East European Journal of Physics

5

Authors: P. I. Gladkikh, A. A. Kalamaiko, I. M. Karnaukhov, A. O. Mytsykov, A. Y. Zelinsky

NESTOR is the hard X-ray source that is under commissioning at NSC KIPT. NESTOR based on the Compton scattering of laser photons on relativistic electrons. The structure of the facility can be represented as the following components: a linear accelerator, a transport channel, a storage ring, and a laser-optical system. Electrons are stored in the storage ring for energy of 40-200 MeV. Inevitable alignment errors of magnetic elements are strongly effect on the beam dynamics in the storage ring. These errors lead to a shift of the equilibrium orbit relative to the ideal one. Significant shift of the equilibrium orbit could lead to loss of the beam on physical apertures. Transverse sizes of electron and laser beams are only few tens of microns at the interaction point. The shift of electron beam at the interaction point could greatly complicate the operation adjustment of storage ring without sufficient beam position diagnostic system. This article presents the simulation results of the efficiency of electron beam accumulation in the NESTOR storage ring. Also, this article is devoted to electron beam dynamics due to alignment errors of magnetic element in the ring.

7

Authors: A. E. Kokorev, V. M. Trusova, K. O. Vus, U. K. Tarabara, G. P. Gorbenko

Amyloid fibrils are highly ordered insoluble protein aggregates that are involved in molecular etiology of a number of severe disorders, including Alzheimer's, Parkinson’s and prion’s diseases, some types of systemic amyloidosis, etc. One of the most effective approaches to detecting the amyloid fibrils is based on monitoring the spectral behavior of specific fluorescent dye Thioflavin T (ThT). Using the molecular docking and molecular dynamics tools, such as PatchDock, FireDock, CreateFibril and GROMACS, the model of twisted K-peptide fibril that supposedly represent the core region of lysozyme amyloid fibrils, has been constructed and analyzed. The effect of fibril twisting angle on the binding characteristics of ThT has been evaluated. The results obtained strongly suggest that ThT specificity for the twisted ribbon fibril polymorphs is primarily determined by the curvature effects rather than amino acid composition of fibril grooveswhich accomodate ThT molecule.

8

Authors: Yu. V. Kulish, E. V. Rybachuk

It is shown that an integral corresponding to the contribution of one particle to equal-time commutator of quantized scalar fields diverges in a reality, contrary to usual assumption that this integral vanishes. It means that commutator of scalar fields does not vanish for space-like intervals between the field coordinates. In relation with this divergence the generalization of the Klein-Gordon equation is considered. The generalized equation is presented as products of the operators for the Klein-Gordon equation with different masses. The solutions of derived homogeneous equations are sums of fields, corresponding to particles with the same values of the spin, the electric charge, the parities, but with different masses. Such particles are grouped into the kinds (or families, or dynasties) with members which are the particle generations. The commutator of fields for the kinds of particles can be presented as sum of the products of the commutators for one particle and the definite coefficients. The sums of these coefficients for all the generation equal zero. The sums of the products of these coefficients and the particle masses to some powers equal zero too, i.e., for these coefficients some relations exist. In consequence of these relations the commutators of the fields for the particle generations vanish on space-like intervals. Thus, the locality (the microcausality) is valid for the fields of the particle kinds. It is possible if the number of the generations is greater than two.

11

Authors: V. B. Ivanskyi, O. N. Letuchyy, А. N. Orobinskyi, V. E. Ostrovskykh, H. V. Siroko

The energy and pulse height spectrums after passage of neutron radiation through samples of materialsmost often used to protect against neutron radiation (paraffin, paraffin with boric acid, paraffin with boric acid and lead, polyethylene, polyethylene with boron and boron carbide) are measured using a PuBe neutron source using a NEMUS spectrometer on Bonner spheres with 3He -counter. The values of linear attenuation coefficients and neutron relaxation lengths in these materials, neutron spectra for these materials are given. The percentage of neutrons in the energy subbands is determined according to the radiation weighting factor. The neutron flux density, the ambient dose equivalent power, the absorbed dose rate in the neutron radiation air, the transition coefficients from the neutron fluence to the ambient dose equivalent and average neutron radiation energy are measured. Calculation of energy spectrum, basic characteristics of neutron radiation and extended uncertainties is performed by the MAXED (maximum entropy and deconvolution), applying the Bayes theorem, method using the UMG_3.3 software.

12

Authors: V. Trusova, G. Gorbenko, U. Tarabara, K. Vus, O. Ryzhova

The protolytic and partition equilibria of the indicator dyes in the model lipid and protein-lipid systems have been analyzed. A methodological approach has been developed allowing the partition coefficients of the protonated and deprotonated dye forms to be derived from the spectrophotometric measurements. The partitioning of the indicator dye bromothymol blue into the model bilayer membranes composed of phosphatidylcholine and cardiolipin (9:1, mol:mol) has been examined. The partition coefficient of the protonated dye species into a lipid phase has been found to be 5 orders of magnitude higher than that of the deprotonated dye form. This effect has been interpreted in terms of the differences in the charge distribution over the protonated and deprotonated dye ions, preventing the hydrophobic dye-lipid interactions in the latter case. The reduction of the bromothymol blue partitioning into lipid bilayer in the presence of hemoglobin has been attributed to the protein-induced changes in the structure and physicochemical characteristics of the interfacial membrane region. In the practical aspect, the obtained findings may prove of significance in the design of hemosome-based blood substitutes and elucidating the role of hemoglobin in the molecular etiology of the amyloid disorders, particularly, Alzheimer's disease.