Protective effect of Salvia miltiorrhiza and Carthamus tinctorius extract against lipopolysaccharide-induced liver injury

AIM:To investigate the hepatoprotective effects and mechanisms of an extract of Salvia miltiorrhiza and Carthamus tinctorius in vivo.METHODS:C57BL/6J mice were randomly assigned to five groups and intraperitoneally administered 0.9% saline,Salvia miltiorrhiza and Carthamus tinctorius extract [Danhong injection(DHI),0.75 and 3 g/kg mixed extract] or reduced glutathione for injection(RGI,300 mg/kg) for 30 min before exposure to lipopolysaccharide(LPS,16 mg/kg). After intraperitoneal LPS stimulation for 90 min or 6 h,the mice were sacrificed by ether anaesthesia,and serum and liver samples were collected. Histological analysis(H&E) and terminal deoxynucleotidyl transferase-mediated d UTP nick end-labelling(TUNEL) staining were performed. Alanine transferase(ALT),aspartate transaminase(AST),total bilirubin(TBil),glutathione-S-transferase(GST),malondialdehyde(MDA),tumour necrosis factor(TNF)-α,interleukin(IL)-6,and caspase-3 levels were measured. Bax,Bcl-2,P-IκBα,IκBα,P-NF-κB p65,and NF-κB p65 protein levels were determined by Western blot. TNF-α,IL-6,caspase-3,Bax and Bcl-2 m RNA expression was measured by real-time reverse transcription-polymerase chain reaction(RT-PCR).RESULTS:Hematoxylin-eosin staining and TUNEL results suggested that DHI(3 g/kg) treatment alleviated inflammatory and apoptotic(P < 0.01) injury in the liver of mice. DHI treatment dose-dependently blunted the abnormal changes in biochemical parameters such as ALT(72.53 ± 2.83 for 3 g/kg,P < 0.01),AST(76.97 ± 5.00 for 3 g/kg,P < 0.01),TBil(1.17 ± 0.10 for 3 g/kg,P < 0.01),MDA(0.81 ± 0.36 for 3 g/kg,P < 0.01),and GST(358.86 ± 12.09 for 3 g/kg,P < 0.01). Moreover,DHI(3 g/kg) remarkably decreased LPS-induced protein expression of TNF-α(340.55 ± 10.18 for 3 g/kg,P < 0.01),IL-6(261.34 ± 10.18 for 3 g/kg,P < 0.01),and enzyme activity of caspase-3(0.93 ± 0.029 for 3 g/kg,P < 0.01). The LPS-induced m RNA expression of TNF-α,IL-6 and caspase-3 was also decreased by DHI. Western blot analysis revealed that DHI antagonised LPS-stimulated decrease of Bcl-2 and increase of Bax protein expression. Furthermore,DHI inhibited LPS-induced IκBα and NF-κB p65 phosphorylation.CONCLUSION:DHI may be a multi-function protectant against acute hepatic injury in mice through its antiinflammatory,anti-oxidative and anti-apoptotic activities.

Spectral classification of stars based on LAMOST spectra

In this work, we select spectra of stars with high signal-to-noise ratio from LAMOST data and map their MK classes to the spectral features. The equivalent widths of prominent spectral lines, which play a similar role as multi-color photometry, form a clean stellar locus well ordered by MK classes. The advantage of the stellar locus in line indices is that it gives a natural and continuous classification of stars consistent with either broadly used MK classes or stellar astrophysical parameters. We also employ an SVM-based classification algorithm to assign MK classes to LAMOST stellar spectra. We find that the completenesses of the classifications are up to 90% for A and G type stars, but they are down to about 50% for OB and K type stars. About 40% of the OB and K type stars are mis-classified as A and G type stars,respectively. This is likely due to the difference in the spectral features between late B type and early A type stars or between late G and early K type stars being very weak. The relatively poor performance of the automatic MK classification with SVM suggests that the direct use of line indices to classify stars is likely a more preferable choice.

Preliminary study of a dispersed fringe type sensing system

Telescopes with large aspherical primary mirrors collect more light and are therefore sought after by astronomers. Instead of using a single large one-piece mirror, smaller segments can be assembled into a useable telescopic primary. Because the segments must fit together to create the effect of a single mirror, segmented optics present unique challenges to the fabrication and testing that are absent in monolithic optics. A dispersed fringe sensor (DFS) using a broadband point source is an efficient method for cophasing and is also highly automated and robust. Unlike the widely adopted ShackHartmann Wavefront sensor and curvature wavefront sensor with edge sensors for calibration of relative pistons, DFS can estimate the piston between segments by only using the spectrum formed by the transmissive grating’s dispersion, and therefore can replace the edge sensors, which are difficult to calibrate. We introduce the theory of the DFS and Dispersed Hartmann Sensor (DHS) for further utilization of the coarse phasing method of DFS. According to the theory, we bring out the preliminary system design of the cophasing experimental system based on DFS and DHS which is now established in our institute. Finally, a summary is reached.

19 low mass hypervelocity star candidates from the first data release of the LAMOST survey

Hypervelocity stars are believed to be ejected out from the Galactic center through dynamical interactions between(binary) stars and the central supermassive black hole(s). In this paper, we report 19 low mass F/G/K type hypervelocity star candidates from over one million stars found in the first data release of the LAMOST regular survey. We determine the unbound probability for each candidate using a MonteCarlo simulation by assuming a non-Gaussian proper-motion error distribution, and Gaussian heliocentric distance and radial velocity error distributions. The simulation results show that all the candidates have unbound possibilities over 50% as expected,and one of them may even exceed escape velocity with over 90% probability. In addition, we compare the metallicities of our candidates with the metallicity distribution functions of the Galactic bulge, disk, halo and globular clusters, and conclude that the Galactic bulge or disk is likely the birth place for our candidates.

Mapping the Milky Way with LAMOSTⅠ:method and overview

We present a statistical method to derive the stellar density profiles of the Milky Way from spectroscopic survey data,taking into account selection effects.We assume the selection function,which can be altered during observations and data reductions,of the spectroscopic survey is based on photometric colors and magnitude.Then the underlying selection function for a line-of-sight can be recovered well by comparing the distribution of the spectroscopic stars in a color-magnitude plane with that of the photometric dataset.Subsequently,the stellar density profile along a line-of-sight can be derived from the spectroscopically measured stellar density profile multiplied by the selection function.The method is validated using Galaxia mock data with two different selection functions.We demonstrate that the derived stellar density profiles reconstruct the true ones well not only for the full set of targets,but also for sub-populations selected from the full dataset.Finally,the method is applied to map the density profiles for the Galactic disk and halo,using the LAMOST RGB stars.The Galactic disk extends to about R=19 kpc,where the disk still contributes about 10% to the total stellar surface density.Beyond this radius,the disk smoothly transitions to the halo without any truncation,bending or breaking.Moreover,no over-density corresponding to the Monoceros ring is found in the Galactic anti-center direction.The disk shows moderate north–south asymmetry at radii larger than 12 kpc.On the other hand,the R–Z tomographic map directly shows that the stellar halo is substantially oblate within a Galactocentric radius of 20 kpc and gradually becomes nearly spherical beyond 30 kpc.

The first data release(DR1) of the LAMOST regular survey

The Large sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) general survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra of stars, galaxies and QSOs. Objects in both the pilot survey and the first year regular survey are included in the LAMOST DR1. The pilot survey started in October 2011 and ended in June 2012, and the data have been released to the public as the LAMOST Pilot Data Release in August 2012. The regular survey started in September 2012, and completed its first year of operation in June 2013. The LAMOST DR1 includes a total of 1202 plates containing 2 955 336 spectra, of which 1 790 879 spectra have observed signalto-noise ratio(SNR) ≥ 10. All data with SNR ≥ 2 are formally released as LAMOST DR1 under the LAMOST data policy. This data release contains a total of 2 204 696 spectra, of which 1 944 329 are stellar spectra, 12 082 are galaxy spectra and 5017 are quasars. The DR1 not only includes spectra, but also three stellar catalogs with measured parameters: late A,FGK-type stars with high quality spectra(1 061 918 entries), A-type stars(100 073 entries), and M-type stars(121 522 entries). This paper introduces the survey design, the observational and instrumental limitations, data reduction and analysis, and some caveats. A description of the FITS structure of spectral files and parameter catalogs is also provided.

A search for Mg-poor stars using LAMOST survey data

Most Galactic metal-poor stars exhibit enhanced α-abundances(e.g.[Mg/Fe] ～ +0.4) according to previous studies of stellar chemical compositions.However, a handful of metal-poor stars with large deficiencies in Mg(e.g. [Mg/Fe]～-0.2) show severe departures from this α-enhancement trend. The sub-solar[Mg/Fe] ratios of these anomalous stars indicate that they possess different chemical enrichment histories than the majority of Galactic metal-poor stars. In previous work,we presented a method to select Mg-poor metal-poor stars from low-resolution SDSS spectra based on a spectral matching technique. In this paper, a similar method is applied to low-resolution(R ～ 1800) LAMOST spectra. Stellar [Mg/Fe] abundances are determined by using stellar parameters delivered by the LAMOST Data Release2 catalog. From a sample of ～ 60 000 stars with atmospheric parameters in the range Teff = [5500, 6500] K and [Fe/H] = [-2.4, +0.5], we select 15 candidate Mg-poor metal-poor stars.

On the metallicity gradients of the Galactic disk as revealed by LSS-GAC red clump stars

Using a sample of over 70 000 red clump(RC) stars with 5%–10% distance accuracy selected from the LAMOST Spectroscopic Survey of the Galactic Anti-center(LSS-GAC), we study the radial and vertical gradients of the Galactic disk(s) mainly in the anti-center direction, covering a significant volume of the disk in the range of projected Galactocentric radius 7 ≤ RGC ≤ 14 kpc and height from the Galactic midplane 0 ≤ |Z | ≤ 3 kpc. Our analysis shows that both the radial and vertical metallicity gradients are negative across much of the volume of the disk that is probed, and they exhibit significant spatial variations. Near the solar circle(7 ≤ RGC ≤ 11.5 kpc), the radial gradient has a moderately steep, negative slope of-0.08 dex kpc-1near the midplane(|Z | < 0.1 kpc), and the slope flattens with increasing |Z |. In the outer disk(11.5 < RGC ≤ 14 kpc), the radial gradients have an essentially constant, much less steep slope of-0.01 dex kpc-1at all heights above the plane, suggesting that the outer disk may have experienced an evolutionary path different from that of the inner disk. The vertical gradients are found to flatten largely with increasing RGC. However, the vertical gradient of the lower disk(0 ≤ |Z | ≤ 1 kpc)is found to flatten with RGC quicker than that of the upper disk(1 < |Z | ≤ 3 kpc).Our results should provide strong constraints on the theory of disk formation and evolution, as well as the underlying physical processes that shape the disk(e.g. gas flows,radial migration, and internal and external perturbations).

Galactic disk bulk motions as revealed by the LSS-GAC DR2

We report a detailed investigation of the bulk motions of the nearby Galactic stellar disk, based on three samples selected from the LSS-GAC DR2: a global sample containing 0.57 million FGK dwarfs out to ～2 kpc, a local subset of the global sample consisting of ～5400 stars within 150 pc, and an anti-center sample containing ～4400AFGK dwarfs and red clump stars within windows a few degrees wide centered on the Galactic Anti-center. The global sample is used to construct a three-dimensional map of bulk motions of the Galactic disk from the solar vicinity out to ～2 kpc with a spatial resolution of ～250 pc. Typical values of the radial and vertical components of bulk motion range from-15 km s-1to 15 km s-1; in contrast, the lag behind the circular motion dominates the azimuthal component by up to ～15 km s-1. The map reveals spatially coherent, kpc-scale stellar flows in the disk, with typical velocities of a few tens of km s-1. Bending- and breathing-mode perturbations are clearly visible,and vary smoothly across the disk plane. Our data also reveal higher-order perturbations, such as breaks and ripples, in the profiles of vertical motion versus height. From the local sample, we find that stars from different populations exhibit very different patterns of bulk motion. Finally, the anti-center sample reveals a number of peaks in stellar number density in the line-of-sight velocity versus distance distribution, with the nearer ones apparently related to the known moving groups. The "velocity bifurcation" reported by Liu et al. at Galactocentric radii 10–11 kpc is confirmed. However,just beyond this distance, our data also reveal a new triple-peaked structure.

A comparison of stellar atmospheric parameters from the LAMOST and APOGEE datasets

We have compared stellar parameters, including temperature, gravity and metallicity, for common stars in the LAMOST DR2 and SDSS DR12/APOGEE datasets. It is found that the LAMOST dataset provides a more well-defined red clump feature than the APOGEE dataset in the Teff versus log g diagram. With this advantage, we have separated red clump stars from red giant stars, and attempt to establish calibrations between the two datasets for the two groups of stars. The results show that there is a good consistency in temperature with a calibration close to the one-to-one line, and we can establish a satisfactory metallicity calibration of[Fe/H]APOGEE= 1.18[Fe/H]LAMOST + 0.11 with a scatter of ～ 0.08 dex for both the red clump and red giant branch samples. For gravity, there is no correlation for red clump stars between the two datasets, and scatters around the calibrations of red giant stars are substantial. We found two main sources of scatter in log g for red giant stars. One is a group of stars with 0.00253 × Teff- 8.67 < log g < 2.6 located in the forbidden region, and the other is the contaminated red clump stars, which could be picked out from the unmatched region where stellar metallicity is not consistent with position in the Teff versus log g diagram. After excluding stars in these two regions,we have established two calibrations for red giant stars, log g APOGEE = 0.000615 ×Teff,LAMOST+ 0.697 × log g LAMOST- 2.208(σ = 0.150) for [Fe/H] >-1 and log gAPOGEE= 0.000874×Teff,LAMOST+0.588×log g LAMOST-3.117(σ = 0.167)for [Fe/H] <-1. The calibrations are valid for stars with Teff = 3800- 5400 K and log g = 0- 3.8 dex, and are useful in work aiming to combine the LAMOST and APOGEE datasets in a future study. In addition, we find that an SVM method based on asteroseismic log g is a good way to greatly improve the accuracy of gravity for these two regions, at least in the LAMOST dataset.

Radio stars observed in the LAMOST spectral survey

Radio stars have attracted astronomers' attention for several decades. To better understand the physics behind stellar radio emissions, it is important to study their optical behaviors. The LAMOST survey provides a large database for researching stellar spectroscopic properties of radio stars. In this work, we concentrate on their spectroscopic properties and infer physical properties from their spectra,such as stellar activity and variability. We mined big data from the LAMOST spectral survey Data Release 2(DR2), published on 2016 June 30, by cross-matching them with radio stars from FIRST and other surveys. We obtained 783 good stellar spectra with high signal to noise ratio for 659 stars. The criteria for selection were positional coincidence within 1.5′′and LAMOST objects classified as stars.We calculated the equivalent widths(EWs) of the Ca II H&K, Hδ, Hγ, Hβ, Hα and Ca II IRT lines by integrating the line profiles. Using the EWs of the Hα line, we detected 147 active stellar spectra of 89 objects having emissions above the Hα continuum. There were also 36 objects with repeated spectra,28 of which showed chromospheric activity variability. Furthermore, we found 14 radio stars emitting noticeably in the Ca II IRT lines. The low value of the EW8542/EW8498 ratio for these 14 radio stars possibly alludes to chromospheric plage regions.

A sample of galaxy pairs identified from the LAMOST spectral survey and the Sloan Digital Sky Survey

A small fraction(< 10%) of the SDSS main galaxy(MG) sample has not been targeted with spectroscopy due to the effect of fiber collisions. These galaxies have been compiled into the input catalog of the LAMOST Extra GAlactic Surveys and named the complementary galaxy sample. In this paper, we introduce this project and status of the spectroscopies associated with the complementary galaxies in the first two years of the LAMOST spectral survey(till Sep. of 2014). Moreover, we present a sample of 1102 galaxy pairs identified from the LAMOST complementary galaxies and SDSS MGs, which are defined as two members that have a projected distance smaller than 100 h_(70)^(-1)kpc and a recessional velocity difference smaller than 500 km s^(-1). Compared with galaxy pairs that are only selected from SDSS, the LAMOSTSDSS pairs have the advantages of not being biased toward large separations and therefore act as a useful supplement in statistical studies of galaxy interaction and galaxy merging.

On the LSP3 estimates of surface gravity for LAMOST-Kepler stars with asteroseismic measurements

Asteroseismology allows for deriving precise values of the surface gravity of stars. The accurate asteroseismic determinations now available for the large number of stars in the Kepler fields can be used to check and calibrate surface gravities that are currently being obtained spectroscopically for a huge number of stars targeted by large-scale spectroscopic surveys, such as the on-going Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) Galactic survey. The LAMOST spectral surveys have obtained a large number of stellar spectra in the Kepler fields. Stellar atmospheric parameters of those stars have been determined with the LAMOST Stellar Parameter Pipeline at Peking University(LSP3), by template matching with the MILES empirical spectral library. In the current work, we compare surface gravities yielded by LSP3 with those of two asteroseismic samples — the largest Kepler asteroseismic sample and the most accurate Kepler asteroseismic sample. We find that LSP3 surface gravities are in good agreement with asteroseismic values of Hekker et al., with a dispersion of ~0.2 dex. Except for a few cases, asteroseismic surface gravities of Huber et al. and LSP3 spectroscopic values agree for a wide range of surface gravities.However, some patterns in the differences can be identified upon close inspection. Potential ways to further improve the LSP3 spectroscopic estimation of stellar atmospheric parameters in the near future are briefly discussed. The effects of effective temperature and metallicity on asteroseismic determinations of surface gravities for giant stars are also discussed.

Data release of the LAMOST pilot survey

This paper describes the data release of the LAMOST pilot survey, which includes data reduction, calibration, spectral analysis, data products and data access. The accuracy of the released data and the information about the FITS headers of spectra are also introduced. The released data set includes 319 000 spectra and a catalog of these objects.

The 30-Day Oral Administration Studies of Liposoluble Tea Polyphenols in Rats

Tea polyphenols is a natural antioxidant with a variety of biological activity.However,the weak liposolubility and low bioavailability limit their application.As a result,structural modification of tea polyphenols comes into being.The prepared liposoluble tea polyphenols was suggested as a good candidate antioxidant for edible-oil and fats products.But,safety studies on liposoluble tea polyphenols are limited.The objective of the present study was conducted to synthesize liposoluble tea polyphenols and evaluate its toxicity in Sprague-Dawley rats on oral administration at dietary levels of 1,2 and 4% for 30 days.There were no adverse effects on general condition,growth,food intake,feed conversion efficiency,haematology parameters,clinical chemistry values and organ weights.High-dose males exhibited a higher haemoglobin concentration and a lower alanine aminotransferase levels,and high-dose females showed a lower albumin and globulin levels.These slight changes were considered of no toxicological significance.Necropsy and histopathology findings revealed no treatment-related changes in any of the organs.Thus,the results allowed us to conclude that the liposoluble tea polyphenols properly utilized in the oral administration could be devoid of any toxic risk.

The first symbiotic stars from the LAMOST survey

Symbiotic stars are interacting binary systems with the longest orbital periods. They are typically formed by a white dwarf and a red giant that are embedded in a nebula. These objects are natural astrophysical laboratories for studying the evolution of binaries. Current estimates of the population of symbiotic stars in the Milky Way vary from 3000 up to 400 000. However, a current census has found less than 300. The Large sky Area Multi-Object fiber Spectroscopic Telescope(LAMOST) survey can obtain hundreds of thousands of stellar spectra per year, providing a good opportunity to search for new symbiotic stars. We detect four such binaries among 4 147 802 spectra released by LAMOST, of which two are new identifications. The first is LAMOST J12280490–014825.7, considered to be an S-type halo symbiotic star. The second is LAMOST J202629.80+423652.0, a D-type symbiotic star.

M Dwarf catalog of LAMOST general survey data release one

We present a spectroscopic catalog of 93 619 M dwarfs from the first data release of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST)general survey. During sample selection, M giant contamination was eliminated using2 MASS photometry and Ca H/TiO molecular indices. For each spectrum, the spectral subtype and values are provided including radial velocity, Hα equivalent width, a series of prominent molecular band indices, and the metal–sensitive parameter ζ, as well as distances and the space motions for high S/N objects. In addition, Hα emission lines are measured to examine the magnetic activity properties of M dwarfs and 7179 active ones are found. In particular, a subsample with significant variation in magnetic activity is revealed through observations from different epochs. Finally, statistical analysis for this sample is performed, including the metallicity classification, the distribution of molecular band indices and their errors.

The metallicity of K giant stars along the Sagittarius streams

The Large Sky-Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) Data Release3 provided 341 691 K giant stars with stellar parameters. Based on the models of Law & Majewski, we identified 252 K giant stars in the leading stream associated with the Sagittarius(Sgr) dwarf galaxy. We obtained 132 K giant stars belonging to the trailing arm of Sgr using the model of Belokurov et al. We studied the metallicity distribution of member stars along the streams and found a flat gradient in the first wrap of the leading stream, –(0.88±0.3) × 10^(-3)dex/(~?) in the second wrap of the leading stream and–(1.2±0.3) × 10^(-3)dex/(~?) in the first wrap of the trailing stream. Moreover, we obtained a combined metallicity gradient with our sample and data from the literature. We also analyzed the properties of an overdensity, which is located in the leading stream of the Sgr.

A catalog of early-type emission-line stars and Hα line profiles from LAMOST DR2

We present a catalog including 11 204 spectra of 10 436 early-type emission-line stars from LAMOST DR2, among which 9752 early-type emission-line spectra are newly discovered. For these earlytype emission-line stars, we discuss the morphological and physical properties of their low-resolution spectra. In this spectral sample, the Hα emission profiles display a wide variety of shapes. Based on the Hα line profiles, these spectra are categorized into five distinct classes: single-peak emission, single-peak emission in absorption, double-peak emission, double-peak emission in absorption, and P-Cygni profiles. To better understand what causes the Hα line profiles, we divide these objects into four types from the perspective of physical classification, which include classical Be stars, Herbig Ae/Be stars, close binaries and spectra contaminated by H II regions. The majority of Herbig Ae/Be stars and classical Be stars are identified and separated using a(H-K, K-W1) color-color diagram. We also discuss 31 binary systems that are listed in the SIMBAD on-line catalog and identify 3600 spectra contaminated by H II regions after cross-matching with positions in the Dubout-Crillon catalog. A statistical analysis of line profiles versus classifications is then conducted in order to understand the distribution of Hα profiles for each type in our sample. Finally, we also provide a table of 172 spectra with Fe II emission lines and roughly calculate stellar wind velocities for seven spectra with P-Cygni profiles.

The LAMOST spectroscopic survey of globular clusters in M31and M33.I.catalog and new identifications

We present a catalog of 908 objects observed with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) in fields in the vicinity of M31 and M33, targeted as globular clusters(GCs) and candidates. The targets include known GCs and candidates selected from the literature, as well as new candidates selected from the Sloan Digital Sky Survey(SDSS). Analysis shows that 356 of them are likely GCs with various confidence levels, while the remaining ones turn out to be background galaxies and quasars, stars and H II regions in M31 or foreground Galactic stars. The 356 likely GCs include 298 bona fide GCs and 26 candidates known in the literature. Three candidates, selected from the Revised Bologna Catalog of M31 GCs and candidates(RBC) and one possible cluster from Johnson et al., are confirmed to be bona fide clusters. We search for new GCs in the halo of the M31 among the new candidates selected from the SDSS photometry. Based on radial velocities yielded by LAMOST spectra and visual examination of the SDSS images, we find 28 objects, 5bona fide and 23 likely GCs. Among the five bona fide GCs, three have been recently discovered independently by others, and the remaining 25 are our new identifications,including two bona fide ones. The newly identified objects fall at projected distances ranging from 13 to 265 kpc from M31. Of the two newly discovered bona fide GCs,one is located near M33, probably a GC belonging to M33. The other bona fide GC falls on the Giant Stream with a projected distance of 78 kpc from M31. Of the 23 newly identified likely GCs, one has a projected distance of about 265 kpc from M31 and could be an intergalactic cluster.