Listar Química por título
Mostrando ítems 285-304 de 360
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Residuos, Degradación y Persistencia del Fungicida Maneb en Patatas en Costa Rica
(1983)Residues of the fungicide maneb (manganese-1,2-ethylen-bisdithiocarbamate) were analyzed by the carbondisulfide evolution method in samples of potatoes, potato leaves and soil from a commercial crop located in Llano Grande ... -
Residuos, sorción y desorción del herbicida paraquat en suelos tropicales
(1987-11-24)Se analizaron por espectrofotometría residuos del herbicida Paraquat en muestras de suelos tropicales de Costa Rica dedicados al cultivo del café y donde el Paraquat es aplicado desde hace alrededor de 20 años, una o dos ... -
Richness and metallo-tolerance of cultivable fungi recovered from three high altitude glaciers from Citlaltépetl and Iztaccíhuatl volcanoes (Mexico)
(2020)In Mexico little is known about high-altitude glacial psychrotolerant or psychrophilic fungal species, with most glacial fungi isolated from polar environments or Alpine glaciers. It has been documented that some of these ... -
Room temperature gas-solid reaction of titanium on glass surfaces forming a very low resistivity layer
(2016-09)Titanium films were deposited on quartz, glass, polyamide and PET substrates in a high vacuum system at room temperature and their electrical resistance monitored in vacuo as a function of thickness. These measurements ... -
Screening of Latin American Plants for Cytotoxic Activity
(2006)The SRB cytotoxicity assay was used to screen plant extracts, in a collaborative multinational OAS project involving Argentina, Bolivia, Colombia, Costa Rica, Guatemala, Nicaragua and Panama, against breast (MCF-7), lung ... -
Seco-manool and other constituents from fleischmannia microstemon
(1988-01)The aerial parts of Fleischmannia microstemon afforded in addition to sesamin and two clerodanes, ent-manoyl oxide and two derivatives of the latter, one a 6β-acetoxy derivative and the other a seco-labdane. From F. pratensis ... -
Sekikaic Acid and Lobaric Acid Target a Dynamic Interface of the Coactivator CBP/p300
(2012-10-08)Although there have been recent notable successes in thediscovery of ligands that target stable, high-affinity protein-protein interactions (PPIs), the transient and moderateaffinity PPIs that underpin many fundamental ... -
Separation of crude plant extracts with high speed CCC for primary screening in drug discovery
(2001)High speed countercurrent chromatography (HSCCC) was used in a pre-fractionation pilot study to improve the quality of crude plant samples for primary screening in drug discovery efforts. The methanol ... -
Sesquiterpene lactones and other constituents from Calea prunifolia and C. Peckii
(1989)A re-investigation of Calea prunifolia afforded, in addition to compounds reported previously, a new eudesmanolide, a costol acetate hydroperoxide and four aromatic compounds. Calea peckii gave a large variety of aromatic ... -
Sex pheromone components of Diatraea considerata (Heinrich) (Lep., Pyralidae)
(1998-08)Three aldehydes. (Z)-11-hexadecenal (Z11–16:Ald), (Z)-7-hexadecenal (Z7–16:Ald) and (Z)-13-octadecenal (Z13–18:Ald), in a ratio of 74:23:3 are female-produced sex pheromone components of the pyralid moth, Diatraea considerata ... -
Short communication: Effect of different kefir grains on the attributes of kefir produced with milk from Costa Rica
(2020)Kefir is an artisanal product that is gaining scientific attention due to its increase in consumption attributed to its potential health benefits. The effect on the quality attributes of kefir grains of different origin ... -
Síntesis de derivados de la fenantrenoquinona con compuestos difuncionales
(1978)En este trabajo se comparó la reactividad del grupo metileno (-CH2-) en reacciones de condensación. Cuando el grupo metileneo está entre dos grupos carbonilos (compuestos 1,3-dicarbonílicos) la reactividad es mayor como ... -
Síntesis de la feromona sexual de la polilla de la papa, Scrobipalpopsis Solanivora
(1988)Se sintetizó el acetato (E) -3- dodecenilo, atrayente sexual de la polilla de la papa (Scrobipalpopsis solanivora), utilizando dos procedimientos: una ruta acetilénica y mediante la condensación de Knoevenagel. -
Síntesis de nuevas Dibenzo[f,h]cinolinas
(1985)Synthesis of new Dibenzo[f,h]cinnolines. Condensation of the compounds 9-acetonyl-9-hydroxy-10-oxo-9,10-dihydrophenanthrene (2) and 9-(2-cyclopentanonyl)-9-hydroxy-10-oxo-9,10-dihydrophenanthrene (3) with hydrazine produced ... -
Síntesis y caracterización de precursores moleculares de fuente única de bismuto con ligandos que contienen átomos dadores de oxígeno y azufre: generación de materiales conductores transparentes
(2024)La búsqueda por la generación de complejos metálicos, cuya obtención esté basada en un diseño planificado y racional, realizando variaciones estructurales a partir de distintas rutas sintéticas y deseando tener control ... -
Síntesis y evaluación de complejos de cobre (I/II) con ligandos polipiridínicos como mediadores redox en celdas solares sensibilizadas con tintes
(2020)En las celdas solares sensibilizadas con tintes (DSSCs), el mediador redox en el electrolito permite la transferencia de cargas al regenerar las moléculas del tinte durante su operación. Se sintetizaron y caracterizaron ...