2,216 research outputs found
Cough. The place of herbal medicine in treatment
Cough is one of the auxiliary mechanisms for cleaning the airways from mucus, foreign particles, microorganisms. The physiological cough reflex allows the mechanism of airway cleansing, provided that mucociliary clearance works sufficiently. However, sometimes the cough loses its protective function, becomes persistent, and impairs the quality of life of the patient. In this regard, in the treatment of cough, attention is paid to both secretomotor and secretolytic therapy. Medicinal plants are among the drugs with such properties. Numerous group of drugs containing herbal components has a reflex action, which allows coping most effectively with cough in the initial stages of diseases accompanied by respiratory symptoms. The most common among them and widely used are plantain leaf, coltsfoot leaf, thermopsis herb, ipecacuanha root, marshmallow root, licorice root, anise fruit, thyme (thyme) herb extract, ivy leaf extract. A well-known drug, the active ingredient of which is ivy leaf extract. Its mechanism of action consists in increasing the production of surfactant and increasing the number of β2-adrenoreceptors on the surface of alveolar cells of the bronchial tree, to which ivy active substance α-hederin is attached, which has a bronchospasmodic and expectorant action. Numerous clinical studies have proven a high efficacy and safety of the product based on ivy leaf extract, which allows us to recommend it as the drug of choice for symptomatic cough therapy in both children and adults during acute respiratory infections
Survey of charge symmetry breaking operators for dd -> alpha pi0
The charge-symmetry-breaking amplitudes for the recently observed d d ->
alpha pi0 reaction are investigated. Chiral perturbation theory is used to
classify and identify the leading-order terms. Specific forms of the related
one- and two-body tree level diagrams are derived. As a first step toward a
full calculation, a few tree-level two-body diagrams are evaluated at each
considered order, using a simplified set of d and alpha wave functions and a
plane-wave approximation for the initial dd state. The leading-order
pion-exchange term is shown to be suppressed in this model because of poor
overlap of the initial and final states. The higher-order one-body and
short-range (heavy-meson-exchange) amplitudes provide better matching between
the initial and final states and therefore contribute significantly and
coherently to the cross section. The consequences this might have for a full
calculation, with realistic wave functions and a more complete set of
amplitudes, are discussed.Comment: REVTeX 4, 35 pages, 8 eps figures, submitted to PR
Impact of saturation on spin effects in proton-proton scattering
For pomerons described by a sum of two simple-pole terms, a soft and a hard
pomeron, the unitarity bounds from saturation in impact-parameter space are
examined. We consider the effect of these bounds on observables linked with
polarisation, such as the analyzing power in elastic proton-proton scattering,
for LHC energies. We obtain the s and t dependence of the Coulomb-nuclear
interference at small momentum transfer, and show that the effect of the hard
pomeron may be observed at the LHC.Comment: 8 pages, 2 figures, presented by O.V.S. at the Advanced Studies
Institute "Symetries and Spin" (SPIN-Praha-2004), Prague, July 5 - July 10,
200
Z topology and superconductivity from symmetry lowering of a 3D Dirac Metal AuPb
3D Dirac semi-metals (DSMs) are materials that have massless Dirac electrons
and exhibit exotic physical properties It has been suggested that structurally
distorting a DSM can create a Topological Insulator (TI), but this has not yet
been experimentally verified. Furthermore, quasiparticle excitations known as
Majorana Fermions have been theoretically proposed to exist in materials that
exhibit superconductivity and topological surface states. Here we show that the
cubic Laves phase AuPb has a bulk Dirac cone above 100 K that gaps out upon
cooling at a structural phase transition to create a topologically non trivial
phase that superconducts below 1.2 K. The nontrivial Z = -1 invariant in
the low temperature phase indicates that AuPb in its superconducting state
must have topological surface states. These characteristics make AuPb a
unique platform for studying the transition between bulk Dirac electrons and
topological surface states as well as studying the interaction of
superconductivity with topological surface states
CrOx/SiO2 catalysts prepared by metal vapour synthesis: physical-chemical characterisation and functional testing in oxidative dehydrogenation of propane
Nucleon Polarizibilities for Virtual Photons
We generalize the sum rules for the nucleon electric plus magnetic
polarizability and for the nucleon spin-polarizability
, to virtual photons with . The dominant low energy cross
sections are represented in our calculation by one-pion-loop graphs of
relativistic baryon chiral perturbation theory and the -resonance
excitation. For the proton we find good agreement of the calculated
with empirical values obtained from integrating up
electroproduction data for . The proton spin-polarizability
switches sign around and it joins smoothly the
"partonic" curve, extracted from polarized deep-inelastic scattering, around
. For the neutron our predictions of and
agree reasonably well at with existing determinations.
Upcoming (polarized) electroproduction experiments will be able to test the
generalized polarizability sum rules investigated here.Comment: 12 pages, 5 figures, submittes to Nuclear Physics
The effects of the small t properties of hadronic scattering amplitude on the determination its real part
Taking into account the different forms of the Coulomb-hadron interference
phase and the possible spin-flip contribution the new analysis of the
experimental data of the proton-antiproton elastic scattering at GeV/c and small momentum transfer is carried out. It is shown that the
size of the spin-flip amplitude can be determined from the form of the
differential cross sections at small , and the deviation of
obtained from the examined experimental data of the scattering from
the analysis \cite{Kroll}, based on the dispersion relations, is conserved in
all xamined assumptions. The analysis of the proton-proton elastic scattering
at GeV/c also shows the impact of the examined effects on the
form of the differential cross sections.Comment: 13 pages, 3 figure
Mechanisms for High-frequency QPOs in Neutron Star and Black Hole Binaries
We explain the millisecond variability detected by Rossi X-ray Timing
Explorer (RXTE) in the X-ray emission from a number of low mass X-ray binary
systems (Sco X-1, 4U1728-34, 4U1608-522, 4U1636-536, 4U0614+091, 4U1735-44,
4U1820-30, GX5-1 and etc) in terms of dynamics of the centrifugal barrier, a
hot boundary region surrounding a neutron star. We demonstrate that this region
may experience the relaxation oscillations, and that the displacements of a gas
element both in radial and vertical directions occur at the same main
frequency, of order of the local Keplerian frequency. We show the importance of
the effect of a splitting of the main frequency produced by the Coriolis force
in a rotating disk for the interpretation of a spacing between the QPO peaks.
We estimate a magnitude of the splitting effect and present a simple formula
for the whole spectrum of the split frequencies. It is interesting that the
first three lowest-order overtones fall in the range of 200-1200 Hz and match
the kHz-QPO frequencies observed by RXTE. Similar phenomena should also occur
in Black Hole (BH) systems, but, since the QPO frequency is inversely
proportional to the mass of a compact object, the frequency of the
centrifugal-barrier oscillations in the BH systems should be a factor of 5-10
lower than that for the NS systems. The X-ray spectrum formed in this region is
a result of upscattering of a soft radiation (from a disk and a NS surface) off
relatively hot electrons in the boundary layer. We also briefly discuss some
alternative QPO models, including a possibility of acoustic oscillations in the
boundary layer, the proper stellar rotation, and g-mode disk oscillations.Comment: The paper is coming out in the Astrophysical Journal in the 1st of
May issue of 199
Coulomb-hadron phase factor and spin phenomena in a wide region of transfer momenta
The Coulomb-hadron interference effects are examined at small and large .
The methods for the definition of spin-dependent parts of hadron scattering
amplitude are presented. The additional contributions to analyzing power
and the double spin correlation parameter owing to the
electromagnetic-hadron interference are determined in the diffraction dip
domain of high-energy elastic hadron scattering.Comment: 9 pages, LaTeX, 4 figure
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