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See detailLifting of valid inequalities revisited
Louveaux, Quentin ULg

Conference (2003, August)

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See detailLifting, Superadditivity, Mixed Integer Rounding and Single Node Flow Sets Revisited
Louveaux, Quentin ULg; Wolsey, Laurence A.

in Annals of Operations Research (2007), 153(1), 47-77

In this survey we attempt to give a unified presentation of a variety of results on the lifting of valid inequalities, as well as a standard procedure com- bining mixed integer rounding with lifting for ... [more ▼]

In this survey we attempt to give a unified presentation of a variety of results on the lifting of valid inequalities, as well as a standard procedure com- bining mixed integer rounding with lifting for the development of strong valid inequalities for knapsack and single node flow sets. Our hope is that the latter can be used in practice to generate cutting planes for mixed integer programs. The survey contains essentially two parts. In the first we present lifting in a very general way, emphasizing superadditive lifting which allows one to lift simultane- ously different sets of variables. In the second, our procedure for generating strong valid inequalities consists of reduction to a knapsack set with a single continuous variable, construction of a mixed integer rounding inequality, and superaddilifting. It is applied to several generalizations of the 0-1 single node flow set. [less ▲]

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See detailLifting, Superadditivity, Mixed Integer Rounding and Single Node Flow Sets Revisited
Louveaux, Quentin ULg; Wolsey, Laurence A.

in 4OR : Quarterly Journal of the Belgian, French and Italian Operations Research Societies (2003), 1

In this survey we attempt to give a unified presentation of a variety of results on the lifting of valid inequalities, as well as a standard procedure combining mixed integer rounding with lifting for the ... [more ▼]

In this survey we attempt to give a unified presentation of a variety of results on the lifting of valid inequalities, as well as a standard procedure combining mixed integer rounding with lifting for the development of strong valid inequalities for knapsack and single node flow sets. Our hope is that the latter can be used in practice to generate cutting planes for mixed integer programs. The survey contains essentially two parts. In the first we present lifting in a very general way, empha- sizing superadditive lifting which allows one to lift simultaneously different sets of variables. In the second, our procedure for generating strong valid inequalities consists of reduction to a knapsack set with a single continuous variable, construc- tion of a mixed integer rounding inequality, and superadditive lifting. It is applied to several generalizations of the 0-1 single node flow set. [less ▲]

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See detailA ligament influences the diversification of damselfishes (Pomacentridae)
Frederich, Bruno ULg; Olivier, Damien ULg; Litsios, Glenn et al

Conference (2013, June)

The Pomacentridae (damselfishes) is one of the most successful families of reef-associated fishes (386 species). In 1981, Stiassny described a synapomorphic trait of the Pomacentridae: the cerato ... [more ▼]

The Pomacentridae (damselfishes) is one of the most successful families of reef-associated fishes (386 species). In 1981, Stiassny described a synapomorphic trait of the Pomacentridae: the cerato-mandibular ligament (CML) joining the hyoid bar (ceratohyal) to the internal part of the mandible (coronoid process of the articulo-angular). Here, we highlight that this ligament is lacking in at least 18 damselfish species from different subclades (i.e. Chrominae, Abudefdufinae and Pomacentrinae) and we explore the impact of its disappearance on lineage, morphological and ecological diversification through their evolutionary history. Using a time-calibrated phylogeny including 208 species, we found no support for different rates of lineage diversification between species that lack the CML and the others. Yet, the CML clearly governs a part of the morphological diversity in damselfishes. Indeed, the body and mandible shapes differ significantly between species without CML and the others. Evolutionary modeling of some phenotypic traits (i.e. body and mandible shape) mainly supports models with two rates of morphological diversification across the time-tree with the species without CML having a higher rate of morphological diversification than the others. Mapping the diet of all studied species illustrates that damselfishes lacking CML are highly zooplanktivorous species. Their shapes suggest they feed on planktonic copepods with a higher contribution of ram-feeding (i.e. predator movement towards prey) in comparison with the other planktivorous damselfishes. Finally, the CML could have promoted easy shifts among the three main trophic guilds in damselfishes (i.e. grazers, zooplanktivorous and omnivorous) during evolution but the disappearance of the CML allowed a functional specialization linked to prey-capture strategies. These results support the primary role of the CML in the evolution and diversification of pomacentrids. [less ▲]

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See detailLigamentoplasties du genou : Intérêt d'un renforcement musculaire préopératoire
Croisier, Jean-Louis ULg; Delcour, Jean-Pierre; Crielaard, Jean-Michel ULg

in Actes du 8ème Congrès National de la Société française de Médecine de Rééducation et de Réadaptation (1993, September)

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See detailLigamentoplasties du genou: l'état musculaire préopératoire conditionne t il le degré d'amyotrophie postopératoire?
Croisier, Jean-Louis ULg; Delcour, J. P.; Crielaard, Jean-Michel ULg

in Annales de Réadaptation et de Médecine Physique (1994), 37

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See detailLigand and Solvation Effects on the Electronic Properties of Au-55 Clusters: A Density Functional Theory Study
Periyasamy, Ganga ULg; Remacle, Françoise ULg

in Nano Letters (2009), 9(8), 3007-3011

The electronic properties of the neutral, positively and negatively charged bare Au-55, passivated Au-55(PH3)(12), Au-55(PH3)(12)Cl-6, and solvated Au-55(PH3)(12)Cl-6 54 H2O clusters are studied using ... [more ▼]

The electronic properties of the neutral, positively and negatively charged bare Au-55, passivated Au-55(PH3)(12), Au-55(PH3)(12)Cl-6, and solvated Au-55(PH3)(12)Cl-6 54 H2O clusters are studied using density functional theory. The presence of Cl atoms in the ligand shell favors a nonmetallic behavior while a more metallic behavior is induced by explicit solvation of Au-55(PH3)(12)Cl-6 with water molecules. The trends observed in the electronic properties upon ligation and solvation are in agreement with experimental studies, [less ▲]

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See detailLigand and solvation effects on the structural and electronic properties of small gold clusters
Dufour, F.; Fresch, Barbara ULg; Durupthy, O. et al

in Journal of Physical Chemistry C: Nanomaterials, Interfaces, and Hard Matter (2014), 118(8), 4362

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See detailLigand binding mode to duplex and triplex DNA assessed by combining electrospray tandem mass spectrometry and molecular modeling
Rosu, Frédéric ULg; Nguyen, Chi-Hung; De Pauw, Edwin ULg et al

in Journal of the American Society for Mass Spectrometry (2007), 18(6), 1052-1062

In this paper, we report the analysis of seven benzopyridoindole and benzopyridoquinoxaline drugs binding to different duplex DNA and triple helical DNA, using an approach combining electrospray ... [more ▼]

In this paper, we report the analysis of seven benzopyridoindole and benzopyridoquinoxaline drugs binding to different duplex DNA and triple helical DNA, using an approach combining electrospray ionization mass spectrometry (ESI-MS), tandem mass spectrometry (MS/MS), and molecular modeling. The ligands were ranked according to the collision energy (CE(50)) necessary to dissociate 50% of the complex with the duplex or the triplex in tandem MS. To determine the probable ligand binding site and binding mode, molecular modeling was used to calculate relative ligand binding energies in different binding sites and binding modes. For duplex DNA binding, the ligand-DNA interaction energies are roughly correlated with the experimental CE(50), with the two benzopyridoindole ligands more tightly bound than the benzopyridoquinoxaline ligands. There is, however, no marked AT versus GC base preference in binding, as supported both by the ESI-MS and the calculated ligand binding energies. Product ion spectra of the complexes with triplex DNA show only loss of neutral ligand for the benzopyridoquinoxalines, and loss of the third strand for the benzopyridoindoles, the ligand remaining on the duplex part. This indicates a higher binding energy of the benzopyridoindoles, and also shows that the ligands interact with the triplex via the duplex. The ranking of the ligand interaction energies compared with the CE(50) values obtained by MS/MS on the complexes with the triplex clearly indicates that the ligands intercalate via the minor groove of the Watson-Crick duplex. Regarding triplex versus duplex selectivity, our experiments have demonstrated that the most selective drugs for triplex share the same heteroaromatic core. [less ▲]

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See detailLigand Binding Study of Human PEBP1/RKIP: Interaction with Nucleotides and Raf-1 Peptides Evidenced by NMR and Mass Spectrometry
Tavel, Laurette ULg; Jaquillard, Lucie; Karsisiotis, Andreas et al

in PLoS ONE (2012), 7(4): e36187

Background Human Phosphatidylethanolamine binding protein 1 (hPEBP1) also known as Raf kinase inhibitory protein (RKIP), affects various cellular processes, and is implicated in metastasis formation and ... [more ▼]

Background Human Phosphatidylethanolamine binding protein 1 (hPEBP1) also known as Raf kinase inhibitory protein (RKIP), affects various cellular processes, and is implicated in metastasis formation and Alzheimer's disease. Human PEBP1 has also been shown to inhibit the Raf/MEK/ERK pathway. Numerous reports concern various mammalian PEBP1 binding ligands. However, since PEBP1 proteins from many different species were investigated, drawing general conclusions regarding human PEBP1 binding properties is rather difficult. Moreover, the binding site of Raf-1 on hPEBP1 is still unknown. Methods/Findings In the present study, we investigated human PEBP1 by NMR to determine the binding site of four different ligands: GTP, FMN, and one Raf-1 peptide in tri-phosphorylated and non-phosphorylated forms. The study was carried out by NMR in near physiological conditions, allowing for the identification of the binding site and the determination of the affinity constants KD for different ligands. Native mass spectrometry was used as an alternative method for measuring KD values. Conclusions/Significance Our study demonstrates and/or confirms the binding of hPEBP1 to the four studied ligands. All of them bind to the same region centered on the conserved ligand-binding pocket of hPEBP1. Although the affinities for GTP and FMN decrease as pH, salt concentration and temperature increase from pH 6.5/NaCl 0 mM/20°C to pH 7.5/NaCl 100 mM/30°C, both ligands clearly do bind under conditions similar to what is found in cells regarding pH, salt concentration and temperature. In addition, our work confirms that residues in the vicinity of the pocket rather than those within the pocket seem to be required for interaction with Raf-1. [less ▲]

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See detailLigand binding to tetra-end-linked (TGGGGT)4 G-quadruplexes: an electrospray mass spectroscopy study
Amato, Jussara; Oliviero, Giorgia; Borbone, Nicola et al

in Nucleic Acids Symposium Series (2008), 52

The binding properties of a series of known G-quadruplex ligands have been studied by ESI-MS experiments. The tetramolecular (TG(4)T)(4) quadruplex and its analogues I and II blocked, respectively, at the ... [more ▼]

The binding properties of a series of known G-quadruplex ligands have been studied by ESI-MS experiments. The tetramolecular (TG(4)T)(4) quadruplex and its analogues I and II blocked, respectively, at the 3' or 5'-end by a tetra-end-linker (TEL) unit were chosen as the ligands targets. The stoichiometries of the obtained complexes as well as the ligand affinity and selectivity to the different quadruplexes were determined to deduce the ligand binding site. The TEL derivatives I and II allowed the probing of the grooves contribution to the binding of ligands to G-quadruplexes, demonstrating that the 3' and 5' quartets are not equivalent binding sites for ligand end-stacking. [less ▲]

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See detailLIGAND-INDEPENDENT IDENTIFICATION OF ORPHAN GPCR ARRESTIN BINDING
Dupuis, Nadine ULg; Gilissen, Julie ULg; Derj, Anouar ULg et al

Poster (2014, June 05)

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See detailLigand-independent Identification of orphan GPCR Signaling pathways
Dupuis, Nadine ULg; Gilissen, Julie; Derj, Anouar ULg et al

Conference (2014, July 16)

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See detailLigands and tracers for PET studies of the 5-HT system--current status.
Crouzel, C.; Guillaume, Marcel ULg; Barre, L. et al

in International Journal of Radiation Applications and Instrumentation. Part B : Nuclear Medicine and Biology (1992), 19(8), 857-70

The status of the radiochemical development and biological evaluation of radioligands and tracers for PET studies of the serotonergic system is reviewed, indicating those agents with present value and ... [more ▼]

The status of the radiochemical development and biological evaluation of radioligands and tracers for PET studies of the serotonergic system is reviewed, indicating those agents with present value and those with future potential. Practical recommendations are given for the preparation of two useful radioligands for PET studies of central 5-HT2 receptors, namely [18F]setoperone and [18F]altanserin. Though, it has not proved possible to recommend tracers or radioligands for the study of other aspects of serotonergic system, prospects for future radiochemical development are indicated, especially for developing radioligands for the 5-HT re-uptake site, and for the 5-HT1 and 5-HT3 receptors. [less ▲]

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See detailLigands playing musical chairs with G-quadruplex DNA: A rapid and simple displacement assay for identifying selective G-quadruplex binders
Monchaud, David; Allain, C.; Bertrand, Hélène et al

in Biochimie (2008), 90(8), 1207-1223

We report here the details of G4-FID (G-quadruplex fluorescent intercalator displacement), a simple method aiming at evaluating quadruplex DNA binding affinity and quadruplex- over duplex-DNA selectivity ... [more ▼]

We report here the details of G4-FID (G-quadruplex fluorescent intercalator displacement), a simple method aiming at evaluating quadruplex DNA binding affinity and quadruplex- over duplex-DNA selectivity of putative ligands. This assay is based on the loss of fluorescence upon displacement of thiazole orange from quadruplex and duplex-DNA matrices. The original protocol was tested using various quadruplex and duplex-DNA targets, and with a wide panel of G-quadruplex ligands belonging to different families (i.e. from quinacridines to metalloorganic ligands) likely to display various binding modes. The reliability of the assay is further supported by comparisons with FRET-melting and ESI-MS assays. [less ▲]

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See detailLigated anionic block copolymerization of methyl methacrylate with n-butyl acrylate and n-nonyl acrylate as promoted by lithium 2-(2-methoxyethoxy) ethoxide/diphenylmethyllithium
Nugay, Nihan; Nugay, Turgut; Jérôme, Robert ULg et al

in Journal of Polymer Science. Part A, Polymer Chemistry (1997), 35(8), 1543-1548

Poly(methyl methacrylate-b-n-butyl acrylate) (PMMA-b-Pn-BuA) and poly(methyl methacrylate-b-n-nonyl acrylate) (PMMA-b-Pn-NonA) diblock copolymers have been successfully synthesized by the sequential ... [more ▼]

Poly(methyl methacrylate-b-n-butyl acrylate) (PMMA-b-Pn-BuA) and poly(methyl methacrylate-b-n-nonyl acrylate) (PMMA-b-Pn-NonA) diblock copolymers have been successfully synthesized by the sequential anionic polymerization of methyl methacrylate (MMA) and the n-alkyl acrylate (n-BuA or n-NonA), in a 90/10 toluene/ tetrahydrofuran (THF) mixture at -78°C. When diphenylmethyllithium (DPMLi) ligated with lithium 2-(2-methoxyethoxy) ethoxide (LiOEEM) is used as the initiator, the polymerization of each block appears to be living. Molecular weight and composition of block copolymers can be predicted from the monomer over initator molar ratio and the molecular weight distribution is narrow. Size exclusion chromatography (SEC) supports that no homo-PMMA contaminates the final copolymer. Although the reverse polymerization sequence Pn-NonA-b-PMMA always results in some contamination by homo-Pn-NonA, it has no really significant effect on the final product characteristics. [less ▲]

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