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See detailDensitometric Determination of Salicin in Willow Stem Bark
Poukens-Renwart, Pascale; Tits, Monique ULg; Angenot, Luc ULg

in Journal of Planar Chromatography (1993), 6(november-december), 434-437

Most of the salicin present in willow stem bark occurs as labile glycosides (e.g. salicin, salicortin, 2-O'-acetylsalicortin, 3-O'-acetylsalicortin, tremulacin and fragilin). On alkaline hydrolysis, these ... [more ▼]

Most of the salicin present in willow stem bark occurs as labile glycosides (e.g. salicin, salicortin, 2-O'-acetylsalicortin, 3-O'-acetylsalicortin, tremulacin and fragilin). On alkaline hydrolysis, these acylated derivatives decompose to salicin; in this way, the total amount of salicin can be determined. A HPTLC method has been developed for the quantitative determination of salicin in stem bark before and after alkaline hydrolysis. The mobile phase used for the separation is a modification of one described in the literature. a double or triple migration is necessary to separate salicin from other components of the extract. The results have been compared with those obtained after bidimensional chromatography using two phases described for the quantitative evaluation of salicin. to check that separation was complete, the spectrum of salicin obtained from willow extracts was superimposed on that of a salicin standard.Quantification was performed at lambda = 270nm, the wavelenght of maximum absorption in the IV spectrum of salicin. [less ▲]

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See detailDensitometric Evaluation of fraxin in leaves of Fraxinus excelsior
Poukens-Renwart, Pascale; Tits, Monique ULg; Wauters, Jean-Noël ULg et al

in Journal de Pharmacie de Belgique (1992), 47(3), 241

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See detailDensitometric evaluation of fraxin in leaves of Fraxinus excelsior
Poukens-Renwart, Pascale; Tits, Monique ULg; Wauters, Jean-Noël ULg et al

Poster (1992, May)

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See detailDensitometric Evaluation of Gentiopicroside in the Roots of Gentiana lutea L.
Bodart, Patricia; Poukens-Renwart, Pascale; Wauters, Jean-Noël ULg et al

in Journal of Planar Chromatography- Modern TLC (1996), 9(March/April), 143-145

As no satisfactory method existed for the separation of gentiopicroside from other components of gentian roots, we have decided to undertake some experiments.In this communication, we report the use of a ... [more ▼]

As no satisfactory method existed for the separation of gentiopicroside from other components of gentian roots, we have decided to undertake some experiments.In this communication, we report the use of a novel mobile phase and a different detection system. Our HPTLC method is a fast and reliable procedure which may be used for quantification of gentiopicroside in roots and extracts of Gentiana lutea, whether for routine analysis or for studying stability. The TLC method is also compared with an HPLC method. [less ▲]

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See detailDensitometric Evaluation of Spiraeoside after Derivatization in Flowers of Filipendula Ulmaria (L.) Maxim
Poukens-Renwart, P.; Tits, Monique ULg; Wauters, Jean-Noël ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (1992), 10(10-12, Oct-Dec), 1085-8

Spiraeoside (quercetin-4'-glucoside) is the major and most caharacteristic flavonoid of Filipendula ulmaria flowers and is not found in the leaves and stems. This paper describes a quantification of ... [more ▼]

Spiraeoside (quercetin-4'-glucoside) is the major and most caharacteristic flavonoid of Filipendula ulmaria flowers and is not found in the leaves and stems. This paper describes a quantification of spiraeoside by HPTLC densitometry after derivatization with diphenylboric acid -2-aminoester. The fluorescence of this flavonoid was measured at 330 nm. the spiraeoside content in batches of Filipendula ulmaria flowers ranged from 3 to 4.3 %. It is of note that these results are similar to those published elsewhere after HPLC analysis of other batches. [less ▲]

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See detailDensitometric evaluation of spiraeoside after derivatization in flowers of Filipendula ulmaria (L.) Maxim.
Poukens-Renwart, Pascale; Tits, Monique ULg; Wauters, Jean-Noël ULg et al

Poster (1992, September)

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See detailDensitometric evaluation of spiraeoside in Filipendula ulmaria flowers after derivatization
Poukens-Renwart, Pascale; Tits, Monique ULg; Wauters, Jean-Noël ULg et al

Poster (1992)

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See detailA Densitometric Method for the Determination of Three Clinically Important Monosaccharides in Urine
Poukens-Renwart, Pascale; Angenot, Luc ULg

in Journal of Planar Chromatography (1991), 4(January/February), 77-79

A quantitative, densitometric, thin layer chromatographic method has been developed for the determination of three clinically important monosaccharides in ureine, after desalting.The analysis of these ... [more ▼]

A quantitative, densitometric, thin layer chromatographic method has been developed for the determination of three clinically important monosaccharides in ureine, after desalting.The analysis of these monosaccharides in urine allows to observe the potential changes induced by antiinflammatories in human small intestine permeability. Xylose, 3-O-methylglucose and rhamnose were estimated quantitatively in urine; arabinose was used as internal standard. The densitometry was performed at a wavelenght of 400 nm after a visualization reaction on HPTLC plates. In all cases, coefficients of variation of the method were less than 2.7%. [less ▲]

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See detailDensity and porosity control of sintered 316L stainless steel parts produced by additive manufacturing
Verlee, Bruno; Dormal, Thierry ULg; Lecomte-Beckers, Jacqueline ULg

in Powder Metallurgy (2012), 55(4), 260-267

Additive manufacturing (AM) techniques offer the possibility to build complex geometries with integrated functionalities. Three-dimensional (3D) printing of metallic powder is probably the only AM ... [more ▼]

Additive manufacturing (AM) techniques offer the possibility to build complex geometries with integrated functionalities. Three-dimensional (3D) printing of metallic powder is probably the only AM technique that can build controlled porosity sintered parts, such as filter elements and fluid permeable components. Many building and sintering parameters can be set to adjust porous properties of the final part. The effects of particle size, paricul shape, sintering temperature and sintering time on the final properties of the sinteres parts have been analysed. Correlations have been established between these properties and process parameters [less ▲]

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See detailDensity estimates and nesting-site selection in chimpanzees of the Nimba Mountains, Côte d'Ivoire and Guinea
Granier, Nicolas ULg; Hambuckers, Alain ULg; Matsuzawa et al

in American Journal of Primatology (2014)

We investigated nesting behavior of non habituated chimpanzees populating the Nimba Mountains to document their abundance and their criterions of nesting-site selection. During a 19-month study we walked ... [more ▼]

We investigated nesting behavior of non habituated chimpanzees populating the Nimba Mountains to document their abundance and their criterions of nesting-site selection. During a 19-month study we walked 80 km of transects and recces each month, and recorded 764 nests (mean group size = 2.23 nests) along with characteristics of vegetation structure and composition, topography and seasonality. Population density estimated with two nest count methods ranged between 0.14 and 0.65 chimpanzee/km2. These values are lower than previous estimates, emphasizing the necessity of protecting remaining wild ape populations. Chimpanzees built nests in 108 tree species out of 437 identified, but 2.3% of total species comprised 52% of nests. Despite they preferred nesting in trees of 25-29 cm DBH and at a mean height of 8.02 m, we recorded an important proportion of terrestrial nests (8.2%) that may reflect a cultural trait of Nimba chimpanzees. A logistic model of nest presence formulated as a function of 12 habitat variables revealed preference for gallery and mountain forests rather than lowland forest, and old-growth forest rather than secondary forests. They nested more frequently in the study area during the dry season (December-April). The highest probability of observing nests was at 770 m altitude, particularly in steep locations (mean ground declivity = 15.54%). Several of the reported nest characteristics combined with the existence of 2 geographically separated clusters of nest, suggest that the study area constitutes the non-overlapping peripheral areas of 2 distinct communities. This nest-based study led us to findings on the behavioral ecology of Nimba chimpanzees, which constitute crucial knowledge to implement efficient and purpose-built conservation. [less ▲]

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See detailDensity Functional Perturbation Theory
Verstraete, Matthieu ULg; Zanolli, Zeila; Blügel, S. et al

in Computing Solids: Models, Ab-initio Methods and Supercomputing, Lecture Notes of the 45th Spring School 2014 (2014)

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See detailDensity Functional Perturbation Threory with Spin-Orbit Coupling: the case of Pb
Verstraete, Matthieu ULg; Torrent, M.; Jollet, F. et al

in Physical Review. B : Condensed Matter (2008), 78

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See detailA density functional theory calculation of the electronic properties of several high-spin and low-spin iron(II) pyrazolylborate complexes
Remacle, Françoise ULg; Long, G. J.; Grandjean, Fernande ULg

in Inorganic Chemistry (2008), 47(10), 4005-4014

Density functional theory has been used to study the electronic spin-state properties of low-spin Fe[HB(PZ)(3)](2), lhigh-spin Fe[HB(3-MePZ)(3)](2), high-spin Fe[HB(3,5-Me(2)PZ)(3)](2), and high-spin Fe ... [more ▼]

Density functional theory has been used to study the electronic spin-state properties of low-spin Fe[HB(PZ)(3)](2), lhigh-spin Fe[HB(3-MePZ)(3)](2), high-spin Fe[HB(3,5-Me(2)PZ)(3)](2), and high-spin Fe[HB(3,4,5-Me(3)PZ)(3)](2) complexes that exhibit very different iron(II) electronic spin-sate crossover behaviors with changing temperature and pressure. Excellent agreement is obtained between the experimentally,observed Mossbauer-effect quadrupole splittings and isomer shifts of these complexes and those calculated with the B3LYP functional and various different basis sets for both the high-spin and low-spin states of iron(II). The calculations for Fe[HB(PZ)(3)](2) that use the LANL2DZ, 6-31++G(d,p), and 6-311++G(d,p) basis sets for iron all lead to very similar electric field gradients and thus quadrupole splittings. The initial calculations, which were based upon the known X-ray structures, were followed by structural optimization, an optimization that led to small increases in the Fe-N bond distances. Optimization led to at most trivial changes in the intraligand bond distances and angles. The importance of the 3-methy I-H center dot center dot center dot H-3-methyl nonbonded intramolecular interligand interactions in controlling the minimum Fe-N bond distances and determining the iron(II) spin state both in Fe[HB(3-Mepz)(3)](2) and in the related methyl-substituted complexes has been identified. [less ▲]

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See detailDensity of herbaceous plants and distribution of western gorillas in different habitat types in south-east Cameroon
Willie, Jacob; Petre, Charles-Albert ULg; Tagg, Nikki et al

in African Journal of Ecology (2013), 51

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See detailDensity of states for a specified correlation function and the energy landscape
Gommes, Cédric ULg; Jiao, Yang; Torquato, Salvatore

in Physical Review Letters (2012)

The degeneracy of two-phase disordered microstructures consistent with a specified correlation function is analyzed by mapping it to a ground-state degeneracy. We determine for the first time the ... [more ▼]

The degeneracy of two-phase disordered microstructures consistent with a specified correlation function is analyzed by mapping it to a ground-state degeneracy. We determine for the first time the associated density of states via a Monte Carlo algorithm. Our results are described in terms of the roughness of the energy landscape, defined on a hypercubic configuration space. The use of a Hamming distance in this space enables us to define a roughness metric, which is calculated from the correlation function alone and related quantitatively to the structural degeneracy. This relation is validated for a wide variety of disordered systems. [less ▲]

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See detailDensity of states of chaotic Andreev billiards
Kuipers, Jack; Engl, Thomas; Berkolaiko, Gregory et al

in PHYSICAL REVIEW B (2011), 83(19), 195316-21

Quantum cavities or dots have markedly different properties depending on whether their classical counterparts are chaotic or not. Connecting a superconductor to such a cavity leads to notable proximity ... [more ▼]

Quantum cavities or dots have markedly different properties depending on whether their classical counterparts are chaotic or not. Connecting a superconductor to such a cavity leads to notable proximity effects, particularly the appearance, predicted by random matrix theory, of a hard gap in the excitation spectrum of quantum chaotic systems. Andreev billiards are interesting examples of such structures built with superconductors connected to a ballistic normal metal billiard since each time an electron hits the superconducting part it is retroreflected as a hole (and vice versa). Using a semiclassical framework for systems with chaotic dynamics, we show how this reflection, along with the interference due to subtle correlations between the classical paths of electrons and holes inside the system, is ultimately responsible for the gap formation. The treatment can be extended to include the effects of a symmetry-breaking magnetic field in the normal part of the billiard or an Andreev billiard connected to two phase-shifted superconductors. Therefore, we are able to see how these effects can remold and eventually suppress the gap. Furthermore, the semiclassical framework is able to cover the effect of a finite Ehrenfest time, which also causes the gap to shrink. However, for intermediate values this leads to the appearance of a second hard gap-a clear signature of the Ehrenfest time. [less ▲]

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See detailDensity-Dependent Reproductive Success In Tribolium Castaneum (Herbst) (Coleoptera : Tenebrionidae)
Assie, L. K.; Brostaux, Yves ULg; Haubruge, Eric ULg

in Journal of Stored Products Research (2008), 44(3), 285-289

Two strains of Tribolium castaneum, one being susceptible to malathion (Asm) and the other malathion-specific resistant (PRm), were used to assess the effect of population density and its interaction with ... [more ▼]

Two strains of Tribolium castaneum, one being susceptible to malathion (Asm) and the other malathion-specific resistant (PRm), were used to assess the effect of population density and its interaction with genetic background in reproductive success. A highly significant allometric relationship between female body weight and fecundity (R2=0.413) and another between female body weight and larval survivorship (R2=0.561) were found. Data showed that population density exerted an indirect effect on the reproductive success. The body weight of the Asm female was not affected by variations in population density but the body weight of the PRm female increased with reduced population density. The genetic background (strain) and/or malathion-specific resistance greatly influenced reproductive success. Concerning the percentage survivorship of offspring of the two strains, there was an opposite trend with increased population density: in PRm, survivorship was lower at high density (76.64±13.75; mean±SD) and higher at low density (88.39±7.61), whereas in Asm, survivorship was higher at high density (53.39±15.57) and lower at low density (43.99±20.08). The PRm female laid more eggs than the Asm. Reproductive success was significantly higher in PRm than in Asm. In addition, the genetic background (the strain) and/or the pleiotropic effect of malathion-specific resistance had a significant effect on the fecundity of PRm because the differences in fecundity and reproductive success between Asm and PRm went beyond the body weight of the female and might be explained by their genetic background and/or the pleiotropic effect of malathion-specific resistance. [less ▲]

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See detailDensity-functional theory of polar insulators
Gonze, X.; Ghosez, Philippe ULg; Godby, R. W.

in Physical Review Letters (1997), 78(2), 294-297

We examine the density-functional theory of macroscopic insulators, obtained in the large-cluster limit or under periodic boundary conditions. For polar crystals, we find that the two procedures are not ... [more ▼]

We examine the density-functional theory of macroscopic insulators, obtained in the large-cluster limit or under periodic boundary conditions. For polar crystals, we find that the two procedures are not equivalent. In a large-cluster case, the exact exchange-correlation potential acquires a homogeneous ''electric field'' which is absent from the usual local approximations, and the Kohn-Sham electronic system becomes metallic. With periodic boundary conditions, such a field ist forbidden, and the polarization deduced from Kohn-Sham wave functions is incorrect even if the exact functional is used. [less ▲]

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See detailDensity-functional theory of the pressure distribution at metal surfaces
Heinrichs, J.; Magain, Pierre ULg

in Physica Status Solidi B. Basic Research (1982), 110

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See detailDENSITY-POLARIZATION FUNCTIONAL THEORY OF THE RESPONSE OF A PERIODIC INSULATING SOLID TO AN ELECTRIC-FIELD
GONZE, X.; Ghosez, Philippe ULg; GODBY, R. W.

in Physical Review Letters (1995), 74(20), 4035-4038

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