References of "Poster"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailThe influence of genetic selection on the milk fatty acid profile of spring calving dairy cows
Mc Parland, Sinead; Berry, Donagh; Coleman, J. et al

Poster (2010, April)

Detailed reference viewed: 16 (3 ULg)
Full Text
See detailLipase-assisted synthesis of potential bio-based surfactants starting from lignocellulosic carbohydrates
Richard, Gaetan ULg; Nott, Katherine ULg; Paquot, Michel ULg et al

Poster (2010, April)

Surfactants constitute an important class of compounds with a lot of applications, especially in the food and beverage industries (emulsion forming and stabilization, antiadhesive and antimicrobial ... [more ▼]

Surfactants constitute an important class of compounds with a lot of applications, especially in the food and beverage industries (emulsion forming and stabilization, antiadhesive and antimicrobial activities)1. With the prospect of synthesising new active compounds, white biotechnology offers efficient tools. Indeed, the use of enzymes as biocatalysts provides an interesting synthetic route in comparison to the chemical way that often requires high reaction temperatures and suffers from a lack of specificity, resulting in complex mixtures. Among all the biocatalysts available, lipases represent a class of industrial interest 2,3. In parallel, the starting material is also an important parameter : due to the depletion of petroleum reserves, its ever increasing price and various environmental aspects, the use of renewable or biomass resources is inevitable. Within the frame of a biorefinery project, we focused on the lipase-assisted modification of uronic acids. These carbohydrates can be obtained from lignocellulosic material, and, in the presence of fatty alcohols, the Candida antarctica lipase B catalyses the synthesis of amphiphilic compounds. Owing to the initial conditions used and the addition of co-solvents, we optimized the synthesis of these bio-based potential surfactants, and obtained a panel of various structures depending to the acyl acceptor used. The poster will present the details of these syntheses. [less ▲]

Detailed reference viewed: 39 (1 ULg)
Peer Reviewed
See detailAtopy controlling loci in Czech and Russian populations
Gusareva, Elena ULg; Badalová, Jana; Havelková, Helena et al

Poster (2010, April)

Detailed reference viewed: 12 (2 ULg)
Full Text
Peer Reviewed
See detailEvaluation of climate changes impact on the hydrological behaviour of the peaty mediums - Application to the Haute Lesse-Ourthe area (Belgium).
Sohier, Catherine ULg; Dautrebande, Sylvia; Degre, Aurore ULg

Poster (2010, April)

The peaty and wet mediums have a very important role to play in term of biodiversity conservation, hydrologic pattern regulation, fauna habitat and landscape value. In the Haute Lesse – Ourthe catchments ... [more ▼]

The peaty and wet mediums have a very important role to play in term of biodiversity conservation, hydrologic pattern regulation, fauna habitat and landscape value. In the Haute Lesse – Ourthe catchments (Saint-Hubert), numbers of these mediums were strongly modified by a drainage network. This drainage network was implemented to permit a forestry production focussed on the Spruce. It has severely disturbed the hydrological cycle. The study consists in modelling the impacts of restoration practices carried out notably within the framework of the LIFE European project on the hydrological behaviour of the peat bog. Then we modelled the effect of climate change. Physical properties and retention curve of peaty materials were characterized on the basis of undisturbed samples using the Richards’apparatus. Calculations were carried out with the hydrological model EPICgrid (GxABT). The model was initially validated on several reference catchments of the study zone. It was then applied at local scale for various peaty mediums (peat type, drainage characteristics, vegetation type) and for current and future climatic conditions. A regional simulation was finally carried out in order to evaluate the impacts of peat bogs restoration measures at catchment scale. Simulations highlighted the differences in physical and hydrous properties of the different peat types (“true” peat and “degraded” peat). Local and regional impacts of peat bogs restoration on their hydrological behaviour have been evaluated. Eventually, simulations allowed us to evaluate climate change’s impact on the hydrological behaviour of the peaty mediums. The model showed notably that future climatic conditions could generate severe droughts which can become critical in some situations. [less ▲]

Detailed reference viewed: 23 (3 ULg)
Full Text
Peer Reviewed
See detailApproach of regionalization of low flow of the Walloon Region
Gailliez, Sébastien; Degre, Aurore ULg

Poster (2010, April)

The walloon part of the Meuse’s watershed represents 12283 km² and 17694 km of river. The anthropogenic pressure is important (population density is more or less 200 inhabitants/km²). In low flow period ... [more ▼]

The walloon part of the Meuse’s watershed represents 12283 km² and 17694 km of river. The anthropogenic pressure is important (population density is more or less 200 inhabitants/km²). In low flow period, water scarcity can touch both the water users (producer of drinking water and hydropower, tourism and pleasure activities and kayaking) and the river itself affecting the ‘good environmental state’ (context of Water Framework Directive 2000/60/CE). The operational management of rivers during low flow periods needs a deep knowledge of this drought phenomenon including an analysis of low flow severity and its occurrence probability. It also needs the computation of low flow discharge at any point of a river based on available hydrologic variables. The aim of this study is the low flows’ regionalization in the Walloon Region. First of all, the time series of flow data are filled in and validated. The quality is then controlled. The different tests are the determination of the minimum year requirement for a monitoring site, homogeneity tests, verification of presence or absence of summer alga and the proportion of extrapolation of the discharge rating curve Secondly, homogeneous regions will be defined and regression equations will be build. These equations will establish the relation between low flow and physical parameters (watershed area, pedology, slope), climate ones and/or ground water ones. The regression model will permit the computation of low flow discharge at any point of an ungauged river. [less ▲]

Detailed reference viewed: 32 (9 ULg)
Full Text
Peer Reviewed
See detailA pendulum test as a tool to evaluate viscous friction parameters in the equine fetlock joint
Noble, Prisca ULg; Lumay, Geoffroy ULg; Coninx, Marc ULg et al

Poster (2010, April)

This study describes an equine fetlock joint pendulum test, and investigates the influence of post mortem time and intra-articular lipid solvent on the viscous frictional response. Fresh equine digits ... [more ▼]

This study describes an equine fetlock joint pendulum test, and investigates the influence of post mortem time and intra-articular lipid solvent on the viscous frictional response. Fresh equine digits (control group 1 (n = 6); lipid solvent group 2 (n = 6)) were mounted in a pendulum tribometer. Assuming that pendular joint damping could be modelled by a harmonic oscillator fluid damping (HOFD), damping time (t), viscous damping coefficient (c ) and friction coefficient (µ) were then followed for 5 hours under experimental conditions (400 N; 20 °C). In all experiments, pendular joint damping was found to follow an exponential decay function (R² = 0.99714), which confirms that joint damping is fluid. The evolution of t, c and µ was found to be significantly (P <0.05) different in the two groups. Indeed, t decreased and c and µ increased more rapidly and strongly in the group 2. It was concluded that pendular joint damping can be modelled by an HOFD model. The influence of post mortem time on results suggests that, ideally, joint mechanical properties should only be tested on fresh cadavers at the same post mortem time. Finally, the addition of lipid solvent was found to be responsible for upper viscous friction parameters and for a reduced damping time, which suggests that articular lubricating ability was compromised. This equine pendulum test could be used to test the efficacy of various bio-lubricant treatments. [less ▲]

Detailed reference viewed: 63 (13 ULg)
Full Text
Peer Reviewed
See detailMICROPOLLUTANTS ISSUES: A MODELLING STUDY OF HEAVY METALS WITHIN TWO FRENCH BASINS AND A TEST APPLICATION TO COCAINE IN BELGIUM
Deliège, Jean-François ULg; Everbecq, Etienne ULg; Grard, Aline ULg et al

Poster (2010, April)

European policies (European Framework Directive: Water 2000/60/CE, Directive 76/464/CE) impose to reduce the releases of about a hundred substances in surface water. In the last years, the AQUAPOLE has ... [more ▼]

European policies (European Framework Directive: Water 2000/60/CE, Directive 76/464/CE) impose to reduce the releases of about a hundred substances in surface water. In the last years, the AQUAPOLE has been involved in two studies related to this matter. First, on the request and with the financial support of both the French Ministry of Environment and ONEMA (“Office National de l’Eau et des Milieux Aquatiques”), INERIS (“Institut National de l’Environnement Industriel et des Risques”) drew up the guidelines of a methodology allowing fixing the local Limit Values to Emission so as to abide by the quality standards on the whole watershed. Within this context, INERIS wishes to test the use of pollutant transfer models on pilot sub-basins. The PEGASE model has been used to simulate micropollutants on two concrete use cases (1): (iii) in the Meuse sub-basin, managed by the French Water Agency Rhine-Meuse, for simulations concerning cadmium and zinc; (iv) in the Adour sub-basin, managed by the French Water Agency Adour-Garonne, for simulations applied to cadmium and copper. The choice of each substances and sub-basins was made by mutual agreement between INERIS, the concerned Water Agencies, and the AQUAPOLE. A major selection criterion for the substances and the sub-basins was the availability of data (sources and in situ measurements). For the second study, the PEGASE model has been adapted to describe the cocaine’s behaviour (using a stable metabolite of the cocaine in the environment: the benzoylecgonine (BZE)) in waste water, waste water treatment plants (WWTP) and surface water (2). The cocaine is newly described in the model as an additional micropollutant (PEGASE already treats numerous heavy metals), thanks to the implementation of new state variable equations and their specific parameterizations. Simulations of BZE have been done in the Walloon and Flemish regions, where many measurements from the COWAT project (3) were available. The first results are showing good agreement between calculated and measured values. The ability of the model to simulate the fate of studied micropollutants (cadmium, zinc, copper, and the cocaine derivatives) in surface waters should be enhanced and extended to other substances and basins. Moreover, additional data still have to be collected and measured. [less ▲]

Detailed reference viewed: 70 (17 ULg)
Full Text
See detailSeaDataNet regional climatologies: an overview
Troupin, Charles ULg; Ouberdous, Mohamed ULg; Barth, Alexander ULg et al

Poster (2010, March 29)

Detailed reference viewed: 44 (2 ULg)
Full Text
See detailGODIVA: a 4-dimension implementation of DIVA
Troupin, Charles ULg; Ouberdous, Mohamed ULg; Beckers, Jean-Marie ULg

Poster (2010, March 29)

Detailed reference viewed: 30 (0 ULg)
Full Text
Peer Reviewed
See detailVariation in external morphology of resident bottlenose dolphins (Tursiops truncatus) in Bahia San Antonio, Patagonia, Argentina.
Vermeulen, Els ULg; Cammareri, Alejandro

Poster (2010, March 22)

Two geographic variations of bottlenose dolphins were described in Argentina (Bastida & Rodriguez, 2003); bottlenose dolphins characterized by their triangular dorsal fin shape (coast of the province of ... [more ▼]

Two geographic variations of bottlenose dolphins were described in Argentina (Bastida & Rodriguez, 2003); bottlenose dolphins characterized by their triangular dorsal fin shape (coast of the province of Buenos Aires), and bottlenose dolphins characterized by their falcate dorsal fin shape (coast of the province of Chubut). It was stated that `their clear difference would indicate that both geographic forms are isolated¿ (Bastida & Rodriguez, 2003 p.137). A photo-identification study carried out in Bahía San Antonio (BSA), North Patagonia Argentina, showed a similar variation in external morphology among year-round resident bottlenose dolphins. Out of the 15 bottlenose dolphins considered year-round resident in the bay (Vermeulen & Cammareri, 2009), three are clearly distinguishable by a more falcate dorsal fin, a darker coloration and a notably shorter beak. These individuals, with one associated calf, were first identified in September 2008 and could be re-identified in the study area up to 13 days over all the different seasons. On all occasions, they were re-identified in close association with each other and on 10 occasions in close association with triangular dorsal fin shaped bottlenose dolphins. Behavioural observations made during these associations indicated that these mixed dolphin groups were 18% of their time feeding, 18% socialising, 17% slowly travelling and resting, 16% travelling in medium and fast speed and 7% milling (n=380 min). Although both forms show variations in external morphology, the extent to which this phenotypic variation is genetically correlated remains unknown. A clear insight on the differentiation between these regional forms might have important conservation implications for this species in Argentina. [less ▲]

Detailed reference viewed: 17 (0 ULg)
Full Text
See detailImpact of the crystallisation pathway of inulin on its mono-hydrate to hemi-hydrate thermal transition
Ronkart, Sébastien; Deroanne, Claude; Paquot, Michel ULg et al

Poster (2010, March 22)

Inulin plays a major role in the food industry as dietary fibre, bulking agent and fat or sugar substitute. Thermal properties of two inulins obtained from different crystallisation pathways were ... [more ▼]

Inulin plays a major role in the food industry as dietary fibre, bulking agent and fat or sugar substitute. Thermal properties of two inulins obtained from different crystallisation pathways were investigated. The first one, was obtained by fractional precipitation of a saturated inulin solution (40/120). The second one, came from a solid amorphous inulin (95/120). These two inulins were spray dried with an inlet air temperature of 120°C. Then, these powders were placed into controlled atmosphere conditions at 0 % HR during one week and at 94% during the same time. Finally the two inulins were called 40/120/94% and 95/120/94% and their thermal properties were investigated by Wide angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), temperature resolved wide angle X-ray scattering (TRWAXS) and thermogravimetry (TGA).Although WAXS did not show any difference between the two inulin, thermal analysis revealed the existence of a hemi-hydratate inulin (40/120/94%). This fact has an implication on the processing of the powder at an industrial level. Indeed, 40/120/94% has shown an agglomeration whereas 95/120/94% was a continuous mass. In other words, polymorphism of inulin crystals induces technofunctionality changes of the powder (hygroscopy, solubility, etc.) which could have an impact during processing or formulation of the powder. [less ▲]

Detailed reference viewed: 49 (14 ULg)
Full Text
Peer Reviewed
See detailNanocoatings of inorganic surfaces by molecular biomimetic
Vreuls, Christelle ULg; Genin, Alexis ULg; Zocchi, Germaine ULg et al

Poster (2010, March 22)

Detailed reference viewed: 57 (20 ULg)
Peer Reviewed
See detailPostoperative sialadenitis with chronic brachial plexopathy
Reuter, Gilles; Racaru, Tudor ULg; Nguyen khac, Minh-Tuan et al

Poster (2010, March 20)

Detailed reference viewed: 28 (2 ULg)
Full Text
Peer Reviewed
See detailRelease of cardiac biomarkers after an intense physical exercise: preliminary results
Le Goff, Caroline ULg; Laurent, Terry; Chapelle, Jean-Paul ULg et al

Poster (2010, March 20)

Background: Over the past 2 decades, there has been a large interest in cardiac markers elevations, which are often seen following endurance sport events. These elevations were transient, with levels ... [more ▼]

Background: Over the past 2 decades, there has been a large interest in cardiac markers elevations, which are often seen following endurance sport events. These elevations were transient, with levels decreasing to pre-event concentrations within 24-48 hours. This might be explained by the relatively short half-life of studied markers, or water imbalance during and after the event. Therefore, the present preliminary study aimed to examine the increase in N-terminal pro-brain natriuretic peptide (NT-proBNP), highly sensitivity cardiac troponin T (hsTnT) and I (TnI II), myoglobin, creatine kinase muscle – brain (CK-MB), myeloperoxydase (MPO) and Highly sensitive C-reactive protein (hs-CRP) elevations after prolonged strenuous exercise . Materials and methods: Blood samples (EDTA plasma and heparinised plasma) were drawn at baseline, after 45, 90, 105, 165, 225, 285, 345, 690 and 1440 minutes in two healthy persons (29 year, trained 6 hours per week; 23 year, untrained). Each subjects runs at the maximal possibility during 2 hours. Results: For the untrained person, level of NT-proBNP exceeded the upper reference limits 12 hours after exercise but increased in all times. HsTnT and TnI II levels were upper the reference limit respectively 45 minutes and directly after exercise and increased up to 4 hours after exercise. We reported a decrease of these concentrations above the reference limits after 24 hours. Myoglobin increased after 45 minutes until 5 hours after exercises. It decreased after the 5th hour to be normalized 24 hours after exercise. CK-MB increased directly after the exercise and was upper the reference limits 165 minutes after the exercise. Level of MPO was very high just after exercise and decreased quickly in the following hours to be just upper the limit references 24 hours after exercise. HsCRP levels increased after 105 minutes and continued to increase after 24 hours. For the trained subject, we noted the same profile of increase of cardiac markers levels stayed but in the range of reference. Conclusion: These cases are extremely interesting. Indeed, this observation suggested a physiological counter regulatory process rather a simple increase of myocardial damage related to the intensity of exercise. In fact, for this moment, we do not know if the release of cardiac markers is physiological or pathological thus it must be studied. This preliminary study on endurance training suggested that intensively is determinants of the rate and the magnitude of subsequent cardiac marker release. These results suggested that an adaptation mechanism could exist. Benefits and possible long-term negative aspects of prolonged exercise should be evaluated with a more important population of athletes. [less ▲]

Detailed reference viewed: 73 (11 ULg)
Full Text
Peer Reviewed
See detailGPS™ II and GPS™ III: comparison of obtained platelets concentrations
Kaux, Jean-François ULg; Le Goff, Caroline ULg; Renouf, Julien et al

Poster (2010, March 20)

Introduction: Recently, several researches, essentially in vitro, demonstrated the positive effects of platelets on healing process of different tissues: bones, muscles and tendons. The aim of this study ... [more ▼]

Introduction: Recently, several researches, essentially in vitro, demonstrated the positive effects of platelets on healing process of different tissues: bones, muscles and tendons. The aim of this study is to compare the obtained platelets concentration between the new GPS™ III and GPS™ II. Methods: Two blood samples of 52 mL were taken in 5 volunteers and transferred respectively in both GPS™ II and GPS™ III. These devices were centrifuged at 3200 RPM during 15 min. The platelet-rich plasma (PRP) was thus collected and transferred in 6 mL test tubes. Cells count was done using an analyser ABX Micros 60. Results and conclusion: Platelets concentrations were more important from 6.2 up to 9.2 times with GPS™ II and from 7.3 up to 8.3 times with GPS™ III compared to blood samples. Efficiency of the collected platelets was around 92% for GPS™ II and 96% for GPS™ III. Both techniques made it possible to collect platelets but, unfortunately, also a lot of red and white blood cells. None of these parameters showed any significant difference (p>0.05). Conflicts of interests: The 10 devices GPS™ II and GPS™ III were provided gracefully by the firm Biomet Biologics TTC. [less ▲]

Detailed reference viewed: 109 (16 ULg)
Full Text
Peer Reviewed
See detailComparison between platelet-rich plasma (PRP) and vascular endothelial growth factor-111 (VEGF-111) as a therapeutic tool in tendon healing process
Kaux, Jean-François ULg; Drion, Pierre ULg; Libertiaux, Vincent ULg et al

Poster (2010, March 20)

Introduction In spite of the availability of various treatments for tendinopathy, this pathology often becomes chronic. For this reason, it is of interest to develop new treatments. Among them, the ... [more ▼]

Introduction In spite of the availability of various treatments for tendinopathy, this pathology often becomes chronic. For this reason, it is of interest to develop new treatments. Among them, the injection of platelet-rich plasma (PRP) seems to be a promising one. Indeed, several animal models have demonstrated that injection of blood platelets can initiate and stimulate tendon and ligament repair by releasing growth factors (GF) locally. Among all the GF released by activated platelets, the vascular endothelial growth factor-A (VEGF-A) is known to induce positive effects on vascular function and angiogenesis, and could be implicated in the healing process of tendons. Recently, a novel VEGF-A isoform was identified, the VEGF-111, a biologically active and proteolysis-resistant VEGF-A isoform, also known to present beneficial effects on ischemic diseases. This prompted us to evaluate whether VEFF-111 would have a therapeutic interest within the framework of the tendon pathology. Aim of the study: We hypothesized that the healing of ruptured Achilles tendons, which is the last stage of the Blazina’s classification, could be improved by injection of VEGF-111 that was compared to the potential effect of PRP injections using a rat model. Methods: A 5mm defect was surgically induced in rat Achilles tendon after resection of plantaris tendon. Rats were divided into 3 groups: A: control (no injection), B: PRP treatment and C: VEGF-111 treatment. Rats received a local injection of PRP (50µL) or VEGF-111 (100ng) in situ after the surgery and were placed in their cage without immobilization. After 5, 15 and 30 days, the rats were euthanized in each group. The traumatized Achilles tendon of each rat was removed and dissected during the healing process. Immediately after sampling, tendons were submitted to a biomechanical tensile test up to rupture, using a “Cryo-jaw”. Results: Our results show that developed force necessary to induce tendon rupture during biomechanical tensile test was more important for tendons which had received an injection of PRP or VEGF-111. Moreover, the tensile force necessary to break tendons is higher with PRP than with VEGF-111. These results were already noticed from day 5 onwards. Conclusion: This experimentation has shown that both PRP and VEGF-111 injections stimulated tendon healing process as suggested by the increased force needed to break tendons during its healing process. Furthermore, this acceleration of the cicatrisation process was more significant with PRP than with VEGF-111. This could be explained by the release from platelets of a “cocktail” of growth factors acting in synergy on the healing process. Acknowledgement This experimentation was partially financed by “Standard de Liège 2007” and “Lejeune-Lechien 2008” grants. [less ▲]

Detailed reference viewed: 130 (33 ULg)
Full Text
See detailMagnetic hybrid based on iron oxide nanoparticles and thermoresponsive block copolymer for biomedical applications
Sibret, Pierre ULg; Aqil, Abdelhafid; Zhao, J. et al

Poster (2010, March 18)

Detailed reference viewed: 29 (4 ULg)
Full Text
See detailTargeting nanoparticles to M cells with non-peptidic ligands for oral vaccination
Freichels, Hélène ULg; Fievez, Virginie; Plapied, Laurence et al

Poster (2010, March 18)

Detailed reference viewed: 44 (8 ULg)
Peer Reviewed
See detailZebrafish as model in toxicology/pharmacology.
Voncken, Audrey ULg; Piot, Amandine ULg; Stern, Olivier ULg et al

Poster (2010, March 17)

Detailed reference viewed: 87 (35 ULg)
Peer Reviewed
See detailComparing deviancy training in three groups of adolescents : qualitative and quantitative data
Mathys, Cécile ULg; Born, Michel; Shaw, Daniel

Poster (2010, March)

Detailed reference viewed: 17 (4 ULg)
Peer Reviewed
See detailStudy of the role of miR-21 in the regulation of angiogenesis
Sabatel, Céline; Malvaux, Ludovic; Bovy, Nicolas ULg et al

Poster (2010, March)

Detailed reference viewed: 17 (1 ULg)
Peer Reviewed
See detail16K human prolactin is an anti-lymphangiogenic factor in vitro and in vivo
Kinet, Virginie; Castermans, Karolien; Blacher, Silvia ULg et al

Poster (2010, March)

Detailed reference viewed: 19 (0 ULg)
Full Text
See detailHYPERINSULINISM-HYPERAMMONEMIA: AN UNUSUAL CAUSE OF HYPOKETOTIC HYPOGLYCEMIA
HARVENGT, Julie ULg; LEBRETHON, Marie-Christine ULg; leroy, patricia et al

Poster (2010, March)

BACKGROUND Etiological diagnosis of hypoglycaemia in infancy is a complex process, requiring careful integration of detailed history, clinical and laboratory data. The causes of recurrent infant ... [more ▼]

BACKGROUND Etiological diagnosis of hypoglycaemia in infancy is a complex process, requiring careful integration of detailed history, clinical and laboratory data. The causes of recurrent infant hypoglycaemia include excessive insulin secretion, surreptitious insulin administration, deficiency of counter-regulatory hormones and inborn errors of metabolism. CLINICAL CASE A 10 month old girl was admitted at our emergency unit for generalized seizures without fever. Routine laboratory investigations were normal but blood glucose level was at 31 mg/dl. No ketone bodies were found in the urine. Past medical history revealed failure to thrive. A first seizure episode at 8 months of age during family’s holiday is reported. Tests performed in a foreign hospital revealed glycaemia at 36mg/dl. During her stay in our paediatric unit, several hypoglycaemias (31-45 mg/dl) were documented related to irritability as initial symptom of neuroglucopaenia. Detailed medical history revealed that fast tolerance was shorten with hypoglycaemia documented between one to three hours after eating. Clinical examination showed absence of hepatomegaly and failure to thrive: weight, -3SD; height, -2SD, and cranial circumference -2SD. At the time of hypoglycaemia, urinary tests revealed absence of ketonuria, that basically evokes hyperinsulinism or fatty acid oxidation deficiencies but these deficiencies were rapidly excluded by the very short fast state. Blood acylcarnitine profile was normal. Hyperinsulinism is defined by a ratio glycaemia/insulin below 4 with insulin values not necessary high. Since hyperinsulinism can not be excluded with only one blood measure, series of taking were performed during 24 hours. One of these tests was clearly positive with ratio equal to 2.3 (glycaemia at 41 mg/dl, insulin at 18µU/ml). For this patient, ammonemia was also tested with values ranged from 242 to 275 µg/dl (normal < 125) and the diagnosis of hyperinsulinism/hyperammoniemia (hi/ha) was made and confirmed by molecular analysis (mutation c.965G>A (p.R269H) in the GLUD1 gene). The treatment consists in this case by diazoxide and reduction of leucine intakes (< 200 mg of leucine/meal). DISCUSSION Differential diagnosis of hypoglycaemia with absence of ketonuria and absence of hepatomegaly include fatty acids β-oxidation defects, ketogenesis defects and hyperinsulinisms. Short fasting and post-prandial induced hypoglycaemia pointed to hyperinsulinism in our patient. Congenital hyperinsulinism includes KATP, glucokinase or glutamate deshydrogenase mutations. Hi/ha syndrome is due to activating mutations in the GLUD1 gene, coding for the glutamate dehydrogenase (GDH). Such mutations reduce the sensitivity of the enzyme to allosteric inhibition by GTP and consequently increase its sensitivity to allosteric activation by L-leucine. Hyperactivity of the GDH is responsible for over-oxidation of glutamate in β-pancreatic cells, increase of the ATP/ADP ratio and insulin release. Hyperactivity of GDH in liver is also responsible for hyperammonemia, which is usually mild and considered harmless for the brain. Nevertheless, recent studies have shown an increased epilepsy risk in cohorts of patients with hi/ha. CONCLUSION This case points out the importance of necessity for first investigations of infant documented case of hypoglycaemia. Patient history must focus on symptoms such as shorten fast tolerance periods and neurological symptoms of glucose deprivation. Blood samples should be taken at the time of hypoglycaemia and urine samples as soon as possible after the episode of hypoglycaemia. Initial normal insulin values do not allow the exclusion of the diagnosis of hyperinsulinism. [less ▲]

Detailed reference viewed: 63 (2 ULg)
Full Text
See detailESR evidence of superoxide anion, hydroxyl radical and singlet oxygen generation during photosensitization of PPME in HCT-116 cells
Quoilin, Caroline ULg; Guelluy, Pierre-Henri ULg; Grammenos, Angeliki ULg et al

Poster (2010, March)

Pyropheophorbide-a methyl ester (PPME), a derivative of chlorophyll a, is a second-generation photosensitizer and is studying largely in vitro for nearly a decade on cancerous cells. It has been ... [more ▼]

Pyropheophorbide-a methyl ester (PPME), a derivative of chlorophyll a, is a second-generation photosensitizer and is studying largely in vitro for nearly a decade on cancerous cells. It has been previously established on HCT-116 (human colon carcinoma cell line) that PPME is a molecule able to create apoptotic and necrotic death (Matroule et al). The cytotoxicity of PPME is presumed to be induced by reactive oxygen species (ROS) generated by the photoexcited molecule. Actually, to the best of our knowledge, no experimental evidence enables to confirm this supposition in an indubitable manner. Electron spin resonance (ESR) associated with spin trapping technique is a powerful method to detect, quantify and identify the ROS produced after photoactivation of PPME. Previous results indicate that PPME penetrates inside cells and localizes inside specific organelles (endothelial reticulum, Golgi apparatus and lysosome) (Matroule et al). The recent researches of Guelluy et al have also clearly demonstrated the presence of PPME inside mitochondrion. Consequently, ESR experiments were performed using an intracellular located spin trap, POBN (4-pyridyl 1-oxide-N-tert-butylnitrone), in order to detect in situ the ROS production. It has been shown that PPME is able to generate superoxide anions and hydroxyl radicals. Irradiation of the dye in HCT-116 cells in the presence of POBN spin trap and ethanol scavenger (2%, a non-toxic concentration) leads to the apparition of the ESR spectrum characteristics of POBN/ethoxy adduct. To assess the extent of contribution of ROS and to determine a possible reaction mechanism, competition experiments with specific quencher agents were carried out. Addition of catalase (CAT), a hydrogen peroxide quencher, or superoxide dismutase (SOD), a superoxide anion quencher, inhibits 30% of the signal. The parallel effect of SOD and CAT suggest that superoxide anion and hydrogen peroxide are involved in the generation of hydroxyl radicals via a Fenton reaction. This assertion is reinforced by the 20% reduction of signal intensity when adding desferroxamine, a Fe3+ chelator also implicated in Fenton reaction. Addition of DABCO, a quencher of singlet oxygen, to cells reduces 70% of the POBN/ethoxy adduct signal intensity. [less ▲]

Detailed reference viewed: 109 (1 ULg)
Full Text
See detailThe Hydrogen Electrode in Ionic Liquids: Acidity Measurements and Titrations
Robert, Thierry ULg; Malherbe, Cédric ULg; Magna, lionel et al

Poster (2010, March)

The acidity level in ILs containing acid was first determined using the Hammett acidity function (H0)1-2 in our laboratory. It was demonstrated that this attainable acidity, extending from -3 to -8, is ... [more ▼]

The acidity level in ILs containing acid was first determined using the Hammett acidity function (H0)1-2 in our laboratory. It was demonstrated that this attainable acidity, extending from -3 to -8, is exclusively depending of the nature of anion and follow the order: PF6 > BF4 > NTf2 > OTf. Nevertheless, the Hammett acidity function is an apparent function in this media and must then be corrected for. Consequently, in a second step, we tried to evaluate directly the proton activity from the determination of a potentiometric acidity function (R0) based on the extrathermodynamic Strehlow assumption.3 Therefore, the equilibrium potential of the H+/H2 couple was measured with an hydrogen electrode versus the ferricinium/ferrocene couple for which the potential is considered as independent of the solvent. [less ▲]

Detailed reference viewed: 155 (6 ULg)
Full Text
See detailQuantitative Evaluation of Imputities in Ionic Liquids
Robert, Thierry ULg; Olivier-Bourbigou, Hélène; Gilbert, Bernard ULg

Poster (2010, March)

Since several years, our laboratory is studying the acidity in ionic liquids and showed that very acidic levels can be reached in these media when a strong acid is added. These acidity levels were ... [more ▼]

Since several years, our laboratory is studying the acidity in ionic liquids and showed that very acidic levels can be reached in these media when a strong acid is added. These acidity levels were determined using Hammett acidity1 (spectroscopic method) and Strehlow acidity2 (potentiometric method) measurements. Considering the attainable acidity levels, it turns out that the purity of these ionic solvents is very critical because all impurities (i.e methylimidazole, water, acetone, chloride …) can act as (strong) bases. Therefore, it is imperative to quantify these impurities to obtain reproducible results. [less ▲]

Detailed reference viewed: 46 (6 ULg)
Full Text
See detailFaraday instability on a network
Delon, Giles ULg; Terwagne, Denis ULg; Adami, Nicolas ULg et al

Poster (2010, March)

Detailed reference viewed: 25 (10 ULg)
Full Text
See detailAn analytical method to determine the composition of cryolitic melts involved in the Hall-Heroult process by Raman spectroscopy
Malherbe, Cédric ULg; Gilbert, Bernard ULg

Poster (2010, March)

The Hall-Héroult process involves the metallic aluminium production from electroreduction of aluminium oxide in cryolitic melt (mostly composed of cryolite and aluminium fluoride) around 1000°C. In order ... [more ▼]

The Hall-Héroult process involves the metallic aluminium production from electroreduction of aluminium oxide in cryolitic melt (mostly composed of cryolite and aluminium fluoride) around 1000°C. In order to reduce the energy loss during this process, controlling the melt composition turns out to be critical. Unfortunately, no in situ analytical method allows measuring the melt composition yet. Since the Raman spectrum of the melt depends on both the cryolitic ratio (molar NaF/AlF3 ratio, CR) and the aluminium oxide content, our laboratory proposed in the past to apply Raman spectroscopy for direct melt composition determination by recording the spectrum from the top. However, experimental problems made the practical application difficult. Nowadays, the method is becoming more feasible because of new instrumental developments such as new sensitive CCD, fiber optics and new optical filters. [less ▲]

Detailed reference viewed: 59 (5 ULg)
Peer Reviewed
See detailInvolvement of miR-125b in in vitro and in vivo angiogenesis
Malvaux, Ludovic; Pendeville, Hélène; Sabatel, Céline et al

Poster (2010, March)

Detailed reference viewed: 11 (0 ULg)
See detailMultifractality in quantum maps
Martin, John ULg; Garcia-Mata, Ignacio; Giraud, Olivier et al

Poster (2010, March)

Detailed reference viewed: 11 (4 ULg)
Full Text
See detailAnalyse et évaluation des incidents médicamenteux au CHU de Liège
Bottari, Ludovic; Maesen, Didier ULg; Gerard, Xavier ULg et al

Poster (2010, February 27)

Detailed reference viewed: 92 (16 ULg)
Full Text
See detailEnquête sur les besoins et les attentes pour la pharmacie clinique au CHU de Liège
Gerard, Xavier ULg; Lerusse, Thomas ULg; Van Hees, Thierry ULg

Poster (2010, February 27)

Résultats d'un enquête auprès des médecins et des infirmiers chef d'unité sur la perception, les besoins et les attentes à propos de la pharmacie clinique au CHU de Liège.

Detailed reference viewed: 170 (22 ULg)
Full Text
See detailPoleward front of upwelling filaments generates subsurface anticyclonic eddies (FEDDY): a CAIBEX Project contribution
Sangrà, Pablo; Arístegui, Javier; Troupin, Charles ULg et al

Poster (2010, February 25)

Detailed reference viewed: 19 (0 ULg)
Full Text
See detailModeling and observation of an upwelling filament off Cape Ghir (NW Africa) during the CAIBEX survey
Troupin, Charles ULg; Sangrà, Pablo; Arístegui, Javier et al

Poster (2010, February 22)

Detailed reference viewed: 13 (0 ULg)
Full Text
Peer Reviewed
See detailEnzymatic process development for the extraction of ferulic acid from wheat bran
Giet, Jean-Michel ULg; Roiseux, O.; Blecker, Christophe ULg

Poster (2010, February 16)

Detailed reference viewed: 33 (5 ULg)
Full Text
See detailPretreatments and enzymatic hydrolysis of Miscanthus x giganteus for oligosaccharides production: delignification degree and characterisation of the hydrolysis products
Vanderghem, Caroline ULg; Jacquet, Nicolas ULg; Blecker, Christophe ULg et al

Poster (2010, February 04)

The aim of the present study is to compare two delignification methods (formic/acetic acid1 and soaking in aqueous ammonia) on Miscanthus x giganteus and to assess the suitability to produce cellobiose ... [more ▼]

The aim of the present study is to compare two delignification methods (formic/acetic acid1 and soaking in aqueous ammonia) on Miscanthus x giganteus and to assess the suitability to produce cellobiose and other oligosaccharides after enzymatic hydrolysis. Oligosaccharides have recently gotten attention for their health benefits. Two methods were compared in order to quantify lignin: the acid detergent lignin method (procedure of Van Soest most commonly employed by animal scientist and agronomists for analysis of forages) and the Klason lignin procedure. Lignin concentrations in raw material determined by both methods were different; Klason lignin value (23.5%) was greater than the acid detergent lignin concentration (12.9%). Possible reasons of these results will be discussed. Pretreatment by the formic/acid mixture showed a better deliginification rate compared to the soaking in aqueous ammonia method. Results were based on Klason lignin. Analysis of the structural carbohydrates revealed that untreated miscanthus was mainly composed of glucose and xylose. Extracted pulps by both delignification methods were hydrolysed by commercial cellulases and hemicellulases. A major challenge is the characterisation of complex mixtures of lignocellulosic hydrolysates. In this study, the hydrolysis products were separated and quantified by highperformance anion exchange chromatography with pulsed amperometric detection (HPAECPAD). This method was successfully applied to the quantitative analysis of monosaccharides (glucose and xylose) and disaccharides (cellobiose and xylobiose) formed by the enzymatic hydrolysis of pretreated miscanthus. The influence of the pretreatments on the oligosaccharides yields will be presented. [less ▲]

Detailed reference viewed: 52 (8 ULg)
Full Text
Peer Reviewed
See detailLife cycle environmental performance of using substitution fuels in cement production
Belboom, Sandra ULg; Halleux, Hubert; Léonard, Angélique ULg et al

Poster (2010, February 01)

Detailed reference viewed: 53 (14 ULg)
Full Text
Peer Reviewed
See detailA life-cycle assessment of injectable drug primary packaging : comparing the traditional process in glass vials with the new Closed Vial technology (polymer vials)
Belboom, Sandra ULg; Renzoni, Roberto ULg; Verjans, Benoît et al

Poster (2010, February 01)

This study based on the life cycle assessment methodology compares environmental impacts of two packaging alternatives used for injectable drugs: the traditional method based on glass vials and the new ... [more ▼]

This study based on the life cycle assessment methodology compares environmental impacts of two packaging alternatives used for injectable drugs: the traditional method based on glass vials and the new method developed by Aseptic Technologies based on polymer vials. [less ▲]

Detailed reference viewed: 68 (8 ULg)
Full Text
See detailTranscriptomic analysis of Arabidopsis roots during flowering
D'Aloia, Maria ULg; Tocquin, Pierre ULg; Périlleux, Claire ULg

Poster (2010, February)

Contribution of the root system to the flowering process remains poorly studied. Part of the problem resides in its difficult isolation from the substrate, especially on adult plants. Taking advantage of ... [more ▼]

Contribution of the root system to the flowering process remains poorly studied. Part of the problem resides in its difficult isolation from the substrate, especially on adult plants. Taking advantage of an hydroponic device that allows synchronous growth and flowering of Arabidopsis thaliana (Tocquin et al., 2003), we performed global transcript profiling of roots during induction of flowering by a single long day (LD). Results were validated by real-time RT-PCR, and the expression patterns of selected probes were further analyzed in shoots and roots. Some of the genes that were identified in the microarray experiment were already known to be involved in the photoperiodic pathway of flowering in Arabidopsis, and hence were activated in both roots and shoots during the LD. These genes include, for example, components of light signaling or circadian machinery (e.g. GIGANTEA). Other genes providing new insights into the control of flowering at the whole plant level will be presented. Tocquin et al., (2003). BMC Plant Biology, 3: 2. [less ▲]

Detailed reference viewed: 67 (15 ULg)
Full Text
See detailAN NMR INVESTIGATION OF THE ACTINIDE IONS AND THEIR COMPLEXES
Vidick, Geoffrey ULg; Bouslimani, Nouri; Desreux, Jean-François ULg

Poster (2010, January 28)

We currently use several advanced NMR techniques in order to fully characterize actinide ions and their complexes in water or in organic solvents. The dispersion of the longitudinal relaxation time T1 of ... [more ▼]

We currently use several advanced NMR techniques in order to fully characterize actinide ions and their complexes in water or in organic solvents. The dispersion of the longitudinal relaxation time T1 of solvent nuclei with the magnetic field (NMRD) yields information on the magnetic properties and on the dynamic behavior of paramagnetic species. 17O NMR allows the measurement of the water exchange times and 1H and 13C spectra yield information on the solution structures of the complexes and on the covalency of their coordination bonds. The application of NMR in actinide science will be illustrated with studies on the U, Np, Pu and Cm ions in different oxidation states and on their complexes. For instance, Cm3+ ion is the actinide analogue of Gd3+ but is not in a pure 8S state as indicated by much lower relaxation rates and much shortened electronic relaxation rates. In keeping with EPR studies1, Cm3+ does not have a perfectly spherical distribution of its unpaired electronic spins because of a much stronger spin-orbit coupling. Moreover, the Cm3+ relaxivity originates from three different processes: a dipolar coupling between the nuclear and electronic spins, a delocalization of unpaired electronic spins into the solvent orbitals (contact interaction) and a Curie contribution. Each process gives rise to an inflection point in the NMRD curves and the contact interaction reflects the partial covalency of the coordination bonds formed by Cm3+. A contact contribution is also observed in the NMR spectra of Cm3+ complexes. The sensitivity of NMR to the exact nature of the ground state of actinide ions is also illustrated by detailed studies on the U, Np and Pu ions in different oxidation states. For instance, a comparison of the NMRD curves of the 5f2 ions U4+, NpO2+ and PuO22+ indicates that the two dioxo cations have abnormally long electronic relaxation times. However, well-resolved 1H NMR spectra of their complexes can be obtained provided the solution species are sufficiently rigid. It will be shown that NpO2+ and PuO22+ induce dipolar paramagnetic shifts from which the solution structure can be deduced. [less ▲]

Detailed reference viewed: 30 (5 ULg)
See detailNOD2 interactome
Lecat, Aurore ULg; Di Valentin, Emmanuel ULg; Fillet, Marianne ULg et al

Poster (2010, January 28)

Detailed reference viewed: 31 (12 ULg)
See detailFunctional study of Arabidopsis thaliana ASF/SF2-like pre-mRNA SR splicing factors
Stankovic, Nancy ULg; Tillemans, Vinciane; Hanikenne, Marc et al

Poster (2010, January 26)

Detailed reference viewed: 20 (7 ULg)
See detailExpression of the metal homeostasis gene FRD3 in two Arabidopsis species
Charlier, Jean-Benoit ULg; Polese, Catherine; Motte, Patrick ULg et al

Poster (2010, January 26)

Detailed reference viewed: 32 (11 ULg)
See detailIdentification, characterization and expression profiling of the tomato gene TomLoxF
Mariutto, Martin ULg; Duby, Franceline ULg; Adam, Akram et al

Poster (2010, January 26)

Detailed reference viewed: 31 (10 ULg)
See detailFood and feeding of Limnothrissa miodon and Lamprichthys tanganicanus in Lake Kivu
Masilya, M Pascal; Isumbisho, Mwapu Pascal; Darchambeau, François ULg et al

Poster (2010, January 13)

Detailed reference viewed: 21 (1 ULg)
Full Text
See detailModelling total soil respiration in agricultural soils.
Buysse, Pauline ULg; Goffin, Stéphanie; Carnol, Monique ULg et al

Poster (2010, January 12)

Soil respiration is a process which results in CO2 release from the soil to the atmosphere. It comprises two main components. The first one is heterotrophic respiration: CO2 is produced by soil ... [more ▼]

Soil respiration is a process which results in CO2 release from the soil to the atmosphere. It comprises two main components. The first one is heterotrophic respiration: CO2 is produced by soil microorganisms while decomposing the substrate. The second one is autotrophic respiration in which CO2 originates from roots and rhizospheric organisms. All the CO2 is then transported to the surface by diffusion (see Goffin et al., this session). Many biotic and abiotic factors play a role in soil respiration, making this process complex to analyze and understand. Temperature often appears as the most important driving variable. Besides that, interest in the future CO2 emissions from agricultural soils has been growing. Indeed, these ecosystems are a major concern from environmental, economic and social points of view. In particular, the choice of cultural practices and residue management techniques has a strong influence on CO2 emissions from agricultural systems. This work aims at getting to a better understanding of soil respiration in agricultural soils. To reach this goal, many semi-mechanistic models have been previously developed at very different spatio-temporal scales. We intend to adapt such an existing model to crop soils, within a spatial scale of a cultivated field and an annual temporal scale. The model will be validated by using flux measurements carried out at three different crop sites situated in the Hesbaye region in Belgium (Lonzée) and in the South West of France (Lamasquère, Auradé). The study was focused first on soil heterotrophic respiration. Within this part, short term sensitivity of this component to temperature was studied by means of a laboratory incubation experiment. This one was performed with soil samples taken at the Lonzée site. Among the many interesting results we got, it showed a clear sensitivity of soil heterotrophic respiration to short term temperature changes. In parallel, the soil heterotrophic model was calibrated on soil chamber measurements taken at the Lonzée site (Belgium). Next steps in this part of the work will be to calibrate the model using the data from the French sites, and finally to validate the model on the three sites. Afterwards, an autotrophic respiration submodel will be implemented and the results compared to field measurements carried out at the three sites. A further development could consist in simulating agricultural practices to take their impacts on CO2 emissions from crops into account. [less ▲]

Detailed reference viewed: 67 (12 ULg)
Full Text
See detailCan an Electronic Nose Assess the Biomethanation Process?
Adam, Gilles ULg; Nicolas, Jacques ULg

Poster (2010, January 12)

Detailed reference viewed: 35 (11 ULg)
Full Text
See detailElectrical resistivity tomography and self-potential methods as a tool for fractured aquifer characterization and monitoring
Robert, Tanguy ULg; Nguyen, Frédéric ULg

Poster (2010, January 12)

Electrical resistivity tomography (ERT) and self-potential (SP) investigations are currently conducted in carboniferous limestones in Belgium. The aims of this study are (1) to characterize and (2) to ... [more ▼]

Electrical resistivity tomography (ERT) and self-potential (SP) investigations are currently conducted in carboniferous limestones in Belgium. The aims of this study are (1) to characterize and (2) to monitor the groundwater flow in fractured or karstic area and (3) to use these geophysical data as a help for groundwater flow model conceptualisation and inverse calibration. Large ERT profiles (320 meters) allow us to image the electrical resistivity distribution of the first 60 meters of the subsurface and to detect and characterize (in terms of direction, width and depth) some fractured and/or karstic zones expected to be less resistive. Data errors as well as indicators of resolution (resolution matrix, sensitivity matrix and DOI index) are analysed in order to calculate the depth of investigation of ERT and to avoid the misinterpretation of the resulting images. Self-potential measurements are performed along the electrical profiles and permit us to find some negative anomalies possibly related with groundwater preferential flow pathways. Since SP signals are related with the groundwater flow when taking into account the electrokinetic effect, we are able to estimate a first distribution of the water table along our profiles. These geophysical data concurrently with ‘ground truth’ geological and hydrogeological data give us a way to better understand the groundwater flow in limestone synclines of the Dinant Synclinorium geological structure. Still, further efforts are needed (1) to fully cover the syncline area and (2) to couple the SP, ERT and hydrogeological data through a more complex forward model of the electrokinetic effect of the self-potential method. [less ▲]

Detailed reference viewed: 114 (14 ULg)
See detailImage Appraisal Tools for Electrical Resistivity Tomography
Caterina, David ULg; Beaujean, Jean ULg; Robert, Tanguy ULg et al

Poster (2010, January 12)

Detailed reference viewed: 33 (21 ULg)
Full Text
See detailModelling of Forest Trees Autecology. An applied research at the Walloon Region scale (Belgium)
Ridremont, François ULg; Claessens, Hugues ULg; Lejeune, Philippe ULg et al

Poster (2010, January 12)

Three reasons have urged the Walloon Forest Administration (Walloon Public Service) on to solicit the help of forest researchers to bring practical responses to the adaptation of its current forests ... [more ▼]

Three reasons have urged the Walloon Forest Administration (Walloon Public Service) on to solicit the help of forest researchers to bring practical responses to the adaptation of its current forests management: (i) the progression of research in applied autecology, (ii) the development of software for the management and the analysis of georeferenced data (GIS technologies) and, (iii) the awareness of the potential negative impacts of climate change on forests. To answer to this request, this research aims to model the autecology of the main forest tree species at the Walloon Region scale (Beech, Oak, Norway Spruce, Douglas-fir and valuable broadleaves species). The results will be used to update current practical tools to assess the adequacy of forest tree species on sites, especially in the climate change context. The research is built into three main steps: • update the autecology knowledge for the targeted forest tree species through a state of the art; • compile and create different ecological parameters that can explain the major part of trees growth such as climatic, topographic, geologic, edaphic and phytosociological data gathered from forest plots or geodatabases. In the context of climate change, a particular attention will be brought on bioclimatic and soil moisture conditions because of their narrow link with the potential risk of trees ecophysiological stress; • model tree species reaction to environmental conditions with tree growth indicators. Three types of indicators with different spatio-temporal scales are foreseen: stand site index (30-50 years), periodic diameter growth (5-10 years) and tree-ring growth (1-3 years). The use of these three scales is justified by the interest presented by their cross-validations which are necessary for an accurate extrapolation of results to the entire region. Results should indicate the tree species behaviour, especially towards stress conditions. The integration of climatic data, provided by global climate models based on IPCC's climate scenarios, in autecological models could be used to assess the behaviour of forest stands in future climate conditions. From those results, we expect to identify and assess accurately the risky “sites-species pairs” to avoid in the context of a sustainable silviculture. Finally, results will be used to provide autecological synthesis and practical tools to help forest managers and foresters to identify the best “site-species pairs” (tree-site adequacy maps, sites catalogue and computer platform). [less ▲]

Detailed reference viewed: 148 (43 ULg)
Full Text
Peer Reviewed
See detailADDICTION AU MMORPG : QUAND LE REEL EST SOUS L’EMPRISE DU VIRTUEL
Bataille, Stéphanie; Triffaux, Jean-Marc ULg

Poster (2010, January)

Detailed reference viewed: 200 (6 ULg)
Peer Reviewed
See detailHarmonia axyridis (Pallas) secondary metabolites quantification in relation with aposematism : Part II : Pyrazine quantification
Fischer, Christophe ULg; Heuskin, Stéphanie ULg; Marlet, Christelle ULg et al

Poster (2010, January)

The main objective of this study is to investigate the presence of links between chemical defences and warning signals presented by Harmonia axyridis (Pallas), the multicoloured Asian ladybird (Insects ... [more ▼]

The main objective of this study is to investigate the presence of links between chemical defences and warning signals presented by Harmonia axyridis (Pallas), the multicoloured Asian ladybird (Insects: Coleoptera: Coccinellidae). This second part describes an original quantification method for 2-isopropyl-3-methoxypyrazine (IPMP) by active sampling on thermally desorbed adsorbent (TD) coupled with GC-MS analysis. This highly odorous compound is supposed to be implicated in intra- and interspecific communication. In order to allow harmonine quantification (a defence alkaloid, see Part 1), this method avoid any hemolymph loses by the ladybird (Coccinellids can emit hemolymph when stressed). This method is non-lethal and applicable on one single insect. The quantification method has been validated from 37,5pg to 10 000 pg per adsorbent cartridge. On this range, there is no breakthrough and desorption is complete (>99.4%). At the LOQ (37.5pg/cartridge), the bias is of 20%, but rapidly decreased to less than 5% on the rest of the validated range (100 to 10 000 pg/cartridge). According to AOAC (2006) norm, this method is repeatable but not reproducible. The IPMP emission rate following a stress has been quantified on 80 H. axyridis grouped in four classes on basis of the morph type and the elytra hue. Males and females emission rates did not significantly differ. The mean emission rate is of 707 pg/4h with an extremely high standard deviation of 1766pg/4h due to a great individual variability and a strongly asymmetric distribution of the results. These results and those of the harmonine and colour analysis have been statistically analyzed in order to show potential correlations between these factors. It seems that elytra colour is linked with the insect IPMP emission rate. Individuals with a melanic red colour presented IPMP emission rate significantly lower than other studied colours. The harmonine content does not seem linked to the pyrazine emission rate. [less ▲]

Detailed reference viewed: 139 (7 ULg)
Full Text
See detailAnalysis of aldehydes relaesed by rice flour using sorbent adsorption and thermal desorption - gas chromatography/mass spectrometry: Development and validation
Mertens, Cécile ULg; Marlet, Christelle ULg; Blecker, Christophe ULg et al

Poster (2010, January)

Odor is an essential characteristic and a quality marker in baby foodstuff, like a partially hydrolyzed and pregelatinized rice flour. The rice flour study by active sampling and TD-GC/MS highlighted the ... [more ▼]

Odor is an essential characteristic and a quality marker in baby foodstuff, like a partially hydrolyzed and pregelatinized rice flour. The rice flour study by active sampling and TD-GC/MS highlighted the presence of three aldehydes: Hexanal, Octanal, Nonanal. These compounds are known to be caused by lipid oxidation, one of the major alteration reactions in food. The Method was developed and valited on a large range for the three aldehydes. It was then applied to the rice fllour to determine if it can be used to follow the effect of ageing on the aldehydes production. [less ▲]

Detailed reference viewed: 63 (17 ULg)
Peer Reviewed
See detailHarmonia axyridis (Pallas) secondary metabolites quantification in relation with aposematism : Part I : Harmonine quantification
Fischer, Christophe ULg; Heuskin, Stéphanie ULg; Laurent, Pascal ULg et al

Poster (2010, January)

These last few years, the multicoloured Asian ladybird, Harmonia axyridis Pallas (Insects: Coleoptera: Coccinellidae), an invasive species, has swiftly spread out in Europe. This aposematic and highly ... [more ▼]

These last few years, the multicoloured Asian ladybird, Harmonia axyridis Pallas (Insects: Coleoptera: Coccinellidae), an invasive species, has swiftly spread out in Europe. This aposematic and highly polymorphic insect is problematic in several ways. It seems to outcompete native coccinellid species; they can group on fruits in vineyards and spoil wine when crushed with grapes; they can aggregate by hundreds in houses to winter. This study aims to investigate the relations between the chemical defences of H. axyridis and warning signals expressed by this bug. To achieve this goal, two original quantification methods of H. axyridis secondary metabolites have been undertaken. The first one allows Fast-GC quantifying harmonine, its main defence alkaloid. The other one permits to determine its emission rate of 2-isopropyl-3-methoxypyrazine, a highly odorous compound probably involved in the communication between individuals and in the aposematism of this insect. This last point will be detailed in another poster. Firstly, a method of extraction, acetylation and purification of harmonine from H. axyridis has been devised to obtain a calibration standard because this molecule is not commercially available. The identity of the extracted compound has been confirmed by mass spectrometry and multidimensional NMR. The GC purity of this N,N-diacetylharmonine is of 100%. During the experiments, its stability in acetone solution at 4°C has been verified. Using this purified molecule, an original method of harmonine quantification has been developed by fast gas chromatography and validated using accuracy profile. The method has been validated for concentrations ranging from 28µg/ml to more than 264µg/ml, with a maximal error risk of 20%. From about 100µg/ml, peaks symmetry decreased, but did not influence the quantification. That accuracy profile validation has been compared with a more classical validation using AOAC (2006) norm, which confirmed the first validation. This method allows quantifying harmonine in one single insect. Harmonine has been quantified in 80 H. axyridis divided into four groups of at least 15 individuals on basis of the morph type and the elytra hue. Males and females harmonine contents did not significantly differ. The mean harmonine content was of 106.6µg/individual with a standard deviation of 80.2µg/individual. The results distribution obtained was not normal and a strong variability between individuals was observed, which explains the high standard deviation. These results and those of the pyrazine and colour analysis have been statistically analyzed in order to show potential correlations between these factors. It would appear that elytra colour is linked with the insect harmonine content. Individuals with a non-melanic orange colour presented harmonine content significantly higher than other studied colours. The harmonine content does not seem linked to the pyrazine emission rate. [less ▲]

Detailed reference viewed: 235 (24 ULg)
Full Text
See detailLow detection HPLC – DAD analysis of aldehydes and ketones in indoor air : Development and validation by accuracy profile
Marlet, Christelle ULg; Haesen, Charlotte ULg; Lognay, Georges ULg

Poster (2010, January)

Aliphatic aldehydes and ketones like formaldehyde are reactive volatile compounds and common indoor pollutants. The main sources are tobacco smoke, combustion gases, painting and materials. Theses ... [more ▼]

Aliphatic aldehydes and ketones like formaldehyde are reactive volatile compounds and common indoor pollutants. The main sources are tobacco smoke, combustion gases, painting and materials. Theses compounds also arise from the reaction between unsaturated compounds and oxidative agents. The toxic potential of formaldehyde and other aliphatic/aromatic carbonyl compounds requires the determination of even low amounts of these compounds in indoor air. The present method for indoor monitoring uses adsorption at 2,4-dinitrophenylhydrazine (DNPH)-coated sorbents followed by HPLC-UV/DAD analysis of the extract. Detection limits of 0.1μg/m3 were reached by this method which is sufficient for indoor air monitoring. Three DNPH-derivatives could be separated well on a RP-Amide column followed by UV/DAD-detection at 360 nm. Recovery rates of 70-100 % were determined using liquid spiking method. Validation strategy was intentionally oriented towards the ease of use in routine and the liability of the method rather than extreme performances. For that, the validation by accuracy profile was chosen. The accuracy profile, based on the concept of total error (bias + standard deviation), allows to correctly conclude about the validity of a procedure and thus, guarantees that a known proportion of future results obtained with the method will be included within acceptance limits. For the three tested compounds, formaldehyde, acetaldehyde and acetone, the accuracy profile gave the guarantee that at least 95% of the future results obtained with the validated method will be within the ±25% acceptance limits over the whole concentration range defined. The HPLC parameters were also determinated. The performance of the method was finally evaluated by the analysis of indoor air from new timber frame construction. [less ▲]

Detailed reference viewed: 188 (12 ULg)
Full Text
Peer Reviewed
See detailA fast gas chromatographic method for the study of semiochemical slow release formulations
Heuskin, Stéphanie ULg; Lorge, Stéphanie; Leroy, Pascal ULg et al

Poster (2010, January)

Detailed reference viewed: 32 (7 ULg)
Full Text
See detailIDENTIFICATION OF METABOLITES IN A HUMAN PLASMA STANDARD REFERENCE MATERIAL BY MULTIPLE GC/MS APPROACHES
Eppe, Gauthier ULg; Benner, Bruce; White, Edward et al

Poster (2010, January)

Detailed reference viewed: 27 (1 ULg)
Full Text
See detailComparison of two drainage flow situations on a gentle forested slope
Heinesch, Bernard ULg; Yernaux, Michel ULg; Aubinet, Marc ULg

Poster (2010)

Drainage flows generated on a gentle slope in stable conditions were analysed at the forested site of Vielsalm (Belgium). Two distinct situations were encountered, one corresponding to vertical ... [more ▼]

Drainage flows generated on a gentle slope in stable conditions were analysed at the forested site of Vielsalm (Belgium). Two distinct situations were encountered, one corresponding to vertical convergence, characterised by a negative vertical velocity at the canopy top, the other corresponding to an equilibrium situation without any vertical movement. The causes of these two distinct flow patterns were analysed. Moreover, combined measurements of vertical velocity above the canopy and horizontal velocity divergence below the canopy were found to comply with the continuity equation: an acceleration of the horizontal flow was indeed observed in the trunk-space in convergence situations while not in equilibrium conditions. These measurements combined with those of the horizontal [CO2] gradient below the canopy were found to met the dilution hypothesis suggested by Aubinet et al.(2003): the horizontal [CO2] gradient was negative in convergence situations while slightly positive in equilibrium conditions. The existence of such patterns allows us to confirm the coherence of advection observations made at the site and help to better understand the mechanisms responsible of night flux exchanges at work in stable conditions in complex terrains. Nevertheless, difficulties were met when trying to obtain reliable estimates of the advection transport terms. The estimation of the vertical velocity in the trunk-space obtained by using the divergence measurements refuted the hypothesis of linearity of the vertical profile of vertical velocity, assumption usually used when computing vertical advection. This problem resulted in a great uncertainty on vertical advection which did not allowed to improve the night-flux estimation by adding advection terms to the turbulent flux and the storage. [less ▲]

Detailed reference viewed: 34 (1 ULg)