Effect of dimephosphon on functional recovery of damaged spinal cord

The effect of endolumbar dimephosphon perfusion in dogs with spinal cord contusion was studied by means of transcranial magnetic stimulation and stimulation electromyography. Treatment with dimephosphon contributed to preservation of conduction function of the spinal cord and decrease in excitability of spinal motoneurons in the perifocal zone. © Springer Science+Business Media, Inc. 2006

Possible specialization of motoneuron axonal compartments in synthesis of particular proteins

Spontaneous quantal neurotransmitter release and its modulation was studied on neuromuscular preparations of rat soleus from intact animals and from animals in which colchicine had been applied to the sciatic nerve to block the axonal transport. After six days of colchicine application, neither the spontaneous quantal secretion nor its reaction to potassium-induced membrane depolarization or to activation of the presynaptic acetylcholine receptors with carbachol were disturbed in any way. Keeping in mind the relatively short half-life of proteins that take part in exocytosis and its regulation, it may be concluded that the functioning of the terminal neurosecretory apparatus does not depend on the state of axonal transport. These data are consistent with the earlier hypothesis that some proteins performing their functions in nerve terminals are synthesized directly at the site of their operation, rather than in the perikaryon as traditionally assumed. © 2010 Pleiades Publishing, Ltd

Mechanisms of spinal motoneurons survival in rats under simulated hypogravity on earth

It was previously shown that different cell types in vivo and in vitro may die via apoptosis under weightlessness conditions in space as well as in simulated hypogravity on the Earth. We assessed survivability of spinal motoneurons of rats after 35-day antiorthostatic hind limb suspension. Following weight bearing, unloading the total protein content in lumbar spinal cord is dropped by 21%. The electrophysiological studies of m. gastrocnemius revealed an elevated motoneurons' reflex excitability and conduction disturbances in the sciatic nerve axons. The number of myelinated fibers in the ventral root of experimental animals was insignificantly increased by 35-day of antiorthostatic hind limb suspension, although the retrograde axonal transport was significantly decreased during the first week of simulated hypogravity. The results of the immunohistochemical assay with antibodies against proapoptotic protein caspase 9 and cytotoxicity marker neuron specific nitric oxide synthase (nNOS) and the TUNEL staining did not reveal any signs of apoptosis in motoneurons of suspended and control animals. To examine the possible adaptation mechanisms activated in motoneurons in response to simulated hypogravity we investigated immunoexpression of Hsp25 and Hsp70 in lumbar spinal cord of the rats after 35-day antiorthostatic hind limb suspension. Comparative analysis of the immunohistochemical reaction with anti-Hsp25 antibodies revealed differential staining of motoneurons in intact and experimental animals. The density of immunoprecipitate with anti-Hsp25 antibodies was substantially higher in motoneurons of the 35-day suspended than control rats and the more intensive precipitate in this reaction was observed in motoneuron neuritis. Quantitative analysis of Hsp25 expression demonstrated an increase in the Hsp25 level by 95% in experimental rats compared to the control. The immunoexpression of Hsp70 found no qualitative and quantitative differences in control and experimental lumbar spinal cords. Taken together our results show that (1) rat motoneurons survived after 35-day antiorthostatic hind limb suspension and the changes in neurons had a mostly functional character, and (2) the increased immunoexpression of Hsp25 can be considered as the anti-apoptotic factor. © 2009 Elsevier Ltd. All rights reserved

Individual RF Test Results of the Cavities Used in the First US-built ILC-type Cryomodule

Eight 1.3-GHz, nine-cell SRF cavities have been installed in a cryomodule intended to demonstrate the ILC design goal of 31.5 MV/m. These cavities all underwent two types of individual RF testing: a low-power continuous-wave test of the 'bare' cavity and a high-power pulsed test of the 'dressed' cavity. Presented here is a discussion of the results from these tests and a comparison of their performance in the two configurations

Electronic band structure of three-dimensional topological insulators with different stoichiometry composition

We report on a comparative theoretical and experimental investigation of the electronic band structure of a family of three-dimensional topological insulators, AIVBi4Te7−xSex (AIV= Sn, Pb;x = 0, 1). We prove by means of density functional theory calculations and angle-resolved photoemission spectroscopy measurements that partial or total substitution of heavy atoms by lighter isoelectronic ones affects the electronic properties of topological insulators. In particular, we show that the modification of the Dirac cone position relative to the Fermi level and the bulk band gap size can be controlled by varying the stoichiometry of the compound. We also demonstrate that the investigated systems are inert to oxygen exposure.The authors acknowledge financial support from the Saint Petersburg State University (Grant No. 40990069), the Tomsk State University competitiveness improvement program (Grant No. 8.1.01.2018), the Fundamental Research Program of the State Academies of Sciences (line of research III.23.2.9), and the project EUROFEL-ROADMAP ESFRI. This work was also partly supported by the Italian Ministry of Education, Universities and Research (MIUR) through project PON03PE_00092_1 (EOMAT) and by the Science Development Foundation under the President of the Republic of Azerbaijan (Grant No. EIF/MQM/Elm-Tehsil-1-2016- 1(26)-71/01/4-M-33). S.V.E. acknowledges support from the Russian Science Foundation (Grant No. 18-12-00169) for part of the electronic band structure calculations.Peer reviewe

Ferromagnetic HfO2/Si/GaAs interface for spin-polarimetry applications

In this letter, we present electrical and magnetic characteristics of HfO2-based metal-oxide-semiconductor capacitors (MOSCAPs), along with the effect of pseudomorphic Si as a passivating interlayer on GaAs(001) grown by molecular beam epitaxy. Ultrathin HfO2 high-k gate dielectric films (3–15 nm) have been grown on Si/GaAs(001) structures through evaporation of a Hf/HfO2 target in NO2 gas. The lowest interface states density Dit at Au/HfO2/Si/GaAs(001) MOS-structures were obtained in the range of (6−13)×101

An observation of the f0(1710)f_0(1710) meson in the ωϕ\omega\phi system in the Pion-BeBe Interaction at Momentum of 29 GeV

The charge-exchange reaction $\pi^-p \rightarrow n\,\omega(783)\phi(1020)$, $\omega \rightarrow \pi^+\pi^-\pi^0$, $\phi \rightarrow K^+K^-$ is studied with the upgraded VES facility (U-70, Protvino) in the interaction of a 29 GeV pion beam with a beryllium target. The distribution over the invariant mass of the system $M_{\omega\phi}$ shows a near-threshold signal. A partial wave analysis reveals that the scalar state ($J^{PC}=0^{++}$) dominates in this mass region. The observed signal can be described with a contribution of the known resonance $f_0(1710)$. Using OPE approximation for the reaction $\pi^-p \rightarrow n\, f_0(1710)$ the product of branching fractions is found to be: $Br(f_0(1710)\rightarrow \pi\pi)\cdot Br(f_0(1710)\rightarrow \omega\phi) = (4.8 \pm 1.2) \cdot 10^{-3}$

Nature of the Dirac gap modulation and surface magnetic interaction in axion antiferromagnetic topological insulator MnBi2Te4A

Modification of the gap at the Dirac point (DP) in axion antiferromagnetic topological insulator MnBi2Te4 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 Neel 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.The authors acknowledge support by the Saint Petersburg State University (Grant No. 51126254), Russian Science Foundation (Grant No. 18-12-00062 in part of the photoemission measurements and Grant No. 18-12-00169 in part of the electronic band structure calculations) and by Russian Foundation of Basic Researches (Grants Nos. 18-52-06009 and 20-32-70179) and Science Development Foundation under the President of the Republic of Azerbaijan (Grant No. EI F-BGM-4-RFTF1/2017-21/04/1-M-02). A. Kimura was financially supported by KAKENHI (Grants No. 17H06138, No. 17H06152, and No. 18H03683). S.V.E. and E.V.C. acknowledge support by the Fundamental Research Program of the State Academies of Sciences (line of research III.23.2.9). The authors kindly acknowledge the HiSOR staff and A. Harasawa at ISSP for technical support and help with the experiment. The ARPES measurements at HiSOR were performed with the approval of the Proposal Assessing Committee (Proposal Numbers: 18BG027 and 19AG048). XAS and XMCD measurements were performed at BL23SU of SPring-8 (Proposal Nos. 2018A3842 and 2018B3842) under the Shared Use Program of JAEA Facilities (Proposal Nos. 2018A-E25 and 2018B-E24) with the approval of Nanotechnology Platform project supported by MEXT, Japan (Proposal Nos. A-18-AE-0020 and A-18-AE-0042). M. M. Otrokov acknowledges the support by Spanish Ministerio de Ciencia e Innovacion (Grant no. PID2019-103910GB-I00). K. Yaji was financially supported by KAKENHI (Grants No. 18K03484)

Nature of the Dirac gap modulation and surface magnetic interaction in axion antiferromagnetic topological insulator MnBi2_2Te4_4

Modification of the gap at the Dirac point (DP) in antiferromagnetic (AFM) axion topological insulator MnBi$_2$Te$_4$ and its electronic and spin structure has been studied by angle- and spin-resolved photoemission spectroscopy (ARPES) under laser excitation with variation of temperature (9-35~K), light polarization and photon energy. We have distinguished both a large (62-67~meV) and a reduced (15-18~meV) gap at the DP in the ARPES dispersions, which remains open above the N\'eel temperature ($T_\mathrm{N}=24.5$~K). We propose that the gap above $T_\mathrm{N}$ remains open due to short-range magnetic field generated by chiral spin fluctuations. Spin-resolved ARPES, XMCD and circular dichroism ARPES measurements show a surface ferromagnetic ordering for large-gap sample and significantly reduced effective magnetic moment for the reduced-gap sample. These effects can be associated with a shift of the topological DC state towards the second Mn layer due to structural defects and mechanical disturbance, where it is influenced by a compensated effect of opposite magnetic moments