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- Quantum mechanism of light energy propagation through an avian retinaPublication . Zueva, Lidia; Golubeva, Tatiana; Korneeva, Elena; Resto, Oscar; Inyushin, Mikhail; Khmelinskii, Igor; Makarov, VladimirTaking into account the ultrastructure of the Pied Flycatcher foveal retina reported earlier and the earlier reported properties of Muller cell (MC) intermediate filaments (IFs) isolated from vertebrate retina, we proposed a quantum mechanism (QM) of light energy transfer from the inner limiting membrane level to visual pigments in the photoreceptor cells. This mechanism involves electronic excitation energy transfer in a donor-acceptor system, with the IFs excited by photons acting as energy donors, and visual pigments in the photoreceptor cells acting as energy acceptors. It was shown earlier that IFs with diameter 10 nm and length 117 mu m isolated from vertebrate eye retina demonstrate properties of light energy guide, where exciton propagates along such IFs from MC endfeet area to photoreceptor cell area. The energy is mostly transferred via the contact exchange quantum mechanism. Our estimates demonstrate that energy transfer efficiencies in such systems may exceed 80-90%. Thus, the presently developed quantum mechanism of light energy transfer in the inverted retina complements the generally accepted classic optical mechanism and the mechanism whereby Muller cells transmit light like optical fibers. The proposed QM of light energy transfer in the inverted retina explains the high image contrast achieved in photopic conditions by an avian eye, being probably also active in other vertebrates.
- Spectral selectivity model for light transmission by the intermediate filaments in Muller cellsPublication . Khmelinskii, Igor; Golubeva, Tatiana; Korneeva, Elena; Inyushin, Mikhail; Zueva, Lidia; Makarov, VladimirPresently we continue our studies of the quantum mechanism of light energy transmission in the form of excitons by axisymmetric nanostructures with electrically conductive walls. Using our theoretical model, we analyzed the light energy transmission by biopolymers forming optical channels within retinal Muller cells. There are specialized intermediate filaments (IF) 10-18 nm in diameter, built of electrically conductive polypeptides. Presently, we analyzed the spectral selectivity of these nanostructures. We found that their transmission spectrum depends on their diameter and wall thickness. We also considered the classical approach, comparing the results with those predicted by the quantum mechanism. We performed experimental measurements on model quantum waveguides, made of rectangular nanometer-thick chromium (Cr) tracks. The optical spectrum of such waveguides varied with their thickness. We compared the experimental absorption/transmission spectra with those predicted by our model, with good agreement between the two. We report that the observed spectra may be explained by the same mechanisms as operating in metal nanolayers. Both the models and the experiment show that Cr nanotracks have high light transmission efficiency in a narrow spectral range, with the spectral maximum dependent on the layer thickness. Therefore, a set of intermediate filaments with different geometries may provide light transmission over the entire visible spectrum with a very high (similar to 90%) efficiency. Thus, we believe that high contrast and visual resolution in daylight are provided by the quantum mechanism of energy transfer in the form of excitons, whereas the ultimate retinal sensitivity of the night vision is provided by the classical mechanism of photons transmitted by the Muller cell light-guides.