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See detailOptimization of Matrix Conditions for the Control of MALDI In-Source Decay of Permethylated Glycans.
Smargiasso, Nicolas ULg; De Pauw, Edwin ULg

in Analytical Chemistry (2010), sous presee

Due to its fastness and its easiness to use, MALDI-MS is currently an analytical tool widely used in glycomic applications. However, the MALDI ionization process could result in the so-called "in-source ... [more ▼]

Due to its fastness and its easiness to use, MALDI-MS is currently an analytical tool widely used in glycomic applications. However, the MALDI ionization process could result in the so-called "in-source decay", or ISD, of analytes, leading to complex spectra. On the other hand, ISD opens the possibility to perform pseudo-MS(3) experiments. This phenomenon must therefore be controlled in order to be used on demand as a supplementary tool for the analysis of permethylated glycans by MALDI mass spectrometry. For this purpose, several matrices were tested and MALDI imaging was used to determine optimal conditions promoting or, inversely, avoiding ISD of permethylated glycans. 2,5-DHB was shown to be a versatile matrix allowing one to induce or prevent ISD according to the location of laser shots. Inversely, it was shown that 9-aminoacridine forms homogeneous spots and avoids completely ISD. This matrix would therefore be suitable for automatic analysis. [less ▲]

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See detailOptimization of mechatronic systems: application to a modern car equipped with a semi-active suspension
Duysinx, Pierre ULg; Bruls, Olivier ULg; collard, Jean-François et al

in Herskowitz, José (Ed.) Proceedings of the 6th World Congress of Structural and Multidisciplinary Optimization (WCSMO6) (2005, May)

The research aims at developing a global mechatronic approach to model, simulate and optimize complex industrial applications. The approach is illustrated with the simulation and the optimization of a ... [more ▼]

The research aims at developing a global mechatronic approach to model, simulate and optimize complex industrial applications. The approach is illustrated with the simulation and the optimization of a modern car (an Audi A6) equipped with a controlled semi-active suspension. An optimization procedure is used to find the best sub-system parameters in order to improve the comfort of the passengers while preserving the car ride and handling performances. Two different modeling and optimization approaches are used and compared. The first one is realized in the MATLAB-SIMULINK environment and is based on a symbolic multibody model of the chassis while the hydraulic actuators, and the controller are integrated using S-functions. Optimization is also carried out in MATLAB using algorithms available in MATLAB libraries, especially a genetic algorithm (GA). On the other hand, the second approach relies on a multibody model based on the Finite Element method whereas the optimization can be realized with an industrial open optimization tool. [less ▲]

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See detailOptimization of micro-HPLC peak focusing for the detection and quantification of low hepcidin concentrations.
Mansion, François ULg; Chiap, Patrice ULg; Houbart, Virginie ULg et al

in Journal of Separation Science (2011), 34(15), 1820-1827

Micro-high-performance liquid chromatography is a miniaturized, economic and ecological chromatographic system allowing the use of reduced size chromatographic columns. Coupled with electrospray ... [more ▼]

Micro-high-performance liquid chromatography is a miniaturized, economic and ecological chromatographic system allowing the use of reduced size chromatographic columns. Coupled with electrospray ionization tandem mass spectrometry, this technique can be used to detect and quantify low concentrations of peptides. In this study, hepcidin was used as the model compound and analysed using octadecylsilica stationary phase by means of a gradient elution mode at a flow rate of 4 muL/min. Several parameters were studied to optimize peak focusing. Using the methodology of experimental design, the mobile-phase gradient conditions and the sample composition were optimized in order to maximize the sensitivity and minimize retention time. Stability of the target peptide in solution was also demonstrated. [less ▲]

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See detailThe optimization of microsatellite genotyping and genetic sexing of non-invasively collected polar bear tissue: Implications for monitoring and census.
Harris, Christopher; Van Coeverden De Groot, Peter; Kamookak, L et al

Conference (2012, April)

The monitoring of Polar Bears in Canada has been completed largely through management unit (MU) wide capture-mark-recapture (CMR) surveys. While this data is very useful at the time of collection, these ... [more ▼]

The monitoring of Polar Bears in Canada has been completed largely through management unit (MU) wide capture-mark-recapture (CMR) surveys. While this data is very useful at the time of collection, these surveys are expensive and take time to plan and execute; cannot be feasibly executed across the polar bear range at intervals that reflect the expected rapid environmental changes in the Arctic; and are disdained by the Inuit as being invasive. As part of recent efforts to explore less expensive and non-invasive methods to monitor polar bears (see Wong et al & Van Coevderden de Groot et al this conference) we are evaluating genetic information obtained from non-invasively collected polar bear tissue. In this work we report on the genetic data obtained from non-invasively collected harisnags recovered from sampling stations erected between May-June 2006-2009 in M’Clintock Channel, Nunavut. Across the 4 years 344 hair snags were collected; following Paetkau (2004) we optimized 6 microsatellite loci to reliably amplify polar bear DNA from this tissue and we modified the procedure of Pages et al (2009) to reliably genetically sex these tissues. Our estimates for two common errors with this type of tissue across all loci – allelic dropout (0.026) and false allele (0.03) - were both less than p =.05. This suggests these errors are not going to significantly affect the accuracy of the consensus genotypes collected from these data. Using consensus genotypes from relevant hairsnags, we posit a minimum of 59 (max 82) unique bears entered our sampling stations. Of these, 24% were female, 64% were male, and 12% could not be sexed. We resampled 2 bears in 2006, 1 in 2007, 0 bears in 2008 and 14 bears in 2009 – the 2009 value reflects significantly increased sampling effort in 2009. Five bears were re-sampled between the non-invasive surveys in 2006-2009. When comparing our data to a subset of cubs and subadults captured during the Taylor et al. (2006) CMR survey of M’Clintock Channel (MU), we found 6 genotype matches. Our sampling stations may have a male bias as the sex ratio from the 1998-2000 CMR study was 42.1% ♂ (Taylor et al 2006) vs. 64% ♂ (this study). We cannot accurately determine the age bias (but see Wong et al this conference). Genetic data from Polar bear faecal samples may provide an unbiased sex and age sample of polar bears in any MU. Any data from these samples will help refine hairsnag derived MKNA estimate of polar bears from any MU. Here we report on our efforts to genotype and genetically sex 95 faecals we have collected from M’Clintock Channel from 2006-2009. Finally, we discuss the implications of these findings, results from other noninvasive work (Wong et al & Van Coevderden de Groot et al this conference) and ongoing/proposed work in the context of i) a non-invasive Inuit-based polar bear activity and health survey, and ii) a more rigorous census method which may allow more precise adjustments of harvest levels than currently possible using infrequently collected CMR data only. [less ▲]

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See detailOptimization of monopile offshore wind structures
Thiry, Arnaud; Rigo, Philippe ULg; Buldgen, Loïc ULg et al

in Marstruct (2011)

ABSTRACT: As industrialization is essential for large-scale offshore wind deployment, a computerized methodology to optimize the scantling of monopile steel structures has been developed using a genetic ... [more ▼]

ABSTRACT: As industrialization is essential for large-scale offshore wind deployment, a computerized methodology to optimize the scantling of monopile steel structures has been developed using a genetic alg rithm. The objective functions of this tool are minimization of the structure weight and production costs. The constraints implemented are mainly related to structural stability under extreme loads, resonance check of the wind turbine support and fatigue strength at welded connections between shells and stiffeners. This optimiz tion should be invoked at the preliminary stage of the offshore project in order to assess the impacts of the structure design on the fabrication and installation costs. [less ▲]

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See detailOptimization of multibody systems and their structural components
Bruls, Olivier ULg; Lemaire, Etienne ULg; Duysinx, Pierre ULg et al

in Blajer, W.; Arczewski, K.; Fraczek, J. (Eds.) et al Multibody Dynamics: Computational Methods and Applications (2011)

This work addresses the optimization of flexible multibody systems based on the dynamic response of the full system with large amplitude motions and elastic deflections. The simulation model involves a ... [more ▼]

This work addresses the optimization of flexible multibody systems based on the dynamic response of the full system with large amplitude motions and elastic deflections. The simulation model involves a nonlinear finite element formulation, a time integration scheme and a sensitivity analysis and it can be efficiently exploited in an optimization loop. In particular, the paper focuses on the topology optimization of structural components embedded in multibody systems. Generally, topology optimization techniques consider that the structural component is isolated from the rest of the mechanism and use simplified quasi-static load cases to mimic the complex loadings in service. In contrast, we show that an optimization directly based on the dynamic response of the flexible multibody system leads to a more integrated approach. The method is applied to truss structural components. Each truss is represented by a separate structural universe of beams with a topology design variable attached to each one. A SIMP model (or a variant of the power law) is used to penalize intermediate densities. The optimization formulation is stated as the minimization of the mean compliance over a time period or as the minimization of the mean tip deflection during a given trajectory, subject to a volume constraint. In order to illustrate the benefits of the integrated design approach, the case of a two degrees-of-freedom robot arm is developed. [less ▲]

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See detailOptimization of murine CD8+ cytotoxic T-lymphocyte responses to pseudorabies virus
Depierreux, C.; Graff, I.; Lancelot, V. et al

in Journal of Immunological Methods (1997), 203

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See detailOptimization of Parabolic Arches Subjected to Distributed Loads
Latteur, Pierre ULg; Samyn, Philippe

(1999, September)

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See detailOptimization of particle packing by analytical and computer simulation approaches
He, Huan ULg; Stroeven, Piet; Stroeven, Martijn et al

in Computers and Concrete (2012), 9(2), 119-131

Optimum packing of aggregate is an important aspect of mixture design, since porosity may be reduced and strength improved. It may also cause a reduction in paste content and is thus of economic relevance ... [more ▼]

Optimum packing of aggregate is an important aspect of mixture design, since porosity may be reduced and strength improved. It may also cause a reduction in paste content and is thus of economic relevance too. Several mathematic packing models have been developed in the literature for optimization of mixture design. However in this study, numerical simulation will be used as the main tool for this purpose. A basic, simple theoretical model is used for approximate assessment of mixture optimization. Calculation and simulation will start from a bimodal mixture that is based on the mono-sized packing experiences. Tri-modal and multi-sized particle packing will then be discussed to find the optimum mixture. This study will demonstrate that computer simulation is a good alternative for mixture design and optimization when appropriate particle shapes are selected. Although primarily focusing on aggregate, optimization of blends of Portland cement and mineral admixtures could basically be approached in a similar way. [less ▲]

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See detailOptimization of PCR Conditions to Amplify Microsatellite Loci in Grapevine (Vitis vinifera L.) Genomic DNA
Ghaffari, Sana; Hasnaoui, Nejib ULg; Ferchichi, Ali

in Revue des Régions Arides (2009), 24

A total of three different primer pairs were optimized for polymerase chain reaction (PCR) to amplify microsatellite loci in total genomic DNA of grapevine (Vitis vinifera L.). Different concentrations of ... [more ▼]

A total of three different primer pairs were optimized for polymerase chain reaction (PCR) to amplify microsatellite loci in total genomic DNA of grapevine (Vitis vinifera L.). Different concentrations of MgCl2, DNA and different regimes of annealing temperature were optimized. For all the primer pairs, 2.5 mM MgCl2 concentration was found optimum. For DNA concentration, 100 ng in the final reaction volume was suitable for good amplification. Annealing temperatures 56°C, 61°C and 58°C were found optimum to amplify with primer pairs VVMD5, scu04vv and VMC8E6, respectively. The other reagents used in PCR and temperature regimes (denaturation and extension temperature) were kept constant. The protocol has been successfully applied producing scorable and clear amplicons in all cultivars studied. These loci can be used to evaluate the genetic variability and cultivar relatedness in autochthonous Vitis vinifera cultivars from Tunisia. [less ▲]

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See detailOptimization of pectin extraction from lemon by-product with acidified date juice using response surface methodology
Masmoudi, Manel; Besbes, Souhail; Chaabouni, Moncef et al

in Carbohydrate Polymers (2008), 74(2), 185-192

Response surface methodology was used to optimize pectin recovery from lemon by-product using an acidified date juice as extraction solution. When enriched in pectin, this latter can be useful for ... [more ▼]

Response surface methodology was used to optimize pectin recovery from lemon by-product using an acidified date juice as extraction solution. When enriched in pectin, this latter can be useful for preparation of date-lemon jelly. The effects of three parameters namely temperature, pH and extraction time, on pectin extraction were Studied. The fitted mathematical model allowed Lis to plot response surfaces as well as isoresponse curves and to determine optimal extraction conditions. Results clearly indicated that the temperature was the main factor influencing the pectin yield which increased with temperature and time or decreasing pH. The selected optimal conditions were: temperature 84.34 degrees C extraction time 3 h 34 min and pH 2.8. These conditions yielded about 11.21%, of pectin versus 10.89% for the predicted value. (C) 2008 Elsevier Ltd. All rights reserved. [less ▲]

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See detailOptimization of poly(2-(dimethylamino)ethyl methacrylate)-co-poly(ethyleneglycol)/DNA complexes designed for cell transfection
Grandfils, Christian ULg; Emonds-Alt, J.

in Minerva Biotecnologica (2005), 17(4), 237-243

Cell transfection relies upon the delivery of genomic material within cells in order to express selected DNA sequences. Non-viral gene delivery systems are preferable over viral vectors for several ... [more ▼]

Cell transfection relies upon the delivery of genomic material within cells in order to express selected DNA sequences. Non-viral gene delivery systems are preferable over viral vectors for several reasons: biosafety, low immunogenicity, higher loading capacity, and easiness of production. Their major drawbacks actually are their limited efficiency in vivo compared to viruses, their cytotoxicity and the fact that they are rapidly cleared up from the bloodstream. The aim of our study was to better characterize the physico-chemical behavior of the polycations based on poly(2-(dimethylamino)ethyl methacrylate)-co-poly(ethyleneglycol) and to control the formulation step to produce the polyelectrolyte complexes. [less ▲]

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See detailOptimization of polymerase chain reaction for detection of Clostridium botulinum type C and D in bovine samples
Prevot, V.; Tweepenninckx, F.; Van Nerom, E. et al

in Zoonoses and Public Health (2007), 54(8), 320-327

Botulism is a rare but serious paralytic illness caused by a nerve toxin that is produced by the bacterium Clostridium botulinum. The economic, medical and alimentary consequences can be catastrophic in ... [more ▼]

Botulism is a rare but serious paralytic illness caused by a nerve toxin that is produced by the bacterium Clostridium botulinum. The economic, medical and alimentary consequences can be catastrophic in case of an epizooty. A polymerase chain reaction (PCR)-based assay was developed for the detection of C. botulinum toxigenic strains type C and D in bovine samples. This assay has proved to be less expensive, faster and simpler to use than the mouse bioassay, the current reference method for diagnosis of C. botulinum toxigenic strains. Three pairs of primers were designed, one for global detection of C. botulinum types C and D (primer pair Y), and two strain-specific pairs specifically designed for types C (primer pair VC) and D (primer pair VD). The PCR amplification conditions were optimized and evaluated on 13 bovine and two duck samples that had been previously tested by the mouse bioassay. In order to assess the impact of sample treatment, both DNA extracted from crude samples and three different enrichment broths (TYG, CMM, CMM followed by TYG) were tested. A 100% sensitivity was observed when samples were enriched for 5 days in CMM followed by 1 day in TYG broth. False-negative results were encountered when C. botulinum was screened for in crude samples. These findings indicate that the current PCR is a reliable method for the detection of C. botulinum toxigenic strains type C and D in bovine samples but only after proper enrichment in CMM and TYG broth. [less ▲]

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See detailOptimization of POP analysis in small sample amounts.
L'Homme, Benjamin ULg; Focant, Jean-François ULg

Conference (2012, October)

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See detailOptimization of Production and Preliminary Characterization of New Exopolysaccharides from Gluconacetobacter hansenii LMG1524
Valepyn, Emmanuel ULg; Berezina, Nathalie; Paquot, Michel ULg

in Advances in Microbiology (2012), 2(4), 488-496

The influence of different carbon and nitrogen sources, of ethanol concentration, the optimal pH, temperature and me-dium composition were evaluated on extracellular polysaccharides (EPS) synthesis and ... [more ▼]

The influence of different carbon and nitrogen sources, of ethanol concentration, the optimal pH, temperature and me-dium composition were evaluated on extracellular polysaccharides (EPS) synthesis and bacterial growth of Gluconace-tobacter hansenii LMG1524, and preliminary characterization of EPS was investigated. The highest EPS yields were obtained using glycerol and ammonium sulphate as carbon and nitrogen sources, respectively. The increase of ethanol concentration in the medium did not influence the EPS synthesis but reduced the bacterial growth. The optimum tem-perature and pH for polysaccharides production were respectively 25 °C and 5; whereas for cell growth were respec-tively 30 °C and 4. The optimal culture medium composition was determined as follows : 10 g/L sucrose, 0.892 g/L (NH4)2SO4, 0.34 g/L NaNO3, 3 mL acetic acid, 1.5 g/L KH2PO4, 1.5 g/L K2HPO4 and 0.6 g/L MgSO4. The polysaccha-rides produced were of 14 and 10 polymerization degrees (DP) and constituted mainly of glucose, galactose and man-nose, in relative percent of 36.36, 33.94 and 22.42, respectively. [less ▲]

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See detailOPTIMIZATION OF RAPESEED MEAL USE FOR FATTENING BULLS
Paquay, R.; Mandiki, S.; Bister, J.-L. et al

Poster (1999)

Two experiments were conducted in order to optimize the incorporation of rapeseed meal (RPM) in diets for growing and fattening of bulls. In a first experiment, the effects of 20% of a low glucosinolate ... [more ▼]

Two experiments were conducted in order to optimize the incorporation of rapeseed meal (RPM) in diets for growing and fattening of bulls. In a first experiment, the effects of 20% of a low glucosinolate (LG) RPM (3.14 mmoles/g DM of concentrate) were studied. In a second experiment, various proportions (0, 10, 20, 34%) of an LG- industrial RPM were tested in order to determine the optimal level in diet of young bulls. Thirty six young Belgian White Blue bulls were used. In the two experiments, large amount of industrial RPM (20 - 34%) did not reduce animal performance whatever the parameter considered (liveweight, daily weight gains, food intake, feed conversion, carcass weight, dressing percentages). Values did not also vary with the level of LG-RPM in the diet. Any effects were observed on the thyroid weight and the size of thyroid follicles. The secretion of thyroid hormones was not affected by RPM except for a decrease (P < 0.05) in the production of thyroxin by thyroid tissue decreased (P < 0.05) with 34% in the diet in Experiment 2. Results concerning plasma testosterone and cortisol contrasted between the two experiments with negative effects or no influence of LG-RPM. It was concluded that levels 20 ≤ A < 34% of double 00 – RPM in diet may be used for fattening bulls but investigations are still needed to outline the long-term effects on steroids and reproductive performance [less ▲]

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See detailOptimization of recombinant human erythropoietin therapy after allogeneic hematopoietic stem cell transplantation.
Baron, Frédéric ULg; Sautois, Brieuc ULg; Baudoux, Etienne ULg et al

in Experimental hematology (2002), 30(6), 546-54

OBJECTIVE: Allogeneic hematopoietic stem cell transplantation (HSCT) is associated with prolonged anemia caused by defective erythropoietin (Epo) production. We enrolled 34 recipients of an allogeneic ... [more ▼]

OBJECTIVE: Allogeneic hematopoietic stem cell transplantation (HSCT) is associated with prolonged anemia caused by defective erythropoietin (Epo) production. We enrolled 34 recipients of an allogeneic HSCT in three consecutive trials to determine the optimal utilization of recombinant human erythropoietin (rhEpo) therapy in this setting. MATERIALS AND METHODS: In the first trial (n = 7), rhEpo 1400 U/kg/week was given from day 1 until a hemoglobin (Hb) level of 10 g/dL was achieved, for a maximum of 60 days. In the second trial, rhEpo 500 U/kg/week was given to achieve Hb levels of 13 to 14 g/dL in 13 anemic patients with fatigue 56 to 1440 days after transplant. In the third trial, rhEpo was scheduled to start on day 35 in 14 patients at a dose of 500 U/kg/week with the aim of achieving Hb levels of 13 to 14 g/dL. RESULTS: In trial 1, erythroid recovery to 1% reticulocytes and red blood cell transfusion independence were faster, but the number of transfusions was not reduced compared to 10 controls. Responses were brisk in trial 2, with transfusion independence achieved after a median of 1 week in 12 of 13 patients, and 2-g Hb increments or Hb values of 11, 12, and 13 g/dL after 6, 7, 10, and 10 weeks, respectively. Transfusions were significantly reduced in the first month of rhEpo therapy. In trial 3, transfusion independence was obtained after a median of 1 week in 13 of 14 patients, and 2-g Hb increments or Hb values of 11, 12, and 13 g/dL after 3, 4, 6, and 8 weeks, respectively. Transfusions rates were considerably reduced compared to the previous month in the same patients or compared to controls undergoing peripheral blood or marrow transplant without rhEpo. CONCLUSIONS: Anemia after allogeneic HSCT is exquisitely sensitive to rhEpo. The benefit is minimal when it is given early post-transplant, as used in all trials to date. However, the rate of major response is greater than 90% when rhEpo is started after day 35. These data provide the basis on which to conduct a prospective, randomized, placebo-controlled trial of rhEpo therapy after allogeneic HSCT. [less ▲]

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See detailOptimization of recombinant root-secreted IgGs production in Arabidopsis thaliana by screening cell wall mutants
Boulanger, Benoit ULg; Périlleux, Claire ULg; Tocquin, Pierre ULg

Poster (2012, April 18)

The production of complex heterologous proteins (e.g. monoclonal antibodies, mAbs) in plants has several advantages animal based systems such as low cost, scalability and limited risk of contamination by ... [more ▼]

The production of complex heterologous proteins (e.g. monoclonal antibodies, mAbs) in plants has several advantages animal based systems such as low cost, scalability and limited risk of contamination by human pathogens. mAbs are glycoproteins that require to be targeted to the plant secretory pathway in order to be properly folded and matured. They are ultimately delivered in the cell wall and are expected to be freely released in the extracellular space and the external medium, which would greatly simplify downstream processing. However, a significant part of plant produced and secreted mAbs remains bound to the cell wall, therefore hindering recovery. In this study, we evaluated the extra-cellular release of root-secreted proteins of wild-type plants and cell wall mutants of Arabidopsis thaliana. Recovered protein were either analyzed by SDS-PAGE for full proteome profiling or by gelatin zymography to reveal the activity of cell wall-bound proteases. The production, secretion and release of recombinant IgG will be eventually studied in transgenic hairy-roots generated from selected mutants. [less ▲]

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