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Mostrando ítems 164-183 de 360
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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 ... -
Flavonoid and other constituents of Bauhinia manca
(1988)Phytochemical analysis of the stem of Bauhiniu munca yielded 63 compounds, among them six new natural products. Major constitutents were found to be 3-0-galloylepicatechin, gallic acid, cinnamic acid, /3-sitosterol and its ... -
Focos de Innovación 2024-2025
(2024-02-21)Es evidente que las transformaciones ambientales, sociales y económicas, que son necesarias para el desarrollo a nivel global, dependen de las soluciones novedosas que la ciencia, la tecnología y la innovación puedan ... -
Fotorreducción de dióxido de carbono usando TiO2 sensibilizado con trímeros de Co y Cu en medio acuoso
(2021-01-31)En la presente investigación, se evaluó el desempeño de dos fotocatalizadores de dióxido de titanio, uno sensibilizado con un trímero de cobre (Cu3(dpa)4Cl2) (dpa = 2,2 ́-dipiridilamina) y el otro con un trímero de cobalto ... -
From Ideality to Simplicity: A Robust and Affordable Hydrogen Reference Electrode
(2020-02-01)In electrochemistry, the concept of a reference electrode is fundamental. Introductory courses might mention the standard hydrogen electrode (SHE), its working principle, and its theoretical design; however, chances are ... -
Fundamentos de Química Orgánica
(1985)Este libro es una introducción a la Química Orgánica, para estudiantes de carreras médicas, Microbiología, Biología, Agricultura, Veterinaria. Llena un vacío entre textos escolares y libros de texto de la carrera de Química. -
Fungi with history: Unveiling the mycobiota of historic documents of Costa Rica
(2022-06-12)Through nondestructive techniques, we studied the physicochemical characteristics and mycobiota of five key historic documents from Costa Rica, including the Independence Act of Costa Rica from 1821. We determined that for ... -
Fusarium: more than a node or a foot-shaped basal cell
(2021)Recent publications have argued that there are potentially serious consequences for researchers in recognising distinct genera in the terminal fusarioid clade of the family Nectriaceae. Thus, an alternate hypothesis, namely ... -
Gaschromatographische Analyse des Samenfettes der mittelamerikanischen Fevillea Cordifolia (Cucurbitaceae)
(1992)The fat of the seeds of Fevillea cordifolia was extracted under exclusion of oxygen and light and then characterized by 13C-NMR in regard to the contained unsaturated acid moieties. The total fat was separated by HPLC to ... -
General Chemistry Without Orbitals
(2020)We illustrate the solutions of Schroedinger's equation for the hydrogen atom in coordinates of all four systems, and differentiate the applicability of orbitals in these four systems. We present reasons that future textbooks ... -
Germacranolides and other constituents from ageratzna species
(1988)The aerial parts of Ageratina anisochroma gave several thymol derivatives including five new ones, a hydroxypiperitol glucoside, some substituted benzyl benzoates and several germacranolides related to provincialin. From ... -
Germacranolides from Mikania guaco
(2001-03)Fourteen novel sesquiterpene lactones of the germacranolide type have been isolated from the aerial parts of Mikania guaco: six costunolide, two melampolide and six germacra-4-trans,10(14),11(13)-trien-12,6α-olide derivatives. ... -
Granular Activated Carbon Treatment May Result in Higher Predicted Genotoxicity in the Presence of Bromide
(2016-07-28)Certain unregulated disinfection byproducts (DBPs) are more of a health concern than regulated DBPs. Brominated species are typically more cytotoxic and genotoxic than their chlorinated analogs. The impact of granular ... -
Grids II: Aromatic Acidity and Basicity
(2021)The effect of substituents on the acidity of benzoic acids and basicity of anilines has been organized in grids to demonstrate the inductive and resonance effects. The relation between structure and pKa is emphasized ... -
Grids III: Hydrogen Bridges in Introductory Chemistry
(2021)Based on IUPAC recommendations for the definition of the hydrogen bond, a series of grids is presented to provide instructors of introductory chemistry courses with visual examples of H-bridged systems. The grids ... -
Guía de lectura de la Base de Datos para el Estudio de Inteligencia Tecnológica y Científica del Cannabidiol (CBD)
(2023)El Excel cuenta con 3 hojas, donde la primera corresponde a Artículos Científicos, la segunda a Patentes y la última a CIP detalle, las cuales son las siglas para Código Internacional de Patentes. De esta manera, en cada ...