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23 results on '"Repetsky, S. P."'

2. The energy spectrum and the electrical conductivity of graphene with substitution impurity

Author

Repetsky, S. P., Vyshyvana, I. G., Kruchinin, S. P., Melnyk, R. M., and Polishchuk, A. P.

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

The effect of substitution atoms on the energy spectrum and the electrical conductivity of graphene was investigated in a Lifshitz one-electron tight-binding model. It is established that the ordering of impurity atoms results in a gap in the energy spectrum of electrons whose width depends on the order parameter and on the magnitude of the scattering potential. It is shown that if the order parameter is close to its maximum value, there are peaks associated with localized impurity states on the energy curve of the electron states density at the edges of the energy gap. At the electron concentration at which the Fermi level enters the gap region, the electrical conductivity is zero, and the metal-dielectric transition occurs. If the Fermi level falls in the region of the energy band, the electron relaxation time and electrical conductivity tend to infinity when the order parameter reaches its maximum value. The analytical calculations of the electron density and of the electrical conductivity of graphene, made in the limiting case of weak scattering, are compared with the results of the numerical calculations for different scattering potentials., Comment: 14 pages, 3 figures

Published
2020
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10. Models of Nanocomplexes Based on C60 Fullerene for Creation of Anticancer and Anti-Inflammatory Agents.

Author

Repetsky, S. P., Andrusyshyn, A. V., Kuznetsova, G. M., Melnyk, R. M., and Rybalchenko, V. K.

Subjects
ANTI-inflammatory agents, ANTINEOPLASTIC agents, MOLECULAR orbitals, INTEGRATED software, TREATMENT effectiveness
Abstract

Based on the quantum-chemical method of molecular orbitals, implemented in the Gaussian 09w software package, a method of modelling nanocomplexes for creation of antitumour and anti-inflammatory medicines is developed. The object of study is a complex of C60 fullerene and antitumour agent 1-(4-C1-benzyl)-3-C1-4-(CF3-phenylamino)-1H-pyrrole-2,5-dione (abbreviated as MI-1). Each detached part, C60 and MI-1, has a therapeutic effect. The main antitumour and anti-inflammatory action relies on MI-1 compound. It is found that the nanocomplex of C60 fullerene with MI-1 is stable at human-body temperature. The nanocomplex is able to serve as a vehicle of medicines to the tumour tissue and dissociate in the tumour due to its low pH (higher acidity) compared to healthy tissue and exhibit therapeutic properties of individual components. [ABSTRACT FROM AUTHOR]

Published
2021

11. Models of Nanostructures Based on Titanium Dioxide TiO2 for Transport of Biologically Active Compounds.

Author

Repetsky, S. P., Andrusyshyn, A. V., Kuznetsova, G. M., Melnyk, R. M., and Rybalchenko, V. K.

Subjects
BIOACTIVE compounds, TITANIUM dioxide, BIOLOGICAL transport, DENSITY functional theory, ANTINEOPLASTIC agents, PYRROLE derivatives
Abstract

Using the density functional theory to quantum-mechanical calculations in the Gaussian 09w software package, antitumor drug of target action on the basis of titanium dioxide and pyrrole derivative 1-(4-Cl-benzyl)-3-Cl-4-(CF3 - fenylamino)-1H-pyrrol-2.5-dione (chemical compound MI-1) is simulated. MI1 compound has high therapeutic potential as an antitumor agent. Titanium dioxide is insoluble in the stomach and used as a filler and sheath of medicines. There is reason to use TiO2 to transport MI-1 to the site of the affected tissue for targeted effect on colorectal tumours. Computational tools of the software package reveal that titanium dioxide TiO2 together with MI-1 forms a stable nanocomplex. Upon penetration into the tumour tissue, due to the low pH in comparison with healthy tissue, a significant proportion of these nanocomplexes will be dissociate with the separation titanium dioxide and MI-1 compound that will be have a therapeutic effect on damage tissue. [ABSTRACT FROM AUTHOR]

Published
2020

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