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
Peer Reviewed
See detailAutomated Determination of Verapamil and Norverapamil in Human Plasma with on-Line Coupling of Dialysis to High-Performance Liquid Chromatography and Fluorometric Detection
Ceccato, Attilio ULg; Chiap, Patrice ULg; Hubert, Philippe ULg et al

in Journal of Chromatography. A (1996), 750(1-2), 351-60

A fully automated method for the simultaneous determination of verapamil and its main metabolite norverapamil in human plasma is described. This method is based on on-line sample preparation using ... [more ▼]

A fully automated method for the simultaneous determination of verapamil and its main metabolite norverapamil in human plasma is described. This method is based on on-line sample preparation using dialysis followed by clean-up and enrichment of the dialysate on a precolumn and subsequent HPLC analysis with fluorometric detection. All sample handling operations were performed automatically by a sample processor equipped with a robotic arm (ASTED system). The plasma samples were dialysed on a cellulose acetate membrane (cut-off: 15 kD) and the dialysate was purified and enriched on a short pre-column filled with cyanopropyl silica. Before starting dialysis, this trace enrichment column (TEC) was first conditioned with the HPLC mobile phase and then with pH 3.0 acetate buffer. 370 microliters of plasma sample spiked with the internal standard (gallopamil) were dialysed in the static-pulsed mode. The solution at the donor side was pH 3.0 acetate buffer containing Triton X-100 while the acceptor solution was made of the same acetate buffer. When dialysis was discontinued, the analytes were desorbed from the TEC by the HPLC mobile phase and transferred to the C18 analytical column by means of a switching valve. This mobile phase consisted of a mixture of acetonitrile, pH 3.0 acetate buffer and 2-aminoheptane. The influence of different parameters of the dialysis process on the recovery of verapamil and norverapamil has been studied. The effect of the volume, the aspirating and dispensing flow-rates of the dialysis solution has been investigated. The recoveries of verapamil and norverapamil in plasma were close to 75% and the limits of quantification were 5 ng/ml for both analytes. The method was found to be linear in the concentration range from 5 to 500 ng/ml (r2: 0.9996 for both analytes). The intra-day and inter-day reproducibilities at a concentration of 100 ng/ml were 2.3% and 5.6% for verapamil and 1.7% and 5.1% for norverapamil, respectively. [less ▲]

Detailed reference viewed: 12 (0 ULg)
Full Text
Peer Reviewed
See detailAutomated EEG entropy measurements in coma, vegetative state/unresponsive wakefulness syndrome and minimally conscious state
Gosseries, Olivia ULg; Schnakers, Caroline ULg; LEDOUX, Didier ULg et al

in Functional Neurology (2011)

Monitoring the level of consciousness in brain injured patients with disorders of consciousness is crucial as it provides diagnostic and prognostic information. Behavioral assessment remains the gold ... [more ▼]

Monitoring the level of consciousness in brain injured patients with disorders of consciousness is crucial as it provides diagnostic and prognostic information. Behavioral assessment remains the gold standard for assessing consciousness but previous studies have shown a high rate of misdiagnosis. This study aimed to investigate the usefulness of electroencephalography (EEG) entropy measurements in differentiating unconscious (coma or vegetative) from minimally conscious patients. Left fronto-temporal EEG recordings (10-minute resting state epochs) were prospectively obtained in 56 patients and 16 age-matched healthy volunteers. Patients were assessed in the acute (≤1 month post-injury;n=29) or chronic (>1 month post-injury; n=27) stage. The etiology was traumatic in 23 patients. Automated online EEG entropy calculations (providing an arbitrary value ranging from 0 to 91) were compared with behavioral assessments (Coma Recovery Scale-Revised) and outcome. EEG entropy correlated with Coma Recovery Scale total scores (r=0.49). Mean EEG entropy values were higher in minimally conscious (73±19; mean and standard deviation) than in vegetative/unresponsive wakefulness syndrome patients (45±28). Receiver operating characteristic analysis revealed an entropy cut-off value of 52 differentiating acute unconscious from minimally conscious patients (sensitivity 89% and specificity 90%). In chronic patients, entropy measurements offered no reliable diagnostic information. EEG entropy measurements did not allow prediction of outcome. User-independent time-frequency balanced spectral EEG entropy measurements seem to constitute an interesting diagnostic – albeit not prognostic – tool for assessing neural network complexity in disorders of consciousness in the acute setting. Future studies are needed before using this tool in routine clinical practice, and these should seek to improve automated EEG quantification paradigms in order to reduce the remaining false negative and false positive findings. [less ▲]

Detailed reference viewed: 269 (11 ULg)
See detailAutomated extraction and clean-up system for liquid materials
Focant, Jean-François ULg; De Pauw, Edwin ULg

Scientific conference (2004, April)

Detailed reference viewed: 2 (0 ULg)
See detailAutomated extraction and clean-up system for solid materials
Focant, Jean-François ULg; De Pauw, Edwin ULg

Scientific conference (2004, April)

Detailed reference viewed: 1 (0 ULg)
Peer Reviewed
See detailAutomated HPLC analysis of diltiazem and desacetyldiltiazem in plasma using disposabele extraction cartridges
Chiap, Patrice ULg; Hubert, Philippe ULg; Bechet, Isabelle et al

in Journal de Pharmacie de Belgique (1992), 47

Detailed reference viewed: 10 (3 ULg)
Full Text
Peer Reviewed
See detailAutomated Liquid Chromatographic Determination of Atenolol in Plasma Using Dialysis and Trace Enrichment on a Cation-Exchange Precolumn for Sample Handling
Chiap, Patrice ULg; Buraglia, B. M.; Ceccato, Attilio ULg et al

in Journal of Chromatography. B : Biomedical Sciences and Applications (2000), 739(1), 205-17

A fully automated method involving dialysis combined with trace enrichment was developed for the liquid chromatographic (LC) determination of atenolol, a hydrophilic beta-blocking agent, in human plasma ... [more ▼]

A fully automated method involving dialysis combined with trace enrichment was developed for the liquid chromatographic (LC) determination of atenolol, a hydrophilic beta-blocking agent, in human plasma. The plasma samples were dialysed on a cellulose acetate membrane and the dialysate was reconcentrated on a short trace enrichment column (TEC) packed with a strong cation-exchange material. All sample handling operations can be executed automatically by a sample processor (ASTED system). After TEC conditioning, the plasma sample, to which the internal standard (sotalol, another hydrophilic beta-blocker) was automatically added, was introduced in the donor channel and dialysed in the static/pulsed mode. The dialysis liquid consisted of 4.3 mM phosphoric acid. When the dialysis process was discontinued, the analytes were eluted from the TEC in the back-flush mode by the LC mobile phase and transferred to the analytical column, packed with octyl silica. The LC mobile phase consisted of phosphate buffer, pH 7.0-methanol (81:19; v/v) with 1-octanesulfonate. Atenolol and the internal standard were monitored photometrically at 225 nm. The different parameters influencing the dialysis and trace enrichment processes were optimised with respect to analyte recovery. The influence of two different kinds of cation-exchange material on analyte recovery and peak efficiency was also studied. The method was then validated in the concentration range 25-1000 ng/ml. The mean recovery for atenolol was 65% and the limit of quantitation was 25 ng/ml. [less ▲]

Detailed reference viewed: 18 (3 ULg)
Full Text
Peer Reviewed
See detailAutomated method for the determination of a new matrix metalloproteinase inhibitor in ovine plasma and serum by coupling of restricted access material for on-line sample clean-up to liquid chromatography
Chiap, Patrice ULg; Piette, Marie ULg; Evrard, Brigitte ULg et al

in Journal of Chromatography. B : Analytical Technologies in the Biomedical & Life Sciences (2005), 817(1), 109-117

A fully automated liquid chromatographic method was developed for the determination of Ro 28-2653, a new synthetic inhibitor of matrix metalloproteinases (MMPs), in ovine serum and plasma. The method was ... [more ▼]

A fully automated liquid chromatographic method was developed for the determination of Ro 28-2653, a new synthetic inhibitor of matrix metalloproteinases (MMPs), in ovine serum and plasma. The method was based on the coupling of a pre-column packed with restricted access material, namely LiChrospher RP-8 ADS (alkyl diol silica), for sample clean-up to an analytical column containing octyl silica stationary phase. One hundred mul of biological sample, to which 2-propanol was automatically added, were injected onto the ADS pre-column, which was then washed with a washing liquid consisting of a mixture of 25 mM phosphate buffer (pH 7.0) and acetonitrile (90: 10; v/v) for 10 min. By rotation of the switching valve, the analyte was then eluted in the back-flush mode with the LC mobile phase composed of a mixture of acetonitrile and 25 mM phosphate buffer (pH 7.0) (57:43; v/v). The UV detection was performed at 395 nm. The main parameters likely to influence the sample preparation technique were investigated. The method was then validated over a concentration range from 17.5 to 1950 ng/mI, the first concentration level corresponding to the lower limit of quantitation. At this concentration level, the mean bias and the R.S.D. value for intermediate precision were -2.4% and 4.2%, respectively. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 61 (18 ULg)
Full Text
Peer Reviewed
See detailAn automated method to extract fluvial terraces from digital elevation models: The Vesdre valley, a case study in eastern Belgium
Demoulin, Alain ULg; Bovy, Benoît ULg; Rixhon, Gilles ULg et al

in Geomorphology (2007), 91(1-2), 51-64

Fluvial terraces are a powerful tool for unraveling the combined tectonic and climatic conditions that controlled, directly or indirectly, the Quaternary incision of rivers. Terrace long profiles are ... [more ▼]

Fluvial terraces are a powerful tool for unraveling the combined tectonic and climatic conditions that controlled, directly or indirectly, the Quaternary incision of rivers. Terrace long profiles are usually retrieved from sparse traces of ancient floodplains preserved in the present topography. However, when these traces classically collected from topographic maps, aerial photographs, and field analyses are too few, the inferred profiles may be questionable. Yet the now available high quality and high resolution digital elevation models (DEMs) offer an opportunity to increase greatly the quantity of information usable to reconstruct terrace profiles. Therefore, the purpose of this study was to develop a new DEM-based method of terrace recognition in order to create a larger database and better constrain the profile reconstruction. Moreover, particular procedures of image and numerical processing were defined to fully automate the analysis. Basically, our method relies on the production of bivariate scatter plots depicting the relation between slope and relative altitude (i.e., the altitude above the current alluvial plain) for all pixels of successive sections of the valley. For each scatter plot, the curve of the lowest slope values observed at every relative altitude is smoothed and its minima are assumed to locate the altitudes of the "terrace" elements preserved in the section. We successfully tested this method in the Vesdre valley, incised in the NE Ardenne massif (E Belgium), notably identifying fault deformation of the profiles. The main advantages of our approach are its objectivity, exhaustiveness, and rapidity, allowing fast and coherent analysis of many rivers over extended regions. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 121 (33 ULg)
Full Text
See detailAutomated Mineral Mapping in Optical Ore Microscopy : accuracy and limitations
Pirard, Eric ULg

Conference (2012, September 03)

Detailed reference viewed: 130 (22 ULg)
Full Text
See detailAutomated Phase Map Referencing Against Historic Map Data
Groves, Roger; De Rauw, Dominique ULg; Thizy, Cédric ULg et al

in Osten, W.; Kujawinska, M. (Eds.) Fringe 2009 (2009, September)

Holography and shearography techniques are in common use for precise measurements in high technology industries, such as aerospace, automotive, precision manufacturing and for the structural diagnostics ... [more ▼]

Holography and shearography techniques are in common use for precise measurements in high technology industries, such as aerospace, automotive, precision manufacturing and for the structural diagnostics of artwork. The phase map data generated by these instruments allows precise measurements of parameters such as displacement, strain and shape. The comparison of data from different measurement campaigns is useful for null testing components and for studying changes. However, the comparison of data with previous measurements is non-trivial due to the sensitivity of these techniques to alignment and to sample loading parameters. This paper addresses image and phase registration issues for holography and shearography. This manuscript describes 2D spatial co-registration to compensate for differences between the field of view between the measurements and a phase referencing to calculate the difference between the phase maps. These techniques are implemented after following a standardised measurement procedure. [less ▲]

Detailed reference viewed: 19 (2 ULg)
Full Text
Peer Reviewed
See detailAutomated platform for the quality control of PET-CT scanners following AFCN/FANC recommendations
Bernard, Claire ULg; Paulus, Cyril; JODOGNE, Sébastien ULg et al

in Proceedings of the Belgian Hospital Physicists Association Symposium (2013, February)

Detailed reference viewed: 28 (15 ULg)
See detailAutomated procedures in ISO17025 routine dioxin laboratory: impact on throughput
Focant, Jean-François ULg

Scientific conference (2012, April)

Detailed reference viewed: 13 (1 ULg)