877 research outputs found
PPh(2-C6H4S)(2) as a pincer ligand in nickel(II) and palladium(II) complexes - X-ray structure of [Ni{PPh(C6H4S)(2)}(PPh2Me)], [Pd-2(mu-dppe){PPh(C6H4S)(2)}(2)] and [Ni{PPh(C6H4S)(2)}](2)
No full textThe phosphanylthiol PPh(2-C6H4SH)(2) reacts with the Ni-II and Pd-II complexes [MCl2L2] in the presence of NaOEt to give the mononuclear derivatives [M{PPh(C6H4S)(2)}L] [M = Ni, L = PPh3 (1), PPh2Me (2); M = Pd, L = PPh3 (3)]. The analogous reaction starting with complexes containing bidentate ligands [MX2(L-L)] produces different results depending on the ligand used. The complexes [M{PPh(C6H4S)(2)}(dppm)] [M = Ni (4), Pd (5)], with an unligated phosphorus atom in the diphosphdne are obtained with bis(diphenylphosphanyl)methane (dppm), while the dinuclear complexes [M-2(mu-dppe){PPh(C6H4S)(2)}] [M = Ni (6), Pd (7)] are isolated in the case of 1,2-bis(diphenylphosphanyl)ethane (dppe). With 1,10-phendtithroline (phen), the complexes [M{PPh(C6H4S)(2)}(phen)] [M = Ni (8), Pd (9)] are obtained, but when 2,2'-bipyridine is used the dinuclear compounds [M{PPh(C6H4S)(2)}](2) [M = Ni (10), Pd (11)] are isolated instead. Complexes 10 and 11, which Can be obtained starting from NiCl2 or [PdCl2(NCPh)(2)] respectively, afford complexes 1-7 when treated with the respective phosphanes in the appropriate stoichiometries, The structures of 2, 7 and 10 have been confirmed by X-ray analysis
Novel gold(I) thiolate derivatives synergistic with 5-fluorouracil as potential selective anticancer agents in colon cancer
No full textNew gold(I) thiolate complexes have been synthesized and characterized, and their physicochemical properties and anticancer activity have been tested. The coordination of PTA derivatives provides optimal hydrophilicity/lipophilicity properties to the complexes, which present high solution stability. Moreover, the complexes show a high anticancer activity against Caco-2 cells, comparable to that of auranofin, and a very low cytotoxic activity against enterocyte-like differentiated cells. Their activity has been shown to produce cell death by apoptosis and arrest of the cell cycle because of interaction with the reductase enzymes and consequent reactive oxygen species production. Some of these new complexes are also able to decrease the necessary dose of 5-fluorouracil, a drug used for the treatment of colon cancer, by a synergistic mechanism.E.C. and M.J.R.-Y. thank the Ministerio de Economia y Competitividad (Grants CTQ2016-75816-C2-1-P and SAF2016-75441-R, respectively) and DGA (Grants E104 and A-32) for financial support.Peer reviewe
Compuestos heterometálicos de iones de capa cerrada con ligandos macrocíclicos
No full textEl presente trabajo está dedicado a la síntesis y caracterización de nuevos complejos heterometálicos de oro(I) con otros metales de capa cerrada, coo cobre(I), plata(I) o talio(I). La reactividad de los precursores heterometálicos de Au(I)/Cu(I), Au(I)/Ag(I) y Au(I)/Tl(I) frente a ligandos macrocíclicos de diferente naturaleza y capacidad coordinativa ([9]aneS3, [14]aneS4, [24]aneS8, [12]aneS3N-CH2Quinolina y [12]aneS2N2-(CH2Quiniolina)2) da lugar a la obtención de nuevos derivados que, en la mayoría de los casos, presentan interacciones metalofílicas. La realización de estudios experimentales de forma conjunta con estudios teóricos ha permitido analizar la relación entre las propiedades ópticas que presentan estos nuevos derivados y su estrucutra. Además, se han llevado a cabo estudios de cristalografía de alta presión sobre dos isómeros de estequiometría [{Au(C6Cl5)2{Ag([9]aneS3)}]2 analizando cómo los cambios en la interacción aurofílica provocados por el aumento de presión modifican las propiedades luminiscentes
Tetrathiafulvalene-functionalized phosphine as a coordinating ligand. X-Ray structures of (PPh2)(4) TTF and [(AuCl)(4){(PPh2)(4)TTF}]
No full textThe phosphine (PPh2)(4) TTF (P4) (1) reacts with the gold() complexes [AuX( tht)] (X = Cl, C6F5; tht = tetrahydrothiophene) or [Au(Mes)(AsPh3)] (Mes = 2,4,6-Me3C6H2) to give tetranuclear derivatives [( AuX)(4)P4] (X = Cl, 2; C6F5, 3; Mes, 4). The analogous reaction starting with [Au(Trip)(AsPh3)] (Trip = 2,4,6-Pr-i(3) C6H2) provides the dinuclear derivative [(AuTrip)(2) P4] (5). When the phosphine P4 reacts with [Cu( MeCN)(4)]PF6, AgCF3SO3 or [Au(tht)(2)]CF3SO3 in a 2: 1 molar ratio, complexes [M(P4)(2)]A (A = PF6, M = Cu, 6; A = CF3SO3, M = Ag, 7, Au, 8) are obtained, or {[M2P4]( CF3SO3)(2)}(n) (M = Ag, 9; Au, 10) when 1: 1 molar ratios are used instead. Visible- ultraviolet and electrochemical studies of the new complexes are reported. Two, reversible one-electron oxidations to the mono- and di-cation occur in complexes 2-10 at more positive potentials than the two reversible oxidations exhibited by the free P4 (1) ligand. The structures of 1 and 2 have been confirmed by X-ray analysis
Insight into the potential application of polyphenol-rich dietary intervention in degenerative disease management
No full textIn recent times, a great number of plants have been studied in order to identify new components with nutraceutical properties, among which are polyphenols. Dietary polyphenols represent a large group of bioactive molecules widely found in the food of plant origin and they have been found able to prevent the onset and progression of degenerative diseases, and to reduce and control their symptoms. These health protective effects have been mainly related to their antioxidant and anti-inflammatory properties. However, it must be considered that the application of isolated polyphenols as nutraceuticals is quite limited due to their poor systemic distribution and relative bioavailability. The present review highlights the potential effect of dietary intervention with polyphenol-rich food and plant extracts in patients with cancer, diabetes and neurodegenerative, autoimmune, cardiovascular and ophthalmic diseases, as well as the possible molecular mechanisms of action suggested in numerous studies with animal models.The authors acknowledge The Ministerio de Economia y Competitividad (CTQ2016-75816-C2-1-P and SAF2016-75441-R), DGA (B16-R17and E104), CIBERobn (CB06/03/1012, Carlos III) and European Grant Interreg/SUDOE (Redvalue, SOE/PI/E0123) for financial support.Peer reviewe
Propuesta de creación de un Centro de Investigaciones Agrícolas en la “ETAR Mesa Cerrada” Timotes estado Mérida
No full textThe objective of this paper is to promote the creation of a Center for Agricultural Research at the Escuela Técnica Agropecuaria Robinsoniana (ETAR) “Mesa Cerrada” (Robinsonian Technical and Farming School “Mesa Cerrada”) located in Timotes, Mérida, Venezuela. This investigation was conducted according to the participatory action research, due to the interest in searching for social transformations. This results in strengthening the bases for a new society by means of the recovery of indigenous crops and other farming activities with the purpose of improving working conditions and productive crops. This work is intended to be useful not only for Timotes population, but also to Venezuelan education.El objetivo de este artículo es promover la creación de un Centro de Investigaciones Agrícolas en la Escuela Técnica Agropecuaria Robinsoniana “Mesa Cerrada”, Timotes estado Mérida. Se trata de una investigación-acción de tipo participativa, la cual responde a la búsqueda de transformaciones sociales, lo que permitirá el fortalecimiento de las bases de una nueva sociedad, en un contexto de recuperación de cultivos autóctonos y actividades agrícolas que serán realizadas por la comunidad educativa, con el propósito de contribuir a mejorar las condiciones de trabajo del agricultor y facilitarles las herramientas necesarias para obtener altas cosechas productivas. Por lo tanto, este trabajo será de gran ayuda no sólo a la población de Timotes, sino también al mejoramiento de la educación en Venezuela
Propuesta de un modelo estratégico administrativo-financiero como herramienta para mejorar la gestión de los inmuebles de la banca cerrada recibidos por el Banco Central del Ecuador producto de la crisis bancaria de 1999 en el Ecuador
No full textLa presente investigación recopila información de los procesos de la Dirección de Administración de Activos y Fideicomisos del Proyecto de Inversión Pública “Recepción, Validación, Administración y Liquidación de la Banca Cerrada”, la misma que se complementa con el análisis de los recursos invertidos para este efecto. Con la información recolectada se elaboró un modelo de cálculo que permite cuantificar el número de procesos, bienes inmuebles vendidos y tiempos involucrados. El modelo estratégico administrativo- financiero propuesto toma como marco referencial la Ley Orgánica para el cierre de la crisis bancaria de 1999, y proporciona una herramienta y procedimientos que permiten mejorar la gestión de los inmuebles de la banca cerrada recibidos por el Banco Central del Ecuador, en función a parámetros de eficiencia y eficacia, puesto que logra la reducción de tiempos y costos. Esta propuesta genera una reingeniería de procesos los cuales evaluados financiera y operativamente contribuyen a un mejor desarrollo de uno de los objetivos del Banco Central del Ecuador, que es devolver los depósitos a los perjudicados de la banca cerrada, en razón que tiene implicaciones económicas y sociales de un problema que ha llevado más de 15 años en ser solucionado.Capítulo I. El problema de la investigación. Capítulo II. Marco teórico. Capítulo III. Metodología. Capítulo IV. Análisis e interpretación de resultados. Capítulo V. Conclusiones y recomendaciones. Capítulo VI. La propuesta. Bibliografía
Un sueño monadológico de José Donoso: “La puerta cerrada”
No full textThe author suggests a reading for the short story or “nouvelle” by José Donoso, “La puerta cerrada” (“The closed door”), from a poetic-philosophical perspective. The ethos defi ning the main character, Sebastián Rengifo, is characterised around the concept of “monad” coined by G. W. Leibnitz. This impenetrable spiritual essence, his lunar dimension, his impossible communication with his social and familiar milieu bounds him with the physical-metaphysical notion of “Monadology”. This is so due to his will to look in the magma of his dreams in order to recover a universal light. The process narrated by Donoso links the plot of his narrative with the Romantic tradition of the search of the “blue flower” that always comes in dreams, that is Sebastián´s case seals his wake with that closed door determining his condition as a monad.El autor propone una lectura del relato o “nouvelle” de José Donoso, “La puerta cerrada”, desde una perspectiva poético-fi losófi ca. El “ethos” que singulariza la fi gura del protagonista, Sebastián Rengifo, es caracterizado a partir del concepto de “mónada” acuñado por G. W. Leibnitz. Su esencia espiritual impenetrable, su dimensión lunar, su imposible comunicación con el medio social y familiar favorecen la vinculación del personaje con la noción físico-metafísica de la “Monadología”, en virtud de su voluntad intransferible para indagar en el magma de sus sueños donde rescatar una luz de entraña universal. El proceso que narra Donoso entronca el argumento de la obra con la tradición romántica de la búsqueda de la “flor azul” que surge en los sueños, y que en el caso de Sebastián sella su despertar con esa puerta cerrada que determina su condición de “mónada”
CARTAS PARA TRANSFIGURAR O TEMPO: O ROMANCE EPISTOLAR EM NATALIA GINZBURG E ELENA PONIATOWSKA
No full textEsse artigo desenvolve uma interpretação dos romances Querido Diego, sua Quiela, de Elena Poniatowska, e Caro Michele, de Natalia Ginzburg, que busca valorizar a forma singular de cada obra e o estilo das autoras para entender as potencialidades da forma epistolar em romances de ficção e as diferentes estratégias que podem ser empregadas para lidar com a construção de personagens e seus sentimentos, por meio de narrativas que lidam com o tom intimista e pessoal. Ao invés de partir de conceitos prévios, buscamos por meio de uma leitura cerrada entender como os romances exploram de maneiras diferentes as possibilidades da forma epistolar e como as estratégias de narração adotadas contribuem para uma reflexão e uma percepção a respeito do tempo através do trabalho da linguagem. Seja enredando o leitor em uma história de amor que possui referentes históricos ou urdindo um conjunto de relações entre personagens, temos diferentes formas de narrar que apontam para o silêncio e a ausência como elementos incontornáveis
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