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The parameters of dimmings and their relation to coronal mass ejections (CMEs) are studied to determine the location of possible sources of ejections on the solar disk during solar cycle 24. We used the Solar Demon database, which contains information on flares and dimmings obtained by processing images from the SDO/AIA space observatory. Of all the analyzed dimmings, 16% are аssociated with CMEs from the CACTus database using SOHO/LASCO coronagraph data for 2010–2018. Based on the parameter distribution, it is found that dimmings related with CMEs are on average events with large absolute parameter values. The correlation coefficient between the position angle of the dimmings and the position angle of the CME associated with them is 0.96. For dimmings observed in the central part of the solar disk, we obtained correlation coefficients between the CME velocity and dimming parameters that are close to 0.5. The results can be used to model the propagation of CMEs and to refine the probability of their arrival to the near-Earth orbit.

The paper demonstrates results of modeling arrival time of coronal mass ejections (CME) to near-Earth space with parameters of coronal dimmings in 2010–2018. We use drag-based model (DBM) for CME propagation and empirical model for quasi-stationary solar wind streams. We compared the ICME arrival time and speed forecast for events with coronal source in the central region of the solar disk based on the CME initial speed using (1) CACTus database; (2) dimming maximum intensity drop from Solar Demon database to calculate the initial speed of the CME. Results show that the methods result in similar errors. To study the possibility of predicting ICME, for which a CME may not be observed in the coronagraph for some reason, modeling of ICME was carried out using dimming parameters. In 43% of cases, ICME arrival time were forecasted with an accuracy of 24 h using parameters of dimmings in the central region of solar disk that could not be associated with any CMEs.

The authors demonstrate the possibility of using CubeSat nanosatellites to study solar cosmic rays (SCRs). SCR electron fluxes over the polar caps at altitudes of ∼550 km are detected. Measurements are made using scintillation detectors of cosmic radiation (DeCoR) mounted on several CubeSat nanosatellites of Moscow State University during an SCR event on September 6–21, 2022.

TUS (Tracking Ultraviolet Set-up), the first orbital detector of extreme energy cosmic rays (EECRs), those with energies above 50 EeV, was launched into orbit on April 28, 2016, as a part of the Lomonosov satellite scientific payload. The main aim of the mission is to test a technique of registering fluorescent and Cherenkov radiation of extensive air showers generated by EECRs in the atmosphere with a space telescope. We present preliminary results of its operation in a mode dedicated to registering extensive air showers in the period from August 16, 2016, to November 4, 2016. No EECRs have been conclusively identified in the data yet, but the diversity of ultraviolet emission in the atmosphere was found to be unexpectedly rich. We discuss typical examples of data obtained with TUS and their possible origin. The data is important for obtaining more accurate estimates of the nocturnal ultraviolet glow of the atmosphere, necessary for successful development of more advanced orbital EECR detectors including those of the KLYPVE (K-EUSO) and JEM-EUSO missions.

TUS (Track Ultraviolet Setup) is the first space experiment aimed to check the possibility of registering extreme energy cosmic rays (EECRs) at E>50 EeV by measuring the fluorescence signal of extensive air showers in the atmosphere. The detector operates as a part of the scientific payload of the Lomonosov satellite for more than a year. We describe an algorithm of searching for EECR events in the TUS data and briefly discuss a number of candidates selected by formal criteria.

On April 28, 2016, the Lomonosov satellite, equipped with a number of scientific instruments, was launched into orbit. Here we present briefly some of the results obtained with the first orbital telescope of extreme energy cosmic rays TUS and by a group of detectors aimed at multi-messenger observations of gamma-ray bursts.

Materials that possess nontrivial topology and magnetism is known to exhibit exotic quantum phenomena such as the quantum anomalous Hall effect. Here, we fabricate a novel magnetic topological heterostructure Mn 4 Bi 2 Te 7 /Bi 2 Te 3 where multiple magnetic layers are inserted into the topmost quintuple layer of the original topological insulator Bi 2 Te 3 . A massive Dirac cone (DC) with a gap of 40–75 meV at 16 K is observed. By tracing the temperature evolution, this gap is shown to gradually decrease with increasing temperature and a blunt transition from a massive to a massless DC occurs around 200–250 K. Structural analysis shows that the samples also contain MnBi 2 Te 4 /Bi 2 Te 3 . Magnetic measurements show that there are two distinct Mn components in the system that corresponds to the two heterostructures; MnBi 2 Te 4 /Bi 2 Te 3 is paramagnetic at 6 K while Mn 4 Bi 2 Te 7 /Bi 2 Te 3 is ferromagnetic with a negative hysteresis (critical temperature  ~20 K). This novel heterostructure is potentially important for future device applications. Magnetic topological heterostructures are promising devices to manipulate emergent quantum effects. Here, Hirahara et al. fabricate a novel magnetic topological heterostructure with a massive Dirac cone which becomes a massless one tuned by temperature.

Modification of the gap at the Dirac point (DP) in axion antiferromagnetic topological insulator MnBi 2 Te 4 and its electronic and spin structure have been studied by angle- and spin-resolved photoemission spectroscopy (ARPES) under laser excitation at various temperatures (9–35 K), light polarizations and photon energies. We have distinguished both large (60–70 meV) and reduced ( < 20 meV ) gaps at the DP in the ARPES dispersions, which remain open above the Neél temperature ( T N = 24.5 K ). We propose that the gap above T N remains open due to a short-range magnetic field generated by chiral spin fluctuations. Spin-resolved ARPES, XMCD and circular dichroism ARPES measurements show a surface ferromagnetic ordering for the “large gap” sample and apparently significantly reduced effective magnetic moment for the “reduced gap” sample. These observations can be explained by a shift of the Dirac cone (DC) state localization towards the second Mn layer due to structural disturbance and surface relaxation effects, where DC state is influenced by compensated opposite magnetic moments. As we have shown by means of ab-initio calculations surface structural modification can result in a significant modulation of the DP gap.

Semiconductors with strong spin–orbit interaction as the underlying mechanism for the generation of spin-polarized electrons are showing potential for applications in spintronic devices. Unveiling the full spin texture in momentum space for such materials and its relation to the microscopic structure of the electronic wave functions is experimentally challenging and yet essential for exploiting spin–orbit effects for spin manipulation. Here we employ a state-of-the-art photoelectron momentum microscope with a multichannel spin filter to directly image the spin texture of the layered polar semiconductor BiTeI within the full two-dimensional momentum plane. Our experimental results, supported by relativistic ab initio calculations, demonstrate that the valence and conduction band electrons in BiTeI have spin textures of opposite chirality and of pronounced orbital dependence beyond the standard Rashba model, the latter giving rise to strong optical selection-rule effects on the photoelectron spin polarization. These observations open avenues for spin-texture manipulation by atomic-layer and charge carrier control in polar semiconductors. In semiconductors containing heavy elements, the Rashba spin-orbit interaction can couple the momentum and spin of electrons, yielding spintronic functionality. Here, the authors image band- and orbital-dependent spin-textures in the layered polar semiconductor BiTeI, demonstrating behaviour beyond the standard Rashba model.

Background Dozens of transplants generated from pluripotent stem cells are currently in clinical trials. The creation of patient-specific iPSCs makes personalized therapy possible due to their main advantage of immunotolerance. However, some reports have claimed recently that aberrant gene expression followed by proteome alterations and neoantigen formation can result in iPSCs recognition by autologous T-cells. Meanwhile, the possibility of NK-cell activation has not been previously considered. This study focused on the comparison of autologous and allogeneic immune response to iPSC-derived cells and isogeneic parental somatic cells used for reprogramming. Methods We established an isogeneic cell model consisting of parental dermal fibroblasts, fibroblast-like iPSC-derivatives (iPS-fibro) and iPS-fibro lacking beta-2-microglobulin (B2M). Using the cells obtained from two patients, we analyzed the activation of autologous and allogeneic T-lymphocytes and NK-cells co-cultured with target cells. Results Here we report that cells differentiated from iPSCs can be recognized by NK-cells rather than by autologous T-cells. We observed that iPS-fibro elicited a high level of NK-cell degranulation and cytotoxicity, while isogeneic parental skin fibroblasts used to obtain iPSCs barely triggered an NK-cell response. iPSC-derivatives with B2M knockout did not cause an additional increase in NK-cell activation, although they were devoid of HLA-I, the major inhibitory molecules for NK-cells. Transcriptome analysis revealed a significant imbalance of ligands for activating and inhibitory NK-cell receptors in iPS-fibro. Compared to parental fibroblasts, iPSC-derivatives had a reduced expression of HLA-I simultaneously with an increased gene expression of major activating ligands, such as MICA , NECTIN2 , and PVR . The lack of inhibitory signals might be due to insufficient maturity of cells differentiated from iPSCs. In addition, we showed that pretreatment of iPS-fibro with proinflammatory cytokine IFNγ restored the ligand imbalance, thereby reducing the degranulation and cytotoxicity of NK-cells. Conclusion In summary, we showed that iPSC-derived cells can be sensitive to the cytotoxic potential of autologous NK-cells regardless of HLA-I status. Thus, the balance of ligands for NK-cell receptors should be considered prior to iPSC-based cell therapies. Trial registration Not applicable.