462 research outputs found
A Rotating Collapsar and Possible Interpretation of the LSD Neutrino Signal from SN 1987A
We consider an improved rotational mechanism of the explosion of a collapsing
supernova. We show that this mechanism leads to two-stage collapse with a phase
difference of \sim 5 h. Based on this model, we attempt a new interpretation of
the events in underground neutrino detectors on February 23, 1987, related to
the supernova SN 1987A.Comment: 18 pages, 3 figures, 9 table
Magnetic and Superconducting Phase Diagram of Nb/Gd/Nb trilayers
We report on a study of the structural, magnetic and superconducting
properties of Nb(25nm)/Gd()/Nb(25nm) hybrid structures of a
superconductor/ ferromagnet (S/F) type. The structural characterization of the
samples, including careful determination of the layer thickness, was performed
using neutron and X-ray scattering with the aid of depth sensitive
mass-spectrometry. The magnetization of the samples was determined by SQUID
magnetometry and polarized neutron reflectometry and the presence of magnetic
ordering for all samples down to the thinnest Gd(0.8nm) layer was shown. The
analysis of the neutron spin asymmetry allowed us to prove the absence of
magnetically dead layers in junctions with Gd interlayer thickness larger than
one monolayer. The measured dependence of the superconducting transition
temperature has a damped oscillatory behavior with well defined
positions of the minimum at =3nm and the following maximum at =4nm;
the behavior, which is in qualitative agreement with the prior work (J.S. Jiang
et al, PRB 54, 6119). The analysis of the dependence based on Usadel
equations showed that the observed minimum at =3nm can be described by the
so called "" to "" phase transition of highly transparent S/F
interfaces with the superconducting correlation length nm in
Gd. This penetration length is several times higher than for strong
ferromagnets like Fe, Co or Ni, simplifying thus preparation of S/F structures
with which are of topical interest in superconducting
spintronics
Some New Reactions and Properties of Xanthane Hydride (5-Amino-1,2,4-dithiazole-3-thione)
Aminomethylation of xanthane hydride (5-amino-1,2,4-dithiazole-3-thione) with the RNH2–HCHO system has resulted in the formation of the derivatives of new heterocyclic system (3,7-dihydro-5H-[1,2,4]-dithiazolo[4,3-a][1,3,5]triazine) in low yields. The reaction of xanthane hydride with dicyandiamide has led to thioammeline [4,6-diamino-1,3,5-triazine-2(5Н)-thione]. Some practically important properties of xanthane hydride and its derivatives have been investigated. Xanthane hydride has efficiently exhibited carbon steel corrosion in neutral aqueous media. The prepared compounds have not exhibited growth-regulating or antidote activity to herbicide 2,4-D
Conservation laws of semidiscrete canonical Hamiltonian equations
There are many evolution partial differential equations which can be cast
into Hamiltonian form. Conservation laws of these equations are related to
one-parameter Hamiltonian symmetries admitted by the PDEs. The same result
holds for semidiscrete Hamiltonian equations. In this paper we consider
semidiscrete canonical Hamiltonian equations. Using symmetries, we find
conservation laws for the semidiscretized nonlinear wave equation and
Schrodinger equation.Comment: 19 pages, 2 table
Magnetic proximity effect in [Nb/Gd] superlattices seen by neutron scattering
We have used spin-polarized neutron reflectometry to investigate the
magnetization profile of superlattices composed of ferromagnetic Gd and
superconducting Nb layers. We have observed a partial suppression of
ferromagnetic (F) order of Gd layers in [Gd()/Nb(25nm)]
superlattices below the superconducting (S) transition of the Nb layers. The
amplitude of the suppression decreases with increasing . By analyzing the
neutron spin asymmetry we conclude that the observed effect has an
electromagnetic origin - the proximity-coupled S layers screen out the external
magnetic field and thus suppress the F response of the Gd layers inside the
structure. Our investigation demonstrates the considerable influence of
electromagnetic effects on the magnetic properties of S/F systems
Pyrrolylquinoxaline-2-one derivative as a potent therapeutic factor for brain trauma rehabilitation
Traumatic brain injury (TBI) often causes massive brain cell death accompanied by the accumulation of toxic factors in interstitial and cerebrospinal fluids. The persistence of the damaged brain area is not transient and may occur within days and weeks. Chaperone Hsp70 is known for its cytoprotective and antiapoptotic activity, and thus, a therapeutic approach based on chemically induced Hsp70 expression may become a promising approach to lower post-traumatic complications. To simulate the processes of secondary damage, we used an animal model of TBI and a cell model based on the cultivation of target cells in the presence of cerebrospinal fluid (CSF) from injured rats. Here we present a novel low molecular weight substance, PQ-29, which induces the synthesis of Hsp70 and empowers the resistance of rat C6 glioma cells to the cytotoxic effect of rat cerebrospinal fluid taken from rats subjected to TBI. In an animal model of TBI, PQ-29 elevated the Hsp70 level in brain cells and significantly slowed the process of the apoptosis in acceptor cells in response to cerebrospinal fluid action. The compound was also shown to rescue the motor function of traumatized rats, thus proving its potential application in rehabilitation therapy after TBI. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Ministry of Education and Science of the Russian Federation, Minobrnauka: 0124-2019-002Russian Foundation for Basic Research, RFBR: 20-33-70102Russian Science Foundation, RSF: 18-74-10087Funding: This research was funded by Russian Science Foundation, research project #18-74-10087 (V.F.L., E.A.D., M.A.M., E.R.M.), Russian Foundation for Basic Research, research project #20-33-70102 (I.A.U., O.N.C., V.N.C, M.?.T., I.V.G.), and by The Ministry of Education and Science of Russian Federation № 0124-2019-002 (R.V.S., N.D.A., B.A.M.)
- …