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Experimental Study on Influencing Factors of Resistance Coefficient and Residual Resistance Coefficient in Oilfield Z 预览
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作者 Xinran Wang Lizhen Ge +2 位作者 Dong Liu Qin Zhu Bin Zheng 《世界工程和技术(英文)》 2019年第2期270-281,共12页
In order to clarify the major influence factors of resistance coefficient and residual resistance coefficient, so as to provide the basis for optimizing the polymer flooding schemes in oilfield Z of Bohai Sea, artific... In order to clarify the major influence factors of resistance coefficient and residual resistance coefficient, so as to provide the basis for optimizing the polymer flooding schemes in oilfield Z of Bohai Sea, artificial cores were made by simulated the characteristic parameters of real reservoir and the spacing of production-injection wells. The main parameters considered include reservoir permeability, polymer solution concentration and polymer injection rate. Core experiment of polymer flooding was taken by considering all the main parameters. The result showed that resistance coefficient and residual resistance coefficient decrease with the increase of core permeability. Resistance coefficient and residual resistance coefficient increase with the increase of concentration of polymer solution. The increment of displacement pressure in low permeability core is higher than in medium and high permeability core. The resistance coefficient increase with higher displacing velocity, and the increment in high permeability core is higher than in low permeability?core. The displacement velocity has little effect on the residual resistance coefficient. The experimental results can effectively guide the formulation of polymer flooding scheme in offshore oilfields, and optimize the appropriate injection rate and concentration of polymer solution for different properties of reservoirs, thus ensuring the effectiveness of polymer flooding in offshore oilfields. 展开更多
关键词 RESISTANCE COEFFICIENT RESIDUAL RESISTANCE COEFFICIENT Polymer FLOODING Laboratory Experiment OFFSHORE OILFIELD
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Quantitative Characterization and Dynamic Law of Interlayer Interference for Multilayer Commingled Production in Heavy Oil Reservoirs by Numerical Simulation 预览
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作者 Dong Liu Fengyi Zhang +2 位作者 Qin Zhu Xinran Wang Jing Fan 《世界工程和技术(英文)》 2019年第3期379-395,共17页
This paper moves one step forward to build?a?numerical model to research quantitative characterization and dynamic law for interlayer interference factor (IIF) in the multilayer reservoir which was heavy oil reservoir... This paper moves one step forward to build?a?numerical model to research quantitative characterization and dynamic law for interlayer interference factor (IIF) in the multilayer reservoir which was heavy oil reservoirs and produced by directional wells. There are mainly four contributions of this paper to the existing body of literature. Firstly, an equivalent simulation method of the pseudo start pressure gradient (PSPG) is developed to quantitatively predict the value of?IIF?under different geological reservoir conditions. Secondly, the interlayer interference is extended in time, and the time period of the study extends from a water cut stage to the whole process from the oil well open to produce?a?high water cut. Thirdly, besides the conventional productivity interlayer interference factor (PIIF), a new parameter, that is, the oil recovery interlayer interference factor (RIIF) is put forward.?RIIF?can be used to evaluate the technical indexes of stratified development and multilayer co-production effectively. Fourthly,?the?effectsof various geological reservoir parameters such as reservoir permeability and crude oil viscosity, etc. on the?PIIF?and?RIIF’s?type curves?are?discussed in detail and the typical plate?is?plotted. The research results provide a foundation for the effective development of multilayer heavy oil reservoirs. 展开更多
关键词 Heavy Oil INTERLAYER Interference MULTILAYER Commingled PRODUCTION PSEUDO START Pressure Gradient Water FLOODING
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Interaction of H2^+ molecular beam with thin layer graphene foils
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作者 李敏 曲国峰 +10 位作者 王亦舟 朱洲森 师勉恭 周茂蕾 刘东 徐子虚 宋明江 张俊 白帆 廖小东 韩纪锋 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第9期164-168,共5页
The interaction of MeV H2^+ molecular ions with thin layer graphene and graphite foils was studied by using a highresolution electrostatic analyzer.A large number of fragment protons were observed at zero degree(along... The interaction of MeV H2^+ molecular ions with thin layer graphene and graphite foils was studied by using a highresolution electrostatic analyzer.A large number of fragment protons were observed at zero degree(along the beam direction) when the H2^+ beam was passing through the monolayer graphene foil, which indicates that the electron of the H2^+ molecular ions can be stripped easily even by the monolayer graphene foil.More trailing than leading protons were found in the energy spectrum, which means significant wake effect was observed in the monolayer graphene foil.The ratio of the numbers of trailing protons over leading protons first increased with the thickness for the much thinner graphene foils, and then decreased with the thickness for the much thicker graphite foils, which indicates that the bending effect of the wake field on the trailing proton varied with the foil thickness. 展开更多
关键词 H2^+ molecular IONS GRAPHENE electron STRIPPING WAKE effect
转炉蒸发冷却器换热效率数值模拟
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作者 李海英 刘东 +2 位作者 张春奇 刘良旭 王晓波 《过程工程学报》 CAS CSCD 北大核心 2019年第3期492-499,共8页
基于国内某钢厂65 t转炉蒸发冷却器运行参数,采用CFD方法的离散相模型模拟了蒸发冷却器内雾化液滴与高温烟气间的换热效率,考察了单个液滴粒径、雾化液滴粒径分布对换热效率的影响。结果表明,模拟结果与实际运行参数吻合较好,计算的出... 基于国内某钢厂65 t转炉蒸发冷却器运行参数,采用CFD方法的离散相模型模拟了蒸发冷却器内雾化液滴与高温烟气间的换热效率,考察了单个液滴粒径、雾化液滴粒径分布对换热效率的影响。结果表明,模拟结果与实际运行参数吻合较好,计算的出口温度为468 K,实际为483 K,相对误差为3.1%,模型可靠。粒径小于300μm的雾滴均能在0.62 s内蒸发完全,不同粒径的雾滴完全蒸发所需时间最高相差20多倍。液滴与高温烟气的换热效率受粒径分布影响较大,中位粒径d50=340μm和d50=95μm的雾滴在同一截面的平均温度可相差70K。烟气温度下降先快后慢,最后趋于平稳,烟气主要降温区域为喷嘴下游3.5 m内。 展开更多
关键词 蒸发冷却器 数值模拟 液滴 蒸发特性 粒径分布
MicroRNA-92a在胰腺癌中的表达及对肿瘤生长的影响 预览
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作者 许勇 李波 +4 位作者 林强 钟昌桃 刘东 程愿 钟云昌 《中国现代医学杂志》 CAS 2019年第3期52-56,共5页
目的探讨人胰腺导管腺癌(PDAC)中microRNA-92a(miR-92a)的表达及对肿瘤细胞生长的影响。方法实时荧光定量聚合酶链反应(qRT-PCR)检测PDAC组织中miR-92a的表达水平;慢病毒转染PANC-1细胞构建miR-92a稳定敲除模型,克隆形成与流式细胞仪检... 目的探讨人胰腺导管腺癌(PDAC)中microRNA-92a(miR-92a)的表达及对肿瘤细胞生长的影响。方法实时荧光定量聚合酶链反应(qRT-PCR)检测PDAC组织中miR-92a的表达水平;慢病毒转染PANC-1细胞构建miR-92a稳定敲除模型,克隆形成与流式细胞仪检测细胞增殖凋亡;通过裸鼠皮下种植瘤模型检测下调miR-92a表达对肿瘤体内生长的影响;PCR及Western blotting检测miR-92a下游靶点DOC-2/DAB2结合蛋白(DAB2IP)在体外培养细胞中的表达水平;免疫组织化学检测DAB2IP在移植瘤组织中的表达水平。结果miR-92a在PDAC组织中表达水平高于癌旁组织(P<0.05);miR-92a高表达的胰PDAC者肿瘤体积较miR-92a低表达者更大(P<0.05);下调miR-92a的表达能够抑制胰腺癌PANC-1细胞体外增殖能力,促进细胞凋亡,并抑制PANC-1细胞裸鼠皮下种植瘤的生长;下调miR-92a表达提高了PANC-1细胞内DAB2IP的表达水平及移植瘤组织内DAB2IP的表达水平(P<0.05)。结论miR-92a在胰腺癌中表达升高,下调miR-92a的表达能使DAB2IP的表达下调而发挥抗肿瘤生长作用。 展开更多
关键词 胰腺肿瘤 MICRORNAS DOC-2/DAB2结合蛋白
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Enhanced soft magnetic properties of iron powders through coating MnZn ferrite by one-step sol–gel synthesis
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作者 刘冬 高善民 +4 位作者 金仁成 王峰 初晓晓 高太平 王玉宝 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第5期300-304,共5页
The MnZn ferrite coating formed on the surface of iron-based soft magnetic powders via facile and modified sol–gel process has been fabricated to obtain better magnetic performance due to its higher permeability comp... The MnZn ferrite coating formed on the surface of iron-based soft magnetic powders via facile and modified sol–gel process has been fabricated to obtain better magnetic performance due to its higher permeability compared with traditional nonmagnetic insulation coatings.The influence of the MnZn ferrite contents on the magnetic performance of the soft magnetic composites (SMCs) has been studied.As the MnZn insulation content increases,the core loss first experiences a decreasing trend that is followed by progressive increase,while the permeability follows an increasing trend and subsequently degrades.The optimized magnetic performance is achieved with 2.0 wt% MnZn ferrite,which results from the decrement of inter-particle eddy current losses based on loss separation.A uniform and compact coating layer composed of MnZn ferrite and oxides with an average thickness of 0.38±0.08 μm is obtained by utilizing ion beam technology,and the interface between the powders and the coating shows satisfied adhesiveness compared with the sample directly prepared by mechanical mixing.The evolution of the coating layers during the calcination process has been presented based on careful analysis of the composition and microstructure. 展开更多
关键词 soft MAGNETIC POWDERS MAGNETIC performance COATING layer ion beam technology
水基石墨烯纳米流体在矩形小槽道内的流动换热特性
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作者 刘东 舒宇 胡安杰 《过程工程学报》 CAS CSCD 北大核心 2019年第2期289-296,共8页
测试了水基石墨烯纳米流体的部分热物性,研究了不同浓度、雷诺数(Re)和加热功率条件下水基石墨烯纳米流体作为换热工质在设计的矩形结构小槽道内的对流换热性能。结果表明,层流状态(Re=500~2000)下,矩形槽道壁面温度随Re增大逐渐降低,... 测试了水基石墨烯纳米流体的部分热物性,研究了不同浓度、雷诺数(Re)和加热功率条件下水基石墨烯纳米流体作为换热工质在设计的矩形结构小槽道内的对流换热性能。结果表明,层流状态(Re=500~2000)下,矩形槽道壁面温度随Re增大逐渐降低,随加热功率增大逐渐升高,与常规流体换热特性一致;在相同Re和换热功率条件下,随纳米流体浓度增大,壁温逐渐减小;水基石墨烯纳米流体的换热强度比基液去离子水提升较大,Re=2000、加热功率为210W时,浓度为0.03wt%的水基石墨烯纳米流体的平均努塞尔数(Nu)为9.3,比基液水提升48.8%;受入口效应影响,沿槽道长度局部对流换热系数逐渐减小,最高可达25674.5 [W/(m2·℃)],较基液水最大可提高39.1%;Re=500~1 400时,石墨烯纳米流体的流动换热强度随Re增大明显增强;由实验数据结合理论模型拟合了适用于石墨烯纳米流体对流换热强度的计算式,计算结果与实验结果最大相对误差不超过25%,平均相对误差仅为4.8%。 展开更多
关键词 石墨烯 纳米粒子 对流 传热 小槽道
New Discovery of the 341 Ma Gabbro at Xiongcun District in the Southern Margin of Lhasa Terrane, Tibet 预览
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作者 LANG Xinghai LIU Dong +9 位作者 DENG Yulin TANG Juxing XIE Fuwei YANG Zongyao CUI Zhiwei WANG Xuhui LI Zhijun ZHANG Zhong ZHANG Jinshu HUANG Yong 《地质学报:英文版》 SCIE CAS CSCD 2018年第1期420-421,共2页
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Leidenfrost drops on micro/nanostructured surfaces
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作者 Vishal TALARI Prakhar BEHAR +2 位作者 Yi LU Evan HARYADI Dong LIU 《能源前沿:英文版》 CSCD 2018年第1期22-42,共21页
处于 Leidenfrost 状态,液体落下被从落下经由蒸发产生的蒸汽层在热稳固的表面上面升在空中。蒸汽层热地绝缘从加热表面的落下,在无数重要工程应用引起败坏的热转移。因此,压制 Leidenfrost 效果并且提高 Leidenfrost 温度是高度合... 处于 Leidenfrost 状态,液体落下被从落下经由蒸发产生的蒸汽层在热稳固的表面上面升在空中。蒸汽层热地绝缘从加热表面的落下,在无数重要工程应用引起败坏的热转移。因此,压制 Leidenfrost 效果并且提高 Leidenfrost 温度是高度合乎需要的。这份报纸在 Leidenfrost 温度的改进上与一个重音在 micro/nanostructured 表面上有关 Leidenfrost 落下论述最近的文学的全面评论。Leidenfrost 效果的基本物理过程和 Leidenfrost 落下的关键特征首先被介绍。然后, Leidenfrost 温度上的各种各样的 micro/nanoscale 表面结构的影响的主要调查结果详细被介绍,并且为各特定的表面拓扑学的内在的改进机制也被讨论。多尺度的层次表面保持最好的诺言显著地由联合两个的优点增加 Leidenfrost 温度,这被结束微 -- 并且 nanoscale 结构。 展开更多
关键词 热表面 表面结构 物理过程 调查结果 温度 热转移 拓扑学 多尺度
黄芩苷治疗原发性肝癌的研究进展 预览 被引量:1
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作者 向东 杨金玉 +1 位作者 张程亮 刘东 《世界华人消化杂志》 CAS 2018年第6期378-383,共6页
原发性肝癌(hepatocellular carcinoma,HCC)是常见恶性肿瘤之一,中医药在治疗HCC领域具有独特的疗效.中药黄芩具有解热保肝之功效,其主要有效活性成分黄芩苷治疗HCC的作用近年来被大量报道.其抑制HCC生长的机制涉及诱导癌细胞凋... 原发性肝癌(hepatocellular carcinoma,HCC)是常见恶性肿瘤之一,中医药在治疗HCC领域具有独特的疗效.中药黄芩具有解热保肝之功效,其主要有效活性成分黄芩苷治疗HCC的作用近年来被大量报道.其抑制HCC生长的机制涉及诱导癌细胞凋亡和分化、抑制蛋白合成、抑制癌细胞迁徙、干扰细胞间通讯和逆转肿瘤耐药等.此外,黄芩苷与传统化疗药物或其他抗癌中药用于治疗HCC也有较好的协同作用.基于黄芩苷的体内吸收特征和分子结构,研究者亦开发出黄芩苷固体脂质纳米粒和黄芩苷金属离子复合物,为黄芩苷的靶向治疗和提高抗癌效果提供了新视角.本文综述了近年来黄芩苷治疗HCC的国内外文献报道,以期为临床和科研工作者提供有价值参考. 展开更多
关键词 原发性肝癌 黄芩苷 凋亡
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超高泵浦功率下的Xe(6p[1/2]0,6p[3/2]2,和6p[5/2]2)原子的能量转移过程 预览
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作者 何山 褚俊植 +9 位作者 刘栋 李学杨 郭敬为 刘金波 胡墅 李慧 王鹏远 陈莹 桑凤亭 金玉奇 《化学物理学报》 SCIE CAS CSCD 2018年第6期741-748,733共9页
本文研究了Xe(6p[1/2]0,6p[3/2]2,and6p[5/2]2)原子在聚焦条件下的动力学过程.激发能级的原子密度在聚焦条件下会显著地增加,因此两个高激发态原子之间的energy-pooling碰撞的概率也会增加.这种energy-pooling碰撞主要有三种类型.第一... 本文研究了Xe(6p[1/2]0,6p[3/2]2,and6p[5/2]2)原子在聚焦条件下的动力学过程.激发能级的原子密度在聚焦条件下会显著地增加,因此两个高激发态原子之间的energy-pooling碰撞的概率也会增加.这种energy-pooling碰撞主要有三种类型.第一种类型为energy-pooling碰撞导致的电离.一旦将激发激光聚焦,就可以从侧面的窗口观察到非常明显的电离现象,不论激发能级是6p[1/2]0、6p[3/2]2或6p[5/2]2能级.这种电离的产生机理是energy-pooling电离或者一个Xe*原子再吸收一个光子产生电离.第二种类型为跨越较大能极差的energy-pooling碰撞.当激发能级为6p[1/2]0能级的情况下,两个6p[1/2]0原子碰撞会产生一个5d[3/2]1原子和一个6s'[1/2]0原子.第三种类型为跨越较小能级差的energy-pooling碰撞.以5个二次产生的6p能级为上能级的荧光强度都变得更强,并且这些荧光的上升沿都变得更陡峭.产生这些6p原子的主要机理是energy-pooling碰撞并非简单的碰撞弛豫.基于理想气体原子之间的碰撞概率公式,推导出两个6p[1/2]0原子的energy-pooling碰撞速率为6.39x10^8s-1.此外,6s原子在聚焦条件下的密度也会增加.因此所有的荧光曲线会因为辐射俘获效应而出现非常严重的拖尾. 展开更多
关键词 能量池碰撞 动力学 超高激发功率
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Mechanical properties and microstructure of 3D-printed high Co–Ni secondary hardening steel fabricated by laser melting deposition 预览
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作者 Hui-ping Duan Xiao Liu +2 位作者 Xian-zhe Ran Jia Li Dong Liu 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2017年第9期1027-1033,共7页
The mechanical properties and microstructure of the 3D-printed high Co–Ni secondary hardening steel fabricated by the laser melting deposition technique was investigated using a material testing machine and electron ... The mechanical properties and microstructure of the 3D-printed high Co–Ni secondary hardening steel fabricated by the laser melting deposition technique was investigated using a material testing machine and electron microscopy. A microstructure investigation revealed that the samples consist of martensite laths, fine dispersed precipitates, and reverted austenite films at the martensite lath boundaries. The precipitates are enriched with Co and Mo. Because the sample tempered at 486°C has smaller precipitates and a higher number of precipitates per unit area, it exhibits better mechanical properties than the sample tempered at 498°C. Although the 3D-printed samples have the same phase constituents as Aer Met 100 steel, the mechanical properties are slightly worse than those of the commercial wrought Aer Met 100 steel because of the presence of voids. 展开更多
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P2Y1R is involved in visceral hypersensitivity in rats with experimental irritable bowel syndrome 预览
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作者 Jie Wu Yan Cheng +5 位作者 Rong Zhang Dong Liu Yu-mei Luo Kun-Lun Chen Song Ren Jun Zhang 《世界胃肠病学杂志:英文版》 SCIE CAS 2017年第34期6339-6349,共11页
AIM To evaluate the role of P2Y1 R in visceral hypersensitivity in rats with experimental irritable bowel syndrome.METHODS A rat model of irritable bowel syndrome was generated by intra-colonic administration of aceti... AIM To evaluate the role of P2Y1 R in visceral hypersensitivity in rats with experimental irritable bowel syndrome.METHODS A rat model of irritable bowel syndrome was generated by intra-colonic administration of acetic acid(AA) and assessed by histology and myeloperoxidase(m PO) activity assay. Then P2Y1 R expression in the colonic tissue was detected by Western blot. In order to explore the regulatory role of P2Y1 R in visceral hypersensitivity, an agonist(m RS2365) and an antagonist(m RS2179) of P2Y1 R were intra-colonically administered and effects were tested through a colorectal distension test. The abdominal withdrawal reflex and abdominal electromyography were tested during the course. RESULTS model assessment tests showed an obvious inflammatoryreaction that appeared on the 2nd d after the AA injection, and the inflammatory reaction gradually recovered and almost disappeared on the 7th d. The model finished on day 8 and showed a clear feature of IBS that had no organic lesion. The average expression of P2Y1 R was significantly higher in the AA group than in the na?ve group(0.319 ± 0.02 vs 0.094 ± 0.016, P < 0.001). m RS2365 could effectively raise the colonic hypersensitivity status at intervention doses of 10(AUC value from 0.30 ± 0.089 to 1.973 ± 0.127 mv?s, P < 0.01) and 100 μmol/L(AUC value from 0.290 ± 0.079 to 1.983 ± 0.195 mv?s, P < 0.01); m RS2179 could effectively reduce the hypersensitivity status at intervention dose of 100 μmol/L(from a mean baseline AUC value of 1.587 ± 0.099 mv?s to 0.140 ± 0.089 mv?s, P < 0.0001). Differences between the m RS2179 group(1.88 ± 1.45) and either the m RS2365 group(3.96 ± 0.19) or the combined treatment(m RS2179 and m RS2365) group(3.28 ± 0.11) were significant(P < 0.01).CONCLUSION P2Y1 R plays a regulatory role in visceral hypersensitivity in rats with experimental IBS. Specific antagonists of P2Y1 R may have potential therapeutic value in treating abdominal pain in IBS. 展开更多
关键词 急躁的肠症候群 P2Y1 受体 规定 治疗 内脏的超敏性
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Ghrelin and gastrointestinal stromal tumors 预览
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作者 Chang-Zhen Zhu Dong Liu +4 位作者 Wei-Ming Kang Jian-Chun Yu Zhi-Qiang Ma Xin Ye Kang Li 《世界胃肠病学杂志:英文版》 SCIE CAS 2017年第10期1758-1763,共6页
Ghrelin, as a kind of multifunctional protein polypeptide, is mainly produced in the fundus of the stomach and can promote occurrence and development of many tumors, including gastrointestinal tumors, which has been p... Ghrelin, as a kind of multifunctional protein polypeptide, is mainly produced in the fundus of the stomach and can promote occurrence and development of many tumors, including gastrointestinal tumors, which has been proved by the relevant researches. Most gastrointestinal stromal tumors(GISTs, about 80%), as the most common mesenchymal tumor, also develop in the fundus. Scientific research has confirmed that ghrelin, its receptors and m RNA respectively can be found in GISTs, which demonstrated the existence of a ghrelin autocrine/paracrine loop in GIST tissues. However, no reports to date have specified the mechanism whether ghrelin can promote the occurrence and development of GISTs. Studies of pulmonary artery endothelial cells in a low-oxygen environment and cardiac muscle cells in an ischemic environment have shown that ghrelin can activate the phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin(PI3K/AKT/m TOR) signaling pathway. Moreover, some studies of GISTs have confirmed that activation of the PI3K/AKT/m TOR pathway can indeed promote the growth and progression of GISTs. Whether ghrelin is involved in the development or progression of GISTs through certain pathways remains unknown. Can we find a new target for the treatment of GISTs? This review explores and summaries the relationship among ghrelin, the PI3K/AKT/m TOR pathway and the development of GISTs. 展开更多
关键词 胃肠的 stromal 肿瘤 PI3K/AKT/mTOR 小径 GHRELIN 出现 开发
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Elevated expression of EBV and TLRs in the brain is associated with Rasmussen's encephalitis
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作者 Xin Wang Yisong Wang +6 位作者 Dong Liu Peigang Wang Dongying Fan Yuguang Guan Tianfu Li Guoming Luan Jing An 《中国病毒学:英文版》 CAS CSCD 2017年第5期423-430,共8页
Rasmussen's encephalitis(RE) is a rare pediatric neurological disorder, the etiology of which remains unclear. It has been speculated that the immunopathogenesis of RE involves damage to neurons, which eventually ... Rasmussen's encephalitis(RE) is a rare pediatric neurological disorder, the etiology of which remains unclear. It has been speculated that the immunopathogenesis of RE involves damage to neurons, which eventually leads to the occurrence of RE. Viral infection may be a critical factor in triggering RE immunopathogenesis. In this study, we analyzed the expression of Epstein-Barr virus(EBV) antigens as well as of Toll-like receptor 3(TLR3), TLR9, and downstream adapter TIRdomain-containing adapter-inducing interferon-β(TRIF) in the brain tissues of 26 patients with RE and 16 control individuals using immunohistochemistry(IHC). In the RE group, EBV antigens were detected in 53% of individuals at various expression levels. In contrast, there was no detectable EBV antigen expression in control brain tissues. Moreover, we found marked increases in the expression of TLR3, TLR9, and TRIF in the brain tissues of RE patients compared with levels in the control group. Furthermore, among RE cases, EBV expression and high TLR3 expression were associated with more severe brain atrophy. Our results suggest that the elevated expression of EBV and TLRs may be involved in RE occurrence through the activation of downstream molecules. 展开更多
Temporal and spatial variation of nitrogen and phosphorus and eutrophication assessment for a typical arid river - Fuyang River in northern China
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作者 Wenqiang Zhang Xin Jin +2 位作者 Dong Liu Chao Lang Baoqing Shan 《环境科学学报:英文版》 SCIE EI CAS CSCD 2017年第5期41-48,共8页
Based on water quality surveys over 2 years(July to December,in 2014 and 2015) in a typical arid river in northern China the Xingtai segment of the Fuyang River basin — the variation of nitrogen(N) and phosphorus(P) ... Based on water quality surveys over 2 years(July to December,in 2014 and 2015) in a typical arid river in northern China the Xingtai segment of the Fuyang River basin — the variation of nitrogen(N) and phosphorus(P) was analyzed.The extent of water eutrophication of this segment was also assessed using a universal index formula for eutrophic evaluation and a logarithmic power function.The results showed that the average concentration of total N(TN) was 27.2 mg/L(NH_3-N,63.5%),total P(TP) was 2.0 mg/L(solution reactive phosphorus,68.8%).Temporal and spatial variations of N and P in this segment were observed.Concentrations of N and P in the arid season were higher than those in the rainy season.Spatially,the N and P concentrations followed the same trend;i.e.,higher in the city segment than in the suburbs,and decreasing along the river.The water eutrophication in the studied segment reached extremely high levels at all times(eutrophication index ≥76.3).Spatially,its trend was clearly linked with N and P.Water shortage,pollution accumulation and a weak self-purification function are the main reasons for the prominent eutrophication in this segment. 展开更多
关键词 富营养化评价 干旱季节 时空变化 中国北部 河流域 氮磷 水体富营养化 阜阳
Exploration of Multi-modal Teaching Methods in Teaching of Agricultural Landscape Planning 预览
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作者 Tian HU Yarui WU +1 位作者 Dong LIU Jing HU 《亚洲农业研究:英文版》 2017年第9期72-74,共3页
Taking the teaching practice of agricultural landscape planning for example,this paper uses the multi-modal teaching idea for teaching design based on traditional lecture-style teaching,including multi-modal teaching ... Taking the teaching practice of agricultural landscape planning for example,this paper uses the multi-modal teaching idea for teaching design based on traditional lecture-style teaching,including multi-modal teaching materials,multi-modal teaching methods and multi-modal teaching evaluation. The results show that this method can effectively improve students’ interest in learning,reinforce the theoretical basis of agricultural landscape planning theory,and improve agricultural landscape planning practical skills. It is the active exploration of multi-modal teaching model and useful complement to traditional classroom teaching. 展开更多
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Secure Pairing with Wearable Devices by Using Ambient Sound and Light
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作者 LIU Dong CHEN Jing +2 位作者 DENG Qisi Arouna KONATE TIAN Zairong 《武汉大学学报:自然科学英文版》 CAS CSCD 2017年第4期329-336,共8页
便携设备通常和聪明的电话工作。为了保证仅仅合法的聪明的电话,能读数据,他们必须进行配对建立一把分享的钥匙。传统的配对方法要求配对的设备为用户相互作用有一个键盘或屏幕。由于尺寸限制,然而,键盘或屏幕是难的在便携设备被安... 便携设备通常和聪明的电话工作。为了保证仅仅合法的聪明的电话,能读数据,他们必须进行配对建立一把分享的钥匙。传统的配对方法要求配对的设备为用户相互作用有一个键盘或屏幕。由于尺寸限制,然而,键盘或屏幕是难的在便携设备被安装。解决这个问题,我们由使用周围的声音和光建议一个新奇配对方法。在这个新计划,从聪明的电话的任何配对的请求将触发便携设备颤动。仅仅在用户们在设备罐头上压 confirm 键以后,配对的过程继续。然后配对的设备在预定时间收集周围的声音和光并且由使用 Diffie-Hellman 协议建立分享的键。为了在关键建立免于潜在的 man-in-the-middle 攻击,处理,一改善联锁有健全、轻的比较的协议被进行证实键。如果配对的设备收集的声音和光是足够类似的,键被接受。否则,它被拒绝。与上下文基于配对方法的电流相比,我们的计划不在设备上强加严格的同步收集周围的上下文数据。而且,我们的计划不必收集并且把上下文的信息换作多重时间抵抗离线的蛮力攻击。试验性的结果和安全分析证明我们的计划的有效性。 展开更多
关键词 配对的设备 上下文比较 便携设备
Vegfa signaling regulates diverse artery/vein formation in vertebrate vasculatures
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作者 Daqing Jin Diqi Zhu +6 位作者 Yabo Fang Yiwei Chen Gaihong Yu Weijun Pan Dong Liu Fen Li Tao P.Zhong 《遗传学报:英文版》 SCIE CAS CSCD 2017年第10期483-492,共10页
Vascular endothelial growth factor A(Vegfa) signaling regulates vascular development during embryogenesis and organ formation.However,the signaling mechanisms that govern the formation of various arteries/veins in var... Vascular endothelial growth factor A(Vegfa) signaling regulates vascular development during embryogenesis and organ formation.However,the signaling mechanisms that govern the formation of various arteries/veins in various tissues are incompletely understood.In this study,we utilized transcription activator-like effector nuclease(TALEN) to generate zebrafish vegfaa mutants.vegfaa~(-/-) embryos are embryonic lethal,and display a complete loss of the dorsal aorta(DA) and expansion of the cardinal vein.Activation of Vegfa signaling expands the arterial cell population at the expense of venous cells during vasculogenesis of the axial vessels in the trunk.Vegfa signaling regulates endothelial cell(EC) proliferation after arterial-venous specification.Vegfa deficiency and overexpression inhibit the formation of tip cell filopodia and interfere with the pathfinding of intersegmental vessels(ISVs).In the head vasculature,vegfaa~(-/-) causes loss of a pair of mesencephalic veins(MsVs) and central arteries(CtAs),both of which usually dvelop via sprouting angiogenesis.Our results indicate that Vegfa signaling induces the formation of the DA at the expense of the cardinal vein during the trunk vasculogenesis,and that Vegfa is required for the angiogenic formation of MsVs and CtAs in the brain.These findings suggest that Vegfa signaling governs the formation of diverse arteries/veins by distinct cellular mechanisms in vertebrate vasculatures. 展开更多
关键词 血管形成 信号调节 脊椎动物 主动脉 动物多样性 静脉 血管内皮生长因子 胚胎发生
PTA链板输送系统的优化研究 预览
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作者 刘冬 迟玉春 +2 位作者 李晓娟 王婷婷 李振忠 《工程技术与管理(英文)》 2017年第2期195-196,200共3页
论文简单介绍了PTA链板输送系统的工艺流程,分析了槽车输送和吨袋输送的区别,对槽车输送时链板遇到的故障及缺陷提出了改进措施。
关键词 链板输送 槽车 故障 对策
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