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Chemical abundance analysis of 19 barium stars

Research in Astronomy and Astrophysics 2016年第1期16卷 159-174页

作者： Guo-Chao Yang Yan-Chun Liang Monique Spite Yu-Qin Chen Gang Zhao Bo Zhang Guo-Qing Liu Yu-Juan Liu Nian Liu Li-Cai Deng Francois Spite vanessa hill Cai-Xia Zhang College of Physics and Information Engineering Hebei Normal University Shijiazhuang 050024 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China University of Chinese Academy of Sciences Beijing 100049 China GEPI Observatoire de Paris-Meudon 92195 Meudon France Physics Department and Tsinghua Center for Astrophysics Tsinghua University Beijing 100084 China Astronomy Department Beijing Normal University Beijing 100875 China Department of Physics Shijiazhuang University Shijiazhuang 050035 China

We aim at deriving accurate atmospheric parameters and chemical abundances of 19 barium（Ba） stars, including both strong and mild Ba stars, based on the high signal-to-noise ratio and high resolution Echelle spectra obtained from the 2.16 m telescope at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. The chemical abundances of the sample stars were obtained from an LTE, plane-parallel and line-blanketed atmospheric model by inputting the atmospheric parameters（effective temperatures Teff, surface gravities log g, metallicity [Fe/H] and microturbulence velocity ξt） and equivalent widths of stellar absorption lines. These samples of Ba stars are giants as indicated by atmospheric parameters, metallicities and kinematic analysis about UVW velocity. Chemical abundances of 17 elements were obtained for these Ba stars. Their Na, Al, α- and iron-peak elements（O, Na, Mg, Al, Si, Ca,Sc, Ti, V, Cr, Mn, Ni） are similar to the solar abundances. Our samples of Ba stars show obvious overabundances of neutron-capture（n-capture） process elements relative to the Sun. Their median abundances of[Ba/Fe], [La/Fe] and [Eu/Fe] are 0.54, 0.65 and 0.40, respectively. The Y I and Zr I abundances are lower than Ba, La and Eu, but higher than the α- and iron-peak elements for the strong Ba stars and similar to the iron-peak elements for the mild stars. There exists a positive correlation between Ba intensity and [Ba/Fe].For the n-capture elements（Y, Zr, Ba, La）, there is an anti-correlation between their [X/Fe] and [Fe/H]. We identify nine of our sample stars as strong Ba stars with [Ba/Fe]〉0.6 where seven of them have Ba intensity Ba=2-5, one has Ba=1.5 and another one has Ba=1.0. The remaining ten stars are classified as mild Ba stars with 0.17〈[Ba/Fe]〈0.54.

关键词： methods: observational - stars: abundances - stars: atmospheres - stars: chemically peculiar- stars: kinematics and dynamics - stars: late-type

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Gene silencing:Double-stranded RNA mediated mRNA degradation and gene inactivation

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Cell Research 2001年第3期11卷 181-186页

作者： TANG WEI, XIAO YAN LUO, vanessa SANMUELS North Carolina State University, Forest Biotechnology Groap, Raleigh, NC 27695, USA University of North Carolina, Department of Cell and Developmental Biology, ChaPel hill, NC 27599, USA North Carolina State University Forest Biotechnology Group Raleigh USA Department of Cell and Developmental Biology University of North Carolina Chapel Hill USA

The recent development of gene transfer approaches in plants and animals has revealed that transgene can undergo silencing after integration in the genome. Host genes can also be silenced as a consequence of the presence of a homologous transgene. More and more investigations have demonstrated that double- stranded RNA can silence genes by triggering degradation of homologous RNA in the cytoplasm and by directing methylation of homologous nuclear DNA sequences. Analyses of Arabidopsis mutants and plant viral suppressors of silencing are unraveling RNA-silencing mechanisms and are assessing the role of methy- lation in transcriptional and posttranscriptional gene silencing. This review will focus on double-stranded RNA mediated mRNA degradation and gene inactivation in plants.

关键词： Gene silencing double-stranded RNA methylation homologous RNA transgene.

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Decline in subarachnoid haemorrhage volumes associated with the first wave of the COVID- 19 pandemic

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Stroke & Vascular Neurology 2021年第4期6卷 542-552,I0026-I0032页

作者： Thanh N Nguyen Diogo C Haussen Muhammad M Qureshi Hiroshi Yamagami Toshiyuki Fujinaka Ossama Y Mansour Mohamad Abdalkader Michael Frankel Zhongming Qiu Allan Taylor Pedro Lylyk Omer F Eker Laura Mechtouff Michel Piotin Fabricio Oliveira Lima Francisco Mont'Alverne Wazim Izzath Nobuyuki Sakai Mahmoud Mohammaden Alhamza R Al-Bayati Leonardo Renieri Salvatore Mangiafico David Ozretic vanessa Chalumeau Saima Ahmad Umair Rashid Syed Irteza Hussain Seby John Emma Griffin John Thornton Jose Antonio Fiorot Rodrigo Rivera Nadia Hammami Anna M Cervantes-Arslanian Hormuzdiyar H Dasenbrock Huynh Le Vu Viet Quy Nguyen Steven Hetts Romain Bourcier Romain Guile Melanie Walker Malveeka Sharma Don Frei Pascal Jabbour Nabeel Herial Fawaz Al-Mufti Atilla Ozcan Ozdemir Ozlem Aykac Dheeraj Gandhi Chandril Chugh Charles Matouk Pascale Lavoie Randall Edgell Andre Beer-Furlan Michael Chen Monika Killer-Oberpfalzer Vitor Mendes Pereira Patrick Nicholson Vikram Huded Nobuyuki Ohara Daisuke Watanabe Dong Hun Shin Pedro SC Magalhaes Raghid Kikano Santiago Ortega-Gutierrez Mudassir Farooqui Amal Abou-Hamden Tatsuo Amano Ryoo Yamamoto Adrienne Weeks Elena A Cora Rotem Sivan-Hoffmann Roberto Crosa Markus Möhlenbruch Simon Nagel Hosam Al-Jehani Sunil A Sheth Victor S Lopez Rivera James E Siegler Achmad Fidaus Sani Ajit S Puri Anna Luisa Kuhn Gianmarco Bernava Paolo Machi Daniel G Abud Octavio M Pontes-Neto Ajay K Wakhloo Barbara Voetsch Eytan Raz Shadi Yaghi Brijesh P Mehta Naoto Kimura Mamoru Murakami Jin Soo Lee Ji Man Hong Robert Fahed Gregory Walker Eiji Hagashi Steve M Cordina Hong Gee Roh Ken Wong Juan F Arenillas Mario Martinez-Galdamez Jordi Blasco Alejandro Rodriguez Vasquez Luisa Fonseca M Luis Silva Teddy Y Wu Simon John Alex Brehm Marios Psychogios William J Mack Matthew Tenser Tatemi Todaka Miki Fujimura Roberta Novakovic Jun Deguchi Yuri Sugiura Hiroshi Tokimura Rakesh Khatri Michael Kelly Lissa Peeling Yuichi Murayama Hugh Stephen Winters Johnny Wong Mohamed Teleb Jeremy Payne Hiroki Fukuda Kosuke Miyake Junsuke Shimbo Yusuke Sug Neurology RadiologyBoston Medical CenterBostonMassachusettsUSA Neurology Marcus Stroke&Neuroscience CenterGrady Memorial HospitalEmory University School of MedicineAtlantaGAUSA Radiology Radiation OncologyBoston University School of MedicineBostonMassachusettsUSA Neurology National Hospital Organization Osaka National HospitalOsakaJapan Neurosurgery National Hospital Organization Osaka National HospitalOsakaJapan Neurology Alexandria UniversityAlexandriaEgypt Radiology Boston Medical CenterBostonMassachusettsUSA Department of Neurology Xinqiao HospitalChongqingChina Neurosurgery University of Cape TownRondeboschWestern CapeSouth Africa Neurosurgery Interventional NeuroradiologyClinica La Sagrada FamiliaBuenos AiresArgentina Neuroradiologie Neurologie VasculaireHospices Civils de LyonLyonAuvergne-Rhône AlpesFrance Neurologie Vasculaire Hospices Civils de LyonLyonAuvergne-Rhône AlpesFrance Interventional Neuroradiology Fondation Ophtalmologique Adolphe de RothschildParisÎle-de FranceFrance Neurology Hospital Geral de FortalezaFortalezaBrazil Interventional Neuroradiology Hospital Geral de FortalezaFortalezaBrazil Neuroradiology Nottingham University Hospitals NHS TrustNottinghamUK Department of Neurosurgery Kobe City Medical Center General HospitalKobeHyogoJapan Interventional Neurovascular Unit University Hospital CareggiFirenzeToscanaItaly Neuroradiology University Hospital Centre ZagrebZagrebCroatia Interventional Neuroradiology Hopital BicetreLe Kremlin-BicetreFrance Stroke and Interventional Neuroradiology Lahore General HospitalLahorePakistan Neurological Institute Cleveland Clinic Abu DhabiAbu DhabiUAE Department of Radiology Beaumont HospitalDublinIreland Neurology Stroke UnitHospital-Estadual CentralVitoriaBrazil Neuroradiology Instituto de Neurocirugia Dr AsengoSantiagoChile Interventional Neuroradiology Institut National de NeurologieTunisTunisia Neurology Boston Medical CenterBostonMassachusettsUSA Neurosurgery Boston Medical Center

Background During the COVID-19 pandemic,decreased volumes of stroke admissions and mechanical thrombectomy were *** study’s objective was to examine whether subarachnoid haemorrhage(SAH)hospitalisations and ruptured aneurysm coiling interventions demonstrated similar *** We conducted a cross-sectional,retrospective,observational study across 6 continents,37 countries and 140 comprehensive stroke *** with the diagnosis of SAH,aneurysmal SAH,ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases,10th Revision,*** 3-month cumulative volume,monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before(1 year and immediately before)and during the pandemic,defined as 1 March-31 May *** prior 1-year control period(1 March-31 May 2019)was obtained to account for seasonal *** There was a significant decline in SAH hospitalisations,with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic,representing a relative decline of 22.5%(95%CI−24.3%to−20.7%,p<0.0001).Embolisation of ruptured aneurysms declined with 1170-1035 procedures,respectively,representing an 11.5%(95%CI−13.5%to−9.8%,p=0.002)relative *** analysis was noted for aneurysmal SAH hospitalisation decline from 834 to 626 hospitalisations,a 24.9%relative decline(95%CI−28.0%to−22.1%,p<0.0001).A relative increase in ruptured aneurysm coiling was noted in low coiling volume hospitals of 41.1%(95%CI 32.3%to 50.6%,p=0.008)despite a decrease in SAH admissions in this *** There was a relative decrease in the volume of SAH hospitalisations,aneurysmal SAH hospitalisations and ruptured aneurysm embolisations during the COVID-19 *** findings in SAH are consistent with a decrease in other emergencies,such as stroke and myocardial infarction.

关键词： diagnosis representing subarachnoid

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