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A methane sink in the Central American high elevation páramo: Topographic, soil moisture and vegetation effects
(Elsevier B.V., 2020-03-15)Methane (CH4) is a strong greenhouse gas with a global warming potential 23 times larger than that of carbon dioxide. Characterizing ecosystems as either sources or sinks for methane and their magnitudes informs on biosphere ... -
A preliminary isotope-based evapotranspiration partitioningapproach for tropical Costa Rica
(John Wiley and Sons Ltd, 2021-07)Spatially and seasonally distributed information on transpiration (T) fluxes is limited in the tropics. Here, we applied a coupled isotope mass balance model to separate water fluxes of T and evapotranspiration (ET) from ... -
Addition of nanosilicas with different silanol content to thermoplastic polyurethane adhesives
(Elsevier, 2005-08-15)Three nanosilicas with different silanol contents were prepared by treatment of hydrophilic fumed silica with dimethyldichlorosilane. This treatment reduced the silanol content and produced the particle agglomeration of ... -
An approach to rheological and electrokinetic behaviour of lipidic vesicles covered with chitosan biopolymer
(Elsevier, 2008)The rheological and electrokinetic properties of soybean lecithin vesicles prepared from concentrated soy lecithin dispersions (250 g/L) obtained by slow swelling under shear conditions and mixed with chitosan biopolymer ... -
Analysis of energy transfer and ternary non-covalent filler/matrix/UV stabilizer interactions in carbon nanofiber and oxidized carbon nanofiber filled poly(methyl methacrylate) composites
(Elsevier, 2011-10-27)Ternary non-covalent interactions between carbon nanofibers (CNFs), oxidized carbon nanofibers (ox- CNFs), poly(methyl methacrylate) (PMMA) chains, and benzotriazole-containing UV stabilizers were analyzed using ... -
Analysis of non-covalent interactions between the nanoparticulate fillers and the matrix polymer as applied to shape memory performance
(The Royal Society of Chemistry, 2010)Non-covalent interactions between filler particles and polyurethanes were investigated using fluorescence emission spectroscopy. The results were used in the analysis of shape memory (SM) performance of polyurethanes. ... -
Anthrone and oxanthrone C,O-diglycosides from Picramnia teapensis
(Elsevier, 2000)Two C,O-diglycosylated compounds, the anthrone picramnioside F, and the oxanthrone mayoside C, were isolated from the stem bark of Picramnia teapensis, along with the previously reported anthraquinones, 1-O-b-d- and ... -
Antimicrobial activities of Marcgraviaceae species and isolation of a naphthoquinone from Marcgravia nervosa (Marcgraviaceae)
(NRC Research Press, 2015)The Marcgraviaceae is a neotropical plant family of lianas and shrubs distributed throughout Central and South America, mainly in evergreen and semi-evergreen tropical forests. In this study, extracts of 12 Marcgraviaceae ... -
Arsenate removal by chitosan iron oxyhydroxide beads: Preparation, characterization, and adsorption studies
(Desalination Publications, 2021)This study compared arsenic removal from drinking water by two different adsorbents: iron-im-pregnated chitosan beads (Fe-ICB) and iron-doped chitosan beads (Fe-dCB). Scanning electron microscopy, X-ray diffraction (XRD), ... -
Arthropod biodiversity loss and the transformation of a tropical agro-ecosystem
(Chapman & Hall, 1997)The coffee (coffea arabica) agro-ecosystem in the Central Valley of Costa Rica was formerly characterized by a high vegetational diversity. This complex system has been undergoing a major transformation to capital-intensive ... -
Biofabrication of Gold Nanotriangles Using Liposomes as a Dual Functional Reductant and Stabilizer
(American Chemical Society, 2021-03-23)Negatively charged liposomes accomplished both functions as a reducing and stabilizing agent in the synthesis of gold nanotriangles (GNTs). Liposomes are based on a mixture of phospholipids phosphatidylcholine/phosphoglycerol, ... -
Biogardens as constructed wetlands in tropical climate: A case study in the Central Pacific Coast of Costa Rica
(Elsevier, 2019-03-25)In Costa Rica, <10% of wastewater is treated before its discharge. This generates a significant impact on the environment, public health, and tourism industry, which is one of the country's main economic activities. ... -
Characterization and applications of silver nanoparticles-decorated electrospun nanofibers loaded with polyphenolic extract from rambutan (Nepelium lappaceum)
(Elsevier B.V., 2020-05)Rambutan (Nephelium lappaceum) is a traditional fruit originally from Asia and now widely available in Central America. The rind of rambutan is rich in antioxidants, especially polyphenols, which have natural anti-inflammatory ... -
Chemical constituents from Zanthoxylum setulosum (Rutaceae)
(Universidad Nacional, Costa Rica, 2011-02-10)Following our phytochemical studies of Costa Rican plants, in this work we report the isolation and identification of eight compounds from aerial parts of Zanthoxylum setulosum (Rutaceae). They were identified as the ... -
Composite soy lecithin–decylpolyglucoside vesicles: A theoretical and experimental study
(Elsevier, 2008)In the present work, vesicles made with soy lecithin and a commercial mixture of alkyl polyglucosides were prepared and characterized. Vesicles with a constant amount of soy lecithin and an increasing amount of a ... -
Composites of carbon nanofibers and thermoplastic polyurethanes with shape-memory properties prepared by chaotic mixing
(Wiley Inter Science, 2009)Composites of carbon nanofibers (CNFs), oxidized car bon nanofibers (ox-CNFs), and shape-memory thermo plastic polyurethane (TPU) were prepared in a chaotic mixer and their shape-memory properties evaluated. The polymer ... -
Effect of the soft segment on the fatigue behavior of segmented polyurethanes
(Elsevier, 2000)Effect of the soft-segment structure and molecular weight on the microphase separation in segmented polyurethanes (SPU) was determined by means of differential scanning calorimetry, small-angle X-ray scattering, dielectric ... -
End member and Bayesian mixing models consistently indicate near-surface flowpath dominance in a pristine humid tropical rainforest
(John Wiley & Sons Ltd, 2021)The impacts of forest conversion on runoff generation in the tropics have received much interest, but scientific progress is still hampered by challenging fieldwork conditions and limited knowledge about runoff mechanisms. ... -
Enhancing the tolerance of Clostridium saccharoperbutylacetonicum to ligno‐ cellulosic-biomass-derived inhibitors for efficient biobutanol production by overexpressing efflux pumps genes from Pseudomonas putida
(Elsevier Ltd, 2020)Furan aldehydes and phenolic compounds generated during biomass pretreatment can inhibit fermentation for biofuel production. Efflux pumps actively transport small molecules out of cells, thus sustaining normal microbial ... -
Fungal biosynthesis of lignin-modifying enzymes from pulp wash and Luffa cylindrica for azo dye RB5 biodecolorization using modeling by response surface methodology and artificial neural network
(Elsevier, 2020-06-04)This study demonstrates the evaluation between the artificial neural network technique coupled to the genetic algorithm (ANN-GA) and the response surface methodology (RSM) for prediction of Reactive Black 5 (RB5) decolorization ...