New gold-catalyzed reactions and applications for the synthesis of alkaloids

En esta Tesis Doctoral se realiza un estudio detallado de la reacción inter- e intramolecular de compuestos carbonílicos con 1,6-eninos catalizada por complejos de oro(I), racionalizando las variables que permiten la obtención selectiva de los diferentes productos, tales como compuestos tricíclicos, dihidropiranos, 1,3-dienos o ciclobutenos. Dada la importancia y dificultad de sintetizar compuesto con subunidades ciclobuteno, en el segundo capítulo se describe la obtención de compuestos con la unidad biciclo[3.2.0]hept-5-eno mediante cicloisomerización de 1,8-eninos catalizada por oro. En el último capítulo, se aplica la metodología desarrollada en el grupo para ciclación intramolecular de indoles con alquinos catalizada por complejos de oro(III) en la síntesis total de las lundurinas. Las lundurinas son un nuevo tipo de alcaloides indólicos, donde algunos derivados presentan actividad citotóxica in vitro contra células de melanoma B16.During this Doctoral Thesis a detailed study of the inter- and intramolecular reactions of carbonyl compounds with 1,6-enynes using gold(I) complexes were developed, streamlining the variables that allow the selective synthesis of different products, such as tricyclic compounds, dihydropyrans, 1,3-dienes or cyclobutenes. Given the importance and difficulty of synthesizing compounds bearing a cyclobutene subunit, in the second chapter the preparation of products is described, which include a bicyclo[3.2.0]hept-5-ene motif, via gold-catalyzed cycloisomerization of 1,8-enynes. In the last chapter, the main core of lundurines has been synthesized by appling the methodology developed in the group for the intramolecular gold-catalyzed cyclization of indoles with alkynes. Lundurines are a new type of indole alkaloids, which are characterized by an unusual carbon skeleton. Interestingly, lundurines B and D have shown significant in vitro cytotoxicity toward B16 melanoma cells

Metallization of cyanide-modified Pt(111) electrodes with copper

The support of the University of Aberdeen is gratefully acknowledged. CW acknowledges a summer studentship from the Carnegie Trust for the Universities of Scotland.Peer reviewedPostprin

Cyanide-modified Pt(111) : structure, stability and hydrogen adsorption

A.C. acknowledges the support of the DGI (Spanish Ministry of Science and Innovation) through Project CTQ2009-07017. W.S. acknowledges financial support by the Deutsche Forschungsgemeinschaft under Schm 344/40-1, Schm 344/34-1.2 and FOR 1376. W.S. and P.Q. thank DFG-CONICET International Cooperation and CONICET for continued support. E.P.M.L. and M.Z.-M. wish to acknowledge CONICET PIP: 112-200801-000983, Secyt UNC, Program BID (PICT 2006N 946), and PME: 2006-01581 for financial support. P.Q. acknowledges PICT 0737-2008. A generous grant of computing time from the Baden-Wuerttemberg grid is gratefully acknowledged. M.E.-E. acknowledges an FPI fellowship from the Spanish Ministry of Science and Innovation and an accommodation grant at the Residencia de Estudiantes from the Madrid City Council.Peer reviewedPostprin

Northernmost record of the pantropical portunid crab <i>Cronius ruber</i> in the eastern Atlantic (Canary Islands): natural range extension or human-mediated introduction?

The pantropical crab Cronius ruber (Lamarck, 1818) (Brachyura: Portunidae) is recorded for the first time from the Canary Islands. Previously known from off Cape Verde Islands and Senegal, this is the northernmost record of the species in the eastern Atlantic Ocean. Crabs have been caught by means of a collecting small trap for sampling in shallow waters, and then identified by both morphological characters and DNA barcoding (16S). Cytochrome c oxidase I partial sequence has been obtained for this species for the first time. This relatively large and very aggressive crab species seems to be rapidly occupying both hard substrates (sublittoral caves) and soft substrates (sand with seagrass meadow) adjacent to shallow rocky bottoms, at depths between 2 and 10 m, in the warm southern waters of Gran Canaria Island. The reasons for this species’ occurrence are discussed herein. Among them, natural range extension may be a consequence of tropicalization in the eastern Atlantic. Also, a human-mediated introduction could be based on the heavy traffic of ships (ballast waters or oil platforms) arriving at the Canary Islands from African countries and from Brazil in the last decade

Evolution of social relationships between first-year students at middle school: from cliques to circles

People organize their social relationships under a restriction on the number that a single individual can maintain simultaneously (the so-called Dunbar’s number, ~150). Additionally, personal networks show a characteristic layered structure where each layer corresponds to relationships of different emotional closeness. This structure, referred to as Dunbar’s circles, has mostly been considered from a static viewpoint, and their structure and evolution is largely unexplored. Here we study the issue of the evolution of the structure of positive and negative relationships in early adolescence by using data from students in their first year at middle school obtained from surveys conducted in class in two different waves separated by several months. Our results show that, initially, students have a lower number of total relationships but the majority are more intense and over time they report a higher number of total relationships, but the more intense relationships appear in a lower proportion. We have also found differences in the structure of communities at both temporal moments. While in the first instance the communities that appeared are mixed, made up of both boys and girls, in the second they changed so that they were separated primarily by gender. In addition, the size of each community was stabilized around 15 people, which coincides with the size of the second Dunbar’s circle, known as the sympathy group in social psychology. As a consequence, in groups with around 20 students of the same gender, they tend to split in two separate communities of about 10 each, below the second Dunbar’s circle threshold. On the other hand, groups with more stable community structure appear to go through the inverse process of friendship evolution, becoming more focused on their best relationships. All these results suggest how the layered structure of the personal network, as well as the community structure of the social network, emerge directly from the union of both positive and negative relationships. Thus, we provide a new perspective about its temporal evolution that may have relevant applications to improve school life and student performance. © 2021, The Author(s)

Stability of the personal relationship networks in a longitudinal study of middle school students

The personal network of relationships is structured in circles of friendships, that go from the most intense relationships to the least intense ones. While this is a well established result, little is known about the stability of those circles and their evolution in time. To shed light on this issue, we study the temporal evolution of friendships among teenagers during two consecutive academic years by means of a survey administered on five occasions. We show that the first two circles, best friends and friends, can be clearly observed in the survey but also that being in one or the other leads to more or less stable relationships. We find that being in the same class is one of the key drivers of friendship evolution. We also observe an almost constant degree of reciprocity in the relationships, around 60%, a percentage influenced both by being in the same class and by gender homophily. Not only do our results confirm the mounting evidence supporting the circle structure of human social networks, but they also show that these structures persist in time despite the turnover of individual relationships -- a fact that may prove particularly useful for understanding the social environment in middle schools.Comment: 10 pages, 7 figures, requires wlscirep.cls, jabbrv.sty, jabbrv-ltwa-all.ldf, and jabbrv-ltwa-en.ldf (included

Electrooxidation of formic acid on gold : An ATR-SEIRAS study of the role of adsorbed formate

Funding from the DGI (Spanish Ministry of Education and Science) through Projects CTQ2009-07017 and PLE2009-0008 is gratefully acknowledged. M.E.-E. acknowledges an FPI fellowship from the Spanish Ministry of Science and Innovation and an accommodation grant at the Residencia de Estudiantes from the Madrid City Council. C. V.-D. acknowledges a JAE-Doc fellowship from CSIC.Peer reviewedPostprin

Chimpanzees organize their social relationships like humans

Human relationships are structured in a set of layers, ordered from higher (intimate relationships) to lower (acquaintances) emotional and cognitive intensity. This structure arises from the limits of our cognitive capacity and the different amounts of resources required by different relationships. However, it is unknown whether nonhuman primate species organize their affiliative relationships following the same pattern. We here show that the time chimpanzees devote to grooming other individuals is well described by the same model used for human relationships, supporting the existence of similar social signatures for both humans and chimpanzees. Furthermore, the relationship structure depends on group size as predicted by the model, the proportion of high-intensity connections being larger for smaller groups

Virtual reality and augmented reality proposals for the museum of the 21st Century as laboratory and educational space

[EN] At the end of the XX Century, medialabs, working as crosssectional and participatory research and production laboratories, began to be elementary within the historical and cultural context of the moment. They represented a strong and clear symbol of the transition from the individual to the collective action construct. In a similar manner, the centers for the citizens emerged as a paradigm of the cultural phenomenon in the following century. The genesis of the lab concept is in its forthright dialogue with society; a media laboratory linked to the social context where it is embedded. Collaboration and citizen participation, social activism in a co-creation process in which the citizen is empowered at the command of shaping the sense that the communication technologies should have. The citizen becomes the main character for the conformation of the digital culture, which belongs to him/her. And is not this prospective what 21st century museums should have, especially if they operate in the digital context? From the philosophical conception suggested by Aby Warburg about the images in a dynamic, visual, changing, mutable and open space, where time takes a different meaning, an innovative proposition for the virtual museography of the 21st century is suggested. Thus, in order to approach the pattern of a virtual museum, it is necessary to identify the breach between the museum understood as a place for exhibition and contemplation, and another one with a temporal/virtual/space new lawyer where interaction becomes the engine and instant moment of the artwork. It goes from an object to a work-in-process artwork in which the collaborative and educational concepts hold on new meanings. It is about deconstructing the space of museums and classrooms to build up the space of the digital and its narratives. Multimodality is going to drive the main methodological line for the development of an interactive narrative, promoting different methods and techniques in a virtual museum space through immersive and semi-immersive experiences, offering proposals through both platforms. Taking these objectives, methodologies and technological proposals, such as virtual and augmented reality, methodological models will be obtained to develop original narratives in a unique museum concept as a laboratory and educational digital space.[ES] A finales del siglo XX, los medialab, como laboratorios de investigación y producción transversal y participativos, comenzaron a ser fundamentales dentro del contexto histórico y cultural del momento, como un símbolo claro del paso del constructo de acción individual hacia la colectiva. Del mismo modo, los centros ciudadanos comenzaron a emerger en el siglo siguiente como paradigma del fenómeno cultural. La génesis del concepto lab está en su diálogo directo con la sociedad, un laboratorio de medios, vinculado el contexto social en el que se imbrica. Colaboración y participación ciudadana, activismo social en un proceso de co-creación donde el propio ciudadano se empodera en la potestad de conformar el sentido que considera que deben tener las tecnologías de la comunicación. Él es protagonista de la conformación de la cultura digital, la cual le pertenece. ¿Y, no es esto en lo que se están convirtiendo o deberían convertirse los museos del siglo XXI y más, si desarrollan su actividad en el contexto digital? Desde la concepción filosófica propuesta por Aby Warburg de las imágenes en un espacio visual dinámico, cambiante, mudable y abierto, en donde el tiempo toma un nuevo sentido, nos planteamos una nueva propuesta de la museografía virtual del siglo XXI. Así pues, para aproximarnos a la modelización de un museo virtual se hace necesario que identifiquemos la ruptura entre el museo como lugar solo para exposición y contemplación, de aquel en el cual se propone una nueva capa/espacio/temporal/virtual donde la interacción se convierte en el motor y momento de la obra. Se pasa de una obra objeto a obra en proceso en el que lo colaborativo y educativo toman nuevos sentidos. Se trata de deconstruir el espacio de los museos y de las aulas para construir el espacio propio de lo digital, de sus narrativas. La multimodalidad marcará la línea metodológica central para el desarrollo de una narrativa interactiva, propiciando métodos y técnicas, en un espacio de museo virtual mediante experiencia inmersiva y seminmersiva, planteando propuestas en ambas plataformas. Desde estos objetivos, metodologías y propuestas tecnológicas como la realidad virtual y aumentada, obtendremos modelos metodológicos para desarrollar narrativas propias del espacio digital en un concepto de museo como laboratorio y espacio educativo.Tortosa Cuesta, R.; Caerols Mateo, R.; Escribano Belmar, B.; Rodríguez Calatayud, MN. (2022). Propuestas de realidad virtual y aumentada para el museo del s XXI como laboratorio y espacio educativo. En CIMED21 - I Congreso internacional de museos y estrategias digitales. Editorial Universitat Politècnica de València. 101-117. https://doi.org/10.4995/CIMED21.2021.1246010111

Embalagem plástica para flocão de milho biofortificado.

Devido a carência de micronutrientes que são essenciais para a saúde, vem sendo desenvolvido no Brasil produtos biofortificados. O objetivo desse estudo foi levantar informações sobre os efeitos de quatro tipos de embalagem e do tipo de acondicionamento (com e sem vácuo), na perda de qualidade de flocão de milho biofortificado. Os resultados mostraram que em todas as embalagens avaliadas houve preservação dos carotenoides, tendo um destaque para o PETmet/PEBD com vácuo que teve uma maior retenção do teor de carotenoides pró-vitamina A e maior preservação da cor.22 a 26 de outubro de 2017