868 research outputs found
INFLUENCE OF HYDROCORTISONE AND BETA-ADRENERGIC RECEPTOR BLOCKADE IN EFFECTOR PHASE OF THE IMMUNE RESPONSE ON PHAGOCYTIC ACTIVITY OF REGIONAL LYMPH NODE CELLS, BLOOD MONOCYTES AND PERITONEAL MACROPHAGES
It was established that hydrocortisone reduces the phagocytic activity of regional lymph node cells and peritoneal mononuclear phagocytes, but does not affect the relative parameters of the phagocytic activity of peripheral blood monocytes in the effector phase of immune response in rats. Effects of hydrocortisone were significantly modified by the administration of beta-adrenoceptor antagonist propranolol hydrochloride
IMMUNOMODULATORY EFFECT OF SOTALOL HYDROHLORIDE UNDER ACUTE STRESS
It was established that acute stress in period induction of the local and systemic immune response to thymus-dependent antigen caused an inhibition of expression of delayed-type hypersensitivity reactions, did not effect on antibody production in the regional lymph node under the local response and suppressed of antibody production in the spleen under the systemic immune response. Administration of sotalol hydrochloride (antagonist of beta-adrenoceptors with peripheral action) canceled these changes, that points to participate in their implementation of immunosuppressive signals from the peripheral beta-adrenergic receptors
ADRENERGIC REGULATION OF IMMUNE RESPONSE UNDER EXPERIMENTAL THYROTOXICOSIS IN RATS
It was established that a changes of antibody production and reaction of delayed—type hypersensitivity at the local immune response to thymus-dependent antigen were opposite in rats with varying severity of experimental thyrotoxicosis — stimulation under a mild form of thyrotoxicosis and depression under more severe form. The increase in glucocorticoid level may be involved in the mechanism of immunosuppression under severe form thyrotoxicosis. The administration of agonist or antagonist of beta-adrenoceptors to animals with thyrotoxicosis led to the significant modification of changes of an immune response parameters, that confirms the participation of an increase in the sensitivity to beta-adrenergic regulation of immune system cells in immunomodulation under thyrotoxicosis
Temperature dependence of self-trapped exciton luminescence in nanostructured hafnia powder
The intrinsic optical properties and peculiarities of the energy structure of
hafnium dioxide largely determine the prospects for applying the latter in new
generation devices of optoelectronics and nanoelectronics. In this work, we
have studied the diffuse reflectance spectra at room temperature for a
nominally pure nanostructured powder with a monoclinic crystal
structure and, as well its photoluminescence in the temperature range of 40 -
300 K. We have also estimated the bandgap under the assumption made for
indirect (5.31 eV) and direct (5.61 eV) allowed transitions. We have detected
emission with a 4.2 eV maximum at T < 200 K and conducted an analysis of the
experimental dependencies to evaluate the activation energies of thermal
quenching (140 meV) and enhancement (3 meV) processes. Accounting for both the
temperature behavior of the spectral characteristics and the estimation of the
Huang-Rhys factor S >> 1 has shown that radiative decay of self-trapped
excitons forms the mechanism of the indicated emission. In this case, the
localization is mainly due to the interaction of holes with active vibrational
modes of oxygen atoms in non-equivalent ( and ) crystal
positions. Thorough study of the discussed excitonic effects can advance
development of hafnia-based structures with a controlled optical response.Comment: 21 pages, 7 figures, 2 tables, 56 references. Keywords: hafnium
dioxide, self-trapped exciton, F-center, thermal quenching of luminescence,
luminescence enhacement, Huang-Rhys factor, effective phonon energy, bandgap
widt
Mutual Fund Theorem for continuous time markets with random coefficients
We study the optimal investment problem for a continuous time incomplete
market model such that the risk-free rate, the appreciation rates and the
volatility of the stocks are all random; they are assumed to be independent
from the driving Brownian motion, and they are supposed to be currently
observable. It is shown that some weakened version of Mutual Fund Theorem holds
for this market for general class of utilities; more precisely, it is shown
that the supremum of expected utilities can be achieved on a sequence of
strategies with a certain distribution of risky assets that does not depend on
risk preferences described by different utilities.Comment: 17 page
Clinical Experience of Luminescent Diagnostics of Precancerous Diseases and Cervical Cancer
The article summarizes the experience of using luminescent diagnostics with the use of ytterbium porphyrin complexes in gynecology and oncology. A pharmaceutical composition based on the Yb complex of 2,4-dimethoxyhematoporphyrin IX was used as the luminescent markers within the infrared range. The determination of luminescence characteristics (luminescence intensity) was carried out using a laserfiber fluorimeter in the range of 900-1100 nm. A new method for diagnosis of cervical disease has been proposed. The method of luminescent diagnostics allows to conduct a survey of a large number of patients in a short time. The method of luminescent diagnostics using the ytterbium complexes of porphyrins is not invasive. The method can be used as a screening. Differences between normal and pathologically altered cervical tissue have been identified and differences between pathological changes in the cervix HSIL (CIN II, CIN III) and cervical cancer are reliable.
Keywords: Cervical cancer, squamous cell carcinoma, diagnosis of cervical cancer, squamous intraepithelial lesions of high grade – HSIL, luminescent diagnostics, luminescing in the near infrared (NIR) spectral region, porphyrins, ytterbium complexes of porphyrins
Crystal structure, Fermi surface calculations and Shubnikov-de Haas oscillations spectrum of the organic metal -(BETS)HgBr(CHCl) at low temperature
The organic metal \theta_4_4_6_5$Cl) is known to
undergo a phase transition as the temperature is lowered down to about 240 K.
X-ray data obtained at 200 K indicate a corresponding modification of the
crystal structure, the symmetry of which is lowered from quadratic to
monoclinic. In addition, two different types of cation layers are observed in
the unit cell. The Fermi surface (FS), which can be regarded as a network of
compensated electron and hole orbits according to band structure calculations
at room temperature, turns to a set of two alternating linear chains of orbits
at low temperature. The field and temperature dependence of the Shubnikov-de
Haas oscillations spectrum have been studied up to 54 T. Eight frequencies are
observed which, in any case, points to a FS much more complex than predicted by
band structure calculations at room temperature, even though some of the
observed Fourier components might be ascribed to magnetic breakdown or
frequency mixing. The obtained spectrum could result from either an interaction
between the FS's linked to each of the two cation layers or to an eventual
additional phase transition in the temperature range below 200 K.Comment: accepted for publication in Solid State Science
Frequency Dispersion of Sound Propagation in Rouse Polymer Melts via Generalized Dynamic Random Phase Approximation
An extended generalization of the dynamic random phase approximation (DRPA)
for L-component polymer systems is presented. Unlike the original version of
the DRPA, which relates the (LxL) matrices of the collective density-density
time correlation fumctions and the corresponding susceptibilities of polymer
concentrated systems to those of the tracer macromolecules and so-called broken
links system (BLS), our generalized DRPA solves this problem for (5xL)x(5xL)
matrices of the coupled susceptibilities and time correlation functions of the
component number, kinetic energy and flux densities. The presented technique is
used to study propagation of sound and dynamic form-factor in disentangled
(Rouse) monodisperse homopolymer melt. The calculated sound velocity and
absorption coefficient reveal substantial frequency dispersion. The relaxation
time is found to be N times less than the Rouse time (N is the degree of
polymerization), which evidences strong dynamic screening because of interchain
interaction. We discuss also some peculiarities of the Brillouin scattering in
polymer melts. Besides, a new convenient expression for the dynamic structural
function of the Rouse chain in (q,p)-representation is found.Comment: 37 pages, 2 appendices, 48 references, 1 figur
- …