Browsing Química by Title
Now showing items 149-168 of 360
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Ethyl 5-[(ethoxycarbonyl)oxy]-5,5-diphenylpent-2- ynoate
(2019-11-12)The title compound, C 22 H22 O 5, crystallizes with two molecules in the asymmetric unit, one of which shows disorder of its ethyl acetate group over two sets of sites in a 0.880 (2):0.120 (2) ratio. The C C distances ... -
Ethyl propionate: Synergistic kairomone for african palm weevil,Rhynchophorus phoenicis L. (Coleoptera: Curculionidae)
(1994-04)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 ... -
Evaluación de la capacidad del cemento Portland dopado con nanopartículas de TIO2 para la disminución de Pseudomonas aeruginosa y Escherichia coli en agua
(2022-10)El abastecimiento de agua potable no es equitativo para la población mundial y este problema empeora debido al crecimiento poblacional, a la contaminación, al calentamiento global y a un inadecuado tratamiento de potabilización. ... -
Evaluación de los efectos de la contaminación atmosférica y el ángulo de exposición sobre la corrosión del acero de bajo carbono y acero galvanizado en la región del Valle Central Occidental (VCO) de Costa Rica
(2023-05)Costa Rica is a country that imports its metallic materials, this makes the evaluation of its corrosion losses of special interest, since they represent an average of 3% of the GDP. In particular, atmospheric corrosion is ... -
Evaluation of a recent product to remove lipids and other matrix co-extractives in the analysis of pesticide residues and environmental contaminants in foods
(2016-06-03)This study demonstrates the application of a novel lipid removal product to the residue analysis of 65 pesticides and 52 environmental contaminants in kale, pork, salmon, and avocado by fast, low pressure gas chromatography ... -
Evolution of the reactive surface area of ferrihydrite: time, pH, and temperature dependency of growth by Ostwald ripening
(2019-02)Surface area is a crucial property of metal oxides for scaling ion adsorption phenomena. For ferrihydrite (Fh), the value is uncertain. Moreover, it rapidly changes with time, pH, and temperature. In this study, the dynamic ... -
Expanding the Trichoderma harzianum species complex: Three new species from Argentine natural and cultivated ecosystems
(2021-06-22)A study was performed on a collection of 84 isolates from decaying plant tissues and soils in Argentina previously identified as Trichoderma harzianum. Based on multiple phenotypic characters and multilocus phylogenetic ... -
Experimental and theoretical studies of C–H⋯M interactions in palladium and platinum complexes derived from 1,2-bis-(2-hydroxymethylphenylthio)ethane
(2015-02)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 ... -
Fate of buturon-14C in soil during seven seasons of exposure under outdoor conditions
(1984-03)Buturon (ring 14C) was applied to wheat and soil in two successive years (3 kg/ha each year) at outdoor conditions. Residual radioactive substances in the upper soil layer (0-10-cm depth) were measured 1.5, 2.5, 3.5, 6.0, ... -
Fevicordin A and Fevicordin A Glucoside, Novel Norcucurbitacins from Fevillea cordifolia
(1987)From the seeds of the Central American Fevillea cordifolia (Cucurbitaceae) fevicordin A glucoside (1) and fevicordin A (2) members of the novel norcucurbitacin group, were isolated. -
Field trip to Costa Rica: The search for cobalt!
(2016-06-27)Este blog describe las actividades académicas de los integrantes del Geomicro Group de la University of Manchester, Reino Unido, liderado por el Prof. Jonathan Lloyd. Esta publicación en particular, fue escrita por Agustín ... -
Fisico-química de las aguas superficiales de la Cuenca del río Rincón, Península de Osa, Costa Rica
(2010-12)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 ...