Тhe role of bafilomycin as a therapeutic agent in the modulation of endo-lysosomal store of rat hepatocytes

Endo-lysosomal system through the process of autophagy is involved in the pathogenesis of many diseases. Acidification of these organelles is carried out by V-type H+-ATPases, which is inhibited by bafilomycin A1. Endosomes and lysosomes are also important Ca2+-storage in a cell. Nіcotіnіc acіd adenіne dіnucleotіde phosphate (NAADP) releases Cа2+ from endo-lysosomes. The main purpose of the study was to found out the effect of bafilomycin A1 and NAADP on stored Ca2+ and on the ATPase activity of rat hepatocytes. The stored Ca2+ was estimated using chlorotetracycline in permeabilized hepatocytes of rats. ATPase activity was determined by level of orthophosphate spectrophotometrically. It was found that bafilomycin A1 reduces stored Ca2+ in permeabilized hepatocytes of rats in the micromolar range of concentration (20 and 0.04 mkM) and averted the effect of NAADP on calcium content. Lower concentrations of bafilomycin A1 (0.001 mkM) did not alter the content of stored calcium, but prevented the influence of NAADP in permeabilized hepatocytes of rats. In the subcellular fraction of rat liver bafilomycin A1 (0.001 mkM) increased Ca2+-ATPase and basal Mg2+-ATPase activities and reduced Na+/K+-ATPase activity. Preincubation of the subcellular fraction with bafilomycin A1 completely averts any changes in the activity of estimated ATPases by means of NAADP. It was concluded that the bafilomycin-sensitive store in hepatocytes of rats is NAADP-sensitive endo-lysosomal Ca2+-store. Using of bafilomycin A1 may be useful in treating autophagy-depended disease

The technology of creating a virtual museum on the example of a «Virtual museum studio of works by students of the Irkutsk art college»

The article is a socio-cultural project to create a virtual museum studio, the subject of which is the works of students of the Irkutsk Regional Art College named after I. L. Kopylov. The purpose of this work is to demonstrate a way to create a virtual museum through demonstration software. In this project, methods of 3D modeling and creation of panoramic tours are used, since the proposed museum of student works does not have a real space and exists only in virtual reality. The creation of the project was based on such normative documents as: Order of the Ministry of Culture of the Russian Federation No. 827 dated July 23, 2020 "On approval of Uniform rules for the organization of acquisition, accounting, storage and use of museum objects and museum collections", as well as "Technical recommendations of the Ministry of Culture of the Russian Federation on the creation of virtual museums". The process of creating the project consisted of several stages: definition of the term "virtual museum", selection of software, development and design of a 3D model, interior and exterior design of a museum building, selection and digitization of students' artwork, creation of panoramic images, collection of a panoramic tour, development of a tour management interface, creation of a label and audio guide. The result is a virtual museum studio project, which, firstly, demonstrates the creativity of young artists in an interesting way; secondly, it allows you to preserve artistic works forever; thirdly, it demonstrates how the problem of the absence of an exhibition space can be solved with the help of virtual reality. Such virtual museums can be used for educational purposes and for tourist services.Работа представляет собой социокультурный проект по созданию виртуальной музейной студии, предметом экспонирования которой являются работы учащихся Иркутского областного художественного колледжа им. И. Л. Копылова. Цель данной работы заключается в демонстрации способа создания виртуального музея посредством демонстрационного программного обеспечения. Принципы, использующиеся в создании данного проекта, задействуют технологии 3D-моделирования и создания панорамных туров, так как предполагаемый музей работ учащихся не имеет реального пространства и существует лишь в виртуальной реальности. Создание проекта шло с опорой на такие нормативно-правовые документы, как Приказ Министерства культуры РФ от 23 июля 2020 г. № 827 «Об утверждении Единых правил организации комплектования, учета, хранения и использования музейных предметов и музейных коллекций», «Технические рекомендации Министерства культуры РФ по созданию виртуальных музеев». Процесс создания проекта состоял из нескольких этапов: определение термина «виртуальный музей», подбор программного обеспечения, разработка и проектирование 3D-модели, дизайн интерьера и экстерьера музейного здания, отбор и оцифровка художественных работ учащихся, создание панорамных изображений, сбор панорамного тура, разработка интерфейса управления туром, создание этикетажа и аудиогида. В результате проведения этих работ получился проект виртуальной музейной студии, который способен, во-первых, интересно преподнести творчество юных художников; во-вторых, обеспечить сохранность художественных работ; в-третьих, продемонстрировать на практике решение проблемы отсутствия выставочного помещения с помощью виртуальной реальности. Подобного рода виртуальные музеи могут служить как в образовательных целях, так и в целях туристского обслуживания

Persistent spin splitting of a two-dimensional electron gas in tilted magnetic fields

By varying the orientation of the applied magnetic field with respect to the normal of a two-dimensional electron gas, the chemical potential and the specific heat reveal persistent spin splitting in all field ranges. The corresponding shape of the thermodynamic quantities distinguishes whether the Rashba spin-orbit interaction RSOI, the Zeeman term or both dominate the splitting. The interplay of the tilting of the magnetic field and RSOI resulted to an amplified splitting in weak fields. The effects of changing the RSOI strength and the Landau level broadening are also investigated.Comment: 10 pages, 5 figure

Radiation-induced oscillatory magnetoresistance as a sensitive probe of the zero-field spin splitting in high mobility GaAs/AlGaAs devices

We suggest an approach for characterizing the zero-field spin splitting of high mobility two-dimensional electron systems, when beats are not readily observable in the Shubnikov-de Haas effect. The zero-field spin splitting and the effective magnetic field seen in the reference frame of the electron is evaluated from a quantitative study of beats observed in radiation-induced magnetoresistance oscillations.Comment: 4 pages, 4 color figure

Nab: Measurement Principles, Apparatus and Uncertainties

The Nab collaboration will perform a precise measurement of 'a', the electron-neutrino correlation parameter, and 'b', the Fierz interference term in neutron beta decay, in the Fundamental Neutron Physics Beamline at the SNS, using a novel electric/magnetic field spectrometer and detector design. The experiment is aiming at the 10^{-3} accuracy level in (Delta a)/a, and will provide an independent measurement of lambda = G_A/G_V, the ratio of axial-vector to vector coupling constants of the nucleon. Nab also plans to perform the first ever measurement of 'b' in neutron decay, which will provide an independent limit on the tensor weak coupling.Comment: 12 pages, 6 figures, 1 table, talk presented at the International Workshop on Particle Physics with Slow Neutrons, Grenoble, 29-31 May 2008; to appear in Nucl. Instrum. Meth. in Physics Research

Rashba spin–orbit coupling effect on the quantum Hall magnetoresistivity

In this paper we analyze the influence of the Rashba spin–orbit coupling on the quantum Hall magnetoresistivity in a two-dimensional electron system (2DES). The study is based on an analytical model for the integer quantum Hall effect (IQHE) and the Shubnikov-de Haas (SdH) phenomena. This model shows the behaviour of the Hall magnetoresistivity when the Rashba parameter is varied, and reproduces Hall plateaux of a 2DES confined in a III–V heterostructure. We also discuss the Rashba and Zeeman competition and its effect on the width of the Hall magnetoresistivity plateaux

Spin dynamics in high-mobility two-dimensional electron systems

Understanding the spin dynamics in semiconductor heterostructures is highly important for future semiconductor spintronic devices. In high-mobility two-dimensional electron systems (2DES), the spin lifetime strongly depends on the initial degree of spin polarization due to the electron-electron interaction. The Hartree-Fock (HF) term of the Coulomb interaction acts like an effective out-of-plane magnetic field and thus reduces the spin-flip rate. By time-resolved Faraday rotation (TRFR) techniques, we demonstrate that the spin lifetime is increased by an order of magnitude as the initial spin polarization degree is raised from the low-polarization limit to several percent. We perform control experiments to decouple the excitation density in the sample from the spin polarization degree and investigate the interplay of the internal HF field and an external perpendicular magnetic field. The lifetime of spins oriented in the plane of a [001]-grown 2DES is strongly anisotropic if the Rashba and Dresselhaus spin-orbit fields are of the same order of magnitude. This anisotropy, which stems from the interference of the Rashba and the Dresselhaus spin-orbit fields, is highly density-dependent: as the electron density is increased, the kubic Dresselhaus term becomes dominant and reduces the anisotropy.Comment: 13 pages, 6 figure

Magnetothemopower study of quasi two-dimensional organic conductor α\alpha-(BEDT-TTF)2_2KHg(SCN)4_4

We have used a low-frequency magneto-thermopower (MTEP) method to probe the high magnetic field ground state behavior of $\alpha$-(BEDT-TTF)$_2$KHg(SCN)$_4$ along all three principal crystallographic axes at low temperatures. The thermopower tensor coefficients ($S_{xx}, S_{yx}$ and $S_{zz}$) have been measured to 30 T, beyond the anomalous low temperature, field-induced transition at 22.5 T. We find a significant anisotropy in the MTEP signal, and also observe large quantum oscillations associated with the de Haas - van Alphen effect. The anisotropy indicates that the ground state properties are clearly driven by mechanisms that occur along specific directions for the in-plane electronic structure. Both transverse and longitudinal magnetothermopower show asymptotic behavior in field, which can be explained in terms of magnetic breakdown of compensated closed orbits.Comment: 9 pages, 10 figure

Spin oscillations in transient diffusion of a spin pulse in n-type semiconductor quantum wells

By studying the time and spatial evolution of a pulse of the spin polarization in $n$-type semiconductor quantum wells, we highlight the importance of the off-diagonal spin coherence in spin diffusion and transport. Spin oscillations and spin polarization reverse along the the direction of spin diffusion in the absence of the applied magnetic field are predicted from our investigation.Comment: 5 pages, 4 figures, accepted for publication in PR

Spin-current modulation and square-wave transmission through periodically stubbed electron waveguides

Ballistic spin transport through waveguides, with symmetric or asymmetric double stubs attached to them periodically, is studied systematically in the presence of a weak spin-orbit coupling that makes the electrons precess. By an appropriate choice of the waveguide length and of the stub parameters injected spin-polarized electrons can be blocked completely and the transmission shows a periodic and nearly square-type behavior, with values 1 and 0, with wide gaps when only one mode is allowed to propagate in the waveguide. A similar behavior is possible for a certain range of the stub parameters even when two-modes can propagate in the waveguide and the conductance is doubled. Such a structure is a good candidate for establishing a realistic spin transistor. A further modulation of the spin current can be achieved by inserting defects in a finite-number stub superlattice. Finite-temperature effects on the spin conductance are also considered.Comment: 19 pages, 8 figure