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See detailDirect multiple-point geostatistical simulation of edge properties for modeling thin irregularly-shaped surfaces
Huysmans, Marijke; Dassargues, Alain ULg

in Cockx, L.; Van Meirvenne, M.; Bogaert, P. (Eds.) et al 8th International Conference On Geostatistics for Environmental Applications, GeoENV’2010 (2010, September)

Thin irregularly-shaped surfaces such as clay drapes often have a major control on flow and transport in heterogeneous porous media. Clay drapes are often complex curvilinear 3-dimensional surfaces and ... [more ▼]

Thin irregularly-shaped surfaces such as clay drapes often have a major control on flow and transport in heterogeneous porous media. Clay drapes are often complex curvilinear 3-dimensional surfaces and display a very complex spatial distribution. Variogram-based stochastic approaches are often also not able to describe the spatial distribution of clay drapes since complex, curvilinear, continuous and interconnected structures cannot be characterized using only two-point statistics. Multiple-point geostatistics aims to overcome the limitations of the variogram. The premise of multiple-point geostatistics is to move beyond two-point correlations between variables and to obtain (cross) correlation moments at three or more locations at a time using "training images" to characterize the patterns of geological heterogeneity. Multiple-point geostatistics is able to reproduce thin irregularly-shaped surfaces such as clay drapes but is often computationally intensive. To capture the thin surfaces, a small grid cell size should be adopted for the training image. This results in large training images and a large search template size and thus a large CPU and RAM demand (Huysmans and Dassargues, 2009). [less ▲]

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See detailDirect n.m.r. evidence for substrate-induced conformational changes in a beta-lactamase.
Jamin, M.; Damblon, Christian ULg; Bauduin-Misselyn, A. M. et al

in Biochemical Journal (1994), 301 ( Pt 1)

Cefoxitin and other beta-lactam antibiotics with a methoxy group on the alpha-face behave as very poor substrates of the Bacillus licheniformis beta-lactamase. The kinetic properties of the enzyme ... [more ▼]

Cefoxitin and other beta-lactam antibiotics with a methoxy group on the alpha-face behave as very poor substrates of the Bacillus licheniformis beta-lactamase. The kinetic properties of the enzyme-cefoxitin system made it theoretically suitable for a detailed structural study of the acyl-enzyme. Unfortunately, soaking the crystals in cefoxitin solution did not allow detection of a crystalline acyl-enzyme complex. In contrast, direct observation by n.m.r. of the stable acyl-enzyme formed with cefoxitin and moxalactam indicated clear modifications of the enzyme structure, which were reflected in the aromatic and high-field methyl regions of the spectrum. The return to the initial free enzyme spectrum was concomitant with the hydrolysis of the acyl-enzyme, the process being slow enough to allow multidimensional n.m.r. experiments. [less ▲]

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See detailDirect nano-in-micropatterning of TiO2 thin layers and TiO2/Pt nanoelectrode arrays by deep X-ray lithography
Faustini, M.; Marmiroli, B.; Malfatti, L. et al

in Journal of Materials Chemistry (2011), 21

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See detailDirect NMR evidence for a local resriction in the segmental chain mobility of a model ionomer
Vanhoorne, Pierre; Jérôme, Robert ULg; Teyssié, Philippe et al

in Macromolecules (1994), 27(9), 2548-2552

To probe the local mobility of the chain segments directly attached to ionic multiplets, two model ionomers have been synthesized. The first one is a carboxylato-telechelic deuterated polystyrene in which ... [more ▼]

To probe the local mobility of the chain segments directly attached to ionic multiplets, two model ionomers have been synthesized. The first one is a carboxylato-telechelic deuterated polystyrene in which the chain segments bearing the sodium carboxylate end groups have been selectively protonated; the second one has a protonated polystyrene backbone terminated at both ends with a deuterated polystyrene segment bearing the sodium carboxylate groups. Both polymers have been studied by high-resolution solid-state C-13 NMR. Line-width measurements of the protonated units have clearly shown that the dipolar interactions of the sodium carboxylate end groups are responsible for a mobility restriction of the chain end segments. This experiment is thought to be the first direct evidence for the model recently proposed by Eisenberg et al. for ionomer morphology according to which the ionic multiplets are surrounded with a shell of constrained polymer segments. [less ▲]

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See detailDirect Numerical Simulation of Mixed Convection in Turbulent Channel Flow: On the Reynolds number dependency of momentum and heat transfer under unstable stratification
Sid, Samir ULg; Dubief, Yves; Terrapon, Vincent ULg

in Proceedings of the 8th International Conference on Computational Heat and Mass Transfer, ICCHMT 2015 (2015, May 27)

Direct numerical simulations of unstably stratified turbulent channel flow have been performed in order to investigate the Reynolds number effect on mixed convection. Six different cases are considered ... [more ▼]

Direct numerical simulations of unstably stratified turbulent channel flow have been performed in order to investigate the Reynolds number effect on mixed convection. Six different cases are considered with friction Reynolds number Re_\tau =180 and 395 and friction Richardson number Ri_\tau = 0, 100 and 1000. It is shown that both friction coefficient and Nusselt number increase under unstable stratification for a sufficiently large Richardson number. At low Richardson number, the friction coefficient can either increase or decrease depending on the Reynolds number. The drag reduction is associated with an increase of mean velocity due to an enhanced dissipation of Reynolds shear stress by pressure strain in the buffer region. The breakdown of the Reynolds analogy is demonstrated as the turbulent Prandtl number exhibits a non-constant behavior due to buoyancy. [less ▲]

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See detailDirect observation of microdomain morphology in "all-acrylic" thermoplastic elastomers synthesized via living radical polymerization
Leclère, Philippe; Moineau, Georges; Minet, Michaël et al

in Langmuir (1999), 15(11), 3915-3919

We investigate the microscopic morphology of thin films of symmetric triblock copolymers synthesized via a two-step “living” radical polymerization of n-butylacrylate and methyl methacrylate. These ... [more ▼]

We investigate the microscopic morphology of thin films of symmetric triblock copolymers synthesized via a two-step “living” radical polymerization of n-butylacrylate and methyl methacrylate. These copolymers with low poly(methyl methacrylate) contents constitute a new class of potential thermoplastic elastomers with higher service temperature and oxidation resistance compared to conventional polydiene−polystyrene-based thermoplastic elastomers. The straightforward synthetic pathway allows for strict control of molecular weight, molecular-weight distribution, and composition. The presence in the copolymer of immiscible segments covalently bound to each other leads to phase separation on the nanometer scale. Regular organization of the phase-separated nanodomains is observed in real space by scanning force microscopy. The data point to a strong contrast in the local mechanical properties, corresponding to the microphase morphology. Cylinders of the minority phase are found to orient perpendicular to the surface, because of the surface energy difference between the constituents. Lamellae are also arranged perpendicular to the surface, in contrast to what is usually observed in block copolymers. This particular orientation is thought to result from the symmetric character of these triblock systems, with the outer blocks more polar than the central sequence. [less ▲]

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See detailDirect observation of the depairing current density in single-crystalline Ba0.5K0.5Fe2As2 microbridge with nanoscale thickness
Li, Jun; Yuan, Jie; Yuan, Ya-Hua et al

in Applied Physics Letters (2013), 103

We investigated the critical current density (Jc) of Ba0.5K0.5Fe2As2 single-crystalline microbridges with thicknesses ranging from 276 to 18 nm. The Jc of the microbridge with thickness down to 91 nm is ... [more ▼]

We investigated the critical current density (Jc) of Ba0.5K0.5Fe2As2 single-crystalline microbridges with thicknesses ranging from 276 to 18 nm. The Jc of the microbridge with thickness down to 91 nm is 10.8 MA/cm2 at 35 K, and reaches 944.4 MA/cm2 by extrapolating Jc(T) to T = 0 K using a two-gap s-wave Ginzburg-Landau model, well in accordance with the depairing current limit. The temperature, magnetic field, and angular-dependence of Jc(T,H,q) indicated weaker field dependence and weakly anisotropic factor of 1.15 (1 T) and 1.26 (5 T), which also yielded the validity of the anisotropic Ginzburg-Landau scaling. [less ▲]

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See detailDirect observations of surface water-groundwater interaction using electrical resistivity tomography
Noell, U.; Wießner, C.; Ganz, C. et al

in IAHS-AISH Publication (2011)

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See detailDirect one-pot synthesis of poly(ionic liquid) nanogels by cobalt-mediated radical cross-linking copolymerization in organic or aqueous media
Weiss-Maurin, Mathilde ULg; Cordella, Daniela ULg; Jérôme, Christine ULg et al

in Polymer Chemistry (2016), 7(14), 2521-2530

Nanogels of controlled kinetic chain length were synthesized by cobalt-mediated radical cross-linking copolymerization (CMRccP) involving a vinyl monomer and a divinyl cross-linker. This strategy was ... [more ▼]

Nanogels of controlled kinetic chain length were synthesized by cobalt-mediated radical cross-linking copolymerization (CMRccP) involving a vinyl monomer and a divinyl cross-linker. This strategy was first validated to achieve neutral poly(vinyl acetate) nanogels by CMRccP of vinyl acetate and divinyl adipate as cross-linker, at 40 °C, in presence of an alkyl- cobalt(III) serving both as initiator and controlling agent, using ethyl acetate as solvent. Poly(ionic liquid) nanogels were then directly obtained by CMRccP of N-vinyl-3-ethyl imidazolium bromide, in presence of 1,13-divinyl-3-decyl diimidazolium bromide as cross-linker. CMRccP experiments could be conducted either in organic solvent using dimethyl formamide or, more interestingly, in aqueous solution, demonstrating the robustness and the versatility of this one-step process. Chain extensions of PILs nanogels were also carried out in water, forming core-shell structures, thus opening new avenues in the design of functional nanogels. [less ▲]

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See detailDirect parameter identification in a model of the cardiovascular system
Pironet, Antoine ULg; Dauby, Pierre ULg; Desaive, Thomas ULg

in 11th Belgian Day on Biomedical Engineering (2012, December 07)

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See detailDirect prediction of spatially and temporally varying physical properties from time-lapse electrical resistance data
Hermans, Thomas ULg; Oware, Erasmus; Caers, Jef

in Water Resources Research (2016), 52

Time-lapse applications of electrical methods have grown significantly over the last decade. However, the quantitative interpretation of tomograms in terms of physical properties, such as salinity ... [more ▼]

Time-lapse applications of electrical methods have grown significantly over the last decade. However, the quantitative interpretation of tomograms in terms of physical properties, such as salinity, temperature or saturation, remains difficult. In many applications, geophysical models are transformed into hydrological models, but this transformation suffers from spatially and temporally varying resolution resulting from the regularization used by the deterministic inversion. In this study, we investigate a prediction-focused approach (PFA) to directly estimate subsurface physical properties with electrical resistance data, circumventing the need for classic tomographic inversions. First, we generate a prior set of resistance data and physical property forecast through hydrogeological and geophysical simulations mimicking the field experiment. We reduce the dimension of both the data and the forecast through principal component analysis in order to keep the most informative part of both sets in a reduced dimension space. Then, we apply canonical correlation analysis to explore the relationship between the data and the forecast in their reduced dimension space. If a linear relationship can be established, the posterior distribution of the forecast can be directly sampled using a Gaussian process regression where the field data scores are the conditioning data. In this paper, we demonstrate PFA for various physical property distributions. We also develop a framework to propagate the estimated noise level in the reduced dimension space. We validate the results by a Monte Carlo study on the posterior distribution and demonstrate that PFA yields accurate uncertainty for the cases studied. [less ▲]

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See detailDirect quantitative analysis of linamarin in cassava by high performance thin-layer chromatography
Bodart, Patricia; Muzembe, K. F.; Penelle, Jacques et al

Conference (1997, April)

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See detailDirect Quantitative Analysis of Linamarin in Cassava by High-Performance Thin Layer Chromatography
Bodart, Patricia; Penelle, Jacques; Angenot, Luc ULg et al

in Journal of Planar Chromatography- Modern TLC (1998), 11(January/February), 38-42

A simple, rapid and accurate HPTLC quantitative procedure is presented for the direct determination of linamarin. A cassava sample was extracted with boiling 80% v/v methanol and the extract and linamarin ... [more ▼]

A simple, rapid and accurate HPTLC quantitative procedure is presented for the direct determination of linamarin. A cassava sample was extracted with boiling 80% v/v methanol and the extract and linamarin were applied to silicagel HPTLC plates prewashed by development with methanol.The plates were first developed to a distance of 30mm with ethyl acetate-acetone-water, 40+50+10 (v/v), then to a distance of 85 mm with ethyl acetate-formic acid-water, 60+10+10 (v/v). the spots were visualized by dipping the plate into a solution af aniline (2%), and phosphoric acid 15% in acetone, then heating at 105°C for 60 min. Densitometric quantification was effected at lambda= 525 nm by transmission scanning. The method was validated for accuracy, intraday, and interday reproducibility of peak area, linearity, and detection limit. [less ▲]

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See detailDirect regeneration of rattan seedlings from apical meristem and axillary bud explants
Kouakou, L. K.; Zoro Bi, I. A.; Kouakou, T. H. et al

in Belgian Journal of Botany (2009), 142(1), 60-67

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See detailDirect responses to six generations of selection for ovulation rate or prenatal survival in Large White pigs.
Rosendo, A.; Druet, Tom ULg; Gogue, J. et al

in Journal of Animal Science (2007), 85(2), 356-64

Effects of selection for ovulation rate or prenatal survival were examined using data from 3 pigs lines derived from the same base Large White population. Two lines were selected for 6 generations on high ... [more ▼]

Effects of selection for ovulation rate or prenatal survival were examined using data from 3 pigs lines derived from the same base Large White population. Two lines were selected for 6 generations on high ovulation rate at puberty (OR line) or high prenatal survival corrected for ovulation rate in the first 2 parities (PS line). The third line was an unselected control line. Genetic parameters for ovulation rate on the left, right, and both ovaries at puberty (ORPL, ORPR, and ORP, respectively) and at fertilization (ORFL, ORFR, and ORF, respectively), total number of piglets born (TNB) per litter, prenatal survival (PS = TNB/ORF), and PS corrected for ovulation rate (CPS = PS + 0.018ORF) were estimated using REML methodology. Responses to selection were estimated by computing differences between OR or PS and control lines at each generation using least squares and mixed models methodology. Average genetic trends were computed by regressing line differences on generation number. Realized heritabilities were estimated using standard procedures. Heritability estimates were 0.17, 0.11, 0.34, 0.13, 0.09, 0.33, 0.14, 0.11, and 0.17 (SE = 0.01 to 0.03) for ORPL, ORPR, ORP, ORFL, ORFR, ORF, PS, CPS, and TNB, respectively. Realized heritabilities were 0.37 +/- 0.08 and 0.10 +/- 0.09 for ORP and CPS, respectively. The different measures of ovulation rate had strong genetic correlations (r(g) > 0.7). The ORF had midrange negative genetic correlations with PS and CPS (-0.45 +/- 0.07 and -0.42 +/- 0.08, respectively). The ORP also had an antagonistic genetic relationship with PS (-0.26 +/- 0.07) but was almost independent from CPS (-0.02 +/- 0.11). The TNB was moderately correlated with ORP and ORF (r(g) = 0.41 +/- 0.09 for both traits). Average genetic trends in OR and PS lines were, respectively, 0.49 +/- 0.10 and 0.11 +/- 0.10 for ORP, and 0.43 +/- 0.11 and 0.11 +/- 0.11 for ORF. Responses to selection were slightly superior in the left than in the right ovary. No significant difference was found for PS or CPS in any of the lines. The TNB did not change in the OR line but significantly improved in the PS line (0.24 +/- 0.11 piglets/generation). [less ▲]

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See detailDirect route to well-defined poly(ionic liquid)s by controlled radical polymerization in water
Cordella, Daniela ULg; Kermagoret, Anthony ULg; Debuigne, Antoine ULg et al

in ACS Macro Letters (2014), 3

The precision synthesis of poly(ionic liquid)s (PILs) in water is achieved for the first time by the cobalt-mediated radical polymerization (CMRP) of N-vinyl-3-alkylimidazolium-type monomers following two ... [more ▼]

The precision synthesis of poly(ionic liquid)s (PILs) in water is achieved for the first time by the cobalt-mediated radical polymerization (CMRP) of N-vinyl-3-alkylimidazolium-type monomers following two distinct protocols. The first involves the CMRP of various 1-vinyl-3-alkylimidazolium bromides conducted in water in the presence of an alkyl–cobalt(III) complex acting as a monocomponent initiator and mediating agent. Excellent control over molar mass and dispersity is achieved at 30 °C. Polymerizations are complete in a few hours, and PIL chain-end fidelity is demonstrated up to high monomer conversions. The second route uses the commercially available bis(acetylacetonato)cobalt(II) (Co(acac)2) in conjunction with a simple hydroperoxide initiator (tert-butyl hydroperoxide) at 30, 40, and 50 °C in water, facilitating the scaling-up of the technology. Both routes prove robust and straightforward, opening new perspectives onto the tailored synthesis of PILs under mild experimental conditions in water. [less ▲]

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See detailDirect social costs of osteoporotic hip fractures in Belgium
Gillet, Pierre ULg; Reginster-Haneuse, G; Reginster, Jean-Yves ULg

in Osteoporosis International (1996), 6(S1), 119

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See detailDirect social costs of Osteoporotice hip fractures in Belgium
Gillet, Pierre ULg; Gosset, Christiane ULg; Reginster, Jean-Yves ULg

in Calcified Tissue International (1997), 61

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See detailDirect stimulation of cytokines (IL-1 beta, TNF-alpha, IL-6, IL-2, IFN-gamma and GM-CSF) in whole blood. I. Comparison with isolated PBMC stimulation.
De Groote, D.; Zangerlé, Pierre-François ULg; Gevaert, Y. et al

in Cytokine (1992), 4(3), 239-48

Production of interleukin 1 beta (IL-1 beta), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), interleukin 2 (IL-2), interferon gamma (IFN-gamma) and granulocyte-macrophage colony ... [more ▼]

Production of interleukin 1 beta (IL-1 beta), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), interleukin 2 (IL-2), interferon gamma (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF) after stimulation by lipopolysaccharide (LPS) and phytohemagglutinin (PHA) was studied in 1/10 diluted whole blood (WB) culture and in peripheral blood mononuclear cell (PBMC) culture. Cytokines IL-1 beta, TNF-alpha and IL-6 are preferentially stimulated by LPS whereas IL-2, IFN-gamma and GM-CSF are stimulated by PHA. Combination of 5 micrograms/ml PHA and 25 micrograms/ml LPS gave the most reliable production of the six cytokines studied. IL-1 beta, TNF-alpha and IL-6 represent a homogeneous group of early-produced cytokines positively correlated among themselves and with the number of monocytes in the culture (LeuM3). Furthermore, IL-1 beta was negatively correlated with the number of T8 lymphocytes. IL-2, IFN-gamma and GM-CSF represent a group of late-produced cytokines. Kinetics and production levels of IL-6 and GM-CSF are similar in WB and PBMC cultures. In contrast, production levels of TNF-alpha and IFN-gamma are higher in WB than in PBMC whereas production levels of IL-6 and IL-2 are lower in WB than in PBMC. Individual variation in responses to PHA + LPS was always higher in PBMC cultures than in WB cultures. The capacity of cytokine production in relation to the number of mononuclear cells is higher in WB, or in PBMC having the same mononuclear cell concentration as WB, than in conventional cultures of concentrated PBMC (10(6)/ml). Because it mimics the natural environment, diluted WB culture may be the most appropriate milieu in which to study cytokine production in vitro. [less ▲]

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