Estudio físico-químico de fluidos complejos de uso cosmético

En los últimos años, el interés por el conocimiento y la comprensión del comportamiento de los fluidos complejos ha experimentado una gran evolución debido a su participación en distintos campos, incluyendo la cosmética, farmacia y tecnología de los alimentos [1-3]. En particular, el interés por estos sistemas viene desencadenado por su comportamiento en las proximidades de interfases y su capacidad para formar estructuras autoensambladas que permiten la encapsulación de principios activos. De este modo, la aplicación de los fluidos complejos en cosmética ha permitido dar un carácter más funcional a los productos para el cuidado personal.

Recent advances in biologically active coumarins from marine sources: Synthesis and evaluation

Producción CientíficaCoumarin and its derivatives have significantly attracted the attention of medicinal chemists and chemical biologists due to their huge range of biological, and in particular, pharmacological properties. Interesting families of coumarins have been found from marine sources, which has accelerated the drug discovery process by inspiring innovation or even by the identification of analogues with remarkable biological properties. The purpose of this review is to showcase the most interesting marine-derived coumarins from a medicinal chemistry point of view, as well as the novel and useful synthetic routes described to date to achieve these chemical structures. The references that compose this overview were collected from PubMed, Mendeley and SciFinder.Junta de Castilla y León - (grant VA294-P18)Ministerio de Ciencia e Innovación - (PID2020-116076RJI00/AEI/10.13039/501100011033

Diastereoselective synthesis of cis-2,6-disubstituted dihydropyrane derivatives through a competitive silyl-prins cyclization versus alternative reaction pathways

Producción CientíficaA convenient regioselective synthesis of allyl- and vinylsilyl alcohols, from a common precursor, was described, by selecting the appropriate reaction conditions. Allyl- and vinylsilyl alcohols were tested in silyl-Prins cyclizations for the preparation of disubstituted oxygenated heterocycles in a one-pot sequential reaction. The methodology was sensitive to the structure of the starting alkenylsilyl alcohol and reaction conditions, with competitive pathways observed (particularly for allylsilyl alcohols), such as Peterson elimination and oxonia-Cope reactions. However, the use of vinylsilyl alcohols allowed the preparation of differently disubstituted cis-2,6-dihydropyrans in moderate to good yields. Computational studies support the proposed mechanism.Junta de Castilla y León - (grant VA294-P18)Ministerio de Ciencia e Innovación - (PID2020-116076RJI00/AEI/10.13039/501100011033

The tetrahydrofuran motif in marine lipids and terpenes

Producción CientíficaHeterocycles are particularly common moieties within marine natural products. Specifically, tetrahydrofuranyl rings are present in a variety of compounds which present complex structures and interesting biological activities. Focusing on terpenoids, a high number of tetrahydrofuran-containing metabolites have been isolated during the last decades. They show promising biological activities, making them potential leads for novel antibiotics, antikinetoplastid drugs, amoebicidal substances, or anticancer drugs. Thus, they have attracted the attention of the synthetics community and numerous approaches to their total syntheses have appeared. Here, we offer the reader an overview of marine-derived terpenoids and related compounds, their isolation, structure determination, and a special focus on their total syntheses and biological profiles.Junta de Castilla y León - (grant VA294-P18

Changing the reaction pathway of Silyl-Prins cyclization by switching the lewis acid: Application to the synthesis of an antinociceptive compound

Producción CientíficaDeveloping new procedures for the synthesis of tetrahydropyrans in a very stereoselective manner is of great importance for the synthesis of THP-containing natural products. Here, we report an interesting protocol for the synthesis of polysubstituted halogenated tetrahydropyrans by silyl-Prins cyclization of vinylsilyl alcohols, in which the nature of the Lewis acid determines the outcome of the process. The methodology has been applied to the synthesis of a known antinociceptive.Junta de Castilla y León (VA294P18

The tetrahydrofuran motif in polyketide marine drugs

Producción CientíficaOxygen heterocycles are units that are abundant in a great number of marine natural products. Among them, marine polyketides containing tetrahydrofuran rings have attracted great attention within the scientific community due to their challenging structures and promising biological activities. An overview of the most important marine tetrahydrofuran polyketides, with a focused discussion on their isolation, structure determination, approaches to their total synthesis, and biological studies is provided.Junta de Castilla y León - (grant VA294-P18

Microrheology Of Gels Based On Polymers And On Different Colloidal Systems

Gels are ubiquitous materials in Biology and in many technological fields such as cosmetics, pharmacy, food, science. A distinctive feature of gels is their mechanical properties, which are intermediate between those of concentrated polymer solutions and of rigid solids. Focusing on the complex shear modulus, G*, the gelling point at a given temperature is frequently defined as the frequency at which the real, G’, and the imaginary, G”, contributions are equal. Understanding the gelling kinetics is another issue of key importance for designing gels under pre-specified conditions. A short cut in most papers G* is measured in a short low-range frequencies. Passive microrheology is a good tool for extending the frequency range. Despite it is only useful for the linear range, it has the advantage of enabling to probe the spatial heterogeneity. In this communication we will use passive microrheology and standard low-frequency rotational rheology to study the gelling kinetics of concentrate polysaccharide solutions at different concentration and temperatures. It has been found that the use of the extended Jeffrey’s model fits the results and allows one to calculate the short- and long-time node-node diffusion coefficients and mean node-node molecular weight. It was found that the mean-squared displacement does not only depends on the size of the particles, but also on their chemical nature because in some cases, e.g. TiO2, there can be strong particle-monomer interactions that slow down the motion of the microparticles. Similar studies have been done using gels based on colloidal systems such as lamellar phases or emulsions, including active molecules or not. More sophisticated systems are nano- or microgels inside liposomes or giant vesicles. In this case hyaluronic acid is encapsulated and then crosslinked by Fe3+ ions that diffuse through the phospholipidic membrane. In this case a heterogeneous gelling process takes place due to the gradient of Fe3+ ions from the membrane to the center of the capsule. Finally, gel-like materials are formed by adsorption of polyelectrolytes or their mixtures with surfactants from their aqueous solutions on solid substrates. Their mechanical properties at high frequencies can be estimated using a quartz-crystal microbalance with dissipation. In most cases the values of G’ are in the MHz range despite the water content inside the adsorbed film can vary between 20 and 70 wt%. Despite it is possible to follow the adsorption kinetics, the precision on G’ does not allow following the gelling kinetics in terms of the shear modulus

Estudios de caso. El desarrollo de competencias en la formación inicial de docentes en Andalucía después de Bolonia (EEES). Facultad de Ciencias de la Educación (Universidad de Córdoba)

Esta colección tiene una serie de informes generales y 8 estudios de casos. Este volumen es el informe del Estudio de casos desarrollado en la Facultad de Ciencias de la Educación de la Universidad de Sevilla. Todos los autores y autoras de este documento autorizan a Encarnación Soto Gómez a depositarlo en RIUMA.Los hallazgos de esta investigación se recogen en diferentes informes que componen una mirada compleja y contrastada a la formación inicial de Andalucía en el Grado de Educación Infantil y Educación Primaria 10 años después de la puesta en marcha del Espacio Europeo de Educación Superior y 30 años después de la investigación desarrollada por el mismo Grupo de investigación: (1991-1993) del Plan Nacional de Investigación “Las prácticas de enseñanza en la formación inicial en las escuelas universitarias de formación de profesorado de Andalucía” (PB90-0813). La colección se compone de: • Un informe documental de las estructuras, condiciones y planes de estudio de las 8 Facultades implicadas. • Un informe de grandes muestras recogiendo la opinión de estudiantes y profesorado implicado en cada uno de los Títulos • 8 estudios de caso, uno por cada una de las Facultades implicadas. Investigadores principales: Ángel I. Pérez y Encarna Soto Investigadores: Noelia Alcaraz; Javier Barquin; Nieves Blanco; Ester Caparrós; Soledad de la Blanca; Manuel Fernandez; Isabel Fernández; Monsalud Gallardo; Elena García; Rosario Gutíerrez; Gonzalo Maldonado; Diego Martín; Ana Márquez; Mª Jose Mayorga; Laura; Muñoz; Laura Pañagua; Noemí Peña; Laura Pérez; Cristina Rodríguez; Mª del Pilar Sepúlveda; Mª José Serván; Eduardo SierraProyecto de investigación financiado: UMA18-FEDERJA-127. El desarrollo de competencias en la formación inicial de docentes en Andalucía después de Bolonia (EEES). Un estudio comparativo 25 años después. Grupo de Investigación HUM 311. Web. http://repensarlaeducacion.e

Synergistic effect of nanocoatings for corrosion and wear protection of steel surfaces

The purpose of this paper is to evaluate the corrosion and wear protection of a steel substrate by epoxy vinyl ester nanocomposite coatings with Zn and TiO2 nanoparticle fillers. Steel substrates were coated with epoxy vinyl ester nanocomposites, varying Zn and TiO2 nanofiller concentrations and combinations of both nanoparticles. Corrosion resistance was evaluated by salt spray fog test during 480 h, according to ASTM B-117. The degree of damage was obtained quantitatively by measuring the enhancement in corroded area compared to the scribe mark. Tribological evaluation was performed with a ball-on-disk tribotester, according to ASTM G-99. Results showed that the combination of Zn and TiO2 nanofillers in an epoxy vinyl ester coating provide a synergistic effect, enhancing corrosion protection due to their combined corrosion and tribological reducing mechanisms. - El propósito de este trabajo es evaluar la protección contra la corrosión y el desgaste de un sustrato de acero mediante recubrimientos nanocompuestos de epoxi-vinil éster y nanopartículas de Zn y TiO2. Los sustratos de acero se recubrieron con nanocompuestos de epoxi-vinil éster, variando las concentraciones de nanopartículas de Zn y TiO2 y las combinaciones de ambas nanopartículas. La resistencia a la corrosión se evaluó mediante la prueba de niebla salina durante 480 h, según la norma ASTM B-117. El grado de daño se obtuvo cuantitativamente al medir la mejora en el área corroída en comparación con la marca trazada en los especímenes. La evaluación tribológica se realizó con una configuración de bola-sobre-disco, de acuerdo con la norma ASTM G-99. Los resultados mostraron que la combinación de nanopartículas de Zn y TiO2 en un recubrimiento epoxi-vinil éster proporciona un efecto sinérgico, mejorando la protección contra la corrosión debido a sus mecanismos combinados de corrosión y reducción tribológica