202 research outputs found
INTERVENTION EFFECT AND DOSE-DEPENDENT RESPONSE OF TANREQING INJECTION ON AIRWAY MUCUS HYPERSECRETION IN LIPOPOLYSACCHARIDE-INDUCED RATS
Background: Tanreqing injection, a Chinese herbal formulation comprising Radix Scutellariae, Fructus Forsythiae, Flos Lonicerae, Antelope horn, and Bear bile powder, has been used to treat bronchitis and pneumonia for many years in China. However, its anti-mucus-hypersecretion mechanism has yet not been fully interpreted. We aim to assess the effect and dose-response relationships of Tanreqing injection on lipopolysacchaide (LPS) induced airway mucus hypersecretion in rats.
Material and methods: Forty-eight male rats were randomly divided into four groups (12 per group). A rat model of airway mucus hypersecretion was generated with LPS. Tanreqing injection was given by intratracheal instillation, and bronchoalveolar lavage fluid (BALF) from the right lung was collected. BALF total protein was determined by bicinchoninic acid disodium assay (BCA). Muc5ac was measured using enzyme linked immunosorbent assay (ELISA) and immunohistochemistry. The expression of muc5ac mRNA was detected by real-time polyermase chain reaction (RT-PCR). The middle lobe of the right lung was stained with alcian blue-periodic acid sthiff (AB-PAS) and positive staining relative shading area examined.
Results: LPS caused airway mucus hypersecretion, The LPS-induced airway mucus hypersecretion increased beginning at 24 hr, and peaked at 96 hr. Tanreqing injection could inhibit airway mucus hypersecretion, and suppress the expression of muc5ac mRNA.
Conclusion: Tanreqing injection inhibits airway mucus hypersecretion in a certain dose-dependent trend
Landau Quantization of Massless Dirac Fermions in Topological Insulator
The recent theoretical prediction and experimental realization of topological
insulators (TI) has generated intense interest in this new state of quantum
matter. The surface states of a three-dimensional (3D) TI such as Bi_2Te_3,
Bi_2Se_3 and Sb_2Te_3 consist of a single massless Dirac cones. Crossing of the
two surface state branches with opposite spins in the materials is fully
protected by the time reversal (TR) symmetry at the Dirac points, which cannot
be destroyed by any TR invariant perturbation. Recent advances in thin-film
growth have permitted this unique two-dimensional electron system (2DES) to be
probed by scanning tunneling microscopy (STM) and spectroscopy (STS). The
intriguing TR symmetry protected topological states were revealed in STM
experiments where the backscattering induced by non-magnetic impurities was
forbidden. Here we report the Landau quantization of the topological surface
states in Bi_2Se_3 in magnetic field by using STM/STS. The direct observation
of the discrete Landau levels (LLs) strongly supports the 2D nature of the
topological states and gives direct proof of the nondegenerate structure of LLs
in TI. We demonstrate the linear dispersion of the massless Dirac fermions by
the square-root dependence of LLs on magnetic field. The formation of LLs
implies the high mobility of the 2DES, which has been predicted to lead to
topological magneto-electric effect of the TI.Comment: 15 pages, 4 figure
Pairing symmetry and properties of iron-based high temperature superconductors
Pairing symmetry is important to indentify the pairing mechanism. The
analysis becomes particularly timely and important for the newly discovered
iron-based multi-orbital superconductors. From group theory point of view we
classified all pairing matrices (in the orbital space) that carry irreducible
representations of the system. The quasiparticle gap falls into three
categories: full, nodal and gapless. The nodal-gap states show conventional
Volovik effect even for on-site pairing. The gapless states are odd in orbital
space, have a negative superfluid density and are therefore unstable. In
connection to experiments we proposed possible pairing states and implications
for the pairing mechanism.Comment: 4 pages, 1 table, 2 figures, polished versio
High non-photonic electron production in + collisions at = 200 GeV
We present the measurement of non-photonic electron production at high
transverse momentum ( 2.5 GeV/) in + collisions at
= 200 GeV using data recorded during 2005 and 2008 by the STAR
experiment at the Relativistic Heavy Ion Collider (RHIC). The measured
cross-sections from the two runs are consistent with each other despite a large
difference in photonic background levels due to different detector
configurations. We compare the measured non-photonic electron cross-sections
with previously published RHIC data and pQCD calculations. Using the relative
contributions of B and D mesons to non-photonic electrons, we determine the
integrated cross sections of electrons () at 3 GeV/10 GeV/ from bottom and charm meson decays to be = 4.0({\rm
stat.})({\rm syst.}) nb and =
6.2({\rm stat.})({\rm syst.}) nb, respectively.Comment: 17 pages, 17 figure
Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at GeV
We present first measurements of the evolution of the differential transverse
momentum correlation function, {\it C}, with collision centrality in Au+Au
interactions at GeV. {\it C} exhibits a strong dependence
on collision centrality that is qualitatively similar to that of number
correlations previously reported. We use the observed longitudinal broadening
of the near-side peak of {\it C} with increasing centrality to estimate the
ratio of the shear viscosity to entropy density, , of the matter formed
in central Au+Au interactions. We obtain an upper limit estimate of
that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.
Measurements of Dihadron Correlations Relative to the Event Plane in Au+Au Collisions at GeV
Dihadron azimuthal correlations containing a high transverse momentum (\pt)
trigger particle are sensitive to the properties of the nuclear medium created
at RHIC through the strong interactions occurring between the traversing parton
and the medium, i.e. jet-quenching. Previous measurements revealed a strong
modification to dihadron azimuthal correlations in Au+Au collisions with
respect to \pp\ and \dAu\ collisions. The modification increases with the
collision centrality, suggesting a path-length dependence to the jet-quenching
effect. This paper reports STAR measurements of dihadron azimuthal correlations
in mid-central (20-60\%) Au+Au collisions at \snn=200~GeV as a function of
the trigger particle's azimuthal angle relative to the event plane,
\phis=|\phit-\psiEP|. The azimuthal correlation is studied as a function of
both the trigger and associated particle \pt. The subtractions of the
combinatorial background and anisotropic flow, assuming Zero Yield At Minimum
(\zyam), are described. The away-side correlation is strongly modified, and the
modification varies with \phis, which is expected to be related to the
path-length that the away-side parton traverses. The pseudo-rapidity (\deta)
dependence of the near-side correlation, sensitive to long range \deta
correlations (the ridge), is also investigated. The ridge and jet-like
components of the near-side correlation are studied as a function of \phis.
The ridge appears to drop with increasing \phis while the jet-like component
remains approximately constant. ...Comment: 50 pages, 39 figures, 6 table
Studies of di-jet survival and surface emission bias in Au+Au collisions via angular correlations with respect to back-to-back leading hadrons
We report first results from an analysis based on a new multi-hadron
correlation technique, exploring jet-medium interactions and di-jet surface
emission bias at RHIC. Pairs of back-to-back high transverse momentum hadrons
are used for triggers to study associated hadron distributions. In contrast
with two- and three-particle correlations with a single trigger with similar
kinematic selections, the associated hadron distribution of both trigger sides
reveals no modification in either relative pseudo-rapidity or relative
azimuthal angle from d+Au to central Au+Au collisions. We determine associated
hadron yields and spectra as well as production rates for such correlated
back-to-back triggers to gain additional insights on medium properties.Comment: By the STAR Collaboration. 6 pages, 2 figure
Strangeness Enhancement in Cu+Cu and Au+Au Collisions at \sqrt{s_{NN}} = 200 GeV
We report new STAR measurements of mid-rapidity yields for the ,
, , , , ,
particles in Cu+Cu collisions at \sNN{200}, and mid-rapidity
yields for the , , particles in Au+Au at
\sNN{200}. We show that at a given number of participating nucleons, the
production of strange hadrons is higher in Cu+Cu collisions than in Au+Au
collisions at the same center-of-mass energy. We find that aspects of the
enhancement factors for all particles can be described by a parameterization
based on the fraction of participants that undergo multiple collisions
- …