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1Boundary-processing-technique in EMD method and Hilbert transform显示文摘By virtue of neural network, a series of signals is extended forward and backward, as a result, two additional maxima and two additional minima are obtained at both ends of the original data set, with which the EMD decomposition can be exactly achieved with cubic spline interpolation. Meanwhile, by using of neural network every IMF component can also be extended forward and backward, which effectively restrains the end effect, thus the veracious Hilbert spectra are achieved. Verifications of the sample signals and the actual surface elevation of sea waves show that the present extension method is relatively accurate.DENG Yongjun, WANG Wei, QIAN Chengchun, WANG Zhong & DAI DejunNetwork Center, Ocean University of Qingdao. Qingdao 266003, China Physical Oceanography Laboratory, Ocean Universily of Qingdao, Qingdao 266003, China 2001Chinese Science Bulletin2001,46,11:91
2Preliminary assessment of the navigation and positioning performance of BeiDou regional navigation satellite system显示文摘BeiDou regional navigation satellite system(BDS)also called BeiDou-2 has been in full operation since December 27,2012.It consists of 14 satellites,including 5 satellites in Geostationary Orbit(GEO),5 satellites in Inclined Geosynchronous Orbit(IGSO),and 4 satellites in Medium Earth Orbit(MEO).In this paper,its basic navigation and positioning performance are evaluated preliminarily by the real data collected in Beijing,including satellite visibility,Position Dilution of Precision(PDOP)value,the precision of code and carrier phase measurements,the accuracy of single point positioning and differential positioning and ambiguity resolution(AR)performance,which are also compared with those of GPS.It is shown that the precision of BDS code and carrier phase measurements are about 33 cm and 2 mm,respectively,which are comparable to those of GPS,and the accuracy of BDS single point positioning has satisfied the design requirement.The real-time kinematic positioning is also feasible by BDS alone in the opening condition,since its fixed rate and reliability of single-epoch dual-frequency AR is comparable to those of GPS.The accuracy of BDS carrier phase differential positioning is better than 1 cm for a very short baseline of 4.2 m and 3 cm for a short baseline of 8.2 km,which is on the same level with that of GPS.For the combined BDS and GPS,the fixed rate and reliability of single-epoch AR and the positioning accuracy are improved significantly.The accuracy of BDS/GPS carrier phase differential positioning is about 35 and 20%better than that of GPS for two short baseline tests in this study.The accuracy of BDS code differential positioning is better than 2.5 m.However it is worse than that of GPS,which may result from large code multipath errors of BDS GEO satellite measurements.YANG YuanXi LI JinLong WANG AiBing XU JunYi HE HaiBo GUO HaiRong SHEN JunFei DAI Xian 2014Science China Earth Sciences2014,57,1:125
3Developing plate tectonics theory from oceanic subduction zones to collisional orogens显示文摘Crustal subduction and continental collision is the core of plate tectonics theory. Understanding the formation and evolution of continental collision orogens is a key to develop the theory of plate tectonics. Different types of subduction zones have been categorized based on the nature of subducted crust. Two types of collisional orogens, i.e. arc-continent and continent-continent collisional orogens, have been recognized based on the nature of collisional blocks and the composition of derivative rocks. Arc-continent collisional orogens contain both ancient and juvenile crustal rocks, and reworking of those rocks at the post-collisional stage generates magmatic rocks with different geochemical compositions. If an orogen is built by collision between two relatively old continental blocks, post-collisional magmatic rocks are only derived from reworking of the old crustal rocks. Collisional orogens undergo reactivation and reworking at action of lithosphere extension, with inheritance not only in the tectonic regime but also in the geochemical compositions of reworked products(i.e., magmatic rocks). In order to unravel basic principles for the evolution of continental tectonics at the post-collisional stages, it is necessary to investigate the reworking of orogenic belts in the post-collisional regime, to recognize physicochemical differences in deep continental collision zones, and to understand petrogenetic links between the nature of subducted crust and post-collisional magmatic rocks. Afterwards we are in a position to build the systematics of continental tectonics and thus to develop the plate tectonics theory.ZHENG YongFei CHEN YiXiang DAI LiQun ZHAO ZiFu 2015Science China Earth Sciences2015,58,7:83
4Ythdc2 is an N^6-methyladenosine binding protein that regulates mammalian spermatogenesis显示文摘N 6-methyladenosine (m 6 一) 是在真核细胞的 mRNA 的最普通的内部修正。它动态地被安装并且搬迁,并且充当 mRNA 新陈代谢,包括干细胞 pluripotency 的调整生物过程,房间区别,和精力动态平衡的新层。m 6 A 被选择有约束力的蛋白质认出;YTHDF1 和 YTHDF3 在音乐会工作影响 m 6包含 A 的 mRNAs, YTHDF2 帮助 mRNA 腐烂,和 YTHDC1 影响它的目标的原子处理。YTHDC2 的生物功能, YTH 蛋白质家庭,的最后的成员仍然保持未知。我们报导 YTHDC2 有选择地绑 m 6 在它的一致主题的 A。YTHDC2 提高它的目标的翻译效率并且也减少他们的 mRNA 丰富。Ythdc2 猛烈老鼠是不肥沃的;男性们让显著地更小的睾丸和女性同窝出生的人与那些相比有显著地更小的卵巢。Ythdc2 猛烈老鼠的细菌房间不经过 zygotene 阶段发展,因此,当成熟分裂开始, Ythdc2 是在睾丸的 upregulated。因此, YTHDC2 是 m 6 在精子发生期间起关键作用的 A 绑定蛋白质。Phillip J Hsu Yunfei Zhu Honghui Ma Yueshuai Guo Xiaodan Shi Yuanyuan Liu Meijie Qi Zhike Lu Hailing Shi Jianying Wang Yiwei Cheng Guanzheng Luo Qing Dai Mingxi Liu Xuejiang Guo Jiahao Sha Bin Shen Chuan He 2017Cell Research2017,27,9:96
5Pre-trained models for natural language processing: A survey显示文摘Recently, the emergence of pre-trained models(PTMs) has brought natural language processing(NLP) to a new era. In this survey, we provide a comprehensive review of PTMs for NLP. We first briefly introduce language representation learning and its research progress. Then we systematically categorize existing PTMs based on a taxonomy from four different perspectives. Next,we describe how to adapt the knowledge of PTMs to downstream tasks. Finally, we outline some potential directions of PTMs for future research. This survey is purposed to be a hands-on guide for understanding, using, and developing PTMs for various NLP tasks.QIU XiPeng SUN TianXiang XU YiGe SHAO YunFan DAI Ning HUANG XuanJing 2020Science China(Technological Sciences)2020,63,10:109
6Nano-Graphene Oxide for Cellular Imaging and Drug Delivery显示文摘Two-dimensional graphene offers interesting electronic,thermal,and mechanical properties that are currently being explored for advanced electronics,membranes,and composites.Here we synthesize and explore the biological applications of nano-graphene oxide(NGO),i.e.,single-layer graphene oxide sheets down to a few nanometers in lateral width.We develop functionalization chemistry in order to impart solubility and compatibility of NGO in biological environments.We obtain size separated pegylated NGO sheets that are soluble in buffers and serum without agglomeration.The NGO sheets are found to be photoluminescent in the visible and infrared regions.The intrinsic photoluminescence(PL)of NGO is used for live cell imaging in the near-infrared(NIR)with little background.We found that simple physisorption viaπ-stacking can be used for loading doxorubicin,a widely used cancer drug onto NGO functionalized with antibody for selective killing of cancer cells in vitro.Owing to its small size,intrinsic optical properties,large specifi c surface area,low cost,and useful non-covalent interactions with aromatic drug molecules,NGO is a promising new material for biological and medical applications.Xiaoming Sun Zhuang Liu Kevin Welsher Joshua Tucker Robinson Andrew Goodwin Sasa Zaric Hongjie Dai 2008Nano Research2008,1,3:118
7Resource diversity of Chinese macrofungi:edible,medicinal and poisonous species显示文摘The huge land areas in China provide highly diverse habitats for macrofungi.Of these macrofungi,many are directly related to people’s daily life and have been utilized by ancient Chinese for at least 6800 years.In this study,we evaluate the current known resource diversity of Chinese macrofungi.A total of 1662 taxa are summarized,and all species names and their authorities have been checked and corrected according to authentic mycological databases.Among the 1662 taxa,1020,692,and 480 are considered to be edible,medicinal and poisonous mushrooms,respectively.A few of edible macrofungi in China are commonly used for commercial production.All known medicinal functions are labeled for medicinal species.The most common medicinal functions possessed by Chinese macrofungi are antitumor or anticancer,followed by antioxidant and antimicrobial.A total of 277 Chinese macrofungi are edible simultaneously with certain medicinal functions and without known toxicity.These species could be treated as“Gold Mushrooms”.Contrarily,193 edible and/or medicinal species are also recognized as poisonous mushrooms.To avoid poisoning caused by these species,ingestion either in a proper way or in small amounts is important.However,the mycotoxins metabolized by these poisonous species could be a huge wealth of natural products yet to be explored.How to utilize these Chinese macrofungal resources is a critical to benefit humans worldwide.Fang Wu Li-Wei Zhou Zhu-Liang Yang Tolgor Bau Tai-Hui Li Yu-Cheng Dai 2019Fungal Diversity2019,,5:81
8Endoscopic variceal ligation compared with endoscopic injection sclerotherapy for treatment of esophageal variceal hemorrhage:A meta-analysis显示文摘AIM:To compare the effect of endoscopic variceal ligation(EVL)with that of endoscopic injection sclerotherapy(EIS)in the treatment of patients withesophageal variceal bleeding.METHODS:We performed a systematic literature search of multiple online electronic databases.Metaanalysis was conducted to evaluate risk ratio(RR)and95%confidence interval(CI)of combined studies for the treatment of patients with esophageal variceal bleeding between EVL and EIS.RESULTS:Fourteen studies comprising 1236 patients were included in the meta-analysis.The rebleeding rate in actively bleeding varices patients in the EVL group was significantly lower than that in the EIS group(RR=0.68,95%CI:0.57-0.81).The variceal eradication rate in actively bleeding varices patients in the EVL group was significantly higher than that in the EIS group(RR=1.06,95%CI:1.01-1.12).There was no significant difference about mortality rate between the EVL group and EIS group(RR=0.95,95%CI:0.77-1.17).The rate of complications in actively bleeding varices patients in the EVL group was significantly lower than that in the EIS group(RR=0.28,95%CI:0.13-0.58).CONCLUSION:Our meta-analysis has found that EVL is better than EIS in terms of the lower rates of rebleeding,complications,and the higher rate of variceal eradication.Therefore,EVL is the first choice for esophageal variceal bleeding.Cong Dai Wei-Xin Liu Min Jiang Ming-Jun Sun 2015World Journal of Gastroenterology2015,21,8:89
9Prevalence of fatty liver disease and the economy in China: A systematic review显示文摘AIM: To investigate the relationship between the economy and the adult prevalence of fatty liver disease(FLD) in China's Mainland. METHODS: Literature searches on the Pub Med and Chinese National Knowledge Infrastructure databases were performed to identify eligible studies published before July 2014. Records were limited to crosssectional surveys or baseline surveys of longitudinal studies that reported the adult prevalence of FLD and recruited subjects from the general population or community. The gross domestic product(GDP) per capita was chosen to assess the economic status. Multiple linear regression and Loess regression were chosen to fit the data and calculate the 95%CIs. Fitting and overfitting of the models were considered in choosing the appropriate models. RESULTS: There were 27 population-based surveys from 26 articles included in this study. The pooled mean prevalence of FLD in China was 16.73%(95%CI: 13.92%-19.53%). The prevalence of FLD was correlated with the GDP per capita and survey years in the country(adjusted R2 = 0.8736, P GDP per capita = 0.00426, P years = 0.0000394), as well as in coastal areas(R2 = 0.9196, P GDP per capita = 0.00241, P years = 0.00281). Furthermore, males [19.28%(95%CI: 15.68%-22.88%)] presented a higher prevalence than females [14.1%(95%CI: 11.42%-16.61%), P = 0.0071], especially in coastal areas [21.82(95%CI: 17.94%-25.71%) vs 17.01%(95%CI: 14.30%-19.89%), P = 0.0157]. Finally, the prevalence was predicted to reach 20.21% in 2020, increasing at a rate of 0.594% per year. CONCLUSION: This study reveals a correlation between the economy and the prevalence of FLD in China's Mainland.Jin-Zhou Zhu Qin-Yi Zhou Yu-Ming Wang Yi-Ning Dai Jiang Zhu Chao-Hui Yu You-Ming Li 2015World Journal of Gastroenterology2015,21,18:116
10METAMORPHIC MECHANISMSAND THEIR CONFIGURATION MODELS显示文摘The concept of metamorphic mechanisms is presented, configuration models and configuration transformations relating to a set of new matrix operations are discussed and proposed. The configuration of a metamorphic mechanism reflects the connectivity change in the mechanism during motions which results in mobility change and presents the characteristics of the mechanism which is discussed in various applications particularly in decorative artifacts. The characteristics is further investigated with mobility analysis.Dai Jiansheng (Department of Mechanical Engineering, School of Physical Sciences and Engineering, King’s College, University of London,Strand,London WC2R 2LS, United kingdom) Zhang Qixian (Robotics Research Institute,Beijing University of Aeronautics and 2000Chinese Journal of Mechanical Engineering2000,13,3:61
11Magnetostratigraphy of the late Cenozoic Laojunmiao anticline in the northern Qilian Mountains and its implications for the northern Tibetan Plateau uplift显示文摘Cenozoic sediments in the foreland basin--Jiuquan Basin in west Hexi Corridor recorded tectonic uplift information of the Qilian Mountains. High resolution paleomagnetic dating of the Laojunmiao (LJM) section across the central LJM anticline in the southern Jiuquan Basin reveals ages of the Getanggou Member, Niugetao Member in the Shulehe Formation, the Yumen Conglomerate, Jiuquan Conglomerate and Gobi Formation at >13-8.3 Ma, 8.3-4.9 Ma, 3.66-0.93 Ma, 0.84-0.14 Ma and 0.14-0 Ma, respectively. Sedimentary evolution study suggests that the Qilian Mountains should begin to rise gradually since ~8-6.6 Ma, accompanied by sedimentary environments changing from lacustrine mudstones-sandstones to alluvial conglomerates. Rapid uplift of the Qilian Mountains began at ~3.66 Ma, followed by a series of stepwise or intermittent intensive uplifts at about <1.8-1.23 Ma, 0.93-0.84 Ma and 0.14 Ma, which finally resulted in the present high Qilian Mountains.FANG Xiaomin1,2, ZHAO Zhijun3,2, LI Jijun2, YAN Maodu2, PAN Baotian2, SONG Chunhui2 & DAI Shuang2 1. Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China 2. Key Laboratory of Western China’s Environmental Systems, Ministry of Education & College of Resources and Environment, Lanzhou University, Lanzhou 730000, China 3. College of Geography, Nanjing Normal University, Nanjing 210097, China 2005Science China Earth Sciences2005,48,7:61
12^(40)Ar-^(39)Ar Isotopic Dating of the Xianghualing Sn-polymetallic Orefield in Southern Hunan,China and Its Geological Implications显示文摘摘要:在湖南省的 Xianghualing Sn-polymetallic orefield,南部的中国,是大尺寸的听 orefield。尽管众多的研究在这 orefield 上被承担了,它的开始,矿化作用年龄,和构造背景仍然是争论的,主要因为听矿化作用上的可靠 geochronological 数据的缺乏。40Ar/39 Ar 标明日期方法的逐步的加热首先在这 orefield 从不同存款在白云母上被采用。从 Xianghualing Sn-polymetallic 存款的白云母样品定义 154.4YUAN Shunda PENG Jiantang SHEN Nengping HU Ruizhong DAI Tongmo 2007Acta Geologica Sinica(English Edition)2007,81,2:76
13Enhanced efficiency of generating induced pluripotent stem (iPS) cells from human somatic cells by a combination of six transcription factors显示文摘Jing Liao Zhao Wu Ying Wang Lu Cheng Chun Cui Yuan Gao Taotao Chen Lingjun Rao Siye Chen Nannan Jia Huiming Dai Shunmei Xin Jiuhong Kang Gang Pei Lei Xiao 2008Cell Research2008,18,5:61
14A nationwide survey of diabetes education, self-management and glycemic control in patients with type 2 diabetes in China显示文摘GUO Xiao-hui YUAN Li LOU Qing-qing SHEN Li SUN Zi-lin ZHAO Fang DAI Xia HUANG Jin YANG Hui-ying 2012Chinese Medical Journal2012,,23:74
15A mini review of NiFe-based materials as highly active oxygen evolution reaction electrocatalysts显示文摘当重要反应在水切开和可充电的金属空气电池包含了,氧进化反应(OER ) 电解为干净精力产生和有效精力存储吸引了增加的注意。镍 / 铁(NiFe ) 基于混合物自从最后世纪,和更新的兴趣在为更好的活动和稳定性开发先进基于 NiFe 的材料上在最近的年里被见证,作为活跃 OER 催化剂被知道了。在这评论,我们在场基于 NiFe 的 OER electrocatalysts 上的早发现和最近的进步以化学性质,合成方法论和催化表演。基于 NiFe 的混合物的每个班的优点和劣势被总结,包括 NiFe 合金, electrodeposited 电影和分层的双氢氧化物 nanoplates。基于 NiFe 的混合物的活跃阶段的一些机械学的研究被介绍并且讨论了给卓见进活跃催化地点的性质,它能便于进一步改善的 NiFe 基于的 OER electrocatalysts。最后,为 OER 的基于 NiFe 的混合物的一些应用程序被描述,包括与有在 1.5 V 和高效下面的电压的一节单个 AAA 电池操作可充电的 Zn 空气电池的 electrolyzer 的开发。Ming Gong Hongjie Dai 2015Nano Research2015,8,1:77
16Chimeric antigen receptor-modified T cells for the immunotherapy of patients with EGFR-expressing advanced relapsed/refractory non-small cell lung cancer显示文摘The successes achieved by chimeric antigen receptor-modified T(CAR-T) cells in hematological malignancies raised the possibility of their use in non-small lung cancer(NSCLC). In this phase I clinical study(NCT01869166), patients with epidermal growth factor receptor(EGFR)-positive(>50% expression), relapsed/refractory NSCLC received escalating doses of EGFR-targeted CAR-T cell infusions. The EGFR-targeted CAR-T cells were generated from peripheral blood after a 10 to 13-day in vitro expansion. Serum cytokines in peripheral blood and copy numbers of CAR-EGFR transgene in peripheral blood and in tissue biopsy were monitored periodically. Clinical responses were evaluated with RECIST1.1 and immune-related response criteria, and adverse events were graded with CTCAE 4.0. The EGFR-targeted CAR-T cell infusions were well-tolerated without severe toxicity. Of 11 evaluable patients, two patients obtained partial response and five had stable disease for two to eight months. The median dose of transfused CAR+ T cells was 0.97×10~7 cells kg^(-1)(interquartile range(IQR), 0.45 to 1.09×10~7 cells kg^(-1)). Pathological eradication of EGFR positive tumor cells after EGFR-targeted CAR-T cell treatment can be observed in tumor biopsies, along with the CAR-EGFR gene detected in tumor-infiltrating T cells in all four biopsied patients. The EGFR-targeted CAR-T cell therapy is safe and feasible for EGFR-positive advanced relapsed/refractory NSCLC.Kaichao Feng Yelei Guo Hanren Dai Yao Wang Xiang Li Hejin Jia Weidong Han 2016Science China(Life Sciences)2016,59,5:62
17Isotopic evidence of TSR origin for natural gas bearing high H_2S contents within the Feixianguan Formation of the northeastern Sichuan Basin, southwestern China显示文摘The northeastern area of Sichuan Basin, southwestern China, is the area with the maximal reserve of natural gas containing higher hydrogen sulphide (H2S) that has been found among the petroliferous basins of China, with the proven and controlled gas reserve of more than 200 billion cubic meters. These gas pools, with higher H2S contents averaging 9%, some 17%, are mainly distributed on structural belts of Dukouhe, Tieshanpo, Luojiazhai, Puguang, etc., while the oolitic-shoal dolomite of the Triassic Feixianguan Fm. (T1f) is the reservoir. Although many scholars regard the plentiful accumulation of H2S within the deep carbonate reservoir as the re-sult of Thermochemical Sulfate Reduction (TSR), however, the process of TSR as well as its residual geological and geochemical evidence is still not quite clear. Based on the carbon iso-topic analysis of carbonate strata and secondary calcite, etc., together with the analysis of sulfur isotopes within H2S, sulphur, gypsum, iron pyrites, etc., as well as other aspects including the natural gas composition, carbon isotopes of hydrocarbons reservoir petrology, etc., it has been proved that the above natural gas is a product of TSR. The H2S, sulphur and calcite result from the participation of TSR reactions by hydrocarbon gas. During the process for hydrocarbons be-ing consumed due to TSR, the carbons within the hydrocarbon gas participate in the reactions and finally are transferred into the secondary calcite, and become the carbon source of secon-dary calcite, consequently causing the carbon isotopes of the secondary calcite to be lower (?18.2‰). As for both the intermediate product of TSR, i.e. sulfur, and its final products, i.e. H2S and iron pyrites, their sulfur elements are all sourced from the sulfate within the Feixianguan Fm. During the fractional processes of sulfur isotopes, the bond energy leads to the 32S being re-leased firstly, and the earlier it is released, the lower δ 34S values for the generated sulphide (H2S) or sulfur will be. However, for the anhydrite that participates in reactions, the higher the reaction degree, the more 32S is released, while the less 32S remains and the more δ 34S is increased. The testing results have proved the process of the dynamic fractionation of sulfur isotopes.ZHU Guangyou ZHANG Shuichang LIANG Yingbo DAI Jinxing LI Jian 2005Science China Earth Sciences2005,48,11:58
18Relationship between hyperuricemia and metabolic syndrome显示文摘Objective: To investigate the relationship between metabolic syndrome and hyperuricemia. Methods: A total of 2 374 subjects who received health examination in our hospital from Jan. 2004 to Dec. 2006 were enrolled in our study. Hyperuricemia is defined as ≥7 mg/dl (in men) or ≥6.0 mg/dl (in women). Metabolic syndrome was defined using AHA/NHLBI (American Heart Association/National Heart, Lung, and Blood Institute) criteria. Results: (1) The overall prevalence of hyperuricemia was 13.10%. The condition was more common in men than in women (19.07% vs 3.42%). (2) Among men, uric acid concentration is statistically significantly positively correlated with waist circumference, blood pressure, and triglyceride. Uric acid is negatively correlated with serum high-density lipoprotein-cholesterol (HDL-C). Uric acid concentration is most strongly correlated with serum triglyceride (r=0.379) and waist circumference (r=0.297). Among women, statistically significant positive correlations were noted for the serum uric acid concentrations with waist circumference, triglyceride and fasting plasma glucose. Serum triglyceride (r=0.329) and waist circumference (r=0.234) are most strongly correlated with uric acid concentrations. (3) Men with hyperuricemia had a 1.634-fold increased risk of metabolic syndrome as compared with those without hyperuricemia odds ratio (OR)=1.634, P=0.000. Women with hyperuricemia had a 1.626-fold increased risk of metabolic syndrome (OR=1.626, P=0.000) as compared with those without hyperuricemia. Conclusion: Hyperuricemia is prevalent among Chinese population. Additionally, serum uric acid is positively associated with metabolic syndrome.CHEN Li-ying ZHU Wen-hua CHEN Zhou-wen DAI Hong-lei REN Jing-jing CHEN Jian-hua CHEN Lei-qian FANG Li-zheng 2007Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)2007,8,8:54
19Determining factors in potential evapotranspiration changes over China in the period 1971-2008显示文摘Potential evapotranspiration(ETo) is important to hydrological cycling and the global energy balance.Based on a modified FAO56-Penman-Monteith model,ETo was simulated for 603 meteorological stations across China in the period 1971-2008.Spatial distribution and temporal change of ETo were characterized,and the determining factors in ETo were revealed by sensitivity analysis.Results show obvious regional differences in annual average ETo and its determining factor.In general,annual average ETo decreased in the period 1971-2008,but increased since the 1990s.Wind speed and sunshine duration were determining factors in the annual ETo trend,with smaller contributions from relative humidity and temperature.Declining wind speed was the determining factor in decreasing annual ETo in northern temperate regions and the Tibetan Plateau.The spatial extent of wind speed influence contracted to northwest China in summer,and expanded to the whole country in autumn.Decreasing sunshine duration was the determining factor in decreasing annual ETo in subtropical and tropical regions,especially in summer,with a larger spatial influence mainly to the southeast of the farming-pastoral region.ETo change has distinct impacts on earth surface ecosystems and environment depending on different determining factors.YIN YunHe WU ShaoHong DAI ErFu 2010Chinese Science Bulletin2010,55,29:53
20Persistence and clearance of viral RNA in 2019 novel coronavirus disease rehabilitation patients显示文摘Background:A patient’s infectivity is determined by the presence of the virus in different body fluids,secretions,and excreta.The persistence and clearance of viral RNA from different specimens of patients with 2019 novel coronavirus disease(COVID-19)remain unclear.This study analyzed the clearance time and factors influencing 2019 novel coronavirus(2019-nCoV)RNA in different samples from patients with COVID-19,providing further evidence to improve the management of patients during convalescence.Methods:The clinical data and laboratory test results of convalescent patients with COVID-19 who were admitted to from January 20,2020 to February 10,2020 were collected retrospectively.The reverse transcription polymerase chain reaction(RT-PCR)results for patients’oropharyngeal swab,stool,urine,and serum samples were collected and analyzed.Convalescent patients refer to recovered non-febrile patients without respiratory symptoms who had two successive(minimum 24 h sampling interval)negative RT-PCR results for viral RNA from oropharyngeal swabs.The effects of cluster of differentiation 4(CD4)+T lymphocytes,inflammatory indicators,and glucocorticoid treatment on viral nucleic acid clearance were analyzed.Results:In the 292 confirmed cases,66 patients recovered after treatment and were included in our study.In total,28(42.4%)women and 38 men(57.6%)with a median age of 44.0(34.0-62.0)years were analyzed.After in-hospital treatment,patients’inflammatory indicators decreased with improved clinical condition.The median time from the onset of symptoms to first negative RT-PCR results for oropharyngeal swabs in convalescent patients was 9.5(6.0-11.0)days.By February 10,2020,11 convalescent patients(16.7%)still tested positive for viral RNA from stool specimens and the other 55 patients’stool specimens were negative for 2019-nCoV following a median duration of 11.0(9.0-16.0)days after symptom onset.Among these 55 patients,43 had a longer duration until stool specimens were negative for viral RNA than for throat swabs,with a median delay of 2.0(1.0-4.0)days.Results for only four(6.9%)urine samples were positive for viral nucleic acid out of 58 cases;viral RNA was still present in three patients’urine specimens after throat swabs were negative.Using a multiple linear regression model(F=2.669,P=0.044,and adjusted R2=0.122),the analysis showed that the CD4+T lymphocyte count may help predict the duration of viral RNA detection in patients’stools(t=-2.699,P=0.010).The duration of viral RNA detection from oropharyngeal swabs and fecal samples in the glucocorticoid treatment group was longer than that in the non-glucocorticoid treatment group(15 days vs.8.0 days,respectively;t=2.550,P=0.013)and the duration of viral RNA detection in fecal samples in the glucocorticoid treatment group was longer than that in the non-glucocorticoid treatment group(20 days vs.11 days,respectively;t=4.631,P<0.001).There was no statistically significant difference in inflammatory indicators between patients with positive fecal viral RNA test results and those with negative results(P>0.05).Conclusions:In brief,as the clearance of viral RNA in patients’stools was delayed compared to that in oropharyngeal swabs,it is important to identify viral RNA in feces during convalescence.Because of the delayed clearance of viral RNA in the glucocorticoid treatment group,glucocorticoids are not recommended in the treatment of COVID-19,especially for mild disease.The duration of RNA detection may relate to host cell immunity.Yun Ling Shui-Bao Xu Yi-Xiao Lin Di Tian Zhao-Qin Zhu Fa-Hui Dai Fan Wu Zhi-Gang Song Wei Huang Jun Chen Bi-Jie Hu Sheng Wang En-Qiang Mao Lei Zhu Wen-Hong Zhang Hong-Zhou Lu 2020Chinese Medical Journal2020,,9:58
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