205 research outputs found
Dysfunction of Neuromuscular Synapses in the Genetic Model of Alzheimer’s Disease
© 2018, Springer Science+Business Media, LLC, part of Springer Nature. The function of synaptic transmission and presynaptic vesicular cycle in the neuromuscular synapses of the diaphragm was studied in transgenic APP/PS1 mice (Alzheimer’s disease model). The decrease in the quantal content of end-plate potential, intense depression of the amplitude of terminal plate potentials under conditions of lasting high frequency stimulation (50 Hz), a drastic prolongation of the synaptic vesicle recycling time in APP/PS1 mice in comparison with wild type mice were detected. Manifest dysfunction of the neuromuscular synapses, caused by disordered neurosecretion and recycling of the synaptic vesicles in the presynaptic nerve endings, was detected in the Alzheimer’s disease model on transgenic APP/PS1 mice. The study supplemented the notions on the pathogenesis of Alzheimer’s disease as a systemic disease, while the detected phenomena could just partially explain the development of motor disorders in this disease
On The Mobile Behavior of Solid He at High Temperatures
We report studies of solid helium contained inside a torsional oscillator, at
temperatures between 1.07K and 1.87K. We grew single crystals inside the
oscillator using commercially pure He and He-He mixtures containing
100 ppm He. Crystals were grown at constant temperature and pressure on the
melting curve. At the end of the growth, the crystals were disordered,
following which they partially decoupled from the oscillator. The fraction of
the decoupled He mass was temperature and velocity dependent. Around 1K, the
decoupled mass fraction for crystals grown from the mixture reached a limiting
value of around 35%. In the case of crystals grown using commercially pure
He at temperatures below 1.3K, this fraction was much smaller. This
difference could possibly be associated with the roughening transition at the
solid-liquid interface.Comment: 15 pages, 6 figure
Investigation of the Chaotic Dynamics of an Electron Beam with a Virtual Cathode in an External Magnetic Field
The effect of the strength of the focusing magnetic field on chaotic dynamic
processes occurring inan electron beam with a virtual cathode, as well as on
the processes whereby the structures form in the beamand interact with each
other, is studied by means of two-dimensional numerical simulations based on
solving a self-consistent set of Vlasov-Maxwell equations. It is shown that, as
the focusing magnetic field is decreased,the dynamics of an electron beam with
a virtual cathode becomes more complicated due to the formation andinteraction
of spatio-temporal longitudinal and transverse structures in the interaction
region of a vircator. The optimum efficiency of the interaction of an electron
beam with the electromagnetic field of the vircator isachieved at a
comparatively weak external magnetic field and is determined by the
fundamentally two-dimensional nature of the motion of the beam electrons near
the virtual cathode.Comment: 12 pages, 8 figure
Self-similar solution of a nonsteady problem of nonisothermal vapour condensation on a droplet growing in diffusion regime
This paper presents a mathematically exact self-similar solution to the joint
nonsteady problems of vapour diffusion towards a droplet growing in a
vapour-gas medium and of removal of heat released by a droplet into a
vapour-gas medium during vapour condensation. An equation for the temperature
of the droplet is obtained; and it is only at that temperature that the
self-similar solution exists. This equation requires the constancy of the
droplet temperature and even defines it unambiguously throughout the whole
period of the droplet growth. In the case of strong display of heat effects,
when the droplet growth rate decreases significantly, the equation for the
temperature of the droplet is solved analytically. It is shown that the
obtained temperature fully coincides with the one that settles in the droplet
simultaneously with the settlement of its diffusion regime of growth. At the
obtained temperature of the droplet the interrelated nonsteady vapour
concentration and temperature profiles of the vapour-gas medium around the
droplet are expressed in terms of initial (prior to the nucleation of the
droplet) parameters of the vapour-gas medium. The same parameters are used to
formulate the law in accordance with which the droplet is growing in diffusion
regime, and also to define the time that passes after the nucleation of the
droplet till the settlement of diffusion regime of droplet growth, when the
squared radius of the droplet becomes proportionate to time. For the sake of
completeness the case of weak display of heat effects is been studied.Comment: 12 pages, 4 figure
Test of exotic scalar and tensor interactions in K_e3 decay using stopped positive kaons
The form factors of the decay K+ --> pi0 e+ nu (K_e3) have been determined
from the comparison of the experimental and Monte Carlo Dalitz distributions
containing about 10^5 K_e3 events. The following values of the parameters were
obtained: lambda_+ = 0.0278 +- 0.0017(stat) +- 0.0015(syst), f_S/f_+(0) =
0.0040 +- 0.0160(stat) +- 0.0067(syst) and f_T/f_+(0) = 0.019 +- 0.080(stat) +-
0.038(syst). Both scalar f_S and tensor f_T form factors are consistent with
the Standard Model predictions of zero values.Comment: 10 pages, 5 figures, contributed to the proceedings of NANP
Conference, Dubna, June 19-23, 200
ПЕРСИСТЕНТНОСТЬ МИКРОФИЛЯРИЦИДНОГО ДЕЙСТВИЯ АВЕРСЕКТА КОМБИ ПРИ ОНХОЦЕРКОЗЕ И СЕТАРИОЗЕ КРУПНОГО РОГАТОГО СКОТА
Persistent effect of aversect combi against microfilaria Onchocerca spp. and Setaria spp. is studied. The drug in therapeutic dose of 0,2 mg/kg showed persistence effect during 4–6 months.Изучена персистентность действия аверсекта комби против микрофилярий Onchocerca spp. и Setaria spp. Препарат в терапевтической дозе 0,2 мг/кг обладает персистентным в течение 4–6 месяцев действием против микрофилярий
Defects and glassy dynamics in solid He-4: Perspectives and current status
We review the anomalous behavior of solid He-4 at low temperatures with
particular attention to the role of structural defects present in solid. The
discussion centers around the possible role of two level systems and structural
glassy components for inducing the observed anomalies. We propose that the
origin of glassy behavior is due to the dynamics of defects like dislocations
formed in He-4. Within the developed framework of glassy components in a solid,
we give a summary of the results and predictions for the effects that cover the
mechanical, thermodynamic, viscoelastic, and electro-elastic contributions of
the glassy response of solid He-4. Our proposed glass model for solid He-4 has
several implications: (1) The anomalous properties of He-4 can be accounted for
by allowing defects to freeze out at lowest temperatures. The dynamics of solid
He-4 is governed by glasslike (glassy) relaxation processes and the
distribution of relaxation times varies significantly between different
torsional oscillator, shear modulus, and dielectric function experiments. (2)
Any defect freeze-out will be accompanied by thermodynamic signatures
consistent with entropy contributions from defects. It follows that such
entropy contribution is much smaller than the required superfluid fraction, yet
it is sufficient to account for excess entropy at lowest temperatures. (3) We
predict a Cole-Cole type relation between the real and imaginary part of the
response functions for rotational and planar shear that is occurring due to the
dynamics of defects. Similar results apply for other response functions. (4)
Using the framework of glassy dynamics, we predict low-frequency yet to be
measured electro-elastic features in defect rich He-4 crystals. These
predictions allow one to directly test the ideas and very presence of glassy
contributions in He-4.Comment: 33 pages, 13 figure
Directed Synthesis of Crystalline Plutonium(III) and (IV) Oxalates: Accessing Redox-Controlled Separations in Acidic Solutions
Epizootic Activity of Natural Plague Foci in the Territory of the Russian Federation in 2014 and Prognosis for 2015
. Isolated were 128 plague agent strains: from rodents and lagomorphs - 24, 103 - from bloodsucking arthropods. One strain was obtained from a patient in the territory of Gorno-Altaisk high-mountain natural plague focus. Substantiated has been epizootiological prognosis claiming persistent challenging epidemiological situation in the foci. Outlined is the necessity to use epizootiological forecasting as the basis for scheduling and carrying out epidemiological monitoring and preventive measures in active natural plague foci. Due to the varying epidemiological significance of Y. pestis ssp. pestis , Y. pestis ssp. caucasica , and Y. pestis ssp. altaica strains the data on their spatial distribution should be deployed for differentiation of focal areas according to the degree of the potential epidemic hazard
Epizootic Activity of Natural Plague Foci of the Russian Federation in 2015, and Prognosis for 2016
Objective of the study is to evaluate the state of parasitic systems and activity of natural plague foci of the Russian Federation in 2015 and to develop epizootiological forecast for 2016. In 2015, plague epizooties were detected in the territory of Gorno-Altaisk high-mountain, Tuva mountain, and Pre-Caspian sandy natural plague foci with a total area amounting to 1573.4 square kilometers. Isolated were 46 strains of plague microbe, including the isolates from rodents and leporines - 18, and from fleas - 28. Substantiated is epizootiological prognosis for sustaining challenging epidemiological situation in Gorno-Altaisk high-mountain and Tuva mountain natural foci in 2016. Demonstrated is the fact that consequently to effective prompt prophylactic measures (field deratization, disinsection) in 2015 decreased epizootic activity of Pre-Caspian sandy focus is observed. Specified is retention of low numbers of carriers and vectors of plague in natural foci of North and North-Western Caspian Sea Region, Pre-Caucasian, Caucasian, and Transbaikal Territories. Identified is upward trend for numbers of the little souslik in Pre-Caspian North-Western steppe, Volga-Ural steppe, Dagestan lowland-piedmont, and Pre-Caspian sandy natural plague foci
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