Analysis of the distribution and clonality of TCR Vβ T cells in cord blood     

CHEN Shao-hua  LI Yang-qiu  YANG Li-jian  ZHANG Yu-ping  LI Qing 《园艺学报》2002,18(6):662-665

AIM:To investigate the distribution and clonality of TCR Vβ subfamily T cells in cord blood. METHODS:The CDR3 of TCR Vβ 24 subfamily genes were amplified in mononuclear cells from 13 cases of cord blood. To observe the usage of TCR Vβ repertoire, the PCR products were further labeled with fluorescent and analyzed by genescan technique for the CDR3 size, to evaluate clonality of the detectable TCR Vβ T cells. Peripheral bloods from 10 cases of normal individuals and T cell line Molt-4 and Jurkat served as controls. RESULTS:Only 38.78%±16.26% of 24 Vβ subfamily T cell were selectively expressed in cord blood, predominantly in Vβ 3, 5, 8, 9 and 13, whereas all 24 Vβ subfamilies could be detected in T cells from peripheral blood of normal individuals. Genescan analysis showed that all PCR products of TCR Vβ subfamilies from cord blood or normal individual peripheral blood displayed multi-peaks. CONCLUSION:Some TCR Vβ subfamily T cells were absent in cord blood. All TCR Vβ subfamily T cells in cord blood displayed polyclonality.  相似文献   

基于支持向量机的农机装备水平差异分类研究     

袁玉萍  安增龙 《中国农业大学学报》2015,20(4):167-173

针对黑龙江垦区各农场农机装备水平不平衡差异问题,采用支持向量机多类分类和主成分分析相结合的方法进行研究。将农机装备水平分为3个等级水平,从总量、速度和均量3方面选取10个评价指标;采用主成分分析法确定5个主要合成指标;建立多类分类支持向量机新模型,把新模型转化成一个互补问题,利用Lagrangian隐函数进一步转化成一个强凸的无约束优化问题,采取快速牛顿算法进行求解;利用实证调研数据,从发展差异度的角度对黑龙江垦区98个农场农机装备水平的差异进行多指标分析,在分类的准确度和训练速度方面都有很好的表现。  相似文献   

补播羊草和黄花苜蓿对退化草甸植物群落特征的影响     

孙伟  刘玉玲  王德平  赵敏  杨合龙  宋倩  肖红  王开丽  曹婧  戎郁萍 《草地学报》2021,29(8):1809-1817

呼伦贝尔草原区是我国北方重要的生态屏障,近年来不合理的利用方式导致该地区退化草地面积不断扩大,为了探究牧草补播时间及补播比例对呼伦贝尔退化草甸草原植物群落特征的影响,为该地区退化草地修复提供依据。本研究以羊草（Leymus chinensis（Trin.） Tzvel.）和黄花苜蓿（Medicago falcata L.）为试验材料,采用双因素随机区组试验设计,通过测定幼苗数、高度、生物量等群落指标,并综合评价补播效果,结果表明：夏播羊草和黄花苜蓿幼苗数量显著高于春播和秋播（P<0.05）,夏播和秋播植物群落总生物量呈增加趋势,春播则呈减少趋势;补播措施提高了退化草地植物群落Shannon-Weiner指数、Simpson指数和Pielou指数,豆科和禾本科植物重要值呈增加趋势,其他科植物呈下降趋势。呼伦贝尔地区夏季补播羊草和黄花苜蓿以1∶3补播效果较好,而春播由于恢复时间短,需进一步观察。  相似文献   

Analysis and FEM Simulation of the Forming Process of Front Bumper Bracket     

ZHOU Jie  ZHANG Yu-ping  WEI Guang-zhen  YANG De-sen 《保鲜与加工》2007,(7):14-17

The processing characteristics of the front bumper bracket are analyzed,and a reasonable process scheme is worked out.The three-dimensional sheet metal forming analysis software PAM-STAMP are adopted to simulate the bracket's drawing process.Then the surface of die is proved fine through analyzing the FLD diagrams and the forming results.An economical and optimized die structure is decided,and a complete set of dies of the bracket is designed.The spacing block is added in the sizing mold,which control the size precision of end products and assembling columns actively,and finally the certified products.The material utility and the labor productivity are raised,the production cost is saved,and the mold design quality and the efficiency are improved effectively.  相似文献   

低能离子注入后小麦苗期损伤效应研究   总被引：7，自引：2，他引：7  

王卫东  闻捷  苏明杰  秦广雍  霍裕平 《华北农学报》2005,20(2):80-83

以鉴54、豫农118及豫麦18号为材料,研究了不同剂量率、剂量离子注入对小麦幼苗生长的影响。结果表明,随着剂量率和剂量的增加小麦幼苗损伤程度逐渐加剧,具体表现在苗高降低、第一叶长变短。剂量率间差异显著,品种间有辐射敏感性差异。另外苗期还发现了一些变异,主要表现为主叶脉失绿和形态畸形。离子束诱变的合适剂量在6×1017ions/cm2以上。  相似文献   

车辆发动机气门弹簧的设计方法探讨     

张俊海  郑兰霞  陈艳艳  葛玉萍 《拖拉机与农用运输车》2007,34(5):34-35

发动机气门弹簧多用圆柱形螺旋压缩弹簧,在气门关闭过程中用于克服气门及传动件的惯性力,保证气门及时落座并紧密贴合,防止气门在发动机振动时产生跳动。本文通过分析其优化设计的设计变量、目标函数和约束条件,提出并验证优化设计的数学模型,该方法简便易行,且可以达到预期的设计目的。  相似文献   

一种新式护坡——模压混凝土砌块护坡     

张玉清宓永宁  诸葛妃庞海臻 徐锋 《农业机械化与电气化》2007,(6):43-45

在对传统护坡型式缺陷进行分析的基础上,介绍了一种新式护坡—模压混凝土砌块护坡,通过对其生产工艺、施工工艺以及优点等方面的阐述,说明该护坡系统有良好应用前景。  相似文献   

Estrogen treatment enhances mesenteric lymphatic contractility in rats after hemorrhagic shock     

ZHANG Li-min  FENG Niu-niu  ZHAO Chen  ZHANG Yu-ping  NIU Chun-yu  ZHAO Zi-gang 《园艺学报》2021,37(1):66-71

AIM To investigate the effects of 17β-estradiol （E2） treatment on the mesenteric lymphatic microcirculation and isolated lymphatic contractility in rats after hemorrhagic shock, and to explore the relationship between contractility and the difference between intra- and extracellular calcium ion concentrations （［Ca²⁺］） of lymphatic smooth muscle cells （LSMCs）. METHODS Male Wistar rats were divided into sham group, shock group and shock+E2 group. The rats were subjected to hemorrhage ［（40±2） mmHg for 90 min］ and resuscitation with or without subcutaneous injection of E2 （2 mg/kg）. After resuscitation for 3 h, the mesenteric lymphatic microcirculation in vivo was observed. Moreover, the isolated mesenteric microlymphatic rings were prepared for the observations of lymphatic contractility evaluated by the indexes including end-systolic diameter, end-diastolic diameter, contraction frequency （CF） and passive diameter. Meanwhile, the difference between intra- and extracellular ［Ca²⁺］ of LSMCs was recorded during lymphatic contraction. RESULTS Treatment with E2 significantly enhanced the CF, total contractile fraction and lymphatic dynamics index in vivo in the rats after hemorrhagic shock, and increased the CF, the fractional pump flow and the difference between intra- and extracellular ［Ca²⁺］ of LSMCs in isolated lymphatics from the shocked rats （P<0.05）. CONCLUSION Estrogen treatment enhances lymphatic contractility in rats after hemorrhagic shock, which is related to enhancement of difference between intra- and extracellular ［Ca²⁺］ of LSMCs.  相似文献   

河北省审定优质麦主要性状分析   总被引：1，自引：0，他引：1  

刘玉平  李亚军  陈希勇  梁新棉  赵爱菊  冯艳茹 《河北农业科学》2006,10(2):50-53

分析了1998～2005年河北省审定优质小麦品种的农艺性状、品质性状及来源.结果表明:审定品种的产量水平和株高近年来改良效果明显,基本接近于高产品种;蛋白质和稳定时间基本达到国家强筋麦标准,而湿面筋含量、吸水率和沉降值相对较低;优质基因源狭窄.优质麦育种今后应注重沉降值和吸水率的研究和选择,拓宽遗传基础.  相似文献   

大孔吸附树脂提取多杀菌素的方法   总被引：1，自引：0，他引：1  

胡西洲  贺玉平  戴经元  林开春 《华中农业大学学报》2006,25(4):397-399

采用大孔树脂吸附法提取多杀菌素。通过树脂选型,筛选出XAD-4作为多杀菌素提取的吸附剂;吸附最适pH值为11.0,流速为1/6(1/min),加入2%氯化钠;采用丙酮梯度解吸,总收率达64.7%。  相似文献