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Influence of rice field agrochemicals on the ecological status of a tropical stream
(2016-01-15)
Many tropical countries contain a high density of protected ecosystems, and these may often be bordered by intensive agricultural systems. We investigated the chemical and ecological status of a stream connecting an area ...
Caracterización fisicoquímica del agua superficial en la subcuenca del río La Paz, San Ramón, Alajuela Costa Rica; como indicador del impacto ambiental por urbanismo en la zona
(2020)
El río La Paz es uno de los afluentes del río Barranca ubicado en el distrito Piedades Norte de San Ramón. Esta zona se caracteriza por ser montañosa de población rural en crecimiento, en la que se llevan a cabo actividades ...
Determinación colorimétrica de hierro en agua potable mediante la utilización de imágenes obtenidas con el teléfono celular
(2023-03-09)
La colorimetría de imágenes digitales se basa en la extracción de coordenadas de color de imágenes captadas con dispositivos como: escáneres, cámaras digitales y teléfonos celulares. El hierro es uno de los elementos más ...
Inhibition of granulocyte elastase activity by caffeic acid derivatives
(1999)
In former studies it was shown that bornyl derivates may contribute to the anti-inflamatory activity of some drugs, such as Verbesia turbacensis, Notopterygium incisum or Coreopsis mutica.
Unusual Microbial Xylanases from Insect Guts
(2004-06-07)
Recombinant DNA technologies enable the direct isolation and expression of novel genes from biotopes containing complex consortia of uncultured microorganisms. In this study, genomic libraries were constructed from microbial ...
Synthesis of Iodinated Naphthoquinones Using Morpholine-Iodine Complex
(Synthetic Communications Vol. 34, No. 18, pp. 3389–3397, 2004, 2004)
The efficient synthesis of 2‐hydroxy‐3‐iodo‐1,4‐naphthoquinone (3), 2‐amino‐3‐iodo‐1,4‐naphthoquinone (4), and 2‐iodo‐1,4‐naphthoquinone (5) have been developed using the parent naphthoquinone in combination with the ...
Studies of methamidophos-C-14 in Costa Rican vegetables and soils
(1984)
In order to see the effect of time lapse between the last application of methamidophos and harvesting insecticide was applied on lettuce plants (6,84 μCi in one experiment and 4,03 μCi in the other experiment). Analysis ...
Drying kinetics as Tool for the Assessment of Dynamic Porosity of Catalyst-Support Materials
(2018)
Critical drying fraction data (xc) were obtained for a series of porous materials, frequently used
as supports for heterogeneous catalysts. This kinetic parameter correlates well with the secondorder rate constants for ...
Potent nor-triterpenoid blockers of the voltage-gated potassium channel Kv1.3 from Spachea correae
(1998)
The isolation and structure elucidation of two novel nor-triterpenoid KV1.3 potassium channel blockers correolide and dehydrocorreolide from the Costa Rican tree Spachea correae are reported.
The first potent and selective ...
La estructura de la Diacetonafenantrenoquinona
(1971)
The substance, diacetonephenanthrenequinone, long believed to have structure I or II, is found to have structure IV according to modern spectroscopic methods and chemical behavior.