Browsing Artículos científicos by Title

Now showing items 105-124 of 188

    • Hacia una gestión de reactivos y residuos químicos en los laboratorios de docencia de la Escuela de Química en la Universidad Nacional 

      Benavides Benavides, Ana Cristina; Vargas Gonzalez, Xinia; Chaves Barboza, Gustavo; Rodríguez Corrales, José Ángel (Universidad Nacional (Costa Rica), 2012)
      Las actividades académicas que se realizan en la Escuela de Química hacen indispensable la puesta en marcha de acciones orientadas a la consolidación de una gestión de los reactivos y residuos, especialmente en los ...

    • Headwaters drive streamflow and lowland tracer export in a large-scale humid tropical catchment 

      Birkel, Christian; Correa, Alicia; Martinez Martinez, Marco; Granados-Bolaños, Sebastián; Venegas Cordero, Nelson; Gutiérrez-García, Kenneth; Blanco-Ramírez, Sara; Quesada-Mora, Rafael; Solano-Rivera, Vanessa; Mussio-Mora, Jasson; Chavarría-Palma, Andrés; Vargas-Arias, Katherine; Moore, Georgianne W.; Durán-Quesada, Ana María ; Vasquez Morera, Javier; Soulsby, Chris; Tetzlaff, Dorthe; Espinoza-Cisneros, Edgar; Sanchez-Murillo, Ricardo (John Wiley and Sons Ltd, 2020)
      Headwaters are generally assumed to contribute the majority of water to downstream users, but how much water, of what quality and where it is generated are rarely known in the humid tropics. Here, using monthly monitoring ...

    • Hydrogeological responses in tropical mountainous springs 

      Salas-Navarro, Jessica; Sanchez-Murillo, Ricardo; Esquivel-Hernández, Germain; Corrales Salazar, José Leonardo (Taylor and Francis Ltd., 2018)
      This study presents a hydrogeochemical analysis of spring responses (2013–2017) in the tropical mountainous region of the Central Valley of Costa Rica. The isotopic distribution of δ18O and δ2 H in rainfall resulted ...

    • Hydrological dataset of a sub-humid continental plain basin (Buenos Aires, Argentina) 

      Zabala, María Emilia; Sanchez-Murillo, Ricardo; Dietrich, Sebastián; Gorocito, Martin; Vives, Luis; Manzano, Marisol; Varni, Marcelo (Elsevier, 2020)
      The Chaco-Pampean Plain (Argentina) is the strongest eco- nomic region and the most inhabited in the country, comprising approximately 66% of the country’s population (26,500 million) [1] . In this region, surface slopes ...

    • Identificación de explosivos Orgánicos en Indicios Post-Explosión mediante GC-MS y GC-NPD 

      Arce-Rubí, Stephanie; Vargas-Ramírez, Steven; Solís-Montiel, Efraín; Piedra-Marin, Gilberto; mora barrantes, jose carlos; Sibaja, José; Borbon Alpizar, Henry (Tecnológico de Costa Rica, 2020-07)
      Se implementó y validó un método para la identificación de explosivos por medio de cromatografía de gases acoplada a un detector de espectrometría de masa (GC-MS) y por cromatografía de gases de doble columna acoplada a ...

    • Identificación de lignanas en hojas de Rollinia mucosa (JACQ) bail. Annonaceae 

      Villegas, Juan R.; Calvo, Marco; Castro-Gamboa, Ian; Castro, Óscar (Universidad Nacional (Costa Rica), 2001)
      El extracto etanólico obtenido por maceración de las hojas de Rollinia mucosa fue extraído sucesivamente con los siguientes disolventes de polaridad creciente: hexano, cloroformo y acetato de etilo. Diluciones alcohólicas ...

    • Identification and Investigation of Autolysin Genes in Clostridium saccharoperbutylacetonicum Strain N1-4 for Enhanced Biobutanol Production 

      Jiménez-Bonilla, Pablo; Feng, J.; Wang, S.; Zhang, Jie; Wang, Yifen; Blersch, David; de-Bashan, Luz; Gaillard, Philippe; Guo, Liang; Wanga, Yi (American Society for Microbiology, 2021-03-11)
      Biobutanol is a valuable biochemical and one of the most promising biofuels. Clostridium saccharoperbutylacetonicum N1-4 is a hyperbutanol-producing strain. However, its strong autolytic behavior leads to poor cell stability, ...

    • Identifying groundwater recharge connections in the Moscow (USA) sub-basin using isotopic tracers and a soil moisture routing model 

      Candel, Jasper; Brooks, Erin; Sánchez-Murillo, Ricardo; Grader, George; Dijksma, Roel (Springer, 2016)
      Globally, aquifers are suffering from large abstrac tions resulting in groundwater level declines. These declines can be caused by excessive abstraction for drinking water, irrigation purposes or industrial use. Basaltic ...

    • Impacto nacional e internacional en la promoción de las vocaciones científicas del Programa Mejoramiento de la Enseñanza de la Química(PMEQ) 

      Syedd-León, Randall; Madrigal, Ana Rocío; Sandoval B., Manuel; Vega-Baudrit, José (Universidad Nacional (Costa Rica), 2013)
      La labor extensionista de la Escuela de Química de la UNA en Costa Rica se ha visto reflejada desde sus inicios, en gran medida, por las actividades realizadas desde el Programa de Mejoramiento de la Enseñanza de la ...

    • Increased fibroblast metabolic activity of collagen scaffolds via the addition of propolis nanoparticles 

      González Masís, Jeimmy; Cubero-Sesin, Jorge M.; Corrales Ureña, Yendry; González Camacho, Sara; Mora-Ugalde, Nohelia ; Baizán , Mónica ; Loaiza, Randall; Jose-Roberto, Vega-Baudrit; González Paz, Rodolfo (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 ...

    • Influence of iron oxide nanoparticles on the rheological properties of hybrid chitosan ferrogels 

      Hernández, Rebeca; Zamora-Mora, Vanessa; Sibaja-Ballestero, María; Vega-Baudrit, José; López, Daniel; Mijangos, Carmen (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 

      Alvarez, M.A.; Seyler, D.; Madrigal-Carballo, Sergio; Vila, A.O.; Molina, F. (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 ...

    • Initial validation of ozone measurements from the High Resolution Dynamics Limb Sounder 

      Nardi, Bruno; Gille, John C.; Barnett, John J.; Randall, Cora E.; Harvey, V. Lynn; Waterfall, Alison; Reburn, W. Jolyon; Leblanc, Thierry; McGee, Tom J.; Twigg, Laurence W.; Thompson, Anne Mee; Godin-Beekmann, Sophie; Bernath, Peter F.; Bojkov, Bojan R.; Boone, Chris D.; Cavanaugh, Charles; Coffey, Michael T.; Craft, James; Craig, Cheryl; Dean, Vincil; Eden, Thomas D.; Francis, Gene; Froidevaux, Lucien; Halvorson, Chris; Hannigan, James; Hepplewhite, Christopher L.; Kinnison, Douglas E.; Khosravi, Rashid; Krinsky, Charlie; Lambert, Alyn; Hyunah, Lee; Joanne, Loh; Massie, Steven T.; McDermid, I. Stuart; Packman, Daniel; Torpy, Brendan; Valverde-Canossa, Jessica; Walker, Kaley A.; Whiteman, David N.; Witte, Jacquelyn C.; Young, Greg (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 

      Esquivel-Hernández, Germain; Sanchez-Murillo, Ricardo; Quesada-Román, Adolfo; Mosquera, Giovanny; Birkel, Christian; Ball, Jan (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 

      Murillo Hernández, Julio César; Herrera-Murillo, Jorge; Sibaja, José (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 preliminar de emisiones atmosféricas (SO2, NOx y PTS) de diferentes sectores industriales en Costa Rica 

      Alfaro, Daniel; Salas-Morelli, Luis; Sánchez, Bryan; Mora-Barrantes, José; Sibaja, José; Borbón-Alpízar, Henry (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) ...

    • Irbesartan desmotropes: Solid-state characterization, thermodynamic study and dissolution properties 

      Araya Sibaja, Andrea Mariela; Campos, Carlos Eduardo de; Fandaruff, Cinira; Jose-Roberto, Vega-Baudrit; Guillen-Girón, Teodolito; Navarro-Hoyos, Mirtha; Cuffini, Silvia Lucia (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) 

      Castro-Gamboa, Ian; Castro, Oscar (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 

      Moreno, Galia; RAMÍREZ-AMADOR, KARLA ; ESQUIVEL ALFARO, MARIANELLY; Jiménez Villalta, Guillermo (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 

      Palacios, Hasbleidy; Hernandez Diaz, Javier A.; ESQUIVEL ALFARO, MARIANELLY; Toriz, Guillermo; Rojas, Orlando; Sulbaran Rangel, Belkis (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 ...