51,163 research outputs found
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
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
On Chow weight structures for -motives with integral coefficients
The main goal of this paper is to define a certain Chow weight structure
on the category of (constructible) -motives over an
equicharacteristic scheme . In contrast to the previous papers of D.
H\'ebert and the first author on weights for relative motives (with rational
coefficients), we can achieve our goal for motives with integral coefficients
(if ; if then we consider
motives with -coefficients). We prove that the
properties of the Chow weight structures that were previously established for
-linear motives can be carried over to this "integral" context (and
we generalize some of them using certain new methods). In this paper we mostly
study the version of defined via "gluing from strata"; this enables
us to define Chow weight structures for a wide class of base schemes.
As a consequence, we certainly obtain certain (Chow)-weight spectral
sequences and filtrations for any (co)homology of motives.Comment: To appear in Algebra i Analiz (St. Petersburg Math Journal). arXiv
admin note: substantial text overlap with arXiv:1007.454
Inverse dispersion method for calculation of complex photonic band diagram and -symmetry
We suggest an inverse dispersion method for calculating photonic band diagram
for materials with arbitrary frequency-dependent dielectric functions. The
method is able to calculate the complex wave vector for a given frequency by
solving the eigenvalue problem with a non-Hermitian operator. The analogy with
-symmetric Hamiltonians reveals that the operator corresponds to the
momentum as a physical quantity and the singularities at the band edges are
related to the branch points and responses for the features on the band edges.
The method is realized using plane wave expansion technique for two-dimensional
periodical structure in the case of TE- and TM-polarization. We illustrate the
applicability of the method by calculation of the photonic band diagrams of an
infinite two-dimension square lattice composed of dielectric cylinders using
the measured frequency dependent dielectric functions of different materials
(amorphous hydrogenated carbon, silicon, and chalcogenide glass). We show that
the method allows to distinguish unambiguously between Bragg and Mie gaps in
the spectra.Comment: 8 pages, 5 figure
Proof of Gal's conjecture for the D series of generalized associahedra
In this short note we consider generalized associahedra of type D_n. We prove
that these simple flag polytopes are not nestohedra for n > 3, but the
statement of Gal's conjecture holds for them
De Rham theorem for extended L^2-cohomology
We prove an analogue of the de Rham theorem for the extended L^2-cohomology
introduced by M. Farber. This is done by establishing that the de Rham complex
over a compact closed manifold with coefficients in a flat Hilbert bundle E of
A-modules over a finite von Neumann algebra A is chain-homotopy equivalent
(with bounded morphisms and homotopy operators) to a combinatorial complex with
the same coefficients. This is established by using the Witten deformation of
the de Rham complex. We also prove that the de Rham complex is chain-homotopy
equivalent to the spectrally truncated de Rham complex which is also finitely
generated.Comment: 16 pages, author-supplied file available at
ftp://ftp.math.neu.edu/Pub/faculty/Shubin_Mikhail/papers/DR19.tex This is a
slight revision -- some references are added AMSTeX v 2.
An upper bound for the Hales-Jewett number HJ(4,2)
We show that for at least , any 2-coloring of the
-dimensional grid contains a monochromatic combinatorial line. This
is a special case of the Hales-Jewett Theorem, to which the best known general
upper bound is due to Shelah; Shelah's recursion gives an upper bound between
and for the case we consider,
and no better value was previously known
Magnetic behaviour of dirty multiband superconductors near the upper critical field
Magnetic properties of dirty multiband superconductors near the upper
critical field are studied. The parameter characterizing
magnetization slope is shown to have a significant temperature variation which
is quite sensitive to the pairing interactions and relative strengths of
intraband impurity scattering. In contrast to single-band superconductors the
increase of at low temperatures can be arbitrary large determined by
the ratio of minimal and maximal diffusion coefficients in different bands.
Temperature dependencies of in two-band MgB and iron-based
superconductors are shown to be much more sensitive to the multiband effects
than the upper critical field
Direct and inverse scattering on noncompact star-type quantum graph with Bessel singularity
In this paper we study the noncompact star-type graph with perturbed radial
Schrodinger equation on each ray and the matching conditions of some special
form at the vertex. The results include the uniqueness theorem and constructive
procedure for solution of the inverse scattering problem
On differential polynomial rings over locally nilpotent rings
Let be a derivation of a locally nilpotent ring . Then the
differential polynomial ring cannot be mapped onto a ring with a
non-zero idempotent. This answers a recent question by Greenfeld, Smoktunowicz
and Ziembowski
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