Novel Charge-Transfer Materials via Cocrystallization of Planar Aromatic Donors and Spherical Polyoxometalate Acceptors

Spherical polyoxometalates (POMs) such as M6O192- and SiM12O404- (with M = Mo or W) and planar arene donors (anthracenes and pyrenes) can be cocrystallized (despite their structural incompatibility) by attaching a cationic “anchor” onto the arene which then clings to the POM anion by Coulombic forces. As a result, novel charge-transfer (CT) salts are prepared from arene donors and Lindqvist-type [M6O19]2- and Keggin-type [SiM12O40]4- acceptors with overall 2:1 and 4:1 stoichiometry, respectively. The CT character of the dark-colored (yellow to red) crystalline materials is confirmed by the linear Mulliken correlation between the CT transition energies and the reduction potentials of the POM acceptors, as well as by the transient (diffuse reflectance) absorption spectra (upon picosecond laser excitation) of anthracene or pyrene cation radicals (in monomeric and π-dimeric forms). X-ray crystallographic studies reveal a unique “dimeric” arrangement of the cofacially oriented arene couples which show contact points with the oxygen surface of the POMs that vary with distance, depending on the POM/arene combination. Moreover, the combination of X-ray crystallographic and spectroscopic techniques results in the observation of a logical structure/property relationshipthe shorter the distance between the POM surface and the arene nucleus, the darker is the color of the CT crystal and the faster is the decay of the laser-excited charge-transfer state (due to back-electron transfer)

The economic diplomacy of a small state : the case of Namibia

This study is about the economic diplomacy of Namibia, as a small state, for the period 1990 – 2015. Liberalism, as a theory of International Relations (IR) studies, is the adopted analytical framework. Namibia’s economic diplomacy is anchored in the foreign policy principles enshrined in article 96 of her constitution, which advocate, inter alia, the maintenance of mutual beneficial relations. Namibia, further enacted laws and adopted policies that serve as domestic instruments of economic diplomacy. The stakeholders in Namibia’s economic diplomacy include both state and non-state actors. The study adopts a population of 8 million as the benchmark for small states, plus one of the following characteristics of small states: small size of the territory; low economy and the perception by the government leaders and nationals. Namibia’s bilateral economic diplomacy covers over one hundred countries. Her major trade partners, in terms of export trade and inward investments are Angola, Canada, China, Germany, The Netherlands, Spain, South Africa, Switzerland, The United Kingdom and the United States. Bilateral economic diplomacy is further pursued through the Export Processing Zone (EPZ) exports. The Namibian Government pursues multilateral economic diplomacy with the European Union, as part of the Africa Caribbean Pacific states and with regional and international economic and trade organisations such as the Southern Africa Customs Union, the Southern Africa Development Community, the United Nations Conference in Trade and Development and the World Trade Organisation. Namibia also adopts conference diplomacy as a form of multilateral economic diplomacy. The study makes an epistemological contribution to the study of IR, that the world is constructed under the hierarchical order that constrains power-based relations and minimises conflicts in international trade. A minimal trend of pursuing interests is, however, observed. The study further makes an ontological contribution to the study of IR, that the behaviour of state and non-state actors are inclined to cooperation on the continuum of conflict and cooperation. The study concludes that, contrary to the assumptions in small states literature, that small states have limitations of capacity and play an insignificant role in multilateralism, Namibia has skilled negotiators who have led negotiations in regional and international organisations.Political SciencesD. Litt. et Phil. (International Politics

Dissolution of CaCO3 in the present and glacial ocean: A comparison of the effects of different dissolution parameterizations

The production of the calcium carbonate minerals calcite and aragonite in the ocean is primarily done by different pelagic calcifying organisms: coccolithophorids, foraminifera and pteropods. The contribution of corals to the production of CACO3 is comparatively small. The surface ocean is supersaturated with respect to the two minerals forms of CACO3: aragonite and calcite, while the deep ocean is undersaturated. Most of these calcium carbonate minerals produced near the surface ocean sink through the water column and mainly dissolve in the deep ocean below the saturation horizon where the solubility product of the minerals increases due to increased pressure. CaCO3 formation in the surface ocean and dissolution in the deeper ocean both affect dissolved inorganic carbon and total alkalinity and also the oceanic pCO2. In this study, a global biogeochemical model (REcoM) is used to analyze the production and dissolution of CaCO3 for the Last Glacial Maximum (LGM) and present day with two different set up of dissolution rate: one is that the dissolution rate of CaCO3 is assumed constant when it sinks through the water column (λ does not depend on Ω ), in other λ has been made depend on Ω. In REcoM, biogenic CaCO3 production is restricted to phytoplankton. In comparison with observation, model simulation with uniform dissolution does a good job at reproducing the global patterns of DIC, alkalinity and Ω although some regional differences remain: too high DIC concentrations in between 800 m to 1200 m ocean depth, high alkalinity concentration in the depth between 1200 m to 2000 m and higher Ω in the Atlantic Ocean and the Indian Ocean value. In this study, it is tested that whether changes in the parameterization of the CaCO3 dissolution rate in the model can improve the distribution. Making the dissolution depend on Ω leads to a much improved global oceanic distribution of DIC, alkalinity and Ω. Furthermore, LGM model simulation reproduce the ocean of low temperature, salty and high in alkalinitry and DIC concentration than the present day [Buchanan et al., 2016b, Vo ̈lker and Ko ̈hler, 2013, Zhang et al., 2013]. The overall LGM ocean is high in calcium carbonate saturation than the present day because of higher [CO2−] concentration

New Samarium(III), Gadolinium(III), and Dysprosium(III) Complexes of Coumarin-3-Carboxylic Acid as Antiproliferative Agents

New complexes of samarium(III), gadolinium(III), and dysprosium(III) with coumarin-3-carboxylic acid (HCCA) were prepared by the reaction of the ligand with respective metal nitrates in ethanol. The structures of the final complexes were determined by means of physicochemical data, elemental analysis, IR and Raman spectra. The metal-ligand binding mode in the new Ln(III) complexes of coumarin-3-carboxylic acid was elucidated. The vibrational study gave evidence for bidentate coordination of CCA− to Ln(III) ions through the carbonylic oxygen and the carboxylic oxygen atoms. The complexes were tested for antiproliferative activitiy on the chronic myeloid leukemia-derived K-562, overexpressing the BCR-ABL fusion protein. Cytotoxicity towards tumor cells was determined for a broad concentration range. The samarium salt exerted a very weak antiproliferative effect on these cells. This is in contrast to the lanthanide complexes, especially samarium complex, which exhibited potent antiproliferative activity. The present study confirms our previous observations that the lanthanide complexes of coumarins exhibit antiproliferative activity towards K-562 cell line

Relevancia del tutor de las prácticas clínicas

El aprendizaje de las habilidades clínicas es uno de los aspectos más primordiales en la formación de los estudiantes de enfermería. Tales habilidades requieren no sólo destreza en su realización, sino también integración de los conocimientos inherentes a los procedimientos a realizar, sin olvidar la calidad humana que deben incorporar, ya que normalmente se realizan en o con las personas que presentan problemas reales o potenciales de salud

Análisis de crash-box con materiales compuestos

El presente trabajo se ha desarrollado en el seno de la empresa Solute S.L. durante un periodo en cual el autor del mismo trabajaba en la citada empresa, dentro del departamento de análisis mecánico y estructural. Solute S.L. se dedica a la simulación numérica en sectores de la ingeniería, tales como aeronáutica, civil, energética, ferroviaria y automotriz. Entre los estudios más habituales se encuentran los ensayos de impacto de vehículos, análisis estáticos, análisis dinámico y de fatiga mediante técnicas de elementos finitos. Así mismo Solute S.L. desarrolla y comercializa un software propio de estudio de recurso eólic

Algunas reflexiones sobre la formación en la universidad

Algunos de los temas que constantemente, de una forma u otra, están saliendo en los periódicos estos últimos meses hacen referencia a la formación universitaria. Y lo hacen por una parte desde la perspectiva de si las futuras titulaciones de grado, con el enfoque del Espacio Europeo de Educación Superior, se adaptarán realmente a las necesidades del mercado laboral. Y por otra está la discusión sobre los aspectos referidos al propio gobierno de las universidades. Especialmente si deberían tener más intervención por parte de la sociedad, en especial por parte de los ámbitos de la empresa, de la administración y de la política, para conferirle un "enfoque de utilitarismo"

Contexto histórico-teatral ruso e influencias tempranas de Stanislavsky

El presente trabajo es el resultado de una investigación acerca de las primeras influencias a partir de las cuales se concibieron el imaginario, el sistema pedagógico y la técnica interpretativa de Constantin Sergeyevich Stanislavsky (1863-1938). Las ideas extraídas del estudio se presentan a través de tres bloques principales: el contexto histórico-teatral en Rusia; la infancia y juventud de Stanislavsky; y las influencias del romanticismo y el realismo ruso hasta la creación del MAT en 1898El present treball és el resultat d'una investigació sobre les primeres influències a partir de les quals es van concebre l'imaginari, el sistema pedagògic i la tècnica interpretativa de Constantin Sergeyevich Stanislavsky (1863-1938). Les idees extretes de l'estudi es presenten a través de tres blocs principals: el context històric-teatral a Rússia; la infantesa i joventut de Stanislavsky; i les influències del romanticisme i el realisme rus fins a la creació del MAT el 1898

Turnos de 7 horas versus 12 horas en enfermería intensiva: vivir a contratiempo

Resumen Los turnos de trabajo tienen repercusión sobre el bienestar de los profesionales sanitarios influyendo en su calidad de vida. El objetivo principal de este estudio es describir las consecuencias que tiene el turno de trabajo diurno de 12 h respecto al de 7 h en los profesionales de enfermería que trabajan en Unidades de Cuidados Intensivos. Se trata así de un estudio descriptivo transversal en 2 hospitales de tercer nivel de Barcelona: Hospital Clínico y Hospital Vall d"Hebron (turnos de 7 h y 12 h respectivamente). La recogida de datos se ha realizado mediante cuestionario ad hoc de 29 preguntas cerradas, anónimo y autoadministrado, basado en 2 escalas: Standard Shiftwork Index y Shiftwork locus of control. Dichos datos fueron procesados a través del programa SPSS V.18.0. De las 85 encuestas realizadas 52 fueron válidas: 22 en el Hospital Clínico de Barcelona y 30 en el Hospital Vall d"Hebron. Cabe destacar que los profesionales encuestados que trabajan en turno de 12 h expresan niveles superiores de conciliación laboral y personal, concretamente en tiempo de ocio a disfrutar (× 2: 10,635; p = 0,031) y tiempo de dedicación familia-amigos, así como niveles más bajos de percepción de fatiga. No se han encontrado diferencias entre el tipo de turno y facilidad de desarrollo del trabajo profesional, a pesar de que el turno de 12 h presenta niveles más altos