1,446 research outputs found
Effect of Alisma plantago-aquatica Linn extract on hyperprolactinemia in rats
Purpose: To investigate the anti-hyperprolactinemia effect and mechanism of action of of Alisma plantago-aquatica Linn. extract (APLE) in rats.
Methods: The hyperprolactinemia (hyperPRL) model of rats was established by intraperitoneal (i.p.) metoclopramide (200 mg/kg daily) for 10 days. Sixty rats were divided into six groups (n = 10 each): normal group), hyperPRL control group, hyperPRL plus 0.6 mg/kg bromocriptine (as a positive control) group, and hyperPRL plus high (14.4 g/kg), medium (7.2 g/kg), or low (3.6 g/kg) dose of APLE. Bromocriptine or vehicle control was administered to the rats daily for 30 days, and the hypothalamus dopamine D2 receptor, protein kinase A (PKA), and cyclic adenosine monophosphate (cAMP) levels were investigated by Western blot.
Results: Compared with the normal rats, hypothalamus dopamine D2 receptor protein expression was significantly lower in hyperPRL rats (p < 0.01), but was changed significantly after 30-day doses (various) of APLE administration (3.6 g/kg, p < 0.05; 7.2 and 14.4 g/kg, p < 0.01). Compared with the control rats, hypothalamus PKA and cAMP levels were significantly higher in hyperPRL rats (p < 0.01). These increases in PKA and cAMP were significantly attenuated by 30-day of bromocriptine treatment or various doses of APLE (p < 0.01).
Conclusion: The anti-hyperPRL activity of APLE is confirmed from the findings of this study Thus, the plant can potentially be developed into a new anti-hyperprolactinemia drug
What can we learn about solar coronal mass ejections, coronal dimmings, and Extreme-Ultraviolet jets through spectroscopic observations?
We analyze several data sets obtained by Hinode/EIS and find various types of
flows during CMEs and EUV jet eruptions. CME-induced dimming regions are found
to be characterized by significant blueshift and enhanced line width by using a
single Gaussian fit. While a red-blue (RB) asymmetry analysis and a RB-guided
double Gaussian fit of the coronal line profiles indicate that these are likely
caused by the superposition of a strong background emission component and a
relatively weak (~10%) high-speed (~100 km s-1) upflow component. This finding
suggests that the outflow velocity in the dimming region is probably of the
order of 100 km s-1, not ~20 km s-1 as reported previously. Density and
temperature diagnostics suggest that dimming is primarily an effect of density
decrease rather than temperature change. The mass losses in dimming regions as
estimated from different methods are roughly consistent with each other and
they are 20%-60% of the masses of the associated CMEs. With the guide of RB
asymmetry analysis, we also find several temperature-dependent outflows (speed
increases with temperature) immediately outside the (deepest) dimming region.
In an erupted CME loop and an EUV jet, profiles of emission lines formed at
coronal and transition region temperatures are found to exhibit two
well-separated components, an almost stationary component accounting for the
background emission and a highly blueshifted (~200 km s-1) component
representing emission from the erupting material. The two components can easily
be decomposed through a double Gaussian fit and we can diagnose the electron
density, temperature and mass of the ejecta. Combining the speed of the
blueshifted component and the projected speed of the erupting material derived
from simultaneous imaging observations, we can calculate the real speed of the
ejecta.Comment: 20 figures. Ready for publication in ApJ. The quality of Figures 4,5
15 & 20 is greatly reduced as a result of the requirement of the size limit
of arXiv.org. High-quality version of these figures can be found in
http://download.hao.ucar.edu/pub/htian
A spectroscopic study of the blue stragglers in M67
Based on spectrophotometric observations from the Guillermo Haro Observatory
(Cananea, Mexico), a study of the spectral properties of the complete sample of
24 blue straggler stars (BSs) in the old Galactic open cluster M67 (NGC 2682)
is presented. All spectra, calibrated using spectral standards, were
recalibrated by means of photometric magnitudes in the
Beijing-Arizona-Taipei-Connecticut system, which includes fluxes in 11 bands
covering ~3500-10000 A. The set of parameters was obtained using two
complementary approaches that rely on a comparison of the spectra with (i) an
empirical sample of stars with well-established spectral types and (ii) a
theoretical grid of optical spectra computed at both low and high resolution.
The overall results indicate that the BSs in M67 span a wide range in Teff(~
5600 -12600 K) and surface gravities that are fully compatible with those
expected for main-sequence objects (log g = 3.5 -5.0 dex).Comment: 10 pages, 10 figures, published in MNRAS (2008, Volume 390, Issue 2,
pp. 665-674
Polarization-sensitive optical projection tomography for muscle fiber imaging
Optical projection tomography (OPT) is a tool used for three-dimensional imaging of millimeter-scale biological samples, with the advantage of exhibiting isotropic resolution typically in the micron range. OPT can be divided into two types: transmission OPT (tOPT) and emission OPT (eOPT). Compared with eOPT, tOPT discriminates different tissues based on their absorption coefficient, either intrinsic or after specific staining. However, it fails to distinguish muscle fibers whose absorption coefficients are similar to surrounding tissues. To circumvent this problem, in this article we demonstrate a polarization sensitive OPT system which improves the detection and 3D imaging of muscle fibers by using polarized light. We also developed image acquisition and processing protocols that, together with the system, enable the clear visualization of muscles. Experimental results show that the muscle fibers of diaphragm and stomach, difficult to be distinguished in regular tOPT, were clearly displayed in our system, proving its potential use. Moreover, polarization sensitive OPT was fused with tOPT to investigate the stomach tissue comprehensively. Future applications of polarization sensitive OPT could be imaging other fiberlike structures such as myocardium or other tissues presenting high optical anisotropy.This work is supported by the National Basic Research Program of China (973 Program) under Grant 2011CB707700, the National Natural Science Foundation of China under Grant No. 81227901, 61231004, 81501616, 81301346, 81527805 the Chinese Academy of Sciences Fellowship for Young Foreign Scientists under Grant No. 2010Y2GA03, 2013Y1GA0004, the Chinese Academy of Sciences Visiting Professorship for Senior
International Scientists under Grant No. 2012T1G0036, 2013T1G0013, the Instrument Developing Project of the Chinese Academy of Sciences under Grant No. YZ201502, YZ201457 and the Strategic Priority Research Program (B) of Chinese Academy of Sciences (XDB02060010). A. Arranz acknowledges support from the Marie Curie Intra-European Fellowship program IEF-2010-275137. J.R. acknowledges support from EC FP7 IMI project PREDICT-TB, the EC FP7 CIG grant HIGH-THROUGHPUT TOMO, and the Spanish MINECO project grant FIS2013-41802-R MESO-IMAGING
Modeling blue stragglers in young clusters
In this paper, a grid of the binary evolution models are calculated for the
study of blue straggler (BS) population in intermediate age (=7.85-8.95) star clusters. The BS formation via mass transfer and merging
is studied systematically using our models. Both Case A and B close binary
evolutionary tracks are calculated in a large range of parameters. The results
show that BSs formed via Case B are generally bluer and even more luminous than
those produced by Case A. Furthermore, the larger range in orbital separations
of Case B models provide a probability of producing more BSs than Case A. Based
on the grid of models, several Monte-Carlo simulations of BS populations in the
clusters in the age range are carried out. The results show that BSs formed via
different channels populate different areas in color magnitude diagram(CMD).
The locations of BSs in CMD for a number of clusters are compared to our
simulations as well. In order to investigate the influence of mass transfer
efficiency in the models and simulations, a set of models are also calculated
by implementing a constant mass transfer efficiency, =0.5 during Roche
lobe overflow (Case A binary evolution excluded). The result shows BSs can be
formed via mass transfer at any given age in both cases. However, the
distributions of the BS populations on CMD are different.Comment: 18 pages, 5 figures, 2 table
Two components of the coronal emission revealed by EUV spectroscopic observations
Recent spectroscopic observations have revealed the ubiquitous presence of
blueward asymmetries of emission lines formed in the solar corona and
transition region. These asymmetries are most prominent in loop footpoint
regions, where a clear correlation of the asymmetry with the Doppler shift and
line width determined from the single Gaussian fit is found. Such asymmetries
suggest at least two emission components: a primary component accounting for
the background emission and a secondary component associated with high-speed
upflows. The latter has been proposed to play a vital role in the coronal
heating process and there is no agreement on its properties. Here we slightly
modify the initially developed technique of Red-Blue (RB) asymmetry analysis
and apply it to both artificial spectra and spectra observed by the EUV Imaging
Spectrometer onboard Hinode, and demonstrate that the secondary component
usually contributes a few percent of the total emission, has a velocity ranging
from 50 to 150 km s-1 and a Gaussian width comparable to that of the primary
one in loop footpoint regions. The results of the RB asymmetry analysis are
then used to guide a double Gaussian fit and we find that the obtained
properties of the secondary component are generally consistent with those
obtained from the RB asymmetry analysis. Through a comparison of the location,
relative intensity, and velocity distribution of the blueward secondary
component with the properties of the upward propagating disturbances revealed
in simultaneous images from the Atmospheric Imaging Assembly onboard the Solar
Dynamics Observatory, we find a clear association of the secondary component
with the propagating disturbances.Comment: 19 figures, accepted by Ap
Targeting USP1-dependent KDM4A protein stability as a potential prostate cancer therapy
The histone demethylase lysine-specific demethylase 4A (KDM4A) is reported to be overexpressed and plays a vital in multiple cancers through controlling gene expression by epigenetic regulation of H3K9 or H3K36 methylation marks. However, the biological role and mechanism of KDM4A in prostate cancer (PC) remain unclear. Herein, we reported KDM4A expression was upregulation in phosphatase and tensin homolog knockout mouse prostate tissue. Depletion of KDM4A in PC cells inhibited their proliferation and survival in vivo and vitro. Further studies reveal that USP1 is a deubiquitinase that regulates KDM4A K48-linked deubiquitin and stability. Interestingly, we found c-Myc was a key downstream effector of the USP1-KDM4A/androgen receptor axis in driving PC cell proliferation. Notably, upregulation of KDM4A expression with high USP1 expression was observed in most prostate tumors and inhibition of USP1 promotes PC cells response to therapeutic agent enzalutamide. Our studies propose USP1 could be an anticancer therapeutic target in PC
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