990 resultados para Polarization (Light)


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A normal-incidence nonpolarizing guided-mode resonance filter is designed. There are two waveguide layers and one grating layer in the filter. By adjusting the distance between the two waveguide layers, the same resonance wavelength for both TE and TM polarization can be achieved. An antireflection design method is also used to decrease the sideband reflection of the filter. The results show that the filter has high reflection, more than 99.9% at 500 nm, and the FW-HMs of TE- and TM-polarized light are 2.16 and 0.15 nm, respectively. (C) 2009 Optical Society of America

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Organic light-emitting diodes (OLEDs) using tris-(8-hydroxy-quinolinato) aluminum (Alq(3)) as an emitter, 8-hydroxy-quinolinato lithium (Liq) as an electron injection layer, were prepared. Experimental results show that the efficiency of device with Liq is three times higher than that without Liq. The device using Liq as an injection layer is less sensitive in efficiency to the Liq thickness than that using LiF. In addition to the Alq3 based devices, Liq is also very effective as an electron injection layer for 4,4'-bis(2,2-diphenylvinyl)-1,1'-biphenyl based blue OLED and poly (2-methoxy,5-(2-ethyl-hexyloxy)-1,4-phenylenevinylene) based orange polymer OLED. (c) 2004 Elsevier B.V. All rights reserved.

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Demersal fishes hauled up from depth experience rapid decompression. In physoclists, this can cause overexpansion of the swim bladder and resultant injuries to multiple organs (barotrauma), including severe exophthalmia (“pop-eye”). Before release, fishes can also be subjected to asphyxia and exposure to direct sunlight. Little is known, however, about possible sensory deficits resulting from the events accompanying capture. To address this issue, electroretinography was used to measure the changes in retinal light sensitivity, flicker fusion frequency, and spectral sensitivity in black rockfish (Sebastes melanops) subjected to rapid decompression (from 4 atmospheres absolute [ATA] to 1 ATA) and Pacific halibut (Hippoglossus stenolepis) exposed to 15 minutes of simulated sunlight. Rapid decompression had no measurable influence on retinal function in black rockfish. In contrast, exposure to bright light significantly reduced retinal light sensitivity of Pacific halibut, predominately by affecting the photopigment which absorbs the green wavelengths of light (≈520–580 nm) most strongly. This detriment is likely to have severe consequences for postrelease foraging success in green-wavelength-dominated coastal waters. The visual system of Pacific halibut has characteristics typical of species adapted to low light environments, and these characteristics may underlie their vulnerability to injury from exposure to bright light.

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We analysed the whole-genome transcriptional profile of 6 cell lines of dark melanocytes (DM) and 6 of light melanocytes (LM) at basal conditions and after ultraviolet-B (UVB) radiation at different time points to investigate the mechanisms by which melanocytes protect human skin from the damaging effects of UVB. Further, we assessed the effect of different keratinocyte-conditioned media (KCM+ and KCM-) on melanocytes. Our results suggest that an interaction between ribosomal proteins and the P53 signaling pathway may occur in response to UVB in both DM and LM. We also observed that DM and LM show differentially expressed genes after irradiation, in particular at the first 6h after UVB. These are mainly associated with inflammatory reactions, cell survival or melanoma. Furthermore, the culture with KCM+ compared with KCM- had a noticeable effect on LM. This effect includes the activation of various signaling pathways such as the mTOR pathway, involved in the regulation of cell metabolism, growth, proliferation and survival. Finally, the comparison of the transcriptional profiles between LM and DM under basal conditions, and the application of natural selection tests in human populations allowed us to support the significant evolutionary role of MIF and ATP6V0B in the pigmentary phenotype.

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In ultracold atoms settings, inelastic light scattering is a preeminent technique to reveal static and dynamic properties at nonzero momentum. In this work, we investigate an array of one-dimensional trapped Bose gases, by measuring both the energy and the momentum imparted to the system via light scattering experiments. The measurements are performed in the weak perturbation regime, where these two quantities-the energy and momentum transferred-are expected to be related to the dynamic structure factor of the system. We discuss this relation, with special attention to the role of in-trap dynamics on the transferred momentum.

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Two relatively inexpensive light traps to capture pre-settling reef fish and invertebrates are described. A trap made from a plastic bucket (with plastic bottles, a small plastic waste bin and two sheets of plywood) that costs US$15 appears to be just as effective as a large aluminium and plexiglass trap that costs US$275.