Hydrogen/functionalized benzoquinone for a high-performance regenerative fuel cell as a potential large-scale energy storage platform

The redox flow battery (RFB) is a suitable option for electricity storage due to its high energy efficiency, scalability and relative safety. However, the limited metallic resources for redox materials and the high cost in systems such as the all-vanadium RFB are major challenges for wider application. Organics may be sourced more abundantly and have lower prices than metal based redox couples. In this work a regenerative fuel cell involving relatively inexpensive organic redox couples is demonstrated. The electrochemical properties of 1,2-dihydrobenzoquinone-3,5-disulfonic acid (BQDS) are characterised by cyclic voltammetry and linear-sweep voltammetry under hydrodynamic conditions. A regenerative fuel cell using 0.65 M BQDS in 1 M H2SO4 as positive electrolyte and gaseous hydrogen (1 bar) as negative redox-material results in an open circuit cell voltage of 0.86 V, a power density of 122 mW/cm2, and an energy density of 10.90 Wh L-1 without considering the volume occupied by the hydrogen. Very promising performance with an energy efficiency >60% at 100 mA cm-2 for 200 cycles is reported. New organic redox species resistant to side reactions could facilitate the use of this new system in practical applications. The use of hydrogen may also contribute to reduced side reactions of the organic redox associated with degradation in the presence of oxygen

ANÁLISIS DE LA COMPOSICIÓN FLORÍSTICA EN LA RESERVA PALMA DE CERA, LA VEGA (CUNDINAMARCA, COLOMBIA)

Se determinó la composición estructural de  un bosque húmedo tropical, ubicado en el   municipio de la Vega Cundinamarca en las coordenadas N 4°56'34.85    O 74°21'49.51, a partir de parcelas de 10m por 10m, de acuerdo con la metodología propuesta por Cortolima. Adicionalmente se recolecto material vegetal en zonas de claros y bosque. Se encontraron 9 especies de plantas vasculares en total, donde todas las especies recolectadas poseen un DAP mayor a 10cm. La composición en general es concordante con lo reportado en las áreas boscosas similares, donde las familias identificadas fueron: Hypericaceae, Solanaceae, Asteraceae, Lauraceae, Melastomataceae, Meliaceae,  Cyatheaceae y Salicaceae.

Planificación del sistema integrado de gestión para el sector secundario (construcción) empresa de obras civiles

Se presenta el desarrollo de la implementación del sistema integrado de gestión de una empresa del sector secundario (construcción) dedicado a obras civiles. En la Parte Administrativa cuenta con un sistema de iluminación tanto natural como artificial en buenas condiciones, manteniendo una temperatura y humedad ambiente normal para las personas que se encuentran dentro de las instalaciones, el nivel sonoro en la oficina es de un nivel bajo, las instalaciones eléctricas se encuentran técnicamente distribuidas y en buenas condiciones de seguridad. La ubicación del personal operativo depende en términos generales de las zonas de trabajo de los clientes donde se presta el servicio; estos sitios cuentan con puestos de trabajos adecuados para el cumplimiento seguro de las actividades de su trabajo.The development of the planning of the integrated management system for a company in the secondary sector (construction) dedicated to civil works is presented. In the Administrative Part it has a lighting system both natural and artificial in good condition, maintaining a normal room temperature and humidity for people that are inside the facilities, the noise level in the office is of a low standard, the electrical installations are are technically distributed and in good working order. security. The location of the operational staff depends in terms general of the work areas of the clients where the service is provided service; these sites have suitable jobs for the safe performance of their work activities

Optoelectronic generation of bio-aqueous femto-droplets based on the bulk photovoltaic effect

"© 2020 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited"The generation and manipulation of small aqueous droplets is an important issue for nano- and biotechnology, particularly, when using microfluidic devices. The production of very small droplets has been frequently carried out by applying intense local electric fields to the fluid, which requires power supplies and metallic electrodes. This procedure complicates the device and reduces its versatility. In this work, we present a novel and flexible, to the best of our knowledge, electrodeless optoelectronic method for the production of tiny droplets of biologically friendly aqueous fluids. Our method takes advantage of the photoinduced electric fields generated by the bulk photovoltaic effect in iron-doped lithium niobate crystals. Two substrate configurations, presenting the polar ferroelectric axis either parallel or perpendicular to the active surface, have been successfully tested. In both crystal geometries, small droplets on the femtoliter scale have been obtained, although with a different spatial distributions correlated with the symmetry of the photovoltaic fields. The overall results demonstrate the effectiveness of the optoelectronic method to produce femtoliter droplets, both with pure water and with aqueous solutions containing biological materialMinisterio de Ciencia, Innovación y Universidades of Spain (MAT2017-83951-R); Marie Sklodowska-Curie Action COFUND (713366-InterTalentum

Correlation of the refractive index change at the surface and inside phosphate glass upon femtosecond laser irradiation

This paper was published in JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/josab/viewmedia.cfm?URI=josab-29-10-2665&seq=0&origin=search. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] A study of the surface modification induced by single femtosecond laser pulses in phosphate glass has revealed surface swelling at fluences just below the ablation threshold. This behavior is different from that observed in other dielectric materials. Optical micrographs obtained with monochromatic light show a pattern of Newton rings within the swollen region whose number scales inversely with the illumination wavelength, acting as a micro Fabry-Perot etalon. The swollen surface layer has lower refractive index than the bulk glass and can reach a maximum thickness of 820 nm. We relate these findings to results obtained during subsurface waveguide writing inside phosphate glass, which also show a refractive index decrease at energies near threshold for waveguide fabrication. We have identified low density free-electron plasma to be the trigger of the refractive index change. © 2012 Optical Society of America.We thank Daniel Jaque from the Fluorescence Imaging Group at the Universidad Autonoma de Madrid for providing access to and helping with the confocal microfluorescence imaging system, as well as for many fruitful discussions. We are also grateful to Susana Marcos and Carlos Dorronsoro from IO-CSIC for providing access and assistance to the OIM. This work has been partially supported by the Spanish TEC 2008-01183 and TEC2011-22422. D. Puerto acknowledges his grant of the Spanish Ministry of Science and Education under TEC 2005-0007 and JCI-2010-07479.Puerto Garcia, D.; Siegel, J.; Ferrer, A.; Hernandez-Rueda, J.; Solis, J. (2012). Correlation of the refractive index change at the surface and inside phosphate glass upon femtosecond laser irradiation. Journal of the Optical Society of America B. 10(29):2665-2668. https://doi.org/10.1364/JOSAB.29.002665S266526681029Bradley, J. D. B., & Pollnau, M. (2010). Erbium-doped integrated waveguide amplifiers and lasers. Laser & Photonics Reviews, 5(3), 368-403. doi:10.1002/lpor.201000015Della Valle, G., Osellame, R., & Laporta, P. (2008). Micromachining of photonic devices by femtosecond laser pulses. Journal of Optics A: Pure and Applied Optics, 11(1), 013001. doi:10.1088/1464-4258/11/1/013001Sansoni, L., Sciarrino, F., Vallone, G., Mataloni, P., Crespi, A., Ramponi, R., & Osellame, R. (2010). Polarization Entangled State Measurement on a Chip. Physical Review Letters, 105(20). doi:10.1103/physrevlett.105.200503Siegel, J., Puerto, D., Gawelda, W., Bachelier, G., Solis, J., Ehrentraut, L., & Bonse, J. (2007). Plasma formation and structural modification below the visible ablation threshold in fused silica upon femtosecond laser irradiation. Applied Physics Letters, 91(8), 082902. doi:10.1063/1.2766848Puerto, D., Siegel, J., Gawelda, W., Galvan-Sosa, M., Ehrentraut, L., Bonse, J., & Solis, J. (2010). Dynamics of plasma formation, relaxation, and topography modification induced by femtosecond laser pulses in crystalline and amorphous dielectrics. Journal of the Optical Society of America B, 27(5), 1065. doi:10.1364/josab.27.001065Gawelda, W., Puerto, D., Siegel, J., Ferrer, A., Ruiz de la Cruz, A., Fernández, H., & Solis, J. (2008). Ultrafast imaging of transient electronic plasmas produced in conditions of femtosecond waveguide writing in dielectrics. Applied Physics Letters, 93(12), 121109. doi:10.1063/1.2988275Patel, F. D., DiCarolis, S., Lum, P., Venkatesh, S., & Miller, J. N. (2004). A Compact High-Performance Optical Waveguide Amplifier. IEEE Photonics Technology Letters, 16(12), 2607-2609. doi:10.1109/lpt.2004.836350Ferrer, A., Ruiz de la Cruz, A., Puerto, D., Gawelda, W., Vallés, J. A., Rebolledo, M. A., … Solis, J. (2010). In situ assessment and minimization of nonlinear propagation effects for femtosecond-laser waveguide writing in dielectrics. Journal of the Optical Society of America B, 27(8), 1688. doi:10.1364/josab.27.001688Fletcher, L. B., Witcher, J. J., Reichman, W. B., Arai, A., Bovatsek, J., & Krol, D. M. (2009). Changes to the network structure of Er–Yb doped phosphate glass induced by femtosecond laser pulses. Journal of Applied Physics, 106(8), 083107. doi:10.1063/1.3246842Little, D. J., Ams, M., Dekker, P., Marshall, G. D., & Withford, M. J. (2010). Mechanism of femtosecond-laser induced refractive index change in phosphate glass under a low repetition-rate regime. Journal of Applied Physics, 108(3), 033110. doi:10.1063/1.3468490Ferrer, A., Jaque, D., Siegel, J., la Cruz, A. R. de, & Solís, J. (2011). Origin of the refractive index modification of femtosecond laser processed doped phosphate glass. Journal of Applied Physics, 109(9), 093107. doi:10.1063/1.3572268Liu, J. M. (1982). Simple technique for measurements of pulsed Gaussian-beam spot sizes. Optics Letters, 7(5), 196. doi:10.1364/ol.7.000196Ben-Yakar, A., Harkin, A., Ashmore, J., Byer, R. L., & Stone, H. A. (2007). Thermal and fluid processes of a thin melt zone during femtosecond laser ablation of glass: the formation of rims by single laser pulses. Journal of Physics D: Applied Physics, 40(5), 1447-1459. doi:10.1088/0022-3727/40/5/021Brückner, R. (1970). Properties and structure of vitreous silica. I. Journal of Non-Crystalline Solids, 5(2), 123-175. doi:10.1016/0022-3093(70)90190-0Bressel, L., de Ligny, D., Sonneville, C., Martinez, V., Mizeikis, V., Buividas, R., & Juodkazis, S. (2011). Femtosecond laser induced density changes in GeO_2 and SiO_2 glasses: fictive temperature effect [Invited]. Optical Materials Express, 1(4), 605. doi:10.1364/ome.1.000605Eaton, S. M., Zhang, H., Herman, P. R., Yoshino, F., Shah, L., Bovatsek, J., & Arai, A. Y. (2005). Heat accumulation effects in femtosecond laser-written waveguides with variable repetition rate. Optics Express, 13(12), 4708. doi:10.1364/opex.13.00470

Tuberculosis por Mycobacterium bovis en trabajadores de fincas en saneamiento para tuberculosis bovina, de Antioquia, Boyacá y Cundinamarca

Objetivo Realizar la vigilancia epidemiológica clásica y molecular de la tuberculosis (TB) humana causada por Mycobacterium bovis en manipuladores de la cadena de producción bovina en fincas con bovinos PPD positivos de los Departamentos de Antioquia, Boyacá y Cundinamarca en un periodo de un año.Métodos Se visitaron las fincas ganaderas, con bovinos o bufalinos PPD positivos de los departamentos de estudio según información del Programa Nacional de Tuberculosis bovina del ICA. Se recolectó la información socio-demográfica y a los factores de riesgo para adquirir TB asociados a la ocupación a través de una encuesta aplicada a todos los trabajadores de las fincas visitadas. Se recolectaron muestras de esputo luego de haber obtenido un consentimiento informado. Los esputos fueron sometidos a pruebas microbiológicas y moleculares para la identificación de los miembros del complejo M. tuberculosis.Resultados Se visitaron 33 fincas ganaderas y se recolectó información para 164 trabajadores de la cadena de producción bovina. Se identificaron como posibles factores de riesgo para el desarrollo de TB la permanencia en la finca PPD positiva por más de un año, desconocimiento de la enfermedad y presencia de posibles reservorios como perros y gatos. No se encontraron casos de TB por M. bovis ni por M. tuberculosis en los trabajadores de las fincas visitadas.Conclusión No se documentaron casos de la enfermedad por este agente zoonótico en los departamentos de Antioquia, Boyacá y Cundinamarca

2021 roadmap on lithium sulfur batteries

Abstract: Batteries that extend performance beyond the intrinsic limits of Li-ion batteries are among the most important developments required to continue the revolution promised by electrochemical devices. Of these next-generation batteries, lithium sulfur (Li–S) chemistry is among the most commercially mature, with cells offering a substantial increase in gravimetric energy density, reduced costs and improved safety prospects. However, there remain outstanding issues to advance the commercial prospects of the technology and benefit from the economies of scale felt by Li-ion cells, including improving both the rate performance and longevity of cells. To address these challenges, the Faraday Institution, the UK’s independent institute for electrochemical energy storage science and technology, launched the Lithium Sulfur Technology Accelerator (LiSTAR) programme in October 2019. This Roadmap, authored by researchers and partners of the LiSTAR programme, is intended to highlight the outstanding issues that must be addressed and provide an insight into the pathways towards solving them adopted by the LiSTAR consortium. In compiling this Roadmap we hope to aid the development of the wider Li–S research community, providing a guide for academia, industry, government and funding agencies in this important and rapidly developing research space

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

La investigación formativa en ciencias empresariales: .Experiencias de investigación formativa POLIPIF

El material propuesto en el libro resume gran parte de la calidad de los trabajos presentados y la evolución en el desarrollo de las capacidades de los estudiantes en un contexto actual, complejo y retador, que refleja la realidad de las organizaciones actuales sobre escenarios estratégicos y manejo de situaciones complejas, para que, cuando lleguen a ser empleados o emprendedores, sepan afrontar cada paso hacia el cambio