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See detailDetermination of isotopic fractionation delta13C of methane from ground-based FTIR observations performed at the Jungfraujoch
Duchatelet, Pierre ULiege; Mahieu, Emmanuel ULiege; Sussmann, Ralf et al

Poster (2009, April)

Atmospheric methane (CH4) is a strong greenhouse gas that has important chemical impacts on both the troposphere and the stratosphere. In the troposphere, oxidation of methane is a major regulator of OH ... [more ▼]

Atmospheric methane (CH4) is a strong greenhouse gas that has important chemical impacts on both the troposphere and the stratosphere. In the troposphere, oxidation of methane is a major regulator of OH and is a source of formaldehyde, carbon monoxide and hydrogen. In the stratosphere, CH4 plays a central role (i), due to its contribution to the stratospheric water vapor budget, and (ii), as a sink for chlorine atoms which reduces the rate of stratospheric ozone depletion. Because the different sources of methane (natural and anthropogenic like wetlands, rice paddies, termites, natural gas escape, biomass burning, etc) have distinct 13C/12C ratios (usually reported in “delta” notation δ13C), measurements of atmospheric 13CH4 content, in addition to those of the main isotopologue (12CH4), can be used to investigate individual source strengths as well as their spatial and temporal distributions. Characterization of the isotopic fractionation of methane is therefore important, for example, to help models constrain estimates of the global methane budget. However, experimental data for the 13C/12C isotope ratio are sparse. The currently accepted average value of δ13C in atmospheric methane is about -47‰ (Platt et al., 2004). The first goal of this work is to develop and to characterize (in terms of information content and error budget) an original retrieval approach to derive 13CH4 columns from ground-based Fourier transform infrared (FTIR) spectra recorded at the International Scientific Station of the Jungfraujoch (ISSJ; 46.5°N, 8.0°E, 3580m a.s.l., Swiss Alps). The retrieval strategy is based on a Tikhonov L1 approach which has been originally developed for 12CH4 by Sussmann et al. (2008) [see also contributions by Sussmann et al. to this conference (EGU2009-7869)]. In order to validate our 13CH4 products, comparisons with satellite ACE-FTS (Atmospheric Chemistry Experiment - Fourier Transform Spectrometer) measurements are performed. Then, atmospheric δ13C ratios derived from the FTIR measurements will be compared to values published in the literature and critically discussed. References: Platt, U., W. Allan and D. Lowe, Hemispheric average Cl atom concentration from 13C/12C ratios in atmospheric methane, Atmos. Chem. Phys., 4, 2393-2399, 2004. Sussmann, R., Forster, F., Borsdorff, T., et al.: Satellite validation of column-averaged methane on global scale: ground-based data from 15 FTIR stations versus last generation ENVISAT/SCIAMACHY retrievals, IGAC 10th International Conference, Annecy, France, 7-12 Sep 2008. [less ▲]

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See detailDetermination of ITM Key Parameters By the Ionospheric Connection Explorer (ICON)
Immel, T. J.; England, S.; Mende, S. B. et al

Conference (2014)

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See detailDetermination of kinetics and the crystal structure of a novel type 2 isopentenyl diphosphate: dimethylallyl diphosphate isomerase from Streptococcus pneumoniae.
de Ruyck, Jerome; Janczak, Matthew W.; Neti, Syam Sundar et al

in Chembiochem : a European journal of chemical biology (2014), 15(10), 1452-1458

Isopentenyl diphosphate isomerase (IDI) is a key enzyme in the isoprenoid biosynthetic pathway and is required for all organisms that synthesize isoprenoid metabolites from mevalonate. Type 1 IDI (IDI-1 ... [more ▼]

Isopentenyl diphosphate isomerase (IDI) is a key enzyme in the isoprenoid biosynthetic pathway and is required for all organisms that synthesize isoprenoid metabolites from mevalonate. Type 1 IDI (IDI-1) is a metalloprotein that is found in eukaryotes, whereas the type 2 isoform (IDI-2) is a flavoenzyme found in bacteria that is completely absent from human. IDI-2 from the pathogenic bacterium Streptococcus pneumoniae was recombinantly expressed in Escherichia coli. Steady-state kinetic studies of the enzyme indicated that FMNH2 (KM =0.3 muM) bound before isopentenyl diphosphate (KM =40 muM) in an ordered binding mechanism. An X-ray crystal structure at 1.4 A resolution was obtained for the holoenzyme in the closed conformation with a reduced flavin cofactor and two sulfate ions in the active site. These results helped to further approach the enzymatic mechanism of IDI-2 and, thus, open new possibilities for the rational design of antibacterial compounds against sequence-similar and structure-related pathogens such as Enterococcus faecalis or Staphylococcus aureus. [less ▲]

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See detailDetermination of lidocaine and its two N-desethylated metabolites in dog and horse plasma by high-performance liquid chromatography combined with electrospray ionization tandem mass spectrometry
Maes, A.; Weiland, L.; Sandersen, Charlotte ULiege et al

in Journal of Chromatography. B : Analytical Technologies in the Biomedical & Life Sciences (2007), 852(1-2), 180-187

A sensitive method for the quantification of lidocaine and its metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), in animal plasma using high-performance liquid chromatography combined ... [more ▼]

A sensitive method for the quantification of lidocaine and its metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), in animal plasma using high-performance liquid chromatography combined with electrospray ionization mass spectrometry is described. The sample preparation includes a liquid-liquid extraction with methyl tert-butylmethyl ether after addition of 2 M sodium hydroxide. Ethyl methylglycinexylidide (EMGX) is used as an internal standard. For chromatographic separation, an ODS Hypersil column was used. Isocratic elution was achieved with 0.0 1 M ammonium acetate and acetonitrile as mobile phases. Good linearity was observed in the range of 2.5-1000 ng ml(-1) for lidocame in both dog and horse plasma. For MEGX, linear calibration curves were obtained in the range of 5-1000 ng ml(-1) and 20-1000 ng ml(-1) for dog and horse plasma, respectively. In dog and horse plasma good linearity was observed in the range of 200-1500 ng ml(-1) for GX. The limit of quantification (LOQ) in dog plasma for lidocaine, MEGX and GX was set at 2.5 ng ml(-1), 20 ng ml(-1) and 200 ng ml(-1), respectively. For horse plasma a limit of quantification of 2.5 ng ml(-1), 5 ng ml(-1) and 200 ng ml(-1) was achieved for lidocaine, MEGX and GX, respectively. In dog plasma, the limit of detection (LOD) was found to be 0.8 ng ml(-1), 2.3 ng ml(-1) and 55 ng ml(-1) for lidocaine, MEGX and GX, respectively. In horse plasma the LOD's found for lidocame, MEGX and GX, were 1.1 ng ml(-1), 0.5 ng ml(-1) and 13 ng ml(-1), respectively. The method was shown to be of use in pharmacokinetic studies after application of a transdermal patch in dogs and after an intravenous infusion in horses. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailDetermination of liquid hold-up and flow distribution inside modular catalytic structured packings
Viva, Aurora; Aferka, Saïd ULiege; Toye, Dominique ULiege et al

in Chemical Engineering Research & Design : Transactions of the Institution of Chemical Engineers Part A (2011), 89

This paper presents the results of a study carried out to examine liquid hold-up and flow distribution in a 0.1m internal diameter column filled with catalytic structured packing Katapak-SP. Information ... [more ▼]

This paper presents the results of a study carried out to examine liquid hold-up and flow distribution in a 0.1m internal diameter column filled with catalytic structured packing Katapak-SP. Information has been gathered at local scale by means of a non-intrusive high energy X-ray tomograph. Measurements have been carried out in a large number of packing cross sections situated at different heights between the top and bottom of the packed column, giving access to the evolution of axial profiles of liquid hold-up in the open channels (separation zone) and in the catalytic baskets (reaction zone) as a function of the liquid load. The total hold-up, evaluated by averaging local tomographic values over the packed volume, was compared with global hold-up data obtained by traditional methods, like draining and RTD measurements. A method was also proposed to deduce the distribution of liquid flowrate, between the reaction and the separation zones, from hold-up distribution measured by tomography. The methodology was validated by comparison with experimental data obtained by collecting separately the liquid flowing out of the two zones at the bottom of the packed bed. The obtained results are invaluable to improve the description of hydrodynamics in rate based performance models. [less ▲]

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See detailDetermination of loading scenarios on buildings due to column damage
Colomer, Carles Segura; Hamra, Lotfi; D'Antimo, Marina ULiege et al

in Structures (2017), Volume 12

The majority of imaginable (and relevant) accidental scenarios on building structures are initiated at the ground level by a column suffering damage, mainly due to a localized explosion or a vehicle ... [more ▼]

The majority of imaginable (and relevant) accidental scenarios on building structures are initiated at the ground level by a column suffering damage, mainly due to a localized explosion or a vehicle impact. The transmitted vertical forces from the column to the structure are decisive in understanding the response of the building and are the subject of analysis of this paper. The classic definition of a column loss scenario is extended here by means of a simplified analytical approach to characterize the axial forces appearing in the column during the damage process. A simple closed-form solution is proposed to define the loading scenario on the structure and compared to the classic rectangular (un)loading approach. In certain cases, the proposed analysis shows a more unfavorable loading situation for the structure, which needs to be accounted for during design. [less ▲]

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See detailDetermination of mass-loss rates from early-type stars on the basis of 'log(W1)-log(W1 0)' diagrams
Surdej, Jean ULiege

in Astronomy and Astrophysics (1983), 127

Using realistic expressions for the velocity and opacity distributions in rapidly expanding atmospheres, the author presents numerical results for the first order moment W[SUB]1[/SUB] of a P Cygni line ... [more ▼]

Using realistic expressions for the velocity and opacity distributions in rapidly expanding atmospheres, the author presents numerical results for the first order moment W[SUB]1[/SUB] of a P Cygni line profile calculated as a function of the parameter W[SUB]1[/SUB][SUP]0[/SUP] â Mn(level), where Mrepresents the mass-loss rate and n(level) the average fractional abundance of the relevant ion. The calculations clearly show that the resulting "log(W[SUB]1[/SUB]) - log(W[SUB]1[/SUB][SUP]0[/SUP])" curves depend almost essentially on the opacity distribution and that for unsaturated P Cygni line profiles the relation W[SUB]1[/SUB] â Mn(level) holds irrespective of the both distributions. For W[SUB]1[/SUB] ⪠0.24, the line profiles become saturated and the first order moment W[SUB]1[/SUB] does not provide anymore accurate information on the mass-loss rate. This technique of mass-loss determination and that which consists in fitting observed line profiles with theoretical ones are compared. [less ▲]

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See detailDetermination of mass-loss rates from the first order moment W1 of unsaturated Cygni line profiles
Surdej, Jean ULiege

in Astrophysics & Space Science (1982), 88

The relationship between the first order moment and the mass loss rate is investigated within the framework of the Sobolev approximation (1947, 1957, 1958) under various physical and geometrical ... [more ▼]

The relationship between the first order moment and the mass loss rate is investigated within the framework of the Sobolev approximation (1947, 1957, 1958) under various physical and geometrical conditions. By assuming that the size of the expanding envelope from which the observed P Cygni profiles arise is large with respect to the central stellar core, a general expression for the n-th order moment is obtained for the case of a point-like source in terms of the usual parameters inherent to Sobolev-type theories. It is then shown how the first result is altered when considering separately the effects due to collisions and rotation, the presence of the underlying photospheric absorption line, the finite size of the central core, and the limb-darkening of the stellar core. It is concluded that the total uncertainty of the mass loss rate determination made with the approach proposed here should be less than 60 percent. [less ▲]

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See detailDetermination of mass-loss rates of planetary nebulae nuclei using the first order moment of P Cygni line profiles.
Hutsemekers, Damien ULiege; Surdej, Jean ULiege

in Comptes rendus sur les Journées de Strasbourg, 8ème réunion - Les Nébuleuses Planétaires (1986)

The authors conclude that the mass-loss rates of planetary nebulae nuclei derived by Cerruti-Sola, Perinotto (1985) have been systematically underestimated by one or nearly two orders of magnitude.

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See detailThe Determination of Megakaryocyte Ploidy
Paulus, Jean-Michel ULiege; Senterre, J. M.; von Frenckell, R.

in International Journal of Cell Cloning (1990), 8(4), 227-35

Methods which have been used to determine megakaryocyte ploidy in animals and humans are reviewed. Although the number of megakaryocyte nuclear units counted in bone marrow squashes is roughly ... [more ▼]

Methods which have been used to determine megakaryocyte ploidy in animals and humans are reviewed. Although the number of megakaryocyte nuclear units counted in bone marrow squashes is roughly proportional to ploidy, accurate determinations of DNA content require the use of microphotometry or flow cytometry. New techniques should make it possible to distinguish polyploidizing megakaryoblasts from promegakaryocytes and mature megakaryocytes which have arrested polyploidization. Only the latter should be included in histograms of the number of endoduplications, since only those have expressed their full polyploidization potential. Statistical techniques are available for analysis and comparison of both raw ploidy distributions or histograms of endoduplication numbers. [less ▲]

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See detailDetermination of Meprobamate in Pharmaceutical Dosage Forms Also Containing Carbromal by Liquid Chromatography and Indirect Photometric Detection
Bechet, I.; Ceccato, Attilio ULiege; Hubert, Philippe ULiege et al

in Journal of Pharmaceutical & Biomedical Analysis (1992), 10(10-12, Oct-Dec), 995-9

In a pharmaceutical form also containing carbromal, meprobamate could not be quantified selectively by classical methods described in pharmacopoeias due to a significant interference from carbromal ... [more ▼]

In a pharmaceutical form also containing carbromal, meprobamate could not be quantified selectively by classical methods described in pharmacopoeias due to a significant interference from carbromal. Consequently, reversed-phase HPLC methods have been developed to separate the two active ingredients using indirect photometric detection to visualize and determine meprobamate which has very poor chromophoric properties. Different parameters influencing the sensitivity of the indirect response, such as the nature of the highly absorbing compound added to the mobile phase (the marker) as well as the methanol content and the pH of this phase, have been studied. Two chromatographic systems containing benzoic acid or cinnamic acid as the marker, have been optimized and validated. Good linearity and reproducibility have been obtained with both systems but the cinnamic acid method has the advantage that meprobamate and carbromal can be determined simultaneously at 273 nm. [less ▲]

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See detailDetermination of methionine requirement of growing double-muscled Belgian Blue bull.
Froidmont, Eric; Beckers, Yves ULiege; Thewis, André ULiege

in Book of abstract of the VIIIth International Symposium on Protein Metabolism and Nutrition. (1999)

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See detailDetermination of minimal serum estradiol for prevention of postmenopausal bone loss
Sarlet, N; Reginster, Jean-Yves ULiege; GASPARD, Ulysse ULiege et al

in Calcified Tissue International (1989), 44

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See detailDetermination of minimum effective doses of luteinizing hormone and human chorionic gonadotropin for intrafollicular treatment to induce ovulation in dairy heifers.
Mala, J; Beckers, Jean-François ULiege; Melo de Sousa, Noelita ULiege et al

in Acta Veterinaria BRNO (2013), 82

The aim of this study was to determine the minimum effective intrafollicular doses of luteinizing hormone and human chorionic gonadotropin in order to induce ovulation in cycling dairy heifers that have ... [more ▼]

The aim of this study was to determine the minimum effective intrafollicular doses of luteinizing hormone and human chorionic gonadotropin in order to induce ovulation in cycling dairy heifers that have not yet been adequately established. Application of 10, 5, 1, 0.5, 0.1, 0.01 and 0.001 µg luteinizing hormone as well as 10, 1, 0.1, 0.01 and 0.001 international units (IU) of human chorionic gonadotropin in dominant follicles was performed on day 7 of the oestrous cycle. Control animals were given luteinizing hormone (12.5 mg and 25 mg) or human chorionic gonadotropin (2000 IU) intravenously. Accessory corpus luteum on day 14 of the oestrous cycle was considered as an evidence of ovulation. Ovulation was observed in 2 out of 3 heifers in each treatment group (n = 3) after administration of 10–0.1 µg luteinizing hormone (except for 0.5 µg – ovulation in 3 of 3 heifers), in all heifers after administration of 10–0.01 IU human chorionic gonadotropin as well as in all control heifers. Administration of 0.01 µg and 0.001 µg luteinizing hormone as well as of 0.001 IU human chorionic gonadotropin did not result in ovulation. Higher progesterone concentration on day 14 vs. day 7 of the oestrous cycle was found after all treatments. Nevertheless, the differences were signicant (P < 0.05) only after intrafollicular treatments with 5, 1 and 0.001 µg luteinizing hormone as well as 10, 1 and 0.01 IU human chorionic gonadotropin. In conclusion, minimum efcient doses for intrafollicular treatment of the dominant follicles in cycling heifers capable of inducing ovulation were 0.1 µg of luteinizing hormone and 0.01 IU of human chorionic gonadotropin. This is the rst study describing the intrafollicular luteinizing hormone administration in cycling dairy heifers. [less ▲]

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See detailDetermination of Moisture Diffusivity During Drying of Mortar Cement: Experimental and Modeling Study
Bennamoun, Lyes ULiege; Kahlerras, Loubna ULiege; Michel, Frédéric ULiege et al

in International Journal of Energy Engineering (2013), 3(1), 1-6

The aim of this study is the experimental characterization of the behaviour of a mortar during convective drying. We focalise on mortar that has a rate water-cement of 0.5. The drying tests are developed ... [more ▼]

The aim of this study is the experimental characterization of the behaviour of a mortar during convective drying. We focalise on mortar that has a rate water-cement of 0.5. The drying tests are developed in a micro-convective dryer that can use samples weighing from 0 to 8g. The advantage of these experiments is to reproduce the natural conditions that can be found during the treatment of the mortar-atmosphere problems. The response of the drying curve or the drying kinetic depends on the applied drying conditions. So, the temperature of the air varies from 60°C to 130°C, the velocity of the air is changed from 2 m.s-1 to 5 m. s-1and the relative humidity is kept less than 1.7%. The comparison between the experimental results and the proposed analytical solutions of the equation of diffusion represented by Fick’s law, applied for a finite shape, allows determination of the values of the diffusion coefficient. It has a value of 1.71×10-10 m2.s-1 at 60°C, 13.69×10-10 m2.s-1 at 90°C and 16.27×10-10 m2.s-1 at 130°C. Calculation of the activation energy and the D0 constant are also possible. [less ▲]

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See detailDetermination of muscle mitochondrial respiratory capacity in Standardbred racehorses as an aid to predicting exertional rhabdomyolysis
Houben, Rosa ULiege; Leleu, Claire; Fraipont, Audrey ULiege et al

in Mitochondrion (2016), 24

This prospective cohort study evaluated the potential of high-resolution respirometry applied to permeabilized muscle fibers for fitness evaluation in French Standardbred racehorses. Fitness evaluation by ... [more ▼]

This prospective cohort study evaluated the potential of high-resolution respirometry applied to permeabilized muscle fibers for fitness evaluation in French Standardbred racehorses. Fitness evaluation by means of respirometric parameters did not correlate with racing performance registered over the following racing season. However, altered mitochondrial energy metabolism was associated with higher risk of developing exertional rhabdomyolysis, a common cause of exercise intolerance in racehorses. These data represent a first step towards establishing reference values for muscle OXPHOS capacity in this breed. [less ▲]

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See detailDetermination of myoglobin in serum by kinetic turbidimetry, using the turbitimesystem
Chapelle, Jean-Paul ULiege; El Allaf, M.

in Clinical Chemistry (1990), 36(6), 1193

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See detailDetermination of N-acetylcysteine and its metabolites in plasma by LC-MS-MS
Toussaint, B.; Streel, B.; Ceccato, Attilio ULiege et al

Poster (2000)

Detailed reference viewed: 141 (4 ULiège)