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Centers and isochronous centers of a class of quasi-analytic switching systems

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Science China Mathematics 2018年第7期61卷 1201-1218页

作者： Feng Li pei yu Yirong Liu yuanyuan Liu School of Mathematics and Statistics Linyi University Department of Applied Mathematics Western University School of Mathematics and Statistics Central South University

In this paper, we study the integrability and linearization of a class of quadratic quasi-analytic switching systems. We improve an existing method to compute the focus values and periodic constants of quasianalytic switching systems. In particular, with our method, we demonstrate that the dynamical behaviors of quasi-analytic switching systems are more complex than those of continuous quasi-analytic systems, by showing the existence of six and seven limit cycles in the neighborhood of the origin and infinity, respectively, in a quadratic quasi-analytic switching system. Moreover, explicit conditions are obtained for classifying the centers and isochronous centers of the system.

关键词： quasi-analytic switching systems Lyapunov constant limit cycle center isochronous center

Effects of elevated CO_2 on sensitivity of six species of algae and interspecific competition of three species of algae

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Journal of Environmental Sciences 2006年第2期18卷 353-358页

作者： yu Juan TANG Xue-xi TIAN Ji-yuan ZHANG pei-yu DONG Shuang-lin Division of Life Science and Technology Ocean University of China Qingdao 266003 China Department of Environmental Science and Engineering Qingdao University Qingdao 266071 China

Effects of elevated CO, （5000 μl/L） on sensitivity comparison of six species of algae and interspecific competition of three species of algae were investigated. The results showed that, the cell densities of six species of algae grown in elevated CO2 significantly increased compared to those in ambient CO2 （360 μl/L）, and with the time prolonged, the increasing extent increased. Therefore, elevated CO2 can promote the growth of six species of algae. However, there were differences in sensitivity between six species of algae. Based on the effects of elevated CO2 on biomass, the sensitive order （from high to low） was Platymanas sp., Platymanas subcordiformis, Nitzschia closterium, Isochrysis golbana Parke 8701, Dunoliella salina, Chlorella sp., on the condition of solitary cultivation. Compared to ambient CO2, elevated CO2 promoted the growth of three species of algae, Platymanas subcordiformis, Nitzschia closterium and Isochrysis galbana Parke 8701 under the condition of mixed cultivation. The sensitivity of the three species to elevated CO2 in mixed cultivation changed a lot compared to the condition of solitary cultivation. When grown in elevated CO2 under the condition of mixed cultivation, the sensitive order from high to low were Nitzschia clostertium, Platymonas subcordiformis; and Isochrysis galbana Parke 8701. However, under the condition of solitary cultivation, the sensitive order in elevated CO2 was Isochrysis galbana Parke 8701, Nitzschia clostertium, Platymonas subcordiformis, from sensitive to less sensitive. On the day 21, the dominant algae, the sub-dominant algae and inferior algae grown in elevated CO2 did not change. However, the population increasing dynamic and composition proportion of three algal species have significantly changed.

关键词： elevated CO2 microalgae sensitivity interspecific competition

The Second Decadal Leading Mode of East Asian Summer Monsoon Rainfall

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Atmospheric and Oceanic Science Letters 2014年第5期7卷 417-421页

作者： BAO Qing yu pei The State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

The first decadal leading mode of East Asian summer rainfall(EASR) is characterized by rainfall anomalies along the East Asian subtropical rain belt. This study focuses on the second decadal leading mode(2DLM), accounting for 17.3% of rainfall decadal variance, as distinct from the other two neighboring modes of EAMR, based on the state-of-the-art in-situ rainfall *** mode is characterized by a South-China-wet–HuaiheRiver-dry pattern, and is dominated by a quasi-30-yr period. Further analysis reveals the 2DLM corresponds to an enhanced lower-level monsoon jet, an eastward extension of the western North Pacific subtropical high, and a weakened East Asian upper-level westerly jet flow. The Tibetan Plateau surface temperature and Pacific Decadal Oscillation(PDO) are closely linked with the 2DLM. The regressed SST pattern indicates the PDO-like pattern of sea surface temperature anomalies may have a teleconnection relationship with the 2DLM of EASR.

关键词： decadal leading mode East Asian summermonsoon Tibetan Plateau Pacific Decadal Oscillation

Epitaxial growth of Fe/Ag single crystal superlattices and their magnetic properties

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International Journal of Minerals,Metallurgy and Materials 2009年第1期16卷 71-76页

作者： yu Gu Fei Zeng Fang Lv yu-li Gu pei-yong Yang Feng Pan Laboratory of Advanced Materials Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

Single crystal Fe/Ag（001） superlattices with various periodicities were fabricated using ultrahigh vacuum evaporation deposition. It was found that single crystal bcc Fe layers and single crystal fcc Ag layers can epitaxially grow on a single crystal Ag buffer layer alternately, which was deposited on NaCl single crystal chips by ion beam assisted deposition. The magnetic measurements of the superlattices reveal an oscillation coupling between ferromagnetism and antiferromagnetism as a function of the Ag layer thickness. The oscillation period, which is 1 nm （5 Ag layers）, is in good agreement with the calculated values when the Ag thickness is greater than 1.5 nm. While the thickness of the Ag spacer layer decreases to 1 nm, the oscillation coupling varies from calculations, which can be attributed to the intermixing of the interlayers according to the annealing results.

关键词： Fe/Ag superlattices magnetization oscillating periodicity annealing

The Social Responsibility of Chinese Scholars of World History： Zhongguo Shehui Kexue and the Study of World History in the New Era

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Social Sciences in China 2011年第3期32卷 38-46页

作者： yu pei Institute of World History CASS

Modem Chinese study of world history began in the middle of the nineteenth century and was closely related to the main theme of the times, that of saving the nation from subjugation and ensuring its survival. Its chief feature was that it was attuned to the pulse of the times; in all historical periods, the main current of its research has never deviated from the main theme of the times, showing a strong sense of responsibility to society. Under the new historical conditions of reform and opening up, this sense of social responsibility should be reflected in fundamental adherence to the direction of serving the people and socialism.

关键词： study of world history in China Chinese historiography Zhongguo ShehuiKexue

口服太子参多糖对鸡毒支原体弱毒活疫苗免疫增强作用的研究

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中国预防兽医学报 2024年第5期46卷 522-528页

作者：陈沛予游泽龙廖丽华王全溪福建农林大学中西兽医结合与动物保健福建省高等学校重点实验室福建福州350002 福建省兽医中药与动物保健重点实验室(福建农林大学) 福建福州350002

为研究口服太子参多糖(RPP)对鸡毒支原体(MG)弱毒活疫苗的免疫增强作用,本实验选用SPF鸡90只,随机均分为空白对照组(CK组)、疫苗对照组(MG组)和3种不同剂量RPP组(RPP剂量分别为L组50 mg/kg、M组100 mg/kg和H组200 mg/kg)。除CK组和MG组... 详细信息

为研究口服太子参多糖(RPP)对鸡毒支原体(MG)弱毒活疫苗的免疫增强作用,本实验选用SPF鸡90只,随机均分为空白对照组(CK组)、疫苗对照组(MG组)和3种不同剂量RPP组(RPP剂量分别为L组50 mg/kg、M组100 mg/kg和H组200 mg/kg)。除CK组和MG组外,L组、M组和H组均在接种前1 d~7 d口服适量RPP,第8 d时除CK组外各组鸡均经滴鼻MG弱毒活疫苗30μL(1羽份)。每日称饲料用量并在给药后7 d、21 d时各组随机抽9只鸡称重,计算平均日增重、平均日采食量和料肉比;给药前和给药后7 d、10 d、14 d、21 d时每组分别随机经翅下静脉采集6只鸡血液,采用间接ELISA测定细胞因子含量、抗体效价。给药后7 d、14 d、21 d,各组随机抽3只鸡剖杀无菌采集脾脏,分别测定脾脏指数。结果显示:与CK组、MG组相比,给药后21 d时L、M、H组鸡的平均日增重、平均日采食量均显著升高(P<0.05),L、H组鸡料肉比显著降低(P<0.05),21 d时L、M、H组鸡MG抗体效价均显著升高(P<0.05),并达到有效免疫保护水平。血清中相关细胞因子检测结果显示,在给药后14 d时M、H组IFN-γ、IL-4水平均显著上调(P<0.05),IL-1、IL-6含量均显著下调(P<0.05);给药后14 d、21 d时L、M、H组脾脏指数均显著升高(P<0.05)。分别选CK组、MG组和免疫效果最佳的H组5只鸡,于给药后21 d经滴鼻点眼MG MX-4株菌液,记录各组鸡攻毒后鸡体重、症状,2周后剖杀并采集攻毒后鸡肺脏,进行病变评分。结果显示,CK组鸡日增重显著低于(P<0.05)MG组、H组,而MG组和H组比较,MG组1只鸡日增重低于MG组平均值,其余鸡生长性能均无明显异常;CK组鸡肺脏病变较为严重(病变平均分值为6.8分),MG组鸡肺脏仅轻微病变(病变平均分值为1.8分),H组肺脏无明显病变(病变平均分值为0.6分)。上述结果首次表明,口服RPP能够使免疫MG弱毒活疫苗鸡的抗体效价快速上升,脾脏功能增强,提高鸡的生长性能,并升高Th1型细胞因子IFN-γ和Th2型细胞因子IL-4在鸡血清中的含量,从而促进免疫鸡的细胞免疫反应与抗原提呈能力;另外还可显著降低血清中促炎因子IL-1、IL-6含量,具有一定的抗炎作用;同时可有效降低攻毒鸡肺脏病变程度,减缓MG感染导致鸡的生长性能下降。本研究为RPP在MG弱毒活疫苗免疫中的应用提供了科学参考依据。

关键词：太子参多糖鸡毒支原体鸡免疫功能

乡村振兴背景下“毛南香韵”特色农副产品包装设计

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绿色包装 2024年第3期 70-73页

作者：李辰飞张培瑜桂林理工大学广西桂林541004 桂林旅游学院艺术设计学院广西桂林541006

少数民族文化是中华文化不可或缺的重要组成部分,随着乡村经济的发展,继承少数民族优秀文化成为乡村振兴的有效途径之一。本文提出和分析环江毛南族特色农副产品助力乡村振兴面临的关键问题;基于挖掘毛南族乡村特色文化、建立特色农副... 详细信息

少数民族文化是中华文化不可或缺的重要组成部分,随着乡村经济的发展,继承少数民族优秀文化成为乡村振兴的有效途径之一。本文提出和分析环江毛南族特色农副产品助力乡村振兴面临的关键问题;基于挖掘毛南族乡村特色文化、建立特色农副产品品牌等方面,总结问题的解决方案;展望“毛南香韵”特色农副产品设计发展趋势。

关键词：毛南族农副产品乡村振兴包装设计

Impact of COVID-19 on the clinical status of patients with Wilson disease

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World Journal of Gastroenterology 2021年第26期27卷 4248-4251页

作者： yu-pei Zhuang Hao-Jie Zhong Department of Gastroenterology The First Affiliated Hospital of Guangdong Pharmaceutical UniversityGuangzhou 510080Guangdong ProvinceChina School of Biology and Biological Engineering South China University of TechnologyGuangzhou 510000Guangdong ProvinceChina Institute of Microbiology Guangdong Academy of SciencesGuangzhou 510000Guangdong ProvinceChina

The coronavirus disease 2019(COVID-19)pandemic has greatly impacted health *** guidelines on chronic liver diseases have been released to optimize the use of medical resources and patient ***,most of these guidelines have been established through expert consensus because the existing data do not provide strong evidence for developing effective *** Wilson disease(WD)is a rare chronic liver disease,the impact of COVID-19 on the clinical status of patients with WD is *** present study showed a marked shortage of medical resources for clinically managing patients with WD during the *** patients with WD who consistently took anticopper therapy showed no significant differences in hepatic and extrahepatic markers before and after the pandemic,their complication incidences,especially the infection incidence,were significantly increased during the study ***,patients with WD should be encouraged to adhere to anticopper therapy and be closely monitored to prevent infections and other *** present study provides a clinical basis for further managing WD during the pandemic.

关键词： Coronavirus disease 2019 Wilson disease Clinical status Complications Infections Anticopper therapy

表达Strep-tag II的重组塞内卡病毒的构建与鉴定

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中国预防兽医学报 2024年第2期46卷 140-146页

作者：史家宝蒙靓肖培宇范峻豪安同庆王海伟于力中国农业科学院哈尔滨兽医研究所动物疫病防控全国重点实验室黑龙江哈尔滨150069

为构建表达Strep-tag II的重组塞内卡病毒(SVA),本研究在感染性cDNA克隆p SVA-I212V/S460L的基础上,采用重叠延伸PCR扩增Strep-tag II并采用无缝克隆法将其插入SVA VP1基因C端,构建感染性cDNA克隆,命名为p SVA-Strep,并采用双酶切和测... 详细信息

为构建表达Strep-tag II的重组塞内卡病毒(SVA),本研究在感染性cDNA克隆p SVA-I212V/S460L的基础上,采用重叠延伸PCR扩增Strep-tag II并采用无缝克隆法将其插入SVA VP1基因C端,构建感染性cDNA克隆,命名为p SVA-Strep,并采用双酶切和测序鉴定正确后,将p SVA-Strep转染BHK-21细胞拯救重组病毒,收集病变细胞上清,并将含有病毒的细胞上清和野生型SVA(SVA-WT)分别感染BHK-21细胞,以未感染病毒的BHK-21细胞作为阴性对照,感染后24 h分别以鼠源SVA VP2蛋白单克隆抗体(MAb)5D10(1∶1000)、鼠源Strep-tag II MAb(1∶2000)作为一抗,以FITC标记的山羊抗小鼠Ig G(1∶2000)为二抗,采用间接免疫荧光试验(IFA)对重组病毒鉴定。IFA结果显示,以鼠源SVA VP2蛋白MAb 5D10为一抗,SVA-WT和重组病毒感染的细胞均出现绿色荧光,以Strep-tag II MAb作为一抗时,仅有重组病毒感染的细胞出现绿色荧光,经SVA-WT感染的BHK-21细胞及阴性对照细胞均无绿色荧光,表明拯救了Strep-tag II标记的重组病毒,并将其命名为r SVA-Strep。将r SVA-Strep在BHK-21细胞中连续传10代,每隔2代采用引物VP1-F/R经PCR鉴定并对第10代重组病毒的VP1基因测序以鉴定r SVA-Strep的遗传稳定性。结果显示,每隔两代的重组病毒经PCR扩增后均出现约780 bp的目的条带,第10代重组病毒扩增的VP1基因测序结果显示Strep-tag II基因仍在重组病毒中,且无基因突变,表明r SVA-Strep的遗传稳定性较强;将SVA-WT和r SVA-Strep分别以MOI 0.01感染BHK-21细胞,在感染后4 h、8 h、12 h、24 h、36 h、48 h和72 h收获病毒测定病毒滴度并绘制生长曲线,结果显示在病毒感染36 h内r SVA-Strep和SVA-WT生长动力学基本一致,表明Strep-tag II的引入在病毒感染36 h内对SVA的复制基本无影响。采用0.2%甲醛充分灭活r SVA-Strep,并利用Strep-TactinRXT Purification纯化试剂盒纯化该灭活病毒,将r SVA-Strep灭活病毒上清加至Strep-Tactin亲和层析柱,分别用不同体积洗脱缓冲液依次洗脱病毒并通过western blot鉴定病毒的纯化效果。对纯化过程中不同洗脱液洗脱病毒的western blot结果显示,不同体积的洗脱液中E1、E2和E3均出现VP0和VP2两条带,且E1和E2的条带最明显,表明洗脱缓冲液的最佳洗脱体积约为2.2 CV;以上结果表明r SVA-Strep可通过Strep-Tactin亲和层析柱一步法纯化。本研究在SVA中插入Strep-tag II标签,为SVA灭活疫苗的快速纯化提供技术手段,也为其他病原的快速纯化方法的建立提供参考。

关键词：塞内卡病毒 Strep-tag II 感染性克隆抗原纯化