Results 101 to 110 of about 1,619 (156)
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Spectral Tuning of a Circadian Photopigment in a Subterranean ‘Blind’ Mammal (Spalax ehrenbergi)
FEBS Letters, 1999 The atrophied subcutaneous eyes of Spalax ehrenbergi (the blind mole rat) express a long wavelength sensitive (LWS) cone opsin. Our data provide strong evidence that this photopigment is spectrally tuned to enhance photon capture in the red light ...
Russell G. Foster +2 more
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Photopigments and pseudo-pigments
Vision Research, 1977Abstract The spectral properties of photopigments are often inferred from physiological measures of spectral sensitivity. From these measures pigments have recently been inferred with properties not corresponding to those of any pigment measured by spectrophotometry.
L, Sirovich, I, Abramov
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Vitamin A deprivation and Drosophila photopigments
Nature, 1977VITAMIN A deprivation causes a profound reduction in visual sensitivity and photopigment concentration in the eyes of both vertebrates and invertebrates1,2. In vertebrates vitamin A deprivation results in degeneration of photoreceptor cells3 and decreases the number of intramembrane particles visualised in the disks of rod outer segments by freeze ...
W A, Harris +4 more
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Studies on the photopigment system in Phycomyces
Biochemical and Biophysical Research Communications, 1970Abstract Light-induced changes in optical density in the region of the action spectra of Phycomyces have been found in vivo and in vitro . The optical density changes are reversed after incubation in the dark for 5 to 12 min. Fluorescence excitation peaks at 345 and 460 nm are demonstrated to reflect the optical density changes ...
D S, Berns, J R, Vaughn
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Densitometric Measurement of Human Cone Photopigment Kinetics
Vision Research, 1983 We measured the radiance response function for steady state bleaching lights and the regeneration of the cone visual photopigments using the continuous recording densitometer described by v. Norren and v.d. Kraats. Measurements made on 5 deuteranopes.
Joel Pokorny +2 more
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Photopigments in Central Serous Chorioretinopathy
American Journal of Ophthalmology, 2011To investigate functional abnormalities in eyes with central serous chorioretinopathy (CSC).Observational case series.Sixteen eyes with CSC were enrolled. Autofluorescence densitometry was performed to measure the optical density of the photopigments. Serial fundus autofluorescence (FAF) images were obtained by Heidelberg Retina Angiogram 2.
Akira, Ojima +4 more
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Aging and human cone photopigments
Annual Meeting Optical Society of America, 1986Previous studies1,2 have disagreed about the effects of aging on human cone optical densities. We have examined the question of whether there are age-related changes in the density and half-bleach illuminance of normal observers. We used a color-matching method to measure the optical density of the photopigments within cones.
A E, Elsner +3 more
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Photopigments and circadian systems of vertebrates
Biophysical Chemistry, 1995In the retinal degeneration (rd) mouse the absence of rod cells and the progressive loss of cones does not result in a decrease in circadian phase shifting responses to light. By contrast, rd/rd mice are unable to perform simple visual tasks. In addition, rodless transgenic mice, and mice homozygous for the retinal degeneration slow (rds) mutation ...
S M, Argamaso +5 more
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Optometry and Vision Science, 1992
ABSTRACT The relative rates of absorption of quanta per unit of energy for the various wavelengths can be assessed for the human red, green, and blue photoreceptors by assuming that the responses generated by a photoreceptor are proportional to the rate of absorption of quanta.
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ABSTRACT The relative rates of absorption of quanta per unit of energy for the various wavelengths can be assessed for the human red, green, and blue photoreceptors by assuming that the responses generated by a photoreceptor are proportional to the rate of absorption of quanta.
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