37 research outputs found

    An approach to the hillfort settlement in the Valley of Laciana (Villablino, León)

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    The development of an archaeological excavation season in three of the hillfort settlements catalogued in the shire of Laciana (northwestern León region): La Muela, La Zamora and La Laguna, has revealed the presence of numerous stone structures in these three sites, also having documented a total of five different wall sections, as well as several evidences of the interior habitat of the villages. In the first two settlements, the recovered materials seem to point out a wide time frame ranging from the protohistoric period to the second century a.C. Meanwhile, due to the lack of movable findings, the contextualization of La Laguna has to be carried out following the morphological characteristics of its emplacement. The abundance of hillfort excavations in nearby regions of Asturias and León permits us to contextualize duly the vestiges found, organizing them in two sections: defensive systems and habitat structures. Finally a series of hypothesis related to the nature of the sites are presumed, particularly with regard to the possibility of a seasonal occupation in La Muela’s hillfort.El desarrollo de una campaña de excavaciones en tres de los asentamientos castreños catalogados en la comarca de Laciana (noroeste de la provincia de León): La Muela, La Zamora y La Laguna, ha puesto de manifiesto la presencia de abundantes estructuras pétreas en los tres yacimientos, documentándose un total de cinco lienzos amurallados distintos así como diversas evidencias del hábitat interior de los poblados. Los materiales recuperados parecen señalar en los dos primeros casos unas amplias horquillas temporales que abarcan desde época protohistórica hasta el siglo II d.C., mientras que en La Laguna la ausencia de hallazgos muebles depara que su contextualización se realice a partir de las características morfológicas del emplazamiento. La abundancia de excavaciones en ámbitos castreños de zonas cercanas en Asturias y León permite encuadrar convenientemente los vestigios exhumados, organizándose éstos en dos apartados: sistemas defensivos y estructuras de hábitat. Por último, se avanzan una serie de hipótesis relativas a la naturaleza de los enclaves, fundamentalmente en lo que respecta a la posibilidad de una ocupación estacional en el Castro de La Muela para época astur vinculada al cercano asentamiento de La Zamora

    Molybdenum-Catalyzed Synthesis of Nitrogenated Polyheterocycles from Nitroarenes and Glycols with Reuse of Waste Reduction By-product

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    A novel domino reduction/imine formation/intramolecular cyclization/oxidation for the efficient synthesis of pyrrolo(indolo)[1,2-a]quinoxalines and pyrrolo(indolo)[3,2-c]-quinolines from readily available nitrobenzenes and glycols is reported. The process utilizes the carbonyl byproduct of the initial dioxomolybdenum(VI)-catalyzed reduction of nitroaromatics with glycols as a reagent for the imine generation. This method represents the first sustainable domino reaction for the preparation of biologically relevant heterocycles that internally incorporates the waste formed in the first step to the final product.Junta de Castilla y León and FEDER (BU076U16) and Ministerio de Economía y Competitividad (MINECO) (CTQ2015-70371-REDT and CTQ2016-75023- C2-1-P

    Mo–Catalyzed One-Pot Synthesis of N-Polyheterocycles from Nitroarenes and Glycols with Recycling of the Waste Reduction Byproduct. Substituent-Tuned Photophysical Properties

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    A catalytic domino reduction–imine formation– intramolecular cyclization–oxidation for the general synthesis of a wide variety of biologically relevant N-polyheterocycles, such as quinoxaline- and quinoline-fused derivatives, and phenanthridines, is reported. A simple, easily available, and environmentally friendly dioxomolybdenum(VI) complex has proven to be a highly efficient and versatile catalyst for transforming a broad range of starting nitroarenes involving several redox processes. Not only is this a sustainable, stepeconomical as well as air- and moisture-tolerant method, but also it is worth highlighting that the waste byproduct generated in the first step of the sequence is recycled and incorporated in the final target molecule, improving the overall synthetic efficiency. Moreover, selected indoloquinoxalines have been photophysically characterized in cyclohexane and toluene with exceptional fluorescence quantum yields above 0.7 for the alkyl derivatives.Junta de Castilla y León and FEDER (BU291P18 and BU049P20) and Ministerio de Economía y Competitividad (MINECO) and FEDER (CTQ2016-75023-C2-1P) for financial support. The project leading to these results has also received funding from “la Caixa” Foundation, under the agreement (LCF/PR/PR18/51130007) (CAIXA-UBU001). R.H.-R. thanks Ministerio de Educación for a FPU predoctoral contract. S.S P. thanks Junta de Castilla y León and FSE and FEDER for a postdoctoral contract

    On the Tunability of Toxicity for Viologen‐Derivatives as Anolyte for Neutral Aqueous Organic Redox Flow Batteries

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    Viologen-derivatives are the most widely used redox organic molecules for neutral pH negative electrolyte of redox flow batteries. However, the long-established toxicity of the herbicide methyl-viologen raises concern for deployment of viologen-derivatives at large scale in flow batteries. Herein, we demonstrate the radically different cytotoxicity and toxicology of a series of viologen-derivatives in in vitro assays using model organisms representative of human and environmental exposure, namely human lung carcinoma epithelial cell line (A549) and the yeast Saccharomyces cerevisiae. The results show that safe viologen derivatives can be molecularly engineered, representing a promising family of negolyte materials for neutral redox flow batteries.The authors acknowledge financial support by the Spanish Government (Ministerio de Ciencia e Innovacion, Grants PID2021-124974OB-C22 and PID2020-115789GB-C21) and Ramon y Cajal award (RYC2018-026086-I) as well as the MeBattery project. MeBattery has received funding from the European Innovation Council of the European Union under Grant Agreement no. 101046742. This work was supported by the Regional Government of Castilla y Leon (Junta de Castilla y Leon) and by the Ministry of Science and Innovation MICIN and the European Union NextGenerationEU/PRTR. We also gratefully acknowledge Junta de Castilla y Leon (BU049P20) and FEDER for financial support

    Allochthonous terranes involved in the Variscan suture from NW Iberia: a review of their origin and tectonothermal evolution [Abstract]

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    NW Iberia includes a rather complete section of the Variscan suture, where different terranes with continental or oceanic affinities appear with clear structural relationships. Three groups of terranes, namely upper, ophiolitic and basal units and a frontal tectonic mélange appear in Galicia, in Cabo Ortegal, Órdenes and Malpica-Tui complexes. They constitute a huge allochthonous pile thrust over the Iberian parautochthonous and autochthonous domains, which represent the section of the Gondwanan margin that escaped continental subduction during the Variscan cycle (Schistose Domain of Galicia-Trás-os-Montes and Central Iberian Zone)Departamento de Petrología y Geoquímica, Universidad Complutense de Madrid, EspañaInstituto de Geociencias, Universidad Complutense de Madrid, EspañaInstituto de Geociencias, Consejo Superior de Investigaciones Científicas, EspañaDepartamento de Geología, Universidad de Salamanca, EspañaInstitut für Geowissenschaften, Mineralogie, Johann Wolfgang Goëthe-Universität, AlemaniaUnidad de Tres Cantos, Instituto Geológico y Minero de España, EspañaCentro de Apoyo a la Investigación de Geocronología y Geoquímica Isotópica, Universidad Complutense de Madrid, Españ

    Cadomian and Variscan sutures of Iberia: a comparison

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    p.11-12. -A meeting held as a tribute to Teodoro Palacios on his retirement as Professor of Palaeontology at the University of Extremadura, Badajoz, Spain, 26th & 27th January, 2022, University of Extremadura, Badajoz. Edited by Sören Jensen[EN] The Iberian Massif holds evidence of two pre-Mesozoic orogenies, namely the Cadomian and Variscan. The Cadomian Orogeny resulted from long-lived subduction under the periphery of Gondwana during the Neoproterozoic and early Paleozoic. The Variscan Orogen resulted from the progressive collision of Gondwana, Laurussia and their pericontinental terranes during the Devonian and Carboniferous, after the closure of the Rheic Ocean and other marginal basins located along their mainlands. Despite these two orogens differ from one another in the global context from which they emerged, in Iberia they share some characteristics that make them intriguingly alike. The Variscan Orogen contains two major sutures zones. One that separates mainland Gondwana from peri-Gondwanan terranes (intra-Gondwana suture), and another one separating Laurussia from the latter terranes (Rheic suture). The Variscan intra-Gondwana suture is Tectonically dismembered and separates a collection of terranes with continental crust affinity that were transported inland from the periphery of Gondwana during the closure of a (Devonian) marginal basin opened during ongoing convergence between Gondwana and Laurussia (e.g., Careón Ophiolite), ⁓15 million years after the onset of the Variscan Orogen. This process was the result of subduction polarity towards Laurussia, i.e. away from mainland Gondwana. The exhumation of the ophiolites and high-P rocks in this suture was largely controlled by syn-convergence extensional tectonics. The current structure of the Rheic suture, on the other hand, is the result of reworking after the opening of an ephemeral oceanic basin (Beja-Acebuches Ophiolite). Subduction polarity during both the closure of the primary suture zone and the closure of the ephemeral basin were beneath mainland Gondwana. However, the closure of the ephemeral basin developed flake tectonics and obduction of pieces of the ocean basin onto the upper plate. Suture zones in the Cadomian Orogen went unnoticed until few years ago. Despite being intensely reworked by Variscan deformation, the ongoing structural, tectonometamorphic, geochemical and geochronological studies provide first-order constrains on their primary (Cadomian) geometry as well as insight on the paleogeographic location of subduction zones that led to their formation. A collective, yet preliminary analysis of these sutures, pictures a major architecture of the Cadomian Orogen that contain, at least, two sutures zones. One Cadomian suture is identified in the Mérida Ophiolite, which separates an upper and lower plate, both with continental crust affinity and likely Gondwanan derivation (intra-Gondwana suture). This intra-Gondwana suture was formed after the closure by subduction away from mainland Gondwana of a marginal basin that opened during ongoing convergence between Gondwana and an oceanic plate, millions of years after the onset of the Cadomian Orogen. The exhumation of the ophiolite and mid-P rocks that make this suture was largely controlled by syn-convergence extensional tectonics. Another Cadomian suture is represented by the Calzadilla Ophiolite, whose protoliths formed in a fore-arc basin to the most external part of Gondwana. The location of this suture zone is explained by flake tectonics, which contributed to the obduction of the ophiolite onto the upper plate while ongoing subduction was beneath mainland Gondwana. Cadomian and Variscan sutures share fundamental characteristics regarding the paleolocation of the ocean basins they derive from and the overall resulting geometry and tectonic processes involved in their formation. The suture zones that represent the closure of basins located at the outermost section of peri-Gondwana, and closely facing subduction underneath Gondwana (Calzadilla and Beja-Acebuches ophiolites), were obducted inwards onto mainland Gondwana (upper plate). The intra-Gondwana suture zones (Careón and Mérida ophiolites) formed after subduction of a marginal basin beneath the periphery of Gondwana, and the exhumation of rock units of the subduction system was largely assisted by syn-convergence extensional tectonics following subduction-accretion. The Variscan and Cadomian orogens, despite being formed in different contexts (oceanic subduction vs. continental collision), share two major features. Both are (i) mostly built by Gondwanan lithosphere, and (ii) occupy the upper plate of a subduction zone that consumed a large ocean. These two orogens alternate phases of contraction and extension (mostly concentrated in the upper plate). In both cases, extension was intense enough as to create marginal ocean basins and to favor exhumation of deep-seated rocks (quite common in upper plates). Perhaps, these major features they share may explain the resemblance of the final global architecture of these two orogens, and provide additional arguments to consider Gondwana as resistant to subduction and recycling in the mantle and prone to crustal growth, being the upper plate to the orogenic systems it was involved in during at least 300 m.y.Peer reviewe

    Curso abierto de ayuda para la elaboración del Trabajo Fin de Grado en los Grados en Química e Ingeniería Química

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    Este proyecto llevará a cabo el desarrollo de un curso abierto que sirva a los estudiantes como guía de ayuda a la hora de elaborar su Trabajo Fin de Grado (TFG) en los Grados de Química e Ingeniería Química. Se incluirá una descripción de herramientas que los estudiantes puedan emplear en el desarrollo de sus TFG. Éstas serán seleccionadas de acuerdo con la experiencia de los miembros del Grupo y en función de las necesidades de los estudiantes. El curso resultante se editará para libre acceso a través del portal iTunes U, de ámbito internacional, convirtiéndose en el primer curso UCM ofertado en esta plataforma (tras consulta y aprobación del Vicerrectorado de Innovación; de no ser así, se alojará en alguna otra plataforma de amplia difusión). Se aprovechará la accesibilidad ofertada a los estudiantes por iTunes U para poner a su disposición el material elaborado logrando una gran difusión, incrementándose la visibilidad internacional de la UCM. El material de ayuda elaborado para el curso se presentará tanto en español como en inglés, para facilitar su uso por alumnos visitantes de la UCM, favoreciendo la movilidad de los estudiantes en el marco del EEES. Este material también se adaptará para poder ser empleado de forma directa, totalmente o en forma de módulos, en el Campus Virtual UCM
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