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Bifurcations of limit Cycles in a Z_4-Equivariant Quintic Planar Vector Field

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Acta Mathematica Sinica,English Series 2010年第4期26卷 779-798页

作者： Yu Hai WU Xue Di wang li xin TIAN Department of Mathematics Jiangsu University Zhenjiang 212013 P. R. China

In this paper, a Z4-equivariant quintic planar vector field is studied. The Hopf bifurcation method and polycycle bifurcation method are combined to study the limit cycles bifurcated from the compounded cycle with 4 hyperbolic saddle points. It is found that this special quintic planar polynomial system has at least four large limit cycles which surround all singular points. By applying the double homoclinic loops bifurcation method and Hopf bifurcation method, we conclude that 28 limit cycles with two different configurations exist in this special planar polynomial system. The results acquired in this paper are useful for studying the weakened 16th Hilbert＇s Problem.

关键词： compounded cycle double homoclinic loops stability bifurcation limit cycles distribution of limit cycles

Synthesis and Biological Activity of Novel 2,3-Dihydro-2-phenylsulfonylhydrazono-3-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyl)thiazoles

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Chemical Research in Chinese Universities 2009年第1期25卷 52-55页

作者： wang Hao-an li Yu-xin li Zheng-ming CHENG Hai-ying wang Su-hua liU Bin Elemento-Organic Chemistry Institute State Key Laboratory of Elemento-Organic Chemistry National Pesticide Engineering Research Center Nankai University Tianjin 300071 P. R. China

A series of novel 2,3-dihydro-2-phenylsulfonylhydrazono-3-（2＇,3＇,4＇,6＇-tetra-O-acetyl-β-D-glucopyranosyl）thiazoles were designed and synthesized via the reaction of thiosemicarbazide with chloroaldehyde. Their chemical structures were characterized by ^1H and ^13C NMR spectroscopy and elemental analysis. The bioassay results indicate that some of these compounds exhibit moderate fungicidal and herbicidal activities.

关键词： Synthesis 2,3-Dihydrothiazole Biological activity

A simulation study of rapid solidification and crystal configuration of Cu_(70)Ni_(30) alloy

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Science China(Physics,Mechanics & Astronomy) 2005年第6期48卷 687-694页

作者： ZHENG Caixing liU Rangsu ZHOU Qunyi TIAN Ze'an wang xin li Qiang Department of Physics Hunan University Changsha 410082 China Department of Physics Hunan University Changsha 410082 China Department of Physics Hunan University Changsha 410082 China Department of Physics Hunan University Changsha 410082 China Department of Physics Hunan University Changsha 410082 China Department of Physics Hunan University Changsha 410082 China

A molecular dynamics (MD) simulation study has been performed for the rapid solidification of Cu70Ni30 adopting the quantum Sutton-Chen many-body potentials. By analyzing the bond-types and the relation of atomic average energy versus temperature, it was demonstrated that as cooling rate being 2 × 1012 K/s, the Cu70Ni30 formed fcc crystal structures and freezing point was found. In addition, having analyzed the transformation of microstructures and the detail of crystal growth by using atomic trace and visual method, not only could the formation of binary disordered solid solution be showed, but also the solidification of liquid metals and the crystal growth processes could be further understood.

关键词： quantum Sutton-Chen potentials, molecular dynamics simulation, Cu70Ni30 alloy, rapid solidification.

Expression of BMP Receptors in Porcine Granulosa Cells (GCs) and Their Regulation by Luteinizing Hormone (LH)

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Agricultural Sciences in China 2011年第2期10卷 289-295页

作者： wang Wei ZHANG Hai-yan HE Yu ZHAO Yong-yan wang li li xin-xiu CHEN Xia XU Yin-xue College of Animal Science ＆ Technology Nanjing Agricultural UniversityNanjing 210095P.R.China

Bone morphogenetic proteins（BMPs） play critical roles in follicle growth and *** initiate signaling by assembling BMP receptors and activating Smads,which in turn alter expression of target *** mechanism underlying the regulation of the expression of BMP receptors and Smads during follicle development in pigs is still *** quantitative real-time PCR,the mRNA expression of BMP receptors and Smads in granulosa cells（GC） was *** were obtained from small porcine follicles（SF;3 mm diameter） and dominant follicles（DF;6 mm diameter）;ActR1A and BMPR2 mRNA levels in DF were significantly higher（P0.05） than that in SF,whereas BMPR1B,Smad4 and Smad7 expression tended to decrease（P0.05）.The levels of BMPR1A,ActR2,Smad1,Smad5,and Smad8 mRNA did not differ between DFs and *** investigate the effect of LH on BMP receptors in GC,cells obtained from porcine DFs were cultured in medium supplemented with different doses of luteinizing hormone（LH）.High doses of LH（4 IU mL-1） significantly decreased the concentration of estradiol（E2） and progesterone（P4） in medium and the expression of Cyp19a1（P450 aromatase,P450arom） and Cyp11a1（cholesterol side-chain cleavage enzyme P450,P450scc）,while significantly increased viable cell numbers and up-regulated expression of cyclin dependent kinase-4（CDK4） and cyclin ***,LH had no effect on the expression of BMP receptor ***,the present study indicates that the expression of members of the BMP signaling pathway in porcine GC is regulated during follicle development and the expression of BMP receptors are not regulated by LH in porcine GCs.

关键词： porcine GCs mRNA expression BMP receptors Smads LH E2 P4

Assessment of wheat variety distinctness using SSR markers

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Journal of Integrative Agriculture 2015年第10期14卷 1923-1935页

作者： wang li-xin QIU Jun CHANG li-fang liU li-hua li Hong-bo PANG Bin-shuang ZHAO Chang-ping Beijing Engineering and Technique Research Center for Hybrid Wheat Beijing Academy of Agricultural and Forestry Sciences National Agriculture Technology Extension and Service Center Ministry of Agriculture National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Science Chinese Academy of Agricultural Sciences

Assessment of variety distinctness is important for both the registration and the protection of particular variety. However, the current testing system, which assesses a range of morphological characters of each pair of varieties grown side-by-side, is time-consuming and is not suitable for the assessment of hundreds of samples. The objective of this study was to develop a procedure for the assessment of wheat variety distinctness using simple sequence repeat（SSR） markers. A comparison between the molecular and morphological profile of 797 varieties was made. On the basis of the comparison, pairs of varieties with a genetic similarity value（GSV） ≤90% were deemed to be distinct, accounting for ~85% of varieties assessed in wheat regional trials. For the remaining ~15% of varieties, GSVs between different varieties were 〉90%, among which ~35% were not distinct and the other ~65% were distinct. Therefore, if given a GSV〉90%, the pairs of varieties should be morphologically assessed in the field. To avoid any errors in the assessments, we proposed the elimination of contaminant plants from the sample before comparing the varietal genotypes, scoring of the genotype at each locus with a pair of allele numbers when constructing a molecular profile, and faithfully recording two alleles at a non-homozygous locus. To reduce the workload and cost, a three-grade markers comparison among varieties is suggested. In addition, 80 SSR markers and a technical procedure for assessment of wheat variety distinctness have been proposed. Based on the procedure, the distinctness assessment of ~85% of all wheat varieties is completed in our laboratory annually. Consequently, total field assessment has been reduced considerably.

关键词： wheat variety distinctness assessment SSR markers

Syntheses of novel series benzo [1,5] oxazepin-4-one-based compounds from 1,5-difluoro-2,4-dinitrobenzene

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Chinese Chemical Letters 2008年第9期19卷 1021-1023页

作者： li Qiu wang Qing Shan li xin Pu Wei Wei Nie Xiao Fei Lv Qiu Rong li Yanshan University Qinhuangdao 066004 China

A novel benzo [ 1,5] oxazepin-4-one skeleton compound and its four derivatives were synthesized effectively from 1,5-difluoro- 2,4-dinitrobenzene （DFDNB） under mild conditions. In the process, four intermediates were synthesized by substitutions of the two fluorine atoms and reductions of the meta-dinitro groups in DFDNB respectively. The results showed that the key for synthesizing the intermediates was the substitution of one of the two fluorine atoms in DFDNB by 3-hydroxy butyric acid ethyl ester first, then the other fluorine atom by morpholine, and then the reduction of the meta-dinitro groups in the substitute by HCOONH4 with Pd/C. The products were purified with silica gel column chromatography, and confirmed by HPLC, LC-MS and 1H NMR. They should contribute to construct the molecular libraries for therapeutic applications.

关键词： Syntheses Benzo oxazepin derivatives DFDNB Substitution Reduction

Targeting Foxp3^＋ regulatory T cells-related immunosuppression for cancer immunotherapy

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Chinese Medical Journal 2010年第22期123卷 3334-3342页

作者： FENG li-li wang xin Department of Hematology Provincial Hospital Affiliated to Shandong University Jinan Shandong 250021 China

Objective To review the current research into Foxp3^＋ regulatory T cells （Treg） cell surface molecules, plasticity of Treg cells and mechanisms of Treg cell suppression and to explore the possibilities to interfere in Treg cell suppression of anti-tumor immunity. Data sources A literature search of all English articles was performed on the online electronic PubMed database dated 1995 to 2010. The keywords searched included： CD4^＋CD25^＋Foxp3^＋ regulatory T lymphocytes, cancer, and immunotherapy. After finding relevant articles within these search limits, a manual search was conducted through the references from these articles. Study selection Articles regarding the role of Treg cells in tumor immunity and the utility of Treg cells in tumor immunotherapy. Results The results show that significant numbers of Treg cells are found in many tumors and it has been shown that the number of tumor infiltrating Treg cells correlates with adverse clinic outcomes. Treg cells are emerging as a key component of acquired tolerance to tumors. Conclusions Several mechanisms of immunosuppression can be mediated by Treg cell function. Distinct immunosuppressive molecules expressed by Treg cells or diverse molecules related to Treg induction or migration represent potential drug targets for caner immunotherapy.

关键词： T lymphocytes, regulatory cancer immune tolerance immunotherapy

Effect of interrupted endogenous BMP/Smad signaling on growth and steroidogenesis of porcine granulosa cells

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2010年第9期11卷 719-727页

作者： Wei wang li wang xin-xiu li Xia CHEN Hai-yan ZHANG Yu HE Jing-jing wang Yong-yan ZHAO Bao-le ZHANG Yin-xue XU College of Animal Science and Technology Nanjing Agricultural University Nanjing 210095 China

Bone morphogenetic proteins(BMPs) play a critical role in the growth and steroidogenesis of granulosa cells(GCs).BMP signals act through membrane-bound heteromeric serine/threonine kinase *** ligand binding,BMPs activate intracellular Smad proteins and regulate growth and apoptosis in various cell *** objective of this study was to demonstrate the effects of BMP/Smad signal on growth and steroidogenesis of porcine GCs.A strategy of RNA interference(RNAi)-mediated 'gene silencing' of Smad4,a core molecule mediating the intracellular BMP/Smad signal transduction pathways,was used to interrupt endogenous BMP/Smad *** indicate that Smad4-small interfering RNA(siRNA) caused specific inhibition of Smad4 mRNA and protein expression after *** endogenous BMP/Smad signaling significantly inhibited growth,and induced apoptosis of porcine GCs,while decreasing estradiol *** addition,interrupted BMP/Smad signaling significantly(Plin D2,CDK4,Bcl-2,and *** findings provide new insights into how BMP/Smad signaling regulates the growth and steroidogenesis of porcine GCs.

关键词： Porcine granulosa cells Bone morphogenetic protein(BMP)/Smad Smad4 RNA interference(RNAi) Growth Steroidogenesis

Microstructure Evolution and Dynamic Softening Mechanism of 00Cr22Ni5Mo3N DSS During Hot Compression

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Journal of Iron and Steel Research International 2011年第7期18卷 64-68页

作者： SONG Zhi gang WU Jiu liN Xiu-ji wang li-xin li Guo-ping ZHENG Wen-jie Central Iron and Steel Research Institute Beijing 100081 China Stainless Steel Council China Special Steel Enterprises Association Beijing 100007 China Taiyuan Iron and Steel (Group) Company Ltd Taiyuan 030003 Shanxi China

Through plane strain compression, hot ductility of 00Cr22Ni5Mo3N DSS is studied under plane strain con dition, and the dynamic softening mechanism is investigated through microstructure observation under TEM. The results show that the deformation temperature can markedly influence the peak stress of 00Cr22NiSMo3N specimens. And being different from DSS softening mechanism generally reported, ferrite can be softened through dynamic re eovery and recrystallization, hut austenite can he softened only through dynamic recovery during hot deformation. The unfavourable effect of N on softening capacity of austenite is greater than that of Ni.

关键词： 00Cr22NiSMo3N plane strain dynamic softening mechanism