检索结果-内蒙古大学图书馆

arXiv 2020年

作者： Fu, Huazhu Li, Fei Sun, Xu Cao, Xingxing Liao, Jingan Orlando, José Ignacio Tao, Xing Li, Yuexiang Zhang, Shihao Tan, Mingkui Yuan, Chenglang Bian, Cheng Xie, Ruitao Li, Jiongcheng Li, Xiaomeng Wang, Jing Geng, Le Li, Panming Hao, Huaying Liu, Jiang Kong, Yan Ren, Yongyong Bogunović, Hrvoje Zhang, Xiulan Xu, Yanwu State Key Laboratory Zhongshan Ophthalmic Center Sun Yat-sen University Guangzhou510060 China Inception Institute of Artificial Intelligence Abu Dhabi United Arab Emirates Intelligent Healthcare Unit Baidu Beijing China School of Computer Science and Engineering South China University of Technology GuangzhouGuangdong China National Scientific and Technical Research Council CONICET Argentina Tandil Argentina School of Computer Science and Technology Hangzhou Dianzi University Hangzhou China Tencent Jarvis Lab Shenzhen China School of Software Engineering South China University of Technology Guangzhou China School of Biomedical Engineering Health Science Center Shenzhen University Shenzhen China School of Electronic and Information Engineering Shenzhen University Shenzhen China Department of Computer Science and Engineering Chinese University of Hong Kong Hong Kong School of Electronic and Information Engineering Soochow University Suzhou China Ningbo University Zhejiang China Ningbo Institute of Industrial Technology Chinese Academy of Sciences Zhejiang China Southern University of Science and Technology Shenzhen China Shanghai Jiaotong University Shanghai China Laboratory for Ophthalmic Image Analysis Department of Ophthalmology Medical University of Vienna Vienna Austria

Angle closure glaucoma (ACG) is a more aggressive disease than open-angle glaucoma, where the abnormal anatomical structures of the anterior chamber angle (ACA) may cause an elevated intraocular pressure and gradually leads to glaucomatous optic neuropathy and eventually to visual impairment and blindness. Anterior Segment Optical Coherence Tomography (AS-OCT) imaging provides a fast and contactless way to discriminate angle closure from open angle. Although many medical image analysis algorithms have been developed for glaucoma diagnosis, only a few studies have focused on AS-OCT imaging. In particular, there is no public AS-OCT dataset available for evaluating the existing methods in a uniform way, which limits the progress in the development of automated techniques for angle closure detection and assessment. To address this, we organized the Angle closure Glaucoma Evaluation challenge (AGE), held in conjunction with MICCAI 2019. The AGE challenge consisted of two tasks: scleral spur localization and angle closure classification. For this challenge, we released a large data of 4800 annotated AS-OCT images from 199 patients, and also proposed an evaluation framework to benchmark and compare different models. During the AGE challenge, over 200 teams registered online, and more than 1100 results were submitted for online evaluation. Finally, eight teams participated in the onsite challenge. In this paper, we summarize these eight onsite challenge methods and analyze their corresponding results in the two tasks. We further discuss limitations and future directions. In the AGE challenge, the top-performing approach had an average Euclidean Distance of 10 pixel (10µm) in scleral spur localization, while in the task of angle closure classification, all the algorithms achieved the satisfactory performances, especially, 100% accuracy rate for top-two performances. These artificial intelligence techniques were shown to have the potential to enable new developments in AS-OCT

关键词： Ophthalmology

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Constraining ultralight vector dark matter with the Parkes Pulsar Timing Array second data release

arXiv

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arXiv 2022年

作者： Wu, Yu-Mei Chen, Zu-Cheng Huang, Qing-Guo Zhu, Xingjiang Bhat, N.D. Ramesh Feng, Yi Hobbs, George Manchester, Richard N. Russell, Christopher J. Shannon, R.M. School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study UCAS Hangzhou310024 China School of Physical Sciences University of Chinese Academy of Sciences No. 19A Yuquan Road Beijing100049 China CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing100190 China Department of Astronomy Beijing Normal University Beijing100875 China Advanced Institute of Natural Sciences Beijing Normal University Zhuhai519087 China International Centre for Radio Astronomy Research Curtin University BentleyWA6102 Australia Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China Australia Telescope National Facility CSIRO Astronomy and Space Science P.O. Box 76 EppingNSW1710 Australia CSIRO Scientific Computing Australian Technology Park Locked Bag 9013 AlexandriaNSW1435 Australia Centre for Astrophysics and Supercomputing Swinburne University of Technology HawthornVIC3122 Australia Australia

Composed of ultralight bosons, fuzzy dark matter provides an intriguing solution to challenges that the standard cold dark matter model encounters on sub-galactic scales. The ultralight dark matter with mass m ∼ 10−23eV will induce a periodic oscillation in gravitational potentials with a frequency in the nanohertz band, leading to observable effects in the arrival times of radio pulses from pulsars. Unlike scalar dark matter, pulsar timing signals induced by the vector dark matter are dependent on the oscillation direction of the vector fields. In this work, we search for ultralight vector dark matter in the mass range of [2 × 10−24, 2 × 10−22 ]eV through its gravitational effect in the Parkes Pulsar Timing Array (PPTA) second data release. Since no statistically significant detection is made, we place 95% upper limits on the local dark matter density as ρVF . 5 GeV/cm3 for m . 10−23 eV. As no preferred direction is found for the vector dark matter, these constraints are comparable to those given by the scalar dark matter search with an earlier 12-year data set of PPTA. Copyright © 2022, The Authors. All rights reserved.

关键词： Vectors

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α-enhanced Astrochemistry: The Carbon cycle in extreme galactic conditions

arXiv

引用

arXiv 2023年

作者： Bisbas, Thomas G. Zhang, Zhi-Yu Gjergo, Eda Zhao, Ying-He Luo, Gan Quan, Donghui Jiang, Xue-Jian Sun, Yichen Topkaras, Theodoros Li, Di Guo, Ziyi Research Center for Intelligent Computing Platforms Zhejiang Lab Hangzhou311100 China School of Astronomy and Space Science Nanjing University Nanjing China Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Ministry of Education Nanjing China Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory of Radio Astronomy and Technology Chinese Academy of Sciences A20 Datun Road Chaoyang District Beijing100101 China Institut de Radioastronomie Millimetrique Domaine Universitaire de Grenoble 300 rue de la Piscine Saint-Martin d'Héres38406 France Xinjiang Astronomical Observatory Chinese Academy of Sciences No. 150 Science 1-Street Urumqi830011 China I. Physikalisches Institut Universität zu Köln Zülpicher Straße 77 Köln50937 Germany CAS Key Laboratory of FAST National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China NAOC-UKZN Computational Astrophysics Centre University of KwaZulu-Natal Durban4000 South Africa

Astrochemistry has been widely developed as a power tool to probe physical properties of the interstellar medium (ISM) in various conditions of the Milky Way (MW) Galaxy, and in near and distant galaxies. Most current studies conventionally apply linear scaling to all elemental abundances based on the gas-phase metallicity. However, these elements, including carbon and oxygen, are enriched differentially by stellar nucleosynthesis and the overall galactic chemical evolution, evident from α-enhancement in multiple galactic observations such as starbursts, high-redshift star-forming galaxies, and low-metallicity dwarfs. We perform astrochemical modeling to simulate the impact of an α-enhanced ISM gas cloud on the abundances of the three phases of carbon (C+, C, CO) dubbed as 'the carbon cycle'. The ISM environmental parameters considered include two cosmic-ray ionization rates (ζCR = 10−17 and 10−15 s−1), two isotropic FUV radiation field strengths (χ/χ0 = 1 and 102), and (sub-)linear dust-to-gas relations against metallicity, mimicking the ISM conditions of different galaxy types. In galaxies with [C/O] + all decrease in both abundances and emission, though with differential biases. The low-J CO emission is found to be the most stable tracer for the molecular gas, while C and C+ trace H2 gas only under limited conditions, in line with recent discoveries of [Ci]-dark galaxies. We call for caution when using [Cii] 158μm and [Ci](1-0) as alternative H2-gas tracers for both diffuse and dense gas with non-zero [C/O] ratios. Copyright © 2023, The Authors. All rights reserved.

关键词： Galaxies

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Age of FGK Dwarfs Observed with LAMOST and GALAH: Considering the Oxygen Enhancement

arXiv

引用

arXiv 2023年

作者： Sun, Tiancheng Ge, Zhishuai Chen, Xunzhou Bi, Shaolan Li, Tanda Zhang, Xianfei Li, Yaguang Wu, Yaqian Bird, Sarah A. Ferguson, J.W. Zhou, Jianzhao Ye, Lifei Long, Liu Zhang, Jinghua Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Beijing102206 China Department of Astronomy Beijing Normal University Beijing100875 China Beijing Planetarium Beijing Academy of Science and Technology Beijing100044 China Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China School of Physics and Astronomy University of Birmingham BirminghamB15 2TT United Kingdom School of Physics University of Sydney NSW2006 Australia Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences A20 Datun Rd. Chaoyang District Beijing100101 China Center for Astronomy and Space Sciences China Three Gorges University Yichang443002 China Department of Physics Wichita State University WichitaKS67260-0032 United States

Varying oxygen abundance could impact the modeling-inferred ages. This work aims to estimate the ages of dwarfs considering observed oxygen abundance. To characterize 67,503 LAMOST and 4,006 GALAH FGK-type dwarf stars, we construct a grid of stellar models which take into account oxygen abundance as an independent model input. Compared with ages determined with commonly-used α-enhanced models, we find a difference of ∼9% on average when the observed oxygen abundance is considered. The age differences between the two types of models are correlated to [Fe/H] and [O/α], and they are relatively significant on stars with [Fe/H] −0.6 dex. Generally, varying 0.2 dex in [O/α] will alter the age estimates of metal-rich (−0.2 Copyright © 2023, The Authors. All rights reserved.

关键词： Stars

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Photochemical origin of SiC2 in the circumstellar envelope of carbon-rich AGB stars revealed by ALMA

arXiv

引用

arXiv 2023年

作者： Feng, Yanan Li, Xiaohu Millar, Tom J. Szczerba, Ryszard Wang, Ke Quan, Donghui Qin, Shengli Fang, Xuan Tuo, Juan Miao, Zhenzhen Ma, Rong Xu, Fengwei Sun, Jingfei Jiang, Biwei Chang, Qiang Yang, Jianchao Hou, Gao-Lei Li, Fangfang Zhang, Yong Xinjiang Astronomical Observatory Chinese Academy of Sciences China University of Chinese Academy of Sciences China Key Laboratory of Radio Astronomy Chinese Academy of Sciences China Astrophysics Research Centre School of Mathematics and Physics Queen’s University Belfast United Kingdom Nicolaus Copernicus Astronomical Center Polish Academy of Sciences Poland China Research Center for Intelligent Computing Platforms Zhejiang Laboratory China Department of Astronomy Yunnan University China National Astronomical Observatories Chinese Academy of Sciences China Department of Physics Faculty of Science The University of Hong Kong Hong Kong Laboratory for Space Research Faculty of Science The University of Hong Kong Hong Kong China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University China Department of Astronomy Beijing Normal University China School of Physics and Optoelectronic Engineering Shandong University of Technology China MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter School of Physics Xi’an Jiaotong University China School of Physics and Astronomy Sun Yat-sen University China 150 Science 1-Street Xinjiang Urumqi830011 China

Whether SiC2 is a parent species, that is formed in the photosphere or as a by-product of high-temperature dust formation, or a daughter species, formed in a chemistry driven by the photodestruction of parent species in the outer envelope, has been debated for a long time. Here, we analyze the ALMA observations of four SiC2 transitions in the CSEs of three C-rich AGB stars (AI Vol, II Lup, and RAFGL 4211), and found that SiC2 exhibits an annular, shell-like distribution in these targets, suggesting that SiC2 can be a daughter species in the CSEs of carbon-rich AGB stars. The results can provide important references for future chemical models. Copyright © 2023, The Authors. All rights reserved.

关键词： Stars

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FAST observations of an extremely active episode of FRB 20201124A: III. Polarimetry

arXiv

引用

arXiv 2022年

作者： Jiang, Jin-Chen Wang, Wei-Yang Xu, Heng Xu, Jiang-Wei Zhang, Chun-Feng Wang, Bo-Jun Zhou, De-Jiang Zhang, Yong-Kun Niu, Jia-Rui Lee, Ke-Jia Zhang, Bing Han, Jin-Lin Li, Di Zhu, Wei-Wei Dai, Zi-Gao Feng, Yi Jing, Wei-Cong Li, Dong-Zi Luo, Rui Miao, Chen-Chen Niu, Chen-Hui Tsai, Chao-Wei Wang, Fa-Yin Wang, Pei Xu, Ren-Xin Yang, Yuan-Pei Yang, Zong-Lin Yao, Ju-Mei Yuan, Mao Department of Astronomy Peking University Beijing100871 China National Astronomical Observatories Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100101 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China School of Astronomy University of Chinese Academy of Sciences Beijing100049 China Department of Physics and Astronomy University of Nevada Las VegasNV89154 United States CAS Key Laboratory of FAST NAOC Chinese Academy of Sciences Beijing100101 China Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China School of Astronomy and Space Science Nanjing University Nanjing210093 China Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Ministry of Education China Cahill Center for Astronomy and Astrophysics MC 249-17 California Institute of Technology PasadenaCA91125 United States CSIRO Space and Astronomy PO Box 76 EppingNSW1710 Australia South-Western Institute For Astronomy Research Yunnan University Yunnan 650504 China

As the third paper in the multiple-part series, we report the statistical properties of radio bursts detected from the repeating fast radio burst (FRB) source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio telescope (FAST) during an extremely active episode between the 25th and the 28th of September 2021 (UT). We focus on the polarisation properties of 536 bright bursts with S/N > 50. We found that the Faraday rotation measures (RMs) monotonically dropped from −579 rad m−2 to −605 rad m−2 in the 4-day window. The RM values were compatible with the values (−300 to −900 rad m−2 ) reported 4 month ago (Xu et al. 2022). However, the RM evolution rate in the current observation window was at least an order of magnitude smaller than the one (∼ 500 rad m−2 day−1) previously reported during the rapid RM-variation phase, but is still higher than the one (≤ 1 rad m−2day−1 ) during the later RM no-evolution phase. The bursts of FRB 20201124A were highly polarised with the total degree of polarisation (circular plus linear) greater than 90% for more than 90% of all bursts. The distribution of linear polarisation position angles (PAs), degree of linear polarisation (L/I), and degree of circular polarisation (V/I) can be characterised with unimodal distribution functions. During the observation window, the distributions became wider with time, i.e. with larger scatter, but the centroids of the distribution functions remained nearly constant. For individual bursts, significant PA variations (confidence level 5-σ) were observed in 33% of all bursts. The polarisation of single pulses seems to follow certain complex trajectories on the Poincaré sphere, which may shed light on the radiation mechanism at the source or the plasma properties along the path of FRB propagation. Copyright © 2022, The Authors. All rights reserved.

关键词： Polarization

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Mapping Observations of Peptide-like molecules around Sagittarius B2

arXiv

引用

arXiv 2023年

作者： Zheng, Siqi Li, Juan Wang, Junzhi Wang, Yao Gao, Feng Quan, Donghui Du, Fujun Wu, Yajun Bergin, Edwin Li, Yuqiang Shanghai Astronomical Observatory Chinese Academy of Sciences No. 80 Nandan Road Shanghai200030 China Key Laboratory of Radio Astronomy Chinese Academy of Sciences Nanjing210033 China School of Astronomy and Space Sciences University of Chinese Academy of Sciences No. 19A Yuquan Road Beijing100049 China Guangxi Key Laboratory for Relativistic Astrophysics Department of Physics Guangxi University Nanning530004 China Purple Mountain Observatory Chinese Academy of Sciences 10 Yuanhua Road Nanjing210023 China Hamburger Sternwarte Universität Hamburg Gojenbergsweg 112 HamburgD-21029 Germany Giessenbachstr. 1 GarchingD-85748 Germany Xinjiang Astronomical Observatory Chinese Academy of Sciences 150 Science 1-Street Urumqi830011 China Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China School of Astronomy and Space Science University of Science and Technology of China Hefei230026 China Department of Astronomy University of Michigan Ann ArborMI48109 United States

Peptide-like molecule, which has a close connection with the origin of life, has been detected in universe. Mapping observations of HCONH2 and CH3CONH2, two simplest peptide-like molecules, are performed towards Sagittarius B2 (Sgr B2) complex with the IRAM 30m telescope. Seven transitions of HCONH2 and five transitions of CH3CONH2 are used in analysis. The spatial distribution of excitation temperature and column density of HCONH2 in the molecular envelope of Sgr B2 are obtained by the rotation diagrams. Assuming the same excitation temperature as HCONH2, the column densities of CH3CONH2 are also calculated. The results show that excitation temperature ranges from 6 K to 46 K in the molecular envelope of Sgr B2. The abundance ratio between HCONH2 and CH3CONH2 are calculated to explore the relationship among them, as well as HNCO mentioned in our pervious research. The abundance ratio of CH3CONH2/HCONH2 varies from 10% to 20%, while that of HCONH2/HNCO ranges from 1.5% to 10%. CH3CONH2 is enhanced with respect to HCONH2 in the northwest region of Sgr B2. One transition of H13CONH2 is detected toward 12 positions of Sgr B2, from which a 12C/13C ratio of 28.7 is obtained. A time-dependent chemical model with a short duration of X-ray burst is used to explain the observed abundances of HCONH2 and CH3CONH2, with the best fitting result at Tdust = 53-56 K. More chemical reactions are required to be included into the model since the modeled abundance is lower than the observed one at the observed Tdust © 2023, CC BY-SA.

关键词： Peptides

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FAST observations of an extremely active episode of FRB 20201124A: IV. Spin Period Search

arXiv

引用

arXiv 2022年

作者： Niu, Jia-Rui Zhu, Wei-Wei Zhang, Bing Yuan, Mao Zhou, De-Jiang Zhang, Yong-Kun Jiang, Jin-Chen Han, J.L. Li, Di Lee, Ke-Jia Wang, Pei Feng, Yi Li, Dong-Zi Luo, Rui Wang, Fa-Yin Dai, Zi-Gao Miao, Chen-Chen Niu, Chen-Hui Xu, Heng Zhang, Chun-Feng Wang, Wei-Yang Wang, Bo-Jun Xu, Jiang-Wei National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China University of Chinese Academy of Sciences Beijing China Institute for Frontier in Astronomy and Astrophysics Beijing Normal University Beijing102206 China Department of Physics and Astronomy University of Nevada Las VegasNV89154 United States Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China Department of Astronomy Peking University Beijing100871 China Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China Cahill Center for Astronomy and Astrophysics MC 249-17 California Institute of Technology PasadenaCA91125 United States CSIRO Space and Astronomy PO Box 76 EppingNSW1710 Australia School of Astronomy and Space Science Nanjing University Nanjing210093 China Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Ministry of Education China Department of Astronomy University of Science and Technology of China Hefei230026 China

We report the properties of more than 800 bursts detected from the repeating fast radio burst (FRB) source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio telescope (FAST) during an extremely active episode on UTC September 25th-28th, 2021 in a series of four papers. In this fourth paper of the series, we present a systematic search of the spin period and linear acceleration of the source object from both 996 individual pulse peaks and the dedispersed time series. No credible spin period was found from this data set. We rule out the presence of significant periodicity in the range between 1 ms to 100 s with a pulse duty cycle −2 in each of the four one-hour observing sessions, and up to 0.6 m s−2 in all 4 days. These searches contest theoretical scenarios involving a 1 ms to 100 s isolated magnetar/pulsar with surface magnetic field 15 G and a small duty cycle (such as in a polar-cap emission mode) or a pulsar with a companion star or black hole up to 100 M☉ and Pb > 10 hours. We also perform a periodicity search of the fine structures and identify 53 unrelated millisecond-timescale"periods" in multi-components with the highest significance of 3.9 σ. The"periods" recovered from the fine structures are neither consistent nor harmonically related. Thus they are not likely to come from a spin period. We caution against claiming spin periodicity with significance below ∼ 4 σ with multi-components from one-off FRBs. We discuss the implications of our results and the possible connections between FRB multi-components and pulsar micro-structures. © 2022, CC BY.

关键词： Pulsars

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Reciprocating Magnetic Fields in the Pulsar Wind Observed from the Black Widow Pulsar J1720−0534

arXiv

引用

arXiv 2023年

作者： Miao, Chen-Chen Blackmon, Victoria Zhu, Wei-Wei Li, Dong-Zi Ge, Mingyu You, Xiao-Peng McLaughlin, Maura Li, Di Wang, Na Wang, Pei Niu, Jia-Rui Cruces, M. Yuan, Jian-Ping Bai, Jun-Tao Champion, D.J. Chen, Yu-Tong Chi, Ming-Min Freire, P.C.C. Feng, Yi Gan, Zhen-Ye Kramer, M. Kou, Fei-Fei Li, Yu-Xi Miao, Xue-Li Meng, Ling-Qi Niu, Chen-Hui Sun, Sheng-Nan Sun, Zhong-Yi Tedila, H.M. Wang, Shuang-Qiang Wu, Qing-Dong Wang, Jing-Bo Wen, Zhi-Gang Wang, Shen Wang, Ya-Biao Wang, Cheng-Jie Xue, Meng-Yao Yue, You-Ling Yuan, Mao Yao, Ju-Mei Yan, Wen-Ming Zhao, Ru-Shuang Zhang, Lei Zhao, De National Astronomical Observatories Chinese Academy of Sciences Beijing100012 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China West Virginia University 1500 University Ave MorgantownWV26506 United States Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Beijing102206 China Cahill Center for Astronomy and Astrophysics California Institute of Technology 1216 E California Boulevard PasadenaCA91125 United States Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China School of Physical Science and Technology Southwest University Chongqing400715 China Research Center for Intelligent Computing Platforms Zhejiang Laboratory Hangzhou311100 China Xinjiang Astronomical Observatory Chinese Academy of Sciences Xinjiang Urumqi830011 China Max-Planck Institut für Radioastronomie Auf dem Hügel 69 BonnD-53121 Germany School of Computer Science Fudan University Shanghai200433 China Guizhou Normal University Guiyang550001 China College of Physical Science and Technology Central China Normal University Wuhan430079 China Institute of Optoelectronic Technology Lishui University Zhejiang Lishui323000 China Tencent Youtu Lab Tencent Youtu Lab Shanghai200233 China

We report the radio observations of the eclipsing black widow pulsar J1720−0534, a 3.26 ms pulsar in orbit with a low mass companion of mass 0.029 to 0.034 M☉. We obtain the phase-connected timing ephemeris and polarization profile of this millisecond pulsar (MSP) using the Five-hundred-meter Aperture Spherical Radio Telescope (FAST), the Green Bank Telescope (GBT), and the Parkes Telescope. For the first time from such a system, an oscillatory polarisation angle change was observed from a particular eclipse egress with partial depolarization, indicating 10-milliGauss-level reciprocating magnetic fields oscillating in a length scale of 5×103 km (assuming an orbital inclination angle of 90 degrees) outside the companion’s magnetosphere. The dispersion measure variation observed during the ingresses and egresses shows the rapid raising of the electron density in the shock boundary between the companion’s magnetosphere and the surrounding pulsar wind. We suggest that the observed oscillatory magnetic fields originate from the pulsar wind outside the companion’s magnetosphere. © 2023, CC BY-NC-ND.

关键词： Magnetic fields

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Click-iG: Simultaneous Enrichment and Profiling of Intact N-linked, O-GalNAc, and O-GlcNAcylated Glycopeptides

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Angewandte Chemie 2023年第36期135卷

作者： Dr. Jialin Liu Dr. Bo Cheng Dr. Xinqi Fan Xinyue Zhou Jiankun Wang Dr. Wen Zhou Hengyu Li Dr. Wenfeng Zeng Prof. Pengyuan Yang Prof. Xing Chen College of Chemistry and Molecular Engineering Beijing National Laboratory for Molecular Sciences Peking-Tsinghua Center for Life Sciences Synthetic and Functional Biomolecules Center and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Peking University Beijing 100871 China Institute of Biomedical Sciences and Department of Chemistry Fudan University Shanghai 200433 China Key Lab of Intelligent Information Processing of Chinese Academy of Sciences (CAS) and Institute of Computing Technology CAS Beijing 100190 China Deseased

Proteins are ubiquitously modified with glycans of varied chemical structures through distinct glycosidic linkages, making the landscape of protein glycosylation challenging to map. Profiling of intact glycopeptides with mass spectrometry (MS) has recently emerged as a powerful tool for revealing matched information of the glycosylation sites and attached glycans (i.e., intact glycosites), but is largely limited to individual glycosylation types. Herein, we describe Click-iG, which integrates metabolic labeling of glycans with clickable unnatural sugars, an optimized MS method, and a tailored version of pGlyco3 software to enable simultaneous enrichment and profiling of three types of intact glycopeptides: N-linked, mucin-type O-linked, and O-GlcNAcylated glycopeptides. We demonstrate the utility of Click-iG by the identification of thousands of intact glycosites in cell lines and living mice. From the mouse lung, heart, and spleen, a total of 2053 intact N-glycosites, 262 intact O-GalNAc glycosites, and 1947 O-GlcNAcylation sites were identified. Click-iG-enabled comprehensive coverage of the protein glycosylation landscape lays the foundation for interrogating crosstalk between different glycosylation pathways.

关键词： Glycoproteomics Glycosylation Intact Glycosites Metabolic Labeling Unnatural Glycans

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