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See detailEvaluation of two commercial solid-phase microextraction fibres for the analysis of target aroma compounds in cooked beef meat
Machiels, D.; Istasse, Louis ULg

in Talanta (2003), 61(4), 529-537

The aroma profile of cooked beef meat has been investigated by solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS). Out of more than 200 volatile compounds, 36 ... [more ▼]

The aroma profile of cooked beef meat has been investigated by solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS). Out of more than 200 volatile compounds, 36 key odour-active compounds were selected for analysis. Several extraction times, desorption times, temperature conditions and fibre types were tested to achieve a fast and reproducible extraction, and a representative analysis of the aroma profile of cooked beef. Extraction conditions and fibre type significantly affected the majority of the target compounds. Divinylbenzene-carboxen-polydimethylsiloxane (DVB-CAR-PDMS) fibre presented a better reproducibility at all extraction times and extracted more efficiently the less volatile compounds than the carboxen-polydimethylsiloxane (CAR-PDMS) fibre. The high molecular weight compounds seemed to achieve faster the equilibrium between the headspace and DVB-CAR-PDMS fibre. The use of SPME was shown to be a simple, sensitive, selective, representative, fast, and low-cost method for the evaluation of key odour-active compounds in cooked beef meat, even if further research on quantitative analysis of volatiles using SPME on solid samples has to be done. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

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See detailEvaluation of two protein extraction protocols for Pichia anomala proteome analysis.
Bajji, Mohammed; Delaplace, Pierre ULg; Mauro, Sergio et al

Poster (2009, May 19)

Pichia anomala (strain Kh6) was isolated from the surface of apple fruits and selected for its high and reliable biocontrol activity against Botrytis cinerea and Penicillium expansum. Its main modes of ... [more ▼]

Pichia anomala (strain Kh6) was isolated from the surface of apple fruits and selected for its high and reliable biocontrol activity against Botrytis cinerea and Penicillium expansum. Its main modes of action have until now been studied using essentially microbiological and molecular approaches. The study continues now using the proteomic approach and considering the in situ P. anomala/B. cinerea/apple interaction. Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) is one of the most powerful tools used for proteomic analysis. It combines two sequential separation steps, the first dimension via isoelectric focusing (IEF) and the second one by SDS PAGE. Although recent advances in 2-D PAGE, the extraction of the whole proteome and the removal of interfering contaminants still limit its application. Sample preparation constitutes indeed a critical influential step for IEF which in turn affects 2-D gel quality. The objective of the present work was thus to develop an effective protein extraction protocol designed for 2-D PAGE analysis of the proteome of P. anomala strain Kh6. As a starting point, two contrasting protein extraction protocols were chosen to be evaluated in terms of protein yield and one-dimensional (1-D) SDS PAGE and 2-D PAGE gel patterns. The first protocol uses a urea/thiourea-based lysis buffer whereas the second protocol utilizes a hot SDS-based lysis buffer with an additional precipitation step. The comparison model used consisted of apples treated with strain Kh6 alone (K) and apples first treated with Kh6 and then inoculated with B. cinerea conidia (KB). Growth kinetics of strain Kh6 on wounded apples was determined and found to be not affected by the presence of B. cinerea conidia. Proteins were extracted from yeast pellets collected at both the exponential and stationary phases of strain Kh6 growth on apples. The evaluation of both extraction protocols indicates that more proteins were extracted with the SDS protocol and, according to 1-D assays, higher molecular weight proteins were obtained with the ‘urea/thiourea’ protocol and, regardless of the protocol used, more bands were obtained during the exponential phase. 2-D assays are currently underway and the corresponding results will be presented. [less ▲]

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See detailevaluation of two protein extractions protocols for pichia anomala proteome analysis
Bajji, M.; Delaplace, Pierre ULg; Mauro, S. et al

Poster (2009)

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See detailThe evaluation of unmanned aerial systems-based photogrammetry and terrestrial laser scanning to generate DEMs of agricultural watersheds
Ouedraogo, Mohamar ULg; Degré, Aurore ULg; Debouche, Charles ULg et al

in Geomorphology (2014)

Agricultural watersheds tend to be places of intensive farming activities that permanently modify their microtopography. The surface characteristics of the soil vary depending on the crops that are ... [more ▼]

Agricultural watersheds tend to be places of intensive farming activities that permanently modify their microtopography. The surface characteristics of the soil vary depending on the crops that are cultivated in these areas. Agricultural soil microtopography plays an important role in the quantification of runoff and sediment transport because the presence of crops, crop residues, furrows and ridges may impact the direction of water flow. To better assess such phenomena, 3-D reconstructions of high-resolution agricultural watershed topography is essential. Fine-resolution topographic data collection technologies can be used to discern highly detailed elevation variability in these areas. Knowledge of the strengths and weaknesses of existing technologies used for data collection on agricultural watersheds may be helpful in choosing an appropriate technology. This study assesses the suitability of terrestrial laser scanning (TLS) and unmanned aerial system (UAS) photogrammetry for collecting the fine-resolution topographic data required to generate accurate, high-resolution digital elevation models (DEMs) in a small watershed area (12 ha). Because of farming activity, 14 TLS scans (≈ 25 points m− 2) were collected without using high-definition surveying (HDS) targets, which are generally used to mesh adjacent scans. To evaluate the accuracy of the DEMs created from the TLS scan data, 1,098 ground control points (GCPs) were surveyed using a real time kinematic global positioning system (RTK-GPS). Linear regressions were then applied to each DEM to remove vertical errors from the TLS point elevations, errors caused by the non-perpendicularity of the scanner’s vertical axis to the local horizontal plane, and errors correlated with the distance to the scanner’s position. The scans were then meshed to generate a DEMTLS with a 1 × 1 m spatial resolution. The Agisoft PhotoScan and MicMac software packages were used to process the aerial photographs and generate a DEMPSC (Agisoft PhotoScan) and DEMMCM (MicMac), respectively, with spatial resolutions of 1 × 1 m. Comparing the DEMs with the 1,098 GCPs showed that the DEMTLS was the most accurate data product, with a root mean square error (RMSE) of 4.5 cm, followed by the DEMMCM and the DEMPSC, which had RMSE values of 9.0 and 13.9 cm, respectively. The DEMPSC had absolute errors along the border of the study area that ranged from 15.0 to 52.0 cm, indicating the presence of systematic errors. Although the derived DEMMCM was accurate, an error analysis along a transect showed that the errors in the DEMMCM data tended to increase in areas of lower elevation. Compared with TLS, UAS is a promising tool for data collection because of its flexibility and low operational cost. However, improvements are needed in the photogrammetric processing of the aerial photographs to remove non-linear distortions. [less ▲]

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See detailEvaluation of us-guided percutaneous fine needle aspiration biopsyin thyroïd nodules
Meunier, Paul ULg; Collignon, J.; Thiry, Albert ULg et al

in International Congress of Head and neck Radiology - Abstract book (1997)

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See detailEvaluation of viability and growth of Acetobacter senegalensis under different stress conditions
Shafiei, Rasoul ULg; Thonart, Philippe ULg; Delvigne, Frank ULg et al

in International Journal of Food Microbiology (2013)

Acetic acid bacteria (AAB) are used in production of vinegars. During acetic acid fermentation, AAB encounter various aggressive conditions which may lead to a variety of cellular disorders. Previous ... [more ▼]

Acetic acid bacteria (AAB) are used in production of vinegars. During acetic acid fermentation, AAB encounter various aggressive conditions which may lead to a variety of cellular disorders. Previous researches mainly studied the influences of different carbon sources on tolerance of AAB to ethanol and acetic acid. In this study, different techniques were used comparatively to investigate the effects of preadaptation on the ability of A. senegalensis to tolerate ethanol and acetic acid. In general, the carbon sources used for preadaptation of A. senegalensis exhibited significant effects on the tolerance of cells to stressors. Flow-cytometric assessments of preadapted cells in ethanol showed that 87.3% of the cells perform respiration after exposure to a stress medium containing 5% (v/v) ethanol and 3% (w/v) acetic acid. However, 58.4% of these preadapted cells could keep their envelope integrity under the stress condition. They could also grow rapidly (μmax = 0.39/h) in the stress medium (E5A3) with a high yield (>80%). A. senegalensis grown in glucose exhibited a low tolerance to acetic acid. Analysis of their respiration capacity, membrane integrity and culturability revealed that almost all the population were dead after exposure to 5% (v/v) ethanol and 3% (w/v) acetic acid. In contrast, exposure of A. senegalensis preadapted in a mixture of glucose and acetic acid to a stress medium containing 5% (v/v) ethanol and 3% (w/v) acetic acid, exhibited an intact respiration system and cellular membrane integrity in 80.3% and 50.01% of cells, respectively. Moreover, just 24% of these cells could keep their culturability under that stress condition. [less ▲]

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See detailThe evaluation of vocal pitch accuracy: The case of operatic singing voices
Larrouy, Pauline ULg; Magis, David ULg; Morsomme, Dominique ULg

in Music Perception (2014), 32(1), 1-10

The objective analysis of Western operatic singing voices indicates that professional singers can be particularly “out of tune”. This study aims to better understand the evaluation of operatic voices ... [more ▼]

The objective analysis of Western operatic singing voices indicates that professional singers can be particularly “out of tune”. This study aims to better understand the evaluation of operatic voices, which have particularly complex acoustical signals. Twenty-two music experts were asked to evaluate the vocal pitch accuracy of 14 sung performances with a pairwise comparison paradigm, in a test and a retest. In addition to the objective measurement of pitch accuracy (pitch interval deviation), several performance parameters (average tempo, fundamental frequency of the starting note) and quality parameters (energy distribution, vibrato rate and extent) were observed and compared to the judges’ perceptual rating. The results show high intra- and inter-judge reliability when rating the pitch accuracy of operatic singing voices. Surprisingly, all the parameters were significantly related to the ratings and explain 78.8% of the variability of the judges’ rating. The pitch accuracy evaluation of operatic voices is thus not based exclusively on the precision of performed music intervals but on a complex combination of performance and quality parameters. [less ▲]

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See detailEvaluation of Water Resources Quality in Sabodala Gold Mining Region and Its Surrounding Area (Senegal)
Mall, Ibrahima; Diaw, Moctar; Dieng, Ndeye Maguette ULg et al

in Journal of Water Resource and Protection (2015), 7(3), 247-263

Geochemical and Geostatistical tools were used to assess: 1) the chemical quality and, geochemical processes in crystalline rock aquifers in Sabodala (Eastern Senegal) and its surroundings and 2) the ... [more ▼]

Geochemical and Geostatistical tools were used to assess: 1) the chemical quality and, geochemical processes in crystalline rock aquifers in Sabodala (Eastern Senegal) and its surroundings and 2) the impact of mining activities on their quality. A total of 26 water samples collected at boreholes, dug wells and stream, were analyzed to determine major and trace elements concentration focused on elements that represent more threats on human health. Boxplots define chemical characteristics of water for each aquifer formation compared to surface waters. Geostatistical analysis show two sources of water mineralization with regard to major elements: a first natural source characterized by Ca-Mg-HCO3 water type from boreholes and unpolluted surface water and a second group characterized by polluted water by nitrates with Na-NO3-Cl type mainly observed in upper weathered aquifers. However, considering trace element, geostatistical analysis showed three water groups: water with very low trace element concentrations encountered in boreholes and unpolluted surface waters, and waters with relatively high trace element concentrations such as Al observed in areas affected by gold mining activities and finally, polluted waters by Ni, Co, Mn and Cr observed at Sabodala. Results show that in eastern Senegal well waters are vulnerable and often affected by pollution. [less ▲]

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See detailEVALUATION OF α-SYNUCLEIN AS BIOMARKER OF PARKINSON'S DISEASE
Napp, Aurore ULg; Garraux, Gaëtan ULg; Servais, Anne-Catherine ULg et al

Conference (2013, October 17)

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See detailEvaluation over Greenland of WRF with GC-NET observations (1995-2005) by comparison with 2 other RCMs
Sacré, Bernard ULg; Fettweis, Xavier ULg; Doutreloup, Sébastien ULg et al

Conference (2011)

In the context of climate change, the Greenland Ice Sheet (GrIS) plays an important role in sea level variation and oceanic thermohaline circulation changes. Unfortunately, Global Climate Models do not ... [more ▼]

In the context of climate change, the Greenland Ice Sheet (GrIS) plays an important role in sea level variation and oceanic thermohaline circulation changes. Unfortunately, Global Climate Models do not illustrate enough the characteristics of Greenland. To solve that, specific RCMs have been developed to take into account the features of polar regions. In this project, we compare three RCMs : the MAR model, the RACMO model and the Weather Research and Forecasting (WRF) model. WRF is an open source model developed by the Mesoscale and Microscale Meteorology Division of NCAR. We use here the standard WRF (version 3.2.1) and its polar optimization (called polar WRF). The MAR version tuned for the GrIS and coupled with a 1D surface scheme called SISVAT (for Soil Ice Snow Vegetation Atmosphere Transfer) is compared here. The version of RACMO is a specific version for the Greenland climate, RACMO2/GR. This model contains a special surface module for snow-ice treatment and other modifications concerning, for example, the surface turbulence heat flux or the surface roughness. The comparison is made on a domain centered on Greenland at a 25-km horizontal resolution over the 1995-2005 period when Automatic Weather Station (AWS) measurements are available from the Greenland Climate NETwork (GC-NET). Statistics (mean, bias, RMSE, correlation coefficient) are calculated for the near-surface temperature, surface pressure, 10m-wind speed and specific humidity for winter (October to April) and summer (May to September). In addition, the modeled snowfall are evaluated with ice core-based snow accumulation climatologies. Comparison shows a significant improvement from RCMs compared to the reanalyses (NCEP2 and ERA-INTERIM) in respect to the AWS measurements. RACMO and MAR seem to compare better with observations than WRF. [less ▲]

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See detailEvaluation par les chômeurs de leur formation professionnelle
Jacquemain, Marc ULg; Dekerschieter, Maryse

Report (1999)

Le rapport comprend deux versants : un versant qualitatif par entretiens et un versant quantitatif par questionnaire. Il s'agissait de faire évaluer par les chômeurs en formation professionnelle, les ... [more ▼]

Le rapport comprend deux versants : un versant qualitatif par entretiens et un versant quantitatif par questionnaire. Il s'agissait de faire évaluer par les chômeurs en formation professionnelle, les raisons de leur participation (ou de leur abandon), les difficultés éprouvées, les bénéfices perçus. [less ▲]

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See detailEvaluation par questionnaire des inconvénients liés aux prothèses péniennes chez 25 implantés
Kempeneers, Philippe ULg; Andrianne, Robert ULg; Mormont, Christian ULg

in Andrologie : Journal Officiel de la Société d'Andrologie de Langue Française (1992), 2

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See detailEvaluation par ultrasonographie en temps réel de la teneur en gras intramusculaire du porc Piétrain
Youssao, A. K. I.; Verleyen, Vincent ULg; Michaux, Charles ULg et al

in Annales de Médecine Vétérinaire (2002), 146(4), 249-255

Real-time ultrasound data collection, consisting specifically of longissimus thoracis muscle echogenicity, was carried out on 80 Pietrain pigs (42 gilts and 34 barrows) using the Pie Medical scanner 200 ... [more ▼]

Real-time ultrasound data collection, consisting specifically of longissimus thoracis muscle echogenicity, was carried out on 80 Pietrain pigs (42 gilts and 34 barrows) using the Pie Medical scanner 200 equipped with an ASP-18 probe and 3.5 MHz to predict intramuscular fat. Two ribs thickness (12th and 13th ribs) was excised from the longissimus thoracis muscle for subsequent ether extract value (EE) determination. The percentage of white pixels in the ultrasound image were related to EE percentage. The EE percentages were 1.44, 1.37 and 1.15 % respectively for the homozygous stress-negative Pietrain (CC), heterozygous stress-negative Pietrain (CT) and homozygous stress-positive Pietrain (TT) individuals. The percentage of white pixels in the longissimus thoracis images were 9.98, 8.75 and 7.79 % respectively for CC, CT and TT genotypes. The barrows had an higher intramuscular fat and white pixel percentage than the gilts. The determination coefficient (R 2) of the EE prediction model originating from the white pixels percentage was 0.35 with a root mean squared error of 0.26 %. These performance could be potentially improved using the calibration phantom of the ASP-18 probe, before taking images. [less ▲]

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See detailEvaluation patrimoniale des droits à la pension en Belgique
Bouillot, L.; Perelman, Sergio ULg

in Revue Belge de Sécurité Sociale (1995)

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See detailEvaluation patrimoniale des droits à la pension en Belgique
Perelman, Sergio ULg

in Cahiers Economiques de Bruxelles (1981), (89), 25-52

Detailed reference viewed: 10 (3 ULg)