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Light AND (quality OR spectrum)

Rachel C Steinhardt, Timothy Steeves, Brooke Marjorie Wallace, Brittany Moser, Dmitry A Fishman, Aaron P Esser-Kahn
Photothermal processes are utilized across a variety of fields, from separations to medicine, and are an area of active research. Herein, the action of a solar simulator upon carbon black nanoparticles is shown to result in photothermally-initiated chain-growth polymerization of methyl acrylate, butyl acrylate, and methyl methacrylate initiated by benzoyl peroxide. Using methyl acrylate as the model system, products from this reaction are shown to be apparently indistinguishable on the molecular level, but result in unique microstructures relative to the thermal controls...
October 17, 2017: ACS Applied Materials & Interfaces
Emma J Wams, Tom Woelders, Irene Marring, Laura van Rosmalen, Domien G M Beersma, Marijke C M Gordijn, Roelof A Hut
Study objectives: To determine the effect of light exposure on subsequent sleep characteristics under ambulatory field conditions. Methods: Twenty healthy participants were fitted with ambulatory PSG and wrist-actigraphs to assess light exposure, rest-activity, sleep quality, timing and architecture. Laboratory salivary dim-light melatonin onset (DLMO) was analyzed to determine endogenous circadian phase. Results: Later circadian clock phase was associated with lower intensity (R2=0...
October 11, 2017: Sleep
Jenq-Wei Yang, Pierre-Hugues Prouvot, Vicente Reyes-Puerta, Maik C Stüttgen, Albrecht Stroh, Heiko J Luhmann
Parvalbumin (PV) positive interneurons exert strong effects on the neocortical excitatory network, but it remains unclear how they impact the spatiotemporal dynamics of sensory processing in the somatosensory cortex. Here, we characterized the effects of optogenetic inhibition and activation of PV interneurons on spontaneous and sensory-evoked activity in mouse barrel cortex in vivo. Inhibiting PV interneurons led to a broad-spectrum power increase both in spontaneous and sensory-evoked activity. Whisker-evoked responses were significantly increased within 20 ms after stimulus onset during inhibition of PV interneurons, demonstrating high temporal precision of PV-shaped inhibition...
October 13, 2017: Cerebral Cortex
Paolo Zardi, Klaus Wurst, Giulia Licini, Cristiano Zonta
Enantiomeric excess determination is crucial in many aspects of science ranging from synthesis to materials. Within this subject, the use of molecular sensors coupled with chiroptical techniques is a straightforward approach to the stereochemical analysis of chiral molecules, especially in terms of process immediacy and labor. Ste-reodynamic probes typically consist of racemic mixtures of rapidly interconverting enantiomeric conformers able to recognize a chiral analyte and greatly amplify its chiroptical readout...
October 17, 2017: Journal of the American Chemical Society
Nathan Fleer, Kate Pelcher, Jian Zou, Kelly Nieto, Lacey Douglas, Diane Sellers, Sarbajit Banerjee
Buildings consume an inordinate amount of energy, accounting for 30-40% of worldwide energy consumption. A major portion of solar radiation is transmitted directly to building interiors through windows, skylights, and glazed doors where the resulting solar heat gain necessitates increased use of air conditioning. Current technologies aimed at addressing this problem suffer from major drawbacks, including a reduction in the transmission of visible light, thereby resulting in increased use of artificial lighting...
October 17, 2017: ACS Applied Materials & Interfaces
Timur E Gureyev, Alexander Kozlov, David M Paganin, Yakov I Nesterets, Frank De Hoog, Harry M Quiney
A reciprocal relationship between the autocovariance of the light intensity in the source plane and in the far-field detector plane is presented in a form analogous to the classical van Cittert-Zernike theorem, but involving intensity correlation functions. A "classical" version of the reciprocity relationship is considered first, based on the assumption of circular Gaussian statistics of the complex amplitudes in the source plane. The result is consistent with the theory of Hanbury Brown-Twiss interferometry, but it is shown to be also applicable to estimation of the source size or the spatial resolution of the detector from the noise power spectrum of flat-field images...
September 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
S Q Jin, C Huang, G Xia, M Y Hu, Z J Liu
Light-emitting diodes (LEDs) are widely employed in industrial applications and scientific research. However, spectral distortions will occur due to the broadening effects of the spectrometer when an LED spectrum is obtained with a spectrometer. In this paper, a novel approach is put forward to correct bandwidth for an LED spectrum based on a Levenberg-Marquardt algorithm and He-Zheng model. We compare estimation errors of different LED spectra by using the proposed method along with the Richardson-Lucy method and differential operator approach...
September 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Lutful Ahad, Ismo Vartiainen, Tero Setälä, Ari T Friberg, Jari Turunen
We investigate the temporal coherence of random, pulsed, quasi-stationary scalar light fields and introduce a new type of expansion for the mutual coherence function in terms of fully coherent frequency-shifted quasi-monochromatic modes of identical shape. The mode representation is valid provided the pulse length is shorter and the coherence time is much shorter than the width of the time window in which the field is considered. The construction of the expansion is particularly straightforward since information is required only on the average spectrum and the average temporal intensity...
September 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
F G Mitri
Fractional Bessel-Gauss light-sheets [J. Opt.19, 055602 (2017)JOOPDB0150-536X10.1088/2040-8986/aa649a], which correspond to finite optical "slices" in 2D and possess asymmetric slit openings and bending characteristics, are examined from the standpoint of optical radiation force and spin torque theories for a subwavelength spheroid with arbitrary orientation in space. The vector angular spectrum decomposition method in addition to the Lorenz gauge condition and Maxwell's equations are used to determine the Cartesian components of the incident radiated electric field of the Bessel-Gauss light-sheets...
July 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
F G Mitri
This work demonstrates the generation of auto-bending cylindrical/tubular Bessel-Gauss bottle beams in homogeneous two-dimensional (2D) space. The corresponding wave fields flow through a two-dimensional curved trajectory leaving a singularity hollow central region, exhibiting the characteristic of circumventing obstacles. Scalar and vector fields are derived based on the angular spectrum decomposition method, the Helmholtz equation, the Lorenz gauge condition, and Maxwell's equations. The profile and area of the 2D bottle beams, together with the location of the autofocusing spots, are controlled by the intrinsic parameters of the illuminating waves and polarizations of the vector potential forming the incident fields...
July 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Román Castañeda
The interaction between real and virtual point emitters is presented as the propagation principle of light under arbitrary spatial coherence. It is supported on a geometrical interpretation of the two-point correlation and the introduction of the geometrical potential. This principle and the spectrum of classes of point emitters constitute a complete theoretical model that offers a unified phenomenological framework for interference and diffraction not only of light but also of single particles, which is not possible in the conventional formalism based on the wave superposition principle...
June 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Johannes Stock, Norman Girma Worku, Herbert Gross
Propagating electromagnetic light fields between nonparallel planes is of special importance, e.g., within the design of novel computer-generated holograms or the simulation of optical systems. In contrast to the extensively discussed evaluation between parallel planes, the diffraction-based propagation of light onto a tilted plane is more burdensome, since discrete fast Fourier transforms cannot be applied directly. In this work, we propose a quasi-fast algorithm (O(N(3) log N)) that deals with this problem...
October 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Jiyang Li, Yanxiong Niu, Sanbin Chen, Yidong Tan
Microchip lasers are applied as the light sources on various occasions with the end-pumping scheme. However, the vibration, the temperature drift, or the mechanical deformation of the pumping light in laser diodes in the end-pumping scheme will lead to instability in the microchip laser output, which causes errors and malfunctioning in the optic systems. In this paper, the side-pumping scheme is applied for improving the disturbance-resisting ability of the microchip laser. The transverse mode and the frequency purity of the laser output are tested...
October 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Kazutaka Kamiya, Hidenaga Kobashi, Masahide Takahashi, Nobuyuki Shoji, Kimiya Shimizu
SIGNIFICANCE: The progressive accumulation of the calcification may deteriorate corneal transparency, especially in the interpalpebral area, and subsequent visual performance for patients with band keratopathy. However, the detailed quantitative analysis of light scattering or higher-order aberrations on visual performance for these patients so far has not been elucidated. PURPOSE: The aim of this study was to assess the relationship of intraocular forward scattering, corneal backward scattering, and corneal higher-order aberrations with visual acuity in eyes with band keratopathy...
October 13, 2017: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Frédéric Hérault, Marie Damon, Pierre Cherel, Pascale Le Roy
Many QTL affecting meat quality and carcass traits have been reported. However, in most of the cases these QTL have been detected in non-commercial populations. Therefore, a family structured population of 457 F2 pigs issued from an inter-cross between 2 commercial sire lines was used to detect QTL affecting meat quality and carcass traits. All animals were genotyped using the Illumina PorcineSNP60 BeadChip platform. Genome-wide association studies were used in combination with linkage disequilibrium-linkage analysis to identify QTL...
September 28, 2017: Meat Science
Emily H Pilkington, May Lai, Xinwei Ge, William J Stanley, Bo Wang, Miaoyi Wang, Aleksandr Kakinen, Marc-Antoine Sani, Michael R Whittaker, Esteban N Gurzov, Feng Ding, John F Quinn, Thomas P Davis, Pu Chun Ke
Protein aggregation into amyloid fibrils is a ubiquitous phenomenon across the spectrum of neurodegenerative disorders and type 2 diabetes. A common strategy against amyloidogenesis is to minimize the populations of toxic oligomers and protofibrils by inhibiting protein aggregation with small molecules or nanoparticles. However, melanin synthesis in nature is realized by accelerated protein fibrillation to circumvent accumulation of toxic intermediates. Accordingly, we designed and demonstrated the use of star-shaped poly(2-hydroxyethyl acrylate) (PHEA) nanostructures for promoting the aggregation while ameliorating the toxicity of human islet amyloid polypeptide (IAPP), the peptide involved in glycemic control and the pathology of type 2 diabetes...
October 16, 2017: Biomacromolecules
Yutaro Tsuji, Keiya Yamamoto, Kosei Yamauchi, Ken Sakai
In order to realize the artificial photosynthetic devices splitting water to H2 and O2 (2H2O + hν → 2H2 + O2), it is desirable to utilize a wider wavelength range of light that extends to a lower energy region of solar spectrum. Here we report a triruthenium photosensitizer [Ru3(dmbpy)6(μ-HAT)]6+ (dmbpy = 4,4'-dimethyl-2,2'-bipyridine, HAT = 1,4,5,8,9,12-hexaazatriphenylene), which absorbs near-infrared light up to 800 nm based on its 1MLCT transition. Importantly, [Ru3(dmbpy)6(μ-HAT)]6+ is found to be the first example of a photosensitizer which can drive H2 evolution under the illumination of near-infrared light above 700 nm...
October 16, 2017: Angewandte Chemie
Waluga Plaingam, Siriporn Sangsuthum, Wannee Angkhasirisap, Tewin Tencomnao
Potentially useful in the treatment of neurodegenerative disorders, Kaempferia parviflora and Myristica fragrans have been shown to possess a wide spectrum of neuropharmacological activities and neuroprotective effects in vivo and in vitro. In this study, we determined whether and how K. parviflora ethanolic extract and M. fragrans volatile oil could influence the levels of neurotransmitters and the whole proteomic profile in the hippocampus of Sprague Dawley (SD) rats. The effects of K. parviflora and M...
October 2017: Journal of Traditional and Complementary Medicine
Vijay A Mittal, Teresa Vargas, K Juston Osborne, Derek Dean, Tina Gupta, Ivanka Ristanovic, Christine I Hooker, Stewart A Shankman
Schizophrenia is a devastating mental illness that has profound effects on a person's health and quality of life. Exercise represents a promising new treatment option that may supplement current psychosocial and pharmacological interventions for psychosis. A large body of work suggests that exercise can improve cardio-metabolic and health behavior and facilitate neurogenesis in areas of the brain that are notably impacted by psychosis. Recent efforts to incorporate exercise as either stand-alone or adjunctive treatment for individuals with schizophrenia range from yoga and light stretching to moderately intense walking, bike riding, or team sports...
June 2017: Current Treatment Options in Psychiatry
Michela Guglielmotto, Debora Monteleone, Valeria Vasciaveo, Ivan Enrico Repetto, Giusi Manassero, Massimo Tabaton, Elena Tamagno
Alzheimer's disease (AD) is a multifactorial pathology causing common brain spectrum disorders in affected patients. These mixed neurological disorders not only include structural AD brain changes but also cerebrovascular lesions. The main aim of the present issue is to find the factors shared by the two pathologies. The decrease of ubiquitin C-terminal hydrolase L1 (Uch-L1), a major neuronal enzyme involved in the elimination of misfolded proteins, was observed in ischemic injury as well as in AD, but its role in the pathogenesis of AD is far to be clear...
2017: Frontiers in Aging Neuroscience
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