized by stereocilia at their apex and are necessary for the sound perception. These cells are supported by supporting cells. Supporting cells possess a characteristic cytoskeleton in direct relation with their morphological features and their development. There are different β-tubulin isoforms in microtubules of vertebrate tissues. However, their functional significance is still largely unknown. In the present study, we investigated the localization of five β-tubulin isotypes (β 1 to 5) as well as acetyl-α-tubulin within the hearing organ during development in rodents. By using confocal microscopy, we showed that with the exception of the β3-tubulin isoform that was specific to nerve fibres, all the different β-tubulin isoforms and acetyl-α-tubulin were mainly present in the supporting cells. Contrary to β1-4-tubulins, we also found that the β5-tubulin isoform appeared only at a key stage of the postnatal development in specific cell types (pillar cells and Deiters’ cells). By using transmission electron microscopy, we revealed further that this developmental stage coincided with the formation of two separate bundles of microtubules from a unique one in these supporting cells. In conclusion, these results suggest that the β5-tubulin isoform might be involved in the generation of new microtubule bundles from a pre-existing one. [less ▲]

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See detailSimulations of the auroral signatures of Jupiter’s magnetospheric injections
Dumont, Maïté ULg; Grodent, Denis ULg; Radioti, Aikaterini ULg et al

Poster (2015, June 04)

Jupiter’s ultraviolet auroral emissions are divided into four main components: the polar emissions, the main emission, the satellite footprints and the outer emissions. The morphology of the outer ... [more ▼]

Jupiter’s ultraviolet auroral emissions are divided into four main components: the polar emissions, the main emission, the satellite footprints and the outer emissions. The morphology of the outer emissions can be either diffuse, arc-shaped or compact emissions. In the present study, we focus on outer emissions clearly detaching from the main emission and forming compact structures that are evolving regardless of the rest of the auroral emission. These auroral features were selected because they have the same appearance as the auroral signature of a clearly identified injection previously observed by Mauk et al. [2002] at Jupiter, based on simultaneous Galileo spacecraft and Hubble Space Telescope measurements. Here, we report on the evolution of those ultraviolet auroral features appearing in Hubble Space Telescope images of the northern and southern Jovian hemispheres. We investigate the possibility that those ultraviolet auroral structures are associated with energetic particle injections. For this study, we analyze the temporal variations of the longitudinal extent and of the brightness of the auroral structures. Indeed, the injected charged particles drift at different rates due to energy-dependent gradient and curvature drifts, which leads to an increase with time of the longitudinal extent of the feature and of its associated auroral signature. Since the injected energy follows the same trend, the brightness decreases with time. Different processes can generate auroral signatures of plasma injections. We simulate them by considering that pitch angle diffusion is generated by the precipitating energy flux in the ionosphere and whistler-mode waves through electron scattering. We compare the characteristics of the simulated signature with the observed parameters. Following this comparison, we are able to test whether the aforementioned mechanism is responsible for the auroral emission and to infer the typical energy and the spectral index of the energy distribution of the electrons involved in the injection process. [less ▲]

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See detailCritical periods and critical values explaining fluxes inter-annual variability in a temperate mixed forest
Hurdebise, Quentin ULg; Vincke, Caroline; De Ligne, Anne ULg et al

Poster (2015, June 04)

In order to explain inter-annual variability of Net Ecosystem CO2 Exchange (NEE) above a mixed temperate forest, two approaches were followed: •Detection of critical periods using the R-squared of the ... [more ▼]

In order to explain inter-annual variability of Net Ecosystem CO2 Exchange (NEE) above a mixed temperate forest, two approaches were followed: •Detection of critical periods using the R-squared of the regression between annual NEE and cumulated NEE on a mobile window. •Identification of critical values of a threshold used to decompose annual and seasonal NEE in two components. [less ▲]

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