Synthesis and structural studies of a dimeric bis(oxamate) copper(II) complex

A new series of a dimeric bis(oxamato) copper(II) complex of formula M4[Cu(oeo)]2 (where Et2H2(oeo) is diethyl ethylene-1,2-dioxamate and M = alkali metal) is described. The complex is formed by two copper(II) atoms and two ligand molecules of which each oxamato group is coordinating towards two different copper(II) ions leading to a distorted square planar environment. Due to the trans-bis(N,O) arrangement around the copper(II) ion, the dimer displays a helicoidal structure. We present here detailed structural studies of this complex with a number of counter ions. Many polymorphs and hydrates are observed and their synthesis and structures are described. A sequential strategy has been developed in which starting from the ligand precursor, Et2H2oeo, the addition of alkali metal hydroxides affords the hydrolysis of the ester leading to the formation of the salt of the ester, M2H2oeo. Then, transmetallation of the alkali metal salt is carried out with the addition of a copper(II) salt. The dimeric copper(II) complex, M4[Cu(oeo)]2, is finally achieved with the addition of the corresponding alkali metal hydroxide. Structural studies of the intermediate compounds are also described. The partial occupancy in the copper(II) site is a common feature in M4[Cu(oeo)]2. Surprisingly, the copper(II) site can be left vacant and the compound still remain with the same helicoidal structure as the non-coordinated ligand, when the amide is protonated, adopting a structurally similar H-bond arrangement. A wide range of copper(II) occupancies have been observed in the different obtained compounds: from compounds with a fully occupied site to compounds with only 10% of copper(II)present in the complex . These differences in the amount of copper(II) present in the complex has consequences in its packing in the crystal structure. The synthesis and characterisation of the copper(II) complex using tetrabutylammonium hydroxide as the counterion is also reported. As a result of the bulky nature of the cation, the mononuclear structure is observed, (n-Bu4N)4[Cu(oeoH)2]. Initial transmetallation reactions are reported with Co(II), in which partial and complete exchange from Cu(II) is observed

New approaches to the lithiation kinetics in reaction-limited battery electrodes through electrochemical impedance spectroscopy

Electrochemical impedance spectroscopy is a widely employed technique probing kinetic limitations in the charging of battery electrodes. Hindrance mechanisms locate at the interfaces between the active material and the electrolyte, and in the bulk of the reacting compound. Rate-limiting mechanisms are viewed as resistive circuit elements and can be extracted using standard impedance analyzers. Classical impedance models consider charge transport, mainly ion diffusion as slower carrier, as the principal kinetic limitation impeding full electrode charging. This is indeed the case for many technologically relevant battery compounds. In other instances, instead of being diffusion-limited, electrodes may undergo charging limitation caused by the kinetics of the reduction reaction itself. Specific impedance models for reactionlimited mechanisms are summarized here and proved for relevant electrode compounds, in particular for conversion or alloying electrodes in which Li+ intake produces a full rearrangement of the lattice structure with significant atomic displacement

Application of a source-receptor model to determine source areas of pollen in Catalonia (NE Spain)

In this study we characterize the long-range transport of allergenic pollen to the North East of Spain. To this end, cluster analysis of back-trajectories and a source-receptor model was applied to a dataset of 10 years of airborne monitoring data corresponding to the period 2000-2009. The aim of the study is to examine and interpret the main transport routes and source areas affecting levels in Catalonia for a total of 20 pollen types. The cluster analysis of trajectories revealed that trajectories entering to the region by East France represent well the long distant transport of some taxa which are scarce in the Catalan territory or present only in limited areas (Ambrosia, Betula, Corylus and Fagus) together with other common in Catalonia (Fraxinus, Quercus deciduous type and Pistacia) showing agreement with the source areas obtained from the source-receptor methodology: Whereas, for taxa with local/regional sources (Artemisia, Castanea, total Poaceae, Plantago, total Polygonaceae, Olea, total Quercus and Quercus evergreen type) with high concentration levels associated to situations of recirculation over the Iberian Peninsula, the source-receptor model did not show reliable source regions.Peer Reviewe

El planeta de los Yunis. Situación fundamental de la función afín en 1º E.S.O.

Este trabajo fin de máster tiene como objetivo estudiar y valorar una propuesta de ingeniería didáctica basada en el aprendizaje del álgebra. El trabajo se estructura en dos partes. En la primera parte se realiza un estudio longitudinal del currículo y de los libros de texto en el tercer ciclo de Primaria, en ESO y en Bachillerato con relación al tema indicado. En la segunda parte se propone un proceso de estudio sobre el paso de la aritmética al álgebra, que se ha puesto en marcha en un aula de 1º ESO en el marco del Prácticum II del Máster. Los resultados extraídos de esta experimentación se fundamentan en una situación planteada en clase y en unas actividades realizadas a posteriori. El trabajo concluye con una síntesis, unas conclusiones y unas cuestiones abiertas.Máster Universitario en Profesorado de Educación Secundaria por la Universidad Pública de NavarraBigarren Hezkuntzako Irakasletzako Unibertsitate Masterra Nafarroako Unibertsitate Publikoa

Mujeres en una tierra en barbecho atravesada por la despoblación. Una mirada interseccional

El medio rural se ha visto inmerso en el fenómeno de éxodo especialmente durante el período comprendido entre 1950 y 1980, como consecuencia de la industrialización, intensificándose de manera notoria alrededor de 1960. Este proceso caracterizado por flujos de salidas dirigidas hacia núcleos poblacionales más habitados ha tenido un carácter selectivo, pues el colectivo femenino ha sido el más afectado. En este trabajo se analizan las causas que llevan a las mujeres a afianzarse en las ciudades y las repercusiones que esta situación tiene sobre su realidad y la del medio rural. De igual forma, a lo largo de la investigación se analizarán los diversos patrones de movilidad que desarrollan atendiendo a los perfiles ocupacionales, pues como se pone en evidencia en diversos estudios la mayor limitación para las mujeres es a nivel laboral. Por último, pero no por ello de menor relevancia, se analizarán las medidas reivindicativas que llevan a cabo para paliar el proceso de despoblación

Vicente Cervera Salinas, Borges en la Ciudad de los Inmortales

Reseña bibliográfica del libro de Vicente Cervera Salinas, Borges en la Ciudad de los Inmortales. Sevilla: Editorial Renacimiento, Colección Iluminaciones, 2014, 356 pp

Automatització i control SCADA de la màquina Tecnocable, per el procés de fabricació de cable elèctric

El present projecte final de carrera té l’objectiu d’automatitzar i controlar mitjançant un SCADA la línia 6 o Tecnocable de la fàbrica Cavigel que té Prysmian a Vilanova i la Geltrú. Aquesta màquina és l’encarregada de, mitjançant el procés d’extrusió, proporcionar l’aïllament a una mànega de cables. L’automatització realitzada s’ha aconseguit mitjançant un únic autòmat programable, o PLC, juntament amb els mòduls d’entrades i sortides de senyals necessaris. Per altra banda, i molt lligat amb l’automatització, s’ha realitzat un control SCADA com a interfícies operari-màquina. Finalment, en aquest projecte, s’han dimensionat les línies elèctriques així com les proteccions dels motors. També s’ha estudiat econòmicament la seva implantació

Are the Pyrenees a barrier for the transport of birch (Betula) pollen from Central Europe to the Iberian Peninsula?

This work provides a first assessment of the possible barrier effect of the Pyrenees on the atmospheric transport of airborne pollen from Europe to the North of the Iberian Peninsula. Aerobiological data recorded in three Spanish stations located at the eastern, central and western base of the Pyrenees in the period 2004–2014 have been used to identify the possible long range transport episodes of Betula pollen. The atmospheric transport routes and the origin regions have been established by means of trajectory analysis and a source receptor model. Betula pollen outbreaks were associated with the meteorological scenario characterized by the presence of a high-pressure system overm over Morocco and Southern Iberian Peninsula. France and Central Europe have been identified as the probable source areas of Betula pollen that arrives to Northern Spain. However, the specific source areas are mainly determined by the particular prevailing atmospheric circulation of each location. Finally, the Weather Research and Forecasting model highlighted the effect of the orography on the atmospheric transport patterns, showing paths through the western and easternmost lowlands for Vitoria-Gasteiz and Bellaterra respectively, and the direct impact of air flows over Vielha through the Garona valley.Peer ReviewedPreprin

Síntesis de péptidos multifuncionales que contienen un fluoróforo como sonda fluorescente

Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2016, Tutor: Ernesto Nicolás GalindoAlzheimer Disease (AD) is the most common cause of dementia in the elderly population. Symptoms of the disease are: difficulty in remembering newly learned information, mood and behaviour changes, memory loss, judgment alteration and difficulties in daily and usual activities. Today Alzheimer disease affects more than 30 million people worldwide and it is estimated that more than 100 million people will be affected by 2050 mainly because of the fast growth of the elderly population. Currently, it is generally accepted that Alzheimer disease originates from a process called amyloid cascade that occurs in the synaptic cleft, wherein A aggregation due to its union with Cu(II), is a key event. In this work, elaborated in collaboration with the group of Bioinorganic Chemistry led by Professor Patrick Gámez, the peptides with sequences Ac-His-Lys(Cm)-His-Lys-NH2 and Ac-His-Lys(4-DMN)-His-NH2 have been synthesized. These peptides encompass two amino acid derivatives containing two fluorescent probes: coumarin and 4-N,N-dimethylamino-1,8-naphthalimido. These peptide sequences will be studied as potential therapeutic agents due to its chelating properties of the Cu (II), as well as copper sensors for AD diagnosis.The amino acid derivatives have been synthesized in aqueous phase while peptides were synthesized in solid phase through the Fmoc strategy, using as polymer support Rink Amide resin. The peptides prepared were functionalized with an acetyl group in the N-terminus and a carboxamide group in the C-terminus. To obtain the desired synthetic sequence, Fmoc amino acids, protected at the N-terminus with the 9-fluorenylmethoxycarbonyl group (Fmoc), which is labile to piperidine, were used. For generating the amide bonds, N,N'-diisopropycarbodiimide (DIC) and Oxyma have been used. The cleavage of the peptide from the resin was performed under acidic conditions using trifluoroacetic acid (TFA) in the presence of triisopropylsilane (TIPS) as carbocation scavenger agent. The characterization of the products was carried out using different techniques such as 1H and 13C NMR, HPLC and HPLC-MS