15 research outputs found
Nanopartículas poliméricas impresas molecularmente para su aplicación en Elisa : anticuerpos sintéticos.
No full textTesis presentada para optar al grado de Doctor en Ciencias con mención en Química.El ensayo inmunoabsorbente ligado a enzimas (ELISA) es el inmunoensayo más conocido y utilizado en la detección de una gran variedad de analitos mediante el uso de anticuerpos. No obstante, presenta inconvenientes asociados al uso de anticuerpos y enzimas. Lo anterior, debido a que la producción de anticuerpos es costosa, requiere demasiado tiempo e involucra el uso de animales. Para resolver estos inconvenientes, surge como propuesta el reemplazo de los anticuerpos utilizados en inmunoensayos por polímeros de impresión molecular (MIPs), los cuales actúan como receptores biomiméticos. Estos polímeros son obtenidos en presencia de la molécula objetivo (o plantilla), por lo que poseen alta afinidad y selectividad hacia esta molécula, además su obtención es fácil y de bajo costo. Por lo anterior, el objetivo de este trabajo fue obtener nanoMIPs específicos para Microcistina-LR (MC-LR), benzoilecgonina y pepsina, y demostrar la idoneidad y especificidad en su aplicación como anticuerpos sintéticos en ELISA (pseudo-ELISA). Para ello, se sintetizaron nanoMIPs mediante la novedosa síntesis en fase sólida, y se desarrollaron pseudo-ELISAs para la detección de MC-LR en agua y Cocaína y sus metabolitos en suero sanguíneo, además se hicieron modificaciones en la superficie de las nanoMIPs obtenidas, con el fin de aumentar la selectividad hacia el analito cuando se analizan muestran complejas como suero sanguíneo. Los resultados obtenidos en esta primera parte de la tesis demostraron que las nanoMIPs obtenidas mediante síntesis en fase sólida poseían mayor sensibilidad y estabilidad que los anticuerpos tradicionalmente utilizados en ELISA, ya que presentaron límites de detección inferiores a los reportados por anticuerpos en los kits comerciales. En la segunda parte de ésta tesis, se trabajó en el desarrollo de un ensayo totalmente abiótico alternativo a ELISA, denominado ensayo magnético competitivo, en este ensayo se reemplazaron tanto los anticuerpos como las enzimas por nanoMIPs fluorescentes (F-nanoMIPs) y se utilizó pepsina como plantilla modelo en los análisis. Como resultado, de esta modificación, fue posible el desarrollo de un nuevo método análogo al ELISA convencional, pero libre de biomoléculas, con menos pasos en el protocolo, más económico y con igual selectividad hacia la molécula objetivo. Por lo anterior, se concluye que la incorporación de nanoMIPs y F-nanoMIPs en ELISA son una prometedora alternativa para el desarrollo de nuevas metodologías analíticas capaces de detectar con alta selectividad cualquier analito de interés.Facultad de Ciencias QuímicasConcepció
El desarrollo de habilidades de comprensión en los estudiantes de las EPEF para la Universidad
No full textEste trabajo engloba una preocupación para la educación, en sentido general, en cuanto a lo relacionado con el proceso de comprensión de la lectura. Es el resultado de una valoración de las investigaciones realizadas al respecto por lingüistas, psicólogos y estudiosos de la comunicación, quienes revelan aspectos fundamentales de las operaciones que realiza el lector durante la atribución de significados y sentidos a textos de diferentes tipologías. Asimismo, se reflejan problemas afines con la enseñanza- aprendizaje de la comprensión de la lectura y se pone de relieve la necesidad de desarrollar dicho proceso, se pudieron determinar las principales carencias de los estudiantes y el poco aprovechamiento de las potencialidades que ofrece el tratamiento del texto para el desarrollo de una cultura general e integral, dada su naturaleza interdisciplinaria.
Se brinda una actividad como ejemplo, con carácter integrador, transformador, contextual y flexible que se orienta hacia el perfeccionamiento del proceso pedagógico y al desarrollo cultural que debe producirse en el estudiante como vía que posibilita del enriquecimiento humano a partir de un diagnóstico psicopedagógico integral y la sistematización de las experiencias directas y naturales acumuladas por la autora en su aplicación a lo largo de la práctica educativa. Esta experiencia tributa a la formación de una cultura general e integral, al desarrollo de estrategias cognitivas, metacognitivas y comunicativas en los estudiantes desde un enfoque cognitivo, comunicativo y sociocultural.
Palabras clave: habilidades, comprensión, lectura, aprendizaje, estrategia, niveles
The development of comprehension skills in EPEF students for the University
Abstract
This work encompasses a concern for education, in a general sense, in terms of the process of reading comprehension. It is the result of an assessment of the research carried out in this regard by linguists, psychologists and communication scholars, who reveal fundamental aspects of the operations carried out by the reader during the attribution of meanings and meanings to texts of different types. Likewise, problems related to the teaching-learning of reading comprehension are reflected and the need to develop this process is highlighted, it was possible to determine the main shortcomings of the students and the little use of the potentialities offered by the treatment of the text for the development of a general and comprehensive culture, given its interdisciplinary nature.
An activity is provided as an example, with an integrative, transformative, contextual and flexible character that is oriented towards the improvement of the pedagogical process and the cultural development that must occur in the student as a way that enables human enrichment based on a comprehensive psychopedagogical diagnosis and the systematization of the direct and natural experiences accumulated by the author in their application throughout the educational practice. This experience contributes to the formation of a general and comprehensive culture, to the development of cognitive, metacognitive and communicative strategies in students from a cognitive, communicative and sociocultural approach.
Keyword: skills, comprehension, reading, learning, strategy, levels
Recibido julio 2019 Aprobado diciembre 2019
 
Molecularly Imprinted Polymers for the Selective Extraction of Bisphenol A and Progesterone from Aqueous Media
No full textThis paper describes the development of a novel sorbent for selective extraction of endocrine disruptors (EDs) from aqueous media. The main goal was to obtain sufficient molecularly imprinted polymers (MIPs) for selective detection, preconcentration, and extraction of EDs such as bisphenol A (BPA) and progesterone (PG). Series of MIPs and their analogues, non-molecularly imprinted polymers (NIPs), were synthesised following a non-covalent imprinting strategy based on radical polymerisation. Sets of synthesis were performed in order to optimise variables of the polymerisation including solvent, cross-linker, and template ratio. The retention capacity of MIPs was determined using HPLC in the range of 33.3% to 96.6% and 32.5% to 96% for BPA and PG, respectively. The adsorption mechanism was studied by isothermal and kinetic assays. The kinetic analysis showed a high retention capacity within 15 min of contact. The polymer yield was obtained in the range of 30% to 100%. Additionally, there was no significant cross-reactivity observed upon testing MIPs with structural analogues and other endocrine disruptors instead of target molecules. The results also revealed the high importance of different concentrations of cross-linker and solvent during the polymerisation. Firstly, the pre-organisation of complementary functional groups, which were present in the polymerisation mixture, and secondly, selective cavity formation for target molecules
Molecularly Imprinted Nanoparticle-Based Assay for Tetracycline Determination at Subnanomolar Levels
No full textAntibiotic determination at low concentrations is a critical challenge to ensure water, food, and environmental safety. This work reports the application of molecularly imprinted nanoparticles (MINs) as synthetic antibodies in a microplate assay for tetracycline (TC) determination at subnanomolar levels. MINs with hydrodynamic radii ranging from 200 to 300 nm were synthesized via solid-phase imprinting on magnetic nanoparticles using lymecycline (LMC) as an auxiliary template. MINs immobilized onto polystyrene microplates exhibited a selective binding of the conjugate between LMC and horseradish peroxidase (HRP), yielding analytical responses up to fourfold higher than those observed in blank wells. MINs saturated with LMC-HPR showed the quantitative displacement of the conjugate upon incubation with LMC or TC, yielding concentration-proportional responses from 0.001 to 100 nmol L-1. For LMC, we obtained limits of detection (LOD) between 0.018 and 0.020 nmol L-1 and limits of quantification (LOQ) from 0.054 to 0.061 nmol L-1. For TC, the LOD values ranged between 0.001 and 0.006 nmol L-1, with LOQ values of 0.004-0.019 nmol L-1. Within the studied concentration range, the analytical responses of MINs were two to five times higher than those obtained from nonimprinted materials or blank controls. These findings support the performance of MINs as antibody mimetics with high recognition capacity, relatively low production costs, and robust analytical applications
Laccase-mediated polymerization of tannins from a pine bark extract: Toward an eco-friendly valorization of forest wastes
No full textIndexación: ScopusThe valorization of tannins from forest by-products is a major opportunity for the sustainable development of the forestry industry. Herein we report the laccase-mediated polymerization of tannins obtained from an aqueous pine bark extract. The reaction was conducted under an oxygen atmosphere at 50°C for 60 min and followed by UV–Vis, fluorescence intensity, phenol content, and viscosity measurements. An insoluble polymer was obtained after 45 min, which was attributed to coupling reactions triggered by phenoxyl radicals within the tannins mixture. The polymer showed a marked increase in thermal stability compared with the precursor pine bark extract, with a total mass loss of less than 12% at temperatures up to 500°C, suggesting potential practical applications in flame retardant materials. Additionally, the polymer showed an 85% DPPH activity and a 60% attenuation of singlet oxygen release upon light irradiation, which supports antioxidant and photoprotective properties for the prepared material. To the best of our knowledge, this is the first report to describe the formation of an insoluble polymer by direct enzymatic reaction of an aqueous tannin extract. In this case, soluble tannins are the sole reactants used to produce a promising versatile material for forest waste valorization. © 2024 Wiley Periodicals LLC.https://onlinelibrary-wiley-com.recursosbiblioteca.unab.cl/doi/10.1002/app.55437Agencia Nacional de Investigación y Desarrollo, Grant/Award Numbers: 3200601, 1211450; Vicerrectoría de Investigación y Desarrollo, UdeC, Grant/Award Number: 2023000795INI; Portuguese Foundation for Science and Technology, Grant/Award Number: UIDB/04469/2020.
ACKNOWLEDGMENTS The authors would like to thank the Fondecyt Postdoctoral 3200601, Fondecyt Regular 1211450, VRID N 2023000795INI, and UIDB/04469/2020 projects for their financial support.S
Laccase-mediated polymerization of tannins from a pine bark extract: toward an eco-friendly valorization of forest wastes
No full textThe valorization of tannins from forest by-products is a major opportunity for the sustainable development of the forestry industry. Herein we report the laccase-mediated polymerization of tannins obtained from an aqueous pine bark extract. The reaction was conducted under an oxygen atmosphere at 50°C for 60min and followed by UVVis, fluorescence intensity, phenol content, and viscosity measurements. An insoluble polymer was obtained after 45min, which was attributed to coupling reactions triggered by phenoxyl radicals within the tannins mixture. The polymer showed a marked increase in thermal stability compared with the precursor pine bark extract, with a total mass loss of less than 12\% at temperatures up to 500°C, suggesting potential practical applications in flame retardant materials. Additionally, the polymer showed an 85\% DPPH activity and a 60\% attenuation of singlet oxygen release upon light irradiation, which supports antioxidant and photoprotective properties for the prepared material. To the best of our knowledge, this is the first report to describe the formation of an insoluble polymer by direct enzymatic reaction of an aqueous tannin extract. In this case, soluble tannins are the sole reactants used to produce a promising versatile material for forest waste valorization.The authors would like to thank the Fondecyt Postdoctoral 3200601, Fondecyt Regular 1211450, VRID
Nº 2023000795INI, and UIDB/04469/2020 projects for their financial support.info:eu-repo/semantics/publishedVersio
Propuesta de intervención basada en pedagogía crítica para generar cultura de paz en el aula de clase
No full textEsta investigación tiene como propósito contribuir a la cultura de paz y no violencia de los
estudiantes del grado 4° de primaria de la I.E.R. Campo Hermoso sede la Flor a través del diseño
de una propuesta de intervención basada en pedagogía crítica, cuyo objetivo es permitir a los
educandos integrarse entre ellos, compartir, hacer de la escuela un campo de aprendizaje y no de
violencia. Es además un llamado del Ministerio de Educación para realizar propuestas didácticas
que mejoren los aprendizajes en los niños y transformen todos los hechos que afectan el
comportamiento emocional y psicológico. Metodológicamente es una investigación educativa que
desde la perspectiva lógica integra los métodos cualitativos con enfoque etnográfico para el estudio
de la problemática identificada como falta de cultura de paz. Es de anotar que la aplicación de los
métodos del nivel teórico y práctico permite triangular la información con el fin de identificar
causas, consecuencias y así poder implementar estrategias pedagógicas, basadas en pedagogía
crítica para posteriormente evaluar su efectividad en el mejoramiento de la convivencia de los
estudiantes del grado 4° y el impacto en su cotidianidad.The purpose of this research is to contribute to the culture of peace and non-violence of students
in grade 4 of the I.E.R. Campo Hermoso headquarters la Flor through the design of an intervention
proposal based on critical pedagogy, the objective of which is to allow students to integrate with
each other, share, make the school a field of learning and not of violence. It is also a call from the
Ministry of Education to make didactic proposals that improve learning in children and transform
all the facts that affect emotional and psychological behavior. Methodologically it is an educational
research that from the logical perspective integrates qualitative methods with an ethnographic
approach for the study of the problems identified as the lack of a culture of peace. It should be
noted that the application of the methods of the theoretical and practical level allowsthe information
to be triangulated in order to identify causes, consequences and thus be able to implement
pedagogical strategies, based on critical pedagogy, to subsequently evaluate its effectiveness in
improving the coexistence of the children. 4th grade students and the impact on their daily lives.EspecializaciónEspecialista en Investigación e Innovación Educativ
Propuesta de intervención basada en pedagogía crítica para generar cultura de paz en el aula de clase
No full textEsta investigación tiene como propósito contribuir a la cultura de paz y no violencia de los
estudiantes del grado 4° de primaria de la I.E.R. Campo Hermoso sede la Flor a través del diseño
de una propuesta de intervención basada en pedagogía crítica, cuyo objetivo es permitir a los
educandos integrarse entre ellos, compartir, hacer de la escuela un campo de aprendizaje y no de
violencia. Es además un llamado del Ministerio de Educación para realizar propuestas didácticas
que mejoren los aprendizajes en los niños y transformen todos los hechos que afectan el
comportamiento emocional y psicológico. Metodológicamente es una investigación educativa que
desde la perspectiva lógica integra los métodos cualitativos con enfoque etnográfico para el estudio
de la problemática identificada como falta de cultura de paz. Es de anotar que la aplicación de los
métodos del nivel teórico y práctico permite triangular la información con el fin de identificar
causas, consecuencias y así poder implementar estrategias pedagógicas, basadas en pedagogía
crítica para posteriormente evaluar su efectividad en el mejoramiento de la convivencia de los
estudiantes del grado 4° y el impacto en su cotidianidad.The purpose of this research is to contribute to the culture of peace and non-violence of students
in grade 4 of the I.E.R. Campo Hermoso headquarters la Flor through the design of an intervention
proposal based on critical pedagogy, the objective of which is to allow students to integrate with
each other, share, make the school a field of learning and not of violence. It is also a call from the
Ministry of Education to make didactic proposals that improve learning in children and transform
all the facts that affect emotional and psychological behavior. Methodologically it is an educational
research that from the logical perspective integrates qualitative methods with an ethnographic
approach for the study of the problems identified as the lack of a culture of peace. It should be
noted that the application of the methods of the theoretical and practical level allowsthe information
to be triangulated in order to identify causes, consequences and thus be able to implement
pedagogical strategies, based on critical pedagogy, to subsequently evaluate its effectiveness in
improving the coexistence of the children. 4th grade students and the impact on their daily lives.EspecializaciónEspecialista en Investigación e Innovación Educativ
Microcystins Detection Methods: A Focus on Recent Advances Using Molecularly Imprinted Polymers
No full textIndexación: Scopus.Microcystins (MCs) are cyclic heptapeptide toxins produced by cyanobacteria during algal blooms. Global warming and anthropogenic eutrophication have raised the occurrence of MCs to dangerous exposure levels, which represents a major threat to the safety of drinking and irrigation water. The timely detection and removal of MCs from water sources is part of the Sustainable Development Goals to achieve universal and equitable access to safe and affordable drinking water for all. Significant progress has been attained in analytical methods for MCs detection and quantification including biochemical (protein phosphatase inhibition assays (PPIA) and enzyme-linked immunosorbent assay (ELISA)), physicochemical (high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS)), and biosensor-based strategies. Improved developments in terms of sensitivity, selectivity, and affordability are expected from novel analytical tools based on molecularly imprinted polymers (MIPs), which are promising materials with specific recognition capacity and versatility for numerous applications. This review critically addresses the most relevant conventional methods for the detection of MCs and focuses on the advantages of MIP-based methods for MCs analysis. Besides, the potential of molecular modeling methods to assist in the future design of improved materials for MCs recognition is reviewed.https://pubs-acs-org.recursosbiblioteca.unab.cl/doi/10.1021/acs.analchem.1c04090The authors acknowledge Projects ANID/FONDEF VIU19E0172, ANID/FONDECYT 3200508, 3200601, 3210599, 1200204, and 1211450 and a postdoctoral scholarship from the Universidad de La Frontera.S
