Longitudinal Ultrasound Velocity and Attenuation in Isotopically Enriched Cadmium

The results of the acoustic-properties’ study of high-purity (>99.999%) cadmium enriched to 66.4% with the isotope ¹⁰⁶Cd and to 82.2% with the isotope ¹¹⁶Cd are presented for the temperature range of 77–300 K. Isotopic effects are observed in the temperature dependence of the 50 MHz ultrasound propagation velocity and attenuation. A comparison of the sound velocity data for the ¹⁰⁶Cd and ¹¹⁶Cd samples has revealed a first-order isotopic effect with a characteristic linear dependence on the isotopes’ masses difference, and it determines the phonon-spectrum change caused by the isotope composition. Measuring the attenuation of the longitudinal ultrasound made it possible to detect a second-order isotopic effect with a quadratic dependence on the isotopes’ masses difference. The quadratic effect is due to a disordered isotope distribution, and it causes an additional relaxation mechanism for phonon scattering.Представлены результаты исследования акустических свойств высокочистого (>99,999%) кадмия, обогащённого до 66,4% по изотопу ¹⁰⁶Cd и до 82,2% по изотопу ¹¹⁶Сd, в температурной области 77–300 К. Изотопические эффекты наблюдались на температурной зависимости скорости распространения и затухания ультразвука частотой 50 МГц. Сравнение данных для скорости звука образцов ¹⁰⁶Cd и ¹¹⁶Сd выявляет изотопический эффект первого порядка с характерной линейной зависимостью от разности масс изотопов и определяет изменение фононного спектра с изотопным составом. Измерение затухания продольного ультразвука позволило обнаружить изотопический эффект второго порядка с квадратичной зависимостью от разности масс изотопов. Квадратичный эффект связан с неупорядоченным распределением изотопов и обусловливает дополнительный релаксационный механизм рассеяния фононов.Представлено результати дослідження акустичних властивостей високочистого (>99,999%) кадмію, збагаченого до 66,4% ізотопом ¹⁰⁶Cd і до 82,2% ізотопом ¹¹⁶Сd, у температурній області 77–300 К. Ізотопічні ефекти спостерігалися на температурній залежності швидкости поширення та згасання ультразвуку частотою у 50 МГц. Порівняння даних для швидкости звуку зразків ¹⁰⁶Cd і ¹¹⁶Сd виявляє ізотопічний ефект першого порядку з характерною лінійною залежністю від ріжниці мас ізотопів і визначає зміну фононного спектру з ізотопним складом. Міряння згасання поздовжнього ультразвуку уможливило виявити ізотопічний ефект другого порядку з квадратичною залежністю від ріжниці мас ізотопів. Квадратичний ефект пов’язаний з неупорядкованим розподілом ізотопів і зумовлює додатковий релаксаційний механізм розсіяння фононів

Plastic Flow in Two-Dimensional Solids

A time-dependent Ginzburg-Landau model of plastic deformation in two-dimensional solids is presented. The fundamental dynamic variables are the displacement field \bi u and the lattice velocity {\bi v}=\p {\bi u}/\p t. Damping is assumed to arise from the shear viscosity in the momentum equation. The elastic energy density is a periodic function of the shear and tetragonal strains, which enables formation of slips at large strains. In this work we neglect defects such as vacancies, interstitials, or grain boundaries. The simplest slip consists of two edge dislocations with opposite Burgers vectors. The formation energy of a slip is minimized if its orientation is parallel or perpendicular to the flow in simple shear deformation and if it makes angles of $\pm \pi/4$ with respect to the stretched direction in uniaxial stretching. High-density dislocations produced in plastic flow do not disappear even if the flow is stopped. Thus large applied strains give rise to metastable, structurally disordered states. We divide the elastic energy into an elastic part due to affine deformation and a defect part. The latter represents degree of disorder and is nearly constant in plastic flow under cyclic straining.Comment: 16pages, Figures can be obtained at http://stat.scphys.kyoto-u.ac.jp/index-e.htm

Multi-spectral image processing for the measurement of a spatial temperature distribution on the surface of a laser-heated microscopic object

In this paper, we demonstrate that combining a laser heating (LH) system with a tandem acousto-optical tunable filter (TAOTF) allows us to measure the temperature distribution (TD) across a laser-heated microscopic specimen. Spectral image processing is based on one-dimensional (1D) non-linear least squares fitting of the Planck radiation function. It is applied for determining the temperature T at each point (x, y) of the specimen surface. It is shown that spectral image processing using the 1D non-linear least squares fitting allows measurement of the TD of the laser-heated microscopic specimen with higher precision and stability than those of the conventional linear least-squares fitting of the Wien approximation of Planck’s law.The Russian Science Foundation (project #17-12-01535) financially supported the work

Towards monitored tomographic reconstruction: algorithm-dependence and convergence

The monitored tomographic reconstruction (MTR) with optimized photon flux technique is a pioneering method for X-ray computed tomography (XCT) that reduces the time for data acquisition and the radiation dose. The capturing of the projections in the MTR technique is guided by a scanning protocol built on similar experiments to reach the predetermined quality of the reconstruction. This method allows achieving a similar average reconstruction quality as in ordinary tomography while using lower mean numbers of projections. In this paper, we, for the first time, systematically study the MTR technique under several conditions: reconstruction algorithm (FBP, SIRT, SIRT-TV, and others), type of tomography setup (micro-XCT and nano-XCT), and objects with different morphology. It was shown that a mean dose reduction for reconstruction with a given quality only slightlyvaries with choice of reconstruction algorithm, and reach up to 12.5 % in case of micro-XCT and 8.5 % for nano-XCT. The obtained results allow to conclude that the monitored tomographic reconstruction approach can be universally combined with an algorithm of choice to perform a controlled trade-off between radiation dose and image quality. Validation of the protocol on independent common ground truth demonstrated a good convergence of all reconstruction algorithms within the MTR protocol.This work was partly supported by RFBR (grants) 20-07-00934

Similarity and Differences of the Economic Crisis in the United States and Russia

The article analyzes the causes of the crisis in the United States and Russia and their anticrisis policies. The author notes that, despite similarities in the two countries' efforts to actively support their banks, major differences exist between their respective anticrisis policies in other areas. The U.S. administration is especially supportive of consumer demand, which accounts for the largest part of demand in the United States. In Russia, by contrast, the authorities provide support first and foremost to large-scale business and to the lower economic strata of society. In essence, the author concludes, we are dealing with two behavioral types of different national socioeconomic modelsâliberal capitalism in the United States and state capitalism in Russia.

Aleksey peshkov as an editor of samarskaya gazeta

© 2020, A. S. Bik-Bulatov The article uses little known letters of M. Gorky, many of which were published for the first time in 1997, as well as findings of Samara-based experts in local history to shed light on the writer’s work as editor-in-chief of the Samarskaya Gazeta newspaper in 1895. The researcher introduces hitherto unstudied reminiscences of the journalist D. Linyov (Dalin) about this period, which reference a letter by Gorky, now lost. The paper details a newly discovered episode of Gorky’s professional biography as a journalist: it concerns his campaign against a Samara ‘she-wolf,’ the madam of a local brothel A. Neucheva. Linyov’s reminiscences turn out to be an important and interesting source, offering an insight into the daily grind of the young editor Gorky, providing new evidence of his excellent organizational skills, and describing his moral and social stance. The author presents his work in the context of a recently initiated broader discussion about the need to map out all Russian periodicals for the period until 1917, as well as all research devoted to individual publications

Low-temperature elastic properties of Zr₅₅Al₁₀Ni₅Cu₃₀ bulk metallic glass doped with yttrium

The temperature dependence of elastic constants cij(T) of zirconium Zr₅₅Al₁₀Ni₅Cu₃₀-based, 1 % yttrium-doped bulk metallic glass (BMG) within the temperature range of 78 to 300 K was examined using the method of resonance spectroscopy. The measurements helped determine low-temperature behavior of elastic Young's modulus (E), shear modulus (G) and bulk modulus. BMG doping with yttrium allowed to obtain high value of the Poisson's ratio (σ) and the B/G ratio and note weak dependence of B(T) stemming from the appearance of an efficient dense pack of atomic clusters with icosahedral ordering symmetry within their internal structure. It was discovered that under 300 K, 1 % of yttrium reduces E by 5.4 % in comparison with the size of original BMG matrix. Analysis of the Debye temperature (θD) pattern points out the predominant contribution of phonon anharmonicity to BMG's elastic properties. It was assumed that high value of the Gruneisen parameter (γ) is due to manifestation of particularities of oscillatory properties

Granulocyte-macrophage colony-stimulating factor and car-t technology for solid tumors in experiment

© 2020 Practical Medicine Publishing House. All rights reserved. Background. Cytokines are considered as important factors that enhance the efficacy of CAR-T cell therapy. Besides, they are key elements of the pathogenesis of cytokine release syndrome and neurotoxicity in applying the CAR-T technology. However, cytokine effects in the context of CAR-T therapy have not yet been properly studied. Aim. To quantitatively assess cytokine secretion using multiplex assay with co-incubation of anti-CD19 CAR-T lymphocytes with epithelial HeLa and A431 cell lines expressing CD19 on their surface. Materials & Methods. T-lymphocytes were transduced with the lentiviral vector containing anti-СD19-CAR gene. CAR expression was tested based on GFP reporter using flow cytometry. To confirm a specific CAR-T cell activation response to tumor antigen, the levels of interleukin-2, interferon-γ, and tumor necrosis factor-α were measured by means of immunoassay. Cytotoxic activity of CAR-T lymphocytes obtained was examined with their direct co-culturing with target cells. The levels of cytokines isolated prior to and after incubation of targets with CAR-T cells were compared using multiplex assay. Results. The level of some proinflammatory cytokines (interleukin-6, interleukin-1β, interferon-γ) (p 0.05). The concentration of granulocyte-macrophage colony-stimulating factor (GM-CSF) was many times higher after incubation with CAR-T lymphocytes (p < 0.01). Conclusion. The trial revealed multiple enhancement of GM-CSF, one of the key elements of the pathogenesis of cytokine release syndrome and CAR-T-associated neurotoxicity. The results of further studies of GM-CSF can contribute to improving the efficacy of CAR-T therapy with considerably lower toxicity