Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
See detailImprovement of data quality for Diffusion Kurtosis Imaging and application to clinical neurological research
André, Elodie ULg

Doctoral thesis (2014)

Understanding human brain function and dysfunction is one of the major challenges of our century. One of the most popular methods to achieve this goal is in vivo magnetic resonance imaging. In particular ... [more ▼]

Understanding human brain function and dysfunction is one of the major challenges of our century. One of the most popular methods to achieve this goal is in vivo magnetic resonance imaging. In particular, diffusion-weighted (DW) imaging has become a standard tool to non-invasively study white matter structure in vivo. The main contributions of this work can be divided in two parts. The first part deals with the development of pre-processing methods to improve image quality and the accuracy of diffusion tensor and diffusion kurtosis-derived parameters. First, we describe and evaluate a novel method to correct data misalignment due to subject motion. Using an iterative model-based ap- proach, individual diffusion images are realigned to their own theoretical pair, rather than to the unweighted image. A recently developed advanced measure of tensor distance was used as a stopping criterion. The accuracy of the method is tested via a simulated diffusion tensor imaging data set. We have shown here that our procedure is a reliable and efficient way to correct subject motion during DW acquisitions, and that with a proper acquisition setup, it performs better than standard coregistration procedures. Next, we studied the influence of noise in diffusion kurtosis imaging. Two noise correction approaches are proposed and applied to a pool of 25 sub- jects to evaluate inter-subject variability and the impact of noise correc- tion. Additionally, data were acquired on a single subject with different head positions within the coil and different acquisition scheme to evaluate the impact of noise correction on within-subject variability. Results show a strong impact of noise correction on the estimated mean kurtosis, while the estimation of fractional anisotropy and mean diffusivity were less affected. Both within- and between-subject signal-to-noise (SNR) related variability of the mean kurtosis estimate is considerably reduced after correction for the noise bias, leading to more accurate and reproducible measures. In this work, we have proposed a straightforward method that improves the accu- racy of diffusion kurtosis metrics. Diffusion kurtosis imaging acquisitions at higher spatial resolution are made possible, which increases the chances to make valuable inferences in group analysis.The second part of this thesis deals with a clinical application of these meth- ods. A large group of patients with early-stage Parkinson’s disease was in- vestigated with diffusion kurtosis imaging and compared with a group of age- and sex-matched healthy volunteers using voxel-based analysis. Kur- tosis metrics show more sensitivity to white matter changes than standard diffusion metrics. Significant differences were found in posterior cerebral areas as well as subcortical regions like the putamen, and are therefore promising results. [less ▲]

Detailed reference viewed: 126 (20 ULg)
Full Text
See detailImprovement of defect detection in shearography by using Principal Component Analysis
Vandenrijt, Jean-François ULg; Lièvre, Nicolas; Georges, Marc ULg

in Proceedings of Conference on Interferometry XVII: Techniques and Analysis (2014, August)

Detailed reference viewed: 38 (14 ULg)
Full Text
Peer Reviewed
See detailImprovement Of Enzymatic-Synthesis Yields Of Flavor Acetates - The Example Of The Isoamyl Acetate
Razafindralambo, Hary ULg; Blecker, Christophe ULg; Lognay, Georges ULg et al

in Biotechnology Letters (1994), 16(3), 247-250

Isoamyl acetate synthesis was chosen as a model to improve flavour acetate yields by optimising the enzymatic reaction. Alcohol:acid molar ratio, temperature, water content and amount of enzyme effects ... [more ▼]

Isoamyl acetate synthesis was chosen as a model to improve flavour acetate yields by optimising the enzymatic reaction. Alcohol:acid molar ratio, temperature, water content and amount of enzyme effects were analyzed. The optimum values were respectively 4, 45 degrees C, 0,1% (w/v) and 0,5 g. In these conditions, the synthesis yield reached 80% after 24 h of reaction and was found 15 times greater than those already reported in the literature. [less ▲]

Detailed reference viewed: 87 (41 ULg)
Peer Reviewed
See detailImprovement of fed batch mass culture for g linolenic biosynthesis by Tetrahymena rostrata (Protozoa).
Gosselin, Y.; Lognay, Georges ULg; Thonart, Philippe ULg

in Biotechnology Letters (1989), 11(6), 423-426

Detailed reference viewed: 16 (5 ULg)
Full Text
Peer Reviewed
See detailImprovement of fermentative biohydrogen production by Clostridium butyricum CWBI1009 in sequenced-batch, horizontal fixed bed and biodisc-like anaerobic reactors with biomass retention
Hiligsmann, Serge ULg; Beckers, Laurent; Masset, Julien et al

in International Journal of Hydrogen Energy (2014), 39

A horizontal tubular fixed bed bioreactor (HFBR) and an anaerobic biodisc-like reactor (AnBDR) were designed to both fix Clostridium biomass and enable rapid transfer of the hydrogen produced to gas phase ... [more ▼]

A horizontal tubular fixed bed bioreactor (HFBR) and an anaerobic biodisc-like reactor (AnBDR) were designed to both fix Clostridium biomass and enable rapid transfer of the hydrogen produced to gas phase in order to decrease the strong effect of H2 partial pressure and H2 supersaturation on the performances of Clostridium strains. The highest H2 production rate (703 mL H2/L.h) and yield (302 mL/g glucose consumed i.e. 2.4 mol/mol) with the pure culture were recorded in the AnBDR with 300 mL culture medium (total volume 2.3 L) at pH 5.2 and a glucose loading rate of 2.87 g/L.h. These results are about 2.3 and 1.3-fold higher than those achieved in the same bioreactor with 500 mL liquid medium and with the same glucose consumption rate. Therefore, our experimentations and a short review of the literature reported in this paper emphasize the relevance of performing bioreactors with high L/G transfer. [less ▲]

Detailed reference viewed: 52 (9 ULg)
See detailImprovement of foaming properties of whey protein products by enzymatic hydrolysis of the associated fat fraction
Blecker, Christophe ULg; Lamberti, I.; Sensidoni, A. et al

Conference (1996, March)

Detailed reference viewed: 21 (2 ULg)
Full Text
Peer Reviewed
See detailImprovement of Gc-Rich Template Amplification by Inverse Pcr
Moreau, Alain; Duez, Colette ULg; Dusart, Jean

in BioTechniques (1994), 17(2), 232-4

Detailed reference viewed: 30 (4 ULg)
Full Text
Peer Reviewed
See detailImprovement of He ion induced SiGe layer relaxation by a thin Si:C layer
Buca, D.; Trinkaus, H.; Holländer, B. et al

Conference (2008)

Detailed reference viewed: 9 (0 ULg)
See detailImprovement of inland navigation in developping countries: the training center of Palembang (Sumatra, Indonesia), an example of transfer of technology through education
Marchal, Jean ULg

in Bulletin des Séances de l’Académie Royale des Sciences d’Outre-Mer = Mededelingen der Zittingen van de Koninklijke Academie voor Overzeese Wetenschappen (1997), Nouvelle Série 42(4)(1er trimestre), 10

Detailed reference viewed: 25 (2 ULg)
Peer Reviewed
See detailImprovement of insulin-induced glucose disposal in obese patients with NIDDM after 1-wk treatment with d-fenfluramine.
Scheen, André ULg; Paolisso, G.; Salvatore, T. et al

in Diabetes Care (1991), 14(4), 325-32

OBJECTIVE: To study the short-term effects of the serotoninergic anorectic drug d-fenfluramine on insulin-induced glucose disposal. RESEARCH DESIGN AND METHODS: A randomized double-blind placebo ... [more ▼]

OBJECTIVE: To study the short-term effects of the serotoninergic anorectic drug d-fenfluramine on insulin-induced glucose disposal. RESEARCH DESIGN AND METHODS: A randomized double-blind placebo-controlled crossover trial with 1-wk treatment periods (2 x 15 mg/day d-fenfluramine) was conducted. Twenty obese subjects, 10 with normal oral glucose tolerance and 10 with non-insulin-dependent diabetes mellitus (NIDDM), were all treated with a weight-maintaining diet. Euglycemic-hyperinsulinemic glucose clamps with measurement of glucose kinetics with D-[3-3H]glucose were performed at either two (patients without NIDDM, 0.05 and 0.10 U.kg-1.h-1) or three (patients with NIDDM, 0.05, 0.10, and 0.50 U.kg-1.h-1) insulin delivery rates. RESULTS: In the nondiabetic subjects, no significant changes in any metabolic or hormonal parameter were measured in the basal state or during the clamp despite a slight reduction in body weight (-1.2 +/- 0.5 kg, P less than 0.05). In the diabetic patients, no significant changes in body weight or basal plasma insulin levels were observed, but fasting blood glucose levels (8.0 +/- 0.8 vs. 9.4 +/- 1.1 mM, P less than 0.005) and plasma free fatty acid concentrations (1150 +/- 227 vs. 1640 +/- 184 microM, P less than 0.05) were significantly reduced after d-fenfluramine compared with placebo. During the clamp, insulin metabolic clearance rate (MCR) was similar after both placebo and d-fenfluramine; endogenous (hepatic) glucose production was similarly and almost completely suppressed, whereas glucose disposal was remarkably enhanced after d-fenfluramine (average increase of glucose MCR 35 +/- 12%, P less than 0.02). CONCLUSIONS: Whatever the mechanism(s) involved, a 1-wk treatment with d-fenfluramine induces better blood glucose control and improves insulin sensitivity in obese patients with NIDDM independent of significant weight reduction; this last effect is not present in obese subjects with normal oral glucose tolerance. [less ▲]

Detailed reference viewed: 15 (1 ULg)
Peer Reviewed
See detailImprovement Of Inulin Hydrolysis Yeast-Cell Reactor By Mutants Selection
Thonart, Philippe ULg; Weber, Dominique ULg; Rikir, R.

in Applied Biochemistry and Biotechnology (1988), 17

Detailed reference viewed: 4 (0 ULg)
Full Text
Peer Reviewed
See detailImprovement Of Lactic Cell Production
Desmons, S.; Krhouz, H.; Evrard, P. et al

in Applied Biochemistry and Biotechnology (1998), 70-2

Detailed reference viewed: 15 (2 ULg)
See detailImprovement of lactic cell production.
Desmons, S.; Khrouz, H.; Evrard, P. et al

Poster (1997, May)

Detailed reference viewed: 5 (0 ULg)
Full Text
Peer Reviewed
See detailImprovement Of Lipase Production From Yarrowia Lipolytica
Destain, Jacqueline ULg; Weber, D.; Thonart, Philippe ULg

in Biotechnology Letters (1997), 19(2),

Detailed reference viewed: 11 (0 ULg)
Full Text
Peer Reviewed
See detailImprovement of lupin seed valorisation by the pig with the addition of alpha-galactosidase in the feed and the choice of a suited variety.
Froidmont, E.; Wathelet, Bernard ULg; Beckers, Yves ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2005), 9(4), 225-235

Three experiments were conducted to assess whether an a-galactosidase supplement improved the utilisation of lupin seeds by growing and finishing pigs and to determine the best lupin variety in presence ... [more ▼]

Three experiments were conducted to assess whether an a-galactosidase supplement improved the utilisation of lupin seeds by growing and finishing pigs and to determine the best lupin variety in presence of a-galactosidase. In experiment 1, three iso-nitrogen (iso-N) and iso-net energy (iso-NE) diets containing 15% of soybean meal (SBM diet) or 20% of lupin seeds (Lupinus albus var. Arès), with or without an a-galactosidase supplement (‘lupin’ and ‘lupin + a-gal’ diets, respectively), were ingested by 12 pigs fitted with a caecal canula, following a completely randomized experimental design. The ileal digestibility of a-galactosides tended to increase with the lupin + a-gal diet. Nitrogen retention of pigs eating the SBM diet was similar to that of those fed with the lupin + a-gal diet and higher than that observed for pigs given the lupin diet. The results suggested that a-galactosides are the main anti-nutritional factors in lupin seeds for pigs. The same diets were investigated in a production trial (experiment 2) involving 48 pigs with a live weight of between 30 and 105 kg. The fattening period was similar for the SBM and lupin + a-gal diets (107 d) and longer for the lupin diet (123 d). With the lupin diet there was a lower average daily gain (ADG, -16%) and a higher food conversion ratio (FCR, + 8%) than with the two other diets. The backfat of pigs fed with lupin-based diets contained fewer polyunsaturated fatty acids (PUFA) and had a lower w6/w3 ratio. In experiment 3, three iso-N and iso-NE diets containing different varieties of lupin (Lupinus albus cv Lublanc and Amiga; Lupinus angustifolius cv Boltensia) and an a-galactosidase supplement were investigated in 12 pigs fitted with a caecal canula, as in Exp. 1. The results showed that the digestible protein supply by the Boltensia diet was higher than in the others. However, the Boltensia variety led to a higher urinary N excretion than the Lublanc variety. The results obtained with Amiga were intermediate. Consequently, the utilisation of ingested and digested proteins was relatively high with the Lublanc diet, intermediate with the Amiga diet and low with the Boltensia diet. The results suggested that the Lublanc variety was better adapted for pig feed that contained an a-galactosidase supplement. [less ▲]

Detailed reference viewed: 90 (23 ULg)
Peer Reviewed
See detailImprovement of metal dispersion in Pd/SiO2 cogelled xerogel catalysts
Lambert, Stéphanie ULg; Polard, Jean-François; Ferauche, Fabrice et al

Poster (2004)

Detailed reference viewed: 6 (3 ULg)
Full Text
Peer Reviewed
See detailImprovement of metal dispersion in Pd/SiO2 cogelled xerogel catalysts for 1,2-dichloroethane hydrodechlorination
Lambert, Stéphanie ULg; Polard, Jean-François; Pirard, Jean-Paul ULg et al

in Applied Catalysis B : Environmental (2004), 50

The study of the influence of synthesis operating variables (nature and concentration of complexing silane, palladium percentage, temperatures of gelling, aging and vacuum drying of xerogels, molar ratio ... [more ▼]

The study of the influence of synthesis operating variables (nature and concentration of complexing silane, palladium percentage, temperatures of gelling, aging and vacuum drying of xerogels, molar ratio between the complexing silane and palladium, molar concentration of ammonia solution, and use of tetramethylammonium hydroxide as base instead of NH3) allows improving metal dispersion in Pd/SiO2 cogelled xerogel catalysts. The use of 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS) or 3-(2-aminoethylamino)propyltriethoxysilane (EDAES) to complex palladium in an ethanolic solution containing tetraethoxy si lane (TEOS) and an ammonia solution of 0.54 mol/l allows obtaining a Pd/SiO2 xerogel catalyst with a mean metal particle diameter of 2.4 nm located inside silica particles. Indeed, complexes Pd(EDA(E)S)(x)(n+) induce a nucleation mechanism because of their higher reactivity compared to the network-reagent (TEOS). Although metal particles are located inside the silica particles, their complete accessibility, via the micropore network, has been shown. 1,2-dichloroethane hydrodechlorination over Pd/SiO2 catalysts mainly produces ethane and the specific hydrodechlorination rate per gram of palladium increases proportionally with palladium dispersion. Hydrodechlorination over Pd/SiO2 cogelled xerogel catalysts is a structure insensitive reaction with regard to the ensemble size concept. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 88 (8 ULg)
See detailImprovement of Mucor lipase production by mutant selection.
Roblain, D.; Destain, Jacqueline ULg; Thonart, Philippe ULg

Poster (1988, July)

Detailed reference viewed: 6 (0 ULg)