LAMOST medium-resolution spectroscopic survey of binarity and exotic star(LAMOST-MRS-B):Observation strategy and target selection

LAMOST-MRS-B is one of the sub-surveys of LAMOST medium-resolution(R~7500)spectroscopic survey.It aims at studying the statistical properties(e.g.,binary fraction,orbital period distribution,mass ratio distribution)of binary stars and exotic stars.We intend to observe about 30000 stars(10 mag≤G<14.5 mag)with at least 10 visits in five years.We first planned to observe 25 plates around the galactic plane in 2018.Then the plates were reduced to 12 in 2019 because of the limitation of observation.At the same time,two new plates located at the high galactic latitude were added to explore binary properties influenced by the different environments.In this survey project,we set the identified exotic and low-metallicity stars with the highest observation priorities.For the rest of the selected stars,we gave the higher priority to the relatively brighter stars in order to obtain high quality spectra as many as possible.Spectra of49129 stars have been obtained in LAMOST-MRS-B field and released in DR8,of which 28828 and 3375 stars have been visited more than twice and ten times with SNR≥10,respectively.Most of the sources are B-,A-,and F-type stars with-0.6<[Fe/H]<0.4 dex.We also obtain 347 identified variable and exotic stars and about 250 stars with[Fe/H]<-1 dex.We measure radial velocities(RVs)by using 892233 spectra of the stars.The uncertainties of RV achieve about 1 km·s^(-1)and 10 km·s^(-1)for 95%of late-and early-type stars,respectively.The datasets presented in this paper are available at http://www.doi.org/10.57760/sciencedb.j00113.00035.

不同控制水平哮喘患儿血清25(OH)D3、CC16水平和FeNO的变化及临床意义

目的探讨不同控制水平哮喘患儿血清25-羟维生素D3[25(OH)D3]、Clara细胞分泌蛋白16(CC16)水平和呼出气一氧化氮(FeNO)的临床意义。方法选取郑州大学附属儿童医院106例哮喘患儿为研究对象,依据哮喘控制水平分级标准分为良好控制组、部分控制组及未控制组。选取同期该院50例健康体检儿童为对照组。采用酶联免疫吸附试验(ELISA)检测各组儿童血清25(OH)D3、CC16、白细胞介素-4(IL-4)、血管内皮生长因子(VEGF)水平,并行FeNO测定,运用受试者工作特征(ROC)曲线评价血清25(OH)D3、CC16、IL-4、VEGF及FeNO对哮喘未控制的诊断价值。结果良好控制组、部分控制组及未控制组患儿血清25(OH)D3、CC16水平低于对照组(P<0.05),未控制组低于部分控制组及良好控制组(P<0.05);良好控制组、部分控制组及未控制组患儿血清IL-4、VEGF水平和FeNO值高于对照组(P<0.05),未控制组高于部分控制组及良好控制组(P<0.05);血清25(OH)D3与CC16呈正相关(P<0.05),与IL-4、VEGF及FeNO呈负相关(P<0.05);ROC曲线结果显示血清25(OH)D3、CC16诊断哮喘未控制的曲线下面积分别为0.902[(95%CI:0.809,0.966),P=0.001]和0.764[(95%CI:0.621,0.907),P=0.003],截断值分别为18.523 ng/ml、10.741μg/L,特异性分别为83.6%和76.4%,敏感性分别为89.2%和82.7%。结论哮喘患儿血清25(OH)D3、CC16与哮喘控制水平相关,检测哮喘患儿血清25(OH)D3及CC16水平,同时动态监测FeNO,对评估哮喘控制水平及调整治疗方案具有指导意义。

Effects and mechanism of miR-214 on hepatocellular carcinoma

Objective:To explore the role of miR-214 in the progression of hepatocellular carcinoma（HCC） and its inhibitory mechanisms in depressing the signaling pathway of j3-catenin.this study was conducted.Methods:We ectopically expressed miR-214 in HepG2 cells to obtain cell lines Lv-miR-214-HepG2 and their control Lv-control-HepG2.Differences between the two cell lines were compared in cell growth,proliferation,colony forming ability and cell cycles.RT-PCR method was applied for the quantification of β-catenin mRNA expression.Western-blot method was applied for the determination of the protein level of β-catenin and their downstream targets（ie.Cyclin D1,c-Myc and TCF-1）.The effect of miR-214 on cells was further explored through RNA interference and restoring miR-214 expression.Results:In comparison with negative（Lv-control-HepG2） and blank（HepG2） control,a significant inhibition of cell growth and proliferation caused by miR-214 was observed after 4872h of cell culture experiments（P【0.05）.The miR-214 treatment resulted in a colony forming efficiency of（23.28±3.26）%,which was significantly lower than that of negative control[（51.31±3.97）%]（P【0.05）.According to FCM results,the experimental group,compared with control,showed a higher proportion of cells in G0/G1 phase[（70.32±3.12）%]but a lower proportion in S phase[（18.42±2.90）%]（P【0.05）.The MTT assay demonstrated a significant inhibition of the proliferation and β-catenin expression of HCC cells compared with control（P【0.05）.while no significant difference was observed after HCC cells being transfected withβ-catenin overexpression plasmid（P】0.05）.By comparing to the RT-PCR and Western-blot results of control,the miR-214 treatment led to a slightly decrease in the β-catenin mRNA expression（P】0.05）.but an extremely inhibition in the protein level of β-catenin and its downstream targets Cyclin Dl,c-Myc.and TCF-1（P【0.05）.Conclusions:miR-214 functions as a suppressor during the progression of HCC,and its inhibitory role was achieved by downregulating β-catenin signaling pathway.

Treatment of Scrapie Pathogen 263K With Tetracycline Partially Abolishes Protease-resistant Activity in vitro and Reduces Infectivity in vivo

Objective To study the possible effect of tetracycline on protease-resistant activity in vitro and infectivity in vivo of a scrapie strain 263K. Methods Scrapie pathogens were incubated with tetracycline at different concentrations for various periods of time and protease-resistant PrP signals were evaluated with proteinase K-treatment and Western blots. The preparations treated with tetracycline were intracerebrally inoculated into golden hamsters and typical TSE manifestations were noted. PrP^5c in brain tissues of the infected animals was detected by PrP specific Western blot assays. Results Protease-resistant PrP was significantly reduced in or removed from the preparations treated with tetracycline in a dose-dependant manner. Compared with the control group after incubated for 53.75±0.50 days, the preparations treated with 5 mmol/L and 20 mmol/L tetracycline prolonged the incubation time of 61.5±1.73 and 59.5±0.58 days （P〈0.05）. Conclusion Treatment of scrapie pathogen 263K with tetracycline reduces or removes its protease-resistant activity in vitro.

Effects of gene silencing of CypB on gastric cancer cells

Objective:To determine the effect of gene silencing of cyclophilin B(CypB)on growth and proliferation of gastric cancer cells.Methods:CypB siRNA lentivirus(LV-CypB-si)and control lentivirus(LV-si-con)were produced.CypB expression in gastric cancer cell lines was detected by Western blot.BGC823 and SGC7901 cells were chosen to be infected with LV-sicon and LV-CypB-si,and stable transfectants were isolated.The cell groups transfected with LV-CypB-siRNA,LV-siRNA-con and transfected no carrier were served as the experimental group,the implicit control group and the blank control group respectively.MTT and colony formation assays were used to examine the effect of CypB on the cell growth and proliferation in vitro.Cell cycle was analyzed with flow cytometry.The expression of VEGFR of BGC823-si and SGC7901-si was detected by Western blot.Results:Gene silencing of CypB can inhibit gastric cancer cell growth,proliferation,cell cycle progress and tumorigenesis.CypB expression level was obviously higher in SGC7901 and BGC823 than MKN28 and GES.These two cell lines were infected with LV-si-con and LV-CypB-si respectively.MTT and cloney formation assays showed a significantly decreased rate of cell proliferation from the forth day or the fifth day in cells transfected with LV-CypB-si(P<0.05).Down-regulation of CypB resulted in slightly decreased percentage of S phase and increased percentage of G_1(P<0.05).These findings indicated that CypB could promote the G_1-S transition of gastric cancer cell.In addition,the expression of VEGF of BGC823 and SGC7901 transfected with CypB siRNA was reduced in comparison with the implicit control group and the blank control group.Conclusions:Gene silencing of CypB decreases gastric cancer cells proliferation and in vivo tumorigenesis.These findings indiccate CypB could be a potential biomarker and therapeutic target for gastric cancer.

Understanding the X-ray spectrum of anomalous X-ray pulsars and soft gamma-ray repeaters

Hard X-rays above 10 keV are detected from several anomalous X-ray pul- sars （AXPs） and soft gamma-ray repeaters （SGRs）, and different models have been proposed to explain the physical origin within the frame of either a magnetar model or a fallback disk system. Using data from Suzaku and INTEGRAL, we study the soft and hard X-ray spectra of four AXPs/SGRs： 1RXS J 170849-400910, 1E 1547.0- 5408, SGR 1806-20 and SGR 0501＋4516. It is found that the spectra could be well reproduced by the bulk-motion Comptonization （BMC） process as was first suggested by Triimper et al., showing that the accretion scenario could be compatible with X- ray emission from AXPs/SGRs. Simulated results from the Hard X-ray Modulation Telescope using the BMC model show that the spectra would have discrepancies from the power-law, especially the cutoff at -200 keV. Thus future observations will allow researchers to distinguish different models of the hard X-ray emission and will help us understand the nature of AXPs/SGRs.

Binary fraction of O and B-type stars from LAMOST data

Abstract:Binary stars play an important role in the evolution of stellar populations.The intrinsic binary fraction(fbin)of O and B-type(OB)stars in LAMOST DR5 was investigated in this work.We employed a cross-correlation approach to estimate relative radial velocities for each of the stellar spectra.The algorithm described by Sana et al.(2013)was implemented and several simulations were made to assess the performance of the approach.The binary fraction of the OB stars is estimated through comparing the unidistribution between observations and simulations with the Kolmogorov-Smirnov tests.Simulations show that it is reliable for stars most of whom have six,seven and eight repeated observations.The uncertainty of orbital parameters of binarity becomes larger when observational frequencies decrease.By adopting the fixed power exponents ofπ=-0.45 andκ=-1 for period and mass ratio distributions,respectively,we obtain that fbin=0.4-0.06+0.05 for the samples with more than three observations.When we consider the full samples with at least two observations,the binary fraction turns out to be 0.37-0.03+0.03.These two results are consistent with each other in 1σ.

Hard X-ray emission cutoff in the anomalous X-ray pulsar 4U 0142+61 detected by INTEGRAL

The anomalous X-ray pulsar 4U 0142＋61 has been studied with obser- vations from INTEGRAL. The hard X-ray spectrum in the range 18-500 keV for 4U 0142＋61 was derived using nearly nine years of INTEGRAL/IBIS data. We ob- tained the average hard X-ray spectrum of 4U 0142＋61 with all available data. The spectrum of 4U 0142＋61 can be fitted with a power law that includes an exponen- tial high energy cutoff. This average spectrum is well fitted by a power law with r ,~ 0.51 ± 0.11 plus a cutoff energy at 128.6 ± 17.2 keV. The hard X-ray flux of the source from 20-150 keV showed no significant variations （within 20%） from 2003- 2011. The spectral profiles have some variability over the nine years such that the photon index varies from 0.3-1.5 and the cutoff energies from 110-250 keV. The de- tection of the high energy cutoff around 130 keV shows some constraints on the radia- tion mechanisms of magnetars and possibly probes the differences between magnetar and accretion models for this special class of neutron stars. Future HXMTobservations could provide stronger constraints on the hard X-ray spectral properties of this source and other magnetar candidates.

The influence of increasing temperatures on highland barley yields and on the maximum cultivation altitude on the Tibetan Plateau

Highland barley(Hordeum vulgare Linn.cv.nudum Hook.f.)is the principal cereal crop over the Tibetan Plateau(TP).The response of highland barely to climate change in the past decades,especially in terms of yields still remains uncertain.In this study,its responses to climate change were investigated using daily weather data and agriculture data during 1961–2018.The results showed that the annual mean air temperature over the TP increased at 0.33°C per decade during 1961–2018,and the rate of warming increased with altitude,reaching 0.41°C per decade at altitudes of 4500–4700 m.The growing degree days(GDDs)increased by 9.6%during 2011–2018 compared with the 1960s,whereas low temperature degree days(LDDs)decreased by 40.3%over the same period,indicating that the thermal conditions for highland barley cultivation have improved.A strong relationship was observed between the yield of highland barley and LDDs(−0.76,p<0.001)than GDDs(0.58,p<0.001)in Xizang,where sufficient irrigation water is available from the melting of snow cover or glaciers.In Sichuan,with abundant precipitation,significant correlations were noticed between county-level barley yield and GDDs and LDDs(0.60,p<0.001;−0.65,p<0.001).In Qinghai,the dry regions,county-level yields were influenced significantly by temperature and precipitation.These results indicated that climate warming was beneficial to highland barley yield in most region of the TP,mainly due to decreased LDDs.The potential altitude at which highland barley cultivation is feasible increased by approximately 280–484 m during 2016–2018,compared with 1981–1983.In Xizang,highland barley could be cultivated up to an altitude of 4507 m a.s.l.between 2016 and 2018,and it increased to 4179 m a.s.l.in Qinghai.These results could help local government to take actions to adapt to global warming and improve food security.

Effect of Solution Annealing Temperature on Pitting Behavior of Duplex Stainless Steel 2204 in Chloride Solutions

The effect of solution annealing temperature ranging from 950 to 1 200 ℃ on the microstructure and corrosion performance of duplex stainless steel （DSS） 2204 were investigated. The proportion of the ferrite phase increased while the austenite phase decreased and the ferrite stabilizing elements diluted in the ferrite phase with the increase of annealing temperature. The critical pitting temperature （CPT） of specimens annealed at 1000℃ was higher than those annealed at 950℃, whereas further increasing the annealing temperature to 1200℃ decreased the CPT. The pitting initiation sites were observed in the austenite phase, at the boundary of ferrite/austenite phase and inside the ferrite phase for specimens annealed at 950, 1000℃ and exceeding 1 100℃, respectively. The evolution trend of the CPT and the pit initiation site were analyzed by the pitting resistance equivalent number.

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000°C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS)2002 was investigated through the potentiostatic critical pitting temperature(CPT)tests and the Charpy impact tests.Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650°C concurrently.The CPT of LDSS 2002 specimen aged at 650°C decreased by 28°C,and the impact energy dropped from 69 to 29 J/cm2 compared with the solution-annealed sample.Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr2N and M23C6 along the ferrite–austenite grain boundaries.

Split Nano luciferase complementation for probing protein-protein interactions in plant cells

Deciphering protein-protein interactions(PPIs)is fundamental for understanding signal transduction pathways in plants.The split firefly luciferase(Fluc)complementation(SLC)assay has been widely used for analyzing PPIs.However,concern has risen about the bulky halves of Fluc interfering with the functions of their fusion partners.Nano luciferase(Nluc)is the smallest substitute for Fluc with improved stability and luminescence.Here,we developed a dual-use system enabling the detection of PPIs through the Nluc-based SLC and co-immunoprecipitation assays.This was realized by coexpression of two proteins under investigation in fusion with the HA-or FLAG-tagged Nluc halves,respectively.We validated the robustness of this system by reproducing multiple previously documented PPIs in protoplasts or Agrobacterium-transformed plants.We next applied this system to evaluate the homodimerization of Arabidopsis CERK1,a coreceptor of fungal elicitor chitin,and its heterodimerization with other homologs in the absence or presence of chitin.Moreover,split fragments of Nluc were fused to two cytosolic ends of Arabidopsis calcium channels CNGC2 and CNGC4 to help sense the allosteric change induced by the bacterial elicitor flg22.Collectively,these results demonstrate the usefulness of the Nluc-based SLC assay for probing constitutive or inducible PPIs and protein allostery in plant cells.

Detection of Epstein-Barr virus infection subtype in patients with multiple sclerosis by indirect immunofluorescence assay

Aim:The aim was to investigate the infectious conditions of Epstein-Barr virus(EBV)in patients with multiple sclerosis(MS).Methods:Cerebrospinal fluid(CSF)of 20 patients with MS and 20 with other neurological diseases(OND)were tested with indirect immunofluorescence for anti-EBV capsid antigen(EBV-CA)immunoglobulin G(IgG),IgG affinity for anti-EBV-CA,anti-EBV-CA immunoglobulin M(IgM),anti-EBV early antigen(EBV-EA)IgG and anti-EBV nuclear antigen(EBNA)IgG.According to the pattern of antibodies in CSF,infection rates of acute,chronic,primary,recurrent,and past infections were analyzed in the two groups of patients.Results:There were no significant differences in anti-EBV-CA,anti-EBC-EA,and anti-EBNA antigen IgG in CSF between MS and OND patients(P>0.05).The positive rate of low affinity for anti-EBV-CA IgG in MS patients was significantly higher than that for OND patients(75%vs.40%,P<0.05).Furthermore,significant differences in the positive rate of anti-EBV-CA IgM were found between MS and OND patients(70%vs.25%,P<0.05).Of the MS patients,75%were in an EBV acute infection state compared with 40%of OND patients(P<0.05).Conclusion:Acute infection of EBV closely correlates with the occurrence of MS.