Synthesis and characterization of chiral germanium compounds for asymmetric hydrogermylation of organic compounds

Oligogermanes have long been studied and analyzed due to their innate ability to undergo o-delocalization along the Ge-Ge backbone. Due to this property, oligogermanes can exhibit unique optical and electrical properties, along with a tunable band gap that is dependent on their size, structure, and substituents. The focus of this dissertation will be around the synthesis of a new class of trigermanes and tetragermanes.The trigermanes ButMe2GeGePh2GeMe2But and PhMe2GeGePh2GeMe2Ph and the tetragermanes Et3Ge(GePh2)2GeEt3 and Bun3Ge(GePh2)2GeBun3 were synthesized via the hydrogermolysis reaction. These species were characterized by UV/visible spectroscopy, cyclic voltammetry, and differential pulse voltammetry. The properties of the two trigermanes were also compared with those of Bun3GeGePh2GeBun3, and the UV/visible absorption maxima of these three trigermanes fall in the narrow range of 246 - 249 nm while their oxidation potentials differ by 233 mV. Both ButMe2GeGePh2GeMe2But and Bun3GeGePh2GeBun3 exhibit two irreversible oxidation waves in their CVs and DPVs. Similarly, the absorption maxima for the two tetragermanes are similar and their oxidation potentials differ by only 58 mV. The CV and DPV of Et3Ge(GePh2)2GeEt3 exhibits three irreversible oxidation waves while that of Bun3Ge(GePh2)2GeBun3 contains only one. This dissertation will focus on gaining an understanding of the electronic properties, stability, and decomposition of these oligogermane catenates when oxidized using cyclic and differential pulse voltammetry studies.This dissertation will also focus on synthesizing and characterizing germanium aryloxide compounds for hydrogermylation applications. Through the use of chiral auxiliaries and polyfunctional phenols, a germanium (II) and germanium (IV) species can be readily synthesized. The addition of a halide and an organic substituent can be added via an oxidative addition to the germanium (II) center, followed by a reduction to form a germanium hydride species. For the germanium (IV) center, a C2-symmetric chiral germanium halide species can be formed readily, followed by a reduction to form a chiral germanium hydride for hydrogenation of other compounds. Further functionality studies on the chiral germanium (IV) species have been performed as this compound readily undergoes the formation of a chiral germylium species when introduced to AlCl3. Such germylium species are rare, and with the use of a chiral auxiliary ligand, this compound to the best of our knowledge has yet to be reported

Insurgencia popular, oligarquía regional y estado en el Ecuador liberal (1895-1925): la Huelga General de Guayaquil, 1922

Not available.Los acontecimientos de Guayaquil, en noviembre de 1922, constituyeron la expresión social más relevante de la crisis económica que, desde la I Guerra Mundial, afectaba al país. Los violentos sucesos supusieron el inicio de un cambio sustantivo en la correlación de las fuerzas sociales y políticas del Ecuador de los años 20; anunciaron el debilitamiento e inmediato final del régimen liberal que, sostenido por la oligarquía cacaotera de la costa ecuatoriana, se había mantenido en el poder desde 1895, a la par que significaron el comienzo de la presencia efectiva de nuevos actores sociales en la escena nacional. Sin embargo, por sus dimensiones de sacrificio popular y rebeldía ante el Estado, los sucesos han venido representando un auténtico hito fundacional para el movimiento obrero ecuatoriano, motivo que ha propiciado que esta perspectiva haya sido la predominante en la historiografía sobre el tema. En el presente artículo se ofrece una visión que, rebasando los márgenes estrictamente obreros de la cuestión, expone toda la complejidad de este hecho social, frecuentemente obviada, a través de las diversas interrelaciones de los diferentes sectores sociopolíticos que en él participaron

Magnetic graphene molecularly imprinted polypyrrole polymer (MGO@MIPy) for electrochemical sensing of malondialdehyde in serum samples

A modified screen-printed carbon electrode (SPCE) has been designed and fabricated for the determination of malondialdehyde (MDA), an important biomarker of oxidative stress. Magnetic graphene oxide (MGO) was synthesized and coated by a molecularly imprinted polypyrrole (MIPy) for the preparation of a novel hybrid nanomaterial (MGO@MIPy). The nanocomposite has been characterized using different spectroscopic and imaging techniques. The coupling of MIPy with MGO allows the exploitation of the magnetic properties of the material for separation, preconcentration and manipulation of analyte which is selectively captured onto the MIPy surface of the nanocomposite. Besides, the derivatization of MDA with diaminonaphtalene (DAN) was carried out, resulting in a more electroactive molecule (MDA-DAN). MDA-DAN was used as template in the synthesis of MIPy. SPCEs were employed to monitor the differential pulse voltammetry (DVP) levels of the material, which is related to the amount of the captured analyte. Under optimum conditions, the nanocomposite-based sensing system has proved to be suitable for the monitoring of MDA, presenting a wide linear range (0.01–100 µM), high sensitivity (experimental LOQ = 0.01 µM) and precision (RSD = 4%). For validation purposes, three chicken serum samples were analysed by external calibration, obtaining recoveries values close to 100% for all the spiked tests. Finally, the developed electrochemical sensor demonstrated to be adequate for bioanalytical application, presenting an excellent analytical performance for the routine monitoring of MDA in serum samples.The Spanish Ministry of Science and Innovation, JJCC Castilla-La Mancha and Junta de Andalucía are gratefully acknowledged for funding this work with Fellowship FPU18/05371, and Grants PID2019-104381 GB-I00, JCCM SBPLY/17/180501/000262, and UMA18FEDERJA060, respectively. Funding for open access charge: Universidad de Málaga /CBUA

Topographic characterisation of dental implants for commercial use

To characterize the surface topography of several dental implants for commercial use. Dental implants analyzed were Certain (Biomet 3i), Tissue Level (Straumann), Interna (BTI), MG-InHex (MozoGrau), SPI (Alphabio) and Hikelt (Bioner). Surface topography was ascertained using a confocal microscope with white light. Roughness parameters obtained were: Ra, Rq, Rv, Rp, Rt, Rsk and Rku. The results were analysed using single-factor ANOVA and Student-Neuman-Keuls(p<0.05) tests. Certain and Hikelt obtained the highest Ra and Rq scores, followed by Tissue Level. Interna and SPI obtained lower scores, and MG-InHex obtained the lowest score. Rv scores followed the same trend. Certain obtained the highest Rp score, followed by SPI and Hikelt, then Interna and Tissue Level. MG-InHex obtained the lowest scores. Certain obtained the highest Rt score, followed by Interna and Hikelt, then SPI and Tissue Level. The lowest scores were for MG-InHex. Rsk was negative (punctured surface) in the MG-InHex, SPI and Tissue Level systems, and positive (pointed surface) in the other systems. Rku was higher than 3 (Leptokurtic) in Tissue Level, Interna, MG-InHex and SPI, and lower than 3 (Platykurtic) in Certain and Hikelt. The type of implant determines surface topography, and there are differences in the roughness parameters of the various makes of implants for clinical use

Ocio y acción sociocultural para el desarrollo de la ciudadanía.

This communication will serve to share part of the state of the project I + D + i: ‘Leisure, sociocultural action and social cohesion’. Specifically the most relevant findings on the main actions that, in leisure time, favor the development of citizens generating social cohesion shall be presented, taking into account: 1. The theoretical contributions related to. 2. Social and educational policies –at local, national and international levels– that have been able to provide evidence of its positive impact on the development of citizenship. 3. Projects of social, educational intervention and/ or cultural nature, which also stand out for their contribution of evidence of positive impact on the population they target. Finally, provide the discussion about what kind of professional skills, which should influence from training to facilitate teams to promote successful actions in the field of social intervention.Esta comunicación servirá para compartir parte del estado de la cuestión del proyecto I+D+i: ‘Ocio, acción sociocultural y cohesión social’. En concreto se presentarán los hallazgos más relevantes sobre las principales acciones que, en el tiempo de ocio, favorecen el desarrollo de una ciudadanía generadora de cohesión social teniendo en cuenta: 1. Las aportaciones teóricas que lo abordan. 2. Políticas sociales y educativas a nivel local, nacional e internacional que han podido aportar evidencias sobre su incidencia positiva en el desarrollo de la ciudadanía. 3. Y proyectos de intervención social, educativa y/o cultural que puedan destacarse también por su aportación de evidencias de impacto positivo en la población a la que se dirigen. Finalmente, se aportará la discusión sobre el tipo de competencias profesionales en las que se debería incidir desde la formación para facilitar que los equipos fomenten actuaciones de éxito en este campo de la intervención social

Fijación biológica de N2 por Pachecoa venezuelensis en dos suelos de sabana del Oriente Venezolano | Biological nitrogen fixation by Pachecoa venezuelensis in two East Venezuelan savanna soils

Con la finalidad de caracterizar el proceso de nodulación, la infectividad y efectividad de las cepas de rizobia y la eficiencia de la simbiosis Rhizobium spp.-leguminosa con la aplicación de nitrógeno en dos suelos del oriente venezolano, se realizó un experimento en condiciones de invernadero utilizando la leguminosa forrajera arbustiva Pachecoa venezuelensis en un arregloestadístico de parcelas divididas con cuatro repeticiones y sesenta y cuatro combinaciones de tratamientos, donde las parcelas principales fueron los dos tipos de suelos : Jusepín y El Tigre; las subparcelas los dos niveles de nitrógeno edáfico : 0 y 20 kg N.ha-1 y las sub-subparcelas las cepas de rizobia: UDO-R1, RC-14, la combinación de ambas cepas y sin inoculación. A los cuatro meses de la siembra se realizó la cosecha y se determinaron: la altura de las plantas, el peso seco del vástago, de raíz y de nódulos, la concentración de clorofila (a + b), y el porcentaje de nitrógeno del tejido vegetal. Las plantas crecidas en suelode Jusepín alcanzaron la mayor altura promedio (77,67 cm) y los mayores pesos/planta de vástagos (6,50 g ), de raíz (9,81 g) y de nódulos (0,05 g). Se determinó efecto significativo en la interacción Rhizobium spp.-Pachecoa venezuelensis para la concentración de clorofila (a + b). Las plantas crecidas en suelo de El Tigre sin inóculo ni nitrógeno tuvieron un mayor contenido de clorofila (5,69 mg/l/planta). El mayor porcentaje de nitrógeno (2,12 %) se encontró en el tratamiento sin inocular y sin nitrógeno en ambos suelos. Existen rizobia nativos en los suelos Jusepín y El Tigre capaces de nodular efectivamente a Pachecoa. El nitrógeno edáfico ejerció un efecto restrictivo en el contenido de clorofila y en el nitrógeno foliar cuando se inocula Rhizobium spp. a Pachecoa venezuelensis.Palabras claves : Pachecoa venezuelensis, FBN, Rhizobium spp.,rendimientoABSTRACTWith the purpose of characterizing the nodulation process, the infectiveness and effectiveness of rizobia strains and the efficiency of the symbiosis Rhizobium spp-leguminous with nitrogen application in two soils of the Venezuelan Orinoquia, it was carried out an experiment under greenhouse conditions using Pachecoa venezuelensis a forage shrub leguminous. The statistical arrangement was split plot with four repetitions and sixty four combinations of treatments. The main plots were the two types of soils: Jusepín and El Tigre; the subplots the two levels of edaphic nitrogen: 0 and 20 kgN.ha-1 and the subsubplotsthe rizobia strains : UDO-R1, RC-14, the combination of both strains and without inoculation. Plants were harvested four months after planting. It was measured plants height; shoot, root and nodules dry weight; chlorophyll (a + b)concentration and foliage nitrogen. The plants grown in Jusepín soil reached the biggest height average (77.67 cm) and the biggest shoot (6.50 g/plant), root (9.81 g/plant ) and nodules (0.05 g/plant ) dry weights. Significant effect was found in Rhizobium spp - Pachecoa venezuelensis interaction in chlorophyll (a + b) concentration . The plants grown in El Tigre soil with neither inoculums nor nitrogen contained more chlorophyll (5.69 mg/l/plant) than other treatments. The biggest nitrogen percentage (2.12%) it was in the treatment non inoculated and without nitrogen in both soils. Native rizobia exist in both Jusepín and El Tigre soils able to infect Pachecoa. The edaphic nitrogen exerted a restrictive effect in both chlorophyll content and foliage nitrogen when Rhizobium spp inoculated Pachecoa venezuelensis.Key words: Pachecoa venezuelensis, FBN, Rhizobium spp., yiel

Intra-arterial chemotherapy for retinoblastoma: A practical review

The use of chemotherapy for retinoblastoma constitutes a promising treatment strategy. Retinoblastoma is the most common eye cancer in the childhood.. Treatment depends on the laterality, intraocular location and tumor extension. Radiation therapy became an important element in the management of this type of injury risk of extraocular secondary tumor development. Eye salvage is mandatory when vision preserved. The current neuroendovascular techniques constitute a therapeutic tool for these tumors. We present a practical review of current concepts in the management of these tumors