Selecting the location of minihubs for freight delivery in congested downtown areas

The delivery of freight in urban areas has to face many restrictions and regulations that constrain the efficient flow of goods. One of the most common regulations in medium and large cities is the establishment of access time windows, whereby delivery vehicles can only access the most central and congested areas of the city during a pre-specified period of the day. To avoid the costs imposed on carriers by this regulation while maintaining the social and environmental sustainability benefits, we propose here the establishment of a system of mini-hubs where delivery vehicles may park for the final deliveries to be completed on foot. Given that the optimal location of these mini-hubs is essential for the operation of the system, we formulate a location model and apply a computational process based on genetic algorithms to optimize it. We apply this procedure to a case study in the Spanish city of Seville, showing the effect of mini-hubs on the costs of the overall delivery system.     

A synthon for a 14-electron Ir(iii) species: catalyst for highly selective β-(Z) hydrosilylation of terminal alkynes

A synthon for a 14-electron Ir(iii) species is described. The geometrical control exerted by the ligand system over the Ir-alkenyl intermediate in hydrosilylation of terminal alkynes precludes formation of the more thermodynamically stable β-(E)-vinylsilane, thus affording the β-(Z) isomer in excellent yields.     

A stable luminescent hybrid mesoporous copper complex-silica

Surfactant-assisted co-condensation of an emissive tetranuclear alkynyl-phosphine copper cluster with TEOS affords a hydrothermally stable blue-emitter mesoporous hybrid metal complex-silica material.     

Microwave-assisted solvent-free synthesis and in vitro antibacterial screening of quinoxalines and pyrido[2, 3b]pyrazines

We report herein the microwave assisted synthesis, without solvents and catalysts, of 6-substituted quinoxalines and 7-substituted pyrido[2,3b]pyrazines. The compounds were obtained in good yields and short reaction times using the mentioned procedure and two new structures are reported. A complete 1H- and 13C-NMR assignment was performed using 1D and 2D-NMR. Additionally, an in vitro screening was performed on Gram-positive and Gram-negative bacteria using amoxicillin as positive reference. Compounds bearing a pyridyl group tended to have higher antibacterial activity, but the best activity against Bacillus subtilis and Proteus mirabilis was observed with quinoxaline derivatives.     

Gastroprotection of Suaveolol, Isolated from <em>Hyptis suaveolens</em>, against Ethanol-Induced Gastric Lesions in Wistar Rats: Role of Prostaglandins, Nitric Oxide and Sulfhydryls

Hyptis suaveolens is a medicinal plant that is, according to traditional medicine, considered useful in the treatment of gastric ulcers. Although its gastroprotective activity was reported, the active compounds have not been identified. Therefore, the aim of the present study was to identify at least one active compound potentially responsible for the gastroprotective activity of H. suaveolens by using a bioassay guided study with an ethanol-induced gastric ulcer experimental model in rats. The results show that the hexane extract had protective activity (close to 70% when using doses between 10 and 100 mg/kg), and that the compound suaveolol, isolated from this extract, was one of the active gastroprotective agents. This is the first report about the gastroprotective activity of suaveolol. Rats treated with this compound at 3, 10, 30 and 100 mg/kg showed 12.6, 21.3, 39.6 and 70.2% gastroprotection respectively. The effect elicited by suaveolol (at 100 mg/kg) was attenuated by pretreatment with either N^G-nitro-L-arginine methyl ester (70 mg/kg, i.p.), a nitric oxide (NO) synthase inhibitor, indomethacin (10 mg/kg, s.c.), a blocker of prostaglandin synthesis, or N-ethylmaleimide (10 mg/kg, s.c.), a blocker of sulfhydryl groups. This suggests that the gastroprotective mechanism of action of this compound involves NO, prostaglandins and sulfhydryl groups.     

Recovery and concentration of antioxidants from winery wastes

Grape and wine byproducts have been extensively studied for the recovery of phenolic compounds with antioxidant activity and a variety of biological actions. The selective recovery and concentration of the phenolic compounds from the liquid phase separated from further diluted winery wastes has been proposed. Adsorption onto non ionic polymeric resins and further desorption with ethanolic solutions was studied. Several commercial food grade resins were screened with the aim of selecting the most suited for the practical recovery of phenolic compounds with radical scavenging activity. Under the optimized desorption conditions (using Sepabeads SP207 or Diaion HP20 as adsorbents and eluting with 96% ethanol at 50 °C) a powdered yellow-light brown product with 50% phenolic content, expressed as gallic acid equivalents, was obtained. The radical scavenging capacity of one gram of product was equivalent to 2-3 g of Trolox.     

Diastereoselective and enantiospecific synthesis of gamma-substituted alpha,beta-unsaturated nitriles from O-protected allylic cyanohydrins

gamma-Functionalized alpha,beta-unsaturated nitriles are prepared diastereoselectively and enantiospecifically from enantioenriched cyanohydrin-O-phosphates and carbonates derived from alpha,beta-unsaturated aldehydes, either by palladium or iridium-catalyzed nucleophilic allylic substitution reactions with different nucleophiles. Appropriate reaction conditions for dibenzylamine, benzylamine, sodium azide, NaOAc, tetra-n-butylammonium acetate (TBAA), the corresponding sodium salts of phenol and N-hydroxysuccinimide and the carbonucleophile sodium dimethyl malonate are described. Different substituted O-protected cyanohydrins, such as carbonates and phosphates, derived from crotonaldehyde, (E)-hex-2-enal, oct-2-enal, 2-methylbut-2-enal, and cinnamaldehyde are used as allylic substrates. The substitution takes place with total retention of the configuration for the (E)-gamma-functionalized nitriles and with inversion of the configuration for the Z-isomers. In general, cyanohydrin-O-phosphates are the materials of choice to get the highest E-diastereoselectivity. Dibenzylamine is the best nucleophile for the synthesis of gamma-nitrogenated alpha,beta-unsaturated nitriles in the presence of either palladium or iridium catalysts when aliphatic compounds and cinnamaldehyde derivative are used (up to 98% dr). For the synthesis of gamma-oxygenated alpha,beta-unsaturated nitriles sodium or TBAA the reagents are selected to avoid epimerizations in up to 76% dr. Finally, the Tsuji-Trost reaction with sodium malonate works only under palladium catalysis in up to 70% dr.