Now showing items 21-30 of 76
Fisico-química de las aguas superficiales de la Cuenca del río Rincón, Península de Osa, Costa Rica
Hydrochemistry of the surface waters at the Rincon River Basin, Osa Peninsula, Costa Rica
The Rincon River Basin is characterized by steep and rugged topography with outcrops of recent sediments as well as igneous and sedimentary rocks. The area is mostly covered by forest (Tropical Wet Forest) and agricultural ...
Removal of both N-nitrosodimethylamine and trihalomethanes precursors in a single treatment using ion exchange resins
Drinking water utilities are relying more than ever on water sources impacted by wastewater effluents. Disinfection/oxidation of these waters during water treatment may lead to the formation of several disinfection ...
The role of chloramine species in NDMA formation
N-nitrosodimethylamine (NDMA), a probable human carcinogen disinfection by-product, has been detected in chloraminated drinking water systems. Understanding its formation over time is important to control NDMA levels in ...
Microwave assisted synthesis: A Mn/Ni reaction system affording Mn5Ni4, Mn2Ni2 and Mn7 complexes
Following our interest in microwave assisted synthesis in coordination chemistry; we report here the results of the study of a mixed metal Mn/Ni system under common bench-top conditions and using the microwave reactor. ...
Experimental and theoretical studies of C–H⋯M interactions in palladium and platinum complexes derived from 1,2-bis-(2-hydroxymethylphenylthio)ethane
The molecular structures of several related cis-[j2-SS-(L)MHal2] compounds 1, 1DMSO, 2, 2H2O, 3DMSO, 4 and 5 where L = HOCH2Ph-S-CH2-CH2-S-PhCH2OH, M = Pd or Pt, and Hal = Cl or Br or I, were analyzed by single crystal ...
Estrogenic and serotonergic butenolides from the leaves of Piper hispidum Swingle (Piperaceae)
(Journal of Ethnopharmacology 129(2): 220–226, 2010)
Ethnopharmacological relevance: Our previous work has demonstrated that several plants in the Piperaceae family are commonly used by the Q’eqchi Maya of Livingston, Guatemala to treat amenorrhea, dysmenorrhea, and pain. ...
Pheromone chirality of african palm weevil, Rhynchophorus phoenicis (F.) and palmetto weevil, Rhynthophorus crueniatus (F.) (Coleoptera: Curculionidae)
There are four stereoisomers of both 3-methyl-octan-4-ol, the aggregation pheromone of the African palm weevil,Rhynchophorus phoenicis (F.) and 5-methyl-octan-4-ol, the aggregation pheromone of the palmetto weevil,Rhynchophorus ...
Ethyl propionate: Synergistic kairomone for african palm weevil,Rhynchophorus phoenicis L. (Coleoptera: Curculionidae)
Small trunk pieces of a freshly felled 10-year-old oil palm,Elaeis quineensis (Jacq.), were placed in a modified Nalgene desiccator, and volatiles captured for six days on Porapak Q. Gas chromatographic (GC) analysis of ...
Efficient syntheses of streptocarpone and (±)-a-dunnione
An efficient divergent synthesis of both streptocarpone and racemic α-dunnione from lawsone are described. A one-pot, formal [3+2] cyclization to form a furanonaphthoquinone directly provided a common intermediate.
Synthesis of 2-hydroxy-3-substituted naphthoquinones using the Heck reaction
An efficient Heck coupling of 2-hydroxy-3-iodo-naphthoquinone with a series of electron-deficient alkenes in aqueous solution has been accomplished. The method is characterized by simple conditions and facile work-up to ...