Background:This study aimed to portray the atomic intelligence and prognostic implications of differentially expressed genes and their involvement in biological pathways in endometrial carcinoma,with a specific focus ...Background:This study aimed to portray the atomic intelligence and prognostic implications of differentially expressed genes and their involvement in biological pathways in endometrial carcinoma,with a specific focus on the impacts of exercise on cancer.Methods:We utilized a multi-faceted approach,including volcano plots,Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses,Venn diagrams,protein-protein interaction networks,Kaplan-Meier survival analysis,Gene Set Variety Analysis,and single-cell transcriptomic analysis.Furthermore,we profiled tumor mutational scenes,assessed the prognostic value of immune-related features,and conducted a comprehensive examination of genetic variations and their impact on tumor mutational burden across different cancer types.Multidimensional genomic interactions and methylation elements were also investigated.Using real-time quantitative PCR and immunofluorescence staining,the effects of B-cell lymphoma 2(BCL2)silencing on TNF-αand caspase-3 gene expression were evaluated.Results:Our study identified a noteworthy number of differentially expressed genes in endometrial carcinoma with potential links to athletic performance traits.BCL2 expression levels were found to be associated with survival outcomes,and its changeability across cancers was related to immune cell infiltration and immune checkpoint gene expression.Single-cell investigations uncovered cellular complexity within tumor microenvironments and critical biological pathways in BCL2-overexpressing cells.The expression flow and mutational effect of BCL2 in endometrial carcinoma were characterized,and the prognostic implications of immune-related features were assessed.Hereditary variations,including copy number variations and their relationship with gene expression and tumor mutational burden,were investigated.Multidimensional genomic transaction highlighted the essential role of regulatory genes in cancer pathogenesis.Silencing of the BCL2 gene significantly inhibited the proliferation of HEC-108 cells and promoted apoptosis,as evidenced by decreased TNF-αgene expression and increased caspase-3 gene expression.Immunofluorescence staining further confirmed these results.Conclusion:This study gives a point-by-point understanding of the atomic intelligence and prognostic implications in endometrial carcinoma and across various other cancers.BCL2’s role as a modulatory factor within the tumor-resistant environment and its potential impact on disease prognosis and response to immunotherapy were underscored.The multidimensional genomic analysis provides insights into the complex interaction between genetic and epigenetic variables in cancer,which may shed light on future therapeutic strategies.This study indicates that silencing the BCL2 gene can significantly inhibit tumor cell proliferation and promote apoptosis through the regulation of the TNF-αand caspase-3 pathways.展开更多
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 ...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.展开更多
Metal-deficient stars are regarded as fossils of the early generation of stars and therefore make crucial observational targets related to stellar astrophysics. They provide fundamental information and insights on pro...Metal-deficient stars are regarded as fossils of the early generation of stars and therefore make crucial observational targets related to stellar astrophysics. They provide fundamental information and insights on properties of the very early stage of the chemical history of the Galaxy and have been investigated for decades. The unique design of the Guoshoujing Telescope (LAMOST), such as its large field and multi-object observational capability, enables it to be an excellent tool for searching for these metal-poor stars in the Milky Way. This work reports the result of test observations which search for metal-poor stars with LAMOST, during which nine candidate metal-poor stars with [Fe/H] ≤ - 1.0 were newly detected based on the low-resolution spectroscopic observations of the LAMOST commissioning data. The sample of stars demonstrates the efficiency of selecting from the input catalog, as well as the ability of LAMOST to enlarge the sample of metal-poor stars in the Milky Way. Furthermore, the sample of stars could be used for future calibrations of the LAMOST stellar pa- rameter pipeline.展开更多
A number of spectroscopic surveys have been carried out or are planned to study the origin of the Milky Way. Their exploitation requires reliable automated methods and softwares to measure the fundamental parameters o...A number of spectroscopic surveys have been carried out or are planned to study the origin of the Milky Way. Their exploitation requires reliable automated methods and softwares to measure the fundamental parameters of the stars. Adopting the ULySS package, we have tested the effect of different resolutions and signal-to- noise ratios (SNR) on the measurement of the stellar atmospheric parameters (effective temperature Teff, surface gravity log g, and metaUicity [Fe/H]). We show that ULySS is reliable for determining these parameters with medium-resolution spectra (R ~2000). Then, we applied the method to measure the parameters of 771 stars selected in the commissioning database of the Guoshoujing Telescope (LAMOST). The results were compared with the SDSS/SEGUE Stellar Parameter Pipeline (SSPP), and we derived precisions of 167 K, 0.34dex, and 0.16dex for Teff, logg and [Fe/H] respectively. Furthermore, 120 of these stars are selected to construct the primary stellar spectral template library (Version 1.0) of LAMOST, and will be deployed as basic ingredients for the LAMOST automated parametrization pipeline.展开更多
Strongly Mg-enhanced stars with [Mg/Fe] 〉 1.0 show peculiar abundance patterns and hence are of great interest for our understanding of stellar formation and chemical evolution of the Galaxy. A systematic search for ...Strongly Mg-enhanced stars with [Mg/Fe] 〉 1.0 show peculiar abundance patterns and hence are of great interest for our understanding of stellar formation and chemical evolution of the Galaxy. A systematic search for strongly Mg-enhanced stars based on low-resolution (R≈2000) spectra from the Sloan Digital Sky Survey (SDSS) is carried out by finding the synthetic spectrum that best matches the observed one in the region of Mg I b lines around λ5170 ,A via a profile matching method. The advantage of our method is that fitting parameters are refined by reproducing the [Mg/Fe] ratios of 47 stars from the very precise high-resolution spectroscopic (HRS) analysis by Nissen & Schuster; and these parameters are crucial to the precision and validity of the derived Mg abundances. As a further check of our method, Mg abun- dances are estimated with our method for member stars in four Galactic globular clus- ters (M92, M 13, M3, M71) which cover the same metallicity range as our sample, and the results are in good agreement with those of HRS analysis in the literature. The val- idation of our method is also demonstrated by the agreement of [Mg/Fe] between our values and those of HRS analysis by Aoki et al. Finally, 33 candidates of strongly Mg- enhanced stars with [Mg/Fe]〉 1.0 are selected from 14 850 F and G stars. Follow-up observations will be carried out on these candidates with high-resolution spectroscopy by large telescopes in the near future, so as to check our selection procedure and to perform a precise and detailed abundance analysis and to explore the origins of these stars.展开更多
The abundance patterns of r-process-enhanced stars contain key information required to constrain the astrophysical site(s)of r-process nucleosynthesis,and to deepen our understanding of the chemical evolution of our G...The abundance patterns of r-process-enhanced stars contain key information required to constrain the astrophysical site(s)of r-process nucleosynthesis,and to deepen our understanding of the chemical evolution of our Galaxy.To expand the sample of known r-process-enhanced stars,we have developed a method to search for candidates in the LAMOST medium-resolution(R7500)spectroscopic survey by matching the observed spectra to synthetic templates around the EuⅡline at 6645.1 A.We obtain a sample of 13 metal-poor(-2.35<[Fe/H]<-0.91)candidates from 12209 unique stars with 32774 mediumresolution spectra.These candidates will be further studied by high-resolution follow-up observations in the near future.We describe some extensions of this effort to include larger samples of stars,in particular at lower metallicity,using the strength of the BaⅡline at 6496.9 A.展开更多
We report the discovery of an extremely metal-poor(EMP) giant,LAMOST J110901.22+075441.8, which exhibits a large excess of r-process elements with [Eu/Fe] ~ +1.16. The star is one of the newly discovered EMP star...We report the discovery of an extremely metal-poor(EMP) giant,LAMOST J110901.22+075441.8, which exhibits a large excess of r-process elements with [Eu/Fe] ~ +1.16. The star is one of the newly discovered EMP stars identified from the LAMOST low-resolution spectroscopic survey and a highresolution follow-up observation with the Subaru Telescope. Stellar parameters and elemental abundances have been determined from the Subaru spectrum. Accurate abundances for a total of 23 elements including 11 neutron-capture elements from Sr through Dy have been derived for LAMOST J110901.22+075441.8. The abundance pattern of LAMOST J110901.22+075441.8 in the range of C through Zn is in line with the "normal" population of EMP halo stars, except that it shows a notable underabundance in carbon. The heavy element abundance pattern of LAMOST J110901.22+075441.8 is in agreement with other well studied cool r-II metal-poor giants such as CS 22892-052 and CS 31082-001. The abundances of elements in the range from Ba through Dy match the scaled solar r-process pattern well.LAMOST J110901.22+075441.8 provides the first detailed measurements of neutroncapture elements among r-II stars at such low metallicity with [Fe/H]-3.4, and exhibits similar behavior as other r-II stars in the abundance ratio of Zr/Eu as well as Sr/Eu and Ba/Eu.展开更多
WWTR1,a gene related to the TGF-βsignaling pathway,has been elucidated to be involved in oncogenesis in multiple studies.There is,however,no research on its link to immune infiltration in colon cancer.The TCGA databa...WWTR1,a gene related to the TGF-βsignaling pathway,has been elucidated to be involved in oncogenesis in multiple studies.There is,however,no research on its link to immune infiltration in colon cancer.The TCGA database has identified WWTR1,a gene related to the TGF-βsignaling pathway,which is lowly expressed in colon cancer patients compared to normal subjects.Meanwhile,we produced the Kapan-Meier curve with GEO and the TCGA database,which revealed that colon cancer patients with high WWTR1 expression had a poor prognosis.We discovered that high expression of WWTR1 in colon cancer was associated with clinical stage,pathological T-stage,and lymphatic metastasis after examining the clinical characteristics of colon cancer patients.WWTR1 was found to be an independent predictive factor for colon cancer in a multivariate Cox regression study.Infiltration of immunological cells(B cells,CD8^(+)T cells,CD4^(+)T cells,Macrophage,Neutrophil,Dendritic cells)was linked to WWTR1 expression.In colon cancer,WWTR1 expression was also found to be favorably linked with major immune cell markers.According to an analysis of WWTR1 DCGs,GO,and KEGG enrichment analysis,WWTR1 expression levels were associated with ameboidal-type cell migration,focal adhesion,actin binding,Chemical carcinogenesis-reactive oxygen species,Non-alcoholic fatty liver disease,and Alzheimer disease.These findings imply that WWTR1 is a prognostically valuable and important biomarker for colon cancer,and imply that its expression is strongly linked to colon cancer immune infiltration,making it a potential new target for colon cancer biotherapy.展开更多
We report the detection of a large sample of high-α-metal-rich stars on the low giant branch with 2.6<log g<3.3 dex in the LAMOST-MRS survey.This special group corresponds to an intermediate-age population of 5...We report the detection of a large sample of high-α-metal-rich stars on the low giant branch with 2.6<log g<3.3 dex in the LAMOST-MRS survey.This special group corresponds to an intermediate-age population of 5-9 Gyr based on the[Fe/H]-[C/N]diagram and age-[C/N]calibration.A comparison group is selected to have a solarαratio at super metallicity,which is young and has a narrow age range around 3 Gyr.Both groups have thin-disk like kinematics but the former shows slightly large velocity dispersions.The special group shows a larger extension in a vertical distance toward 1.2 kpc,a second peak at smaller Galactic radius and a larger fraction of super metal rich stars with[Fe/H]>0.2 than the comparison group.These properties strongly indicate its connection with the outer bar/bulge region at R=3-5 kpc.A tentative interpretation of this special group is that its stars were formed in the X-shaped bar/bulge region,close to its corotation radius,where radial migration is the most intense,and brings them to present locations at 9 kpc and beyond.Low eccentricities and slightly outward radial excursions of its stars are consistent with this scenario.Its kinematics(cold)and chemistry([α/Fe]~0.1)further support the formation of the instability-driven X-shaped bar/bulge from the thin disk.展开更多
Possessing multiple stellar populations has been accepted as a common feature of globular clusters(GCs). Different stellar populations manifest themselves with different chemical features,e.g. the well-known O-Na an...Possessing multiple stellar populations has been accepted as a common feature of globular clusters(GCs). Different stellar populations manifest themselves with different chemical features,e.g. the well-known O-Na anti-correlation. Generally, the first(primordial) population has O and Na abundances consistent with those of field stars with similar metallicity; while the second(polluted) population is identified by their Na overabundance and O deficiency. The fraction of the populations is an important constraint on the GC formation scenario. Several methods have been proposed for the classification of GC populations. Here we examine a criterion derived based on the distribution of Galactic field stars, which relies on Na abundance as a function of [Fe/H], to distinguish first and second stellar populations in GCs. By comparing the first population fractions of 17 GCs estimated by the field star criterion with those in the literature derived by methods related to individual GCs, we find that the field star criterion tends to overestimate the first population fractions. The population separation methods,which are related to an individual GC sample, are recommended because the diversity of GCs can be taken into consideration. Currently, more caution should be exercised if one wants to regard field stars as a reference for the identification of a GC population. However, further study on the connection between field stars and GCs populations is still needed.展开更多
We analyze the feasibility of estimating the stellar mass of galaxies by mid-infrared luminosities based on a large sample of galaxies cross-identified from Spitzer SWIRE fields and the SDSS spectrographic survey.We d...We analyze the feasibility of estimating the stellar mass of galaxies by mid-infrared luminosities based on a large sample of galaxies cross-identified from Spitzer SWIRE fields and the SDSS spectrographic survey.We derived the formulae to calculate the stellar mass by using IRAC 3.6μm and 4.5μm luminosities.The massto-luminosity ratios of IRAC 3.6μm and 4.5μm luminosities are more sensitive to the star formation history of galaxies than to other factors,such as the intrinsic extinction,metallicity and star formation rate.To remove the effect of star formation history,we used g-r color to recalibrate the formulae and obtain a better result.Researchers must be more careful when estimating the stellar mass of low metallicity galaxies using our formulae.Due to the emission from dust heated by the hottest young stars,luminous infrared galaxies present higher IRAC 4.5μm luminosities compared to IRAC 3.6μm luminosities.For most of type-Ⅱ AGNs,the nuclear activity cannot enhance 3.6μm and 4.5μm luminosities compared with normal galaxies.Star formation in our AGNhosting galaxies is also very weak,almost all of which are early-type galaxies.展开更多
基金supported by the Science and Technology Beneficiary Program of Ningxia Hui Autonomous Region(No.2023CMG03027)the Ningxia Key Research and Development Program(No.2022BEG03167)the National Natural Science Foundation of China(No.82060275).
文摘Background:This study aimed to portray the atomic intelligence and prognostic implications of differentially expressed genes and their involvement in biological pathways in endometrial carcinoma,with a specific focus on the impacts of exercise on cancer.Methods:We utilized a multi-faceted approach,including volcano plots,Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses,Venn diagrams,protein-protein interaction networks,Kaplan-Meier survival analysis,Gene Set Variety Analysis,and single-cell transcriptomic analysis.Furthermore,we profiled tumor mutational scenes,assessed the prognostic value of immune-related features,and conducted a comprehensive examination of genetic variations and their impact on tumor mutational burden across different cancer types.Multidimensional genomic interactions and methylation elements were also investigated.Using real-time quantitative PCR and immunofluorescence staining,the effects of B-cell lymphoma 2(BCL2)silencing on TNF-αand caspase-3 gene expression were evaluated.Results:Our study identified a noteworthy number of differentially expressed genes in endometrial carcinoma with potential links to athletic performance traits.BCL2 expression levels were found to be associated with survival outcomes,and its changeability across cancers was related to immune cell infiltration and immune checkpoint gene expression.Single-cell investigations uncovered cellular complexity within tumor microenvironments and critical biological pathways in BCL2-overexpressing cells.The expression flow and mutational effect of BCL2 in endometrial carcinoma were characterized,and the prognostic implications of immune-related features were assessed.Hereditary variations,including copy number variations and their relationship with gene expression and tumor mutational burden,were investigated.Multidimensional genomic transaction highlighted the essential role of regulatory genes in cancer pathogenesis.Silencing of the BCL2 gene significantly inhibited the proliferation of HEC-108 cells and promoted apoptosis,as evidenced by decreased TNF-αgene expression and increased caspase-3 gene expression.Immunofluorescence staining further confirmed these results.Conclusion:This study gives a point-by-point understanding of the atomic intelligence and prognostic implications in endometrial carcinoma and across various other cancers.BCL2’s role as a modulatory factor within the tumor-resistant environment and its potential impact on disease prognosis and response to immunotherapy were underscored.The multidimensional genomic analysis provides insights into the complex interaction between genetic and epigenetic variables in cancer,which may shed light on future therapeutic strategies.This study indicates that silencing the BCL2 gene can significantly inhibit tumor cell proliferation and promote apoptosis through the regulation of the TNF-αand caspase-3 pathways.
基金funded by the National Basic Research Program of China (973 Program, 2014CB845700)the National Natural Science Foundation of China (Grant Nos. 11390371)Funding for the project has been provided by the National Development and Reform Commission
文摘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.
基金The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST,now called the Guoshoujing Telescope) is a National Major Scientific Project built by the Chinese Academy of Sciencessupported by the National Natural Science Foundation of China (NSFC) (Grant No.10821061)+2 种基金the National Basic Research Program of China (Program 973Grant No.2007CB815103),and it has made use of the CAS database of SDSS3the Global Networks program of the University of Heidelberg,and from Deutsche Forschungsgemeinschaft under grant CH 214/5-1
文摘Metal-deficient stars are regarded as fossils of the early generation of stars and therefore make crucial observational targets related to stellar astrophysics. They provide fundamental information and insights on properties of the very early stage of the chemical history of the Galaxy and have been investigated for decades. The unique design of the Guoshoujing Telescope (LAMOST), such as its large field and multi-object observational capability, enables it to be an excellent tool for searching for these metal-poor stars in the Milky Way. This work reports the result of test observations which search for metal-poor stars with LAMOST, during which nine candidate metal-poor stars with [Fe/H] ≤ - 1.0 were newly detected based on the low-resolution spectroscopic observations of the LAMOST commissioning data. The sample of stars demonstrates the efficiency of selecting from the input catalog, as well as the ability of LAMOST to enlarge the sample of metal-poor stars in the Milky Way. Furthermore, the sample of stars could be used for future calibrations of the LAMOST stellar pa- rameter pipeline.
基金Supported by the National Natural Science Foundation of China(Grant Nos. 10973021, 10778626 and 10933001)the National Basic Research Development Program of China (Grant No. 2007CB815404)the China Scholarship Council (CSC) (Grant No. 2007104275)
文摘A number of spectroscopic surveys have been carried out or are planned to study the origin of the Milky Way. Their exploitation requires reliable automated methods and softwares to measure the fundamental parameters of the stars. Adopting the ULySS package, we have tested the effect of different resolutions and signal-to- noise ratios (SNR) on the measurement of the stellar atmospheric parameters (effective temperature Teff, surface gravity log g, and metaUicity [Fe/H]). We show that ULySS is reliable for determining these parameters with medium-resolution spectra (R ~2000). Then, we applied the method to measure the parameters of 771 stars selected in the commissioning database of the Guoshoujing Telescope (LAMOST). The results were compared with the SDSS/SEGUE Stellar Parameter Pipeline (SSPP), and we derived precisions of 167 K, 0.34dex, and 0.16dex for Teff, logg and [Fe/H] respectively. Furthermore, 120 of these stars are selected to construct the primary stellar spectral template library (Version 1.0) of LAMOST, and will be deployed as basic ingredients for the LAMOST automated parametrization pipeline.
基金Supported by the National Natural Science Foundation of China
文摘Strongly Mg-enhanced stars with [Mg/Fe] 〉 1.0 show peculiar abundance patterns and hence are of great interest for our understanding of stellar formation and chemical evolution of the Galaxy. A systematic search for strongly Mg-enhanced stars based on low-resolution (R≈2000) spectra from the Sloan Digital Sky Survey (SDSS) is carried out by finding the synthetic spectrum that best matches the observed one in the region of Mg I b lines around λ5170 ,A via a profile matching method. The advantage of our method is that fitting parameters are refined by reproducing the [Mg/Fe] ratios of 47 stars from the very precise high-resolution spectroscopic (HRS) analysis by Nissen & Schuster; and these parameters are crucial to the precision and validity of the derived Mg abundances. As a further check of our method, Mg abun- dances are estimated with our method for member stars in four Galactic globular clus- ters (M92, M 13, M3, M71) which cover the same metallicity range as our sample, and the results are in good agreement with those of HRS analysis in the literature. The val- idation of our method is also demonstrated by the agreement of [Mg/Fe] between our values and those of HRS analysis by Aoki et al. Finally, 33 candidates of strongly Mg- enhanced stars with [Mg/Fe]〉 1.0 are selected from 14 850 F and G stars. Follow-up observations will be carried out on these candidates with high-resolution spectroscopy by large telescopes in the near future, so as to check our selection procedure and to perform a precise and detailed abundance analysis and to explore the origins of these stars.
基金supported by National Key R&D Program of China(Grant No.2019YFA0405502)the Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB09-02)+7 种基金the National Natural Science Foundation of China(Grant Nos.11833006,11473033,11603037,11973049,and 11973052)the international partnership program’s key foreign cooperation project,Bureau of International Cooperation,Chinese Academy of Sciences(Grant No.114A32KYSB20160049)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB34020205)supported by the Astronomical Big Data Joint Research Center,co-founded by the National Astronomical Observatories,Chinese Academy of Sciences and Alibaba Cloudpartial support for this work from grant PHY 14-30152Physics Frontier Center/JINA Center for the Evolution of the Element(JINA-CEE),awarded by the US National Science Foundationpartially supported by the Open Project Program of the Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of SciencesFunding for the project has been provided by the National Development and Reform Commission。
文摘The abundance patterns of r-process-enhanced stars contain key information required to constrain the astrophysical site(s)of r-process nucleosynthesis,and to deepen our understanding of the chemical evolution of our Galaxy.To expand the sample of known r-process-enhanced stars,we have developed a method to search for candidates in the LAMOST medium-resolution(R7500)spectroscopic survey by matching the observed spectra to synthetic templates around the EuⅡline at 6645.1 A.We obtain a sample of 13 metal-poor(-2.35<[Fe/H]<-0.91)candidates from 12209 unique stars with 32774 mediumresolution spectra.These candidates will be further studied by high-resolution follow-up observations in the near future.We describe some extensions of this effort to include larger samples of stars,in particular at lower metallicity,using the strength of the BaⅡline at 6496.9 A.
基金the paper.H.N.L.and G.Z.acknowledge supports by the National Natural Science Foundation of China (Grant Nos.11103030, 11233004 and 11390371)W.A.and T.S.are supported by the JSPS Grant-in-Aid for Scientific Research (S: 23224004)+1 种基金S.H.is supported by the JSPS Grant-in-Aid for Scientific Research (c:26400231)N.C.acknowledges support from Sonderforschungsbereich 881 "The Milky Way System" (subproject A4) of the German Research Foundation (DFG)
文摘We report the discovery of an extremely metal-poor(EMP) giant,LAMOST J110901.22+075441.8, which exhibits a large excess of r-process elements with [Eu/Fe] ~ +1.16. The star is one of the newly discovered EMP stars identified from the LAMOST low-resolution spectroscopic survey and a highresolution follow-up observation with the Subaru Telescope. Stellar parameters and elemental abundances have been determined from the Subaru spectrum. Accurate abundances for a total of 23 elements including 11 neutron-capture elements from Sr through Dy have been derived for LAMOST J110901.22+075441.8. The abundance pattern of LAMOST J110901.22+075441.8 in the range of C through Zn is in line with the "normal" population of EMP halo stars, except that it shows a notable underabundance in carbon. The heavy element abundance pattern of LAMOST J110901.22+075441.8 is in agreement with other well studied cool r-II metal-poor giants such as CS 22892-052 and CS 31082-001. The abundances of elements in the range from Ba through Dy match the scaled solar r-process pattern well.LAMOST J110901.22+075441.8 provides the first detailed measurements of neutroncapture elements among r-II stars at such low metallicity with [Fe/H]-3.4, and exhibits similar behavior as other r-II stars in the abundance ratio of Zr/Eu as well as Sr/Eu and Ba/Eu.
基金supported by the Social Development Projects of Yangzhou(No.YZ2018091)the Major Public Health Projects in Yangzhou+2 种基金Screening Projects of Early Gastrointestinal Diseases(2018)the National Natural Science Foundation of Yangzhou(No.2018YXZX20184,Gastroenterology)Scientific Research Project of Jiangsu Provincial Health Commission(No.M2021039).
文摘WWTR1,a gene related to the TGF-βsignaling pathway,has been elucidated to be involved in oncogenesis in multiple studies.There is,however,no research on its link to immune infiltration in colon cancer.The TCGA database has identified WWTR1,a gene related to the TGF-βsignaling pathway,which is lowly expressed in colon cancer patients compared to normal subjects.Meanwhile,we produced the Kapan-Meier curve with GEO and the TCGA database,which revealed that colon cancer patients with high WWTR1 expression had a poor prognosis.We discovered that high expression of WWTR1 in colon cancer was associated with clinical stage,pathological T-stage,and lymphatic metastasis after examining the clinical characteristics of colon cancer patients.WWTR1 was found to be an independent predictive factor for colon cancer in a multivariate Cox regression study.Infiltration of immunological cells(B cells,CD8^(+)T cells,CD4^(+)T cells,Macrophage,Neutrophil,Dendritic cells)was linked to WWTR1 expression.In colon cancer,WWTR1 expression was also found to be favorably linked with major immune cell markers.According to an analysis of WWTR1 DCGs,GO,and KEGG enrichment analysis,WWTR1 expression levels were associated with ameboidal-type cell migration,focal adhesion,actin binding,Chemical carcinogenesis-reactive oxygen species,Non-alcoholic fatty liver disease,and Alzheimer disease.These findings imply that WWTR1 is a prognostically valuable and important biomarker for colon cancer,and imply that its expression is strongly linked to colon cancer immune infiltration,making it a potential new target for colon cancer biotherapy.
基金supported by the National Natural Science Foundation of China(Nos.11988101,11625313,11890694,11973048 and 11927804)the 2-m Chinese Space Survey Telescope project and the National Key R&D Program of China(No.2019YFA0405502)+2 种基金supported by the Astronomical Big Data Joint Research Center,co-founded by the National Astronomical Observatories,Chinese Academy of Sciences and the Alibaba CloudThe Guo Shou Jing Telescope(the Large Sky Area Multi-Object Fiber Spectroscopic Telescope LAMOST)is a National Major Scientific Project built by the Chinese Academy of Sciencesprovided by the National Development and Reform Commission。
文摘We report the detection of a large sample of high-α-metal-rich stars on the low giant branch with 2.6<log g<3.3 dex in the LAMOST-MRS survey.This special group corresponds to an intermediate-age population of 5-9 Gyr based on the[Fe/H]-[C/N]diagram and age-[C/N]calibration.A comparison group is selected to have a solarαratio at super metallicity,which is young and has a narrow age range around 3 Gyr.Both groups have thin-disk like kinematics but the former shows slightly large velocity dispersions.The special group shows a larger extension in a vertical distance toward 1.2 kpc,a second peak at smaller Galactic radius and a larger fraction of super metal rich stars with[Fe/H]>0.2 than the comparison group.These properties strongly indicate its connection with the outer bar/bulge region at R=3-5 kpc.A tentative interpretation of this special group is that its stars were formed in the X-shaped bar/bulge region,close to its corotation radius,where radial migration is the most intense,and brings them to present locations at 9 kpc and beyond.Low eccentricities and slightly outward radial excursions of its stars are consistent with this scenario.Its kinematics(cold)and chemistry([α/Fe]~0.1)further support the formation of the instability-driven X-shaped bar/bulge from the thin disk.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11303040, 11390371, 11573032 and 1233004)the Strategic Priority Research Program "The Emergence of Cosmological Structures of the Chinese Academy of Sciences" (Grant No. XDB09000000)
文摘Possessing multiple stellar populations has been accepted as a common feature of globular clusters(GCs). Different stellar populations manifest themselves with different chemical features,e.g. the well-known O-Na anti-correlation. Generally, the first(primordial) population has O and Na abundances consistent with those of field stars with similar metallicity; while the second(polluted) population is identified by their Na overabundance and O deficiency. The fraction of the populations is an important constraint on the GC formation scenario. Several methods have been proposed for the classification of GC populations. Here we examine a criterion derived based on the distribution of Galactic field stars, which relies on Na abundance as a function of [Fe/H], to distinguish first and second stellar populations in GCs. By comparing the first population fractions of 17 GCs estimated by the field star criterion with those in the literature derived by methods related to individual GCs, we find that the field star criterion tends to overestimate the first population fractions. The population separation methods,which are related to an individual GC sample, are recommended because the diversity of GCs can be taken into consideration. Currently, more caution should be exercised if one wants to regard field stars as a reference for the identification of a GC population. However, further study on the connection between field stars and GCs populations is still needed.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10833006 and 10773014)the 973 Program grant 2007CB815406
文摘We analyze the feasibility of estimating the stellar mass of galaxies by mid-infrared luminosities based on a large sample of galaxies cross-identified from Spitzer SWIRE fields and the SDSS spectrographic survey.We derived the formulae to calculate the stellar mass by using IRAC 3.6μm and 4.5μm luminosities.The massto-luminosity ratios of IRAC 3.6μm and 4.5μm luminosities are more sensitive to the star formation history of galaxies than to other factors,such as the intrinsic extinction,metallicity and star formation rate.To remove the effect of star formation history,we used g-r color to recalibrate the formulae and obtain a better result.Researchers must be more careful when estimating the stellar mass of low metallicity galaxies using our formulae.Due to the emission from dust heated by the hottest young stars,luminous infrared galaxies present higher IRAC 4.5μm luminosities compared to IRAC 3.6μm luminosities.For most of type-Ⅱ AGNs,the nuclear activity cannot enhance 3.6μm and 4.5μm luminosities compared with normal galaxies.Star formation in our AGNhosting galaxies is also very weak,almost all of which are early-type galaxies.
基金supported by the National Natural Science Foundation of China(31500335)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB31000000).