Polarization Properties of Photoluminescence of Anisotropic Polymer Films Containing Aligned Au Nanorods and Semiconductor Nanoparticles of Various Shape

Semiconductors - Anisotropic polymer films containing aligned Au nanorods and semiconductor nanoparticles of various shape were fabricated. The photoluminescence of semiconductor nanoparticles in...     

Development and introduction of information technologies for supporting the management of maintenance and repairs at nuclear power stations

The results obtained from introduction of information technologies for supporting the management of maintenance and repairs at nuclear power stations operated by the Rosenergoatom Concern are analyzed. It is shown that the list of promising lines in which information support can be implemented for maintenance and repairs and for managing the main assets of nuclear power stations taking their technical state into account includes introduction of an information system of the EAM class, the reliability-centered maintenance methodology, and other approaches for optimizing the strategies of repair activities, the technology of 3D simulation of elements, and use of 3D models for optimizing repair costs, including the development of interactive technological manuals and teaching systems, as well as integration with the automated process control system and introduction of the project management methodology.     

A method for selecting three-photon positronium-annihilation events with a multidetector coincidence spectrometer

A method for event selection takes into account all features of orthopositronium-atom annihilation. The spectral and angular distributions of positronium three-photon decay was investigated with the 4π-spectrometer ARGUS. The filtration program for the events corresponding to the three-photon positronium decay was developed, and positronium 3γ-annihilation was simulated by the Monte Carlo method. The measured spectra agree well with the simulation. The technique developed will be used to test the quantum electrodynamics of bound state.     

Distribution and biotransformation of labelled pantothenate in cytoplasmic and mitochondrial fractions of the rat liver with a deficiency of pantothenic acid

Experiments were conducted on white rats given synthetic rations devoid of pantothenic acid during 10 weeks. Intensification of 14C-pantothenate deposition was recorded 30 min and 4 h after its intraperitoneal administration. The mitochondrial fraction of the liver accumulated the isotope in time. High-performance liquid chromatography used for separation of the vitamin labeled metabolites has revealed phosphopantothenate (pantothenate), phosphopantothein, CoA and dephospho-CoA (pantetein) in the liver homogenate, while in the mitochondria extracts only CoA and dephospho-CoA (pantetein) were detected. It has been suggested that dephosphorylation of pantothenate metabolites and rapid transformation of phosphopantetein into CoA may take place during the separation of the fractions.     

Developing the concept of maintenance and repairs in projects of power units for new-generation nuclear power stations

Results from conceptual elaboration of individual requirements for the system of maintenance and repairs that must be implemented in the projects of new-generation nuclear power stations are presented taking as an example the power unit project for a nuclear power station equipped with a standard optimized VVER reactor with enhanced information support (the so-called VVER TOI reactor). Implementation of these concepts will help to achieve competitiveness of such nuclear power stations in the domestic and international markets.     

A Genome-Wide Association Study of 2304 Extreme Longevity Cases Identifies Novel Longevity Variants

We performed a genome-wide association study (GWAS) of human extreme longevity (EL), defined as surviving past the 99th survival percentile, by aggregating data from four centenarian studies. The combined data included 2304 EL cases and 5879 controls. The analysis identified a locus in CDKN2B-AS1 (rs6475609, p = 7.13 × 10⁻⁸) that almost reached genome-wide significance and four additional loci that were suggestively significant. Among these, a novel rare variant (rs145265196) on chromosome 11 had much higher longevity allele frequencies in cases of Ashkenazi Jewish and Southern Italian ancestry compared to cases of other European ancestries. We also correlated EL-associated SNPs with serum proteins to link our findings to potential biological mechanisms that may be related to EL and are under genetic regulation. The findings from the proteomic analyses suggested that longevity-promoting alleles of significant genetic variants either provided EL cases with more youthful molecular profiles compared to controls or provided some form of protection from other illnesses, such as Alzheimer’s disease, and disease progressions.     

Coherent bremsstrahlung and parametric X-ray radiation from nonrelativistic electrons in a crystal

X-ray radiation generated by nonrelativistic electrons interacting with a crystal target exhibits several distinctive features in comparison to the relativistic case. The difference is related to the interference of the parametric X-ray radiation and coherent bremsstrahlung, which takes place for the nonrelativistic electrons. The characteristics of this radiation have been studied in the Bragg and Laue geometries in an electron microscope using a beam of electrons with energies in the 50–100 keV range. The necessary requirements on the target parameters, the measuring instrumentation, and the experimental geometry are established. Variation of the X-ray radiation frequency depending on the angle of electron beam incidence on the target in the region of non-relativistic electron energies has been observed for the first time. The X-ray radiation frequency has been also studied as a function of the primary electron beam energy. Tunable soft X-ray radiation with quantum energy in the range below 1 keV is obtained. The radiation quantum yield per electron within a unit solid angle amounts to ～10^?8.