Química
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Phytochemical study of endemic Costa Rican Annonaceae species Annona pittieri and Cymbopetalum costaricense
(2021)Phytochemical profile of the Central American rainforest endemic Annonaceae species, Annona pittieri and Cymbonopetallum costaricense, were studied in search of novel bioactive compounds. The acetogenin squamocin (1) ... -
Anti-platelet activity and chemical characterization by UPLC-DAD-ESI-QTOF-MS of the main polyphenols in extracts from Psidium leaves and fruits
(2021)In Costa Rica, two species of Psidium fruits, P. guajava and P. friedrichsthalianum, are widely consumed as food and used in folk medicine. Although studies have revealed the health effects of these fruits, there has been ... -
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 ... -
Methylotrophs and Hydrocarbon-Degrading Bacteria Are Key Players in the Microbial Community of an Abandoned Century-Old Oil Exploration Well
(2021-04-17)In this work, we studied the microbial community and the physicochemical conditions prevailing in an exploratory oil well, abandoned a century ago, located in the Cahuita National Park (Costa Rica). According to our analysis, ... -
Special Issue: Diversity of Extremophiles in Time and Space
(2021-11-30)Extreme environments are fascinating ecosystems that have allowed us to increase our knowledge about the evolutionary processes of life [1], develop new biotechnological applications (e.g., industrial applications of ... -
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 ... -
The potential of Pseudomonas for bioremediation of oxyanions
(2021-12)Non-metal, metal and metalloid oxyanions occur naturally in minerals and rocks of the Earth’s crust and are mostly found in low concentrations or confined in specific regions of the planet. However, anthropogenic activities ... -
Operando tracking of oxidation-state changes by coupling electrochemistry with time-resolved X-ray absorption spectroscopy demonstrated for water oxidation by a cobalt-based catalysts film
(2021)Transition metal oxides are promising electrocatalysts for water oxidation, i.e., the oxygen evolution reaction (OER), which is critical in electrochemical production of non-fossil fuels. The involvement of oxidation state ... -
Guía de mediación pedagógica para aprendizajes comunitarios: comités de agua transfronte- rizos, Costa Rica - Nicaragua : pedagogía social, estrategias para la optimización del uso del agua para consumo humano en las comunidades de La Trocha e Isla Chica en los Chiles, Alajuela
(2021)El equipo de profesores y profesoras de la Universidad Nacional y la Universidad de Costa Rica que elaboró esta guía conforma el proyecto de extensión y acción social universitaria: “Pedagogía social: estrategias para la ... -
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 ... -
Bioactivity of prenylated hydroxybenzoic acids from Piper garagaranum C. DC
(2022)A bio-assay guided fractionation of Piper garagaranum C. DC. led to the isolation of two prenylated hydroxybenzoic acids (1-2) with anti-inflammatory and cytotoxic activities. The anti-inflammatory action was determined in ... -
Transcriptional control of 2,4-dinitrotoluene degradation in Burkholderia sp. R34 bears a regulatory patch that eases pathway evolution
(2021-05)The dnt pathway of Burkholderia sp. R34 is in the midst of an evolutionary journey from its ancestral, natural substrate (naphthalene) towards a new xenobiotic one [2,4-dinitrotoluene (DNT)]. The gene cluster encoding ... -
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 ... -
Soil Fungal Community Composition Correlates with Site-Specific Abiotic Factors, Tree Community Structure, and Forest Age in Regenerating Tropical Rainforests
(2021)Successional dynamics of plants and animals during tropical forest regeneration have been thoroughly studied, while fungal compositional dynamics during tropical forest succession remain unknown, despite the crucial roles ... -
Low CyaA expression and anti‐cooperative binding of cAMP to CRP frames the scope of the cognate regulon of Pseudomonas putida
(2021-03)Although the soil bacterium Pseudomonas putida KT2440 bears a bona fide adenylate cyclase gene (cyaA), intracellular concentrations of 30,50-cyclic adenosine monophosphate (cAMP) are barely detectable. By using reporter ... -
Reconfiguration of metabolic fluxes in Pseudomonas putida as a response to sub-lethal oxidative stress
(2021-01-11)As a frequent inhabitant of sites polluted with toxic chemicals, the soil bacterium and plant-root colonizer Pseudomonas putida can tolerate high levels of endogenous and exogenous oxidative stress. Yet, the ultimate ... -
Orbitals in general chemistry, Part III: Consequences for Teaching
(2021)In Part III of this series, we undertake a critique of the nature of application of orbitals to describe or to explain the structure and the binding within molecules and materials. Teaching orbitals in introductory chemistry ... -
Orbitals in general chemistry, Part II: Mathematical Realities
(2021)In Part II of a three-part series, we discuss two factors absent from textbooks of general chemistry that are important in a discussion of teaching orbitals. First, atomic orbitals are shown systematically to comprise ... -
Orbitals in general chemistry, Part I: The great debate
(2020-08)In Part I of a three-part series, we present an objective survey of the technical literature discussing the inclusion of orbitals in highschool and post-secondary general chemistry. We start with the definition of orbitals. ... -
Norstictic Acid Is a Selective Allosteric Transcriptional Regulator
(2021-06-17)Inhibitors of transcriptional protein–protein interactions (PPIs) have high value both as tools and for therapeutic applications. The PPI network mediated by the transcriptional coactivator Med25, for example, regulates ...
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