RELATIVISTIC-DFT STUDY OF THE ELECTRONIC STRUCTURE, BONDING AND ENERGETIC OF THE [ReF8]־ AND [UF8]2- IONS

Indexación: Web of Science; Scielo.In this study we evaluated the importance of the relativistic effects (scalar and spin-orbit) on the description of the electronic structure, bonding and the energetic of the [ReF8]- and [UF8]2- ions. We described the bonding interaction between ligands and metal center using the energy decomposition analysis (EDA) proposed by Morokuma and Ziegler, in which it can be appreciated a strong ionic behavior for both ions since the electrostatic interaction energy (∆Ezlestat) is greater than the orbitalic interaction energy (∆EOrb). Furthermore, a qualitative analysis using the mapping of the electrostatic potential over the total electronic density evidence an increase of the ionic character, as well as, the polarization of the electronic density as U > Re. The electron localization function (ELF) corroborates the bonding analysis because of the lack of di-synaptic basins on the metal-ligand bonding region.http://ref.scielo.org/jcbd4

La Torre Cantonera del Migdia del recinto amurallado de Castellón de la Plana

La intervención arqueológica realizada con motivo de las obras de la “Red de Plataformas Reservadas al Transporte Público” en la Plaza Hernán Cortés de Castellón de la Plana, pusieron al descubierto una serie de elementos arquitectónicos, que han sido identificados como restos pertenecientes al sistema defensivo bajomedieval de la ciudad. Concretamente se corresponden con la “Torre Cantonera del Migdia”, punto en el que el recinto amurallado hacia esquina y giraba hacia el Este.The archaeological intervention that was carried out due to the construction of the “Web of Platforms Kept for the Public Transport” in Hernán Cortés Square in Castellón de la Plana, brought out a series of architectural elements which have been identified as remains belonging to thelate medieval defensive system of the city. They are specifically related to “Torre Cantonera del Mig Dia”, where the walls of the city made a corner and turned towards the east

CCCTC-binding factor locks premature IgH germline transcription and restrains class switch recombination

In response to antigenic stimulation B cells undergo class switch recombination (CSR) at the immunoglobulin heavy chain (IgH) to replace the primary IgM/IgD isotypes by IgG, IgE, or IgA. CSR is initiated by activation-induced cytidine deaminase (AID) through the deamination of cytosine residues at the switch (S) regions of IgH. B cell stimulation promotes germline transcription (GLT) of specific S regions, a necessary event prior to CSR because it facilitates AID access to S regions. Here, we show that CCCTC-binding factor (CTCF)-deficient mice are severely impaired in the generation of germinal center B cells and plasma cells after immunization in vivo, most likely due to impaired cell survival. Importantly, we find that CTCF-deficient B cells have an increased rate of CSR under various stimulation conditions in vitro. This effect is not secondary to altered cell proliferation or AID expression in CTCF-deficient cells. Instead, we find that CTCF-deficient B cells harbor an increased mutation frequency at switch regions, probably reflecting an increased accessibility of AID to IgH in the absence of CTCF. Moreover, CTCF deficiency triggers premature GLT of S regions in naïve B cells. Our results indicate that CTCF restricts CSR by enforcing GLT silencing and limiting AID access to IgH

Theoretical calculations of an osmium molecular switch

Indexación: Web of Science; Scielo.ABSTRACT We have investigated the molecular, electronic and optical properties of the [Os(tpy-py)2]2+ complex (tpy-py = 4'-(4-pyridyl)-2,2':6',2"-terpyridine) and its protonated derivative [Os(tpy-pyH)2]4+ through Density Functional Relativistic calculations including Scalar and Spin Orbit corrections. The molecular geometry of the parent complex is not strongly modified by the protonation at the basic nitrogen atoms of the pyridine moieties of the terpyridine ligands in the complex. On the other hand, the optical properties of these complexes can be controlled by a change in the chemical acid-base environment, converting them into suitable materials to act as molecular switches or pH sensor devices.http://ref.scielo.org/54hzc

On the reduction of 4-oxo-4h-benzopyran-3-carbaldehydes : global and local electrophilicity patterns

The theoretical global and local electrophilicity patterns of substituted and chelated 4-oxo-4H-benzopyran-3-carbaldehydes (formylchromones) have been evaluated using the electrophilicity index proposed by Parr et al [J. Am. Chem. Soc. 1999, 121, 1922]. The complexation of formylchromones with aluminum predicts a strong electrophilic character of these compounds against nucleophiles. Local response at the active sites may also be assessed in terms of a global contribution described by the global electrophilicity, and a local contribution described by the variations in electrophilic Fukui function at those sites. The highest local electrophilicity is found at the formyl group of the chelated formylchromones, in spite of that, the highest positive charge is located on the pyrone carbonyl group. This result is consistent with the experimental observed reactivity displayed by 4-oxo-4H-benzopyran-3-carbaldehydes in the presence of 2-propanol and alumina

Spin-orbit and solvent effects in the luminescent [re6q8(ncs)6]4-, q=s, se, te clusters: molecular sensors and molecular devices

Indexación: ScieloRelativistic time-dependent density functional (TDDFT) calculations including spin orbit interactions via the zero order regular approximation (ZORA) and solvent effects using the COSMO model were carried out on the [Re6Q8(NCS)6]4- , (Q = S, Se, Te) clusters. These calculations indicate that the lowest energy allowed electronic transitions are characterized by being of LMCT type. The calculated absorption maximum tends to shift to longer wavelengths as the face-capping chalcogenide ligand becomes heavier. Thus our calculations predict that the [Re6Te8(NCS)6]4- cluster might be also luminescent. Due to the unusual properties exhibited by these and other isoelectronic and isostructural hexarhenium (III) chalcogenide clusters, hexamolybdenum halide clusters and hexatungsten halide clusters, we propose here the design of nanodevices, such as, molecular sensors and molecular nanocells for molecular electronics.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072010000100010&nrm=is

La Peguesa: un nuevo conjunto de grabados rupestres en la comarca de Els Ports (Castellón)

El conjunto de grabados rupestres de la Peguesa, se localiza en el T.M. de Morella, junto a la actual carretera que une las poblaciones de Morella y Cinctorres. Al mismo tiempo esta vía de tránsito comunica las cuencas de dos de los principales ríos de la comarca, el Bergantes y el Calders. Los grabados se distribuyen sobre un pequeño afloramiento de roca arenisca que apenas sobresale del campo de cultivo donde se localiza el conjunto. Los motivos representados muestran una interesante combinación de motivos figurativos (antropomorfos, cruciformes, ramiformes, etc...), junto con motivos abstractos (reticulado, cazoletas, cúpulas, trazos, etc...) y han sido realizados con la técnica del picado, aunque existen diferencias en dicha técnica de ejecución.The open-air engravings site of la Peguesa is located into Morella Township, close to the road between Morella and Cinctorres. This actual road takes profit of a natural passage between the main rivers of the region, Bergantes and Calders. The engravins are on a sandstone outcrop, located in discrete way in the middle of a field. The site displays an interesting combination of figurative motifs (anthropomorphus, cruciforms, ramiforms, etc.), together with another abstracts motifs (reticulated and cup-marks). The making technique was chipping to great part of motifs but other ones have been made with abrasion

Confronted monuments: new roles for heritage in the face of social disagreements

The attacks on monuments —street art, mutilations, being brought down— that have been seen around the world recently, cannot go unnoticed by heritage academics. It is a phenomenon that heralds the obsolescence of ideas and theories adopted so far on heritage and its conservation. Throughout this work, reflections are made about heritage as cultural heritage, explaining how commemorative monuments differ from historical monuments, a topic that comes under the limelight when talking about museification and petrification of heritage. To give context to this phenomenon, three attacks on monuments are addressed the march of November 8th, 2018 in Santiago de Chile, when people brought down statues in the US and England within the Black Lives Matter movement and the #NoMeCuidanMeViolan movement, in Mexico. The reflection considers the motivations behind these actions against heritage, the reactions of hegemonic groups and, more than anything, the resignifications and redefinitions that are taking place or could take place, as a result of all this, about cultural heritage.La agresión a monumentos —pintas, mutilaciones, derribos—, que se han visto recientemente en todo el mundo, no puede pasar desapercibida para los estudiosos del patrimonio. Es un fenómeno que anuncia la obsolescencia de ideas y teorías adoptadas hasta ahora sobre el patrimonio y su conservación. A lo largo del trabajo se reflexiona en torno al patrimonio como herencia cultural, y se explica cómo los monumentos conmemorativos difieren de los monumentos históricos, un asunto que adquiere centralidad cuando se habla de museificación y petrificación del patrimonio. Para situar este fenómeno en la realidad, se abordan tres situaciones de asalto a monumentos —la marcha del 8 de noviembre de 2018 en Santiago de Chile, el derribo de estatuas en EUA e Inglaterra dentro del movimiento black lives matter y el movimiento #NoMeCuidanMeViolan en México—. La reflexión es en torno a las motivaciones que llevan a estas actuaciones sobre el patrimonio, a las reacciones que se generan de parte de los grupos hegemónicos y, más que nada, en cuanto a las resignificaciones y redefiniciones que se van dando o pudieran darse, a partir de todo esto, sobre el patrimonio cultural.O ataque a monumentos —pinturas, mutilações, demolições— recentemente vistos em todo o mundo, não pode passar despercebido aos estudiosos do patrimônio. É um fenômeno que anuncia a obsolescência das ideias e teorias até então adotadas sobre o patrimônio e sua conservação. Ao longo da obra, é refletida sobre o patrimônio como patrimônio cultural, e é explicado como os monumentos comemorativos se diferenciam dos monumentos históricos, questão que adquire centralidade quando se fala em museificação e petrificação do patrimônio. Para colocar este fenômeno em realidade, três situações de assalto a monumentos são abordadas —a marcha de 8 de novembro de 2018 em Santiago do Chile, a demolição de estátuas nos Estados Unidos e na Inglaterra dentro do movimento black lives matter e o movimento #NoMeCuidanMeViolan no México— o último é tratado de forma mais extensa. A reflexão gira em torno das motivações que levam a essas ações sobre o patrimônio, das reações que se geram por parte dos grupos hegemônicos e, mais do que tudo, quanto às ressignificações e redefinições que estão ocorrendo ou que poderiam ser atribuídas a partir de tudo isso no patrimônio cultural