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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krasikov A. A., Balaev D. A., Balaev A. D., Stolyar S. V., Yaroslavtsev R. N., Iskhakov R. S.
Заглавие : Separating the contributions of the magnetic subsystems in antiferromagnetic ferrihydrite nanoparticles by analyzing the magnetization in fields of up to 250 kOe
Колич.характеристики :8 с
Место публикации : J. Magn. Magn. Mater. - 2024. - Vol. 592. - Ст.171781. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2024.171781. - ISSN 18734766 (eISSN)
Примечания : Cited References: 84. - This study was supported by his work was supported by the Russian Science Foundation, project no. 22–72-00134Authors thank to D.A. Velikanov, S.V. Komogortsev for fruitful discussions
Аннотация: Contributions of different magnetic subsystems formed in the systems of synthetic ferrihydrite nanoparticles (characterized previously) with an average size of ˂d˃ ≈ 2.7 nm coated with polysaccharide arabinogalactan in different degrees have been separated by measuring the dependences of their magnetization M on magnetic field H of up to 250 kOe on vibrating sample and pulsed magnetometers. The use of a wide measuring magnetic field range has been dictated by the ambiguity in identifying a linear M(H) portion for such antiferromagnetic nanoparticle systems within the conventional field range of 60–90 kOe. The thorough analysis of the magnetization curves in the temperature range of 100–250 K has allowed the verification of the contributions of (i) uncompensated magnetic moments µun in the superparamagnetic subsystem, (ii) the subsystem of surface spins with the paramagnetic behavior, and (iii) the antiferromagnetic susceptibility of the antiferromagnetically ordered ferrihydrite particle core. As a result, a model of the magnetic state of ferrihydrite nanoparticles has been proposed and the numbers of spins corresponding to magnetic subsystems (i)–(iii) have been estimated. An average magnetic moment μun of ∼ 145 μB (μB is the Bohr magneton) per particle corresponds approximately to 30 decompensated spins of iron atoms in a particle (about 3 % of all iron atoms), which, according to the Néel’s hypothesis μun ∼ ˂d˃3/2, are localized both on the surface and in the bulk of an antiferromagnetically ordered particle. The fraction of free (paramagnetic) spins is minimal in the sample without arabinogalactan coating of the nanoparticle surface (7 %) and is attained 20 % of all iron atoms in the sample with the highest degree of spatial separation of particles. According to this estimation, paramagnetic spins are located mainly on the edges and protruding areas of particles. Most magnetic moments of iron atoms are ordered antiferromagnetically and the corresponding magnetic susceptibility of this subsystem behaves as in an antiferromagnet with the randomly distributed crystallographic axes, i.e., increases with temperature.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Karacharov A. A., Likhatski M. N., Borisov R. V., Tomashevich E. V., Vorobyev S. A., Zharkov S. M.
Заглавие : Modification of synthetic valleriite surface with gold nanoparticles: The roles of specific adsorption and zeta potential
Колич.характеристики :12 с
Место публикации : Colloid J. - 2024. - Vol. 86, Is. 1. - P.40-51. - ISSN 1061933X (ISSN), DOI 10.1134/S1061933X23601075. - ISSN 16083067 (eISSN)
Примечания : Cited References: 69. - This work was supported by the Russian Science Foundation project no. 22-13-00321
Аннотация: Layered two-dimensional materials, whose properties dramatically differ from their bulk precursors, are of great theoretical and applied importance. Recently, a layered 2D material, an analog of a natural mineral, valleriite, in which quasi-monoatomic Cu−Fe−S sheets alternate with brucite-like ones, has been prepared using a simple hydrothermal synthesis procedure. The features of the electronic structure of these materials make it possible to propose them as new materials for a wide field of applications such as (electro)photocatalysis, high-capacity batteries, etc. In this work, nanocomposite materials have been prepared via immobilization of gold nanoparticles (AuNPs) from citrate hydrosols on the surface of the synthesized valleriites having different compositions of hydroxide layers, which control the surface charge density. According to X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy-dispersive X-ray microanalysis (EDX), and selected area electron diffraction (SAED) data, AuNPs are immobilized on valleriite nanoflakes, which have lateral sizes of 150–200 nm and thicknesses of several tens of nanometers, as isolated metal nanoparticles with an average diameter of 11 nm. A small amount of aggregates indicates a high affinity of AuNPs for the valleriite surface. The amounts of immobilized gold are the same on all studied valleriites (~0.2%). This finding may be related to the simultaneous sorption of free citrate ions from the AuNP hydrosols, with these ions, according to zeta potential measurements, charging the surfaces of all studied valleriite samples to nearly the same negative value of –40 mV. According to the XPS data, the AuNPs immobilization markedly decreases the magnesium and oxygen contents on the surfaces of the synthesized valleriites due to the partial degradation/dissolution of the brucite layer. In addition, the amount of Fe3+ ions bound to OH groups decreases with a simultaneous increase in the fraction of Fe3+–O species. The TEM data have confirmed the preservation of the layered structure of valleriites after the immobilization of AuNPs.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Fedorov A. S., Eremkin E. V., Krasnov P. O., Gerasimov V. S., Agren H., Polyutov S. P.
Заглавие : A hybrid quantum–classical theory for predicting terahertz charge-transfer plasmons in metal nanoparticles on graphene
Колич.характеристики :13 с
Место публикации : J. Chem. Phys. - 2024. - Vol. 160, Is. 4. - Ст.044117. - ISSN 00219606 (ISSN), DOI 10.1063/5.0178247. - ISSN 10897690 (eISSN)
Примечания : Cited References: 61. - This study was funded by the Ministry of Science and High Education of Russian Federation, Project No. FSRZ-2023-0006. The calculations of CTPs in specific NP–graphene complexes were performed within the RSF Grant No. 23-12-20007 and the Krasnoyarsk Territorial Foundation for Support of Scientific and R & D Activities, Agreement No. 256. H. Ågren was supported by the Swedish Science Research Council on Contract No. 2022-03405
Аннотация: Metal nanoparticle (NP) complexes lying on a single-layer graphene surface are studied with a developed original hybrid quantum–classical theory using the Finite Element Method (FEM) that is computationally cheap. Our theory is based on the motivated assumption that the carrier charge density in the doped graphene does not vary significantly during the plasmon oscillations. Charge transfer plasmon (CTP) frequencies, eigenvectors, quality factors, energy loss in the NPs and in graphene, and the absorption power are aspects that are theoretically studied and numerically calculated. It is shown the CTP frequencies reside in the terahertz range and can be represented as a product of two factors: the Fermi level of graphene and the geometry of the NP complex. The energy losses in the NPs are predicted to be inversely dependent on the radius R of the nanoparticle, while the loss in graphene is proportional to R and the interparticle distance. The CTP quality factors are predicted to be in the range ~ 10 – 100. The absorption power under CTP excitation is proportional to the scalar product of the CTP dipole moment and the external electromagnetic field. The developed theory makes it possible to simulate different properties of CTPs 3–4 orders of magnitude faster compared to the original FEM or the finite-difference time domain method, providing possibilities for predicting the plasmonic properties of very large systems for different applications.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shadrin K. V., Yakovleva Yu. A., Kryukova O. V., Makarskaya G. V., Tarskikh S. V., Pyankov V. F., Pakhomova V. G., Gerasimova Yu. V., Yaroslavtsev R. N., Vorobyev S. A., Stolyar S. V.
Заглавие : Influence of arabinogalactan-coated selenium nanoparticles on the formation of free radicals in Ehrlich ascites carcinoma cells
Колич.характеристики :8 с
Место публикации : BioNanoScience. - 2024. - Vol. 14, Is. 1. - P.268-275. - ISSN 21911630 (ISSN), DOI 10.1007/s12668-023-01251-6. - ISSN 21911649 (eISSN)
Примечания : Cited References: 40
Аннотация: The antioxidant properties of selenium nanoparticles coated with arabinogalactan have been studied. The nanoparticles were characterized by transmission electron microscopy and infrared spectroscopy. Arabinogalactan-coated selenium nanoparticles were incubated together with Ehrlich ascitic carcinoma cells and then exposed to microwave radiation. The antioxidant properties of selenium nanoparticles were evaluated using chemiluminescent analysis. The viability of Ehrlich ascitic carcinoma cells under microwave irradiation and incubation with selenium nanoparticles was assessed by flow cytometry. Under conditions of exposure to experimental tumor cells of microwave radiation, the concentration of free radicals in the cells did not change. The effect of arabinogalactan-coated selenium nanoparticles on tumor cells is expressed as an increase in the delay time for the activation of the antioxidant system.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Krasikov A. A., Knyazev Yu. V., Yaroslavtsev R. N., Velikanov D. A., Mikhlin Yu. L., Volochaev M. N., Bayukov O. A., Ladygina V. P., Stolyar S. V., Iskhakov R. S.
Заглавие : Magnetic collective state formation upon tuning the interparticle interactions in ensembles of ultrafine ferrihydrite nanoparticles
Колич.характеристики :13 с
Место публикации : Nano-Struct. Nano-Objects. - 2024. - Vol. 37. - Ст.101089. - ISSN 2352507X (ISSN), DOI 10.1016/j.nanoso.2023.101089. - ISSN 23525088 (eISSN)
Примечания : Cited References: 93. - The authors thank M.N. Volochaev for the TEM investigations
Аннотация: The results of a study of the dynamic (alternating current magnetic susceptibility) and static magnetic properties, as well as 57Fe Mössbauer spectrometry and ferromagnetic resonance of two-line ferrihydrite nanoparticle systems with varying intensities of magnetic interparticle interactions are reported. The strength of the magnetic interparticle interactions has been tuned by coating (with various degrees of coating) the ferrihydrite particles (2–4 nm in size and an average size ∼2.7 nm) of the initial synthetic sample by arabinogalactan. Also, a biogenic ferrihydrite sample (an average particle size of 2-nm) with a natural organic coating was studied and it has the weakest magnetic interparticle interactions among of all the samples. Relaxation times of the particle’s magnetic moment were determined by the data of static and dynamic magnetic susceptibilities and from analysis of 57Fe Mössbauer spectrometry. Based on the temperature dependences of the relaxation times, it has been concluded that the predominantly collective processes of freezing of the particle magnetic moments occur under the action of the magnetic interparticle interactions. It is shown that an important role in these processes is played by a magnetic subsystem of the surface spins of the particles. The effect of the interplay between the surface spin and magnetic moment subsystems on the static magnetic properties (low-temperature magnetic hysteresis loops) and the parameters of the microwave absorption line under the magnetic resonance conditions is discussed.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Vorobyev S. A., Flerko M. Yu., Novikova S. A., Mazurova E. V., Tomashevich Ye. V., Likhatski M. N., Saikova S. V., Samoilo A. S., Zolotovsky N. A., Volochaev M. N.
Заглавие : Synthesis and study of superhigh-concentrated organosols of silver nanoparticles
Колич.характеристики :10 с
Место публикации : Colloid J. - 2024. - Vol. 86, Is. 2. - P.208-217. - ISSN 1061933X (ISSN), DOI 10.1134/S1061933X23601294. - ISSN 16083067 (eISSN)
Примечания : Cited References: 33. - The work was carried out with the financial support of the basic project FWES-2021-0014 of the Institute of Chemistry and Chemical Technology, Siberian Branch, Russian Academy of Sciences, and the Federal Program "Priority 2030" using the equipment of the Krasnoyarsk regional center for collective use of the Federal Research Center Krasnoyarsk Scientific Center, Siberian Branch, Russian Academy of Sciences
Аннотация: Due to their unique properties, organosols of silver nanoparticles are widely used in optical and semiconductor devices, to produce electrically and thermally conductive films, as catalysts, antibacterial materials, etc. This work proposes a simple and highly productive method for the preparation of silver organosols, which have a metal concentration as high as 1800 g/L and contain spherical nanoparticles with low polydispersity and a median size of 9.1 nm. The method consists in the initial preparation of silver nanoparticle hydrosols with a concentration of higher than 30 g/L followed by the transfer of the NPs into an organic phase of o-xylene. A set of physical research methods has been employed to study the regularities of the extraction of silver nanoparticles with o-xylene in the presence of cetyltrimethylammonium bromide (CTAB) and ethanol and to determine the optimal process conditions, under which the extraction degree is as high as 62.5%. It has been found that bromine anions contained in CTAB molecules cause the aggregation of some amount of silver nanoparticles with the formation of silver metal sediment in the aqueous phase. According to X-ray photoelectron spectroscopy data, the sediment contains bromide ions (up to 4 at %) on the particle surface. Organosols synthesized under optimal conditions are stable for more than 7 months and withstand repeated cycles of drying and redispersing. Silver organosols have been used to obtain metal films with an electrical conductivity of about 68 500 S/cm, which increases to 412 000 and 509 500 S/cm (87.8% of the electrical conductivity of bulk silver) after thermal treatment at 150 and 250°C, respectively.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bondarenko L., Baimuratova R., Dzeranov A., Pankratov D., Kicheeva A., Sushko E., Kudryasheva N., Valeev R., Tropskaya N., Dzhardimalieva G., Kydralieva K.
Заглавие : Fenton reaction-driven pro-oxidant synergy of ascorbic acid and iron oxide nanoparticles in MIL-88B(Fe)
Колич.характеристики :19 с
Место публикации : New J. Chem. - 2024. - Vol. 48, Is. 22. - P.10142-10160. - ISSN 11440546 (ISSN), DOI 10.1039/D4NJ00963K. - ISSN 13699261 (eISSN)
Примечания : Cited References: 94
Аннотация: MIL-88B, a promising Fe-based 3D porous metal–organic framework (MOF) catalyst for the Fenton reaction, requires modifications to enhance its pro-oxidant activity and enable magnetic control of the sample. This study reports the successful modification of MIL-88B with iron oxide (Fe3O4) and ascorbic acid (AA). The characterization of the crystal structure and morphology of the Fe3O4–AA MOF sample using X-ray diffraction, Raman and Mossbauer spectroscopy, and scanning electron microscopy revealed that AA facilitated the formation of magnetite with a composition approaching a stoichiometry of Fe2.96O4 while preserving the MOF structure. Specifically, in the presence of hydrogen peroxide (H2O2), Fe3O4–AA–MOF exhibited a 3-fold increase in the Fenton reaction rate for methylene blue degradation compared to the conventional homogeneous system at pH 4.5. Furthermore, Fe3O4–AA–MOF retained the antibacterial properties of AA, as evidenced by its ability to increase reactive oxygen species in luminescent marine bacterium Photobacterium phosphoreum at low concentrations while exhibiting moderate cytotoxicity. The enhanced pro-oxidant activity of the Fe3O4–AA–MOF/H2O2 system is attributed to an AA-promoted surface Fe2+/Fe3+ cycle. A possible mechanism for this system is proposed.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Yaroslavtsev R. N., Tyumentseva A.V., Velikanov D. A., Vazhenina I. G., Volochaev M. N., Stolyar S. V.
Заглавие : Fe3O4/Au nanocomposites: Characterization and cytotoxicity effects in vitro
Колич.характеристики :8 с
Место публикации : Mater. Chem. Phys. - 2024. - Vol. 322. - Ст.129524. - ISSN 02540584 (ISSN), DOI 10.1016/j.matchemphys.2024.129524. - ISSN 18793312 (eISSN)
Примечания : Cited References: 44
Аннотация: Magnetic nanocomposites containing iron oxide and gold components take great attention last years because of their relative biocompatibility and the ability to combine the magnetic properties of iron and the chemical bonding properties of gold for the possible drug delivery or diagnostics for various diseases. However, such particles have some toxicity to living cells, and the effect depends on many factors, including size, shape, the ratio of components in the composites, and the type of cells affected. And thus, the search for compositions and technologies for producing iron-gold particles with improved properties and reduced cytotoxicity remains relevant. The aim of the study was to synthesize and characterize Fe3O4/Au nanocomposites and evaluate their influence on living cells using the example of cell line HEK293. Fe3O4 nanoparticles (NPs) were synthesized by co-precipitation of Fe2+/Fe3+ water solution in alkaline conditions and then boiled with HAuCl4 in 0.1 M sodium citrate. The NPs properties were estimated by transmission electron microscopy (TEM), vibration magnetometry and ferromagnetic resonance (FMR). According to magnetometric measurements, nanoparticles are mainly in a superparamagnetic state. By fitting magnetization curves, the magnetic characteristics of nanoparticles were determined: saturation magnetization (59.3 emu/g) and magnetic anisotropy constant (K = 0.86·105 erg/cm3). The average particle size estimated from magnetic measurements was 8.7 nm. Considering the presence of a magnetically dead layer, this is in good agreement with the TEM results. The temperature dependence of the FMR linewidth was analyzed using two models. As a result, the parameters MSV and K/MS were determined. The models used showed good agreement. The values of the anisotropy constant (K = 1.06·105 erg/cm3) and the average particle size (6.8 nm) are estimated. The effect of the NPs on the HEK293 cells was studied by MTT-assay, flow cytometry and RT-PCR. The exposure with the NPs lead to a significant decrease of cell metabolic activity in HEK293 cell culture, but this effect was not accompanied by cell death. It was shown that the expression of antioxidant enzymes SOD1 and GPX1 was reduced at the mRNA stage. So the NPs synthesized may affect gene expression and metabolism of HEK293 cells, but this does not have fatal consequences for cell viability.
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Ivanova O. S., Edel'man I. S., Sventitsky E. S., Serdyuk A. A., Toropova E. S.
Заглавие : Adsorption and Catalytic Properties of Nanoparticles Fe3O4-Ag in Relation to Various Types of Organic Dyes
Коллективы : "Mechanisms of catalytic reactions", International conference, "Механизмы каталитических реакций", международная конференция, Институт катализа им. Г.К. Борескова Сибирского отделения РАН, Институт органической химии им. Н.Д. Зелинского РАН, Московский государственный университет им. М.В. Ломоносова, Сибирское отделение РАН, Центр компетенций НТИ "Водород как основа низкоуглеродной экономики"
Место публикации : XII lnternational conference "Mechanisms of catalvtic reactions": abstracts. - Novosibirsk, 2024. - Ст.PP-09. - P.174-175. - ISBN 978-5-906376-56-5
Примечания : Библиогр.: 2. - РНФ и Красноярский краевой фонд науки, проект 23-22-10025
Материалы конференции,
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Stolyar S. V., Li O. A., Vorotynov A. M., Velikanov D. A., Maksimov N. G., Iskhakov R. S., Ladygina V. P., Shokhrina A. O.
Заглавие : Studying the ferromagnetic resonance heating of an isotropic superparamagnet by the example of biogenic ferrihydrite nanoparticles
Колич.характеристики :4 с
Место публикации : Bull. Russ. Acad. Sci.: Phys. - 2024. - Vol. 88, Is. 4. - P.536-539. - ISSN 10628738 (ISSN), DOI 10.1134/S106287382370627X. - ISSN 19349432 (eISSN)
Примечания : Cited References: 10
Аннотация: Ferrihydrite nanoparticles are synthesized and characterized. The dependences of heating of powders are studied upon pumping by a high-frequency electromagnetic field on a dc magnetic field. It is shown that the experimental dependence of the temperature of particles on a dc magnetic field is consistent with the theory of ferromagnetic resonance for an isotropic superparamagnet.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ivanova O. S., Lin, Chun-Rong, Edelman I. S., Svetlitsky E. S., Sokolov A. Е., Zharkov S. M., Sukhachev A. L., Vorobyev S. A., Petrov D. A., Lin, En-Szu
Заглавие : Adsorption properties and catalytic activity of Fe3O4-Ag nanostructures
Колич.характеристики :12 с
Место публикации : Appl. Surf. Sci. - 2024. - Vol. 665. - Ст.160236. - ISSN 01694332 (ISSN), DOI 10.1016/j.apsusc.2024.160236. - ISSN 18735584 (eISSN)
Примечания : Cited References: 48. - The work is supported by the Russian Science Foundation (project no. 23-22-10025, https://rscf.ru/project/ 23-22-10025/) and by the Krasnoyarsk Regional Fund of Science and Technology Support. The electron microscopy and EDS investigations were conducted in the SFU Joint Scientific Center. Magnetic investigations were carried out in the Krasnoyarsk Regional Center of Research Equipment of Federal Research Center "Krasnoyarsk Science Center SB RAS"
Аннотация: The morphology and magnetic properties as well as adsorption capacity and catalytic activity of Fe3O4-Ag nanoparticles synthesized by the solvothermal method were studied in dependence on the duration of the thermolysis process (3, 6, and 8 h). X-ray diffraction, transmission electron microscopy, and energy-dispersive spectroscopy measurements showed that the morphology of nanoparticles changed strongly as the duration of thermolysis increased. At 6 and 8 h duration, Fe3O4 nanocrystals grow and assemble into porous spherical globules with an Ag core (samples 2 and 3). These samples demonstrate high magnetization value and very low coercivity. The adsorption capacity of nanoparticles was studied with respect to two organic dyes: cationic methylene blue (MB) and anionic Congo red (CR). The particles showed preferential adsorption of the cationic dye. High catalytic activity towards four dyes: MB, methyl orange (MO), CR, and Rhodamine C (RhC) at the presence of NaBH4 is the remarkable property of these samples. The rate constant of the catalytic reaction was 1.4 min−1. Simultaneous exposure of CR and MO dyes to nanoparticles and NaBH4 caused their irreversible 100 % degradation while in the case of MB and RhC, a transition to their leuco form occurred.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ivanova O. S., Edelman I. S., Sokolov A. Е., Svetlitsky E. S., Zharkov S. M., Sukhachev A. L., Lin Ch. R., Chen Yu. Zh.
Заглавие : Adsorption of organic dyes by Fe3O4@C, Fe3O4@C@C, and Fe3O4@SiO2 magnetic nanoparticles
Место публикации : Bull. Russ. Acad. Sci. Phys. - 2023. - Vol. 87, Is. 3. - P.338-342. - ISSN 10628738 (ISSN), DOI 10.3103/S1062873822701192. - ISSN 19349432 (eISSN)
Примечания : Cited References: 17. - This research was funded partly by the Ministry of Science and Higher Education of the Russian Federation, project FWES-2021-0035. Ch. R. Lin and Yu. Zh. Chen thank the National Science and Technology Council of Taiwan for the financial support, MOST no. 110-2112-M-153-005- and no. 108-2923-M-153-001-MY3
Аннотация: Fe3O4@C, Fe3O4@C@C, and Fe3O4@SiO2 core–shell nanoparticles are synthesized via thermal decomposition and coprecipitation. Samples are characterized via X-ray spectroscopy, transmission electron microscopy, and magnetometry. It is shown that the magnetic core of all nanoparticles is nanocrystalline and has crystal parameters corresponding to only one phase of Fe3O4, covered with a uniform shell of amorphous carbon or silicon oxide around 8 nm thick. Special attention is given to adsorption properties of the nanoparticles with respect to four dyes: Methylene blue, Congo Red, Eosin Y, and Rhodamine C. The high selectivity of Fe3O4@C nanoparticles to various dyes is revealed.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krasikov A. A., Knyazev Yu. V., Balaev D. A., Velikanov D. A., Stolyar S. V., Mikhlin Yu. L., Yaroslavtsev R. N., Iskhakov R. S.
Заглавие : Interparticle magnetic interactions and magnetic field dependence of superparamagnetic blocking temperature in ferrihydrite nanoparticle powder systems
Место публикации : Phys. B: Condens. Matter. - 2023. - Vol. 660. - Ст.414901. - ISSN 09214526 (ISSN), DOI 10.1016/j.physb.2023.414901. - ISSN 18732135 (eISSN)
Примечания : Cited References: 66. - This study was supported by his work was supported by the Russian Science Foundation, project no. 22-72-00134
Аннотация: In this study, nanoparticles of initial synthetic ferrihydrite have been coated with arabinogalactan. The synthesized series of samples with different degrees of coverage of particles has been characterized by X-ray photoelectron spectroscopy, Mossbauer spectroscopy, transmission electron microscopy and magnetometry. The superparamagnetic blocking temperature decreases monotonically with an increase in the degree of coverage of ferrihydrite particles, which is unambiguously related to the different role of the interparticle magnetic interactions in the investigated powder systems. Analysis of the field dependence of the blocking temperature within the random anisotropy model has shown that an increase in the degree of coverage of ferrihydrite particles leads to a decrease in the size of a cluster in which the behaviors of the nanoparticle magnetic moments are correlated. The results obtained have shown the possibility of effective control of the strength of magnetic interparticle interactions in powder ferrihydrite systems by coating nanoparticles with arabinogalactan.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Samoshkina Yu. E., Rautskii M. V., Neznakhin D. S., Stepanova E. A., Edelman I. S., Chou, Hsiung
Заглавие : Particles–matrix bond in ZnCoO:H and ZnCoAlO:H films: Issues of magnetism and spin injection
Место публикации : Materials. - 2023. - Vol. 16, Is. 10. - Ст.3659. - ISSN 19961944 (eISSN), DOI 10.3390/ma16103659
Примечания : Cited References: 45. - This work was supported by the Russian Science Foundation [grant number 21-72-00061]
Аннотация: ZnCoO:H and ZnCoAlO:H films were synthesized by radio frequency magnetron sputtering in a (1 − x)Ar + xH2 mixed atmosphere with x = 0.2–0.5. The films contain different amounts of metallic Co particles (from 7.6% and higher) ~4–7 nm in size. The magnetic and magneto-optical (MO) behavior of the films was analyzed in combination with their structural data. The samples exhibit high values of magnetization (up to 377 emu/cm3) and MO response at room temperature. Two situations are considered: (1) the film magnetism is associated only with isolated metal particles and (2) magnetism is present both in the oxide matrix and in metal inclusions. It has been established that the formation mechanism of the magnetic structure of ZnO:Co2+ is due to the spin-polarized conduction electrons of metal particles and zinc vacancies. It was also found that in the presence of two magnetic components in the films, these components are exchange-coupled. In this case, the exchange coupling generates a high spin polarization of the films. The spin-dependent transport properties of the samples have been studied. A high value of the negative magnetoresistance of the films at room temperature (~4%) was found. This behavior was explained in terms of the giant magnetoresistance model. Thus, the ZnCoO:H and ZnCoAlO:H films with high spin polarization can be considered as sources of spin injection.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krasikov A. A., Balaev D. A.
Заглавие : Analysis of magnetization processes in antiferromagnetic nanoparticles in strong pulse fields (Brief review)
Коллективы : Eurasian Symposium “Trends in Magnetism”
Место публикации : J. Exp. Theor. Phys. - 2023. - Vol. 136, Is. 1. - P.97-105. - ISSN 10637761 (ISSN), DOI 10.1134/S1063776123010132. - ISSN 10906509 (eISSN)
Примечания : Cited References: 43. - The authors are grateful to V.L. Kirillov for synthesis of a set of NiO samples, O.N. Mart’yanov for cooperation and discussion of results for NiO nanoparticles, V.P. Ladygina for synthesis of nanoferrihydrite, S.V. Stolyar and R.S. Iskhakov for cooperation and discussion of results for ferrihydrite, and A.D. Balaev, K.A. Shaikhutdinov, and S.I. Popkov for the decisive contribution to the realization of pulse field setup
Аннотация: We present a brief review of investigations and analysis of magnetization curves M(H) for NiO and ferrihydrite antiferromagnetic nanoparticles in external fields up to 250 kOe. For correct interpretation of magnetic properties of systems of antiferromagnetic nanoparticles, it is important to take into account the segment of M(H) dependences, which corresponds to high fields (exceeding 100 kOe). We analyze the regularities in the formation of additional magnetic subsystems in antiferromagnetically ordered nanoparticles due to the influence of size effects. These additional subsystems (the ferromagnetic subsystem associated with uncompensated magnetic moment and the subsystem of surface free spins) are estimated quantitatively. It is shown that antiferromagnetic nanoparticles with a size of 5 nm acquire the properties of “nanomagnets,” which are not inferior to those for iron-oxide ferromagnetic nanoparticles of the same size.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrov D. A., Edelman I. S., Thakur A., Thakur P., Sukhachev A. L., Ovchinnikov S. G.
Заглавие : Correlation between magnetic and electric properties in the series of CoxZn1 – xFe2O4 nanoparticles
Место публикации : JETP Lett. - 2023. - Vol. 117, Is. 10. - P.765-768. - ISSN 00213640 (ISSN), DOI 10.1134/S0021364023600969. - ISSN 10906487 (eISSN)
Примечания : Cited References: 18. - The author(s) A. Thakir and O. Thakir would like to acknowledge the support provided under the The Department of Science and Technology-Funding for Improvemnt of Science and Technology (DST-FIST) Grant # SR/FST/PS-I/2018/48 of Gouverment of India. Autors also wish to acknowledge Gurujal, an initiative with district administration Gurugram for financial assistance vide project # 176 Gurujal dated September 10, 2019, Amity Incubation grant from The Ministry of Electronics and Information Technology: (Meity) under Technology Incubation and Development of Enterpreneurs (TIDE 2.0) program and the startup Nanolattice X
Аннотация: Magnetization dependences of CoxZnl1 – xFe2O4 nanoparticles (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) synthesized with the citrate precursor technique on an external magnetic field and temperature are presented. Ferrimagnetic order in nanoparticles with x ≥ 0.2 appeared at temperatures, T, exceeding room temperature, and in nanoparticles with x = 0 and 0.1 at T near 100 K. The saturation magnetization, Ms, remnant magnetization, Mr, and the coercive force, Hc, increase with x increase and the temperature decrease. Ms reached very high value: Ms of NPs with x = 0.5 equals to 106.6 emu/g at 100 K while, according to the literature data, Ms of stoichiometric bulk Co ferrite equals to 90 emu/g at 4.2 K. Correlations between concentration dependences of magnetic and electric properties has been revealed and explained qualitatively.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kicheeva A. G., Sushko E. S., Bondarenko L. S., Kydralieva K. A., Pankratov D. A., Tropskaya N. S., Dzeranov A. A., Dzhardimalieva G. I., Zarrelli M., Kudryasheva N. S.
Заглавие : Functionalized magnetite nanoparticles: Characterization, bioeffects, and role of reactive oxygen species in unicellular and enzymatic systems
Место публикации : Int. J. Mol. Sci. - 2023. - Vol. 24, Is. 2. - Ст.1133. - ISSN 16616596 (ISSN), DOI 10.3390/ijms24021133. - ISSN 14220067 (eISSN)
Примечания : Cited References: 125. - This research was funded by Russian Science Foundation, N 22-73-10222
Аннотация: The current study evaluates the role of reactive oxygen species (ROS) in bioeffects of magnetite nanoparticles (MNPs), such as bare (Fe3O4), humic acids (Fe3O4-HA), and 3-aminopropyltriethoxysilane (Fe3O4-APTES) modified MNPs. Mössbauer spectroscopy was used to identify the local surrounding for Fe atom/ions and the depth of modification for MNPs. It was found that the Fe3O4-HA MNPs contain the smallest, whereas the Fe3O4-APTES MNPs contain the largest amount of Fe2+ ions. Bioluminescent cellular and enzymatic assays were applied to monitor the toxicity and anti-(pro-)oxidant activity of MNPs. The contents of ROS were determined by a chemiluminescence luminol assay evaluating the correlations with toxicity/anti-(pro-)oxidant coefficients. Toxic effects of modified MNPs were found at higher concentrations (10−2 g/L); they were related to ROS storage in bacterial suspensions. MNPs stimulated ROS production by the bacteria in a wide concentration range (10−15–1 g/L). Under the conditions of model oxidative stress and higher concentrations of MNPs (10−4 g/L), the bacterial bioassay revealed prooxidant activity of all three MNP types, with corresponding decay of ROS content. Bioluminescence enzymatic assay did not show any sensitivity to MNPs, with negligible change in ROS content. The results clearly indicate that cell-membrane processes are responsible for the bioeffects and bacterial ROS generation, confirming the ferroptosis phenomenon based on iron-initiated cell-membrane lipid peroxidation.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ivanova O. S., Edelman I. S., Lin, Chun-Rong, Svetlitsky E. S., Sokolov A. Е., Lukyanenko, Kirill A., Sukhachev A. L., Shestakov N. P., Chen, Ying-Zhen, Spivakov, Aleksandr A.
Заглавие : Core–shell Fe3O4@C nanoparticles for the organic dye adsorption and targeted magneto-mechanical destruction of Ehrlich ascites carcinoma cells
Место публикации : Materials. - 2023. - Vol. 16, Is. 1. - Ст.23. - ISSN 19961944 (eISSN), DOI 10.3390/ma16010023
Примечания : Cited References: 65. - This research was funded partly by the Ministry of Science and Higher Education of the Russian Federation, project FWES-2021-0035. C.-R.L., Y.-Z.C. and A.A.S. thank the National Science and Technology Council of Taiwan for the financial support, Grants NSTC № 108-2923-M-153-001-MY3 and № 110-2112-M-153-005-. Magnetic investigations were carried out in the Center for Collective Use of the Krasnoyarsk Regional Center of Research Equipment of Federal Research Center “Krasnoyarsk Science Center SB RAS”
Аннотация: The morphology, structure, and magnetic properties of Fe3O4 and Fe3O4@C nanoparticles, as well their effectiveness for organic dye adsorption and targeted destruction of carcinoma cells, were studied. The nanoparticles exhibited a high magnetic saturation value (79.4 and 63.8 emu/g, correspondingly) to facilitate magnetic separation. It has been shown that surface properties play a key role in the adsorption process. Both types of organic dyes—cationic (Rhodomine C) and anionic (Congo Red and Eosine)—were well adsorbed by the Fe3O4 nanoparticles’ surface, and the adsorption process was described by the polymolecular adsorption model with a maximum adsorption capacity of 58, 22, and 14 mg/g for Congo Red, Eosine, and Rhodomine C, correspondingly. In this case, the kinetic data were described well by the pseudo-first-order model. Carbon-coated particles selectively adsorbed only cationic dyes, and the adsorption process for Methylene Blue was described by the Freundlich model, with a maximum adsorption capacity of 14 mg/g. For the case of Rhodomine C, the adsorption isotherm has a polymolecular character with a maximum adsorption capacity of 34 mg/g. To realize the targeted destruction of the carcinoma cells, the Fe3O4@C nanoparticles were functionalized with aptamers, and an experiment on the Ehrlich ascetic carcinoma cells’ destruction was carried out successively using a low-frequency alternating magnetic field. The number of cells destroyed as a result of their interaction with Fe3O4@C nanoparticles in an alternating magnetic field was 27%, compared with the number of naturally dead control cells of 6%.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Knyazev Yu. V., Balaev D. A., Skorobogatov S. A., Velikanov D. A., Bayukov O. A., Stolyar S. V., Yaroslavtsev R. N., Iskhakov R. S.
Заглавие : Spin dynamics in ensembles of ultrafine ferrihydrite nanoparticles
Место публикации : Phys. Rev. B. - 2023. - Vol. 107, Is. 11. - Ст.115413. - ISSN 24699950 (ISSN), DOI 10.1103/PhysRevB.107.115413. - ISSN 24699969 (eISSN)
Примечания : Cited References: 66. - The electron microscopy study and ac susceptibility measurements were carried out on the equipment of the Krasnoyarsk Territorial Center for Collective Use, Krasnoyarsk Scientific Center, Siberian Branch of the Russian Academy of Sciences. This study was supported by the Russian Science Foundation, Project No. 21-72-00025 Tuning the Magnetic Properties of Ultrafine Biocompatible Ferrihydrite Nanoparticles through Interparticle Interactions [66]
Аннотация: Features of the spin dynamics in ensembles of interacting (FH-chem) and weakly interacting (FH-coated) magnetic ultrasmall (‹d› ∼ 2 nm) ferrihydrite nanoparticles have been explored. The dc and ac magnetic susceptibilities [χ'(T ) and χ''(T )] of the investigated samples have been thoroughly measured in a weak magnetic field (2 Oe) around the temperatures of superparamagnetic blocking of the nanoparticle magnetic moments (19 and 50.4 K for FH-coated and FH-chem, respectively, according to the dc magnetization data). It has been shown that the magnetic interactions between nanoparticles induce the formation of the cluster spin-glass state below the superparamagnetic blocking temperature (Tg = 18 and 49.5 K for FH-coated and FH-chem, respectively). It has been found that coating of nanoparticles increases the critical scaling index from zν = 5.9 (FH-chem) to zν = 8.0 (FH-coated). This indicates a general slowdown of the dynamics of correlated spins, which is also expressed as an increase in relaxation time τ0 after switching on the interparticle interactions. We attribute this phenomenon to a consequence of a change in the volume of correlated spins with the increasing size of a cluster of interacting nanoparticles. It has been demonstrated using the simulated χ''(T ) dependence that the dissipation of the magnetic energy occurs in two independent stages. The first stage is directly related to the blocking of the nanoparticle magnetic moments, while the second stage reflects the spin-glass behavior of surface spins and depends strongly on the intensity of the interparticle interactions.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Samoshkina Yu. E., Edelman I. S., Chou, Hsiung, Petrov D. A., Zharkov S. M., Neznakhin, Dmitry, Stepanova, Elena, Stepanov, Andrey
Заглавие : Magnetic circular dichroism of Co nanoparticles localized in matrices of various types
Место публикации : Materialia. - 2023. - Vol. 28. - Ст.101759. - ISSN 25891529 (eISSN), DOI 10.1016/j.mtla.2023.101759
Примечания : Cited References: 28. - This work was supported by the Russian Science Foundation [grant number 21-72-00061]. Electron microscopic studies were carried out in the laboratory of electron microscopy of the Joint Scientific Center of the Siberian Federal University
Аннотация: Magnetic and magneto-optical properties of cobalt nanoparticles (Co-NPs) dispersed in a transparent dielectric SiO2 and semiconductor ZnO matrices have been investigated. Field and temperature dependences of the samples magnetization showed the typical behavior of an ensemble of superparamagnetic particles with a blocking temperature near and below room temperature. The spectroscopy of magnetic circular dichroism (MCD) in the visible and near-infrared light ranges has revealed a significant difference between the behavior of the Co-NPs and a solid Co film. It has been found that the MCD spectrum shape for the Co-NPs does not depend on the matrix type. The room temperature magneto-optical activity of the Co-NPs in the different matrices has been estimated as an indicator for practical applications.
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