Papers by Alexander pushkarchuk
A Numerical Investigation on Flow Characteristics in Helical Pipes Using Lattice Boltzmann Method
The Proceedings of the International Conference on Nuclear Engineering (ICONE), 2019
Chemotherapy is one of the main treatment options for cancer, but it is usually accompanied with ... more Chemotherapy is one of the main treatment options for cancer, but it is usually accompanied with negative side effects. The classical drugs combination with synergistic adjuvants can be the solution to this problem, allowing reducing therapeutic dose. Elucidating the mechanism of adjuvant action is of key importance for selection of the optimal agent. Here we examine the system drug-adjuvant to explain observed effect in practice. We used the first line drug – cisplatin. Morpholinium and 4-methylpiperazinium 4,5-dichloro isothiazol-3-carboxylates were selected as adjuvants. The study of cisplatin – adjuvant system was carried out by quantum chemical modeling with DFT method. It turned out that adjuvants form conjugates with cisplatin that leads to relocation of frontier molecular orbitals as well as increase of conjugate’s dipole moment. It results in change of the character of interaction with DNA and increase of bioactivity of system. The data obtained are the basis for expanding ...
The influence of the nano-size fullerides C 60(FeCp 2) 2, C 60 (NiCp 2) 2 and its derivatives on the cell proliferation in vitro
Effect of Adjuvants of the Isotiazole Series in Combination with Cisplatin in Chemotherapy of Neuroepithelial Tumors: Experiment, Modeling, Hypothesis
SSRN Electronic Journal
Materials possessing excellent bacterial toxicity, while presenting low cytotoxicity to human cel... more Materials possessing excellent bacterial toxicity, while presenting low cytotoxicity to human cells, are strong candidates for biomaterials applications. In this study, we present the fabrication of a nanocomposite containing poly(N-vinylcarbazole) (PVK) and graphene (G) in solutions and thin films. Highly dispersed PVK-G (97-3 w/w%) solutions in various organic and aqueous solvents were prepared by solution mixing and sonication methods. The thermal properties and morphology of the new composite were analyzed using thermal gravimetry analysis (TGA) and atomic force microscopy (AFM), respectively. PVK-G films were immobilized onto indium tin oxide (ITO) substrates via electrodeposition. AFM was used to characterize the resulting topography of the nanocomposite thin films, while cyclic voltammetry and UV-vis were used to monitor their successful electrodeposition. The antimicrobial properties of the electrodeposited PVK-G films and solution-based PVK-G were investigated against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis). Microbial growth after exposure to the nanocomposite, metabolic assay and live-dead assay of the bacterial solutions exposed to PVK-G presented fewer viable and active bacteria than those exposed to pure PVK or pure graphene solutions. The PVK-G film inhibited about 80% of biofilm surface coverage whereas the PVK-and G-modified surfaces allowed biofilm formation over almost the whole coated surface (i.e. >80%). The biocompatibility of the prepared PVK-G solutions on NIH 3T3 cells was evaluated using the MTS cell proliferation assay. A 24 h exposure of the PVK-G nanocomposite to the NIH 3T3 cells presented ∼80% cell survival.
Simulation of the spin properties of the 13C atoms nearest to the single [NV]− center in a nanodiamond by the density-functional method
Journal of Engineering Physics and Thermophysics
ABSTRACT A quantum-chemical simulation of the spin properties of diamond nanocrystals with [NV]− ... more ABSTRACT A quantum-chemical simulation of the spin properties of diamond nanocrystals with [NV]− centers passivated with hydrogen atoms has been carried out. The concrete atoms from the nearest and farthest surroundings of the [NV]− center, which contribute to the formation of the spin density causing hyperfine splitting, were determined.
Journal of Applied Spectroscopy
We have used the density functional method to model the atomic and electronic structure of diamon... more We have used the density functional method to model the atomic and electronic structure of diamond nanocrystals passivated by hydrogen atoms and either not containing defects or containing a single [NV]-center. We have shown that in all cases, after relaxation the nanocrystals are formed as diamond-like structures.
Kramers-degenerated NV+1 13 C spin systems in diamond: analytical description
Saratov Fall Meeting 2012: Optical Technologies in Biophysics and Medicine XIV; and Laser Physics and Photonics XIV, 2013
ABSTRACT Spin systems consisted of single electronic spin S=1 of the NV center and nearby nuclear... more ABSTRACT Spin systems consisted of single electronic spin S=1 of the NV center and nearby nuclear spins I=1/2 of 13C atoms disposed in diamond lattice near the center can be used as a small register of a quantum computer or as a sensor of a magnetic field. At odd number of nuclear spins eigenvalues of the spin systems at zero external magnetic field are at least twofold degenerated (Kramers degeneration) due to time reversal invariance of the spin Hamiltonian. This degeneracy is lifted only by external magnetic field regardless of the presence of any electric (crystal) field which can also lift the degeneracy thus hindering measurement of the magnetic field. Therefore, the Kramers-degenerated spin systems can be very perspective for measurement of a local magnetic field by the NV-based single-spin quantum magnetometer. Here, we are considering analytically the simplest Kramers-degenerated spin system NV+113C consisting of a single electron spin S=1 of the NV сenter coupled by hyperfine interaction with a single nuclear spin I=1/2 of 13C atom disposed in arbitrary site of diamond lattice. Simple approximate analytical expressions are obtained for eigenvalues and eigenstates of the spin system.
Band Structure Variation of the (0001) Face for Corundum during Formation and Hydration
physica status solidi (b), 1985
Twelfth International Workshop on Nanodesign Technology and Computer Simulations, 2008
Modeling of atomic structure and distribution of spin density for the NV center formed close to t... more Modeling of atomic structure and distribution of spin density for the NV center formed close to the surface (111) of nano-diamond has been carried out using quantum-chemical PM3 and DFT methods. The case is considered where the nitrogen atom of NV center is located in the near-surface atomic layer of a face (111). The relaxation of surface atoms relative to the initial position results in N atom to be shifted from the cluster center parallel to the <111> direction by 0.16Å, and C atoms belonging to the surface layer are also shifted parallel to the <111> direction to the center by 0.18Å. As this takes place, C-C and C-N distances between relaxed atoms decrease and a graphite-like structure is formed on a (111) crystal face. In the structure, the N atom and C atoms nearest to it lay practically in the same plane. The formed C-N bond can be considered as one-and-a-half bond. It has been found that unlike the NV center in bulk diamond for which the spin density is located mainly on the carbon atoms, being nearest neighbors to the vacancy of the NV center, in the case of the NV center located in immediate proximity to the surface, there is a redistribution of spin density resulting in its major allocation in three C atoms, the nearest neighbors to the N atom, that form the first atomic layer of a surface (111) of nano-crystal.
Ab Initio Modeling of Nanodiamonds with Single [Nv]− Centers
Physics, Chemistry and Application of Nanostructures - Reviews and Short Notes to Nanomeeting-2005, 2005
Rare gases in silicon interstices
ABSTRACT
Proceedings of International Conference Nanomeeting 2015, 2015
The problem of nature and thermal stability of the bond between nanodiamond core and perfluorobut... more The problem of nature and thermal stability of the bond between nanodiamond core and perfluorobuthyl radical is addressed with the aid of near edge X-ray absorption fine structure spectroscopy and quantum chemistry calculations.
Hyperfine Interactions in the Carbon Cluster C 291 H 172 NV Hosting NV Center
Physics, Chemistry and Applications of Nanostructures, 2013
ABSTRACT We present the results of quantum chemistry simulation of hyperfine interactions (hfi) b... more ABSTRACT We present the results of quantum chemistry simulation of hyperfine interactions (hfi) between electronic spin of single NV center and arbitrary disposed 13C nuclear spins in the NV-hosting H-terminated cluster C291NVH172. The calculated hfi matrices are used in spin- Hamiltonians to simulate available experimental observations.
DFT Modeling of Structural, Electronic and Spin Properties of Nickel–Nitrogen-Containing (NE8) Center in Nanodiamond
ABSTRACT
Spin systems consisted of single electronic spin of the NV center in diamond and few proximal 13 ... more Spin systems consisted of single electronic spin of the NV center in diamond and few proximal 13 C nuclei spins which are considered now as a perspective candidate for room-temperature implementation of a quantum computer register with optical access are studied by spin-Hamiltonian method using parameters of hyperfine NV-13 C interactions taken from EPR measurements on NV ensemble and from ab initio (DFT) simulation of carbon clusters containing NV centers. Experimental data on ODMR spectra and spin echo modulation obtained on single NV+n 13 C centers are interpreted without fitting parameters.
Elastic Modules and Low-Frequency Oscillations of Isolated Carbon Nanotubes
Proceedings of SPIE - The International Society for Optical Engineering
Modeling of atomic structure and distribution of spin density for the NV center formed close to t... more Modeling of atomic structure and distribution of spin density for the NV center formed close to the surface (111) of nano-diamond has been carried out using quantum-chemical PM3 and DFT methods. The case is considered where the nitrogen atom of NV center is located in the near-surface atomic layer of a face (111). The relaxation of surface atoms relative to the initial position results in N atom to be shifted from the cluster center parallel to the direction by 0.16Å, and C atoms belonging to the surface layer are also shifted parallel to the direction to the center by 0.18Å. As this takes place, C-C and C-N distances between relaxed atoms decrease and a graphite-like structure is formed on a (111) crystal face. In the structure, the N atom and C atoms nearest to it lay practically in the same plane. The formed CN bond can be considered as one-and-a-half bond. It has been found that unlike the NV center in bulk diamond for which the spin density is located mainly on the carbon atoms...
Atomic and Spin Structure of Single NV--Centers Near Nanodiamond Surface
Modeling of the atomic structure and spin properties of a NV--center formed close to a (111) surf... more Modeling of the atomic structure and spin properties of a NV--center formed close to a (111) surface of nano-diamond has been carried out by using quantum-chemical PM3 and DFT methods. We consider the case where the nitrogen atom of the NV--center is located in the near-subsurface atomic layer of a (111) facet. The relaxations of the surface atoms relative to their initial position are studied. The calculated spin densities for the considered clusters were compared with those ones for the clusters having the NV--center in the bulk. It was confirmed that for the NV--center in the bulk the spin density is located mainly on C atoms being the nearest neighbors to the vacancy. In the case of nanodiamonds there is a redistribution of the spin density resulting in its major allocation at the three C atoms being the nearest neighbors to the N atom and forming just the first atomic layer of the (111) surface.
Individual NV Centers Near Surface of Nanostructured Diamond: DFT Simulation
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Papers by Alexander pushkarchuk