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Antiangiogenic effect of somatostatin receptor subtype 2 on pancreatic cancer cell line:Inhibition of vascular endothelial growth factor and matrix metalloproteinase-2 expression in vitro

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World Journal of gastroenterology 2004年第3期10卷 393-399页

作者： ManojKumar zheng-RenLiu LaxmiThapa QingChang da-YuWang Ren-YiQin DepartmentofSurgery TongjiHospitalTongjiMedicalCollegeHuazhongUniversityofScienceandTechnologyWuhan430030HubeiProvinceChina DepartmentofObstetricsandgynecology TongjiHospitalTongjiMedicalCollegeHuazhongUniversityofScienceandTechnologyWuhan430030HubeiProvinceChina

AIM:To investigate the anti-angiogenic effect of somatostatin receptor subtype 2 (SSTR2) gene transfer into pancreatic cancer cell line PC-3, and the mechanisms involved in this ***: The full length human SSTR2 cDNA was introduced into pancreatic cancer cell line PC-3 by lipofectamine-mediated transfection. Positive clones were screened by g418 and stable expression of SSTR2 was detected by immunohistochemistry SABC methods and RT-PCR. Enzyme-linked immunosorbent assay (ELISA) was used to detect vascular endothelial growth factor (VEgF) levels in the cell culture supernatants of SSTR2-expressing cells, vector control and mock control cells. Furthermore, the expressions of VEgF and matrix metalloproteinase-2 (MMP-2) were detected by immunohistochemistry SABC methods and RT-PCR in these ***: VEgF levels in the cell culture supernatants were significantly reduced in the SSTR2-expressing cells (first week,172.63±21.2ng/L and after two months, 198.85±26.44ng/L)compared with the vector control (first week, 790.39±86.52ng/L and after two months, 795.69±72.35ng/L) and mock control (first week, 786.42±90.62ng/L and after two months,805.32±84.36ng/L) (Pgnificant reduction of the integral optical density of VEgF and MMP-2 in the SSTR2-expressing cells (42.25±8.6 and 70.5±6.25, respectively) compared with the vector control (85.75±12.9 and 110.52±13.5, respectively) and mock control (82.6±9.28 and 113.56±9.62,respectively) (Pge gray value of VEgF and MMP-2 was significantly increased in the SSTR2-expressing cells (121.56±8.43 and 134.46±19.95, respectively) compared with the vector control (55.72±5.6 and 62.26±12.68,respectively) and mock control cells (58.48±6.2 and 65.49±9.16, respectively) (PgF mRNA and MMP-2 mRNA were significantly reduced in the SSTR2-expressing cells (0.1384±0.017 and 0.2343±0.070, respectively) compared with the vector c

关键词：胰腺癌基质金属蛋白酶-2 肿瘤抑制血管内皮生长因子生长抑制素受体亚型2 肿瘤血管生成

Oxidation of a Co-base Superalloy

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Journal of Materials Science & Technology 2008年第6期24卷 883-890页

作者： guichen HO U Zhiyuan LIU Hua WEI Qi zheng Xiaofeng SUN Hengrong g UAN Zhuangqi HU Superalloy Division Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China China Aviation Powerplant Research Institute Zhuzhou 412002 China

The oxidation behavior of a cast polycrystalline Co-base superalloy was studied at temperatures from 900 to 1050℃ and analyzed by thermogravimetric analysis （Tga）, X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The results indicate that a cast Co-base superalloy follows the subparabolic oxidation kinetics at 900 and 1000℃, which are controlled by the growth of the inner Cr-rich layer, and that after oxidation at 1050℃ for 200 h, it almost exhibits the linear oxidation kinetics possible due to the volatility of Cr-rich oxide. A mixed scale forms on the alloy after prolonged oxidation. The oxide scale formed at 900 and 1000℃ is composed of an outer layer of spinel and an inner continuous Cr-rich layer and at I050℃ is composed of a very discontinuous Cr-rich layer.

关键词： Co-base superalloy Oxidation Kinetics Microstructure

Research progress on corrosion behaviors and biocompatibility of rare-earth magnesium alloys in vivo and in vitro

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Journal of Rare Earths 2023年第12期41卷 1827-1842,I0001页

作者： Yuan Zhang Yun Liu Ruining zheng Yaqi zheng Liansheng Chen Key Laboratory of the Ministry of Education for Modern Metallurgy Technology North China University of Science and TechnologyTangshan063210China School of Metallurgy and Energy North China University of Science and TechnologyTangshan063210China

As yet,Mg alloys acting as the medical implants have drawn extensive attention,due to their spontaneous degrada bility,effective load-transmissibility and the excellent biocompatibility,particularly in bone tissue reconstruction and vascular ***,they were inevitably affected by the tension/compression-torsion,dynamic erosion and corrosion fatigue under complex service conditions,which lead to premature failure of ***-alloying addition is an effective way to delay the rapid degradation,especially in rare-earth micro-composite *** can not only reduce intensities of galvanic-corrosion by refining the grain sizes and adjusting the Volta-potentials distribution of the precipitates,but also modify the compositions and biocompatibility of the degradation ***,the higher compress tress on the surface can improve the stability and densification of the film layer,which enhanced the corrosion ***,the latest research progress about in vivo/vitro degradation behavio rs and bioco mpatibility of rare-earth Mg alloys is reviewed;The internal relationships between rare-earth elements,phase features and degradation behaviors of Mg alloys are ***,the effects of rare-earth addition on the film-characteristics are deeply explained,and the induced mechanisms of rare earth elements on the biocompatibility are revealed.

关键词： Mg alloys Rare-earth elements Microstructure Degradation behaviors Biocompatibility

Study on High-Performance Computing for Simulation of End Milling Force

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厦门大学学报（自然科学版） 2002年第S1期41卷 183-184页

作者： ZhaNg Zhi-hai, zheng Li, LI Zhi-zhong, LIU da-cheng, ZhaN g Bo-peng (Department of Industry Engineering, Tsinghua University, Beijing 1000 84, China)

Milling Process Simulation is one of the important re search areas in manufacturing science. For the purpose of improving the prec ision of simulation and extending its usability, numerical algorithm is more and more used in the milling modeling areas. But simulative efficiency is decreasin g with increase of its complexity. As a result, application of the method is lim ited. Aimed at above question, high-efficient algorithm for milling process sim ulation is studied. It is important for milling process simulation’s applicatio n. Parallel computing is widely used to solve the large-scale computation question s. Its advantages include system flexibility, robust, high-efficient computing capability and high ratio of performance to price. With the development of compu ter network, utilizing the computing resource in the Internet, a virtual computi ng environment with powerful computing capability can be consisted by microc omputers, and the difficulty of building hardware environment which is used to s upport parallel computing is reduced. How to use network technology and parallel algorithm to improve simulative effic iency for milling forces simulation is investigated in the paper. In order to pr edict milling forces, a simplified local milling forces model is used in the pap er. End milling cutter is assumed to be divided by r number of differential elem ents along the axial direction of the cutter. For a given time, the total cuttin g forces can be obtained by summarizing the resultant cutting force produced by each differential cutter disc. Divide the whole simulative time into some segmen ts, send these program’s segments to microcomputers in the Internet and obtain the result of the program’s segments, all of the result of program’s segments a re composed the final result. For implementing the algorithm, a distributed Parallel computing framework is de signed in the paper. In the framework, web server plays a role of controller. Us ing Java RMI(remote method int

关键词： end-milling force model simulation high-perfo rmance computing parallel algorithm Java RMI

Simulation of Wave-Flow-Cavitation Interaction Using a Compressible Homogenous Flow Method

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Communications in Computational Physics 2013年第7期14卷 328-354页

作者： J.g.zheng B.C.Khoo Z.M.Hu Department of Mechanical Engineering National University of SingaporeSingapore 119260 Singapore-MIT Alliance National University of SingaporeSingapore 117576 Temasek Laboratories National University of SingaporeSingapore 117411

A numerical method based on a homogeneous single-phase flow model is presented to simulate the interaction between pressure wave and flow *** account for compressibility effects of liquid water,cavitating flow is assumed to be compressible and governed by time-dependent Euler equations with proper equation of state(EOS).The isentropic one-fluid formulation is employed to model the cavitation inception and evolution,while pure liquid phase is modeled by Tait equation of *** of large stiffness of Tait EOS and great variation of sound speed in flow field,some of conventional compressible gasdynamics solvers are unstable and even not applicable when extended to calculation of flow *** overcome the difficulties,a godunov-type,cell-centered finite volume method is generalized to numerically integrate the governing equations on triangular *** boundary is treated specially to ensure stability of the *** method proves to be stable,robust,accurate,time-efficient and *** numerical experiments are designed to investigate unsteady dynamics of the cavitating flow impacted by pressure wave,which is of great interest in engineering applications but has not been studied systematically so *** simulation indicates that cavity over cylinder can be induced to collapse if the object is accelerated suddenly and extremely high pressure pulse results almost ***,however,may be avoided by changing the traveling speed *** accompanying huge pressure increasemay damage underwater ***,cavity formed at relatively high upstream speed may be less distorted or affected by shock wave and can recover fully from the initial *** is observed that the cavitating flow starting from a higher freestream velocity is more stable and more resilient with respect to perturbation than the flow with lower background *** findings may shed some light on how to control cavitation development

关键词： Cavitating flow isentropic cavitation model shock-flow-cavitation interaction

An Interface-Capturing Method for Resolving Compressible Two-Fluid Flows with general Equation of State

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Communications in Computational Physics 2009年第10期6卷 1137-1162页

作者： T.S.Lee J.g.zheng S.H.Winoto Department of Mechanical Engineering National University of SingaporeSingapore 119260

In this study,a stable and robust interface-capturing method is developed to resolve inviscid,compressible two-fluid flows with general equation of state(EOS).The governing equations consist of mass conservation equation for each fluid,momentum and energy equations for mixture and an advection equation for volume fraction of one fluid *** of pressure equilibrium across an interface is used to close the model ***-hancock scheme is extended to construct input states for Riemann problems,whose solutions are calculated using generalized HLLC approximate Riemann *** mesh refinement(AMR)capability is built into hydrodynamic *** resulting method has some ***,it is very stable and robust,as the advection equation is handled ***,general equation of state can model more materials than simple EOSs such as ideal and stiffened gas EOSs for *** addition,AMR enables us to properly resolve flow features at disparate ***,this method is quite simple,time-efficient and easy to implement.

关键词： MUSCL-hancock scheme adaptive mesh refinement compressible two-fluid flows general equation of state

Outage probability analysis for superposition coded symmetric relaying

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Science China(Information Sciences) 2013年第2期56卷 65-73页

作者： WU Yi zheng Meng FEI ZeSong LARSSON Erik g. KUANg JingMing Modem and Common IP Development ST-Ericsson Nya Vattentornet Research Centre of Digital Communication Technology (RCDCT) School of Information and Electronics Beijing Institute of Technology Department of Electrical Engineering (ISY) Linkping University

Superposition coded symmetric relaying is a bandwidth-efficient cooperative scheme where each source node simultaneously transmits both its own "local" packet and "relay" packet that originated at its partner by adding the modulated local and relay signals in Euclidean space. This paper investigates the power allocation and outage probability of a superposition coded symmetric relaying system with finite-constellation signaling. We first derive the mutual information (MI) metrics for the system. The derived MI metrics consist of two parts: one represents the MI conveyed by the modulated signal corresponding to its own data, and the other represents the MI conveyed by the modulated signal corresponding to its partner’s data. Using MI based effective signal-to-noise ratio mapping technique, we attain expressions for the outage probability. Furthermore, we discuss power allocation policies that minimize the outage probability. Simulation results are presented to verify the correctness of the outage probability analysis and the benefits of the power allocation.

关键词： superposition coding symmetric relaying mutual information outage probability power allocation

基于指数滤波模型的青藏高原根系层土壤水分估算研究

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高原气象 2025年第1期44卷 134-149页

作者：宋雨曦苏建宾文军郑东海成都信息工程大学大气科学学院高原大气与环境四川省重点实验室四川成都610225 中国科学院青藏高原研究所青藏高原地球系统与资源环境全国重点实验室国家青藏高原科学数据中心北京100101

高精度、长时序的土壤水分数据对青藏高原陆-气相互作用研究十分重要。然而,当前青藏高原土壤水分研究大多聚焦表层土壤水分的卫星反演,根系层土壤水分的估算研究相对匮乏。基于青藏高原五个土壤水分观测网络(狮泉河、帕里、那曲、黑河... 详细信息

高精度、长时序的土壤水分数据对青藏高原陆-气相互作用研究十分重要。然而,当前青藏高原土壤水分研究大多聚焦表层土壤水分的卫星反演,根系层土壤水分的估算研究相对匮乏。基于青藏高原五个土壤水分观测网络(狮泉河、帕里、那曲、黑河上游、玛曲)数据,本文系统评估了指数滤波模型在青藏高原不同气候与下垫面区域估算根系层(10 cm/20 cm/40 cm)土壤水分的适用性,探讨了不同环境因素(土壤、气候、植被)对模型特征时长参数T值的影响,最后评估了利用三种方法(各观测网络或青藏高原站点最优T值(Topt)中位数、随机森林模型)获取的区域T值估算青藏高原根系层土壤水分的可靠性。研究发现:(1)随着土壤深度的增加,根系层与表层土壤水分的相关性降低,而其空间异质性增大,导致指数滤波模型的应用精度降低,而模型T值及其空间异质性增大;(2)空间上随着降水量和土壤含水量的增加,根系层与表层土壤水分的相关性增大,而其空间异质性降低,使得指数滤波模型的应用精度上升,而其在区域内不同站点应用精度的差异呈现降低趋势;(3)土壤性质尤其是砂土含量是控制青藏高原区域T值空间分布的主要因素;(4)T值的获取对指数滤波模型在青藏高原的应用精度影响较小,当前常用的区域Topt中位数和随机森林模型均能获取相对合理的区域T值和取得一致且相对准确的模拟结果。本研究的发现有望推动利用指数滤波模型基于卫星表层土壤水分资料准确获取青藏高原根系层土壤水分。

关键词：青藏高原指数滤波模型根系层土壤水分不同气候与下垫面区域

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Flexible and stretchable metal oxide gas sensors for healthcare

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Science China(Technological Sciences) 2019年第2期62卷 209-223页

作者： zheng XiaoQi CHENg HuanYu Department of Engineering Science and Mechanics The Pennsylvania State University University Park School of Physical Science and Technology ShanghaiTech University Materials Research Institute the Pennsylvania State University University Park

Capable of measuring volatile biomarker produced by the metabolism from several secretion pathways, flexible and stretchable metal oxide gas sensors have received increasing attention and their development for healthcare starts to gain *** of semiconducting metal oxide on a soft, thin, flexible substrate is the key to enable the flexible property to the gas sensor and such integration typically involves either a direct growth or post transfer of the metal oxide on or to the flexible substrate. In addition to the planar plastic substrate, textile represents another important class of flexible substrates due to its ease of integration with clothing. Moreover, the integration of metal oxide on a single fiber provides a great versatility for different applications. Though flexible sensors can easily conform to the developable surface(e.g., cylinder or cone) from a bending deformation, the conformal contact between the sensor and the tissue surface that is often non-developable requires the sensor to be capable of stretching. Due to the intrinsically brittle nature of the semiconducting metal oxide, several stretchable structures have been explored. Despite the great strides made to the burgeoning area of flexible and stretchable metal oxide gas sensors,grand challenges still need to be overcome before the technology can be applied for the practical application. The selected challenges discussed in this mini-review also represent a fraction of possibilities and opportunities for the research community in the future.

关键词： metal oxide gas sensor flexible and stretchable properties structural design strategies volatile biomarker