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See detailThe microtubule-associated protein doublecortin is broadly expressed in the telencephalon of adult canaries
Boseret, Géraldine ULg; Ball, G. F.; Balthazart, Jacques ULg

in Journal of Chemical Neuroanatomy (2007), 33(3), 140-154

The protein doublecortin (DCX) is expressed in post-mitotic migrating and differentiating neurons in the developing vertebrate brain and, as a part of the microtubule machinery, is required for neuronal ... [more ▼]

The protein doublecortin (DCX) is expressed in post-mitotic migrating and differentiating neurons in the developing vertebrate brain and, as a part of the microtubule machinery, is required for neuronal migration. DCX expression is generally maximal during embryonic and early post-natal life but decreases markedly and almost disappears in older animals in parallel with the major decrease or cessation of neurogenesis. In several seasonally breeding songbird species such as canaries, the volume of several song control nuclei in the brain varies seasonally such that the largest nuclei are observed in the late spring and early summer. This variation is based on changes in cell size, dendritic branching, and, in nucleus HVC, on the incorporation of neurons newly born in adulthood. Because songbirds maintain an active neurogenesis and neuronal incorporation in their telencephalon throughout their lives, we investigated here the distribution of DCX-immunoreactive (ir) structures in the brain of adult male canaries. Densely stained DCX-ir cells were found exclusively in parts of the telencephalon that are known to incorporate new neurons in adulthood, in particular the nidopallium. Within this brain region, the boundaries of the song control nucleus HVC could be clearly distinguished from surrounding structures by a higher density of DCX-ir structures. In most telencephalic areas, about two thirds of these cells displayed a uni- or bipolar fusiform morphology suggesting they were migrating neurons. The rest of the DCX-ir cells in the telencephalon were larger and had a round multipolar morphology. No such staining was found in the rest of the brain. The broad expression of DCX specifically in adult brain structures that exhibit the characteristic of active incorporation of new neurons suggests that DCX plays a key role in the migration of new neurons in the brain of adult songbirds as it presumably does during ontogeny. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailMicrowave Corneosurfametry and the Short-Duration Dansyl Chloride Extraction Test for Rating Concentrated Irritant Surfactants
Goffin, Véronique ULg; Pierard, Gérald ULg

in Dermatology : International Journal for Clinical & Investigative Dermatology (2001), 202(1), 46-8

BACKGROUND: There are ethical concerns to conduct in vivo tests in the animal and human to provide evidence that cosmetics and other topical products are safe. OBJECTIVE: To compare two methods, namely ... [more ▼]

BACKGROUND: There are ethical concerns to conduct in vivo tests in the animal and human to provide evidence that cosmetics and other topical products are safe. OBJECTIVE: To compare two methods, namely the short-duration dansyl chloride extraction test and the microwave corneosurfametry bioassay, to test the irritation potential of concentrated surfactant systems. METHODS: Five surfactants and water were tested using the in vivo test and the bioassay. RESULTS: A significant linear correlation was found between data yielded by the two procedures. CONCLUSION: The short-duration dansyl chloride extraction test and the microwave corneosurfametry bioassay provide similar information. The latter has the advantage of being safe. [less ▲]

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See detailMicrowave data and a regional climate model for studying the Greenland ice sheet surface mass balance over 1979-2009
Fettweis, Xavier ULg; Marco, Tedesco

Poster (2010, May 03)

Results (melt extent and winter accumulation) from an atmosphere-snow coupled regional climate model are compared with microwave brightness temperatures-derived estimates to study the surface mass balance ... [more ▼]

Results (melt extent and winter accumulation) from an atmosphere-snow coupled regional climate model are compared with microwave brightness temperatures-derived estimates to study the surface mass balance (SMB) changes over the Greenland ice sheet (GrIS) since 1979. Two simple algorithms are selected to retrieve the melt extent from the brightness temperatures. The first one is sensible to the production of surface meltwater as suggests the regional model and the second one is rather sensible to the presence of liquid water content into the snowpack. Both algorithms compare very well with model outputs and they are unanimous to show a significant increase of the surface melt over 1979-2009.We found also a good correlation between the March-April mean brightness temperatures and the simulated winter snow accumulation although no significant changes are found in both simulated and microwave-derived snow accumulation. The interannual variability of the brightness temperature-derived SMB components compare very well with the model results. This suggests that the variability of the model is reliable and that the model can be used to detect SMB changes over longer periods where no satellite data is available. Finally, both model and satellite agree to confirm the acceleration of the GrIS surface melting since 30 years. [less ▲]

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See detailMicrowave drying as an effective method to obtain porous carbon xerogels
Zubizarreta, Leire; Arenillas, Ana; Menendez, J. A. et al

in Journal of Non-Crystalline Solids (2008), 354(33), 4024-4026

Microwave drying was used to prepare resorcinol-formaldehyde aqueous gels, without performing any pretreatment, and to see whether it was possible to use this drying option to obtain porous carbon ... [more ▼]

Microwave drying was used to prepare resorcinol-formaldehyde aqueous gels, without performing any pretreatment, and to see whether it was possible to use this drying option to obtain porous carbon xerogels with controlled textural properties. By using microwave drying, the process for obtaining carbon gels is greatly simplified, textural properties are controlled likewise with other drying methods, but the time involved in the process is significantly reduced and no pretreatment is necessary. Therefore, microwave drying could help to simplify the carbon xerogels synthesis and reduce the associated costs. (C) 2008 Elsevier B.V. All rights reserved. [less ▲]

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See detailMicrowave improved synthesis of p-[18F]MPPF, 5-HT1A antagonist and PET sudies on cat brain.
Le Bars, D.; Ginovart, N.; Lemaire, Christian ULg et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1997), 40

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See detailMicrowave properties of DyBCO monodomain in the mixed state and comparison with other RE-BCO systems
Pompeo, N.; Rogai, R.; Ausloos, Marcel ULg et al

in Physica C: Superconductivity and its Applications (2011), 471(21-22), 854-858

We report on microwave measurements on DyBa 2Cu 3O 7-δ monodomains grown by the top-seeded melt-textured technique. We measured the field increase of the surface resistance R s(H) in the a-b plane at 48.3 ... [more ▼]

We report on microwave measurements on DyBa 2Cu 3O 7-δ monodomains grown by the top-seeded melt-textured technique. We measured the field increase of the surface resistance R s(H) in the a-b plane at 48.3 GHz. Measurements were performed at fixed temperatures in the range 70 K-T c with a static magnetic field μ 0H < 0.8 T parallel to the c-axis. Low field steep increase of the dissipation, typical signature of the presence of weak links, is absent, thus indicating the single-domain behavior of the sample under study. The magnetic field dependence of R s(H) is ascribed to the dissipation caused by vortex motion. The analysis of X s(H) points to a free-flow regime, thus allowing to obtain the vortex viscosity as a function of temperature. We compare the results with those obtained on RE-BCO systems. In particular, we consider strongly pinned films of YBa 2Cu 3O 7-δ with nanometric BaZrO 3 inclusions. © 2011 Elsevier B.V. All rights reserved. [less ▲]

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See detailMicrowave – assisted synthesis of carbohydrate compounds, focus on uronic acid derivatives.
Laurent, Pascal ULg; Richel, Aurore ULg; Wathelet, Bernard ULg et al

Poster (2010, May)

At the moment, biorefining is increasingly seen as a promising alternative to petrochemical sector since it targets both the replacement of part of petroleum as a source of energy and the development of ... [more ▼]

At the moment, biorefining is increasingly seen as a promising alternative to petrochemical sector since it targets both the replacement of part of petroleum as a source of energy and the development of chemicals from the biomass, such as detergents, phytopharmaceutics, solvents, plastics, etc. The valorisation of carbohydrates arising from the hydrolysis of renewable feedstocks is therefore an area of outmost interest. In this context, uronic acids such as glucuronic acid (GlcA) or galacturonic acid (GalA) derived from widely available raw material such as hemicellulose or pectins represent important biocompatible and bioresorbable starting material. The quest of highly effective, environmentally friendly and straightforward chemical strategies to transform totally O-unprotected uronic acids into high valuable materials remains actually a particularly challenging task. A new strategy enabling the quantitative “one-pot” production of water-soluble monosubstituted D-glucofuranosidurono-6,3-lactones from unprotected D-glucuronic acid (D-GlcA) involving microwaves and an inexpensive siliceous-based promoter will be described. The use of a heterogeneous acid catalytic systems consisting of sulfuric acid impregnated onto silica (H2SO4/SiG60) or onto carbon (H2SO4/C), offers a green alternative to unrecyclable liquid sulfuric acid and permit the developpment of a truly eco-friendly green process, as these supported acids were readily separated from liquid products, without neutralization, by decantation or filtration, thus minimizing energy consumption and wastes. Faced with environmental concerns, this solventless methodology offers attractive features, including short reaction times, high yields and easy set-up and workup. [less ▲]

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See detailMicrowave-assisted conversion of carbohydrates. State of the art and outlook.
Richel, Aurore ULg; Laurent, Pascal ULg; Wathelet, Bernard ULg et al

in Comptes Rendus Chimie (2011), 14

The valorisation of carbohydrates arising from the hydrolysis of renewable feedstocks (i.e. lignocellulosic biomass) is nowadays an area of outmost interest. In this context, the implementation of fast ... [more ▼]

The valorisation of carbohydrates arising from the hydrolysis of renewable feedstocks (i.e. lignocellulosic biomass) is nowadays an area of outmost interest. In this context, the implementation of fast, expeditious and cost-effective methodologies for the modification of these naturally occurring compounds is becoming a prerequisite. In this sense, the application of microwaves has gained progressive attention in laboratories for making a range of high-added value sugars derivatives scaffolds. Advantages of microwaves are numerous and include enhancement of reaction rates and yields, combined to improved regio-, chemo- and anomeric selectivities. Summary: 1. Introduction 2. Chemical transformations of monosaccharides Regioselective hydroxyls protections/deprotections Derivatisation at the anomeric position Other derivatisations Microwave-assisted click chemistry Synergy between microwaves and heterogeneous catalysis Enzymatic modifications of monosaccharides 3. Effect of microwave heating on polysaccharides Hydrolysis and pretreatment of cellulose Derivatisation of cellulose 4. Scale-up of microwave-promoted reactions 5. Conclusions [less ▲]

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See detailMicrowave-assisted conversion of carbohydrates. State of the art and outlook.
Richel, Aurore ULg; Laurent, Pascal ULg; Wathelet, Bernard ULg et al

Conference (2010, May)

The valorisation of carbohydrates arising from the hydrolysis of renewable feedstocks (i.e. lignocellulosic biomass) is nowadays an area of outmost interest. In this context, the implementation of fast ... [more ▼]

The valorisation of carbohydrates arising from the hydrolysis of renewable feedstocks (i.e. lignocellulosic biomass) is nowadays an area of outmost interest. In this context, the implementation of fast, expeditous and cost-effective methodologies for the modification of these naturally occurring compounds is becoming a prerequisite. In this sense, the application of microwaves has gained progressive attention in laboratories for making a range of high-added value sugars derivatives scaffolds. Its advantages are numerous and include enhacement of reaction rates and yields combined to improved regio-, chemo- and anomeric selectivities. Since the first publications of Gedye et Giguere in 1986, the use of microwave has progressively emerged as a popular non conventional heating source in the field of organic synthesis.1 Nevertheless, its application in the area of carbohydrate chemistry is less documented.2, 3 Although research in this field is still in its infancy, recourse to microwaves often provides, with remarkable yields and atom efficiency, new carbohydrate-based structures that are not easily available by any another means (or only via painstaking multi-step protocols). This communication proposes therefore selected, recent and non exhaustive illustrations of the application of microwaves to promote famous carbohydrates “model” reactions. The scale-up of such microwave-assisted reactions is also presented. [less ▲]

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See detailMicrowave-Assisted Olefin Metathesis
Nicks, François; Borguet, Yannick ULg; Sauvage, Xavier et al

in Dragutan, Valerian; Demonceau, Albert; Dragutan, Ileana (Eds.) et al Green Metathesis Chemistry (2010)

Since the first reports on the use of microwave irradiation to accelerate organic chemical transformations, a plethora of papers have been published in this field. In most examples, microwave heating has ... [more ▼]

Since the first reports on the use of microwave irradiation to accelerate organic chemical transformations, a plethora of papers have been published in this field. In most examples, microwave heating has been shown to dramatically reduce reaction times, increase product yields, and enhance product purity by reducing unwanted side reactions compared to conventional heating methods. The present contribution aims at illustrating the advantages of this technology in olefin metathesis and, when data are available, at comparing microwave-heated and conventionally heated experiments. [less ▲]

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See detailMicrowave-assisted ruthenium-catalysed atom transfer radical reactions
Delfosse, Sébastien; Richel, Aurore ULg; Wei, H. et al

Conference (2005)

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See detailMicrowave-assisted ruthenium-catalysed atom transfer radical reactions
Delfosse, Sébastien; Richel, Aurore ULg; Wei, H. et al

Poster (2005, August)

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See detailMicrowave-Assisted Ruthenium-Catalyzed Reactions
Nicks, Francois ULg; Borguet, Yannick ULg; Delfosse, Sebastien et al

in Australian Journal of Chemistry (2009), 62(3), 184-207

Since the first reports on the use of microwave irradiation to accelerate organic chemical transformations, a plethora of papers has been published in this field. In most examples, microwave heating has ... [more ▼]

Since the first reports on the use of microwave irradiation to accelerate organic chemical transformations, a plethora of papers has been published in this field. In most examples, microwave heating has been shown to dramatically reduce reaction times, increase product yields, and enhance product purity by reducing unwanted side reactions compared with conventional heating methods. The present contribution aims at illustrating the advantages of this technology in homogeneous catalysis by ruthenium complexes and, when data are available, at comparing microwave-heated and conventionally heated experiments. Selected examples refer to olefin metathesis, isomerization reactions, 1,3-dipolar cycloadditions, atom transfer radical reactions, transfer hydrogenation reactions, and H/D exchange reactions. [less ▲]

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See detailMicrowave-Assisted Synthesis of 1,3-Dimesitylimidazolinium Chloride
Hans, Morgan ULg; Delaude, Lionel ULg

in Wipf, Peter (Ed.) Organic Syntheses. Volume 87 (2010)

A procedure for the microwave-assisted synthesis of 1,3-dimesitylimidazolinium chloride on a preparative scale is described starting from simple, commercially available reagents. Prior to a microwave ... [more ▼]

A procedure for the microwave-assisted synthesis of 1,3-dimesitylimidazolinium chloride on a preparative scale is described starting from simple, commercially available reagents. Prior to a microwave-assisted cyclization, it involves the formation of N,N'-dimesitylethane-1,2-diamine dihydrochloride via condensation of glyoxal with two equivalents of mesitylamine, followed by reduction of the intermediate Schiff base with sodium borohydride under acidic conditions. All three steps proceed readily under normal atmosphere. Laboratory grade solvents and reagents taken straight from the bottles do not require any additional purification. The two intermediates and the final product are isolated in high yield and purity by simple filtration and washing and may be used without any further purification for most applications. [less ▲]

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See detailMicrowave-assisted synthesis of D-glucuronic acid derivatives using cost-effective solid acid catalysts
Richel, Aurore ULg; Laurent, Pascal ULg; Wathelet, Bernard ULg et al

in Tetrahedron Letters (2010), 51

Monomode microwave-assisted coupling of D-glucuronic acid with alcohols, in the presence of various impregnated acid catalysts, was successfully performed, affording in almost quantitative yields the ... [more ▼]

Monomode microwave-assisted coupling of D-glucuronic acid with alcohols, in the presence of various impregnated acid catalysts, was successfully performed, affording in almost quantitative yields the corresponding monosubstituted b-D-glucofuranosidurono-6,3-lactones in less than 10 min at 85°C. This study evidences the synergy of microwaves and impregnated acid catalysts as a fast and clean strategy in the field of carbohydrate chemistry. [less ▲]

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See detailMicrowave-assisted synthesis of imidazolinium salts
Hans, Morgan; Demonceau, Albert ULg; Delaude, Lionel ULg

in Polymer Preprints (2008), 49(2), 942-943

Imidazolinium salts were prepd. via microwave-assisted cyclocondensation of ethanediamines with triethoxy alkanes or triethoxymethyl benzene. The synthesized imidazolinium salts may be used as NHC ... [more ▼]

Imidazolinium salts were prepd. via microwave-assisted cyclocondensation of ethanediamines with triethoxy alkanes or triethoxymethyl benzene. The synthesized imidazolinium salts may be used as NHC precursors or ionic liqs. [less ▲]

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See detailMicrowave-assisted synthesis of N-heterocyclic carbene precursors
Aidouni, Adila; Demonceau, Albert ULg; Delaude, Lionel ULg

in Synlett (2006), (3), 493-495

A very simple and efficient procedure is reported for the synthesis of 1,3-diarylimidazolinium chlorides by cyclization of N,N'-diarylethylenediamines dihydrochlorides with triethyl ortho-formate under ... [more ▼]

A very simple and efficient procedure is reported for the synthesis of 1,3-diarylimidazolinium chlorides by cyclization of N,N'-diarylethylenediamines dihydrochlorides with triethyl ortho-formate under microwave irradiation. [less ▲]

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See detailMicrowave-assisted synthesis of vinyl esters through ruthenium-catalyzed addition of carboxylic acids to alkynes
Nicks, Francois ULg; Libert, Lionel ULg; Delaude, Lionel ULg et al

in Polymer Preprints (2008), 49(2), 944-945

1-Hexen-2-yl 4-acetoxybenzoate was regioselectively prepd. via microwave-assisted ruthenium-catalyzed addn. of 4-acetoxybenzoic acid to 1-hexyne. Species of catalysts, reaction time and temp. play roles ... [more ▼]

1-Hexen-2-yl 4-acetoxybenzoate was regioselectively prepd. via microwave-assisted ruthenium-catalyzed addn. of 4-acetoxybenzoic acid to 1-hexyne. Species of catalysts, reaction time and temp. play roles in the reaction respect to yields and selectivity, therefore were examd. Microwave effect was obsd. and preferred to the generation of the Markovnikov-type product compared to traditional heating. [less ▲]

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See detailMicrowave-Assisted Synthesis of Vinyl Esters through Ruthenium-Catalyzed Addition of Carboxylic Acids to Alkynes
Nicks, Francois ULg; Libert, Lionel ULg; Delaude, Lionel ULg et al

in Australian Journal of Chemistry (2009), 62(3), 227-231

A rapid and efficient method is described for the selective synthesis of enol esters via the microwave-accelerated addition of carboxylic acids to terminal alkynes. The method employs the readily ... [more ▼]

A rapid and efficient method is described for the selective synthesis of enol esters via the microwave-accelerated addition of carboxylic acids to terminal alkynes. The method employs the readily available [RuCl2(p-cymene)(PPh3)] complex as catalyst without the need of bases, and reactions are complete in 20 min. [less ▲]

Detailed reference viewed: 50 (23 ULg)