1,567 research outputs found
Bypassing damaged nervous tissue
It is shown the principal possibility of bypassing damaged demyelinated
portions of the nervous tissue, thereby restoring its normal function for the
passage of action potentials
Ponderomotive perturbations of low density low-temperature plasma under laser Thomson scattering diagnostics
The ponderomotive perturbation in the interaction region of laser radiation
with a low density and low-temperature plasma is considered. Estimates of the
perturbation magnitude are determined from the plasma parameters, geometry,
intensity and wavelength of laser radiation. It is shown that ponderomotive
perturbations can lead to large errors in the electron density when measured
using Thomson scattering
Literature survey on low rank approximation of matrices
Low rank approximation of matrices has been well studied in literature.
Singular value decomposition, QR decomposition with column pivoting, rank
revealing QR factorization (RRQR), Interpolative decomposition etc are
classical deterministic algorithms for low rank approximation. But these
techniques are very expensive operations are required for matrices). There are several randomized algorithms available in the
literature which are not so expensive as the classical techniques (but the
complexity is not linear in n). So, it is very expensive to construct the low
rank approximation of a matrix if the dimension of the matrix is very large.
There are alternative techniques like Cross/Skeleton approximation which gives
the low-rank approximation with linear complexity in n . In this article we
review low rank approximation techniques briefly and give extensive references
of many techniques
Non-thermal influence of a weak microwave on nerve fiber activity
This paper presents a short selective review of the non-thermal weak
microwave field impact on a nerve fiber. The published results of recent
experiments are reviewed and analyzed. The theory of the authors is presented,
according to which there are strongly pronounced resonances in the range of
about 30-300 GHz associated with the excitation of ultrasonic vibrations in the
membrane as a result of interactions with the microwave radiation. These forced
vibrations create acoustic pressure, which may lead to the redistribution of
the protein transmembrane channels, thus changing the threshold of the action
potential excitation in the axons of the neural network. The problem of surface
charge on the bilayer lipid membrane of the nerve fiber is discussed. Various
experiments for observing the effects considered are also discussed.Comment: arXiv admin note: text overlap with arXiv:1309.594
On the possible mechanisms of the selective effect of a non-equilibrium plasma on healthy and cancer cells in a physiological solution
This paper discusses possible mechanisms for the selective effect of weakly
ionized non-equilibrium plasma and currents in electrolyte on healthy and
cancerous cells in physiological saline in a Petri dish. The interaction with
the plasma source leads to a change in osmotic pressure, which affects the
electro-mechanical properties of cell membranes in healthy and cancerous cells
in different ways. The currents arising in the electrolyte charge the membranes
of healthy and cancerous cells to a different potential difference due to the
different values of the membranes' dielectric constant. We hypothesized that
the dielectric permeability of cancer cell membranes is lower than that of
healthy cells, as is the capacity of a unit of the membrane surface, and
therefore, the additional potential difference acquired by the membrane through
charging with currents induced in the intercellular electrolyte is greater in
cancer cells. This can lead to electroporation of cancer cell membranes,
resulting in their apoptosis, but does not effect healthy cells
Initiation and blocking of the action potential in the axon in weak ultrasonic or microwave fields
In this paper, we analyze the effect of the redistribution of the
transmembrane ion channels in the axon caused by longitudinal acoustic
vibrations of the membrane. These oscillations can be excited by an external
source of ultrasound and weak microwave radiation interacting with the charges
sitting on the surface of the lipid membrane. It is shown, using the
Hodgkin-Huxley model of the axon, that the density redistribution of
transmembrane sodium channels may reduce the threshold of the action potential,
up to its spontaneous initiation. At the significant redistribution of sodium
channels in membrane, the rarefaction zones of the transmembrane channels
density are formed, blocking the propagation of the action potential. Blocking
the action potential propagation along the axon is shown to cause anestesia in
the example case of a squid axon. Various approaches to experimental
observation of the effects considered in this paper are discussed
Cavitation near the oscillating piezoelectric plate in water
It is known that gas bubbles on the surface bounding a fluid flow can change
the coefficient of friction and affect the parameters of the boundary layer. In
this paper, we propose a method that allows us to create, in the near-wall
region, a thin layer of liquid filled with bubbles. It will be shown that if
there is an oscillating piezoelectric plate on the surface bounding a liquid,
then, under certain conditions, cavitation develops in the boundary layer. The
relationship between the parameters of cavitation and the characteristics of
the piezoelectric plate oscillations is obtained. Possible applications are
discussed
Surface tension of small bubbles and droplets and the cavitation threshold
In this paper, using an unified approach, estimates are given of the
magnitude of the surface tension of water for planar and curved interfaces in
the pairwase interaction approximation based on the Lennard-Jones potential. It
is shown that the surface tensions of a bubble and droplet have qualitatively
different dependences on the curvature of the surface: for the bubble, as the
radius of the surface's curvature decreases, the surface tension decreases,
whereas it increases on the droplet. The corresponding values of the Tolman
corrections are also determined. In addition, it is shown that the dependence
of the surface tension on the surface's curvature is important for evaluating
the critical negative pressure for the onset of cavitation
Cavitation nanopore in the dielectric fluid in the inhomogeneous, pulsed electric fields
This paper discusses the nanopores emerging and developing in a liquid
dielectric under the action of the ponderomotive electrostrictive forces in a
nonuniform electric field. It is shown that the gradient of the electric field
in the vicinity of the rupture (cavitation nanopore) substantially increases
and determines whether the rupture grows or collapses. The cavitation rupture
in the liquid (nanopore) tends to stretch along the lines of the original
field. The mechanism of the breakdown associated with the generation of
secondary ruptures in the vicinity of the poles of the nanopore is proposed.
The estimations of the extension time for nanopore in water and oil (polar and
nonpolar liquids, respectively) are presented. A new mechanism of nano- and
subnanosecond breakdown in the insulating (transformer) oil that can be
realized in the vicinity of water microdroplets in modern nanosecond
high-voltage devices is considere
Initial stage of cavitation in liquids and its observation by Rayleigh scattering
A theory is developed for the initial stage of cavitation in the framework of
Zel'dovich-Fisher theory of nucleation in the field of negative pressure, while
taking into account the surface tension dependence on the nanopore radius. A
saturation mechanism is proposed that limits the exponential dependence of the
nucleation rate on the energy required to create nanopores. An estimate of the
saturated density of nanopores at the nucleation stage is obtained. It is shown
that Rayleigh scattering can detect nanopores arising at the initial stage of
cavitation development
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