AIM:To investigate the expression of B7-H1 in human colorectal carcinoma (CRC) to define its regulating effects on T cells in tumor microenvironment.METHODS:One hundred and two paraffin blocks and 33 fresh samples of ...AIM:To investigate the expression of B7-H1 in human colorectal carcinoma (CRC) to define its regulating effects on T cells in tumor microenvironment.METHODS:One hundred and two paraffin blocks and 33 fresh samples of CRC tissues were subject to this study.Immunohistochemistry was performed for B7-H1 and CD3 staining in CRC tissues.Ficoll-Hypaque density gradient centrifugation was used to isolate peripheral blood mononuclear cells of fresh CRC tissues;flow cytometry and immunofluorescence staining were used for detection of regulatory T cells.Data was analyzed with statistical software.RESULTS:Costimulatory molecule B7-H1 was found strongly expressed in CRC tissues,localized in tumor cell membrane and cytoplasm,while weak or none expression of B7-H1 was detected in pared normal colorectal tissues.Meanwhile,CD3 positive T cells were found congregated in CRC tumor nest and stroma.Statistic analysis showed that B7-H1 expression level was negatively correlated to the total T cell density in tumor nest (P<0.0001) and tumor stroma (P=0.0200) of 102 cases of CRC tissues.Among the total T cells,a variable amount of regulatory T cells with a clear Foxp3+ (forkhead box P3) staining could be detected in CRC tissues and patients' blood.Interestingly,in the 33 samples (15 cases of B7-H1 high CRC tissues and 18 cases of B7H1 low CRC tissues) of freshly isolated mononuclear cells from CRC tissues,the percentages of CD4+ Foxp3+ and CD8+ Foxp3+ regulatory T cells were found remarkably higher in B7-H1 high CRC tissues than in B7-H1 low CRC tissues (P=0.0024,P=0.0182),indicating that B7-H1 expression was involved in proliferation of regulatory T cell.No significant difference was found in CRC peripheral blood (P=0.0863,P=0.0678).PD-1 is the specific ligand for B7-H1 pathway transferring inhibitory signal to T cell,which is expressed by activated T cell.Our further analysis of PD-1 expression on T cells in CRC tissues showed that conventional T cells (CD4+ Foxp3/CD8+ Foxp3),which was thought to contribute to the anti-tumor immune response,highly expressed PD-1;while regulatory T cells (CD4+ Foxp3+/CD8+ Foxp3) almost failed to express PD-1.The average percentage of PD-1 expression on regulatory T cells was significantly higher than the percentage of PD-1 on conventional T cells (CD4+ Foxp3 T cell,P<0.0001;CD8+ Foxp3 T cell,P<0.0001).The diverse expression of PD-1 might lead to different fate of T cell subsets in B7-H1 over-expression CRC tumor microenvironment.CONCLUSION:B7-H1 expression in tumor cells can in hibit the conventional T cell proliferation in tumor micro environment through the PD-1 expression on conventiona T cells.展开更多
AIM:To investigate the expression of co-stimulatorymolecule B7-H3 in gastric carcinoma and adenomatissue as well as normal gastric tissue and to explore therelationship between B7-H3 expression and pathologicalfeature...AIM:To investigate the expression of co-stimulatorymolecule B7-H3 in gastric carcinoma and adenomatissue as well as normal gastric tissue and to explore therelationship between B7-H3 expression and pathologicalfeatures and prognosis of gastric carcinoma.METHODS:B7-H3 expression was detected in 102samples of human gastric carcinoma and 10 samples ofgastric adenoma and 10 samples of normal gastric tissueby immunohistochemical assay.Correlation betweenthe expression of B7-H3 and the patients'age,sex,gastric carcinoma locus,tumor size,tissue type,tumorinfiltration depth,differentiation degree,lymph nodemetastasis,and survival time was analyzed.RESULTS:B7-H3 was expressed in all gastric adenomasamples and in 58.8% samples of gastric carcinoma.B7-H3 expression in gastric carcinoma samples wasnot related with the patients'age,sex,lymph nodemetastasis,and tumor size(P>0.05),but with thesurvival time,infiltration depth of tumor and tissue type.CONCLUSION:Detection of B7-H3 expression in gastriccarcinoma tissue is beneficial to the judgment of theprognosis of gastric carcinoma patients and the choice oftreatment.展开更多
Despite its dual role in determining cell fate in a wide array of solid cancer cell lines, autophagy has been robustly shown to suppress or kill acute myeloid leukemia cells via degradation of the oncogenic fusion pro...Despite its dual role in determining cell fate in a wide array of solid cancer cell lines, autophagy has been robustly shown to suppress or kill acute myeloid leukemia cells via degradation of the oncogenic fusion protein that drives leukemogenesis. However, autophagy also induces the demise of acute leukemia cells that do not express the known fusion protein, though the molecular mechanism remains elusive. Nevertheless, since it can induce cooperation with apoptosis and differentiation in response to autophagic signals, autophagy can be manipulated for a better therapy on acute myeloid leukemia.展开更多
AIMTo explore the effects and mechanism of vascular endothelial cadherin (VE-cadherin) on experimental corneal neovascularization (CRNV).METHODSMouse corneas were burned with sodium hydroxide to build a CRNV model. Th...AIMTo explore the effects and mechanism of vascular endothelial cadherin (VE-cadherin) on experimental corneal neovascularization (CRNV).METHODSMouse corneas were burned with sodium hydroxide to build a CRNV model. The burned corneas were locally administrated with anti-mouse VE-cadherin neutralizing antibody. Annexin V and cluster of differentiation 31 (CD31) double staining was used to measure vascular endothelial cell apoptosis with the use of flow cytometry (FCM). The protein expression of NADPH oxidase 2 (Nox2), caspase-3, and protein kinase C (PKC) in the burned corneas were examined by Western blot. Human retinal endothelial cell (HREC) proliferation was detected using a Cell Counting Kit 8 (CCK-8) assay in vitro.RESULTSThe amount of CRNV peaked two weeks after the alkali burn. FCM confirmed that VE-cadherin neutralizing antibody treatment increased CD31 positive cell apoptosis. Western blot revealed that the intracorneal protein expression of Nox2 and caspase-3 were up-regulated, while PKC was down-regulated in the VE-cadherin neutralizing antibody administrated group. CCK-8 assay showed that VE-cadherin neutralizing antibody markedly inhibited HREC proliferation.CONCLUSIONVE-cadherin exhibited an anti-apoptosis effect through enhanced PKC signaling and an enhanced cell proliferation pathway.展开更多
In analyses of protein families that may serve as drug targets,membrane-associated G-protein-coupled receptors(GPCRs)dominate,followed by ion channels,transporters,and—to a lesser extent—membrane-bound enzymes.Howev...In analyses of protein families that may serve as drug targets,membrane-associated G-protein-coupled receptors(GPCRs)dominate,followed by ion channels,transporters,and—to a lesser extent—membrane-bound enzymes.However,various challenges put such membrane proteins among key groups of underutilized opportunities for the application of therapeutic antibodies.Antibodies hold the promise of exquisite specificity,as they are able to target even specific conformations of a particular membrane protein,as well as adaptability through engineering into various antibody formats.However,the ease of raising and isolating specific,effective antibodies targeting membrane proteins depends on many factors.In particular,the generation of specific antibodies is easier when targeting larger,simpler,extracellular domains with greater uniqueness of amino acid sequence.The rareness of such ideal conditions is illustrated by the limited number of approved biologics for targeting GPCRs and other complex membrane proteins.Challenges in developing antibodies to complex membrane proteins such as GPCRs,ion channels,transporters,and membrane-bound enzymes can be addressed by the design of the antigen,antibody-generation strategies,lead optimization technologies,and antibody modalities.A better understanding of the membrane proteins being targeted would facilitate mechanism-based drug discovery.This review describes the advantages and challenges of targeting complex membrane proteins with antibodies and discusses the preparation of membrane protein antigens and antibody generation,illustrated by select examples of success.展开更多
AIM: To investigate the effects of blockade of insulin receptor substrate-1(IRS-1) on the bio-function of tube formation of human choroidal endothelial cells(HCECs).METHODS: Quantitative reverse transcriptionpolymeras...AIM: To investigate the effects of blockade of insulin receptor substrate-1(IRS-1) on the bio-function of tube formation of human choroidal endothelial cells(HCECs).METHODS: Quantitative reverse transcriptionpolymerase chain reaction(RT-PCR) and Western blot were performed to determine the expression level of IRS-1 and phospho-IRS-1 in HCECs. Tube formation of HCECs was analyzed using three dimensional in vitro Matrigel assay with or without IRS-1 blockage via IRS-1 inhibitor(GS-101) and vascular endothelial growth factor receptor 2(VEGFR2) inhibitor. In addition, cell counting kit(CCK)-8 and Transwell migration assay were exerted to analyze the effects of blockade of IRS-1 on the bio-function of proliferation and migration of HCECs, respectively. The apoptosis of HCECs was examined using flow cytometry(FCM).RESULTS: RT-PCR and Western blot revealed that IRS-1 phospho-IRS-1 were expressed in HCECs and the expression level was enhanced by stimulation of VEGF-A. The number of tube formation was decreased significantly in GS-101 treated groups compared to phosphate buffered saline(PBS) treated control groups. Furthermore, both cell proliferation and migration of HCECs were decreased in the presence of GS-101. FCM analysis showed that the apoptosis of HCECs was enhanced when the cells were treated with GS-101. Western blot also showed that the expression level of cleaved-caspase 3 in GS-101 treated group was higher than that in control group.CONCLUSION: Blockade of IRS-1 can inhibit tube formation of HCECs through reducing cell proliferation and migration and promoting cell apoptosis.展开更多
In this paper,we discuss properties of SDSS J1042-0018 which is a broad line active galactic nucleus(AGN)but misclassified as an H II galaxy in the BPT diagram(SDSS J1042-0018 is called a misclassified broad line AGN)...In this paper,we discuss properties of SDSS J1042-0018 which is a broad line active galactic nucleus(AGN)but misclassified as an H II galaxy in the BPT diagram(SDSS J1042-0018 is called a misclassified broad line AGN).The emission lines around Hαand around Hβare well described by different model functions,considering broad Balmer lines to be described by Gaussian or Lorentz functions.Different model functions lead to different determined narrow emission line fiuxes,but the different narrow emission line fiux ratios lead SDSS J1042-0018 as an H II galaxy in the BPT diagram.In order to explain the unique properties of the misclassified broad line AGN SDSS J1042-0018,two methods are proposed,the star-forming contributions and the compressed narrow emission line regions with high electron densities near to critical densities of forbidden emission lines.Fortunately,the strong star-forming contributions can be preferred in SDSS J1042-0018.The misclassified broad line AGN SDSS J1042-0018,well explained by star-forming contributions,could provide further clues on the applications of BPT diagrams to the normal broad line AGNs.展开更多
The fast blue optical transients(FBOTs)are a new population of extragalactic transients of unclear physical origin.A variety of mechanisms has been proposed including failed supernova explosion,shock interaction with ...The fast blue optical transients(FBOTs)are a new population of extragalactic transients of unclear physical origin.A variety of mechanisms has been proposed including failed supernova explosion,shock interaction with a dense medium,young magnetar,accretion onto a compact object and stellar tidal disruption event,but none is conclusive.Here we report the discovery of a possible X-ray quasi-periodicity signal with a period of~250 s(at a significance level of 99.76%)in the brightest FBOT AT2018cow through the analysis of XMM-Newton/PN data.The signal is independently detected at the same frequency in the average power density spectrum from data taken from the Swift telescope,with observations covering from 6 to 37 days after the optical discovery,though the significance level is lower(94.26%).This suggests that the quasi-periodic oscillation(QPO)frequency may be stable over at least 1.1×10^(4)cycles.Assuming the~250 s QPO to be a scaled-down analog of that typically seen in stellar mass black holes,a black hole mass of~103–10^(5)solar masses could be inferred.The overall X-ray luminosity evolution could be modeled with a stellar tidal disruption by a black hole of~10^(4)solar masses,providing a viable mechanism to produce AT2018cow.Our findings suggest that other bright FBOTs may also harbor intermediate-mass black holes.展开更多
Based on the long-term light curves collected from the Catalina Sky Survey(CSS)(from 2005 to 2013)and the All-Sky Automated Survey for Supernovae(ASAS-SN)(from 2014 to 2018),optical quasi-periodic oscillations(QPOs)ab...Based on the long-term light curves collected from the Catalina Sky Survey(CSS)(from 2005 to 2013)and the All-Sky Automated Survey for Supernovae(ASAS-SN)(from 2014 to 2018),optical quasi-periodic oscillations(QPOs)about 300 days can be well determined in the well-known blazar PKS 2155-304 through four different methods:the generalized Lomb-Scargle periodogram(GLSP)method,the weighted wavelet Z-transform technique,the epoch-folded method and the redfit method.The GLSP determined significance level for the periodicity is higher than 99.9999%based on a false alarm probability.The redfit provided confidence level for the periodicity is higher than 99%in the ASAS-SN light curve,after considering the effects of red noise.Based on continuous autoregressive process created artificial light curves,the probability of detecting fake QPOs is lower than 0.8%.The determined optical periodicity of 300 days from the CSS and ASAS-SN light curves is well consistent with the reported optical periodicity in the literature.Moreover,three possible models are discussed to explain the optical QPOs in PKS 2155-304:the relativistic frame-dragging effect,the binary black hole model and the jet precession model.展开更多
Hypokalemia is among the most common electrolyte disorders in clinical practice and severe condition is life-threatening and has received extensive attention in clinical practice. Genetic diagnosis remains the gold st...Hypokalemia is among the most common electrolyte disorders in clinical practice and severe condition is life-threatening and has received extensive attention in clinical practice. Genetic diagnosis remains the gold standard for the diagnosis and identification of hereditary renal tubular diseases. Below is the report of genotyping and diagnosis of a case of secondary Gitelman syndrome (GS) based on next-generation sequencing.展开更多
基金Supported by Grants from the Major State Basic Research Development Program of China 973 Program,No.2007CB512402National Natural Science Foundation of China,No.31100634+1 种基金Natural Science Foundation of Jiangsu Province,No.BK2010161"333" Project of Wuxi City,Jiangsu Province,No.CAE00901-09
文摘AIM:To investigate the expression of B7-H1 in human colorectal carcinoma (CRC) to define its regulating effects on T cells in tumor microenvironment.METHODS:One hundred and two paraffin blocks and 33 fresh samples of CRC tissues were subject to this study.Immunohistochemistry was performed for B7-H1 and CD3 staining in CRC tissues.Ficoll-Hypaque density gradient centrifugation was used to isolate peripheral blood mononuclear cells of fresh CRC tissues;flow cytometry and immunofluorescence staining were used for detection of regulatory T cells.Data was analyzed with statistical software.RESULTS:Costimulatory molecule B7-H1 was found strongly expressed in CRC tissues,localized in tumor cell membrane and cytoplasm,while weak or none expression of B7-H1 was detected in pared normal colorectal tissues.Meanwhile,CD3 positive T cells were found congregated in CRC tumor nest and stroma.Statistic analysis showed that B7-H1 expression level was negatively correlated to the total T cell density in tumor nest (P<0.0001) and tumor stroma (P=0.0200) of 102 cases of CRC tissues.Among the total T cells,a variable amount of regulatory T cells with a clear Foxp3+ (forkhead box P3) staining could be detected in CRC tissues and patients' blood.Interestingly,in the 33 samples (15 cases of B7-H1 high CRC tissues and 18 cases of B7H1 low CRC tissues) of freshly isolated mononuclear cells from CRC tissues,the percentages of CD4+ Foxp3+ and CD8+ Foxp3+ regulatory T cells were found remarkably higher in B7-H1 high CRC tissues than in B7-H1 low CRC tissues (P=0.0024,P=0.0182),indicating that B7-H1 expression was involved in proliferation of regulatory T cell.No significant difference was found in CRC peripheral blood (P=0.0863,P=0.0678).PD-1 is the specific ligand for B7-H1 pathway transferring inhibitory signal to T cell,which is expressed by activated T cell.Our further analysis of PD-1 expression on T cells in CRC tissues showed that conventional T cells (CD4+ Foxp3/CD8+ Foxp3),which was thought to contribute to the anti-tumor immune response,highly expressed PD-1;while regulatory T cells (CD4+ Foxp3+/CD8+ Foxp3) almost failed to express PD-1.The average percentage of PD-1 expression on regulatory T cells was significantly higher than the percentage of PD-1 on conventional T cells (CD4+ Foxp3 T cell,P<0.0001;CD8+ Foxp3 T cell,P<0.0001).The diverse expression of PD-1 might lead to different fate of T cell subsets in B7-H1 over-expression CRC tumor microenvironment.CONCLUSION:B7-H1 expression in tumor cells can in hibit the conventional T cell proliferation in tumor micro environment through the PD-1 expression on conventiona T cells.
基金Supported by the National Natural Science Foundation of China,No.300330540
文摘AIM:To investigate the expression of co-stimulatorymolecule B7-H3 in gastric carcinoma and adenomatissue as well as normal gastric tissue and to explore therelationship between B7-H3 expression and pathologicalfeatures and prognosis of gastric carcinoma.METHODS:B7-H3 expression was detected in 102samples of human gastric carcinoma and 10 samples ofgastric adenoma and 10 samples of normal gastric tissueby immunohistochemical assay.Correlation betweenthe expression of B7-H3 and the patients'age,sex,gastric carcinoma locus,tumor size,tissue type,tumorinfiltration depth,differentiation degree,lymph nodemetastasis,and survival time was analyzed.RESULTS:B7-H3 was expressed in all gastric adenomasamples and in 58.8% samples of gastric carcinoma.B7-H3 expression in gastric carcinoma samples wasnot related with the patients'age,sex,lymph nodemetastasis,and tumor size(P>0.05),but with thesurvival time,infiltration depth of tumor and tissue type.CONCLUSION:Detection of B7-H3 expression in gastriccarcinoma tissue is beneficial to the judgment of theprognosis of gastric carcinoma patients and the choice oftreatment.
基金supported by grants from National Science Foundation of China (No. 31071258)The Ministry of Science and Technology of China (Pre-973 Plan: No. 2011CB512101+1 种基金 863 Plan: No. 2011AA020114)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Despite its dual role in determining cell fate in a wide array of solid cancer cell lines, autophagy has been robustly shown to suppress or kill acute myeloid leukemia cells via degradation of the oncogenic fusion protein that drives leukemogenesis. However, autophagy also induces the demise of acute leukemia cells that do not express the known fusion protein, though the molecular mechanism remains elusive. Nevertheless, since it can induce cooperation with apoptosis and differentiation in response to autophagic signals, autophagy can be manipulated for a better therapy on acute myeloid leukemia.
基金Supported by the National Natural Science Foundation of China (No.81200727No.30972712)+2 种基金Jiangsu Province's Key Provincial Talents Program (No.RC2011104)Suzhou Municipal Natural Science Foundation (No.SYS201448)the Soochow Scholar Project of Soochow University
文摘AIMTo explore the effects and mechanism of vascular endothelial cadherin (VE-cadherin) on experimental corneal neovascularization (CRNV).METHODSMouse corneas were burned with sodium hydroxide to build a CRNV model. The burned corneas were locally administrated with anti-mouse VE-cadherin neutralizing antibody. Annexin V and cluster of differentiation 31 (CD31) double staining was used to measure vascular endothelial cell apoptosis with the use of flow cytometry (FCM). The protein expression of NADPH oxidase 2 (Nox2), caspase-3, and protein kinase C (PKC) in the burned corneas were examined by Western blot. Human retinal endothelial cell (HREC) proliferation was detected using a Cell Counting Kit 8 (CCK-8) assay in vitro.RESULTSThe amount of CRNV peaked two weeks after the alkali burn. FCM confirmed that VE-cadherin neutralizing antibody treatment increased CD31 positive cell apoptosis. Western blot revealed that the intracorneal protein expression of Nox2 and caspase-3 were up-regulated, while PKC was down-regulated in the VE-cadherin neutralizing antibody administrated group. CCK-8 assay showed that VE-cadherin neutralizing antibody markedly inhibited HREC proliferation.CONCLUSIONVE-cadherin exhibited an anti-apoptosis effect through enhanced PKC signaling and an enhanced cell proliferation pathway.
基金Supported by National Natural Science Foundation in China(NSFC No.30771978and No30972712)Qing-Lan Project of Education Bureau of Jiangsu ProvinceSupported by Jiangsu Province's Key Provincial Talents Program,China(No.RC2011104)
基金This work was partly supported by the Cancer Prevention and Research Institute of Texas,USA(PR150551 and RP190561)the Welch Foundation(AU-0042-20030616)+1 种基金The work was also supported by the National Natural Science Foundation of China(31700778 and 31320103918)Jiangsu Province’s Key Laboratory of Medicine(XK201135).
文摘In analyses of protein families that may serve as drug targets,membrane-associated G-protein-coupled receptors(GPCRs)dominate,followed by ion channels,transporters,and—to a lesser extent—membrane-bound enzymes.However,various challenges put such membrane proteins among key groups of underutilized opportunities for the application of therapeutic antibodies.Antibodies hold the promise of exquisite specificity,as they are able to target even specific conformations of a particular membrane protein,as well as adaptability through engineering into various antibody formats.However,the ease of raising and isolating specific,effective antibodies targeting membrane proteins depends on many factors.In particular,the generation of specific antibodies is easier when targeting larger,simpler,extracellular domains with greater uniqueness of amino acid sequence.The rareness of such ideal conditions is illustrated by the limited number of approved biologics for targeting GPCRs and other complex membrane proteins.Challenges in developing antibodies to complex membrane proteins such as GPCRs,ion channels,transporters,and membrane-bound enzymes can be addressed by the design of the antigen,antibody-generation strategies,lead optimization technologies,and antibody modalities.A better understanding of the membrane proteins being targeted would facilitate mechanism-based drug discovery.This review describes the advantages and challenges of targeting complex membrane proteins with antibodies and discusses the preparation of membrane protein antigens and antibody generation,illustrated by select examples of success.
基金Supported by the National Natural Science Foundation in China(No.81671641 No.81970830+6 种基金 No.31600736)Suzhou Municipal Natural Science Foundation(No.SYS201745)Soochow University Doctoral Academic Talents Program(No.5832001313)Jiangsu Provincial Medical Youth Talent(No.QNRC2016718)Jiangsu Provincial Medical Innovation Team(No.CXTDA2017039)Jiangsu Provincial Natural Science Foundation(No.BK20151208)the Soochow Scholar Project of Soochow University(No.R5122001)
文摘AIM: To investigate the effects of blockade of insulin receptor substrate-1(IRS-1) on the bio-function of tube formation of human choroidal endothelial cells(HCECs).METHODS: Quantitative reverse transcriptionpolymerase chain reaction(RT-PCR) and Western blot were performed to determine the expression level of IRS-1 and phospho-IRS-1 in HCECs. Tube formation of HCECs was analyzed using three dimensional in vitro Matrigel assay with or without IRS-1 blockage via IRS-1 inhibitor(GS-101) and vascular endothelial growth factor receptor 2(VEGFR2) inhibitor. In addition, cell counting kit(CCK)-8 and Transwell migration assay were exerted to analyze the effects of blockade of IRS-1 on the bio-function of proliferation and migration of HCECs, respectively. The apoptosis of HCECs was examined using flow cytometry(FCM).RESULTS: RT-PCR and Western blot revealed that IRS-1 phospho-IRS-1 were expressed in HCECs and the expression level was enhanced by stimulation of VEGF-A. The number of tube formation was decreased significantly in GS-101 treated groups compared to phosphate buffered saline(PBS) treated control groups. Furthermore, both cell proliferation and migration of HCECs were decreased in the presence of GS-101. FCM analysis showed that the apoptosis of HCECs was enhanced when the cells were treated with GS-101. Western blot also showed that the expression level of cleaved-caspase 3 in GS-101 treated group was higher than that in control group.CONCLUSION: Blockade of IRS-1 can inhibit tube formation of HCECs through reducing cell proliferation and migration and promoting cell apoptosis.
基金the kind support of Starting Research Fund of Nanjing Normal Universitythe kind support of NSFC-12173020the kind support of Da Chuang project of Nanjing Normal University for undergraduate students。
文摘In this paper,we discuss properties of SDSS J1042-0018 which is a broad line active galactic nucleus(AGN)but misclassified as an H II galaxy in the BPT diagram(SDSS J1042-0018 is called a misclassified broad line AGN).The emission lines around Hαand around Hβare well described by different model functions,considering broad Balmer lines to be described by Gaussian or Lorentz functions.Different model functions lead to different determined narrow emission line fiuxes,but the different narrow emission line fiux ratios lead SDSS J1042-0018 as an H II galaxy in the BPT diagram.In order to explain the unique properties of the misclassified broad line AGN SDSS J1042-0018,two methods are proposed,the star-forming contributions and the compressed narrow emission line regions with high electron densities near to critical densities of forbidden emission lines.Fortunately,the strong star-forming contributions can be preferred in SDSS J1042-0018.The misclassified broad line AGN SDSS J1042-0018,well explained by star-forming contributions,could provide further clues on the applications of BPT diagrams to the normal broad line AGNs.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.11822301,12192220,12192221 and 11833007)support from the NSFC(Grant No.12122306)+1 种基金support from the NSFC(Grant Nos.11733009 and U2031205)support by the science research grants from the China Manned Space Project through No.CMS-CSST-2021-A06。
文摘The fast blue optical transients(FBOTs)are a new population of extragalactic transients of unclear physical origin.A variety of mechanisms has been proposed including failed supernova explosion,shock interaction with a dense medium,young magnetar,accretion onto a compact object and stellar tidal disruption event,but none is conclusive.Here we report the discovery of a possible X-ray quasi-periodicity signal with a period of~250 s(at a significance level of 99.76%)in the brightest FBOT AT2018cow through the analysis of XMM-Newton/PN data.The signal is independently detected at the same frequency in the average power density spectrum from data taken from the Swift telescope,with observations covering from 6 to 37 days after the optical discovery,though the significance level is lower(94.26%).This suggests that the quasi-periodic oscillation(QPO)frequency may be stable over at least 1.1×10^(4)cycles.Assuming the~250 s QPO to be a scaled-down analog of that typically seen in stellar mass black holes,a black hole mass of~103–10^(5)solar masses could be inferred.The overall X-ray luminosity evolution could be modeled with a stellar tidal disruption by a black hole of~10^(4)solar masses,providing a viable mechanism to produce AT2018cow.Our findings suggest that other bright FBOTs may also harbor intermediate-mass black holes.
基金the National Natural Science Foundation of China(Grant Nos.11873032 and 12173020)。
文摘Based on the long-term light curves collected from the Catalina Sky Survey(CSS)(from 2005 to 2013)and the All-Sky Automated Survey for Supernovae(ASAS-SN)(from 2014 to 2018),optical quasi-periodic oscillations(QPOs)about 300 days can be well determined in the well-known blazar PKS 2155-304 through four different methods:the generalized Lomb-Scargle periodogram(GLSP)method,the weighted wavelet Z-transform technique,the epoch-folded method and the redfit method.The GLSP determined significance level for the periodicity is higher than 99.9999%based on a false alarm probability.The redfit provided confidence level for the periodicity is higher than 99%in the ASAS-SN light curve,after considering the effects of red noise.Based on continuous autoregressive process created artificial light curves,the probability of detecting fake QPOs is lower than 0.8%.The determined optical periodicity of 300 days from the CSS and ASAS-SN light curves is well consistent with the reported optical periodicity in the literature.Moreover,three possible models are discussed to explain the optical QPOs in PKS 2155-304:the relativistic frame-dragging effect,the binary black hole model and the jet precession model.
文摘Hypokalemia is among the most common electrolyte disorders in clinical practice and severe condition is life-threatening and has received extensive attention in clinical practice. Genetic diagnosis remains the gold standard for the diagnosis and identification of hereditary renal tubular diseases. Below is the report of genotyping and diagnosis of a case of secondary Gitelman syndrome (GS) based on next-generation sequencing.