1,079 research outputs found

    Nanoscale mechanically induced structural and electrical changes in Ge 2Sb 2Te 5 films

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    We demonstrate that the microstructure and electrical properties of Ge 2Sb 2Te 5 films can be changed by a nanoscale mechanical process. Nanoscratching is used to define modified areas onto an as-deposited crystalline Ge 2Sb 2Te 5 film. Scanning tunneling microscopy measurements show that the modified areas have a very low electrical conductivity. Micro-Raman measurements indicate that the mechanically induced microstructural changes are consistent with a phase transformation from crystalline to amorphous, which can be reversed by laser irradiation.Consejo Superior de Investigaciones Científicas 201060E102Ministerio de Economía y Competitividad CSD2008-00023Junta de Andalucía TEP21

    Preparation of zinc peroxide nanoparticles by laser ablation of solid in liquids

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    We report the preparation of zinc peroxide nanoparticles (ZnO2 NPs ) by the laser ablation of solid in liquids technique. Experiments were performed by using the fundamental wavelength (1064 nm) of a pulsed nanosecond Nd:YAG laser operated at a repetition rate of 15 Hz. A Zn disk (99.99 % purity) were the target and 10 ml of 30% H2O2 solution was used as liquid medium. The per pulse laser fluence was varied. In all the experiments the ablation time was 10 min. The samples were characterized by Raman microspectroscopy, Calorimetry and TEM. Results show that ZnO2 NPs were successfully obtained by this method of preparation

    Meropenem heteroresistance in clinical isolates of OXA-48–producing Klebsiella pneumoniae

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    OXA-48–producing Klebsiella pneumoniae isolates often show growth of colonies within inhibition zones in carbapenem diffusion assays. The nature of these colonies was investigated in a series of clinical isolates of OXA-48–producing K. pneumoniae obtained in the context of a hospital outbreak, and they were found to be persistent colonies that reproduced again the same phenotype when they were collected and tested in diffusion assays again. The frequency of mutations conferring resistance to meropenem (8 µg/mL) was determined for the same isolates. The average mutation frequency was 5.47·10-6 (range: 2.59·10-8–5.87·10-5), and the analysis of several resistant mutants showed that all of them had mutations in the ompK36 porin gene. Heteroresistance was investigated using population analysis profiling. The profiles were compatible with mutation frequency assays, and all the colonies analyzed were resistant mutants. In OXA-48–producing K. pneumoniae, the growth of persisters seems to be specific of diffusion assays

    Depressed-Cladding 3-D Waveguide Arrays Fabricated With Femtosecond Laser Pulses

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    We report on the fabrication of waveguide arrays based on depressed-cladding structures produced by femtosecond laser direct inscription in a Nd:YAG crystal. The arrays consisted of seven divergent hexagonal waveguides with different separations between the waveguides at the exit of the crystal. Optical characterization in the visible (633 nm) and near infrared (800 nm) was performed. The obtained modal profiles show multimodal behavior in the visible and nearly single-mode at 800 nm. The propagation losses were measured to be 1.6-3.0 dB/cm in all the cases. Microluminescence maps were obtained showing the presence of defects only at the damage tracks and a residual stress that slightly affects the waveguide core in the vicinity of the tracks. This affected area is responsible for a modal profile distortion that can be clearly seen at 633 nm, but does not modify the modal profiles in the near infrared. Our results show a very good performance of the fabricated structures and suggest a promising potential use in photonic applications (i.e., photonic lanterns) that can be easily implemented in other transparent materials.This work was supported in part by Junta de Castilla y León (Projects UIC016, SA046U16), MINECO (FIS2013-44174-P, FIS2015-71933-REDT), and in part the Spanish Ministerio de Educación y Ciencia (MAT2013-47395-C4-1-R and MAT2016-75362-C3-1-R). The work of L. Labrador-Páez was supported in part by the Universidad Autónoma de Madrid for the “Formación de Personal Investigador (FPI-UAM)” program

    Shape detection algorithm applicable to solar estimation

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    [EN] This paper presents a bio-inspired hybrid algorithm for shape detection applicable to solar estimation in solar power plants. The objective is to locate and characterise the shape of a cloud over a solar power plant based on low level irradiance measurement with a small fleet of Unmanned Aerial Vehicles (UAVs) equipped with direct normal irradiance sensors. Toe hybrid algorithm takes inspiration and adapts ideas of the ant colony optimisation algorithm (ACO) and also uses a standard cover area algorithm, separating the field into two grids, one for each layer of the algorithm, to find the area affected by the cloud. Once the low irradiance zone is located by one of the UAVs, the others go to help it. This team delimits the cloud border using concepts of an image processing technique. Finally, the algorithm is tested by simulations.[ES] En este artículo se presenta un algoritmo híbrido bio-inspirado para la detección de formas aplicado a la estimación solar en plantas solares. Se tiene como objetivo localizar y caracterizar la forma de una nube sobre una planta solar basándose en medidas de niveles bajos de la irradiancia con una pequeña flota de vehículos aéreos no tripulados (UAVs en inglés) equipados con sensores capaces de medir la irradiancia directa normal. El algoritmo híbrido propuesto se inspira y adapta las ideas del algoritmo de optimización de colonia de hormigas (ant colony optimization, ACO) y también usa un algoritmo estándar de cobertura de área, separándose el campo de la planta solar en dos mallados, uno para cada capa del algoritmo, para encontrar el área afectada por la nube. Cuando un UAV localiza la zona de baja irradiancia, los otros van a ayudarle. Dicho equipo delimita el borde de la nube usando conceptos de técnicas de procesamiento de imágenes. Finalmente, se prueba el algoritmo propuesto mediante simulaciones.Este proyecto ha recibido fondos del European Research Council (ERC) en el marco del programa 'European Union's Horizon 2020 and innovation programme' (grant agreement No 789051).Aguilar-López, JM.; García, RA.; Camacho, EF. (2021). Algoritmo para la detección de formas aplicable a la estimación solar. Revista Iberoamericana de Automática e Informática industrial. 18(3):277-287. https://doi.org/10.4995/riai.2021.14765OJS277287183Aasen, H., Burkart, A., Bolten, A., Bareth, G., 2015. Generating 3d hyperspectral information with lightweight uav snapshot cameras for vegetation monitoring: From camera calibration to quality assurance. ISPRS Journal of Photogrammetry and Remote Sensing 108, 245-259. https://doi.org/10.1016/j.isprsjprs.2015.08.002Acar, E. U., Choset, H., 2000. Critica! point sensing in unknown environments. In: Proceedings 2000 ICRA. Millennium Conference. 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Biomimetics?using nature to inspire human innovation. Bioinspiration & biomimetics 1 (1), Pl. https://doi.org/10.1088/1748-3182/1/1/P01Camacho, E. F., Gallego, A., 2013. Optimal operation in solar trough plants: A case study. Solar Energy 95, 106-117. https://doi.org/10.1016/j.solener.2013.05.029Camacho, E. F., Soria, M. B., Rubio, F. R., Martínez, D., 2012. Control of Solar Energy Systems. Springer Science & Business Media. https://doi.org/10.1007/978-0-85729-916-1Cesetti, A., Frontoni, E., Mancini, A., Zingaretti, P., Longhi, S., 2010. A visionbased guidance system for uav navigation and safe landing using natural landmarks. Joumal of intelligent and robotic systems 57 (1-4), 233. https://doi.org/10.1007/s10846-009-9373-3Choi, Y., Choi, Y., Briceno, S., Mavris, D. N., 2020. Energy-constrained multiuav coverage path planning for an aerial imagery mission using column generation. 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Phantom 3 pro user manual. https: //dl.djicdn.com/downloads/phantom_3/en/Phantom_3_Professional_User_Manual __ V1. 6 .pdf, accessed: 2021-01-18.Dorigo, M., 1991. Ant colony optimization?new optimization techniques in engineering. by Onwubolu, GC, and BV Babu, Springer-Verlag Berlín Heidelberg, 101-117.Galceran, E., Carreras, M., 2013. A survey on coverage path planning for robotics. Robotics and Autonomous systems 61 (12), 1258-1276. https://doi.org/10.1016/j.robot.2013.09.004García, R., Orihuela, L., Millán, P., Rubio, F., Ortega, M., 2020. Guaranteed estimation and distributed control of vehicle formations. International Joumal of Control, 1-24. https://doi.org/10.1080/00207179.2020.1714074Jin, J., Tang, L., 2010. Optima! coverage path planning for arable farming on 2d surfaces. Transactions of the ASABE 53 (1), 283-295. https://doi.org/10.13031/2013.29488Johnson, D. S., McGeoch, L. A., 1997. The traveling salesman problem: A case study in local optimization. Local search in combinatoria! optimization 1 (1), 215-310. https://doi.org/10.2307/j.ctv346t9c.13Kuhn, P., Wilbert, S., Prahl, C., Schüler, D., Haase, T., Hirsch, T., Wittmann, M., Ramirez, L., Zarzalejo, L., Meyer, A., et al., 2017. Shadow camera system for the generation of solar irradiance maps. Solar Energy 157, 157-170. https://doi.org/10.1016/j.solener.2017.05.074Law, E. W., Prasad, A. A., Kay, M., Taylor, R. A., 2014. Direct normal irradiance forecasting and its application to concentrated solar thermal output forecasting-a review. Solar Energy 108, 287-307. https://doi.org/10.1016/j.solener.2014.07.008Nouri, B., Kuhn, P., Wilbert, S., Prahl, C., Pitz-Paal, R., Blanc, P., Schmidt, T., Yasser, Z., Santigosa, L. R., Heineman, D., 2018. Nowcasting of dni maps for the solar field based on voxel carving and individual 3d cloud objects from ali sky images. In: AIP Conference Proceedings. Vol. 2033. AIP Publishing LLC, p. 190011.https://doi.org/10.1063/1.5067196Ntawumenyikizaba, A., Viet, H. H., Chung, T., 2012. An online complete coverage algorithm for cleaning robots based on boustrophedon motions and a* search. In: 2012 8th Intemational Conference on Information Science and Digital Content Technology (ICIDT2012). Vol. 2. IEEE, pp. 401-405.Oksanen, T., Visala, A., 2009. Coverage path planning algorithms for agricultural field machines. Journal offield robotics 26 (8), 651-668. https://doi.org/10.1002/rob.20300Rokhmana, C. A., 2015. The potential of uav-based remate sensing for supporting precision agriculture in indonesia. Procedía Environmental Sciences 24 (2015), 245-253. https://doi.org/10.1016/j.proenv.2015.03.032Sánchez, A., Gallego, A., Escaño, J., Camacho, E., 2018. Temperature homogenization of a solar trough field for performance improvement. Solar Energy 165, 1-9. https://doi.org/10.1016/j.solener.2018.03.001Sánchez, A., Gallego, A., Escaño, J., Camacho, E. F., 2019. 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    B1 Was the Ancestor B Chromosome Variant in the Western Mediterranean Area in the Grasshopper Eyprepocnemis plorans.

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    We analyzed the distribution of 2 repetitive DNAs, i.e. ribosomal DNA (rDNA) and a satellite DNA (satDNA), on the B chromosomes found in 17 natural populations of the grasshopper Eyprepocnemis plorans plorans sampled around the western Mediterranean region, including the Iberian Peninsula, Balearic Islands, Sicily, and Tunisia. Based on the amount of these repetitive DNAs, 4 types of B variants were found: B 1 , showing an equal or higher amount of rDNA than satDNA, and 3 other variants, B 2 , B 24 and B 5 , bearing a higher amount of satDNA than rDNA. The variants B 1 and B 2 varied in size among populations: B 1 was about half the size of the X chromosome in Balearic Islands, but two-thirds of the X in Iberian populations at Alicante, Murcia and Albacete provinces. Likewise, B 2 was about one-third the size of the X chromosome in populations from the Granada province but half the size of the X in the populations collected at Málaga province. The widespread geographical distribution of the B 1 variant makes it the best candidate for being the ancestor B chromosome in the whole western Mediterranean region

    Development of a New Method for the Determination of Manganese, Cadmium, Mercury and Lead in Whole Blood and Amniotic Fluid by Inductively Coupled Plasma Mass Spectrometry

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    Environmental exposure to metals among women, revealed their adverse effects on pregnancy. During this stage, blood levels of some metals increase so research on heavy metals transference from the mother’s blood to the developing foetus is of special interest and much attention has been paid to this matter. The amniotic fluid can be considered as a valuable marker of this prenatal exposure to exogenous factors. The aim of this study was to develop a method for the simultaneous determination of Mn, Cd, Hg, and Pb in whole maternal blood and amniotic fluid by ICP-MS. Strategies were given to minimise memory effects related to mercury and two widespread digestion procedures (open-vessel and microwave-assisted) were compared. Several quality controls, such as methodological and reagent blanks, spiked samples and duplicates were used to test the goodness of the developed method. Once optimised, the method was applied for the monitoring of Mn, Cd, Hg and Pb in 15 maternal blood and amniotic fluid samples obtained at delivery after informed consent. This study establishes that heavy metals pass into and accumulate in amniotic fluid and maternal blood. Thus, mean concentrations of Mn were similar in the two biological fluids studied, 21.6 ng/mL in maternal blood and 20.5 ng/mL in amniotic fluid. Mean Cd and mercury levels in blood and amniotic fluid were 1.3 and 6.3 ng/mL and 3.4 and 3.8 ng/mL, respectively. Concentrations of Pb were 16.4 ng/mL in blood and 13.7 ng/mL in amniotic fluid. Further studies are needed to evaluate the long-term health effects derived from this exposure.Plan Propio of the University of SevilleFundación Farmacéutica Avenzoa

    An Updated Review of Neuropathic Pain Treatm ent: State of Art and Future Prospects

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    El dolor neuropático es un tipo de dolor de difícil manejo con una prevalencia próxima al 10% de la población. Actualmente, existen varios fármacos aprobados para su tratamiento agrupados en distintas líneas. Sin embargo, la eficacia farmacológica es limitada en un número significativo de pacientes, por lo que es necesario desarrollar nuevas estrategias terapéuticas. Varias moléculas se encuentran en fases iniciales de ensayos clínicos en humanos, muchas de las cuales están demostrando resultados esperanzadores. Por otra parte, el conocimiento cada vez más preciso de las distintas vías moleculares implicadas en el dolor neuropático está promoviendo el desarrollo de nuevas moléculas con acción sobre potenciales dianas terapéuticas. Algunos de estos agentes se están ensayando en modelos animales y muestran una significativa potencia analgésica. Por último, el papel del tratamiento no farmacológico en el dolor neuropático, mediante alternativas como la radiofrecuencia, la estimulación o los bloqueos nerviosos, está cobrando una relevancia cada vez mayor en la práctica clínica. El objetivo de este trabajo es revisar el statu quo del tratamiento del dolor neuropático en la actualidad, repasando los fármacos aprobados a día de hoy y sus mecanismos de acción principales, y poniendo especial interés en algunas de las moléculas más novedosas que se encuentran en ensayo clínico en humanos y en desarrollo en modelos animales. Además, se recogen algunas de las estrategias no farmacológicas más relevantes en el manejo del dolor neuropático en la actualidad.Neuropathic pain (NP) is a difficult-to-manage kind of pain that affects 10% of the population. Nowadays, there are some agents that can be used for its treatment, and they are grouped according to different lines. However, their pharmacological effectiveness is only proved on a reduced number of patients. For this reason, new therapeutic strategies need to be developed. Certain molecules currently are on the initial stages of human clinical trials, and many of them are showing encouraging results. Furthermore, there is an increasingly accurate knowledge about the different molecular pathways related to NP. This advance is promoting the development of new molecules with potential therapeutic targets. Some of these agents are being tested with animal models, and they are showing a significant analgesic potency. Finally, non-pharmacological treatment in NP is becoming more important in clinical practice through alternatives such as radio frequency, stimulation, and nerve block therapy. The aim of this work is to review the state of art of NP treatment. For that purpose, the agents approved until today and their main action mechanisms should be considered, with a special emphasis on some of the latest molecules used on human clinical trials and those which are in development with animal models. Moreover, some of the main non-pharmacological strategies used to manage pain nowadays are also reviewed
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