Excitonic enhancement of nonradiative energy transfer to bulk silicon with the hybridization of cascaded quantum dots

Cataloged from PDF version of article.We report enhanced sensitization of silicon through nonradiative energy transfer (NRET) of the excitons in an energy-gradient structure composed of a cascaded bilayer of green-and red-emitting CdTe quantum dots (QDs) on bulk silicon. Here NRET dynamics were systematically investigated comparatively for the cascaded energy-gradient and mono-dispersed QD structures at room temperature. We show experimentally that NRET from the QD layer into silicon is enhanced by 40% in the case of an energy-gradient cascaded structure as compared to the mono-dispersed structures, which is in agreement with the theoretical analysis based on the excited state population-depopulation dynamics of the QDs. (C) 2013 AIP Publishing LLC

Effect of Build Parameters and Build Geometries on Residual Microstructures and Mechanical Properties of Ti-6Al-4V Components Built by Electron Beam Melting (EBM)

In this study, involving additive manufacturing (AM) using electron beam melting (EBM), we have examined build defects which result from beam tripping, porosities (including unmelted or unsintered zones) due to excursions from optimal build parameters (especially variations in melt scan beam current and scan speed), and gas bubbles trapped in atomized Ti-6Al-4V starting powder as well as recycled powder, and retained in the build. At optimized build conditions we have also examined microstructure-mechanical property (hardness, tensile strength, and elongation) variations for multiple rake building and multiple melt scans using optical metallography and scanning and transmission electron microscopy (SEM and TEM). These build variances cause cooling rate variances which promote α-phase growth and variations in dislocation density, as well as α-to-α' (martensite) phase changes, all of which produce some degree of mechanical property variations. These features (especially α-to-α' phase changes) are notable on comparing solid builds in comparison with a variety of mesh arrays where strut dimension and build-element complexities alter the cooling rates in a significant way. We illustrate these microstructure variations with corresponding variations in microindentation hardness measurements made directly on fine mesh (strut) structures. Finally, we have examined Ti-6Al-4V powder chemistries and solid build chemistries which for single-pass melt scans at optimized build conditions are shown to be relatively constant up to 40 cycles of powder reuse with the exception of Al content which was reduced by 10 to 15% in solid builds at optimized conditions. However, Al loss in solid builds approached 25% for multiple (2 and 3) melt scans, while no changes in Ar gas-bubble density were observed with changes in α-phase (grain) width which increased from 3 µm for a single melt scan to 4.5 and 6 µm for 2 and 3 melt scans, respectively. Corresponding Rockwell C-scale (HRC) hardness varied from 37, 36, and 35, respectively; with ultimate tensile strengths exceeding 1.2 GPa at elongations of 12% or higher for this melt scan sequence.Mechanical Engineerin

Excitonic enhancement of nonradiative energy transfer from a quantum well in the optical near field of energy gradient quantum dots

Cataloged from PDF version of article.We report strong exciton migration with an efficiency of 83.3% from a violet-emitting epitaxial quantum well (QW) to an energy gradient colloidal construct of layered green-and red-emitting nanocrystal quantum dots (NQDs) at room temperature, enabled by the interplay between the exciton population and the depopulation of states in the optical near field. Based on the density matrix formalization of near-field interactions, we theoretically model and demonstrate that the energy gradient significantly boosts the QW-NQDs exciton transfer rate compared to using mono-dispersed NQDs, which is in agreement with the observed experimental results. (C) 2012 American Institute of Physics

Gonadal Development and Sexual Dimorphism of Gobiomorus dormitor from the Estuarine System of Tecolutla, Veracruz, Mexico

The bigmouth sleeper, Gobiomorus dormitor, is a benthic, euryhaline species, and is very abundant in river mouths, coastal lagoons, and sites away from marine influence from south Florida to Dutch Guyana. There are few studies of its life history, ecology, and abundance, particularly within Mexican waters. Nine trips to Tecolutla estuary, Veracruz, Mexico, were taken between October 1995 and May 1998 to estimate the gonadal development and sexual dimorphism of G. dormitor. A total of 94 individuals ranging from 15–260 mm SL and 0.05–181 g were captured. Seventy-two specimens were adults (60 females, 12 males) and 22 were juveniles that did not show external sexual dimorphism. Both juvenile and adult stages of G. dormitor were captured year-round in seagrass beds and adjacent shallow, muddy or sandy areas. This study has shown that G. dormitor are resident and undergo sexual maturation in the Tecolutla estuary. Histological evidence suggests both males and females undergo gonadal recrudescence in the estuary and have an extended reproductive season from May through November. However, it is unclear if the species actually spawns in the estuary, since females in the final stages of oocyte maturation were not captured. Additional research on the reproductive biology and ecology of this under-studied species is necessary to determine its role in tropical estuaries in the southern Gulf of Mexico. Information learned from areas in the center of its distribution may aid in conserving the species at the periphery of its range in Florida, where it is considered threatened

Basic principles for the development of an application to bi-manipulate boxes with a humanoid robot

[EN] Logistics is a sector which is continuously growing, due to globalization, as well as the current situation caused by the Covid. In this article, an application to recognize boxes is described. The characteristics are extracted with the goal of identify the opening side of the box by using computer vision techniques. This goal has been achieved considering the dimensions, as well as, the position in the space of the box. Those characteristics were obtained processing 2D and 3D images. Then, this information has been classified by using a decision tree based on the human knowledge. The probability of each of the six faces to be the opening side is obtained. This article is a base to develop in the future an application in which the humanoid robot TEO is capable to learn the optimal way to find the opening of boxes and bimanipulate them to be opened in an automated system.[ES] La logística es un sector que está en continuo crecimiento, debido tanto a la globalización, como a la actual situación creada por el Covid. En este artículo se describe una aplicación para reconocer cajas, extrayendo sus características con el fin de identificar la cara de apertura por medio de un sistema de visión por computador. Este objetivo se ha conseguido teniendo en cuenta las dimensiones y la posición en el espacio de la misma, logrando estas características a través de técnicas de procesamiento de imagen en 2D y en 3D. Posteriormente, la información correspondiente a las caras de la caja es clasificada con un árbol de decisiones, obteniendo así la probabilidad de que cada una de las seis caras sea la de apertura. Este artículo sirve para establecer las bases para desarrollar en un futuro una aplicación en la que el robot humanoide TEO mediante aprendizaje encuentre la forma más óptima de bimanipular cajas y abrirlas, integrando este conocimiento en un sistema automatizado.Este trabajo ha sido realizado parcialmente gracias al apoyo de RoboCity2030-DIH-CM; Madrid Robotics Digital Innovation Hub, S2018/NMT-4331, fundado por “Programas de Actividades I+D en la Comunidad de Madrid” y cofundado por los fondos estructurales de la UE.Hernandez-Vicen, J.; Martinez, S.; Balaguer, C. (2021). Principios básicos para el desarrollo de una aplicación de bi-manipulación de cajas por un robot humanoide. Revista Iberoamericana de Automática e Informática industrial. 18(2):129-137. https://doi.org/10.4995/riai.2020.13097OJS129137182Galeano, S. 2019. El ecommerce español se quedó a las puertas de la barrera psicológica de los 40.000 millones de euros en 2018. 2019, de marketing4ecommerce Sitio web: https://marketing4ecommerce.net/facturacion-anual-ecommerce-espanol-no-supera-40-000-mme-cnmc-2018/World Bank Group, 2019. Country Score Card: Spain 2018. Recuperado el 12/2019, de World Bank Group Sitio web: https://lpi.worldbank.org/international/scorecard/line/254/C/ESP/2018/C/ESP/2016/C/ESP/2014/C/ESP/2012/C/ESP/2010/C/ESP/2007#chartareaGarcía Juez, I. 2017. La logística y el transporte en España suponen el 8% del PIB y y emplean a 800.000 personas. Ok Diario. Recuperado el 12/2019 de https://okdiario.com/economia/sector-logistica-transporte-espana-supone-8-del-pib-emplea-800-000-personas-1368706Echelmeyer, W., Kirchheim, A., & Wellbrock, E. (2008, September). Robotics-logistics: Challenges for automation of logistic processes. In 2008 IEEE International Conference on Automation and Logistics (pp. 2099-2103). IEEE. https://doi.org/10.1109/ICAL.2008.4636510Martínez, S., Monje, C. A., Jardón, A., Pierro, P., Balaguer, C., & Munoz, D. (2012). Teo: Full-size humanoid robot design powered by a fuel cell system. Cybernetics and Systems, 43(3), 163-180. https://doi.org/10.1080/01969722.2012.659977C. A. Monje, S. Martínez, A. Jardón, P. Pierro, C. Balaguer and D. Muñoz, "Full-size humanoid robot TEO: Design attending mechanical robustness and energy consumption," 2011 11th IEEE-RAS International Conference on Humanoid Robots, Bled, 2011, pp. 325-330. https://doi.org/10.1109/Humanoids.2011.6100835Hernandez-Vicen, J., Martinez, S., Garcia-Haro, J., & Balaguer, C. (2018). Correction of visual perception based on neuro-fuzzy learning for the humanoid robot TEO. Sensors, 18(4), 972. https://doi.org/10.3390/s18040972Vázquez, E. (2015). Técnicas de visión artificial robustas en entornos no controlados. Tesis doctoral, Universidad de Vigo, Vigo, España. Recuperado el 13 de Enero de 2020, de https://dialnet.unirioja.es/servlet/dctes?codigo=124604Bradski, G., & Kaehler, A. (2008). Learning OpenCV: Computer vision with the OpenCV library. " O'Reilly Media, Inc.".Bradski, G., & Kaehler, A. (2000). OpenCV. Dr. Dobb's journal of software tools, 3.Brahmbhatt, S. (2013). Practical OpenCV. Apress. https://doi.org/10.1007/978-1-4302-6080-6Elfring, J. (2013). Image Processing Using OpenCV. Online (Feb 2018).OpenCV: Hough Line Transform. (2020). Recuperado 20 Enero 2020, de https://docs.opencv.org/3.4/d9/db0/tutorial_hough_lines.htmlde la Escalera, A., Armingol, J. M., Pech, J. L., & Gómez, J. J. (2010). Detección Automática de un Patrón para la Calibración de Cámaras. Revista Iberoamericana de Automática e Informática Industrial RIAI, 7(4), 83-94. https://doi.org/10.1016/S1697-7912(10)70063-7Wang, Y. M., Li, Y., & Zheng, J. B. (2010, June). A camera calibration technique based on OpenCV. In The 3rd International Conference on Information Sciences and Interaction Sciences (pp. 403-406). IEEE. https://doi.org/10.1109/ICICIS.2010.5534797Tesseract-ocr/tesseract. (2020). Recuperado el 20 Enero 2020, de https://github.com/tesseract-ocr/tesseract.Shah, P., Karamchandani, S., Nadkar, T., Gulechha, N., Koli, K., & Lad, K. (2009, November). OCR-based chassis-number recognition using artificial neural networks. In 2009 IEEE International Conference on Vehicular Electronics and Safety (ICVES) (pp. 31-34). IEEE. https://doi.org/10.1109/ICVES.2009.5400240Millán, D. B., Boticario, J. G., & Viñuela, P. I. (2006). Aprendizaje automático. Sanz y Torres.Sempere, J. (2014). Aprendizaje de árboles de decisión. Universidad Politécnica de Valencia, Valencia.Breiman, L. (2017). Classification and regression trees. Routledge. https://doi.org/10.1201/9781315139470Rebollo, F. F., & Barrojo, D. (2009). Aprendizaje por Refuerzo. Aprendizaje Automático, Departamento de Informática, Escuela Politécnica Superior

Localization of Fulicin-like Immunoreactivity in the Central Nervous System and Periphery of Biomphalaria glabrata, an Intermediate Host for Schistosomiasis

An estimate of about ten percent of the population worldwide live at risk of contracting the parasitic disease schistosomiasis, or “snail fever”. The digenetic trematode worm species Schistosoma mansoni that is responsible for causing the most common form of intestinal schistosomiasis requires the freshwater snail Biomphalaria glabrata to serve as its primary intermediate host, where it multiplies and develops into its cercarial form that is infectious to humans. Parasitic castration and parasitic gigantism are among some of the profound behavioral changes that the infection of B. glabrata by S. mansoni is known to cause. For this reason, a neural transcriptomics approach was undertaken to determine precursor prohormones that could encode neuropeptides implicated in Biomphalaria reproductive and feeding behaviors. A transcript (1616 nucleotides) was found to encode a putative precursor polypeptide (316 aminoacids) that could give way to the neuropeptide fulicin (Phe–D-Asn-Glu-Phe-Val-NH2; Ohta et al. 1991; Yasuma Kamatani et al. 1995) and five additional related peptides. For this investigation, affinity purified polyclonal antibodies (rabbit) were developed against the anticipated fulicin neuropeptide. Fulicin-like immunoreactivity was observed throughout the central nervous system (CNS) with distinct neurons and clusters on the ventral and dorsal surfaces, as well as in peripheral tissues. Fulicin-like cells of both large and small diameter were present on the dorsal and ventral surfaces of the buccal ganglion. In addition dispersed clusters of small diameter cells were observed in the cerebral and pedal ganglia. However, in the right pleural ganglion no fulicin-like neurons were present, although it was rich in immunoreactive fibers. Within the left parietal and visceral ganglia, clusters of large prominent cells appeared to give rise to axons projecting to the anal and intestinal nerves. Additionally, peripheral tissue of B. glabrata, specifically regions of the mantle, lip and tentacle were rich in fulicin-like immunoreactive fibers and cell bodies. These results suggest that fulicin and other peptides derived from the fulicin precursor could regulate behaviors related to food intake, reproduction, and growth that are altered during the course of infection in this host-parasite system

Distribution of basement membrane antigens in glomeruli of mice with autoimmune glomerulonephritis.

peer reviewedGlomerulonephritis was induced in mice by the repeated injection of human glomeruli or purified glomerular basement membrane. The glomerular basement membranes of nephritic animals were observed to develop subepithelial extensions, "spikes." Although normally Type IV collagen is found throughout the full thickness of basement membranes, the "spikes" reacted with antibodies to laminin but not with antibodies to Type IV collagen. It is proposed that in murine autoimmune glomerulonephritis, the visceral epithelial cells produce an excess of laminin

Plasmon-Enhanced Energy Transfer in Photosensitive Nanocrystal Device

Förster resonance energy transfer (FRET) interacted with localized surface plasmon (LSP) gives us the ability to overcome inadequate transfer of energy between donor and acceptor nanocrystals (NCs). In this paper, we show LSP-enhanced FRET in colloidal photosensors of NCs in operation, resulting in substantially enhanced photosensitivity. The proposed photosensitive device is a layered self-assembled colloidal platform consisting of separated monolayers of the donor and the acceptor colloidal NCs with an intermediate metal nanoparticle (MNP) layer made of gold interspaced by polyelectrolyte layers. Using LBL assembly, we fabricated and comparatively studied seven types of such NC-monolayer devices (containing only donor, only acceptor, Au MNP-donor, Au MNP-acceptor, donor-acceptor bilayer, donor-Au MNP-acceptor trilayer, and acceptor-Au MNP-donor reverse trilayer). In these structures, we revealed the effect of LSP-enhanced FRET and exciton interactions from the donor NCs layer to the acceptor NCs layer. Compared to a single acceptor NC device, we observed a significant extension in operating wavelength range and a substantial photosensitivity enhancement (2.91-fold) around the LSP resonance peak of Au MNPs in the LSP-enhanced FRET trilayer structure. Moreover, we present a theoretical model for the intercoupled donor-Au MNP-acceptor structure subject to the plasmon-mediated nonradiative energy transfer. The obtained numerical results are in excellent agreement with the systematic experimental studies done in our work. The potential to modify the energy transfer through mastering the exciton-plasmon interactions and its implication in devices make them attractive for applications in nanophotonic devices and sensors. © 2017 American Chemical Society