Browsing Escuela de Química by Title
Now showing items 269-288 of 412
-
Increased fibroblast metabolic activity of collagen scaffolds via the addition of propolis nanoparticles
(MDPI AG, 2020-07-13)Propolis natural extracts have been used since ancient times due to their antioxidant, anti-inflammatory, antiviral, and antimicrobial activities. In this study, we produced scaffolds of type I collagen, extracted from ... -
Indicadores como insumo para la gestión integrada del recurso hídrico en la subcuenca del Río Uruca, cuenca del Río Grande de Tárcoles
(Universidad Nacional (Costa Rica), 2007)El mercado mundial de enzimas es de 1,4 billones de dólares al año, siendo las celulasas actualmente un grupo de enzimas de gran importancia debido a su utilización para la transformación de la celulosa en etanol. Existen ... -
Influence of iron oxide nanoparticles on the rheological properties of hybrid chitosan ferrogels
(Elsevier, 2009)Magnetite nanoparticles have been successfully synthesized in the presence of chitosan using an in situ coprecipitation method in alkali media. This method allows obtaining chitosan ferrogels due to the simul taneous ... -
Influence of the electrical interface properties on the rheological behavior of sonicated soy lecithin dispersions
(Universidad Nacional (Costa Rica), 2007)A significant effect, on the rheological behavior, due to the electrical properties of vesicles formed from concentrated soy lecithin dispersions have been studied in this work. The rheopectic behavior of concentrated soy ... -
Influencia de la actividad volcánica y antropogénica en la composición química de la lluvia de los alrededores del Volcán Poás, Costa Rica.
(Universidad Nacional (Costa Rica), 2000)En este trabajo se describen los resultados de un estudio sobre las características fisicoquímicas del agua de lluvia de los alrededores del Volcán Poás. El objetivo principal fue establecer un perfil general de los ... -
Initial validation of ozone measurements from the High Resolution Dynamics Limb Sounder
(Advancing earth an space science, 2008)Comparisons of the latest High Resolution Dynamics Limb Sounder (HIRDLS) ozone retrievals (v2.04.09) are made with ozonesondes, ground-based lidars, airborne lidar measurements made during the Intercontinental Chemical ... -
Insight into the stable isotopic composition of glacial lakes in a tropical alpine ecosystem: Chirripó, Costa Rica
(Wiley & Sons, 2018)Tropical high‐elevation lakes are considered sentinels of global climate change. This work characterizes the hydrological conditions of tropical alpine glacial lakes located in the highlands of Chirripó, Costa Rica, using ... -
Inventario de emisiones de mercurio en Costa Rica en el 2014 utilizando la herramienta del PNUMA en un nivel N2
(Universidad Nacional (Costa Rica), 2018)El Convenio de Minamata se firmó en octubre del 2013 buscando proteger la salud humana y el medio ambiente de las liberaciones y emisiones antropogénicas tanto de mercurio elemental como de los compuestos que contienen ... -
Inventario de gases de efecto de invernadero debidos al sector desechos, en el cantón de San Pablo de Heredia
(Universida Nacional, 2021-06-21)Se presenta en este informe la estimación de los gases de efecto invernadero (GEI) generados por la categoría de inventario correspondiente a residuos sólidos, en el Cantón de San Pablo de Heredia, para el año 2018. En el ... -
Inventario nacional de las emisiones antropogénicas de mercurio, utilizando la metodología propuesta por el PNUMA, para el establecimiento de políticas nacionales e internacionales relacionadas con el control de las emisiones, Costa Rica, 2008
(Universidad Nacional (Costa Rica), 2015-02)Se realizó un Inventario Nacional de las Emisiones de Mercurio para Costa Rica en el 2008 utilizando el Nivel 1 de dicha herramienta. La metodología se desarrolló en 3 etapas en la que primero se efectuó la búsqueda de la ... -
Inventario preliminar de emisiones atmosféricas (SO2, NOx y PTS) de diferentes sectores industriales en Costa Rica
(Universidad Nacional (Costa Rica), 2021-01-31)El uso de diversos combustibles, el incremento de la urbanización, y el desarrollo económico, han influido en la generación de contaminantes atmosféricos, tales como los NOx (óxidos de nitrógeno), el SO2 (dióxido de azufre) ... -
Investigating the impacts of biochar on water fluxes in 2 tropical agriculture using stable isotopes
(European Geosciences Union, 2020)Amending soils with biochar, a pyrolyzed organic material, is an emerging practice to potentially increase plant available water. However, it is not clear (1) to what extent biochar amendments increase soil water storage ... -
Irbesartan desmotropes: Solid-state characterization, thermodynamic study and dissolution properties
(Xi'an Jiaotong University, 2019-07-10)Irbesartan (IBS) is a tetrazole derivative and antihypertensive drug that has two interconvertible structures, 1H- and 2H-tautomers. The difference between them lies in the protonation of the tetrazole ring. In the ... -
Iridoids from the aerial parts of Verbena littoralis (Verbenaceae)
(Elsevier, 2004)The iridoids, 6S-hydroxy-8S-methyl-4-methylene-hexahydro-cyclopenta[c]pyran-3-one and 6S,9S-dihydroxy-8S-methyl-4- methylene-hexahydro-cyclopenta[c]pyran-3-one, were isolated from the aerial parts of Verbena littoralis. ... -
Isolation and Characterization of Nanocellulose Obtained from Industrial Crop Waste Resources by Using Mild Acid Hydrolysis
(Tech Science Press, 2018)Cellulose, microcrystalline cellulose and nanocellulose were prepared from three agricultural waste resources: pineapple leaf (PALF), banana rachis (BR), and sugarcane bagasse (SCB). Each waste resource was first converted ... -
Isolation and Characterization of Nanofibrillar Cellulose from Agave tequilana Weber Bagasse
(Hindawi Limited, 2019)The bagasse of Agave tequilana Weber is one of the most abundant agroindustrial wastes in the state of Jalisco. However, at the present time, there is no technical use for this waste, and its high availability makes it ... -
Isomerization of fatty acids: A cellular barrier mechanism in nanotechnology?
(Journal of Nanoscience and Nanotechnology Vol.17 1-9, 2017-01)This work is a kinetic study of the coupling reaction of 2-mercaptoethanol with methyl undecenoate and with methyl oleate through " click " chemistry. Reversibility and reactivity of each system were followed through Fourier ... -
Isotope hydrology and baseflow geochemistry in natural and human-altered watersheds in the Inland Pacific Northwest, USA
(2015-02-18)This study presents a stable isotope hydrology and geochemical analysis in the inland Pacific Northwest (PNW) of the USA. Isotope ratios were used to estimate mean transit times (MTTs) in natural and human-altered watersheds ... -
Isotope hydrology of a tropical coffee agroforestry watershed: Seasonal and event-based analyses
(Wiley & Sons, 2018)Stable isotope variations are extremely useful for flow partitioning within the hydrologic cycle but remain poorly understood throughout the tropics, particularly in watersheds with rapidly infiltrating soils, such as ... -
Isotopic composition in precipitation and groundwater in the northern mountainous region of the Central Valley of Costa Rica
(Taylor & Francis, 2016)The linkage between precipitation and recharge is still poorlyunderstood in the Central America region. This study focuses onstable isotopic composition in precipitation and groundwater in the northern mountainous region ...