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See detailOptimization of an Haematococcus pluvialis medium by a Genetic Algorithm-based strategy
Fratamico, Anthony ULg; Tocquin, Pierre ULg; Franck, Fabrice ULg

Poster (2012, June 14)

The successful use of living organisms for the production of biomass or metabolites requires a careful control and optimization over growing conditions. However the range of interacting parameters makes ... [more ▼]

The successful use of living organisms for the production of biomass or metabolites requires a careful control and optimization over growing conditions. However the range of interacting parameters makes full optimization difficult and time-consuming. In this context, Genetic Algorithm-based (GA) methods emerge as promising strategies for optimization of biotechnological processes. However, the potential of GA in the microalgae field remains, today, poorly explored. As a proof-of-concept, we evaluated how GA could be applied for the optimization of a medium for high yield photoautotrophic growth of Haematoccocus pluvialis. [less ▲]

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See detailOptimization of BaZrO3 sintering by control of the initial powder size distribution; a factorial design statistical analysis
Guillaume, Bernard ULg; Boschini, Frédéric ULg; Garcia-Cano, I. et al

in Journal of the European Ceramic Society (2005), 25(16), 3593-3604

A factorial design statistical analysis has been conducted in order to obtain the optimum conditions in the solid state sintering process of barium zirconate bulk materials, optimum with respect to ... [more ▼]

A factorial design statistical analysis has been conducted in order to obtain the optimum conditions in the solid state sintering process of barium zirconate bulk materials, optimum with respect to density, closed and open porosities. The optimized heat treatment permits to sinter a 99% dense barium zirconate sample at 1650 degrees C during only 2 h. When the temperature is higher than 1650 degrees C or when the heating time is longer than 2 h, a decrease in density is observed. (c) 2004 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 35 (1 ULg)
See detailOptimization of bioconversion of vanillin into vanillic acid by Pseudomonas fluorescens strain BTP9
Bare, G.; Delaunois, V.; Perrin, L. et al

Poster (1993, July)

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See detailOptimization of biodegradable microparticles for tissue engineering
Drozdova, M.; Demina, T.; Sevrin, Chantal ULg et al

Poster (2013, June 19)

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See detailOptimization of biodegradable microparticles loaded with thrombin receptor agonist peptide (TRAP-6) for tissue engineering
Drozdova, M; Privalova, A; Demina, T et al

Conference (2012)

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See detailOptimization of Biomass-Fuelled Combined Cooling, Heating and Power (CCHP) Systems Integrated with Subcritical or Transcritical Organic Rankine Cycles (ORCs)
Maraver, Daniel; Quoilin, Sylvain ULg; Royo, Javier

in Entropy (2014), 16(5), 2433-2453

This work is focused on the thermodynamic optimization of Organic Rankine Cycles (ORCs), coupled with absorption or adsorption cooling units, for combined cooling heating and power (CCHP) generation from ... [more ▼]

This work is focused on the thermodynamic optimization of Organic Rankine Cycles (ORCs), coupled with absorption or adsorption cooling units, for combined cooling heating and power (CCHP) generation from biomass combustion. Results were obtained by modelling with the main aim of providing optimization guidelines for the operating conditions of these types of systems, specifically the subcritical or transcritical ORC, when integrated in a CCHP system to supply typical heating and cooling demands in the tertiary sector. The thermodynamic approach was complemented, to avoid its possible limitations, by the technological constraints of the expander, the heat exchangers and the pump of the ORC. The working fluids considered are: n-pentane, n-heptane, octamethyltrisiloxane, toluene and dodecamethylcyclohexasiloxane. In addition, the energy and environmental performance of the different optimal CCHP plants was investigated. The optimal plant from the energy and environmental point of view is the one integrated by a toluene recuperative ORC, although it is limited to a development with a turbine type expander. Also, the trigeneration plant could be developed in an energy and environmental efficient way with an n-pentane recuperative ORC and a volumetric type expander. [less ▲]

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See detailOptimization of biosurfactant lipopeptide production from Bacillus subtilis S499 by Plackett-Burman design
Jacques, P.; Hbid, C.; Destain, Jacqueline ULg et al

in Applied Biochemistry and Biotechnology (1999), 77-9

Bacillus subtilis S499 is well-known for its ability to produce two families of surfactant lipopeptides: Iturin A and Surfactin S1. Fermentation optimization for this strain was performed to amplify the ... [more ▼]

Bacillus subtilis S499 is well-known for its ability to produce two families of surfactant lipopeptides: Iturin A and Surfactin S1. Fermentation optimization for this strain was performed to amplify the surfactant production. Ten active variables were analyzed by two successive Plackett-Burman designs, consisting respectively of 12 and 16 experiments to give an optimized medium. The amount of biosurfactant lipopeptides in the supernatant of a culture carried out in this optimized medium was about five times higher than that obtained in nonoptimized rich medium. The analysis of the surfactant molecules produced in such optimized conditions has revealed the presence of a third family of lipopeptides: the fengycins. The time-dependent production of these three families of molecules in bioreactors showed that surfactin S1 is produced during the exponential phase and iturin A and fengycins during the stationary phase. [less ▲]

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See detailOptimization of biosurfactant lipopeptide production from Bacillus subtilis S499 by plackett-burman design
Jacques, Ph.; Hbid, Ch.; Razafindralambo, Hary ULg et al

Poster (1998, May)

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See detailOptimization of blocked designs in fMRI studies
Maus, Bärbel ULg; van Breukelen, G. J. P.; Goebel, R. et al

in Psychometrika (2010), 75(2), 373390

Blocked designs in functional magnetic resonance imaging (fMRI) are useful to localize functional brain areas. A blocked design consists of different blocks of trials of the same stimulus type and is ... [more ▼]

Blocked designs in functional magnetic resonance imaging (fMRI) are useful to localize functional brain areas. A blocked design consists of different blocks of trials of the same stimulus type and is characterized by three factors: the length of blocks, i.e., number of trials per blocks, the ordering of task and rest blocks, and the time between trials within one block. Optimal design theory was applied to find the optimal combination of these three design factors. Furthermore, different error structures were used within a general linear model for the analysis of fMRI data, and the maximin criterion was applied to find designs which are robust against misspecification of model parameters. [less ▲]

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See detailOptimization of blocked designs in fMRI studies
Maus, Bärbel ULg; Van Breukelen, G.J.P; Goebel, R. et al

in NeuroImage (2009), 47(Supplement 1), 125

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See detailOptimization of calcium phosphate scaffold-cell combinations using an integrative model based approach
Carlier, Aurélie ULg; Chai, Yoke Chin; Theys, Tina et al

in International Conference on Tissue Engineering (ECCOMAS) - proceedings (2011, June 03)

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See detailOptimization of computed tomography (CT) arthrography of hip for the visualization of cartilage: an in vitro study
SIMONI, Paolo ULg; Leyder, Pierre-Philippe; Albert, Adelin ULg et al

in Skeletal Radiology (2013), 43(2), 169-178

OBJECTIVE: We sought to optimize the kilovoltage, tube current, and the radiation dose of computed tomographic arthrography of the hip joint using in vitro methods. MATERIALS AND METHODS: A phantom was ... [more ▼]

OBJECTIVE: We sought to optimize the kilovoltage, tube current, and the radiation dose of computed tomographic arthrography of the hip joint using in vitro methods. MATERIALS AND METHODS: A phantom was prepared using a left femoral head harvested from a patient undergoing total hip arthroplasty and packed in a condom filled with iodinated contrast. The right hip joint of a cadaver was also injected with iodinated contrast. The phantom and the cadaver were scanned using different values of peak kilovoltage (kVp) and tube current (milliamp seconds, mAs). Three different regions of interest (ROI) were drawn in the cartilage, subchondral bone plate, and intraarticular contrast. The attenuation values, contrast/noise ratio (CNR), and effective dose were calculated. Two independent observers classified the quality of the contrast-cartilage interface and the cartilage-subchondral bone plate interface as (1) diagnostic quality or (2) nondiagnostic quality. RESULTS: Contrast, cartilage, and subchondral bone plate attenuation values decreased at higher kVp. CNR increased with both kVp and mAs. The qualitative analysis showed that in both phantom and cadaver, at 120 kVp and 50 mAs, the contrast-cartilage and cartilage-subchondral bone plate interfaces were of diagnostic quality, with an effective dose decreased to 0.5 MSv. CONCLUSIONS: The absolute effective dose is not directly related to the quality of images but to the specific combination of kVp and mAs used for image acquisition. The combination of 120 kVp and 50 mAs can be suggested to decrease the dose without adversely affect the visibility of cartilage and subchondral bone plate. [less ▲]

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See detailOptimization of conditions for the glycosyltransferase activity of penicillin-binding protein 1a from Thermotoga maritima.
Offant, Julien; Terrak, Mohammed ULg; Derouaux, Adeline ULg et al

in FEBS Journal (2010), 277(20), 4290-8

Cell wall biosynthesis is a key target for antibacterial drugs. The major constituent of the bacterial wall, peptidoglycan, is a netlike polymer responsible for the size and shape of the cell and for ... [more ▼]

Cell wall biosynthesis is a key target for antibacterial drugs. The major constituent of the bacterial wall, peptidoglycan, is a netlike polymer responsible for the size and shape of the cell and for resisting osmotic pressure. It consists of glycan chains of repeating disaccharide units cross-linked through short peptide chains. Peptidoglycan assembly is catalyzed by the periplasmic domain of bifunctional class A penicillin-binding proteins. Cross-linking of the peptide chains is catalyzed by their transpeptidase module, which can be inhibited by the most widely used antibiotics, the beta-lactams. In contrast, no drug in clinical use inhibits the polymerization of the glycan chains, catalyzed by their glycosyltransferase module, although it is an obvious target. We report here the purification of the ectodomain of the class A penicillin-binding protein 1a from Thermotoga maritima (Tm-1a*), expressed recombinantly in Escherichia coli. A detergent screen showed that detergents with shorter aliphatic chains were better solubilizers. Cyclohexyl-hexyl-beta-D-maltoside-purified Tm-1a* was found to be monomeric and to have improved thermal stability. A miniaturized, multiwell continuous fluorescence assay of the glycosyltransferase activity was used to screen for optimal reaction conditions. Tm-1a* was active as a glycosyltransferase, catalyzing the formation of glycan chains up to 16 disaccharide units long. Our results emphasize the importance of the detergent in preparing a stable monomeric ectodomain of a class A penicillin-binding protein. Our assay could be used to screen collections of compounds for inhibitors of peptidoglycan glycosyltransferases that could serve as the basis for the development of novel antibiotics. [less ▲]

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See detailOptimization of cricket breeding production system for human food in Ratanakiri province (Cambodia)
Caparros Megido, Rudy ULg; Alabi, Taofic ULg; Nieus, Clément et al

Poster (2014)

Despite many natural resources, Cambodia is considered as a relatively poor country with a Gross National Income per capita averaging about 880 USD in 2012. Annâdya project in the Ratanakiri province ... [more ▼]

Despite many natural resources, Cambodia is considered as a relatively poor country with a Gross National Income per capita averaging about 880 USD in 2012. Annâdya project in the Ratanakiri province (Cambodia) aims to improve the food security and nutrition of smallholder households by introducing and facilitating the adoption of productive and environmentally sustainable agricultural technologies. The main purpose of this work was to optimize a cheap cricket breeding production system for local farmers to contribute to the reduction of protein deficiency and to create new source of incomes. Cricket development, Teleogryllus testaceus (Walker), was compared between seven diets composed of different ratio of aerial parts of taro, young cassava leaves, young cashew leaves, brown rice flour (with or without the addition of banana slices) and between the traditionally used chicken feed diet. Cricket mortality was relatively low on all diets (<10 %) excepted on the two cashew-based diets where mortality achieves 90 %. Mean adult body mass of the cricket was significantly higher on control diet (chicken feed) and on the two cassava-based diet (80% of cassava leave flour, 20% of brown rice with or without banana slices) than on the other diets (F = 20.87, P<0.001). The nutritional analyzes of the seven diets shows that the ideal diet should contain 19% protein, 5-6% fat, and a percentage of carbohydrates as high as possible. While the cricket mass body gain seems to be proportional to the carbohydrate content of the diet, the use of older cassava leaves, more rich in carbohydrates than the younger ones, is an interesting solution to substitute relatively expensive brown rice and banana slices also consumed by local population. In the future, consideration should be given to the adjustment of cassava leave maturity in function of the cricket growth stage as it is already done with chicken feed in Thai cricket farms. [less ▲]

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See detailOptimization of drug-cyclodextrin complexation reaction by a static supercritical carbon dioxide method
Brion, Michael; Nizet, Dominique; Piel, Géraldine ULg et al

Conference (2007)

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See detailOptimization of dynamic embedded, Water based surface heat (and cold) emitting system for buildings.
Thomas, Sébastien ULg; Franck, Pierre-Yves ULg; Andre, Philippe ULg

Conference (2009, October)

This paper presents the heat flow model and the experimental test bench developed to optimize a new kind of heating floor. In the first part of the text is described the new kind of high reactivity ... [more ▼]

This paper presents the heat flow model and the experimental test bench developed to optimize a new kind of heating floor. In the first part of the text is described the new kind of high reactivity emitting device for building heating and cooling. A second part illustrates the numerical model developed to evaluate the device efficiency. Finally experimental test bench implementation and results are presented. Both computational and experimental results support the use of colder water in comparison to other heating devices. This implies energy savings for building heating. [less ▲]

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See detailOptimization of encoding specificity for the diagnosis of early AD: The RI-48 task
Adam, Stéphane ULg; Van der Linden, Martial ULg; Ivanoiu, A. et al

in Journal of Clinical & Experimental Neuropsychology (2007), 29(5), 477-487

The aim of this study was to evaluate the discriminant validity of the RI-48 test, a shorter French version of the Category Cued Recall portion of the Double Memory Test developed initially by Buschke and ... [more ▼]

The aim of this study was to evaluate the discriminant validity of the RI-48 test, a shorter French version of the Category Cued Recall portion of the Double Memory Test developed initially by Buschke and colleagues (1997), in the diagnosis of mild and very mild Alzheimer disease (AD). The distinctive feature of the RI-48 task is that encoding specificity was increased by adding an immediate cued recall stage at the encoding phase. The results show that the RI-48 task seems to be well adapted to the clinical context and to have good psychometric properties, in particular a lack of a ceiling effect. Moreover, this task appears to be especially well suited for the diagnosis of both mild and very mild AD (sensitivity of 93% and 83.8%). From a more theoretical point of view, this study confirms the importance of optimizing the encoding specificity for the diagnosis of very mild AD, since the more encoding specificity is accentuated, the more discriminating power is increased for the diagnosis of very mild AD. [less ▲]

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See detailOptimization of enzymatic extraction of ferulic acid from wheat bran, using response surface methodology, and characterization of the resulting fractions
Barberousse, Helene; Kamoun, Amel; Chaabouni, Moncef et al

in Journal of the Science of Food and Agriculture (2009), 89(10), 1634-1641

BACKGROUND: The agro-industries generate thousands of tons of by-products, such as bran or pulps, each year. They are, at best, used for cattle feeding. Through biocracking, this biomass may constitute a ... [more ▼]

BACKGROUND: The agro-industries generate thousands of tons of by-products, such as bran or pulps, each year. They are, at best, used for cattle feeding. Through biocracking, this biomass may constitute a renewable source for various molecules of interest for the industry. For instance, ferulic acid, a compound showing antioxidant ability, is found in abundance in cereal bran. Its release depends mainly on the breaking of its ester linkage to other constitutive elements of the cell wall, such as arabinoxylans. Response surface methodology was used to evaluate the effects of ferulic acid esterase (FAE) and xylanase activities, as well as incubation time and temperature, on ferulic acid extraction yield from wheat bran. Under optimized conditions, the composition of the hydrolysate and of residual bran were compared to native bran. RESULTS: Experiments carried out under the predicted optimal conditions (FAE amount, 27 U g(-1); xylanase amount, 304 U g(-1); incubation time, 2 h; and temperature, 65 degrees C) led to an extraction yield of 52.8%, agreeing with the expected value (51.0%). The crude ferulic acid fraction was purified with Amberlite XAD16, leading to a final concentration of 125 mu g mL(-1) of ferulic acid in ethanol. The antioxidant capacity of this purified fraction was evaluated by the DPPH. scavenging method: it exhibited better efficiency (EC50 = 10.6 mu mol L-1 in ferulic acid) than the ferulic acid standard (EC50 = 13.7 mu mol L-1). CONCLUSION: These results confirm the potential of wheat bran valorization in the field of natural antioxidant extraction, possibly viable in an industrial scheme. (C) 2009 Society of Chemical Industry [less ▲]

Detailed reference viewed: 102 (10 ULg)