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Nacima Labadie Renata Mansini Jan Melechovský Roberto Wolfler Calvo 《European Journal of Operational Research》2012
The Team Orienteering Problem (TOP) is a known NP-hard problem that typically arises in vehicle routing and production scheduling contexts. In this paper we introduce a new solution method to solve the TOP with hard Time Window constraints (TOPTW). We propose a Variable Neighborhood Search (VNS) procedure based on the idea of exploring, most of the time, granular instead of complete neighborhoods in order to improve the algorithm’s efficiency without loosing effectiveness. The method provides a general way to deal with granularity for those routing problems based on profits and complicated by time constraints. Extensive computational results are reported on standard benchmark instances. Performance of the proposed algorithm is compared to optimal solution values, when available, or to best known solution values obtained by state-of-the-art algorithms. The method comes out to be, on average, quite effective allowing to improve the best know values for 25 test instances. 相似文献
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Sukanta Bhattacharyya Sunil RanaOwen W Gooding Jeff Labadie 《Tetrahedron letters》2003,44(27):4957-4960
A novel polymer-supported triacetoxyborohydride reagent for reductive amination of aldehydes and ketones is reported. The bound reagent was found to be shelf-stable and provided broad scope and reactivity in reductive amination reactions under mild reaction conditions. Streamlined protocols for its application in reductive amination reactions using both primary and secondary amines are described. 相似文献
24.
GuillermoR. Labadie LilianaE. Luna RaquelM. Cravero Manuel Gonzlez‐Sierra 《Helvetica chimica acta》2006,89(11):2732-2737
The partial structure 2 of the bisketal‐type, tetracyclic saudin ( 1 ), an important natural product, was de novo synthesized. A key step was the Jones oxidation of the epoxide 3 , which gave rise to epoxide‐ring opening, followed by acetal hydrolysis, alcohol oxidation, and, finally, intramolecular acetal formation. The resulting key intermediate was finally oxidized to the target lactone 2 . 相似文献
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Rossiter S Woo CK Hartzoulakis B Wishart G Stanyer L Labadie JW Selwood DL 《Journal of combinatorial chemistry》2004,6(3):385-390
A N-derivatized 3-dimethylaminopropyloxypyrazole library was prepared using solution-phase parallel synthesis. The library was designed using physicochemical constraints designed to remove non-membrane-permeable molecules. Cupric acetate-mediated N-arylation with aryl boronic acids proceeded regioselectively to form the N-2-substituted derivatives. The presence of the 3-dimethylaminopropyloxy group was found to completely control the regioselectivity of the arylation. Presence of a dimethylaminoethyloxy or dimethylaminobutyloxy group gave a lesser degree of regioselectivity. The scope of the method as applied to library synthesis is discussed. 相似文献
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Marie-Hélène Dévier Pierre Labadie Anne Togola Hélène Budzinski 《Analytica chimica acta》2010,657(1):28-879
A simple analytical procedure for the simultaneous determination of eight endogenous steroids (testosterone, androstenedione, 17β-estradiol, estrone, pregnenolone, progesterone, dihydroandrostenedione, and dihydrotestosterone) in aquatic molluscs by solid-phase extraction (SPE) and gas chromatography/mass spectrometry (GC-MS) has been developed. After a microwave-assisted extraction, samples were further extracted and purified using two successive SPE (EnviChrom-P and NH2) cartridges. Steroids were derivatized with a mixture of N-methyl-N(trimethylsilyl)trifluoroacetamide (MSTFA)/mercaptoethanol/ammonium iodide (NH4I) and determined by GC-MS in selective ion monitoring mode. Recoveries were in the range 85-114%, although slightly lower for dihydrotestosterone, and the repeatability of the procedure, expressed as the coefficient of variation, was lower than 16%. The limits of detection determined in digestive glands of mussels were in the range 0.1-0.4 ng g−1 wet weight for all the steroids. The developed procedure was then applied to the monitoring of steroid profiles in the digestive glands of mussels from the Arcachon Bay (France) during two reproductive cycles. In parallel, two physiological parameters (lipid content and the condition index of mussels) were also monitored, as well as the seawater temperature and salinity. Only progesterone and pregnenolone were detected in the digestive glands of mussels, and the seasonal variations of progesterone levels seemed to be related to the spawning periods of Mytilus sp. in the Bay. The current challenge for the determination of natural steroids in aquatic invertebrates is also briefly discussed. 相似文献
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Highly efficient, new protocols for the attachment of primary amines to indole aldehyde resin using Ti(OiPr)4-NaBH4 and CH(OMe)3-NaBH3CN-HOAc are reported. Mild cleavage conditions for the release of urea, amide and sulfonamide products from the solid support using 1% trifluoroacetic acid (TFA) are developed. 相似文献
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A series of α-tetralones, with different degree of substitution, was submitted to the Birch reduction-alkylation procedure using various alkylating agents, to produce angularly substituted 1,4-unsaturated decalones. The stereoselectivity behavior of such dienones upon reduction is also described. 相似文献