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The contributions of light sterile neutrinos to the properties of active-neutrino oscillations and the properties of double-beta decay are estimated under the assumption of the Majorana nature of neutrinos on the basis of a phenomenological model involving three active and three sterile neutrinos. The appearance and survival probabilities for active neutrinos are determined upon taking into account sterile-neutrino contributions in order to explain all known anomalies in neutrino data at short distances by employing the same test values of the model parameters. Modified graphical dependences of the survival and appearance probabilities for electron neutrinos/antineutrinos in beams of muon neutrinos/antineutrinos on the distance and other model parameters at various neutrino energies, as well as on the ratio of the distance to the neutrino energy, are presented. A significant distinction between the probability curves within the neutrino model being considered and the simple sinusoidal curves based on the neutrino model involving only one sterile neutrino is found. The effective electron-neutrino masses for beta decay and for neutrinoless double-beta decay are estimated in the presence of the sterile-neutrino contributions. In addition, the properties of selenium-82 two-neutrino double-beta decay are calculated. These results can be used in interpreting and predicting the results of ground-based experiments aimed at searches for sterile neutrinos and neutrinoless double-beta decay. [ABSTRACT FROM AUTHOR]

The interlayer interactions in multilayer systems with a non-magnetic semimetallic interlayer are great of interest. The magnetic and structural properties of the DyxCo1-x/Bi/Py systems (17 < x < 26 at.%) have been studied. The temperature dependences of magnetization in the range 4.2–300 K were measured for the first time. The influence of the bismuth interlayer thickness on the exchange interaction between the DyCo and Py layers was found as well as the critical value of its thickness. The obtained atypical value of the period of exchange bias oscillations was explained by the formation of bismuth compounds with dysprosium–pnictogenides at bismuth thicknesses below the critical value. The interface was investigated by spectral ellipsometry in the range 2–5 eV. The information on the structure of the surface obtained by atomic force microscopy was used to create a multilayer model for fitting experimental ellipsometric data. Analysis of the optical properties showed that pnictogenide Dy3Bi2 is formed at the interface, which affects the general magnetic state of the samples studied. [ABSTRACT FROM AUTHOR]

While preparing for an experiment on the search for neutrinoless double β decay of 150Nd nuclei, the spectrometric properties of polystyrene were investigated, including the dependence of the photomultiplier pulse amplitude on the energy of detected electrons. It is shown that a good description of experimental data is attained by taking the energy loss in passive materials, changes in the ionization density at low energies, and additional light due to Cherenkov radiation generated in polystyrene into account. [ABSTRACT FROM AUTHOR]

We describe a capacitive dilatometer for measuring the magnetostriction, piezoelectric effect, and linear thermal-expansion coefficient in the temperature range from 1.85 to 350 K in external magnetic fields of up to 90 kOe under a voltage of 1 kV, which operates on the basis of a Quantum Design PPMS commercial facility for studying the properties of solids. [ABSTRACT FROM AUTHOR]

The paper presents geochronological data and results of petrological modeling of the Monchegorsk and Monchetundra layered massifs. The U-Pb ID-TIMS zircon dating of norite from the marginal zone of Mt. Nittis yielded 2506 ± 7 Ma, which coincides with previous data on similar rocks from other areas. Based on the comparison of sections of the Monchegorsk and Kivakka massifs, the pre-erosion thickness of the Monchegorsk massif is estimated as 3700 m. Calculations using rocks of the marginal zone of the Monchegorsk intrusion at a pressure of 6.5–5.5 kbar showed that the melt in equilibrium with Ol contained SiO2 ≤ 55 wt %, TiO2 ≤ 0.50 wt %, and MgO ≤14 wt %. The temperature of the primary magma could be equal to 1390°C. At a lower pressure (below 6.5 kbar), the obtained melt becomes more siliceous. In the Monchegorsk intrusion, the composition of intratelluric olivine according to this model could vary within 88–92 mol % Fo. The content of intratelluric olivine in the melt, depending on pressure, could vary from 11 to 24 vol %. Magmas that formed the Monchegorsk intrusion and the layered series of the Monchetundra intrusion (hole 742) were derived from different sources. [ABSTRACT FROM AUTHOR]

Nuclear γ-resonance experiments with energy and time resolved detection are carried out with ϵ-F2O3 nanoparticles and a 57Co(Rh) laboratory Mössbauer source of γ radiation and a 14.4125 keV synchrotron radiation source on the ID18 beamline (ESRF) in the temperature range of 4–300 K. Both methods show a tremendous increase in the hyperfine field in tetrahedrally coordinated iron positions during the magnetic transition in the range of 80–150 K. As a result, the splitting of the quantum beat peaks in the nuclear scattering spectra is observed in the time interval of 20–170 ns with a periodicity of ∼ 30 ns. In addition, the first quantum beat is slightly shifted to shorter times. A correlation between the quadrupole shift and the orbital angular momentum of iron in ϵ-F2O3 nanoparticles is found. The magnetic transition leads to the rotation of the magnetic moment in the tetrahedral positions of iron around the axis of the electric field gradient by an angle of 44°. [ABSTRACT FROM AUTHOR]

Evolution of the local environment of Fe3+ ions in deposited Fe2O3/SiO2 nanoparticles formed in samples with different iron contents was investigated in order to establish the conditions for obtaining the stable ε-Fe2O3/SiO2 samples without impurities of other iron oxide polymorphs. Microstructure of the samples with an iron content of up to 16% is studied by high-resolution transmission electron microscopy, X-ray diffraction analysis, and Mössbauer spectroscopy, and their magnetic properties are examined. At iron concentrations below 6%, calcinations of iron-containing precursor nanoparticles in a silica gel matrix lead to the formation of the ε-Fe2O3 iron oxide polymorphic modification without foreign phase impurities, while at the iron concentration in the range of 6-12%, the hematite phase forms in the sample in the fraction of no more than 5%. It is concluded on the basis of the data obtained that the spatial stabilization of iron-containing particles is one of the main factors facilitating the formation of the ε-Fe2O3 phase in a silica gel matrix without other iron oxide polymorphs. It is demonstrated that the increase in the iron content leads to the formation of larger particles in the sample and gradual changes of the Fe3+ ion local environment during the phase transition ε-Fe2O3 → α-Fe2O3. [ABSTRACT FROM AUTHOR]

The magnetic structure of the mixed rare-earth system Pr x Y1-x Fe3(BO3)4 (x  =  0.75, 0.67, 0.55, 0.45, 0.25) was studied via magnetic and resonance measurements. These data evidence the successive spin reorientation from the easy-axis antiferromagnetic structure formed in PrFe3(BO3)4 to the easy-plane one of YFe3(BO3)4 associated with the weakening of the magnetic anisotropy of the Pr subsystem due to its diamagnetic dilution by nonmagnetic Y. This reorientation occurs through the formation of an inclined magnetic structure, as was confirmed by our previous neutron research in the range of x  =  0.67 ÷ 0.45. In the compounds with x  =  0.75 and 0.67 whose magnetic structure is close to the easy-axis one, a two-step spin reorientation takes place in the magnetic field H||c. Such a peculiarity is explained by the formation of an interjacent inclined magnetic structure with magnetic moments of Fe ions located closer to the basal plane than in the initial state, with these intermediate states remaining stable in some ranges of the magnetic field. An approach based on a crystal field model for the Pr(3+) ion and the molecular-field approximation is used to describe the magnetic characteristics of the system Pr x Y1-x Fe3(BO3)4. With the parameters of the d-d and f-d exchange interactions, of the magnetic anisotropy of the iron subsystem and of the crystal field parameters of praseodymium thus determined, it is possible to achieve a good agreement between the experimental and calculated temperature and field dependences of the magnetization curves (up to 90 kOe) and magnetic susceptibilities (2-300 K).

The optical activity of DNA liquid-crystalline dispersions is being investigated based on a theory for absorption of electromagnetic waves by large molecular aggregates. The impact on the dispersions-optical properties, exerted by the interaction between the complexes of nucleic acid molecules and nanoparticles, is being considered.

A problem on the electrostatic interaction of two homogeneously charged macromolecular rods of a finite length, submerged into an electrolyte solution was considered. An explicit expression for the energy of interaction and rotational moment as a function of the angle of rotation between the long axes of the molecules was obtained. At small angles of rotation, the expression for energy turns into the corresponding formula for parallel rods, and the rotational moment tends to zero, as it follows from geometrical considerations. The possibility is discussed whether the study is applicable to real biological systems, including liquid-crystalline dispersions of DNA.

Three variants of the model for the formation of "bridges" between the nucleic acid molecules fixed in the structure of particles of liquid-crystalline dispersions were considered. What the three variants have in common is that the bridges represent polymeric chelate cross-links consisting of alternating molecules of daunomycin and copper ions. The differences between the three variants are that in the first variant, the bridges begin and end with daunomycin molecules that form a complex by the mechanism of external binding with nucleic acids; in the second variant, the bridges begin and end with copper ions coupled with the pairs of bases of nucleic acids; and in the third variant, the bridges begin with the daunomycin molecule and end with the copper ion. For each variant, a mathematical model was constructed, which describes the formation of bridges, and equations of binding were derived. The results of calculations were compared with the experimental data. Within the framework of each variant, the values of the energy of interaction between the daunomycin molecule and the copper ion in the bridge, the energy of interaction of the daunomycin molecule with the nucleic acid, and the length of the bridge were varied. For all variants, those values of the parameters were chosen that fit best the experimental data. The theoretical curves obtained using the three variants of the model agree rather well with the family of experimental curves. The best agreement between the theoretical and experimental data was obtained when the polymeric chelate bridge includes more than two daunomycin molecules.

Serum titer achieved while producing antibodies to Y. pseudotuberculosis surface antigens with the use of colloid gold as adjuvant was as high as that achieved with the use of Freund's complete adjuvant (1:10,240). Still the amount of the antigen introduced when colloid gold particles were used as adjuvant was lower by 2 orders. The study revealed that colloid gold used as antigen carrier activated the phagocytic activity of lymphoid cells.

Right-handed helical double-stranded DNA molecules were shown to interact with chitosans to form under certain conditions (chitosan molecular weight, content of amino groups, distance between amino groups, ionic strength and pH of solution) cholesteric liquid-crystalline dispersions characterized by abnormal positive band in CD spectrum in the absorption region of DNA nitrogen bases. Conditions were found for the appearance of intense negative band in CD spectrum upon dispersion formation. In some cases, no intense band appeared in CD spectrum in spite of dispersion formation. These results indicate not only the multiple forms of liquid-crystalline dispersions of DNA-chitosan complexes but also a possibility to control the spatial properties of these complexes. The multiplicity of liquid-crystalline forms of DNA-chitosan complexes was attempted to explain by the effect of character of dipoles distribution over the surface of DNA molecules on the sense of spatial twist of cholesteric liquid crystals resulting from molecules of the complexes.

Abnormal optical properties of liquid-crystalline dispersions (phases) formed as a result of phase exclusion of double-stranded DNA and RNA from water-salt poly(ethylene glycol) solutions and X-ray parameters of these phases are compared. It is shown that the cholesteric packing of nucleic acid molecules is realized at the certain osmotic pressure of a solvent only. A comparison of the optical properties of liquid-crystalline phases (dispersions) to their X-ray parameters allows one to put forward a suggestion on various hydratation (fluctuation) regimes of the nucleic acid behaviour under the condensed phases formation and factors, influencing the mode of packing of these molecules in phases formed. It is shown as well, that immobilization of DNA cholesteric liquid-crystalline particles in the content of polymeric matrix is accompanied by the stabilization of these particles and, hence, their specific abnormal optical activity as well as by formation of particles having a structure, which corresponds to the "optically isotropic ordered liquid" without abnormal optical activity. Data on stabilization of the cholesteric structure of liquid-crystalline DNA dispersions by creation of polymeric chelate bridges between the neighbouring DNA molecules, fixed in the structure of liquid-crystalline dispersions, are shown.

The study of the use of ozone-containing solutions in 40 experimental animals and in 58 patients with diffuse purulent peritonitis revealed their marked detoxicant effect that manifested with early decrease of ESR, leucocytosis, plasma concentration of bilirubin and medium-size molecules, and microbes. Lethality in the experimental and control group were 5.2 and 16.6% respectively.

The circular dichroism spectra of liquid-crystalline dispersions formed of double-stranded DNA molecules were calculated. It was found that the amplitude and sing of the anomalous band in these spectra in the region of absorption of nitrous bases depend on the size of dispersed particles, the pitch of their cholesterol helix and the sign of its spatial winding. The theoretical calculations are compared with experimental data characterizing the anomalous optical properties of liquid-crystalline DNA dispersions and synthetic polynucleotides formed as a result of phase elimination in aqueous salt solutions of polyethyleneglycol. The theoretically calculated circular dichroism spectra of liquid-crystalline DNA dispersions agree with the circular dichroism spectra of these dispersions observed experimentally.