Diagnosis of African horsesickness

African horsesickness (AHS) is a very serious, non-contagious disease of horses and other solipeds caused by an arthropod-borne orbivirus of the family Reoviridae. The epizootic nature of the disease makes rapid, accurate diagnosis of AHS absolutely essential. Currently, diagnosis of AHS is based on typical clinical signs and lesions, a history consistent with vector transmission and confirmation by laboratory detection of virus and/or anti-AHS virus antibodies. The clinicopathologic presentation of AHS, current and next generation laboratory diagnostic methods are discussed.     

甘肃高寒阴湿区几种土壤养分限制因子研究

应用土壤养分状况综合评价法,对甘肃省高寒阴湿区4种主要农田土壤的11种养分状况进行了实验室分析、吸附试验和温室盆栽诊断,结果证明:(1)养分亏缺顺序为扁坡黑麻土N＞P＞Zn＞S,何马家黑麻土N＞P＞K＞S＞Mn＞Zn,黄绵土P＞N＞B＞Mo＞K＞S,红粘土N＞P＞Cu＞Mo＞S,其它元素可满足作物生长需要.(2)上述方法能较好地用来评价土壤养分状况并能快速和比较准确地确定土壤养分的限制因子及其缺乏程度.     

囊虫病免疫诊断检测方法的研究进展

由于科学技术的发展,囊虫病免疫诊断检测方法有了很大的进展,主要有1.免疫学检测方法,包括酶联免疫吸附法(ELISA)、斑点酶联免疫吸附法(Dot-ELISA)、生物素-亲和素酶联免疫吸附法(BAS-ELISA)、单克隆抗体酶联免疫吸附试验(McAb-ELISA)、酶联免疫印渍技术(ELIB);2.基因检测技术,包括DIG标记DNA探针、细胞因子基因检测方法、基因重组技术;3.免疫试剂盒的应用,包括循环抗原酶联免疫试剂盒、猪囊虫短程抗体IgG4快速ELISA检测试剂盒等。     

马铃薯氮素营养状况的SPAD仪诊断

以马铃薯品种克新1号为材料,研究了叶片SPAD值、叶片全氮含量、叶绿素含量以及块茎产量随供氮水平的变化规律及相互关系,旨在为使用叶绿素仪进行马铃薯无损伤氮素诊断和推荐施肥奠定基础。研究结果表明,从马铃薯苗期到块茎淀粉积累各个生育阶段叶片的SPAD测定值均与马铃薯叶片含氮量呈显著正相关关系。除苗期外,块茎形成期、块茎膨大期、淀粉积累期的马铃薯叶片含氮量和叶片SPAD值随土壤施氮量的变化均表现为线形加平台的模式。因此马铃薯块茎形成期后叶片的SPAD读数可揭示马铃薯的氮素营养状况。统计分析结果还表明,叶片SPAD值与块茎相对产量呈线形加平台的数量关系模式,据此确定了应用叶绿素仪SPAD-502进行马铃薯推荐施肥的SPAD临界值为块茎形成期47.3、块茎膨大期45.1、淀粉积累期40.2。     

Cloning and Expression of Actinobacillus pleuropneumoniae Gene Coding for TbpA and Development of an Indirect TbpA-ELISA

This study presents the cloning and expression of gene encoding transferrin-binding protein A from Actinobacillus pleuropneurnoniae in Escherichia coli expression system and the development of an indirect TbpA-ELISA. The gene coding TbpA was amplified from the A. pleuropneumoniae serotype 2 genome using polymerase chain reaction and cloned to pET-28b expression vector under the control of strong, inducible T7 promoter. The recombinant plasmid was expressed in E. coli BL21 （DE3）. The expressed fusion protein was analyzed using SDS-PAGE and Western blotting. The diagnostic potential of recombinant TbpA （rTbpA） was evaluated through an antibody-detection indirect ELISA based on the purified rTbpA. The TbpA antibodies were detectable in mice on day 7 after vaccination with purified rTbpA protein or infection with A. pleuropneumoniae serotype 10 with the TbpA-based ELISA. In addition, the TbpA-ELISA was able to detect 12 serotyping rabbit antisera postinoculation （PI） with A. pleuropneumoniae 12 serotypes experimentally. The comparable result was obtained by detecting the 117 clinical serum samples using, respectively, the TbpA-ELISA and indirect hemagglutination test （IHA） based on multiplex antigen. The result indicates that the TbpA-ELISA was the more sensitive method compared with the Mix-IHA method because of its consistent presence in A. pleuropneumoniae serotypes. In conclusion, the conserved TbpA of A. pleuropneumoniae can be used for the development of a cross-serotype diagnostic method for the detection of antibodies against A. pleuropneurnoniae.     

基于光谱红边参数的棉花黄萎病叶片氮素含量诊断研究

 以黄萎病胁迫下棉花叶片为供试材料,分析了黄萎病棉叶氮素含量(LNC)与光谱红边参数间的关系,建立了黄萎病棉叶LNC(Leaf nitrogen content) 的光谱红边参数诊断模型。结果表明：(1) 随着黄萎病严重程度的增加,棉叶LNC逐渐减小,且差异显著;（2）黄萎病棉叶红边参数红边位置(REP) 、红边振幅（Dr）、红谷位置(Lo) 、红边深度（Depth₆₇₂）和红边面积(Area₆₇₂) 均减小,红边宽度(Lwidth) 增加,且Area₆₇₂的值减小的幅度最大,Dr减小的幅度最小,Lwidth的值增加的幅度较大; (3) 黄萎病棉叶LNC含量均与红边参数REP、Lo、Depth₆₇₂和Area₆₇₂呈极显著正相关,与Lwidth呈极显著负相关,与Dr未达显著相关;(4)基于红边参数建立的黄萎病棉叶LNC含量的诊断模型均达到极显著水平（P<0.01）,其中以Area₆₇₂为自变量建立的黄萎病棉叶LNC的诊断模型的精度最高,R²超过0.7,RMSE小于0.6,RE小于0.007,能很好地诊断黄萎病棉叶LNC。     

奶牛腐蹄病节瘤拟杆菌PCR检测法研究

腐蹄病是指侵害指（趾）间皮肤及皮肤更深层软组织的急性或亚急性炎症。患病皮肤常坏死、裂开，炎症从指（趾）间皮肤蔓延到蹄冠、系部和球节，病肢明显跛行，并伴有全身性症候。腐蹄病是奶牛蹄病中危害性极为严重的一类疾病，病畜食欲减退、泌乳量下降、繁殖能力降低，病情严重者将被迫淘汰，严重影响奶牛业的发展，造成严重的经济损失。鉴于该病对奶牛业的严重危害，奶牛出现蹄病时的及时、准确临床诊断，以及与其他蹄病的鉴别诊断，对于奶牛蹄病的临床治疗和预防具有重要的实际指导意义。本试验根据节瘤拟杆菌纤毛蛋白基因序列的特异性，设计1对引物BPP并建立了PCR检测方法。试验结果表明，引物BPP具有相对较高的特异性和敏感性，其敏感性达到了152.5 pg，且引物FLP具有很好的特异性，能够准确诊断出节瘤拟杆菌的存在。     

应用血小板计数对奶牛进行超早期妊娠诊断的研究

应用血小板计数对具有正常繁殖机能的249头黑白花奶牛进行超早期妊娠诊断的研究,结果较为满意。首先对51头黑白花奶牛进行最佳血检时间的试验,结果表明,30头妊娠母牛于配种后第7天血小板明显减少(p<0.01),而21头未妊母牛则无明显变化(p>0.05);根据妊娠母牛配种前与配种后第7天血小板数之差等于或大于70×10~3/mm~3为妊娠之标准,对198头母牛进行超早期妊娠诊断试验,经“直检”妊娠及空怀的符合率分别为80.67％(96/119)和89.87％(71/97);总符合率为84.34％(167/198)。     

企业上市行为绩效的诊断分析

针对企业上市行为对绩效变化影响的问题,结合医学诊断方法,从短期和长期角度分析了公司上市行为对各行业绩效的影响。实证结果表明:企业通过改造上市后,短期内对业绩影响趋势不明显,但对资本结构有明显改善作用;从长期看,企业选择上市行为则对公司业绩有较显著的改善和促进作用。     

发动机动力不足故障诊断方法研究

动力不足是发动机常见故障之一,故障原因繁杂是发动机故障诊断的难点.基于混合气浓度及点火提前角控制的试验研究阐述了发动机动力不足的4方面原因,给出了故障状态下混合气特征值和点火提前角的变化规律,比较全面地总结了可能发生故障的部位,并给出了故障诊断流程.