Illumination Models
Mostrando 13-20 de 20 artigos, teses e dissertações.
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13. Photoreversible absorbance changes in solutions of allophycocyanin purified from Fremyella diplosiphon: Temperature dependence and quantum efficiency
Preparations of allophycocyanin isolated from the alga Fremyella diplosiphon show light-induced optical absorbance changes that suggest the presence of a photoconvertible component [Formula: see text] similar to the algal pigments described by J. Scheibe [(1972) Science 176, 1037-1039]. At pH < 4 the allophycocyanin has an absorption maximum at 620 nm. Red i
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14. Compared optical performances of multifocal and monofocal intraocular lenses (contrast sensitivity and dynamic visual acuity)
The functional results (contrast sensitivity and dynamic visual acuity) of 19 multifocal (3M design) and 14 all polymethylmethacrylate biconvex monofocal intraocular lenses (IOLs), 6 mm in optical diameter were compared. Best corrected visual acuity was > or = 8/10 (Monoyer chart) Parinaud 2 in all cases. Major differences of functional performance in favour
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15. Image recognition: Visual grouping, recognition, and learning
Vision extracts useful information from images. Reconstructing the three-dimensional structure of our environment and recognizing the objects that populate it are among the most important functions of our visual system. Computer vision researchers study the computational principles of vision and aim at designing algorithms that reproduce these functions. Vis
The National Academy of Sciences.
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16. Inhibition of thrombosis and intimal thickening by in situ photopolymerization of thin hydrogel barriers.
Thin hydrogel barriers formed on the inner surface of injured arteries by interfacial photopolymerization dramatically reduced thrombosis and intimal thickening in rat and rabbit models of vascular injury. This polymerization technique allowed the synthesis of a thin hydrogel barrier that conformed to the vessel wall, directly blocking contact between blood
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17. Angular orientation of the stable tyrosyl radical within photosystem II by high-field 245-GHz electron paramagnetic resonance.
The 4 K 245-GHz/8.7-T electron paramagnetic resonance spectrum of the stable tyrosyl radical in photosystem II, known as TyrD., has been measured. Illumination at 200 K enhances the signal intensity of TyrD. by a factor of > 40 compared to the signal obtained from dark-adapted samples. This signal enhancement and the unusual line shape of the TyrD. resonance
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18. Na+ movement in a single turnover of the Na pump.
Ouabain-sensitive 22Na efflux from right-side-out membrane vesicles prepared from dog kidney has been examined with a time resolution of 30 msec. The vesicles are preloaded with 22Na and caged ATP [P3-1-(2-nitro)phenylethyl adenosine triphosphate], so that transport by the Na pump can be initiated by light. After a brief illumination, which releases less ATP
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19. Transducin-alpha C-terminal mutations prevent activation by rhodopsin: a new assay using recombinant proteins expressed in cultured cells.
We have measured the activation by recombinant rhodopsin of the alpha-subunit (alpha 1) of retinal transducin (Gt, also recombinant) using a new assay. Cultured cells are transiently transfected with DNAs encoding opsin and the three subunits of Gt (alpha t, beta 1 and gamma 1). In the microsomes of these cells, incubated with 11-cis-retinal, light causes th
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20. Single- and double-strand photocleavage of DNA by YO, YOYO and TOTO.
Photocleavage of dsDNA by the fluorescent DNA stains oxazole yellow (YO), its dimer YOYO) and the dimer TOTO of thiazole orange (TO) has been investigated as a function of binding ratio. On visible illumination, both YO and YOYO cause single-strand cleavage, with an efficiency that varies with the dye/DNA binding ratio in a manner which can be rationalized i