The mechanism of bacteriorhodopsin functioning. I. The light-induced proton throw-over by retinal

The path of proton motion in protein bacteriorhodopsin is constructed: Tyr 43 → Tyr 26 → Asp 212 → Tyr 83 → Tyr 57 → Tyr 79 → Glu 204 → Tyr 64 → Glu 74. From the position of quantum theory the light-induced isomerization of retinal, the process carrying out the proton and throw-over from the inlet H-bond chain (Tyr 43 → Tyr 26 → Lys 216) to the outlet one (Lys 216 → Asp 212 → … → Glu 74) are investigated. The kinetics of the transition of the excitation from the π-electron subsystem to the vibrational one is studied; the function of the nonequilibrial excitation distribution of the collective intramolecular retinal vibrations is found. The mechanism of deprotonation of Schiff base (transmission of proton to the outlet channel) is considered. The correspondence between the theoretically estimated states and spectroscopically identified forms of bacteriorhodosin (initial form bR, intermediates J, K) is proposed.     

Formation of Two-Dimensional Incommensurate Structures in the System of Williams Domains

Abstract

The formation of incommensurate structures and their breakdown in the system of domains is shown with the help of a generalized thermodynamic potential describing Williams domains in nematic liquid crystals above the electrohydro-dynamic instability threshold.     

Comparative structural characterization of the water dispersions of detonation nanodiamonds by small-angle neutron scattering

The structure of nanodiamond water dispersions prepared under different conditions was investigated by small-angle neutron scattering at the scale of 1 to 100 nm. The study of diluted dispersions was regarded as of paramount importance. Similarly to previous studies, strong clustering of particles was revealed in the solutions. The typical size of clusters (40 nm and above) depends on the modification of the dispersions. A common property can be distinguished for different systems: the fractal dimension of the clusters is in the range of 2.3?C2.4, which indicates that there is a common clustering mechanism in such systems. Using contrast variation, the existence of a nondiamond component in the colloidal particles of the dispersions was confirmed; it correlates with the presence of a graphene shell on crystallite surfaces.     

Eine Untersuchung der Konformations-Gleichgewichte von Pyridinal dehyden in Dekahydronaphthalin-L?sung

Ohne Zusammenfassung     

Polarization dependence of the spontaneous radiation of hot electrons

This paper reports on the results of investigations into the polarization dependence of the spontaneous radiation of hot electrons due to their intervalley redistribution in multivalley semiconductors. It is demonstrated that the radiation is predominantly polarized normally to the electric field and the direction of polarization and its intensity can vary according to the degree of electron redistribution, the electron concentration, and the heating electric field.     

Synthesis of multifrequency optical holograms of rotating objects

A two-channel system for synthesizing two-dimensional complex multifrequency optical holograms of rotating objects was developed. In the object irradiation (longitudinal) direction, a hologram is synthesized due to multifrequency laser radiation, and in the transverse direction, the synthesis is provided by object rotation. The object image is reconstructed in the plane coinciding with the plane of its rotation. The resolution of the synthesized hologram in the longitudinal direction is determined by the frequency bandwidth of the laser radiation, and in the transverse direction, the resolution is determined by the initial laser-radiation frequency and the angle of object rotation during the time of hologram synthesis. Using a digital simulation, the degree of isoplanarity of the multifrequency system for synthesizing holograms of rotating objects and its noise immunity under conditions of phase noises were analyzed.     

Proton spin relaxation in a smectic liquid crystal

A proton spin relaxation study in the liquid crystal ethyl-[(methoxybenzylidene)-amino] cinnamate is presented. A “phase change” is observed at ≈ 103°C within the smectic A phase. Some liquid-like mobility exists below this temperature.     

Rotating frame spin-lattice relaxation in the nematic phase of MBBA-d13

Measurements of the deutron and proton spin-lattice relaxation times in the rotating frame in the nematic phase of a partially deuterated MBBA-d₁₃ sample are reported. The rotating frame relaxation rate cannot be explained by the theoretical model of Freed.     

Microstructure and Crystallographic Texture of Silicon Iron Modified by Torsion Under Quasihydrostatic Pressure

Russian Physics Journal - The electron backscatter diffraction, X-ray diffraction analysis, electromotive force instantaneous measurement, microhardness and coercive force measurement techniques...     

Basic patterns of the generation of high-angle grain boundaries and the physical and mechanical properties of FeNi alloys upon severe plastic deformation

The evolution of the structural parameters of deformation fragments and dynamically recrystallized grains in FeNi alloy are analyzed by means of transmission electron microscopy and back-scattered electron diffraction in a Bridgman camera upon severe plastic deformation with an increase in the number of full turns at a room temperature. It is found that the formation of a great many high-angle grain boundaries in the structure is associated with low-temperature dynamic recrystallization.