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See detailOlefin cyclopropanation and insertion into O-H bonds mediated by copper(I) and palladium(II) covalently anchored to silica xerogels
Sacco, Luigi; Lambert, Stéphanie ULg; Pirard, Jean-Paul ULg et al

in Journal of Catalysis (2005), 232(1), 51-59

Copper(I) and palladium(II) ligated to pyrazolylpyridine hearing a tethered (trimethoxysilyl)propyl group in position 4 of the pyrazole ring were chemically bonded to silica via a sol-gel process. The ... [more ▼]

Copper(I) and palladium(II) ligated to pyrazolylpyridine hearing a tethered (trimethoxysilyl)propyl group in position 4 of the pyrazole ring were chemically bonded to silica via a sol-gel process. The textural properties of the materials (Specific Surface area, porous volume, and pore size distribution) were characterized by nitrogen adsorption-desorption isotherms, mercury porosimetry, and TEM analysis. The hybrid materials were tested as catalysts in olefin cyclopropanation and as potential chemoselective catalysts in the reaction with unsaturated alcohols (double bond versus -OH group), with ethyl diazoacetate as a carbene precursor, and compared with the corresponding homogeneous complexes. © 2005 Elsevier Inc. All rights reserved. [less ▲]

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See detailOlefin metathesis as key step in the synthesis of bioactive compounds: Challenges in the total synthesis of (-)-kendomycin
Bicchielli, Dario; Borguet, Yannick ULg; Delaude, Lionel ULg et al

in Current Organic Synthesis (2012), 9(3), 397-405

In this short review article, we highlight the application of the olefin metathesis reaction as a key step in the total synthesis of (-)-kendomycin, a macrocyclic polyketide ansamycin exhibiting ... [more ▼]

In this short review article, we highlight the application of the olefin metathesis reaction as a key step in the total synthesis of (-)-kendomycin, a macrocyclic polyketide ansamycin exhibiting pronounced activity as an endothelin receptor antagonist and antiosteoporotic agent, as well as important antibiotic potency against multiresistant bacteria and remarkable cytotoxicity versus a series of human tumour cell lines. By selecting this example from the recent literature, we hope to illustrate the great synthetic ability of olefin metathesis, while also revealing some problems encountered in the syntheses. © 2012 Bentham Science Publishers. [less ▲]

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See detailOlefin metathesis as key step in the synthesis of bioactive compounds: Challenges in the total synthesis of irioteolides
Demonceau, Albert ULg; Dragutan, I.; Dragutan, V. et al

in Current Organic Synthesis (2012), 9

Iriomoteolides are novel macrolides possessing either a unique 15-membered or a 20-membered macrocycle, and displaying exceedingly potent cytotoxicity with IC50 values of up to 2 ng/mL. Thus far, over a ... [more ▼]

Iriomoteolides are novel macrolides possessing either a unique 15-membered or a 20-membered macrocycle, and displaying exceedingly potent cytotoxicity with IC50 values of up to 2 ng/mL. Thus far, over a period of about four years, ten research groups worldwide have published their synthetic efforts resulting in four total syntheses of iriomoteolides and a few diastereomers thereof, and a number of fragment and macrocyclic core syntheses. Interestingly, three total syntheses involved ring-closing metathesis as the key step for the construction of the macrocycle, whereas the synthesis of three fragments was accomplished using a cross-metathesis reaction. Herein we highlight assets and limitations of the olefin metathesis reaction in the synthesis of the title compounds. [less ▲]

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See detailOlefin metathesis reactions state of the art and outlook
Demonceau, Albert ULg; Delaude, Lionel ULg

in Chimica Oggi = Chemistry Today (2007), 25(5, SEP-OCT), 65-68

Olefin metathesis is a metal-catalysed organic reaction, which involves the statistical redistribution of carbon-carbon double bonds. Since its discovery in the 1950's, this transformation has gained ... [more ▼]

Olefin metathesis is a metal-catalysed organic reaction, which involves the statistical redistribution of carbon-carbon double bonds. Since its discovery in the 1950's, this transformation has gained widespread use in research laboratories and industry for making products ranging, from drugs and polymers to enhanced fuels. Its advantages include the ability to build up complex structural scaffolds with remarkable atom economy. Major industrial processes usually rely on inexpensive, ill-defined, multicomponent catalytic systems, while research laboratory applications take advantage of well-defined metal alkylidene complexes of molybdenum and ruthenium that combine high activities and ease of set-up under reproducible conditions, albeit at the price of a higher cost. [less ▲]

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See detailOlefin metathesis with ruthenium-arene catalysts bearing N-heterocyclic carbene ligands
Delaude, Lionel ULg; Demonceau, Albert ULg

in Dragutan, Valerian; Imamoglu, Yavuz (Eds.) Metathesis Chemistry. From nanostructure design to synthesis of advanced materials (2007)

In this chapter, we summarize the main results of our investigations on the ring-opening metathesis polymn. (ROMP) of cyclooctene catalyzed by various ruthenium (Ru)-arene complexes bearing imidazolin-2 ... [more ▼]

In this chapter, we summarize the main results of our investigations on the ring-opening metathesis polymn. (ROMP) of cyclooctene catalyzed by various ruthenium (Ru)-arene complexes bearing imidazolin-2-ylidene, imidazolidin-2-ylidene, or triazolin-5-ylidene ligands. Three major findings emerged from this study. First, we underscored the intervention of a photochem. activation step due to visible light illumination. Second, we established that the presence of an endocyclic double bond in the carbene ligand central heterocycle was not crucial to achieve high catalytic efficiencies. Third, we demonstrated that ortho-metalation of the N-heterocyclic carbene (NHC) ligand by the Ru center led to inactive catalysts. [less ▲]

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See detailLes oléo-protéagineux dans la CEE : perspectives d'avenir
Burny, Philippe ULg

in Revue de l'Agriculture (1989), 42(2), 741-753

L'agriculture européenne se trouve aujourd'hui dans une phase d'interrogations multiples. Après une période d'expansion extraordinaire, l'heure est à la limitation des productions. Le système des quotas ... [more ▼]

L'agriculture européenne se trouve aujourd'hui dans une phase d'interrogations multiples. Après une période d'expansion extraordinaire, l'heure est à la limitation des productions. Le système des quotas se généralise aux principales productions, sous diverses formes. Contrairement à la situation prévalant il y a quelques années, on dispose, actuellement de trop de terres. Que faut-il en faire ? Une des voies possibles est la culture des oléo-protéagineux, dont la Communauté est fortement déficitaire. Cet article tente de dégager les perspectives d'avenir dans ce secteur important. Pour cela, seront abordés successivement : la situation prévisible, en l'an 2000 et dans un cadre mondial, sur les marchés des huiles et des tourteaux; l'évolution probable dans les divers maillons de la filière (production, transformation, commerce, consommation); la tendance générale de la politique communautaire en ce domaine; les aspects favorables au développement des cultures oléo-protéagineuses dans la Communauté. Si de nombreux éléments entrent en ligne de compte et soulèvent des questions, l'avenir des oléo-protéagineux dépend avant tout de la volonté politique des dirigeants européens et de sa traduction sur le plan financier : ces cultures doivent être rémunératrices pour les producteurs. [less ▲]

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See detailOleuropein or rutin consumption decreases the spontaneous development of OA in Hartley guinea pig
Sanchez, Christelle ULg; Horcajada, Marie-Noëlle; Membrez, Fanny et al

Conference (2013, November 23)

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See detailOleuropein or rutin consumption decreases the spontaneous development of OA in Hartley guinea pig
Sanchez, Christelle ULg; Horcajada, Marie-Noëlle; Membrez, Fanny et al

in Arthritis and Rheumatism (2013), 65

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See detailOlfaction in athletes with concussion
Charland-Verville, Vanessa ULg; Lassonde, Maryse; Frasnelli, Johannes

in American journal of rhinology & allergy (2012), 26(3), 222-226

BACKGROUND: Moderate to severe traumatic brain injuries (TBIs) commonly lead to olfactory dysfunction; it is, however, unclear whether and to what degree mild TBI such as concussions, which are common ... [more ▼]

BACKGROUND: Moderate to severe traumatic brain injuries (TBIs) commonly lead to olfactory dysfunction; it is, however, unclear whether and to what degree mild TBI such as concussions, which are common sports injuries, affect olfactory function. We therefore aimed to evaluate smell function in athletes who sustained one or more sport concussions in a cross-sectional design. METHODS: Twenty-two University-level football players with one or multiple concussions and 13 control athletes without a history of concussion participated. We measured olfactory function by using the Sniffin' Sticks test to assess subjects' ability to discriminate and identify odors as well as their detection thresholds. In addition, we assessed odor intensity and pleasantness. RESULTS: We used number of concussions and time since the last concussion as independent variables and measure of olfactory function as dependent variables. Although we did not observe any significant effect of the number of concussions, athletes with a longer delay from time of concussion scored significantly weaker than more recently concussed subjects on the odor identification test and on an aggregate olfactory score. Accordingly, we observed a significant negative linear correlation between the odor identification score and the time elapsed since the last concussion. CONCLUSION: These findings suggest a possible degenerative effect of concussions on olfactory function. [less ▲]

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See detailOlfactory ensheathing cells, olfactory nerve fibroblasts and biomatrices to promote long-distance axon regrowth and functional recovery in the dorsally hemisected adult rat spinal cord
Deumens, R.; Koopmans, G. C.; Honig, W. M. M. et al

in Experimental Neurology (2006), 200(1), 89-103

Cellular transplantation, including olfactory ensheathing cells (OEC) and olfactory nerve fibroblasts (ONF), after experimental spinal cord injury in the rat has previously resulted in regrowth of severed ... [more ▼]

Cellular transplantation, including olfactory ensheathing cells (OEC) and olfactory nerve fibroblasts (ONF), after experimental spinal cord injury in the rat has previously resulted in regrowth of severed corticospinal (CS) axons across small lesion gaps and partial functional recovery. In order to stimulate CS axon regrowth across large lesion gaps, we used a multifactorial transplantation strategy to create an OEC/ONF continuum in spinal cords with a 2-mm-long dorsal hemisection lesion gap. This strategy involved the use of aligned OEG/ONF-poly(D,L)-lactide biomatrix bridges within the lesion gap and OEC/ONF injections at I mm rostral and caudal to the lesion gap. In order to test the effects of this complete strategy, control animals only received injections with culture medium rostral and caudal to the lesion gap. Anatomically, our multifactorial intervention resulted in an enhanced presence of injured CS axons directly rostral to the lesion gap (65.0 +/- 12.8% in transplanted animals versus 13.1 +/- 3.9% in control animals). No regrowth of these axons was observed through the lesion site, which may be related to a lack of OEC/ONF survival on the biomatrices. Furthermore, a 10-fold increase of neurofilament-positive axon ingrowth into the lesion site as compared to untreated control animals was observed. With the use of quantitative gait analysis, a modest recovery in stride length and swing speed of the hind limbs was observed. Although multifactorial strategies may be needed to stimulate repair of large spinal lesion gaps, we conclude that the combined use of OEC/ONF and poly(D,L)-lactide biomatrices is rather limited. [less ▲]

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See detailOlfactory Receptors
Parmentier, M.; Schurmans, Stéphane ULg; Libert, F. et al

in Peroutka, S. (Ed.) Handbook of Receptors and Channels: G Protein Coupled Receptors (1994)

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See detailOlfactory receptors are displayed on dog mature sperm cells
Vanderhaeghen, P.; Schurmans, Stéphane ULg; Vassart, G. et al

in Journal of Cell Biology (1993), 123

Olfactory receptors constitute a huge family of structurally related G protein-coupled receptors, with up to a thousand members expected. We have shown previously that genes belonging to this family were ... [more ▼]

Olfactory receptors constitute a huge family of structurally related G protein-coupled receptors, with up to a thousand members expected. We have shown previously that genes belonging to this family were expressed in the male germ line from both dog and human. The functional significance of this unexpected site of expression was further investigated in the present study. We demonstrate that a few dog genes representative of various subfamilies of olfactory receptors are expressed essentially in testis, with little or no expression in olfactory mucosa. Other randomly selected members of the family show the expected site of expression, restricted to the olfactory system. Antibodies were generated against the deduced amino acid sequence of the most abundantly expressed olfactory receptor gene in dog testis. The purified serum was able to detect the gene product (DTMT receptor) in late round and elongated spermatids, as well as in the cytoplasmic droplet that characterizes the maturation of dog sperm cells, and on the tail midpiece of mature spermatozoa. Western blotting further confirmed the presence of a 40-kD immunoreactive protein in the membrane of mature sperm cells. Altogether , these results demonstrate that the main expression site of a subset of the large olfactory receptor gene family is not olfactory mucosa but testis. This expression correlates with the presence of the corresponding protein during sperm cell maturation, and on mature sperm cells. The pattern of expression is consistent with a role as sensor for unidentified chemicals possibly involved in the control of mammalian sperm maturation, migration, and/or fertilization [less ▲]

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See detailOlfactory responses to aphid and host plant volatile releases: (E)-beta-farnesene an effective kairomone for the predator Adalia bipunctata.
Francis, Frédéric ULg; Lognay, Georges ULg; Haubruge, Eric ULg

in Journal of Chemical Ecology (2004), 30(4), 741-55

The volatiles released from several aphid and host plant species, alone or associated, were studied for their infochemical role in prey location. Using a four-arm olfactometer, the attraction of several ... [more ▼]

The volatiles released from several aphid and host plant species, alone or associated, were studied for their infochemical role in prey location. Using a four-arm olfactometer, the attraction of several combinations of three aphid (Myzus persicae, Acyrthosiphon pisum, and Brevicoryne brassicae) and three plant (Vicia faba, Brassica napus, and Sinapis alba) species toward Adalia bipunctata larvae and adults was observed. Both predatory larvae and adults were attracted only by A. pisum and M. persicae when they were crushed, whatever the host plant. (E)-beta-farnesene, the aphid alarm pheromone, was the effective kairomone for the ladybird. Plant leaves alone (V. faba, B. napus, and S. alba) or in association with nonstressed whole aphids (the three species) did not have any attraction for the predator. The B. brassicae specialist aphid is the only prey that was not attracted to A. bipunctata larvae and adults, even if they were crushed. Release of B. brassicae molecules similar to the host plant allelochemicals was demonstrated by GC-MS analysis. The lack of behavioral response of the ladybird at short distance toward the cruciferous specialist aphid was related only to the absence of (E)-beta-farnesene in the aphid prey volatile pattern. [less ▲]

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See detailOlfactory systems in mate recognition and sexual behavior.
Keller, Matthieu; Pillon, Delphine; Bakker, Julie ULg

in Vitamins and Hormones (2010), 83

Olfactory signals play an important role so that breeding efforts are synchronized with appropriate social and environmental circumstances. In this context, the mammalian olfactory system is characterized ... [more ▼]

Olfactory signals play an important role so that breeding efforts are synchronized with appropriate social and environmental circumstances. In this context, the mammalian olfactory system is characterized by the existence of several olfactory subsystems that have evolved to process olfactory information. While the vomeronasal (or accessory) olfactory system is usually conceived as being involved in the processing of pheromonal signals due to its close connections with the reproductive hypothalamus, the main olfactory system is, by contrast, considered as a general analyzer of volatile chemosignals, especially those that are used for the social identification of conspecifics. In fact, several recent sets of experiments suggest that both the main and accessory olfactory systems have the ability to process partly overlapping pheromonal chemosignals and that both systems converge at a downstream level of pheromonal processing. As a consequence, both systems have the ability to support complimentary aspects in mate discrimination and sexual behavior. However, the relative roles played by these systems and their interactions are at present still far from being understood. [less ▲]

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See detailThe OLFR1 gene encoding the HGMP07E putative olfactory receptor maps to the 17p12-17p13 region of the human genome and reveals a MspI restriction fragment lenght polymorphism
Schurmans, Stéphane ULg; Muscatelli, F.; Miot, F. et al

in CytoGenetics & Cell Genetics (1993), 63

Olfactory receptors are believed to be encoded by an extremely large subfamily of G protein-coupled receptors. A human gene (OLFR1) encoding a member of this family was cloned from a genomic library by ... [more ▼]

Olfactory receptors are believed to be encoded by an extremely large subfamily of G protein-coupled receptors. A human gene (OLFR1) encoding a member of this family was cloned from a genomic library by cross-hybridization with a gene fragment obtained by the polymerase chain reaction. The nucleotide sequence of a 3.4-kb EcoRI fragment was determined, and the protein sequence was deduced from the single open reading frame. The gene was assigned by in situ hybridization of metaphase chromosomes to the 17p13-->p12 region of the human genome, in proximity to the tumor-suppressor gene encoding p53. When used as a probe on Southern blots under moderately stringent conditions, it hybridizes to at least three closely related genes. A restriction fragment length polymorphism was detected after MspI digestion. Mendelian segregation of the gene was assessed in three CEPH families, and linkage analysis confirmed the localization of the locus [less ▲]

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See detailOlgierd Kuty. Un parcours sociologique
Vrancken, Didier ULg

in Vrancken, Didier; Dubois, Christophe; Schoenaers, Frédéric (Eds.) Penser la négociation. Mélanges en hommage à Olgierd Kuty (2008)

Cet article retrace les principales étapes du parcours sociologique d'Olgierd Kuty. Depuis ses débuts, à une théorisation générale du droit, de l'organisation et de la société en passant par l'analyse des ... [more ▼]

Cet article retrace les principales étapes du parcours sociologique d'Olgierd Kuty. Depuis ses débuts, à une théorisation générale du droit, de l'organisation et de la société en passant par l'analyse des politiques sociales, les travaux d'Olgierd Kuty se sont déclinés autour d'une thématique transversale, celle de l'analyse de la négociation. [less ▲]

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