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See detailFast and slow spindle involvement in the consolidation of a new motor sequence
Barakat, M.; Doyon, J.; Debas, K. et al

in Behav Brain Res (2011), 217(1), 117-21

This study aimed to determine the distinct contribution of slow (11-13 Hz) and fast (13-15 Hz) spindles in the consolidation process of a motor sequence learning task (MSL). Young subjects (n = 12) were ... [more ▼]

This study aimed to determine the distinct contribution of slow (11-13 Hz) and fast (13-15 Hz) spindles in the consolidation process of a motor sequence learning task (MSL). Young subjects (n = 12) were trained on both a finger MSL task and a control (CTRL) condition, which were administered one week apart in a counterbalanced order. Subjects were asked to practice the MSL or CTRL task in the evening (approximately 9:00 p.m.) and their performance was retested on the same task 12h later (approximately 9:00 a.m.). Polysomnographic (PSG) recordings were performed during the night following training on either task, and an automatic algorithm was used to detect fast and slow spindles and to quantify their characteristics (i.e., density, amplitude, and duration). Statistical analyses revealed higher fast (but not slow) spindle density after training on the MSL than after practice of the CTRL task. The increase in fast spindle density on the MSL task correlated positively with overnight performance gains on the MSL task and with difference in performance gain between the MSL and CTRL tasks. Together, these results suggest that fast sleep spindles help activate the cerebral network involved in overnight MSL consolidation, while slow spindles do not appear to play a role in this mnemonic process. [less ▲]

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See detailFast and slow tracks in lysozyme folding: Insight into the role of domains in the folding process
Matagne, André ULg; Radford, S. E.; Dobson, C. M.

in Journal of Molecular Biology (1997), 267(5), 1068-1074

The folding of lysozyme involves parallel events in which hydrogen exchange kinetics indicate the development of persistent structure at very different rates. We have monitored directly the kinetics of ... [more ▼]

The folding of lysozyme involves parallel events in which hydrogen exchange kinetics indicate the development of persistent structure at very different rates. We have monitored directly the kinetics of formation of the native molecule by the binding of a fluorescently labelled inhibitor, MeU-diNAG (4-methylumbelliferyl-N,N'-diacetyl-beta-D-chitobioside). The data show that native character monitored in this way also develops with different timescales. Although the rate determining step on the slow pathway (similar to 75% of molecules at pH 5.5, 20 degrees C) can be attributed to the need to reorganise structure formed early in the folding process, the data indicate that the rate determining step on the fast track (involving similar to 25% of molecules) involves the docking of the two constituent domains of the protein. In the fast folding track the data are consistent with a model in which each domain forms persistent structure prier to their docking in a locally cooperative manner on a timescale comparable to the folding of small single domain proteins. (C) 1997 Academic Press Limited. [less ▲]

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See detailFast automated extraction and clean-up of biological fluids for polychlorinated dibenzo-p-dioxins, dibenzofurans and coplanar polychlorinated biphenyls analysis
Focant, Jean-François ULg; De Pauw, Edwin ULg

in Journal of Chromatography. B : Analytical Technologies in the Biomedical & Life Sciences (2002), 776(2), 199-212

A fast automated extraction and clean-up procedure for low-level analysis of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (cPCBs ... [more ▼]

A fast automated extraction and clean-up procedure for low-level analysis of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (cPCBs) in biological fluids is presented. Online extraction of prepared fluids is carried out using disposable octadecyl bonded (C-18) solid-phase extraction columns. Extracts are then cleaned up through disposable multi-layer silica (acidic, basic and neutral) and dispersed PX-21 carbon columns. This new methodology is compared with classical Soxhlet extraction and manual solid-phase extraction in terms of repeatability, reproducibility, accuracy and recovery rates for reference and certified materials. Robustness is evaluated on different matrices, such as cow's milk, breast milk and human serum. As a consequence of the reduced number of reusable glassware used, as well as lowering of solvent consumption, recorded blank levels are decreased in favor of limits of detection (LODs). Total analysis time and cost are further reduced using simultaneous sample preparation units and the sample throughput is increased compared to classical methods. As a result, this new approach appears to be suitable for the fast sample preparation often required for such fluids in case of emergency foodstuffs analysis or during large epidemiological studies. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailFast chemical synthesis of [75Se]L-selenomethionine.
Plenevaux, Alain ULg; Cantineau, Robert; Guillaume, Marcel et al

in International Journal of Radiation Applications and Instrumentation. Part A : Applied Radiation and Isotopes (1987), 38(1), 59-61

A fast chemical synthesis of high specific activity [75Se]L-selenomethionine (10 Ci/mmol--370 GBq/mmol) is described with a view to 73Se labeling and PET studies. The overall radiochemical yield of the ... [more ▼]

A fast chemical synthesis of high specific activity [75Se]L-selenomethionine (10 Ci/mmol--370 GBq/mmol) is described with a view to 73Se labeling and PET studies. The overall radiochemical yield of the preparation is better than 80%. The purification method uses commercially available reverse phase HPLC columns and 9% NaCl as mobile phase. The final labeled compound is obtained in less than 3 h and the chemical, radiochemical and optical purities of the L-isomer are higher than 99.0%. [less ▲]

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See detailFast chromatographic method for explosive profiling
Stefanuto, Pierre-Hugues ULg; Peyrrault, Katelynn; Focant, Jean-François ULg et al

Conference (2014, January)

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See detailFast chromatographic method for explosives profiling
Stefanuto, Pierre-Hugues ULg; Perrault, K; Perrault, K et al

in Hyphenated Techniques in Chromatography HTC-13 - Book of abstracts (2014, January)

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See detailFast Clean-up for Polychlorinated Dibenzo-P-Dioxins, Dibenzofurans and Coplanar Polychlorinated Biphenyls Analysis of High-Fat-Content Biological Samples
Focant, Jean-François ULg; Eppe, Gauthier ULg; Pirard, Catherine ULg et al

in Journal of Chromatography. A (2001), 925(1-2), 207-21

A fast clean-up procedure for the low level analysis of polychlorinated dibenzo-p-dioxins. polychlorinated dibenzofurans and coplanar polychlorinated biphenyls in highly fatty biological matrices using ... [more ▼]

A fast clean-up procedure for the low level analysis of polychlorinated dibenzo-p-dioxins. polychlorinated dibenzofurans and coplanar polychlorinated biphenyls in highly fatty biological matrices using high capacity disposable multi-layer silica columns is presented. Results were compared with gel permeation chromatography for removal of lipids. Analytical criteria such as recovery rates, repeatability, reproducibility and robustness are evaluated through a broad range of biological matrices and reference materials analysis. The final proposed procedure for the complete analysis, including pressurized liquid extraction, Power-Prep system clean-up and GC-high-resolution MS analysis requires only 48 h, and allows the simultaneous preparation of up to 10 samples. [less ▲]

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See detailFast Computation of morphological operations with arbitrary structuring elements
Van Droogenbroeck, Marc ULg; Talbot, Hugues

in Pattern Recognition Letters (1996), 17(14), 1451-1460

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See detailFast contingency filtering based on linear voltage drop estimates
Otomega, Bogdan; Van Cutsem, Thierry ULg

(2005, June)

This paper deals with the filtering of harmless contingencies in voltage stability and security analyses. In many systems, a post-contingency load flow allows to identify the contingencies with severe ... [more ▼]

This paper deals with the filtering of harmless contingencies in voltage stability and security analyses. In many systems, a post-contingency load flow allows to identify the contingencies with severe impact on voltage stability, as causing either divergence or large voltage drops. However, for filtering purposes, accurate voltage drops need not be computed; linear estimates obtained from sensitivity formulas are appropriate. For a given contingency, the method used in this paper solves a sparse linear system to update the phase angles, assuming constant voltage magnitudes. Then, assuming constant active power flows in the branches, a second sparse system is solved to update the voltage magnitudes. This yields better accuracy than one full load flow iteration while retaining the sparse structure of a decoupled formulation. For contingency analysis, the incidents are filtered by comparing the voltage drops to a threshold. For secure power margin computations, the same procedure is used after stressing the system in the specified direction. The method has been tested on a real system where it has been found to combine simplicity of implementation, quality of filtering and computational efficiency. [less ▲]

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See detailFast controlled radical polymerization of styrene mediated by oligomeric nitroxides formed in situ
Sciannamea, Valérie; Catala, Jean-Marie; Jérôme, Robert ULg et al

in Macromolecular Rapid Communications (2007), 28(2), 147-151

In the presence of an oligomeric hindered secondary amine added with peracetic acid as the oxidant, radical polymerization of styrene is fast and controlled at 110 degrees C. Under these experimental ... [more ▼]

In the presence of an oligomeric hindered secondary amine added with peracetic acid as the oxidant, radical polymerization of styrene is fast and controlled at 110 degrees C. Under these experimental conditions, an oligomeric nitroxide is formed in situ. This polymerization is 2.5 faster than polymerization mediated by the alkoxyamine derivated from TIPNO (2,2,5-trimethyl-4- phenyl-3-azahexane-3-nitroxide), which generates a low molar mass nitroxide. Similarly, substitution of a low molar mass secondary amine, 2,2,6, 6-tetramethylpiperidone (4-oxo-TMP), for the oligomeric secondary amine maintains the control on the polymerization, which is however 4.6 times slower, all the other conditions being the same. The in situ formation of the oligomeric nitroxide has been confirmed by electron spin resonance (ESR). [less ▲]

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See detailFast core rotation in red-giant stars as revealed by gravity-dominated mixed modes
Beck, Paul G; Montalban Iglesias, Josefa ULg; Kallinger, Thomas et al

in Nature (2012), 481

When the core hydrogen is exhausted during stellar evolution, the central region of a star contracts and the outer envelope expands and cools, giving rise to a red giant. Convection takes place over much ... [more ▼]

When the core hydrogen is exhausted during stellar evolution, the central region of a star contracts and the outer envelope expands and cools, giving rise to a red giant. Convection takes place over much of the star's radius. Conservation of angular momentum requires that the cores of these stars rotate faster than their envelopes; indirect evidence supports this. Information about the angular-momentum distribution is inaccessible to direct observations, but it can be extracted from the effect of rotation on oscillation modes that probe the stellar interior. Here we report an increasing rotation rate from the surface of the star to the stellar core in the interiors of red giants, obtained using the rotational frequency splitting of recently detected `mixed modes'. By comparison with theoretical stellar models, we conclude that the core must rotate at least ten times faster than the surface. This observational result confirms the theoretical prediction of a steep gradient in the rotation profile towards the deep stellar interior. [less ▲]

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See detailFast determination of myoglobin in serum using a new radial partition immunoassay
Chapelle, Jean-Paul ULg; Lemache, K.; el Allaf, M. et al

in Clinical Biochemistry (1994), 27(5), 423-8

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See detailFast double antibody radioimmunoassay of human granulocyte myeloperoxidase and its application to plasma.
Pincemail, Joël ULg; Deby-Dupont, G.; Deby, Christiane ULg et al

in Journal of Immunological Methods (1991), 137(2), 181-191

The haem enzyme myeloperoxidase (MPO) (EC 1.11.1.7) with a spectral A430/A280 ratio greater than 0.7 and a specific activity of 125 U/mg was purified from isolated human neutrophils. To obtain a ... [more ▼]

The haem enzyme myeloperoxidase (MPO) (EC 1.11.1.7) with a spectral A430/A280 ratio greater than 0.7 and a specific activity of 125 U/mg was purified from isolated human neutrophils. To obtain a radioimmunoassay (RIA) for this enzyme, a specific antiserum against human neutrophil MPO was raised in rabbits and used at an initial dilution of 1/10,000. MPO labelled with 125iodine by a technique of self-labelling in the presence of H2O2, had a specific activity of 24 mCi/mg. After incubation at room temperature (2 h) and separation by double antibody precipitation in the presence of polyethylene glycol, the sensitivity of the RIA was 21 ng/ml. The RIA showed good precision and accuracy with intra- and interassay coefficients of variation of less than 7% for MPO concentrations ranging from 100 to 800 ng/ml, and satisfactory recoveries of known amounts of exogenous MPO in plasma. For the measurement of MPO in blood, the best sampling technique was to collect blood into EDTA. Rapid centrifugation (within 20 min) was necessary for blood collected into heparin. Mean MPO values in normal individuals were 340 +/- 98 ng/ml in EDTA plasma (n = 152) and 332 +/- 82 ng/ml in heparinized plasma (n = 34). When MPO was measured 12-6 h after injury in critically ill patients high values (above 1000 ng/ml) were found in 6/15 patients with multiple injuries. In patients with sepsis (n = 22), MPO values were always above 1000 ng/ml. [less ▲]

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See detailFast F-18 FDG synthesis by alkaline hydrolysis on a low polarity solid phase supports
Lemaire, Christian ULg; Damhaut, P.; Lauricella, Benjamino ULg et al

in Journal of Labelled Compounds & Radiopharmaceuticals (2002), 45(5), 435-447

The synthesis of 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) has been simplified by the use of a tC18 Sep Pak cartridge to effect purification and hydrolysis of the tetraacetylated [18F]fluoro-glucose ... [more ▼]

The synthesis of 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) has been simplified by the use of a tC18 Sep Pak cartridge to effect purification and hydrolysis of the tetraacetylated [18F]fluoro-glucose compound ([18F]TAG). After radiolabelling, this derivative was trapped on a solid phase extraction (SPE) cartridge and the residual reaction solvent (CH3CN), reagents (K222, K2CO3,) and by-products removed by washing the support with water. After this cleaning step, the acetyl groups were cleaved on the same tC18 column using 2N sodium hydroxide. This fast reaction proceeded near quantitatively (>98%) at room temperature in less than 2 min. The [18F]FDG was then recovered with a small amount of water, neutralized with a slight excess of 2N hydrochloric acid, buffered for pH with a citrate solution and finally purified on a neutral alumina oxide and a second tC18 column. After filtration, the radiochemical yield of this [18F]FDG isotonic solution after more than 100 production runs was found to be very reliable and reproducible (70±6% decay corrected). The synthesis time was about 22 min. Quality controls showed that the radiochemical purity was higher than 98% and in any case no [18F]FDM was detected. Only traces of 2-chloro-2-deoxy-glucose (ClDG) were found in the final sample (64±9 g/ batch of 16 ml). [18F]FDG specific activity averaged between 1 and 20 Ci/µmol (EOS). No evaporation and use of ion retardation resin (AG11A8) are required. Moreover, this new approach is suitable for complete remote operation using available single use medical components. Copyright © 2002 John Wiley [less ▲]

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See detailFast freezing of cow embryos in French straws with an automatic program.
Massip, A.; Van der Zwalmen, P.; Hanzen, Christian ULg et al

in Theriogenology (1982), 18(3), 325-332

Cow embryos between day 6.5 and 9 were frozen in 1.5M DMSO in PBS at 2 degrees C/min from seeding to -25 degrees C before being plunged into liquid nitrogen directly or after 10 min at -25 degrees C ... [more ▼]

Cow embryos between day 6.5 and 9 were frozen in 1.5M DMSO in PBS at 2 degrees C/min from seeding to -25 degrees C before being plunged into liquid nitrogen directly or after 10 min at -25 degrees C. Cooling rate from 20 degrees C to -5 degrees C was 9 degrees C/min. Seeding was induced automatically at -5 degrees C by injection of liquid nitrogen vapour. Embryos were subsequently thawed by direct transfer to water at 20 degrees C (group I) or at 37 degrees C (group II). Survival was assessed by culture in vitro and by transfer. In group I, 35.7% were degenerated after thawing (compared to 35.4% in group II). Survival rate after culture in vitro for 24h was not significantly different (48.3% vs 42.8%) and hatching rate after 96h culture was quite similar (33.3% vs 34.4%). In group II, four pregnancies were obtained from 10 embryos transferred. Time at -25 degrees C did not improve the results. Automatic seeding did not impair survival. These results show that the quality of the embryo is the determinant factor for survival after freezing and that the plastic straw is the most suitable vessel for freezing, storage and transfer of embryos. [less ▲]

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See detailA fast gas chromatographic method for the study of semiochemical slow release formulations
Heuskin, Stéphanie ULg; Lorge, Stéphanie; Leroy, Pascal ULg et al

Poster (2010, January)

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See detailFast gas-phase hydrogen/deuterium exchange observed for a DNA G-quadruplex
Gabelica, Valérie ULg; Rosu, Frédéric ULg; Witt, Matthias et al

in Rapid Communications in Mass Spectrometry : RCM (2005), 19(2), 201-208

The gas-phase hydrogen/deuterium (H/D) exchange kinetics of DNA G-quadruplexes has been investigated using Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). The quadruplex [(TGGGGT)(4 ... [more ▼]

The gas-phase hydrogen/deuterium (H/D) exchange kinetics of DNA G-quadruplexes has been investigated using Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). The quadruplex [(TGGGGT)(4).3NH(4)(+)] undergoes very fast H/D exchange, in both the positive and in the negative ion modes, compared to DNA duplexes and other quadruplexes tested, and compared to the corresponding single-stranded TGGGGT. Substitution of NH4+ for K+ did not alter this fast H/D exchange, indicating that the hydrogens of the ammonium ions are not those exchanged. However, stripping of the interior cations of the quadruplex by source collision-induced dissociation (CID) in the positive ion mode showed that the presence of the inner cations is essential for the fast exchange to be possible. Molecular dynamics simulations show that the G-quadruplex is very rigid in the gas phase with NH4+ ions inside the tetrads. We suggest that the fast H/D exchange is favored by this rigid quadruplex conformation. This example illustrates that the concept that compact DNA structures exchange H for D slower than unfolded ones is a misconception. Copyright (C) 2004 John Wiley Sons, Ltd. [less ▲]

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