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Study of cobalt ferrite nanosuspensions for low-frequency ferromagnetic hyperthermia

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Particuology 2008年第5期6卷 322-333页

作者： Bronislav E.Kashevsky vladimir E.Agabekov Sergei B.Kashevsky Katsiaryna A.Kekalo Elena Yu.Manina igor v.prokhorov vladimir S.Ulashchik A.v.Luikov Heat and Mass Transfer Institute Belarus Academy of Sciences P.Brovka Str.15Minsk 220072Belarus Institute of Chemistry of New Materials Belarus Academy of SciencesSkoriny Str.36Minsk 220141Belarus Institute of Physiology Belarus Academy of SciencesAkademicheskaiy Str.28Minsk 220072Belarus

High-coercive cobalt ferrite nanoparticles were synthesized and studied for magnetic hyperthermia by direct injection of their suspension into a tumor and application of a strong audio-frequency magnetic field for heating. Physical （dynamic magnetic hysteresis and heat generation in both liquid and solid dispersions）, biological （toxicity and penetration of particles in therapeutic quantities into mouse tumor tissue） as well as other properties of the particles were studied. A model was developed to describe the magnetodynamics in suspensions of magnetic nanoclusters with an account for both Brownian and regular rotations, to provide understanding of observed phenomena. The experimental and theoretical techniques developed have formed a basis for controllable synthesis of the magnetic nanoparticles for low-frequency heat generation in medical and other applications.

关键词： Cobalt ferrite nanoparticles Magnetic suspensions Dynamic magnetic hysteresis Medical hyperthermia

Cortical hem signaling center: functions, development, and potential implications for evolution and brain disorders

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Neural Regeneration Research 2025年第4期20卷 1079-1080页

作者： victor v.Chizhikov igor Y.Iskusnykh Department of Anatomy and Neurobiology University of Tennessee Health Science CenterMemphisTNUSA

Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical *** such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in *** cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)*** cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-valle-Anton and Borrell,2022).

关键词： epithelium Figure center

Anomalous Laterally Stressed Kinetically Trapped DNA Surface Conformations

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Nano-Micro Letters 2021年第8期13卷 263-280页

作者： valery v.prokhorov Nikolay A.Barinov Kirill A.Prusakov Evgeniy v.Dubrovin Maxim D.Frank-Kamenetskii Dmitry v.Klinov Federal Research and Clinical Center of Physical-Chemical Medicine Malaya Pirogovskaya1aMoscow 119435Russian Federation A.N.Frumkin Institute of Physical Chemistry and Electrochemistry RASLeninsky prospect Moscow 199071 Russian Federation 3 Moscow Institute of Physics and TechnologyInstitutskiy per.9Dolgoprudny141700 MoscowRussian Federation Lomonosov Moscow State University Leninskie gory1-2Moscow 119991Russian Federation Department of Biomedical Engineering Boston University44 Cummington MallBoston MA02215USA

Up to now,the DNA molecule adsorbed on a surface was believed to always preserve its native *** belief implies a negligible contribution of lateral surface forces during and after DNA adsorption although their impact has never been ***-resolution atomic force microscopy was used to observe that stiff DNA molecules kinetically trapped on monomolecular films comprising one-dimensional periodically charged lamellar templates as a single layer or as a sublayer are oversaturated by sharp discontinuous kinks and can also be locally melted and *** argue that kink/anti-kink pairs are induced by an overcritical lateral bending stress(>30 pNnm)inevitable for the highly anisotropic 1D-1D electrostatic interaction of DNA and underlying rows of positive surface *** addition,the unexpected kink-inducing mechanical instability in the shape of the template-directed DNA confined between the positively charged lamellar sides is observed indicating the strong impact of *** previously reported anomalously low values of the persistence length of the surface-adsorbed DNA are explained by the impact of the surface-induced low-scale *** sites of the local melting and supercoiling are convincingly introduced as other lateral stress-induced structural DNA anomalies by establishing a link with DNA high-force *** results open up the study in the completely unexplored area of the principally anomalous kinetically trapped DNA surface conformations in which the DNA local mechanical response to the surface-induced spatially modulated lateral electrostatic stress is essentially *** underlying rich and complex in-plane nonlinear physics acts at the nanoscale beyond the scope of applicability of the worm-like chain approximation.

关键词： DNA surface conformations Kinetic trapping Lateral stress Periodically charged surface DNA kinks

Acoustic Shock Emission in a Collision of a Drop with Water Surface

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Fluid Dynamics & Materials Processing 2020年第4期16卷 737-746页

作者： v.E.prokhorov Ishlinsky Institute for Problems in Mechanics RAS Moscow119526Russia

The collision of droplets with a water surface is being actively developed in the interests of many applied problems—transfer of matter through the ocean-atmosphere boundary,underwater acoustic noise of the marine environment,measurement of precipitation intensity,various technologies,and much *** of the research priorities is acoustic radiation,in particular,shock sound arising at the moment a drop contacts the *** impact of the drop is preceded by processes that affect the shape of the drop,because of which it noticeably deviates from the spherical *** a result,the final(contact)velocity changes–one of the most important parameters of *** study of the listed factors is carried out in this work by means of broadband acoustic measurements and high-speed video recording.

关键词： Droplet impact acoustic emission shape final velocity crosscorrelation

Audio-frequency heating of particulate magnetic systems

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China Particuology 2007年第1期5卷 84-92页

作者： B.E. Kashevsky I.v. prokhorov S.B. Kashevsky A.v. Luikov Heat and Mass Transfer Institute Belarus Academy of Sciences P. Brovka str. 15 Minsk 220072 Belarus

This paper presents theoretical and experimental studies on the magnetodynamics and energy dissipation in suspensions of small ferromagnetic particles with magnetic hysteresis and mechanical mobility in an AC magnetic field. Energy absorption by particles suspended in a solid, liquid or gas environment and subjected to high frequency magnetic fields is of great interest for cancer treatment by hyperthermia, chemical technology, biotechnology and smart materials science. Sub-micron needle-like γ-Fe2O3 particles dispersed in liquid were subjected in this study to a 430 Hz magnetic field with an intensity of up to 10^5 A/m. Dynamic magnetization loops were measured in parallel to the energy dissipated in the samples. Combined magnetomechanical dynamics of particle dispersions was simulated by using a chain-of-spheres model allowing for incoherent magnetic field reversal. In liquid dispersions, within the kilohertz frequency range, the mechanical mobility of particles does not interfere with their hysteretic magnetic reversal that makes heat release comparable to that observed with solids; for instance, in the present study using γ-Fe2O3 particles in liquid subjected to 10^4 Hz field exhibited heat release rates from 250 up to 600W oer 1 cm^3 of the dry oarticle content.

关键词： AC magnetic field Particulate materials Audio-frequency heating

Microheterogeneity of the Koupol Deposit Fahlores as a Reflection of Changing of Physicochemical Parameters of the Ore-Forming Solution

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Journal of Earth Science 2013年第2期24卷 179-187页

作者： igor'v Kemkin Raisa A Kemkina Far East Geological Institute Far Eastern Branch of the Russian Academy of Sciences Far East Federal University

New data on a zonal structure of the Koupol deposit fahlores grains are given, and features of their chemism are shown. The fahlores chemical composition within the zones evolves from essentially arsenious （Fe-tennantite and Zn-tennantite）, through mixed fahlores （Zn-tennantitetetrahedrite arsenious and Zn-tennantite-tetrahedrite antimonous）, to essential antimonous （Ag-bearing Zn-tetrahedrite）. varying chemical composition manifested as mineralogical-geochemical zonation of the fahlores grains is caused by changes of physicochemical conditions of the ore forming process during the time.

关键词： fahlore mineralogical-geochemical zonation physicochemical condition Koupol deposit.

Comparative geochemical study of the cherty rocks of the Taukha terrane(Sikhote-Alin)and its paleogeodynamic significance

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Acta Geochimica 2020年第4期39卷 539-560页

作者： igor v.Kemkin Raisa A.Kemkina Far East Geological Institute Far Eastern Branch of Russian Academy of SciencesProspect 100-Letiya Vladivostoka159VladivostokRussia 690022 Far Eastern Federal University Soukhanova Street8VladivostokRussia 690950

The article presents the results of a comparative geochemical study of cherts and siliceous-clayey rocks composing the tectono-sedimentary complexes of various structural levels of the Taukha terrain of the Sikhote-Alin Late Jurassic-Early Cretaceous accretionary *** data obtained show that the same-aged parts of the crosssections of the cherty-terrigenous sequences of the terrane lower and middle structural levels are characterized by significantly different contents and distribution patterns of major petrogenic oxides,trace,and rare-earth elements due to their accumulation in various facies of oceanic *** set of geochemical data indicates that the formation of both tectono-sedimentary complexes was carried out differently,gradually replacing each others’facies oceanic zones,and started in the near-spreading ridge area,then in the pelagial,and completed in the continental-margin deposition *** on the time interval of the facies conditions changing for each complex(i.e.,time of transition from one facies zone to another),the speeds of a paleo-oceanic plate motion(and,correspondingly,the speeds of spreading)for individual intervals of the Jurassic were *** in the spreading speeds at various sites of a paleorift zone caused the turning of a paleocontinent margin contour and spreading ridge axis at the perpendicular position,which in turn caused change of the geodynamic mode on the eastern margin of the PaleoAsian continent at the Jurassic-Cretaceous transition.

关键词： Geochemistry Radiolarian cherts Deposition environment Paleo-Pacific plate Sikhote-Alin

Influence of Pt/Pd state on ceria-based support in CO oxidation

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Journal of Rare Earths 2023年第12期41卷 1963-1968,I0005页

作者： igor v.Zagaynov Elena Yu.Liberman Alexander v.Naumkin A.A.Baikov Institute of Metallurgy and Materials Science MoscowRussia D.I.Mendeleev University of Chemical Technology of Russia MoscowRussia A.N.Nesmeyanov Institute of Organoelement Compounds MoscowRussia

Noble metal(M:Pt,Pd,PtPd) supported on ceria system catalysts were *** oxidized and reduced forms of the active component were examined in CO *** catalysts become more active after a reduction pretreatment,which shifts the temperature of CO *** of the data obtained from characterization techniques indicates that the strong interaction of metal ions with the support prevent the reduction of the initial MO_(x)to metallic *** formation of M-ceria interfaces efficiently boosts the oxygen activation during CO oxidation,leading to the formation of chemisorbed O on M and the regeneration of the ceria lattice oxygen,thus greatly improving the catalytic performance.

关键词： Ceria Platinum Palladium CO oxidation Rare earths

Heat Transfer and Fluid Flow over a Single Disk in a Fluid Rotating as a Rigid Body

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Journal of Thermal Science 2004年第3期13卷 279-282页

作者： igor v. SHEvCHUK Matthias H. BUSCHMANN Institute of Engineering Thermophysics Ukrainian National Academy of Sciences 2a Zhelyabov St. Kiev 03057 UkraineInstitute of Fluid Mechanics Dresden University of Technology 01062 Dresden Germany

Laminar heat transfer problem is analyzed for a disk rotating with the angular speed ωin a co-rotating fluid (with the angular speed Ω). The fluid is swirled in accordance with a forced-vortex law, it rotates as a solid body at β= Ω/ω= const. Radial variation of the disk’s surface temperature follows a power law. An exact numerical solution of the problem is obtained basing on the self-similar profiles of the local temperature of fluid, its static pressure and velocity components. Numerical computations were done at the Prandtl numbers Pr = 1(?)0.71. It is shown that with increasing βboth radial and tangential components of shear stresses decrease, and to zero value at β= 1. Nusselt number is practically constant at β= 0(?) 0.3 (and even has a point of a maximum in this region); Nu decrease noticeably for larger βvalues.

关键词： rotating disk heat transfer fluid flow Nusselt number swirl.