Artículos científicos
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Ítem Nanochitin and Nanochitosan in Pharmaceutical Applications: Innovations, Applications, and Future Perspective(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2025) Jose-Roberto, Vega-Baudrit; Lopretti, Mary; Montes de Oca, Gabriela; Camacho, Melissa; Batista, Diego; Corrales, Yendry; Araya, Andrea; Bahloul, Badr; Corvis, Yohann; Castillo-Henríquez, LuisAbstract. Nanochitin is a nanoscale form of chitin—a polysaccharide found in the exoskeletons of crustaceans, insects, and some fungal cell walls—that is newly garnering significant attention in the pharmaceutical space. Its good properties, such as biocompatibility, biodegradability, and an easily adjustable surface, render it attractive for various medical and pharmaceutical applications. Nanochitin, from drug delivery systems and wound-care formulations to vaccine adjuvants and antimicrobial strategies, has demonstrated its strong potential in meeting diverse therapeutic needs. This review covers the background of nanochitin, including methods for its extraction and refining and its principal physicochemical and biological properties. It further discusses various hydrolysis and enzymatic approaches for the structural and functional characterization of nanochitin and highlights some pharmaceutical applications where this biopolymer has been studied. The review also addresses toxicity issues, regulatory matters, and challenges in large-scale industrial production. Finally, it underscores novel avenues of investigation and future opportunities, emphasizing the urgent requirement for standardized production methods, rigorous safety assessment, and interdisciplinary partnerships to maximize nanochitin’s potential in pharmaceutical research, demonstrating the importance of chitin in drug delivery.Ítem Microplastic pollution in Costa Rican marine ecosystems: Origins, ecotoxicological impacts, and mitigation strategies(Elsevier (Países Bajos), 2025) Zúñiga Umaña, Juan M.; Paniagua, Sergio A.; Corrales Brenes, Rebeca; Jose-Roberto, Vega-BaudritAbstract. Microplastics (MPs) and nanoplastics (NPs) have become ubiquitous worldwide, posing complex challenges for marine organisms, ecosystems, and human health. In Costa Rica alone, approximately 4000 tons of solid waste are generated daily, of which about 11 % is plastic. Nearly 600 million single-use plastic bottles are produced yearly, with ∼90 % not being collected. Consequently, reports of MPs in beaches, crustaceans, fishes, and bivalves are increasing on the Pacific and Caribbean coasts. Evidence suggests these plastic fragments can induce oxidative stress and inflammation in organisms, affect fundamental physiological processes (e.g., feeding, reproduction), and may even cross the blood–brain barrier. Recent policies in Costa Rica, including Law N°9786 (single-use plastics) and a proposed ban on MPs in cosmetics (Bill No. 23,694), mark progress. However, enforcement challenges remain—particularly given the country’s limited wastewater treatment coverage. This review discusses key sources of MPs (e.g., wastewater, synthetic fibers, tire wear), current sampling and characterization protocols, and ecotoxicological consequences for marine life and humans. We further analyze existing legislation, highlighting gaps and prospective solutions, and propose an integrated approach involving technological upgrades, biodegradable polymers, and microbial degradation strategies to mitigate plastic pollution.Ítem UAS Infrared Photogrammetry at the Poás Volcano Costa Rica; Digital Modeling of Volcanic Craters Used to Assist with Thermal Energy Release Estimations(DergiPark Akademik (Turquía), 2025) Godfrey, Ian; Sibaja Brenes, José Pablo; Avard, Geoffroy; Martínez Cruz, María; Meghraoui, KhadijaAbstract. Unmanned Aerial Systems frequently abbreviated UAS or drones are quickly emerging as an economical solution to compliment work in various sectors. UAS are being used successfully in analytical services, data collection and algorithm processing, advancements in modern aeronautical practices, data fusion, scientific synergy, UAS hardware solutions for information gathering, regulations for air space and requirements for remote pilots. Today drones are being successfully used in hazard assessment and making valued contributions to the scientific community such as the creation of the thermal 3-D digital model of the Poás Volcano National Park in Costa Rica. Drones were used in Costa Rica during the month of May of 2023 to assist Universidad Nacional with gathering data on the active crater and Laguna Caliente of the Poás Volcano National Park. The objective for using UAS at the summit of the volcano was to generate crater depth and other distance measurements, collect images used with georeferencing software to measure crater radius and estimating amounts of geological material in volume. UAS with IR sensors were used to monitor the dispersion of relative thermal energy release inside and around the active West Crater. The thermal energy release UAS survey was in cooperation with LAQAT-UNA Study of Volcanic Emissions and They´re Effects on the Local Communities.” UAS were used to try to monitor the temperature of the fumaroles individually from within the active crater. Drones were also deployed to gather videography of the degassing state observed from the aerial perspective from within the active crater of the Poás Volcano. All remote flights were completed using the SINAC Special Use UAS Research Permit – SINAC-ACC-PI-LC-037-2021.Ítem Deploying UAS Directly Inside the Active Crater of Turrialba for Photogrammetry Data Collection Designed for Active Volcano Monitoring(DergiPark Akademik (Turquía), 2025) Godfrey, Ian; Sibaja Brenes, José Pablo; Avard, Geoffroy; Martínez Cruz, María; Meghraoui, KhadijaAbstract. Modern UAS or drones are quickly advancing when it comes to the collection of high-resolution images which are georeferenced and can be used to create a high resolution 3-D model of complex topography. Researchers in the field are making quick progress with new algorithms and analytical applications. These drones are being used in the field of volcanology in quite a useful manner as active volcano craters are one of the more challenging and complex areas to access. UAS have now assisted several departments of Universidad Nacional with data collection, analytics and optimization practices. In May of 2023 with the assistance of the Atmospheric Chemistry Laboratory of Universidad Nacional LAQAT-UNA and the Volcanic and Seismic Observatory of Costa Rica OVSICORI-UNA showed that our efforts using UAS at active volcanoes was greatly beneficial and the collective efforts proved the usefulness of deploying UAS around active degassing volcanoes such as the Turrialba Volcano in Costa Rica. Researchers in several departments at Universidad Nacional are keen on collaborating with others in international institutions for data fusion and synergy, to work together on gathering information on how to create better UAS hardware and payload components, and to cooperate for a better understanding of user needs, regulations and requirements for the safe operation of UAS. UAS allow for collection of accurate images which keep the researchers and remote pilots safe and out of the danger zone. UAS assist with the rapid accumulation of data, they can be pre- programmed for a specific type of UAS flight mission designed for a certain objective of gathering images for complex terrain or topography. The system can be used around active volcano craters, it can monitor mountains and cliffs subject to cracking, erosion and rock falls. Different extreme and complex environments can be documented and digitalized using this same method such as glacier zones and other sophisticated regions with difficult to access areas. All remote flights were using the SINAC Special Use UAS Research Permit – SINAC-ACC-PI-LC-037-2021Ítem Comparación de dos metodologías de cálculo de emisiones de gases efecto invernadero para vehículos en Costa Rica, 2014(Tecnológico de Costa Rica (TEC) (Costa Rica), 2024) Picado-Valenzuela, Priscila; Rodríguez- Yánez, Javier E.; Sibaja-Brenes, José PabloResumen. Contar con métodos confiables para estimar las emisiones antropogénicas de Gases de Efecto Invernadero (GEI) es de vital importancia para diseñar estrategias eficientes para mitigar los efectos del cambio climático. Uno de estos métodos es el software MOVES (Motor Vehicle Emission Simulator) diseñado por la Agencia de Protección Ambiental de los Estados Unidos (US-EPA). Otra metodología es la implementada por el Instituto Meteorológico Nacional (IMN) de Costa Rica, la cual se basa en las directrices del Panel Intergubernamental de Cambio Climático (IPCC). El objetivo de este trabajo es determinar la factibilidad de utilizar MOVES en el contexto costarricense para la obtención de factores locales que mejoren las estimaciones de emisiones de GEI para fuentes móviles vehiculares en Costa Rica en el 2014. Para esto se evaluaron dos escenarios de emisiones estimadas de GEI calculados mediante el software de modelado MOVES y la metodología de cálculo implementada por el IMN. Para esto se recopiló información de diferentes fuentes oficiales para suplir de datos a ambas metodologías y realizar el análisis. Asimismo, se realizó una comparación cuantitativa con una escala Likert para determinar la confiabilidad de los dos métodos. Como resultados se determinó que MOVES calcula valores de emisión de GEI más altos que la metodología del IMN. Relacionado con esto, el análisis con las categorías Likert demostró que la confiabilidad de los datos de la metodología MOVES para Costa Rica es menor que los utilizados por el IMN. En conclusión la metodología de cálculo de emisiones de GEI por MOVES y por el IMN brindan un rango superior e inferior al cálculo de emisiones de GEI. Asimismo, ambas metodologías plantean aproximaciones complementarias al estudio de las emisiones de GEI.Ítem Evaluación del riesgo en la salud del personal del Parque Nacional Volcán Poás, Costa Rica, por exposición a los gases SO2 y H2S(Universidad Nacional (Costa Rica), 2024) Morales-Alpízar, José David; Sibaja-Brenes, José Pablo; Mora-Barrantes, José Carlos; Martínez-Cruz, María; Borbón-Alpízar, Henry; Retana-Díaz, Alexa; Alfaro-Solís, RosaResumen. [Objetivo] Verificar el cumplimiento de los niveles de exposición a SO2 y H2S, de los guardaparques del Parque Nacional Volcán Poás, tomando como referencia la norma internacional OSHA. [Metodología] Se estudió la concentración del SO2 desde setiembre 2018, hasta diciembre 2019 y para el H2S de febrero 2019, hasta diciembre 2019, haciendo uso de equipos de detección portátiles MultiRae. Los puntos de muestreo se colocaron en la casa de guardaparques, la caseta de entrada, el centro de visitantes y el mirador. El nivel de riesgo químico se determinó considerando: la salud de los trabajadores, el tiempo de exposición, el equipo de seguridad, las capacitaciones y los valores de TWA y STEL obtenidos. [Resultados] El valor más alto de la concentración de SO2 fue de 16,0 ppm, se registró en el centro de visitantes, y para el de H2S fue de 45 ppm (casa de guardaparques). La concentración promedio de los gases estuvo cercana al límite de detección para ambos gases, sugiriendo que los gases, en general, no se dirigen hacia las zonas de visitación. Ningún puesto de medición superó los 2 ppm para el SO2 en 8 horas (TWA). Sin embargo, en el centro de visitantes y en el mirador para visitantes, se superó los 5 ppm de SO2 en 15 minutos (STEL), con concentraciones de 10,1 ppm y 7,4 ppm, respectivamente. [Conclusiones] Se obtuvieron niveles bajos de riesgo químico, para ambos gases, en los puntos muestreados, a excepción del punto del centro de visitantes, donde el nivel de riesgo fue medio.Ítem Validación de un método de cromatografía líquida (HPLC-UV/Vis) para la cuantificación de aldehídos en agua de lluvia y aire(Universidad Nacional (Costa Rica), 2024) Araya Araya, Melissa; Sibaja Brenes, José Pablo; Soto-Fallas, Roy; Mora-Barrantes, Jose Carlos; Alfaro Solís, Rosa; Borbón-Alpízar, Henry; Valdés González, JuanResumen. Los aldehídos son compuestos presentes en la atmósfera que se forman por la degradación fotoquímica de otros compuestos orgánicos en la tropósfera, estos pueden ser emitidos por fuentes naturales o antropogénicas. [Objetivo] En el presente trabajo se implementó un método analítico para la cuantificación de muestras de aldehídos en matrices como aire y agua de lluvia. [Metodología] El muestreo y el análisis de los aldehídos utilizó la metodología TO-11 de la Agencia de Protección Ambiental de los Estados Unidos (EPA). El muestreo se realizó mediante el uso de cartuchos de adsorción recubiertos con una disolución de 2,4-DNFH, formando una hidrazona con los aldehídos presentes en el agua de lluvia y en el aire. Estos fueron analizados mediante un cromatógrafo de líquido acoplado a un detector UV-Visible (HPLC-UV/Vis). Para la validación de la técnica de análisis y la calidad analítica de los resultados se determinaron: linealidad, sensibilidad, límites de cuantificación, límites de detección, repetibilidad, reproducibilidad y porcentaje de recuperación. En el caso de la repetibilidad, se utilizó la comparación del coeficiente de variación de Horwitz con los porcentajes de desviación estándar relativo (% DER) de las muestras. [Resultados] Los límites de detección obtenidos oscilan entre 0,18 μg/m3 para el acetaldehído y 3,20 μg/m3 en el caso de la acroleína, mientras que los límites de cuantificación están entre 0,62 μg/m3 para el acetaldehído y 4,70 μg/m3 para el heptanal; datos que garantizan la calidad analítica del método. [Conclusiones] En general, el método de análisis para los aldehídos mostró una buena correlación lineal, con valores de R2 igual o mayores a 0,9991 para cada curva de calibración, y valores de porcentajes de desvío relativo menores al 2,25 %, lo cual indica una buena precisión en el análisis.Ítem Phytochemical Profiling of Clusia valerioi (Standl.) Floral Resin and Its Correlation with the Chemical Composition of Propolis from Southern Costa Rica(Universidad Nacional de Misiones (Argentina), 2025) Segura-Víquez, Andrea; Soto-Fallas, Roy M.; Borbón-Alpízar, Henry; Umaña-Rojas, Eduardo; Zamora-Fallas, Gabriel; Sánchez-Chaves, Luis; Fallas-Matamoros, Natalia; Montenegro-Hidalgo, Víctor; Alfaro-Alarcón, Alejandro; Guevara-González, Mariana; Romero-Vega, Luis; Loaiza-Montoya, Randall; Picado-Canales, Natalin; Barrantes-Murillo, ErikaAbstract. Propolis are resinous byproducts produced by bees, known for their wide range of bioactive properties. The chemical composition of propolis is closely linked to the botanical environment surrounding the hive. Clusia valerioi (Standl.), a plant species endemic to Costa Rica, is commonly found in the country's southern region and produces floral resins that are collected by bees for propolis production. This ecological relationship suggests that chemical traceability between C. valerioi floral resins and propolis produced in nearby apiaries is feasible. In this study, ethanolic extracts from propolis samples collected at eight apiaries, resin loads transported by forager bees, and floral resin samples from C. valerioi at four sites near two of these apiaries were analyzed using high-performance thin-layer chromatography (HPTLC). The analysis revealed three chemical markers—referred to as compounds A, B, and C—that support the traceability of chemical constituents from floral resin to propolis. Compound A was identified as a terpene derivative, while compound C was determined to be a flavonoid derivative (specifically a flavonol or flavanone). Compound B was isolated and identified as a polyprenylated polycyclic benzophenone, and was conclusively characterized as nemorosone based on proton (¹H-NMR) and carbon-13 (¹³C-NMR) nuclear magnetic resonance spectra.Ítem Producción de plástico biodegradable a base de almidón de yuca mediante un proceso termomecánico(Universidad de Costa Rica (Costa Rica), 2025) Moya Alvarado, Guillermo; Miranda Morales, Bárbara; Jiménez Villalta, GuillermoResumen. El presente trabajo pretende elaborar un polímero termoplástico a base de almidón (TPS) extraído de una variedad de yuca, mediante un procesamiento termomecánico en un mezclador interno de polímeros. Se examinaron preliminarmente tres formulaciones para establecer una formulación base y se escogió el alcohol polivinílico (PVOH) para reforzar el TPS. Asimismo, se realizó un estudio estadístico de las condiciones de procesamiento, las cuales se establecieron en una temperatura de 110 °C, una velocidad de 75 rpm (1,25 Hz) y un tiempo de mezcla de 6 min. Finalmente, mediante un ajuste de los porcentajes relativos de los componentes, se llegó a obtener un material con una resistencia en tensión de (15,4 ± 0,9) MPa y una elongación de (44 ± 11) %. Por medio de una prueba de envejecimiento, se observó que las propiedades del TPS se estabilizaron a los 15 días de su elaboración. Además, a través de un estudio de la biodegradabilidad, se observó una reducción en la masa del plástico del (98,5 ± 0,3) %, luego de 22 días de enterrado. Bajo condiciones controladas, el material presenta propiedades mecánicas adecuadas para ser usado en aplicaciones cotidianas; sin embargo, es necesario subsanar su sensibilidad a la humedad ambiental, ya que esta influye de manera importante en dichas propiedades mecánicas.Ítem From mountains to cities: a novel isotope hydrological assessment of a tropical water distribution system(Taylor & Francis Group (Reino Unido), 2020) Sánchez-Murillo, Ricardo; Esquivel-Hernández, Germain; Birkel, Christian; Ortega, Lucia; Sánchez-Guerrero, Michael; Rojas-Jiménez, Luis Daniel; Vargas-Víquez, José; Castro-Chacón, LauraAbstract. Water use by anthropogenic activities in the face of climate change invokes a better understanding of headwater sources and lowland urban water allocations. Here, we constrained a Bayesian mixing model with stable isotope data (2018–2019) in rainfall (N = 704), spring water (N = 96), and surface water (N = 94) with seasonal isotope sampling (wet and dry seasons) of an urban aqueduct (N = 215) in the Central Valley of Costa Rica. Low δ18O rainfall compositions corresponded to the western boundary of the study area, whereas high values were reported to the northeastern limit, reflecting the influence of moisture transport from the Caribbean domain coupled with strong orographic effects over the Pacific slope. The latter is well-depicted in the relative rainfall contributions (west versus east) in two headwater systems: (a) spring (68.7 ± 3.4 %, west domain) and (b) stream (55.8 ± 3.9 %, east domain). The aqueduct exhibited a spatial predominance of spring water and surface water during a normal wet season (78.7 %), whereas deep groundwater and spring water were fundamental sources for the aqueduct in the dry season (69.4 %). Our tracer-based methodology can help improve aqueduct management practices in changing climate, including optimal water allocation and reduced evaporative losses in the dry season.Ítem Nitrate isotopes (δ15N, δ18O) in precipitation: best practices from an international coordinated research project(Taylor & Francis Group (Reino Unido), 2023) Esquivel-Hernández, Germain; Matiatos, Ioannis; Sánchez-Murillo, Ricardo; Vystavna, Yuliya; Balestrini, Raffaella; Wells, Naomi S.; Monteiro, Lucilena Rebelo; Chantara, Somporn; Walters, Wendell; Wassenaar, Leonard I.Abstract. Stable isotope ratios of nitrogen and oxygen (15N/14N and 18O/16O) of nitrate (NO3–) are excellent tracers for developing systematic understanding of sources, conversions, and deposition of reactive atmospheric nitrogen (Nr) in the environment. Despite recent analytical advances, standardized sampling of NO3–) isotopes in precipitation is still lacking. To advance atmospheric studies on Nr species, we propose best-practice guidelines for accurate and precise sampling and analysis of NO3– isotopes in precipitation based on the experience obtained from an international research project coordinated by the International Atomic Energy Agency (IAEA). The precipitation sampling and preservation strategies yielded a good agreement between the NO3– concentrations measured at the laboratories of 16 countries and at the IAEA. Compared to conventional methods (e.g., bacterial denitrification), we confirmed the accurate performance of the lower cost Ti(III) reduction method for isotope analyses (15N and 18O) of NO3– in precipitation samples. These isotopic data depict different origins and oxidation pathways of inorganic nitrogen. This work emphasized the capability of NO3– isotopes to assess the origin and atmospheric oxidation of Nr and outlined a pathway to improve laboratory capability and expertise at a global scale. The incorporation of other isotopes like 17O in Nr is recommended in future studies.Ítem Stable isotope tempestology of tropical cyclones across the North Atlantic and Eastern Pacific Ocean basins(The New York Academy of Sciences (Estados Unidos), 2025) Sanchez-Murillo, Ricardo; Herrera, Dimitris A.; Farrick, Kegan K.; Esquivel-Hernández, Germain; Sánchez-Gutiérrez, Rolando; Barberena-Moncada, Javier; Guatemala-Herrera, Jorge; Flores-Meza, Yelba; Cerón-Pineda, Roberto; Gil-Urrutia, Laura; Cardona-Hernández, Jorge; Peña-Paz, Tania; Hernández-Ortiz, Junior O.; Harrison-Smith, Wendy; Marshall, Geoffrey; Persoiu, Aurel; Pérez-Quezadas, Juan; Mejía-González, Miguel; González-Hita, Luis; Barrera de Calderón, Marcia; García-Moya, Alejandro; Hernández, Debora; Welsh, Kristen; Price, Rene M.; Riveros-Iregui, Diego; Voarintsoa, Ny Riavo; Bregy, Joshua C.; Sánchez-Llull, Minerva; Alonso-Hernández, Carlos; Santos-García, Saúl; Durán-Quesada, Ana M.; Birkel, Christian; Boll, Jan; Cobb, Kim M.; Obando-Amador, Adrián F.; Vargas-Azofeifa, Ingrid M.; Tetzlaff, Doerthe; Soulsby, Chris; Dee, SylviaAbstract. Tropical cyclones (TCs) are one of the major natural hazards to island and coastal communities and ecosystems. However, isotopic compositions of TC-derived precipitation (P) in surface water (SW) and groundwater (GW) reservoirs are still lacking. We tested the three main assumptions of the isotope storm “spike” hypothesis (sudden spikes in isotopic ratios). Our database covers 40 TCs and is divided into recent (N = 778; 2012–2023) and archived (N = 236; 1984–1995) rainfall isotope observations and SW/GW isotope monitoring (N = 6013; 2014–2023). Seasonal rainfall contribution from TCs ranged from less than 1% to over 54% (4% on average) between 1984 and 2023. Mean δ18O compositions across TCs domains were significantly lower than the regional (noncyclonic) δ18O mean (−5.24 ± 4.27‰): maritime (−6.29 ± 3.28‰), coastal (−7.78 ± 4.28‰), and inland (−9.80 ± 5.18‰) values. Coastal and maritime TC convection resulted in large rainfall amounts with high isotope compositions. This could bias past climate reconstructions toward unrealistic drier conditions. Significant δ18O and d-excess differences were found between storm intensities. P/SW and P/GW isotope ratios revealed the rapid propagation of TC excursions in freshwater systems. Our findings highlight the potential of TC isotope observations for diagnosing intensity and frequency in paleoproxies beyond idealized TC models.Ítem Bovine Serum Albumin-Based Nanoparticles: Preparation, Characterization, and Antioxidant Activity Enhancement of Three Main Curcuminoids from Curcuma longa(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2022) Araya Sibaja, Andrea Mariela; Wilhelm, Krissia; Quirós, Maria Isabel; Vargas-Huertas, Felipe; Jose-Roberto, Vega-Baudrit; Navarro-Hoyos, MirthaAbstract. Bovine Serum Albumin (BSA) lipid hybrid nanoparticles are part of the new solutions to overcome low bioavailability of poor solubility drugs such as curcuminoids, which possess multiple biological advantages; however, they are counterbalanced by its short biological half-life. In this line, we prepared the three main curcuminoids: curcumin (CUR), desmethoxycurcumin (DMC), and bisdemethoxycurcumin (BDM)-loaded BSA nanoparticles. The three formulations were characterized by the average size, size distribution, crystallinity, weight loss, drug release, kinetic mechanism, and antioxidant activity. The developed method produced CUR-, DMC-, and BDM-loaded BSA nanoparticles with a size average of 15.83 0.18, 17.29 3.34, and 15.14 0.14 nm for CUR, MC, and BDM loaded BSA, respectively. FT-IR analysis confirmed the encapsulation, and TEM images showed their spherical shape. The three formulations achieved encapsulation efficiency upper to 96% and an exhibited significantly increased release from the nanoparticle compared to free compounds in water. The antioxidant activity was enhanced as well, in agreement with the improvement in water release, obtaining IC50 values of 9.28, 11.70, and 15.19 g/mL for CUR, DMC, and BDM loaded BSA nanoparticles, respectively, while free curcuminoids exhibited considerably lower antioxidant values in aqueous solution. Hence, this study shows promises for such hybrid systems, which have been ignored so far, regarding proper encapsulation, protection, and delivery of curcuminoids for the development of functional foods and pharmaceuticals.Ítem Tracer hydrology of the data-scarce and heterogeneous Central American Isthmus(John Wiley (Estados Unidos), 2020) Sánchez-Murillo, Ricardo; Esquivel-Hernández, Germain; Corrales-Salazar, José L.; Castro-Chacón, Laura; Durán-Quesada, Ana M.; Guerrero-Hernández, Manuel; Delgado, Valeria; Barberena, Javier; Montenegro-Rayo, Katia; Calderón, Heyddy; Chevez, Carlos; Peña-Paz, Tania; García-Santos, Saúl; Ortiz-Roque, Pedro; Alvarado-Callejas, Yaneth; Benegas, Laura; Hernández-Antonio, Antonio; Matamoros-Ortega, Marcela; Ortega, Lucia; Terzer-Wassmuth, StefanAbstract. Numerous socio-economic activities depend on the seasonal rainfall and groundwater recharge cycle across the Central American Isthmus. Population growth and unregulated land use changes resulted in extensive surface water pollution and a large dependency on groundwater resources. This work combines stable isotope variations in rainfall, surface water, and groundwater of Costa Rica, Nicaragua, El Salvador, and Honduras to develop a regionalized rainfall isoscape, isotopic lapse rates, spatial–temporal isotopic variations, and air mass back trajectories determining potential mean recharge elevations, moisture circulation patterns, and surface water groundwater interactions. Intra-seasonal rainfall modes resulted in two isotopically depleted incursions (W-shaped isotopic pattern) during the wet season and two enriched pulses during the mid-summer drought and the months of the strongest trade winds. Notable isotopic sub-cloud fractionation and near-surface secondary evaporation were identified as common denominators within the Central American Dry Corridor. Groundwater and surface water isotope ratios depicted the strong orographic separation into the Caribbean and Pacific domains, mainly induced by the governing moisture transport from the Caribbean Sea, complex rainfall producing systems across the N-S mountain range, and the subsequent mixing with local evapotranspiration, and, to a lesser degree, the eastern Pacific Ocean fluxes. Groundwater recharge was characterized by (a) depleted recharge in highland areas (72.3%), (b) rapid recharge via preferential flow paths (13.1%), and enriched recharge due to near-surface secondary fractionation (14.6%). Median recharge elevation ranged from 1,104 to 1,979 m a.s.l. These results are intended to enhance forest conservation practices, inform water protection regulations, and facilitate water security and sustainability planning in the Central American Isthmus.Ítem Effect of physalins on the modulation of NF-kB and its possible implications for glucose homeostasis(AkiNik Publications (India), 2017) Pequeno, Andréia; Miranda, Yendry; Rodríguez, Gerardo; Valverde, Víctor; Álvarez, Luis; Da Silva, Tania; Da Silva Junior, ValdemiroAbstract. Physalins are steroidal lactone constituents of physalis and other closely related genera that belong to the Solanaceae family. These secondary metabolites have attracted much attention in recent years due to their various biological effects: they are anticarcinogenic, anti-inflammatory, immunomodulating, antibacterial and anti-diabetic. Researchers have shown that physalins are potential inhibitors of NF-kB activation via inhibition of phosphorylation and degradation of IκBα. Moreover, studies performed in a variety of cell and animal-based experimental systems suggest that NF-kB activation is a key event in the early pathobiology of diabetes. Therefore, these results indicate that physalins can be considered as a novel class of NF-kB inhibitors, which are promising as innovative anti-inflammatory agents for the treatment of various inflammatory disorders and diabetes. This review discusses current knowledge about physalins, and evidence of its effects on the modulation of NF-kB, as well as its implications for glucose homeostasis and the prevention and treatment of diabetes.Ítem Influencia de la edad en el contenido de fenoles y ligninas en Gmelina arborea (Lamiaceae)(Universidad de Costa Rica (Costa Rica), 2024) Azofeifa, José; Álvarez Valverde, Víctor; Olivares Madriz, Ashly; Pineda Cascante, Mariana; Campos Salas, Daniela; Hine, AnaResumen. Introducción: La melina (Gmelina arborea), es una especie de gran interés por su madera y propiedades medicinales. En Costa Rica, existen clones genéticamente superiores que se propagan sin el conocimiento de la edad ontogénica y fisiológica de los materiales. Objetivo: Evaluar la relación del contenido de fenoles y ligninas en hojas, peciolos, tallos y raíces de plantas con diferentes edades. Métodos: Los contenidos de fenoles y ligninas totales se determinaron mediante el método colorimétrico de Folin-Ciocalteu y el método de extracción alcalina, respectivamente. Para la investigación se eligieron plantas in vitro “año cero” y árboles de año y medio, cuatro, siete y 20 años. El muestreo se realizó en marzo y abril del 2021. Resultados: Se demostró que todas las partes de la planta analizadas contienen compuestos fenólicos y ligninas, independientemente de su edad. No hubo una correlación positiva entre la edad con el contenido de fenoles y ligninas para ninguna condición de desarrollo, pues los valores más altos no se obtuvieron en los árboles más longevos. Los extractos de hojas de las plantas in vitro y los árboles de siete años mostraron, respectivamente, los contenidos más altos de fenoles y ligninas para todas las condiciones (P < 0.05). Los valores promedio más bajos de compuestos fenólicos para todas las condiciones se obtuvieron en los árboles de cuatro años. Respecto a las ligninas, el contenido más bajo se presentó en las raíces más longevas, aunque la tendencia no se mantuvo para el resto de las partes de la planta. Conclusiones: La investigación muestra los primeros resultados del contenido de compuestos fenólicos y ligninas presentes en diferentes tejidos de una especie forestal de edades diferentes. Por lo tanto, son los primeros valores de referencia acerca del compromiso bioquímico para la síntesis fenólica según la edad y el estado de desarrollo específico de una planta leñosa.Ítem Experiencia de aprendizaje en la transmisión de conocimientos teóricos y prácticos con aplicación de una evaluación formativa en laboratorios de química(Universidad del Valparaíso (Chile), 2017) Álvarez Valverde, Víctor; Hernández Elizondo, PriscillaResumen. En los laboratorios de Química General, Química Orgánica y Bioquímica, se ha dado un estricto énfasis a la verificación del conocimiento adquirido por los estudiantes, a través de métodos tales como la preparación previa, −tanto de alumnos, como de docentes−; realización de pruebas cortas, discusión de la materia antes de iniciar el laboratorio y, en forma grupal, al finalizar la práctica. Asimismo, los estudiantes deben elaborar un informe en el que expliquen, con apoyo del material bibliográfico actualizado, su interpretación de lo ocurrido al culminar la experiencia. Estas acciones despiertan su interés a lo largo del semestre, lo cual se traduce en una elevada promoción.Ítem Phytochemical characterization and antioxidant profile of Sechium edule (Jacq) Swartz Cucurbitaceae ) varieties grown in Costa Rica(GarVal Editorial Ltda (Chile), 2018) Parra, Jonathan; Hernández, Priscilla; Ocampo-Maroto, Fernando; Álvarez-Valverde, Víctor; Carvajal-Miranda, Yendry; Rodríguez-Rodríguez, Gerardo; Herrera, CristinaAbstract. Context: The Sechium edule fruit is grown and consumed because of their nutritional values in different countries of Latin America. Costa Rica is one of the most important producers and exporters. It is consumed as an antioxidant because its flavonoid content suggests such activity; however, the selection of varieties to crop does not involve the phytochemical profile of them. Aims: To characterize the phytochemical and antioxidant profile of the S. edule varieties grown in Costa Rica. Methods: The in vitro radical scavenging activity of different S. edule extracts were measured using DPPH and ORAC assays, as well as their inhibition of lipid peroxidation in rat liver and their redox potential by cyclic voltammetry. Flavonoids glycosides were isolated by HPLC and their structures were determined by NMR. Results: The S. edule varieties grown in Costa Rica showed a good radical scavenging activity and inhibition of lipid peroxidation; there were significant differences between varieties. In addition, the redox potential determined by electrochemical methods suggested the presence of flavonoids, which was confirmed by the isolation of apigenin 7-O-rutinoside and luteolin 7-O-rutinoside. Conclusions: The antioxidant potential of varieties of S. edule grown in Costa Rica was confirmed, identifying the 845 variety as the best antioxidant profile.