Coulomb Correlations and Magnetic Anisotropy in ordered L10L1_0 CoPt and FePt alloys

We present results of the magneto-crystalline anisotropy energy (MAE) calculations for chemically ordered $L1_0$ CoPt and FePt alloys taking into account the effects of strong electronic correlations and spin-orbit coupling. The local spin density + Hubbard U approximation (LSDA+U) is shown to provide a consistent picture of the magnetic ground state properties when intra-atomic Coulomb correlations are included for both 3$d$ and 5$d$ elements. Our results demonstrate significant and complex contribution of correlation effects to large MAE of these material.Comment: revised version; 4 pages, 2 figure

Specific features of the electronic, spin, and atomic structures of a topological insulator Bi2Te2.4Se0.6

The specific features of the electronic and spin structures of a triple topological insulator Bi2Te2.4Se0.6, which is characterized by high-efficiency thermoelectric properties, have been studied with the use of angular- and spin-resolved photoelectron spectroscopy and compared with theoretical calculations in the framework of the density functional theory. It has been shown that the Fermi level for Bi2Te2.4Se0.6 falls outside the band gap and traverses the topological surface state (the Dirac cone). Theoretical calculations of the electronic structure of the surface have demonstrated that the character of distribution of Se atoms on the Te–Se sublattice practically does not influence the dispersion of the surface topological electronic state. The spin structure of this state is characterized by helical spin polarization. Analysis of the Bi2Te2.4Se0.6 surface by scanning tunnel microscopy has revealed atomic smoothness of the surface of a sample cleaved in an ultrahigh vacuum, with a lattice constant of ~4.23 Å. Stability of the Dirac cone of the Bi2Te2.4Se0.6 compound to deposition of a Pt monolayer on the surface is shown.This study was supported by the Ministry of Education and Science of the Russian Federation, the St. Petersburg State University (project nos. 11.38.271.2014 and 15.61.202.2015), and the Russian Foundation for Basic Research (project nos. 12-02-00226, 13-02-91327, 14-08-31110, and 13-02-12110). The research was also performed at the Resource Center “Physical Methods of Surface Investigation” at St. Petersburg State University. We are also grateful to collaborators of the Helmholtz-Zentrum (Berlin) for financial and technical support.Peer reviewe

Site- and spin-dependent coupling at the highly ordered h-BN/Co(0001) interface

Using photoelectron diffraction and spectroscopy, we explore the structural and electronic properties of the hexagonal boron nitride (h-BN) monolayer epitaxially grown on the Co(0001) surface. Perfect matching of the lattice parameters allows formation of a well-defined interface where the B atoms occupy the hollow sites while the N atoms are located above the Co atoms. The corrugation of the h-BN monolayer and its distance from the substrate were determined by means of R-factor analysis. The obtained results are in perfect agreement with the density functional theory (DFT) predictions. The electronic structure of the interface is characterized by a significant mixing of the h-BN and Co states. Such hybridized states appear in the h-BN band gap. This allows to obtain atomically resolved scanning tunneling microscopy (STM) images from the formally insulating 2D material being in contact with ferromagnetic metal. The STM images reveal mainly the nitrogen sublattice due to a dominating contribution of nitrogen orbitals to the electronic states at the Fermi level. We believe that the high quality, well-defined structure and interesting electronic properties make the h-BN/Co(0001) interface suitable for spintronic applications.L.V.Ya. acknowledges the RSF (Grant No. 16-42-01093). A.V.T., V.O.S., K.A.B., O.Yu.V., and D.Yu.U. acknowledge St. Petersburg State University for research Grant No. 11.65.42.2017. M.V.K. and I.I.O. acknowledge the RFBR (Grant No. 16-29-06410). C.L. acknowledges the DFG (Grant Nos. LA655-17/1 and LA655-19/1).Peer reviewe

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

Two-particle correlations in azimuthal angle and pseudorapidity in inelastic p + p interactions at the CERN Super Proton Synchrotron

Results on two-particle ΔηΔϕ correlations in inelastic p + p interactions at 20, 31, 40, 80, and 158 GeV/c are presented. The measurements were performed using the large acceptance NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The data show structures which can be attributed mainly to effects of resonance decays, momentum conservation, and quantum statistics. The results are compared with the Epos and UrQMD models.ISSN:1434-6044ISSN:1434-605

Design of A Composition Based on Polyethylene and Marble Microparticles That Decomposes Under the Effect of Ultraviolet Radiation

Among the issues related to the disposal of polymers' waste is the design of cheap biodegradable polymeric materials, which are destroyed as a result of natural microbiological and chemical processes. Since the synthesis of biodegradable polymers is characterized by high material and energy costs, the filled biodegradable polymeric materials are more promising.This paper substantiates the feasibility of using marble microparticles as a filler for the biodegradable polymeric material based on high-pressure polyethylene whose decomposition rate increases under the conditions of ultraviolet radiation.Samples of the biodegradable polymeric material with the different content of a filler, the microparticles of marble (from 0 to 5.1 % by weight), were made; their physical-mechanical properties were investigated. It has been experimentally proven that UV radiation destroys polyethylene macromolecules into separate fragments with the formation of >C=O bonds, making it possible to decompose appropriate waste under the influence of sunlight.The feasibility of using the composition "high-pressure polyethylene – microparticles of marble" with a marble content of 1.78 % by weight has been confirmed for the manufacture of the sleeve and flat polymeric films for packaging and agricultural purposes, in particular, packing stretch film.Recommendations have been given on using the proposed biodegradable polymeric material. In particular, it is proposed that the production of articles from the "high-pressure polyethylene – microparticles of marble" composition should utilize a pre-obtained granulate of the required formulation. When making articles from the composition obtained directly in the extruder that molds the products, it is possible to apply adhesive additives to improve the interaction between a polymeric matrix and the filler's particle

Cryochemically Processed Li1+yMn1.95Ni0.025Co0.025O4 (y = 0, 0.1) Cathode Materials for Li-Ion Batteries

A new route for the preparation of nickel and cobalt substituted spinel cathode materials (LiMn1.95Co0.025Ni0.025O4 and Li1.1Mn1.95Co0.025Ni0.025O4) by freeze-drying of acetate precursors followed by heat treatment was suggested in the present work. The experimental conditions for the preparation single-phase material with small particle size were optimized. Single-phase spinel was formed by low-temperature annealing at 700 °C. For discharge rate 0.2 C, the reversible capacities 109 and 112 mAh g−1 were obtained for LiMn1.95Co0.025Ni0.025O4 and Li1.1Mn1.95Co0.025Ni0.025O4, respectively. A good cycle performance and capacity retention about 90% after 30 cycles at discharge rate 0.2–4 C were observed for the materials cycled from 3 to 4.6 V vs. Li/Li+. Under the same conditions pure LiMn2O4 cathode materials represent a reversible capacity 94 mAh g−1 and a capacity retention about 80%. Two independent experimental techniques (cyclic voltammetry at different scan rates and electrochemical impedance spectroscopy) were used in order to investigate the diffusion kinetics of lithium. This study shows that the partial substitution of Mn in LiMn2O4 with small amounts of Ni and Co allows the cyclability and the performance of LiMn2O4-based cathode materials to be improved

The biological basis and clinical symptoms of CAR-T therapy-associated toxicites

Abstract Currently, immunotherapy is attracting a lot of attention and may potentially become a leading approach in the treatment of cancer. One emerging therapeutic, the chimeric-antigen receptor T-cell adoptive immunotherapy (CAR-T) is showing remarkable efficacy in the treatment of several B-cell malignancies. The popularity of CAR-T has been founded on two CAR T-cell products recently approved by FDA (during 2017) in the treatment of relapsed/refractory B-cell acute lymphoblastic leukemia and B-cell lymphoma. However, their toxicities observed in clinical trials were extremely significant and in some cases even fatal with no approved algorithms for toxicity prediction being available to date. A deeper understanding of the biological basis of such complications is the key to prompt and comprehensive clinical management. Here we review the wide spectrum of effects associated with CAR T cell therapy with a major focus on the pathogenesis of cytokine release syndrome and neurotoxicity as the most common, potentially life-threatening effects of this treatment. We discuss the basis of clinical management and the existing models that predict the severity of toxicity, as well as the key factors that modulate this event. Finally, we will summarize the literature detailing universal allogenic CAR T-cells and their toxicity profile

Novel isatin-derived molecules activate p53 via interference with Mdm2 to promote apoptosis

International audienceThe p53 protein is a key tumor suppressor in mammals. In response to various forms of genotoxic stress p53 stimulates expression of genes whose products induce cell cycle arrest and/or apoptosis. An E3-ubiquitin ligase, Mdm2 (mouse-double-minute 2) and its human ortholog Hdm2, physically interact with the amino-terminus of p53 to mediate its ubiquitin-mediated degradation via the proteasome. Thus, pharmacological inhibition of the p53-Mdm2 interaction leads to overall stabilization of p53 and stimulation of its anti-tumorigenic activity. In this study we characterize the biological effects of a novel class of non-genotoxic isatin Schiff and Mannich base derivatives (ISMBDs) that stabilize p53 on the protein level. The likely mechanism behind their positive effect on p53 is mediated via the competitive interaction with Mdm2. Importantly, unlike Nutlin, these compounds selectively promoted p53-mediated cell death. These novel pharmacological activators of p53 can serve as valuable molecular tools for probing p53-positive tumors and set up the stage for development of new anti-cancer drugs