1,354 research outputs found
Половые отличия пула свободных аминокислот-нейромедиаторов у крыс Крушинского-Молодкиной
The study of the role of neurotransmitter systems in the pathogenesis of epilepsy is one of the priorities of epileptology. New data on the functions of free neurotransmitter-like amino acid in the central nervous system are of the greatest importance and determine the prospects for the development of novel effective anticonvulsants. It is widely believed in clinical medicine that epilepsy has distinct gender characteristics. The aim of this study was to investigate the gender peculiarities in the content of neurotransmitter amino acids in the brain of Krushinsky-Molodkina (KM) rats, which were used as model organisms for the study of genetically induced audiogenic epilepsy. The content of Asp, Glu, GABA, Gly, and Tau of the medulla oblongata, hippocampus and cerebral cortex were determined using high-performance liquid chromatography (HPLC) in intact KM rats, KM rats exposed to a series of epileptiform seizures, and Wistar rats (control group). Both the Wistar and KM rats had gender distinctions in the distribution of free amino acids among the investigated brain parts. The audiogenic epilepsy was characterized by smoothing gender differences as well as differences between the concentrations of free amino acids in the cortex and medulla oblongata, specific for Wistar rats. The changes observed in male rats after the set of seizures included the increase in GABA concentration and a decrease in the Gly level in all investigated brain parts, as well as the decrease of the Tau content in the cortex and hippocampus. At the same time, the Glu content in cortex increased, while the Asp level decreased. After 6 days of audiogenic stimulations the female KM rats demonstrated the increase in the Glu level in all investigated brain parts, the increase in Gly and Asp levels in hippocampus, and no changes in the GABA content. Thus, after the set of epileptiform seizures the KM rats achieved a new steady state of the studied amino acids pool, which differed in males and females. In this case, gender differences significantly changed after the seizures. © 2020 Russian Academy of Medical Sciences. All rights reserved.The work was performed within the framework of the state task of the IIF UB RAS (Registration number AAAA-A18-118020590108-7)
Type II Radio Emission and Solar Particle Observations
The 28 October 2003 flare gave us the unique opportunity to compare the
acceleration time of high-energy protons with the escaping time of those
particles which have been measured onboard spacecraft and by neutron monitors
network as GLE event. High-energy emission time scale and shock wave height and
velocity time dependencies were also studied.Comment: International Journal of Modern Physics A, Volume 20, Issue 29, pp.
6705-6707 (2005
Measurement of decay rate and parameters at KEDR
Using the inclusive photon spectrum based on a data sample collected at the
peak with the KEDR detector at the VEPP-4M collider, we
measured the rate of the radiative decay as well
as mass and width. Taking into account an asymmetric photon
lineshape we obtained keV, MeV/, MeV.Comment: 6 pages, 3 figure
Measurement of B(J/psi->eta_c gamma) at KEDR
We present a study of the inclusive photon spectrum from 6.3 million J/psi
decays collected with the KEDR detector at the VEPP-4M e+e- collider. We
measure the branching fraction of the radiative decay J/psi -> eta_c gamma,
eta_c width and mass. Taking into account an asymmetric photon line shape we
obtain: M(eta_c) = (2978.1 +- 1.4 +- 2.0) MeV/c^2, Gamma(eta_c) = (43.5 +- 5.4
+- 15.8) MeV, B(J/psi->eta_c gamma) = (2.59 +- 0.16 +- 0.31)%$.Comment: 6 pages, 1 figure. To be published in the proceedings of the 4th
International Workshop on Charm Physics (Charm2010), October 21-24, 2010,
IHEP, Beijin
Measurement of J/psi to eta_c gamma at KEDR
We present a study of the inclusive photon spectra from 5.9 million J/psi
decays collected with the KEDR detector at the VEPP-4M e+e- collider. We
measure the branching fraction of radiative decay J/psi to eta_c gamma, eta_c
width and mass. Our preliminary results are: M(eta_c) = 2979.4+-1.5+-1.9 MeV,
G(eta_c) = 27.8+-5.1+-3.3 MeV, B(J/psi to eta_c gamma) = (2.34+-0.15+-0.40)%.Comment: To be published in Proceedings of the PhiPsi09, Oct. 13-16, 2009,
Beijing, Chin
Interrelation of mast cells with spermatogenesis in norm and in case of damage
The aim of the study was to study the relationship between the condition of mast cells of testes and spermatogenesis in normal and with various types of testicular damage. Materials and methods. The studies were carried out on male rats of the Wistar line. Two experimental models of testicular damage were used puncture and compression. Morphological and morphometric methods of investigation were used to study the relationship between spermatogenesis and mast cells. To assess the functional state of the testicles by chemiluminescence, a study was made of the level of total testosterone in the blood. Results. The similar destructive processes develop in the testicle with various injuries, characterized by the presence of necrotic tubules, seed balls, a decrease in the number of spermatogenic epithelial cells, an increase in the number of non-functioning tubules, and a change in a number of morphometric parameters. The reaction of mast cells to various types of damage is manifested in the enhancement of their functional activity. So after a puncture against the background of a decrease in the number of mast cells activation of their synthetic function occurs, while in squeezing the cells respond not only with an increase in functional activity, but also with an increase in their number in the organ. The conclusion. Disturbance of spermatogenesis in various injuries of the testis is accompanied by activation of the functional activity of mast cells, regardless of the nature of the damage. However, the increase in the number of mast cells in the body occurs only with the preservation of the blood-testis barrier. Since normal spermatogenesis is carried out against the background of a sufficiently high synthetic activity of mast cells, this reaction of increased synthesis and degranulation can be considered as compensatory. © 2019 Siberian State Medical University. All rights reserved.to the publication of this article. Source of financing. The work was carried out as part of the government contract of the Institute of Immunology and Physiology, Russian Academy of Sciences (topic No. АААА-А18-118020590108-7)
Nitriding of titanium in electron beam excited plasma in medium vacuum
We report our results on nitriding of industrially-pure titanium VT1-0 in the plasma formed by continuous electron beam created by a fore-vacuum plasma-cathode electron source, at different temperatures of the titanium sample surface (700–1020 °C) and electron beam energy (4–6 keV), in medium vacuum (5 Pa) of nitrogen. Electron beam was used for direct treatment and heating of the sample as well as for the plasma generation. It is demonstrated that such parameters of the Ti sample as nitrogen content, the depth of nitride layer, Vickers microhardness, and wear-resistance grow with sample temperature and beam energy. Such positive effects happen, likely, due to enhanced generation of active atoms and atomic ions of nitrogen in beam-produced plasmas in medium vacuum
Electron beam nitriding of titanium in medium vacuum
We describe a novel method for electron-beam nitriding of metal (titanium) under medium (fore-vacuum)
pressures (2–8 Pa) of nitrogen. Titanium sample was heated by a dc electron beam generated by a fore-vacuum
plasma-cathode electron source with current up to 100 mA and energy up to 8 kV; this beam also generated
beam-produced plasma with active nitrogen atoms, ions and other reactive species near the sample. SEM chemical composition analysis of the nitride layer have shown the presence of approximately 25 wt% of N, wt. 68%
of Ti and only wt. 6% of O atoms within the processed layer. The X-ray diffraction spectrum of the nitride sample
showed that the modified layer has a crystalline structure predominantly orientated along the crystallographic
directions (111), (200), (220), characteristic of δ-TiN with a face-centered lattice. Besides the δ-TiN phase, there
are present in the nitrided layer a γ phase of Ti2N (tetragonal nitride) with predominant orientation (200). These
results show the advantage of using forevacuum sources for electron beam and plasma nitriding of metals
An Extreme Solar Event of 20 January 2005: Properties of the Flare and the Origin of Energetic Particles
The extreme solar and SEP event of 20 January 2005 is analyzed from two
perspectives. Firstly, we study features of the main phase of the flare, when
the strongest emissions from microwaves up to 200 MeV gamma-rays were observed.
Secondly, we relate our results to a long-standing controversy on the origin of
SEPs arriving at Earth, i.e., acceleration in flares, or shocks ahead of CMEs.
All emissions from microwaves up to 2.22 MeV line gamma-rays during the main
flare phase originated within a compact structure located just above sunspot
umbrae. A huge radio burst with a frequency maximum at 30 GHz was observed,
indicating the presence of a large number of energetic electrons in strong
magnetic fields. Thus, protons and electrons responsible for flare emissions
during its main phase were accelerated within the magnetic field of the active
region. The leading, impulsive parts of the GLE, and highest-energy gamma-rays
identified with pi^0-decay emission, are similar and correspond in time. The
origin of the pi^0-decay gamma-rays is argued to be the same as that of lower
energy emissions. We estimate the sky-plane speed of the CME to be 2000-2600
km/s, i.e., high, but of the same order as preceding non-GLE-related CMEs from
the same active region. Hence, the flare itself rather than the CME appears to
determine the extreme nature of this event. We conclude that the acceleration,
at least, to sub-relativistic energies, of electrons and protons, responsible
for both the flare emissions and the leading spike of SEP/GLE by 07 UT, are
likely to have occurred simultaneously within the flare region. We do not rule
out a probable contribution from particles accelerated in the CME-driven shock
for the leading GLE spike, which seemed to dominate later on.Comment: 34 pages, 14 Postscript figures. Solar Physics, accepted. A typo
corrected. The original publication is available at
http://www.springerlink.co
On inconsistency of experimental data on primary nuclei spectra with sea level muon intensity measurements
For the first time a complete set of the most recent direct data on primary
cosmic ray spectra is used as input into calculations of muon flux at sea level
in wide energy range GeV. Computations have been performed
with the CORSIKA/QGSJET and CORSIKA/VENUS codes. The comparison of the obtained
muon intensity with the data of muon experiments shows, that measurements of
primary nuclei spectra conform to sea level muon data only up to several tens
of GeV and result in essential deficit of muons at higher energies. As it
follows from our examination, uncertainties in muon flux measurements and in
the description of nuclear cascades development are not suitable to explain
this contradiction, and the only remaining factor, leading to this situation,
is underestimation of primary light nuclei fluxes. We have considered
systematic effects, that may distort the results of the primary cosmic ray
measurements with the application of the emulsion chambers. We suggest, that
re-examination of these measurements is required with the employment of
different hadronic interaction models. Also, in our point of view, it is
necessary to perform estimates of possible influence of the fact, that sizable
fraction of events, identified as protons, actually are antiprotons. Study of
these cosmic ray component begins to attract much attention, but today nothing
definite is known for the energies GeV. In any case, to realize whether
the mentioned, or some other reasons are the sources of disagreement of the
data on primaries with the data on muons, the indicated effects should be
thoroughly analyzed
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