1,822 research outputs found

    Effects of FGF on the growth and development of Echinococcus multilocularis and its molecular mechanism

    Get PDF
    泡状棘球蚴病是由多房棘球绦虫续绦期幼虫引起的一种严重威胁人类生命安全的人兽共患寄生虫病,泡球蚴在宿主体内的生长发育过程受到宿主生长因子的影响。本文在实验室成功构建的泡球蚴体外培养体系的基础上,探讨宿主成纤维生长因子FGF与泡球蚴生长发育的相互关系,并初步阐述了FGF通过调控泡球蚴体内的ERK信号通路影响泡球蚴生长发育的分子机制。本文主要包括以下内容: (1)FGF影响体外培养泡球蚴的生长过程。分别从FGF影响泡球蚴囊泡的存活率、生长率来阐述FGF对于泡球蚴的生长过程的影响。在有血清和无血清培养液中,FGF均可以延长泡球蚴存活的时间,提高囊泡的存活率,尤其是在FGF浓度为50ng/ml时最为明...Alveolar echinococcosis, caused by the metacestode larval stage of the cestode Echinococcus multilocularis, is one of the parasitic zoonoses which seriously threaten our safety. Understanding the growth and development process of the parasite and the related factors is very important. Based on the in vitro culture system successfully established in our lab, we investigated the effect of fibroblas...学位:理学硕士院系专业:生命科学学院_细胞生物学学号:2162012115242

    A Kidney Tumors Segmentation Algorithm from CT Image Based on Texture

    Get PDF
    由于肿瘤的形状不规则以及CT图像中软组织之间灰度相似,边界模糊,导致基于CT图像的肿瘤分割一直是一个国际难点。针对肾脏肿瘤和肾脏灰度相似导致难以分割肾脏肿瘤这一问题,提出了一种基于纹理特征的肾脏肿瘤分割算法。算法首先提取出最能体现肾脏肿瘤和肾脏差异的纹理特征,再对其进行有效性选择,最后采用加权欧氏距离分割出肾脏肿瘤,取得了良好的分割效果。Because of the irregularity of shape, gray similarity and blur boundary of soft tissues in CT images, tumor segmentation is always an international difficulty. In this paper, an algorithm based on texture is proposed for kidney tumor segmentation from kidneys. The algorithm first extracts texture features of kidney and kidney tumors, and then selects effective features; finally, weighted Euclidean distance is used for segmentation. This algorithm for kidney tumor segmentation achieved good result

    Advances in the Study of Arbuscular Mycorrhizal Fungi in High Altitude and Cold Habitats on Tibetan Plateau

    Get PDF
    极端生境往往蕴藏着具有特殊生理生态功能的生物类群.海拔高、温度低、生长季节短的青藏高原高寒草原生态系统是典型的极端生境之一,目前有关该生境中分布的丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)研究已引起广泛关注.本文从青藏高原高寒生境中AM真菌的研究概况入手,论述青藏高原高寒生境中AM真菌的群落组成、物种多样性与分布特征、菌根侵染发育状况及高寒生境对AM真菌的影响.指出高寒生境中AM真菌群落结构研究方面存在的问题,探讨解决这些问题的可能途径及其研究发展前景,以期为青藏高原高寒草原生态系统稳定性的维持与受损生态系统的恢复提供理论依据.There are many special organisms in extreme habitats. Tibetan Plateau alpine meadow e- cosystem is one of the most important extreme habitats in terrestrial ecosystem, it has the character- istics with high altitude, low temperature, and short growing season. Nowadays, the studies of ar- buscular mycorrhizal (AM) on Tibetan Plateau has been widely concerned. This review mainly dis- cussed on AM fungi communities composition, AM fungi diversity and their distribution character- istics, AM colonization feature, and abiotic factors on the effect of AM fungi. At the same time, the shortcomings about the heterogeneity of adverse habitats on AM fungi communities were pointed out for further study. Based on this, these research achievements were summarized in order to pro- vide a theoretical basis for the maintenance of the stability in Tibetan Plateau alpine steppe ecosys- tem.国家自然科学基金项目(31270558),上海科技馆引进高层次人才科研启动经费(2015)

    Applying Real Option Method To The Oil & Gas Exploration and Production Project

    Get PDF
    随着中国经济的高速发展,中国对能源的需求越来越大,而作为世界第一战略物资的石油对中国经济的继续发展起到了举足轻重的作用。为了满足中国对能源的需求,我们除了大量进口原油外,还需要科学的勘探开发本土的油气资源。然而目前国内在评价油气资源价值上仍延用20世纪90年代初期的投资评价方法,忽略了石油勘探开发项目的特殊性,从而造成了较大的偏差,错失投资良机,因此,开发一种灵活有效的评价方法就显得非常的重要。 贴现现金流量指标实际上都是通过分析项目寿命期内现金流量序列后计算获得的,其在计算过程中暗含以下两个假设:(1)项目投资机不可失,投资在期初或某一时刻必然发生;(2)只要投资一旦发生,经营者对投资结果...Petroleum, the "blood of industry", is an important chip in political, military and diplomatic relations. In the past 50 years, international contests surrounding the petroleum resources have never stopped and conflicts and wars in many regions are closely related to oil. The competition in this field has long gone beyond the category of general commerce. As China’s economy is blooming rapidly, p...学位:理学硕士院系专业:海洋与环境学院环境科学与工程系_环境科学学号:20043404

    Study on Electronic Money and Monetary Policy Effectiveness in China

    Get PDF
    电子货币是随着计算机技术和网络技术在金融领域的应用而产生的一种新型信用货币。电子货币的产生被认为是继中世纪法币取代铸币以来,货币形式发生的第二次标志性变革。与传统的货币形式相比,电子货币具有成本低、独立性强、移动方便快捷、易分割和安全性高等优势,这种以崭新技术支撑的货币形式给人们带来了全新的感受与便利的同时,也给传统的货币金融理论带来了前所未有的挑战,尤其是对货币政策有效性的冲击尤为明显。因此有必要对电子货币和货币政策有效性进行全面深入的研究,这不但可以丰富货币理论,为电子货币的健康发展提供指导,而且研究结论可以为中央银行在制定和实施货币政策时提供科学合理的理论依据,对中央银行提高货币政策有效...Electronic money which is generated with the application of computer technology and network technology in the financial sector is a new type of credit money. Generation of electronic money is considered as the second landmark change of currency form after the legal tender taking replace of the Mint in medieval times. Compared with the traditional form of currency,electronic money has advantages as...学位:经济学博士院系专业:经济学院_网络经济学学号:1552010015373

    Analysis and Design of Xinjiang Community Management Service Information Platform

    Get PDF
    随着科学技术的发展、社区管理服务的日益复杂化,社区管理服务信息化建设已成为必然趋势。然而,新疆社区管理服务信息建设仍然处于初级阶段,信息技术使用率较为低下,尚未完成使用计算机自动化处理社区相关服务的目标,社区工作涉及的信息量大,社区工作人员的工作任务越来越繁重。将社区管理服务信息平台引入社区管理工作中,对社区进行信息化管理,不仅能够提高社区工作人员的工作效率、降低社区工作成本,而且它能够成为社区工作人员与社区居民交流的桥梁和纽带,更好的掌握辖区常住人口和流动人口的情况,使社区更好的完成维护社会稳定和为民服务两项任务。 本文就开发一个通用的社区管理服务信息平台展开工作,首先分析了开发本平台的背...With the science and technology developing, the more complexity of community management services, community management and service information construction have become an inevitable trend. However, the information construction of community management and service in Xinjiang is still in its infancy, information technology utilization rate is relatively low, using computer automated processing commu...学位:工程硕士院系专业:软件学院软件工程系_工程硕士(软件工程)学号:X201223099

    DESIGN OF A CHARGE-PUMP PHASE-LOCKED LOOP USED FOR SERDES TRANSRECEIVER

    Get PDF
    近年来由于计算机处理速度和网路的快速发展,电子工业界兴起了一股向数据传输和高速串行数据通信研究的热潮。传统并行接口技术已无法满足数据传输数率的进一步提高,过去主要用于光纤通信的串行通信技术—SerDes正逐步取代传统并行总线而成为高速接口技术的主流。 SerDes是一种时分多路复用(TMD)、点对点的通信技术,即在发送端多路低速并行信号被转换为高速串行信号,经过传输线,最后在接收端高速串行信号重新转换成低速并行信号。这种串行技术充分利用传输媒体的信道容量,减少所需的传输信道和器件引脚数,从而大大降低了通信成本。本论文实现了一款用于SerDes接口发送端和接收端的电荷泵锁相环,将25MHz到8...Under the development of the network and computer operator speed in recent years, a trend of data transmission and study at high-speed serial communication is growing. The conventional parallel bus interface technology is unable to meet the increasing speed of data transmission. Serial link interface used in optical fiber communication in the past ---SerDes is replacing gradually the conventional ...学位:工学硕士院系专业:物理与机电工程学院物理学系_微电子学与固体电子学学号:1982007115231

    基于自适应权重AD-Census变换的双目立体匹配

    Get PDF
    针对AD-Census变换采用固定权重将AD变换代价与Census变换代价合成的双目立体匹配代价无法体现像素点区域特征的问题,提出一种基于自适应权重AD-Census变换的双目立体匹配算法。算法首先通过增加相邻像素点的灰度差阈值条件改善十字支撑自适应窗口;然后以每个像素点的十字支撑自适应窗口的最短臂长为自变量,利用指数形式的函数,进行AD变换代价与Census变换代价合成权重的自适应设置。由于像素点十字支撑自适应窗口的最短臂长能够反映像素点的区域特性,因此自适应设置的权重大小与像素点的区域特性直接相关,计算图像边缘区域像素点的匹配代价时,AD变换的权重大;计算平滑区域像素点的匹配代价时,Census变换的权重大。Middlebury第3代双目立体匹配评估平台的结果显示,基于自适应权重AD-Census变换的双目立体匹配性能与基于AD-Census变换的双目立体匹配性能相比,所有图像集的全部像素点的视差平均误差减小了25%,非遮挡像素点的视差平均误差减小了20%,性能得到了提升;平台上包括Adir在内的多个图像集的匹配结果表明基于自适应权重AD-Census变换的双目立体匹配更适合含纹理丰富、存在重复区域的图像。国家自然科学基金资助项目(61274133
    corecore