Planificación de la enseñanza basada en problemas en asignaturas del área de Química Física

El proceso de enseñanza-aprendizaje denominado Aprendizaje Basado en Problemas (ABP) es una metodología que concita cada vez un mayor interés. Esta metodología ha sido probada con éxito tanto en diferentes niveles educativos como en diferentes áreas de conocimiento generando un aprendizaje significativo en que el protagonista es el alumno, generando a su vez una mayor motivación. La organización tradicional del proceso enseñanza-aprendizaje, incluso con el empleo de nuevas tecnologías, no siempre ha dado lugar a resultados positivos en la motivación e implicación del alumnado en dicho proceso. Es por eso que se requiere el empleo de nuevas metodologías que nos permitan obtener unos resultados más satisfactorios del proceso educativo. El ABP fomenta el desarrollo de habilidades dirigidas hacia un pensamiento racional, crítico y creativo. Este tipo de habilidades si bien son deseables en todo ámbito de conocimiento son imprescindibles en el aprendizaje de materias relacionadas con el ámbito científico, y en concreto de la Química Física, ya que se trata de habilidades perdurables que permiten estudiar e investigar a lo largo de la vida. Las asignaturas del área de la Química Física se encuentra generalmente incluidas dentro de aquellas que mayor dificultad de aprendizaje presentan, por lo que conviene tratar de reflexionar sobre los posibles cambios metodológicos para su enseñanza y proponer las líneas de trabajo para poder implementar dichos cambios

Improving the Stability and Efficiency of CuO Photocathodes for Solar Hydrogen Production through Modification with Iron

Cupric oxide (CuO) is considered as a promising photocathode material for photo(electro)chemical water splitting because of its suitable band gap, low cost related to copper earth abundancy, and straightforward fabrication. The main challenge for the development of practical CuO-based photocathodes for solar hydrogen evolution is to enhance its stability against photocorrosion. In this work, stable and efficient CuO photocathodes have been developed by using a simple and cost-effective methodology. CuO films, composed of nanowires and prepared by chemical oxidation of electrodeposited Cu, develop relatively high photocurrents in 1 M NaOH. However, this photocurrent appears to be partly associated with photocorrosion of CuO. It is significant though that, even unprotected, a faradaic efficiency for hydrogen evolution of ∼45% is attained. The incorporation of iron through an impregnation method, followed by a high-temperature thermal treatment for promoting the external phase transition of the nanowires from CuO to ternary copper iron oxide, was found to provide an improved stability at the expense of photocurrent, which decreases to about one-third of its initial value. In contrast, a faradaic efficiency for hydrogen evolution of ∼100% is achieved even in the absence of co-catalysts, which is ascribable to the favorable band positions of CuO and the iron copper ternary oxide in the core–shell structure of the nanowires.Authors are grateful to MINECO of Spain for the financial support through project MAT2015-71727-R (FONDOS FEDER). A.C. wants to acknowledge the University of Alicante for a predoctoral grant (FPU-UA)

Guidelines for the design of efficient sono-microreactors

Possible drawbacks of microreactors are inefficient reactant mixing and the clogging of microchannels when solid-forming reactions are carried out or solid (catalysts) suspensions are used. Ultrasonic irradiation has been successfully implemented for solving these problems in microreactor configurations ranging from capillaries immersed in ultrasonic baths to devices with miniaturized piezoelectric transducers. Moving forward in process intensification and sustainable development, the acoustic energy implementation requires a strategy to optimize the microreactor from an ultrasound viewpoint during its design. In this work, we present a simple analytical model that can be used as a guide to achieving a proper acoustic design of stacked microreactors. An example of this methodology was demonstrated through finite element analysis and it was compared with an experimental study found in the literature.This research is funded by the EU project MAPSYN: Microwave, Acoustic and Plasma SYNtheses, under grant agreement No. CP-IP 309376 of the European Union Seventh Framework Program

A "Know-How vs. Know-What" Approach in the Teaching-Learning of Competences in Physical Chemistry

The methodological approach a teacher uses in the competence teaching-learning process determines the way students learn. Knowledge can be acquired from a series of perspectives, mainly: “know-what” (concept), where facts and descriptions of (natural or social) phenomena are pursued; “know-how” (procedure), where methods and procedures for their application are described; and “know-why” (competence), where general principles and laws that explain both the facts and their applications are sought. As all the three cases are interconnected, the boundaries between them are not fully clear and their application uses shared elements. In any case, the depth of student’s acquired competences will be directly affected by the teaching-learning perspective, traditionally aiming to a “know-why” approach for full competence acquisition. In this work, we discuss a suitable teaching-learning methodology for evaluating whether a “know-how”, “know-what” or combined approach seems better for enhancing competence learning in students. We exemplify the method using a selection of formative activities from the Physical Chemistry area in the Grades of Chemistry and Chemical Engineering

Comparative Photo-Electrochemical and Photocatalytic Studies with Nanosized TiO2 Photocatalysts towards Organic Pollutants Oxidation

The size of TiO2 can significantly affect both its photocatalytic and photo-electrochemical properties, thus altering the photooxidation of organic pollutants in air or water. In this work, we give an account of the photo-electrochemical and photocatalytic features of some nanosized TiO2 commercial powders towards a model reaction, the photooxidation of acetone. Cyclic voltammograms (CV) of TiO2 particulate electrodes under UV illumination experiments were carried out in either saturated O2 or N2 solutions for a direct correlation with the photocatalytic process. In addition, the effect of different reaction conditions on the photocatalytic efficiency under UV light in both aqueous and gaseous phases was also investigated. CV curves with the addition of acetone under UV light showed a negative shift of the photocurrent onset, confirming the efficient transfer of photoproduced reactive oxygen species (ROSs), e.g., hydroxyl radicals or holes to acetone molecules. The photocatalytic experiments showed that the two nano-sized samples exhibit the best photocatalytic performance. The different photoactivity of the larger-sized samples is probably attributed to their morphological differences, affecting both the amount and distribution of free ROSs involved in the photooxidation reaction. Finally, a direct correlation between the photocatalytic measurements in gas phase and the photo-electrochemical measurements in aqueous phase is given, thus evincing the important role of the substrate-surface interaction with similar acetone concentrations.This work has been developed in part in the context of project RTI2018–102061–B–I00 financed by FEDER/Ministerio de Ciencia e Innovación-Agencia Estatal de Investigación

Effects of Ultrasound Irradiation on the Synthesis of Metal Oxide Nanostructures

High intensity ultrasound can be used for the production of novel nanomaterials, including metal oxides. According to previous works in this field, the most notable effects are consequence of acoustic cavitation. In this context, we have studied the preparation of different materials in the presence of ultrasound, including N-doped TiO2 nanopowder, NiTiO3 nanorods and MnOx thin films. Ultrasound did not show a significant effect in all the cases. Exclusively for NiTiO3 nanorods a reduction of the final particle size occurs upon ultrasonic irradiation. From these results, it can be concluded that the ultrasound irradiation does not always play a key role during the synthesis of metal oxides. The effects seem to be particularly relevant in those cases where mass transport is highly hindered and in those procedures that require the rupture of nanoparticle aggregates to obtain a homogenous dispersion.We want to acknowledge the Spanish Ministry of Economy and Competitiveness (MINECO) for financial support through projects PRI-PIBIN-2011-0816 and MAT2012-37676 (FONDOS FEDER). V. Manzi-Orezzoli is grateful to the Universitat d’Alacant for the award of a research initiation grant

Assessment of Competences in the Physical Chemistry Area: Use of the Department Teaching Portfolio

Competences have become a standard learning outcome in present university education within the European Higher Education Area (EHEA). In this regard, updated tools for their assessment have turned out essential in this new teaching-learning paradigm. Among them, one of the most promising tools is the “learner´s portfolio”, which is based on the gathering and evaluation of a range of evidences from the student, which provides a wider and more realistic view of his/her competence acquisition. Its appropriate use as a formative (continuous) assessment instrument allows a deeper appraisal of student´s learning, provided it does not end up as another summative (final) evaluation tool. In this contribution we propose the use of the portfolio as a unifying assessment tool within a university department (Physical Chemistry), exemplifying how the portfolio could yield both personalized student reports and averaged area reports on competence acquisition. A proposed stepwise protocol is given to organize the individual competence reports and estimate the global competence level following a bottom-up approach (i.e. ranging from the class group, subject, grade, and academic course)

A photoredox-neutral Smiles rearrangement of 2-aryloxybenzoic acids

We report on the use of visible light photoredox catalysis for the radical Smiles rearrangement of 2-aryloxybenzoic acids to obtain aryl salicylates. The method is free of noble metals and operationally simple and the reaction can be run under mild batch or flow conditions. Being a redox neutral process, no stoichiometric oxidants or reductants are needed.This work was supported by the Ministerio de Economia y Competitividad (MAT2016-78625-C2-2-P, MAT2015-71727-R) and the Universidad de Alicante (VIGROB-173). N. P. R. thanks the Instituto de Sintesis Organica (ISO) for a grant

Nitrogen regulation of protein–protein interactions and transcript levels of GlnK PII regulator and AmtB ammonium transporter homologs in Archaea

Gene homologs of GlnK PII regulators and AmtB-type ammonium transporters are often paired on prokaryotic genomes, suggesting these proteins share an ancient functional relationship. Here, we demonstrate for the first time in Archaea that GlnK associates with AmtB in membrane fractions after ammonium shock, thus, providing a further insight into GlnK-AmtB as an ancient nitrogen sensor pair. For this work, Haloferax mediterranei was advanced for study through the generation of a pyrE2-based counterselection system that was used for targeted gene deletion and expression of Flag-tagged proteins from their native promoters. AmtB1-Flag was detected in membrane fractions of cells grown on nitrate and was found to coimmunoprecipitate with GlnK after ammonium shock. Thus, in analogy to bacteria, the archaeal GlnK PII may block the AmtB1 ammonium transporter under nitrogen-rich conditions. In addition to this regulated protein–protein interaction, the archaeal amtB-glnK gene pairs were found to be highly regulated by nitrogen availability with transcript levels high under conditions of nitrogen limitation and low during nitrogen excess. While transcript levels of glnK-amtB are similarly regulated by nitrogen availability in bacteria, transcriptional regulators of the bacterial glnK promoter including activation by the two-component signal transduction proteins NtrC (GlnG, NRI) and NtrB (GlnL, NRII) and sigma factor σN (σ54) are not conserved in archaea suggesting a novel mechanism of transcriptional control

Mejora en la docencia en biociencias mediante la metodología basada en resolución de problemas

La nueva metodología docente propuesta se basa en trabajar los conceptos de la asignatura de Bioquímica, en el Grado de Nutrición Humana y Dietética, mediante vídeos colgados en Youtube. Estos vídeos recogen la parte teórica de la asignatura, explicada mediante PowerPoint. En clase podemos trabajar cuestionarios sobre los diferentes temas. El objetivo es no centrar la clase teórica en la presentación de los diferentes temas que componen el temario de la asignatura. La presentación primera la hacemos mediante los vídeos, para poder centrar el valioso tiempo de las clases en profundizar en los contenidos mediantes cuestiones y otros puntos de interés, que van sugiriendo los propios alumnos. Los vídeos, en cierta forma, sustituyen a la clase magistral clásica. En resumen, la metodología docente se basa en un sistema de presentación de los temas online y una profundización de los contenidos en clase, buscando siempre la participación activa del alumnado, de forma que el profesor no sea sólo alguien que enseña una materia, sino que sea alguien que acompaña en el proceso de aprendizaje del alumno. La parte activa del aprendizaje se basa en el trabajo del alumnado y no en el profesor