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Губанова, Елизавета Михайловна

Организационные подразделения

Организационная единица

Инженерно-физический институт биомедицины

Цель ИФИБ и стратегия развития – это подготовка высококвалифицированных кадров на базе передовых исследований и разработок новых перспективных методов и материалов в области инженерно-физической биомедицины. Занятие лидерских позиций в биомедицинских технологиях XXI века и внедрение их в образовательный процесс, что отвечает решению практикоориентированной задачи мирового уровня – диагностике и терапии на клеточном уровне социально-значимых заболеваний человека.

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Елизавета Михайловна

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Ferromagnetic resonance spectra of linear magnetosome chains
(2024) Gubanova, E. M.; Usov, N. A.; Губанова, Елизавета Михайловна; Усов, Николай Александрович
The ferromagnetic resonance (FMR) spectra of oriented and non-oriented assemblies of linear magnetosome chains are calculated by solving the stochastic Landauў??Lifshitz equation. The dependence of the shape of the FMR spectrum of a dilute assembly of chains on the particle diameter, the number of particles in a chain, the distance between the centers of neighboring particles, the mutual orientation of the cubic axes of particle anisotropy, and the value of the magnetic damping constant is studied. It is shown that FMR spectra of non-oriented chain assemblies depend on the average particle diameter at a fixed thickness of the lipid magnetosome membrane, as well as on the value of the magnetic damping constant. At the same time, they are practically independent of the number N p of particles in the chain under the condition N p ў?? 10. The FMR spectra of non-oriented assemblies of magnetosome chains are compared with that of random clusters of interacting spherical magnetite nanoparticles. The shape of FMR spectra of both assemblies is shown to differ appreciably even at sufficiently large values of filling density of random clusters.
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Heating ability of elongated magnetic nanoparticles
(2021) Gubanova, E. M.; Usov, N. A.; Oleinikov, V. A.; Губанова, Елизавета Михайловна; Усов, Николай Александрович; Олейников, Владимир Александрович
Low-frequency hysteresis loops and specific absorption rate (SAR) of various assemblies of elongated spheroidal magnetite nanoparticles have been calculated for a range of particle semiaxis ratios a/b = 1.0-3.0. The SAR of a dilute randomly oriented assembly of magnetite nanoparticles in an alternating magnetic field of moderate frequency, f = 300 kHz, and amplitude H0 = 100-200 Oe is shown to decrease significantly with an increase in the aspect ratio of nanoparticles. In addition, there is a narrowing and shift of the intervals of optimal particle diameters towards smaller particle sizes. However, the orientation of a dilute assembly of elongated nanoparticles in a magnetic field leads to an almost twofold increase in SAR at the same frequency and amplitude of the alternating magnetic field, the range of optimal particle diameters remaining unchanged. The effect of the magneto-dipole interaction on the SAR of a dilute assembly of oriented clusters of elongated magnetite nanoparticles has also been investigated depending on the volume fraction of nanoparticles in a cluster. It has been found that the SAR of the assembly of oriented clusters decreases by approximately an order of magnitude with an increase in the volume fraction of nanoparticles in a cluster in the range of 0.04-0.2.
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Specific absorption rate of assembly of magnetic nanoparticles with uniaxial anisotropy
(2020) Wei, Z. H.; Usov, N. A.; Gubanova, E. M.; Усов, Николай Александрович; Губанова, Елизавета Михайловна
© Published under licence by IOP Publishing Ltd.Specific absorption rate of superparamagnetic nanoparticles with uniaxial magnetic anisotropy has been calculated both for dilute assembly and for assembly of nanoparticle clusters with various filling factors using numerical simulation. The optimal particle diameters at which the specific absorption rate of assembly reaches a maximum have been obtained depending on the value of the uniaxial anisotropy constant. The optimal particle diameters are found to shift to smaller values with an increase in the anisotropy constant. The range of optimal diameters decreases simultaneously. The specific absorption rate decreases also as a function of cluster filling factor, but the optimal particle diameters remain almost unchanged.
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Application of Magnetosomes in Magnetic Hyperthermia
(2020) Usov, N. A.; Gubanova, E. M.; Усов, Николай Александрович; Губанова, Елизавета Михайловна
Nanoparticles, specifically magnetosomes, synthesized in nature by magnetotactic bacteria, are very promising to be usedin magnetic hyperthermia in cancer treatment. In this work, using the solution of the stochastic Landau-Lifshitz equation, we calculate the specific absorption rate (SAR) in an alternating (AC) magnetic field of assemblies of magnetosome chains depending on the particle sizeD, the distance between particles in a chaina, and the angle of the applied magnetic field with respect to the chain axis. The dependence of SAR on thea/Dratio is shown to have a bell-shaped form with a pronounced maximum. For a dilute oriented chain assembly with optimally chosena/Dratio, a strong magneto-dipole interaction between the chain particles leads to an almost rectangular hysteresis loop, and to large SAR values in the order of 400-450 W/g at moderate frequenciesf= 300 kHz and small magnetic field amplitudesH(0)= 50-100 Oe. The maximum SAR value only weakly depends on the diameter of the nanoparticles and the length of the chain. However, a significant decrease in SAR occurs in a dense chain assembly due to the strong magneto-dipole interaction of nanoparticles of different chains.
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Quasistatic hysteresis loops of magnetic nanoparticles in a rotating magnetic field
(2020) Usov, N. A.; Gubanova, E. M.; Epstein, N. B.; Belyaeva, G. A.; Oleinikov, V. A.; Усов, Николай Александрович; Губанова, Елизавета Михайловна; Эпштейн, Наталья Борисовна; Олейников, Владимир Александрович
© 2019Quasistatic hysteresis loops of a single-domain magnetic nanoparticle with uniaxial anisotropy in a rotating magnetic field have been calculated. Magnetic hysteresis is shown to exist only in a limited range of reduced magnetic field amplitudes, 0.5 < h0 < 1, where h0 = H0/Ha, H0 is the amplitude of the rotating magnetic field, Ha being the particle anisotropy field. An analytical formula is obtained for the particle coercive force as a function of the reduced field amplitude. In the domain h0 < 0.5 the magnetization reversal of a particle is impossible, since the final energy barrier exists between the potential wells of the particle for all orientations of applied magnetic field. On the other hand, in the domain h0 > 1 the total energy of the nanoparticle has a single energy minimum, so that there is no magnetic hysteresis. Quasistatic hysteresis loops of a randomly oriented assembly of non interacting nanoparticles in a rotating magnetic field are also obtained.
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The heating of magnetic nanoparticles in a rotating magnetic field
(2020) Serebryakova, O. N.; Usov, N. A.; Gubanova, E. M.; Усов, Николай Александрович; Губанова, Елизавета Михайловна
© 2019, © 2019 Taylor & Francis.The specific absorption rate of magnetic nanoparticles in a rotating magnetic field has been calculated taking into account both thermal fluctuations of the particle magnetic moments and strong magneto-dipole interactions in nanoparticle clusters with various filling factors. For an assembly of interacting superparamagnetic nanoparticles, the maximal values of the specific absorption rate in a rotating magnetic field are found to be 30–40% greater than that in alternating magnetic field. In addition, for the given filling factor and magnetic field amplitude in rotating magnetic field the nanoparticles in a wider range of diameters can effectively contribute to the energy absorption process. Therefore, the use of rotating magnetic field seems preferable in magnetic nanoparticle hyperthermia.
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Magnetostatic properties of assembly of magnetic vortices
(2020) Bautin, V. A.; Perov, N. S.; Rytov, R. A.; Gubanova, E. M.; Usov, N. A.; Губанова, Елизавета Михайловна; Усов, Николай Александрович
© 2019The ultrasonic oscillation of a macroscopic sample in a viscous liquid is used to create magnetic particles of FeCo alloy with an average diameter D ~100 nm. The FeCo particles obtained have a high specific saturation magnetization, Ms = 1960 emu/cm3, close to that of a bulk sample. The hysteresis loop of a magneto-polymer composite prepared from FeCo particles shows low coercive force and a remanent magnetization close to zero. The magnetic saturation of the magnetic composite samples is achieved in a sufficiently strong magnetic field, H = 6.5 kOe. The hysteresis loop features of the magnetic composite have been explained by means of the numerical simulation of the quasistatic hysteresis loops of non-oriented dilute assemblies of spheroidal FeCo particles with various aspect ratios.
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Heating ability of magnetic nanoparticles with cubic and combined anisotropy
(2019) Nesmeyanov, Mikhail S.; Usov, Nikolai A.; Gubanova, Elizaveta M.; Epshtein, Natalia B.; Усов, Николай Александрович; Губанова, Елизавета Михайловна; Эпштейн, Наталья Борисовна
The low frequency hysteresis loops and specific absorption rate (SAR) of assemblies of magnetite nanoparticles with cubic anisotropy are calculated in the diameter range of D = 20-60 nm taking into account both thermal fluctuations of the particle magnetic moments and strong magneto-dipole interaction in assemblies of fractal-like clusters of nanoparticles. Similar calculations are also performed for assemblies of slightly elongated magnetite nanoparticles having combined magnetic anisotropy. A substantial dependence of the SAR on the nanoparticle diameter is obtained for all cases investigated. Due to the influence of the magneto-dipole interaction, the SAR of fractal clusters of nanoparticles decreases considerably in comparison with that for weakly interacting nanoparticles. However, the ability of magnetic nanoparticle assemblies to generate heat can be improved if the nanoparticles are covered by nonmagnetic shells of appreciable thickness.
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Dynamics of particles with cubic magnetic anisotropy in a viscous liquid
(2022) Rytov, R. A.; Gubanova, E. M.; Usov, N. A.; Губанова, Елизавета Михайловна; Усов, Николай Александрович
© 2021 Elsevier B.V.We calculated the specific absorption rate (SAR) and relaxation time of a dilute assembly of spherical iron nanoparticles with cubic anisotropy distributed in a viscous liquid. The behavior of unit magnetization vector was investigated by the solution of stochastic Landau–Lifshitz equation. The spatial orientation of magnetic nanoparticle was determined by the set of stochastic equations for multiple particle directors. The particle viscous and magnetic magnetization reversal modes are revealed at low and sufficiently high amplitudes of alternating magnetic field, respectively. The SAR of iron nanoparticle assembly is shown to exceed significantly that of iron oxide nanoparticles with uniaxial anisotropy at the same amplitudes and frequencies of applied magnetic field. The linear response theory is shown to be valid only at small magnetic field amplitudes, H0 ≤ 50–70 Oe.