Cascade showers in the NEVOD Cherenkov water detector

A technique for measuring the cascade shower energy in the NEVOD Cherenkov water detector with a spatial lattice of quasi-spherical modules is discussed. The technique allows the number of cascade particles that move near the shower axis to be reconstructed on the basis of analysis of response amplitudes of triggered photomultiplier tubes. The technique of cascade-curve reconstruction was applied to cascade showers generated by near-horizontal high-energy muons extracted by means of the DECOR coordinate-tracking detector arranged around the Cherenkov water detector. The first results of measuring the energy spectrum of cascade showers of 10–1000 GeV are presented.     

Preparation and physicochemical characterization of novel chlorambucil-loaded nanoparticles of poly(butylcyanoacrylate)

The aim of the present study is the preparation and physicochemical characterization of chlorambucil-loaded poly(butylcyanoacrylate) nanoparticles. Chlorambucil is a lipophilic drug, which is used clinically against chronic lymphocytic leukemia, lymphomas, and other types of malignant diseases. However, the chlorambucil use is limited by its chemical instability and toxic side effects. A promising approach to circumvent these drawbacks is the entrapment of chlorambucil in a suitable nanosized carrier. Toward this goal, poly(butylcyanoacrylate) nanoparticles meet the requirements for a drug carrier system due to their biocompatibility, biodegradability, low toxicity, and ability to overcome the multidrug resistance in cancer cells. We prepared chlorambucil-loaded poly(butylcyanoacrylate) nanoparticles, which are characterized for chemical composition, particle size, drug content, and drug release. It is expected that the utilization of poly(butylcyanoacrylate) nanoparticles as a drug carrier system will pave the way toward more effective use of chlorambucil in the treatment of cancer.     

Solid-phase mechanochemical incorporation of a spin label into cellulose

Samples of cellulose labeled with stable nitroxyl radicals were prepared by mechanochemical synthesis. The samples were studied by IR and EPR spectroscopies, X-ray phase analysis, and electron microscopy. The EPR spectral patterns indicate a uniform distribution of “grafted” paramagnetic centers over the cellulose macromolecular chains. X-Ray diffraction patterns obtained and the results of crystallinity index calculations for the samples showed that strong bonding of spin labels causes changes in the cellulose structure up to nearly complete amorphization of the material. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1127–1130, May, 2005.     

1H and13C NMR study of complexes of nickel(II) with water and saturated alcohols

Journal of Structural Chemistry -     

Study of coatings based on titanium oxides and oxynitrides using a set of methods

A set of methods has been applied to study the properties of titanium oxide and oxynitride coatings on steel. It is established that the coatings consist of two phases with a nanocrystalline and an amorphous structure with a high proportion (～50 %) of grain boundaries; anatase is the dominant crystalline phase. The obtained results can be applied in the development of coatings for stents as well as for manufacturing hydrogen accumulators.     

Study of cascade showers generated by near-horizontal muons in the water Cherenkov detector with a dense array of optical modules

The method for reconstructing the cascade curve by the Cherenkov radiation in water of the NEVOD detector with a dense spatial array of optical modules is discussed. Cascades are generated by near-horizontal muons which are separated by the DECOR coordinate detector. The cascade curves and the cascade energy spectrum measured in an ～8000-hour measurement series are presented.     

Investigating the energy, angular, and temporal characteristics of forbush effects registered by the URAGAN muon hodoscope

The results from analyzing variations in the flux of cosmic ray muons during Forbush effects (FEs) registered by the URAGAN muon hodoscope over the period 2005–2009 are presented. The dependences of the amplitudes for reductions in the intensity of the cosmic ray muon flux on the energy of primary particles in energy ranges higher than 10 GeV were obtained. Their changes upon different phases of Forbush effect development were investigated. The local anisotropy vectors were calculated on the basis of spatial-angular variations in the muon flux. Correlations between the parameters of physical properties in the near heloiosphere related to the Forbush effects and the characteristics of muon flux variations were analyzed.     

Effect of nickel doping on the photocatalytic activity of ZnO thin films under UV and visible light

Nanostructured ZnO thin films with different concentrations of Ni²⁺ doping (0, 1, 5, 10 and 15 wt.%) are prepared by the sol-gel method for the first time. The thin films are prepared from zinc acetate, 2-methoxyethanol and monoethanolamine on glass substrates by using dip coating method. The films comprise of ZnO nanocrystallites with hexagonal crystal structure, as revealed by X-ray diffraction. The film surface is with characteristic ganglia-like structure as observed by Scanning Electron Microscopy. Furthermore, the Ni-doped films are tested with respect to the photocatalysis in aqueous solutions of malachite green upon UV-light illumination, visible light and in darkness. The initial concentration of malachite green and the amount of catalyst are varied during the experiments. It is found that increasing of the amount of Ni²⁺ ions with respect to ZnO generally lowers the photocatalytic activity in comparison with the pure ZnO films. Nevertheless, all films exhibit a substantial activity under both, UV and visible light and in darkness as well, which is promising for the development of new ZnO photocatalysts by the sol-gel method.