Frequency dependence of magnetothermal properties for magnetic fluid and magnetically functionalized implants

Heating of the magnetic nanoparticles in AC magnetic field is the effect promising for application in medicine. The mechanisms of heating in AC-magnetic field implies nontrivial dependence of the power dissipated by magnetic nanoparticles on frequency. With the use of a reconfigurable experimental setup, this frequency-dependent magnetic heating was measured on two characteristic examples: the magnetite nanoparticles conventionally used in medicine and polymer coating with micrometer sized magnetite particles. The saturation of the heating power with frequency is shown that is more pronounced for the second case of microparticles

Decreasing water concentration in the Uragan-3M device with UHF discharge

Uragan-3M device vacuum chamber is a cylinder with volume of 70 m³. Between the operation series, it is opened to the atmosphere for scientific and technical works. The problem of high water vapour concentration in the residual gas appears each time the chamber is closed and pumped. Effective water vapour removal can be achieved by baking the vacuum chamber walls at high temperatures (200…400°C) or increasing atomic hydrogen flow produced by the wall conditioning discharge in the plasma confining volume, as far as Н₂О detachment speed should be higher than adhesion. It's not technically possible to heat Uragan-3M device vacuum chamber. Room temperature of the vacuum chamber walls is not an obstacle for an UHF discharge with high enough plasma density (8∙10¹⁰ cm⁻³).Вакуумная камера установки Ураган-3М представляет собой цилиндр из нержавеющей стали объемом ~70 м³. Периодически вакуумная камера вскрывается для напуска атмосферного давления с целью проведения научных и технических работ. После ее закрытия и откачки до высокого вакуума, появляется проблема, связанная с высокой концентрацией воды в остаточном газе. Для эффективного удаления паров воды обычно используется прогрев стенок камеры при температуре 200…400°С. Альтернативой является поддержание плазменного разряда в водороде, обеспечивающего поток атомарного водорода на стенку. На установке Ураган-3М прогрев камеры технически не возможен, поэтому использовался плазменный СВЧ-разряд с достаточной величиной плотности плазмы (8∙10¹⁰ см⁻³).Вакуумна камера установки Ураган-3М являє собою циліндр з нержавіючої сталі об'ємом ~70 м³. Періодично вакуумна камера відкривається для напуску атмосферного тиску для проведення наукових і технічних робіт. Після її закриття та відкачування з'являється проблема, пов'язана з високою концентрацією води в залишковому газі. Для ефективного видалення парів води необхідно підтримувати стінки камери при високій температурі (200…400°С). Альтернативою є підтримка плазмового розряду у водні, що забезпечує потік атомарного водню на стінку. На установці Ураган-3М прогрів камери технічно не можливий, тому кімнатну температуру стінок камери доводиться компенсувати достатньою величиною щільності плазми (8∙10¹⁰ см⁻³) НВЧ-розряду

Usage of three-halfturn antenna at the Uragan-3M device

Unshielded THT antenna is successfully used: (i) for heating of plasma prepared by the frame antenna pulse, (ii) for making an initial plasma with low density ~10¹⁰ cm⁻³ for further frame antenna operation, (iii) for independent generation and heating plasma at low magnetic fields B₀ <0.7 T and (iv) for mutual operation with frame antenna. In the last scenario both antennas contribute to plasma heating.Неэкранированная трехполувитковая антенна успешно используется: (i) для нагрева плазмы, подготовленной импульсом рамочной антенны; (ii) для создания начальной плазмы низкой плотности ~ 10¹⁰ см⁻³ для дальнейшей работы рамочной антенны; (iii) для независимого создания и нагрева плазмы в магнитных полях B₀ <0,7 Тл; (iv) для совместной роботы с рамочной антенной (в этом случае обе антенны дают вклад в нагрев плазмы).Неекранована трьохнапіввиткова антена успішно використовується: (i) для нагріву плазми, підготовленої імпульсом рамкової антени; (ii) для створення початкової плазми з низькою густиною ~ 10¹⁰ см⁻³ для подальшої роботи рамкової антени; (iii) для незалежного створення та нагріву плазми в магнітних полях B₀ <0,7 Тл; (iv) для взаємної роботи з рамковою антеною (у цьому випадку обидві антени роблять внесок до нагріву плазми)

Transition to the improved confinement mode in torsatron U-3M in range of rare collision frequencies

Transition to the mode of improved plasma confinement in U-3M facility earlier was discussed in works [1-3]. In these studies discussed the various processes in the confinement volume and in the peripheral plasma that accompany the transition process. Study of plasma confinement and process of transition into the mode of improved confinement just at rare collisions between plasma particles is very important because future fusion reactor based on a toroidal magnetic trap will operate under plasma parameters with rare collision frequencies (“banana” mode). The peculiarity of experiments on torsatron U-3M is that they are conducted at small density ne ≤ 2×10^12 cm^-3 and, thereby, the frequency of collisions in the confinement area is in the "banana" mode [4]. And herewith, time of collisions is essentially smaller (up to several orders for electrons and up to the order for ions) than the lifetime of plasma particles. It ensures maxwellization of distribution function and possibility to compare the obtained results with data from other experiments. The objective of this work is to study the main regularity of transition into the mode of improved confinement. Also it is interesting to compare the results with data from other facilities

Analysis of single-nucleotide polymorphisms associated with an increased risk of immune reconstitution inflammatory syndrome in patients with tuberculosis and HIV

Tuberculosis immune reconstitution inflammatory syndrome (TB-IRIS) is the development or progression of tuberculosis associated with restoration of active immune response to mycobacteria following the initiation of antiretroviral therapy in HIVinfected patients. The incidence of TB-IRIS is 18% with mortality reaching 2%. Investigation of TB-IRIS in Russia is very important, since the prevalence of TB coinfection is common among HIV-infected patients; in addition to that, HIV is often detected at late stages characterized by severe immunosuppression, which increases the risk of TB-IRIS. This review focuses on single-nucleotide polymorphisms and some other genetic factors associated with an increased risk of TB-IRIS. © 2021, Dynasty Publishing House. All rights reserved

X-ray spectroscopic study of nonequilibrium laser produced plasma in porous targets of low average density

New experimental results on laser irradiation (I$\,{\le}\,$10$^{14}$ W/cm$^{2}$, $\lambda$ = 1.053 $\mu$m) of low-density fibrous agar are presented. X-ray spectrometers with spherically bent mica crystals were used for measuring with high spectral resolution the line spectra of multicharge ions. Detailed analysis of the measured spectra made it possible to determine the temperature of electrons and ions in hot plasma created in laser irradiated low-density samples in dependence on average material density and average intensity within a focal spot. Significant difference between ion and electron temperatures is found for the whole range of experimental conditions

Frequency dependence of magnetothermal properties for magnetic fluid and magnetically functionalized implants

Heating of the magnetic nanoparticles in AC magnetic field is the effect promising for application in medicine. The mechanisms of heating in AC-magnetic field implies nontrivial dependence of the power dissipated by magnetic nanoparticles on frequency. With the use of a reconfigurable experimental setup, this frequency-dependent magnetic heating was measured on two characteristic examples: the magnetite nanoparticles conventionally used in medicine and polymer coating with micrometer sized magnetite particles. The saturation of the heating power with frequency is shown that is more pronounced for the second case of microparticles

Frequency dependence of magnetothermal properties for magnetic fluid and magnetically functionalized implants

Heating of the magnetic nanoparticles in AC magnetic field is the effect promising for application in medicine. The mechanisms of heating in AC-magnetic field implies nontrivial dependence of the power dissipated by magnetic nanoparticles on frequency. With the use of a reconfigurable experimental setup, this frequency-dependent magnetic heating was measured on two characteristic examples: the magnetite nanoparticles conventionally used in medicine and polymer coating with micrometer sized magnetite particles. The saturation of the heating power with frequency is shown that is more pronounced for the second case of microparticles