STM and STS studies of topological n-type (Bi, In)2(Te, Se, S)3 thermoelectrics.

In topological n-type thermoelectrics based on Bi2Te3 with atomic substitutions Bi → In, Te → Se, S, the morphology and the surface states of Dirac fermions on the interlayer (0001) surface of van der Waals were studied by scanning tunneling microscopy and spectroscopy (STM/STS) techniques. By the STM method, the dark and light spots on the surface were found, which intensities depend on the composition and thermoelectric properties of solid solutions such as the Seebeck coefficient and thermoelectric power factor. The observed surface morphology features in the solid solutions are explained by distortions of surface electronic states originated from atomic substitutions, the influence of doping impurity, and formation mainly of substitutional impurity defects in thermoelectrics. The dips associated with substitutional impurities and antisite defects were found from the analysis of the height profiles obtained on the (0001) surface. Fast Fourier transform of the morphology STM images of the (0001) surface were used to obtain the interference patterns of the quasiparticles excitation caused by surface electrons scattering by defects. The Dirac point energy and its fluctuations, peak energies of surface defects, the positions of the valence and conduction band edges, and the energy gap were determined from an analysis of tunneling spectra. A correlation between the parameters of surface states of Dirac fermions and thermoelectric properties was found. Thus, a contribution of the fermions surface states increases with rise of the surface concentration in solid solutions with high power factor, and the largest concentration value was observed in the Bi1.98In0.02Te2.85Se0.15 composition. The dependences of Fermi energy on the wave vector for different solid solutions are described by a set of Dirac cone sections located within the limits of the fluctuations of the Dirac point energy that explained by weak changes of the Fermi velocity for studied atomic substitutions in sublattices of bismuth telluride.

[Evaluation of the immunogenic and reactogenic properties of vaccine "Euvax B" in persons aged 16-18 years in different geographical zones of Russia].

The comparative evaluation of the reactogenic and immunogenic properties of vaccine "Euvax B" in adolescents aged 16-18 years was carried out in factory housing estate Lvovsky, the Podolsk district, the Moscow region, and in the Yamalo-Nenets Autonomous District (AD): in towns Salekhard, Noyabrsk, Muravlenko, in housing estate Tarko-Sale. The evaluation demonstrated that the use of this vaccine in a dose of 20 mg/ml produced no postvaccinal complications and the frequency of postvaccinal reactions was insignificant. Postvaccinal anti-HBs were detected, on the average, in protective concentrations in 98.4 +/- 1.8% of the vaccines (99.0 +/- 1.9% in the Moscow region, 97.7 +/- 3.2% in the Yamalo-Nenets AD). In most of the vaccinated adolescents high concentrations of postvacinal anti-HBs were detected: in 51.4 +/- 9.7% of the vaccinees in the Moscow region and in 89.7 +/- 6.4% in the Yamalo-Nenets AD they exceeded 1,000 I.U./lit. The conclusion was made that in the territories located in subarctic latitudes vaccinal prophylaxis against hepatitis B was safe and highly effective and have no limitations connected with the conditions of the Far North.

[Changes in structure and functional properties of cytoskeletal elastic protein titin in dilated cardiomyopathy]. / Izmenenie struktury i funktsional'nykh svoistv tsitoskeletnogo élastichnogo belka taitina pri dilatatsionnoi kardiomiopatii.

To elucidate the role of titin in the onset and development of dilated cardiomyopathy, the structure and functional properties of this protein from pathological myocardium (human left ventricle) were studied. By the use of SDS gel electrophoresis, a decrease in molecular weight of titin in dilated cardiomyopathy compared with norm (pig left ventricle) was revealed. The decrease correlated with the stage of the disease. A decrease in the length of molecules of pathological forms of titin was also found by electron microscopy, which confirms the results of electrophoresis tests. It was shown that, unlike titin from healthy muscle, pathological forms of titin do not activate but inhibit the main functional properties of control myosin: the actin-activated ATPase activity and its Ca2+ sensitivity. The direction of the changes in structure and functional properties of titin allows one to conclude about its contribution to the development of the pathology studied.

[Changes in the isoform composition of the cytoskeletal protein titn--adaptation process in hibernation]. / Izmeneniia izoformnogo sostava tsitoskeletnogo belka taitina--adaptatsionnyi protsess pri gibernatsii.

Changes in the isoform composition of the elastic protein titin from skeletal and cardiac muscles of hibernating ground squirrels were revealed for the first time. It was shown that, upon hibernation, the molecular mass of titin decreases and its functional properties change as compared with the active state of the animal. The physiological significance of the changes in titin isoform composition for the inhibition of muscle contractile activity upon hibernation is discussed in connection with similar changes during some cardiomyopathies.