Now showing items 4741-4760 of 5098

    • Fuentes Pérez, Edwar; Pinochet, Hugo; Potin-Gautier, Martine; De Gregori, Ida (AOAC INTERNATIONAL, 2004-01)
      This stability of Sb(Ill) and Sb(V) species was studied during,single extraction from soils by water. EDTA, diluted H2SO4 and H3PO4, and oxalic acid/oxalate solutions, with and without ascorbic acid, were used as stabilizing ...
    • De Gregori, Ida; Fuentes Pérez, Edwar; Rojas, Mariela; Pinochet, Hugo; Potin-Gautier, Martine (ROYAL SOC CHEMISTRY, 2003-04)
      This paper reports a comparative study of the concentration of three important environmental elements that are often found together in mineral deposits and then associated with mining activities: copper, arsenic and antimony. ...
    • Rodríguez Melis, Alicia; Castro Montero, Eduardo; Salinas, M. C.; López, R.; Miranda, M. (AMER OIL CHEMISTS SOC A O C S PRESS, 2001-04)
      The objective of this study was to manufacture a shortening using chemical interesterification (IT) of tallow-sunflower oil blends to replace fish oil in the present formulation, which is now in short supply in Chile. The ...
    • Ahumada Torres, Aída Inés de Lourdes; Escudero, Paula; Carrasco Rimassa, María Adriana; Castillo, Gabriela; Ascar Estay, María Loreto; Fuentes Pérez, Edwar (ROYAL SOC CHEMISTRY, 2004)
      In Chile, the increasing number of plants for the treatment of wastewater has brought about an increase in the generation of sludge. One way of sludge disposal is its application on land; this, however involves some problems, ...
    • De Gregori, Ida; Pinochet, Hugo; Fuentes Pérez, Edwar; Potin-Gautier, Martine (ROYAL SOC CHEMISTRY, 2001)
      Two sensitive analytical atomic spectrometry methods, electrothermal atomic absorption spectrometry (ET-AAS) and hydride generation coupled to atomic fluorescence spectroscopy (HG-AFS), were optimized for determining total ...
    • Fuentes Pérez, Edwar; Pinochet, Hugo; De Gregori, Ida; Potin-Gautier, Martine (PERGAMON-ELSEVIER SCIENCE LTD, 2003-07-18)
      A sensitive atomic spectrometric method for the redox speciation analysis of antimony in soils is described. The method is based on the selective generation of stibine from Sb(III) in a continuous flow system using atomic ...
    • Fuentes Pérez, Edwar; Báez Contreras, María Estrella; Quiñones Maragliano, Adalí Verónica (ELSEVIER SCIENCE BV, 2008-10-17)
      A systematic study of the microwave-assisted extraction coupled to solid-phase extraction of nine organophosphorus pesticides (dimethoate, diazinon, pirimiphos methyl, parathion methyl, malathion, fenthion, chlorpyriphos, ...
    • Fellenberg, M. A.; Delporte Vergara, Carla; Backhouse Erazo, Nadine; Peña, I.; Speisky Cosoy, Hernán (FACTA-FUNDACIO ARNCO CIENCIA TECNOLOGIA AVICOLAS, 2008-10)
      The addition of antioxidants to broiler diets has been shown to enhance their antioxidant status. Since boldo (Peumus boldus Mol.) leaves contain highly antioxidant molecules, a dried extract of boldo (DEB) was added to ...
    • Maya Arango, Juan; Morello Casté, Antonio; Repetto Scaramelli, Yolanda; Rodríguez, Andrés; Puebla, P.; Caballero S., Esther; Medarde, M.; Núñez Vergara, Luis; Squella Serrano, Juan; Ortíz Yáñez, María Eugenia; Fuentealba, J.; San Feliciano, Arturo (ACADEMIC PRESS INC, 2001-09)
      Chagas' disease constitutes a therapeutic challenge because presently available drugs have wide toxicity to the host and are generally ineffective in the chronic stages of the disease. A series of oxazolo(thiazolo)pyridene ...
    • Núñez Vergara, Luis; Sturm Schaub, Juan; Olea Azar, Claudio; Navarrete Encina, Patricio; Bollo Dragnic, Soledad; Squella Serrano, Juan (HARWOOD ACAD PUBL GMBH, 2000)
      This paper deals with the reactivity of the nitro radical anion electrochemically generated from nitrofurantoin with glutathione. Cyclic voltammetry (CV) and controlled potential electrolysis were used to generate the nitro ...
    • Núñez Vergara, Luis; López Alarcón, Camilo; Navarrete Encina, Patricio; Atria Salas, Ana María; Camargo Grandón, Rodrigo; Squella Serrano, Juan (TAYLOR & FRANCIS LTD, 2003)
      This work reports the electrochemical oxidation of a series of three synthesized 4-substituted-1,4-dihydropyridine derivatives in different electrolytic media. Also, an EPR characterization of intermediates and the reactivity ...
    • Araya Maturana, Ramiro; Cassels Niven, Bruce; Delgado Castro, Tomás; Valderrama Guerrero, Jaime Adolfo; Weiss López, Boris (PERGAMON-ELSEVIER SCIENCE LTD, 1999-01-15)
      The Diels-Alder reactions of 8,8-dimethylnaphtalene-1,4,5(8H)-trione with 2,4-hexadien-1-ol and its O-acetyl derivative were investigated in different solvents. The regiochemistry of the cycloaddition of the hexadienol was ...
    • Castañeda Magliona, Fernando; Terraza, C. A.; Bunton, Clifford A.; Gillitt, N. D.; Garland, María Teresa (TAYLOR & FRANCIS LTD, 2003-09)
      The stabilized phosphorus ylides, Ph3P=C(CO.R')CO.OR, 1, R=Et, R' =CH2P+Ph3; 2, R=R'=Me; 3, R=Et, R'=Me; 4, R=Pr-i; R'=Me, 5, R=Bu-t; R'=Me, adopt a near planar conformation in the crystal which allows extensive electronic ...
    • Quijada Abarca, Juan; Guevara, Juan Luis; Yazdani-Pedram Zobeiri, Mehrdad; Galland, Griselda B.; Ribeiro, D. (SPRINGER-VERLAG, 2002-12)
      1-Octadecene (C18) was polymerized by using different metallocene catalysts. The rac-Et(Ind)(2)ZrCl2/MAO (I) and rac-Me2Si(Ind)(2)ZrCl2/MAO (III) presented the highest C, activity as compared with rac-Et(2-Me-Ind)(2)ZrCl2/MAO ...
    • Fuente, J. de la; Jullian Matthaei, Carolina; Saitz Barría, Claudio; Sobarzo Sánchez, Eduardo; Neira Pacheco, Verónica Alejandra; González, C.; López, R.; Pessoa Mahana, Hernán (ROYAL SOC CHEMISTRY, 2004)
      Photoreduction of 5,6-dimethoxy-, 5-methoxy- and 2,3-dihydro-7H-dibenzo[de, h] quinolin-7-one (A) by tertiary amines in oxygen-free solutions generates long-lived semi-reduced metastable photoproducts, A - NH-, via a ...
    • Castañeda Magliona, Fernando; Jullian Matthaei, Carolina; Bunton, Clifford A.; Garland, María Teresa; Baggio, Ricardo (International Union of Crystallography, 2007)
      Hydrogen bonding and crystal packing play major roles in determining the conformations of ethyl methyl 2-(triphenyl-phosphoranylidene)malonate, Ph3P=C(C02CH3)CO2CH2CH3 or C24H23O4P,(I), and dimethyl 2-(triphenylphosphora ...
    • Aguirre, María C.; Delporte Vergara, Carla; Backhouse Erazo, Nadine; Erazo, Silvia; Letelier Muñoz, María Eugenia; Cassels Niven, Bruce; Silva, Ximena; Alegría, Sergio; Negrete Córdova, Rosa (PERGAMON-ELSEVIER SCIENCE LTD, 2006-08-15)
      Leaf extracts of Ugni molinae Turcz. are used in the Chilean cosmetic industry on the assumption that they have decongestant, regenerative, and anti-aging properties. A bioassay-guided fractionation of this plant material ...
    • Delporte Vergara, Carla; Backhouse Erazo, Nadine; Inostroza, V.; Aguirre, María C.; Peredo, N.; Silva, X.; Negrete Córdova, Rosa; Miranda, Hugo (ELSEVIER IRELAND LTD, 2007-05-30)
      Leaf extracts of Ugni molinae Turcz. (Myrtaceae) are used in Chilean folk medicine as analgesic and anti-inflammatory. The antinociceptive effect of dichloromethane (I)CM), ethyl acetate (EA) and methanol (ME) leaf extracts ...
    • Ureta Zañartu, María Soledad; Yáñez Soto, Claudia; Páez, Maritza; Reyes Cava, Gloria Ximena (ELSEVIER SCIENCE SA LAUSANNE, 1996-04-12)
      The activity of Pt, Pt + Pb and Pt + Ir deposits on Ti, for ethylene glycol (EG) oxidation, was studied in both 0.5 M H2SO4 and 0.5 M NaOH solutions. The metallic deposits were prepared by electrolysis at constant current ...
    • Castañeda Magliona, Fernando; Bunton, Clifford A.; Baggio, Ricardo; Garland, María Teresa (BLACKWELL PUBLISHING, 2007-01)
      Crystalline cyano-stabilized triphenylphosphonium ylids with keto or ester groups give rise to an extended electronic delocalization. In methyl 2-cyano-2-(trimethylphosphonio)-ethenoate, Ph3P=C(CN)CO2CH3 or C22H18NO2P, ...