Ideal two-dimensional electron systems with a giant Rashba-type spin splitting in real materials: surfaces of bismuth tellurohalides

Spintronics is aimed at active controlling and manipulating the spin degrees of freedom in semiconductor devices. A promising way to achieve this goal is to make use of the tunable Rashba effect that relies on the spin-orbit interaction (SOI) in a two-dimensional (2D) electron system immersed in an inversion-asymmetric environment. The SOI induced spin-splitting of the 2D-electron state provides a basis for many theoretically proposed spintronic devices. However, the lack of semiconductors with large Rashba effect hinders realization of these devices in actual practice. Here we report on a giant Rashba-type spin splitting in 2D electron systems which reside at tellurium-terminated surfaces of bismuth tellurohalides. Among these semiconductors, BiTeCl stands out for its isotropic metallic surface-state band with the Gamma-point energy lying deep inside the bulk band gap. The giant spin-splitting of this band ensures a substantial spin asymmetry of the inelastic mean free path of quasiparticles with different spin orientations.Comment: 12 pages, 5 figure

Methods of studying the composition of the low-energy ion beams and the surface of deuterated-metal targets

To study the reactions between the light nuclei (dd, pd, d{3}He, d{4}He) with ultralow collision energies, there is a need to obtain the high-precision experimental results on the purity of the target surface saturated with the hydrogen isotopes (protium, deuterium) and on the number and composition of the accelerated particles falling on the target. To solve this problem, a method has been developed and tested for operational testing the quality of the vacuum system and the cleaning of the metal target surface saturated with deuterium. The paper also presents the measurement results for the true flow of the accelerated ions and neutrals of hydrogen (deuterium), using a multigrid electrostatic energy analyzer. The values of the ion and neutral components of the accelerated particle flow were received for the Hall ion source. The values of the secondary electron emission coefficients were determined for a number of the metal targets (Cu, Ti, Ta, Zr) in the range of the accelerated ion energies of 3-12 keV

Non-autoregressive real-time Accent Conversion model with voice cloning

Currently, the development of Foreign Accent Conversion (FAC) models utilizes deep neural network architectures, as well as ensembles of neural networks for speech recognition and speech generation. The use of these models is limited by architectural features, which does not allow flexible changes in the timbre of the generated speech and requires the accumulation of context, leading to increased delays in generation and makes these systems unsuitable for use in real-time multi-user communication scenarios. We have developed the non-autoregressive model for real-time accent conversion with voice cloning. The model generates native-sounding L1 speech with minimal latency based on input L2 accented speech. The model consists of interconnected modules for extracting accent, gender, and speaker embeddings, converting speech, generating spectrograms, and decoding the resulting spectrogram into an audio signal. The model has the ability to save, clone and change the timbre, gender and accent of the speaker's voice in real time. The results of the objective assessment show that the model improves speech quality, leading to enhanced recognition performance in existing ASR systems. The results of subjective tests show that the proposed accent and gender encoder improves the generation quality. The developed model demonstrates high-quality low-latency accent conversion, voice cloning, and speech enhancement capabilities, making it suitable for real-time multi-user communication scenarios.Comment: 8 pages, 6 figures, 3 table

New generation of two-dimensional spintronic systems realized by coupling of Rashba and Dirac fermions

Intriguing phenomena and novel physics predicted for two-dimensional (2D) systems formed by electrons in Dirac or Rashba states motivate an active search for new materials or combinations of the already revealed ones. Being very promising ingredients in themselves, interplaying Dirac and Rashba systems can provide a base for next generation of spintronics devices, to a considerabl

Development and analysis of an algorithm for detecting multiple instances of an object in microscopic images using numerical methods

This paper presents a method for object detection in microscopy images, focusing on particle detection. The main objective of the research is to develop an algorithm capable of efficiently detecting multiple instances of objects in various scenarios, while maintaining specificity for structures of interest. The algorithm is based on using extremal regions as candidates for detection, followed by evaluating these regions with trained parameters. A key element of the algorithm is its built-in non-overlapping constraint, which enables effective handling of particle clustering. Experimental results on various microscopy datasets confirm the method's robustness to changes in image intensity, particle density, and size. The proposed algorithm serves as a valuable tool in the development of object detection methods for microscopy images and can be applied in both scientific and medical research

Non-Enzymatic Template-Directed Recombination of RNAs

RNA non-enzymatic recombination reactions are of great interest within the hypothesis of the “RNA world”, which argues that at some stage of prebiotic life development proteins were not yet engaged in biochemical reactions and RNA carried out both the information storage task and the full range of catalytic roles necessary in primitive self-replicating systems. Here we report on the study of recombination reaction occuring between two 96 nucleotides (nts) fragments of RNAs under physiological conditions and governed by a short oligodeoxyribonucleotide template, partially complementary to sequences within each of the RNAs. Analysis of recombination products shows that ligation is predominantly template-directed, and occurs within the complementary complex with the template in “butt-to-butt” manner, in 1- or 3- nts bulges or in 2–3 nts internal loops. Minor recombination products formed in the template-independent manner are detected as well

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

STATISTICS OF NODES AND RANDOM WALKS WITH TOPOLOGICAL LIMITATIONS

The probabilistic-topological properties of the random nodes have been studied. The basic attention has been paid to the problems on the determination of the node entropy and their connections with problems of the non-ordered system theory. The properties of the limit distributions for random walks on some non-commutative groups have been investigated. The physical properties of the polymer systems with topological limitations have been considered.Available from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio